Taxonomy and distribution of the anomalous "straight-line" pagurids (Crustacea) of the Eastern Pacific

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TAXONOMY AND DISTRIBUTION OF THE ANOMALOUS "STRAIGHT-LINE" PAGURIDS (CRUSTACEA) OF THE EASTERN PACIFIC

A Thesis Presented to the Faculty of the Department of Zoology The University of Southern California

In Partial Fulfillment of the Requirements for the Degree Master of Science

by Bryce C. Walton August 1950

UMI Number: EP67197

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2.

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This thesis, w ritte n by

....BRYGE„C...W^Tg.N.................. under the guidance o f h is .... F a c u lty Com m ittee, and approved by a l l its members, has been presented to and accepted by the C o uncil on G raduate Study and Research in p a r tia l f u l f i l l ­ ment of the requirements f o r the degree of

MASTER OF SCIENCE

Date.

AUG

1950

Faculty Committee

Chairman

TABLE OF CONTENTS

Page Introduction

...............

1

A c k n o w l e d g e m e n t s .....................

4

General Objective ................................

5

Specific Objectives.. ............................

5

Definition of Terms. •

.........................

7

Status of Sub-families............................

9

............................

14

Conclusions on Distribution .....................

71

S u m m a r y ..........................................

75

Literature Cited

................................

76

......................................

82

Systematic Section

Charts Plates

•

91

INTRODUCTION Within the family Paguridae, the so-called "Hermit Crabs," there is a small group which differs from the rest of the family in the possession of an uncoiled abdomen, and, in most cases, a symmetrically developed tail fan, although the abdominal appendages are completely suppressed on the right side. The collections of the Allan Hancock Foundation at the University of Southern California include the greatest aggregation of Pacific straight-line pagurids available in any one place.

These collections from the Eastern Pacific

between Oregon and Ecuador, made in the period from 1931 to date, are the basis for the present study.

A total of over

600 specimens from this anomalous group were examined. In the majority of the pagurids the abdomen is strongly coiled to the right, an arrangement which admirably adapts them for life in the cast-off shells of gastropods, which, as a rule, are dextrally coiled.

This asymmetry has a strong

hereditary basis and persists in forms which do not live In spiral shells, such as Troglopagurus which lives in holes In coral, and in the common California species, Paguristes bakeri, which often is found in sponges.

Milne-ldwards and

Bouvier (1893) report that the dextral coiling also persists in those rare abnormal individuals that adapt themselves to

2

a sinistral shell.

Another indication that this coiling is

more than superficial is given in the results of a behavior study (McKay 1945) in which Calcinus herbsti de Man was shown to turn predominately to the left when placed in a f,T tf shaped tunnel, as would be expected from animals that are spirallj/ constructed. Alcock (1905) believes that the straight-line pagurids are derived from coiled forms and that their symmetry is secondarily acquired and superficial as ^proved by the fact that the posterior abdominal appendages .... exist only on the left side.*

However, if the possibility is considered

that unilateral development of abdominal appendages is not necessarily a secondary result of coiling of the abdomen, but to be regarded as a separate phenomenon, part of this straight-line group might prove to be useful in determining the more immediate steps in the phylogenetic development of the Paguridae from the supposed pylochelid ancestors.

It is

quite possible that a detailed study of this group might dis­ close that some of them stem, not from asymmetrical forebears, but directly from the Pylochelidae.

This family, which is

paguroid in general form, resembles the Macrura in the possession of well formed and calcified abdominal terga and in the bilateral development of the abdominal appendages although the pleura have been lost as in the Paguridae. The postulation of a stage in which reduction of

3

the terga, and unilateral suppression of abdominal appendages has occurred, but in which the abdomen remains primitively uncoiled, would fill a rather large gap now existing in the very gradual intergradation between forms having macruran characters and the Brachyura, or true crabs,

Several of

these straight-line forms seemingly agree with this postu­ lated phylogenetic stage. The pagurids which possess this anomalous uncoiled abdomen fall into seven genera, all quite small: Cancellus Milne-Edwards 1836 Paguropsis Henderson 1888 Tylaspis Henderson 1888 Pylopagurus Milne-Edwards & Bouvier

1893

Xylopagurus Milne-Edwards 1880 Ostraconotus Milne-Edwards 1880 Orthopagurus Stevens 1927 Of these, Paguropsis, Tylaspis. and Ostraconotus are monotypic and none have been reported from the Pacific Ocean, From the Eastern Pacific there have been reported to date, only a single specimen of Cancellus, nine species of Pylopagurus, two species of Orthopagurus, and one species of Xylopagurus,

ACKHOWIiEDGEMERTS

The writer wishes to express his appreciation to Captain Allan Hancock and the Director of Research of the Allan, Hancock Foundation for the great privilege of using the collections and facilities of the Foundation for this study, and to Dr. John S. Garth for his guidance and for assistance in preparing this manuscript.

(4 )

GENERAL OBJECTIVE

The knowledge of any group of animals is usually founded upon taxonomic studies which establish morphological boundaries for genera and species, and make possible the identification of the animals for further, more detailed studies, such as of the physiology, development, and ecology of the group.

The general purpose of this paper is to thus

lay the groundwork for a greater understanding of these anomalous pagurids; to facilitate their accurate identifica­ tion; and to report fully their occurrence off the Pacific coast.

SPECIFIC OBJECTIVES

I.

The description of new f o r m s . —

The extensive

nature of the Hancock collections in areas never before thoroughly collected has resulted in the discovery and de­ scription of one species and one sub-species. II.

The redescriptioh of all Pacific species. —

original descriptions were written by no less than eight different authors, some of them many years ago.

Consequently,

there is no uniformity of either style or characters describ­ ed, which makes the identification of similar species very (5 )

The

6

difficult.

To insure the description of all significant

characters, and a parallel style, which would facilitate comparison of characters, the following outline for specific descriptions was developed: 1.

Ghelipeds a. Major cheliped (1) merus (2) carpus (3) manus

2.

Carapace a, Precervical portion b. Postcervical portion

3.

Eyes a. Stalk b. Cornea c. Scales

4.

Antennae a. Acicle b. Peduncle c. Elagellum

5.

Antennuies a. Peduncle b. Flagellum

6.

Pereiopods a . Ambulatory legs (1) merus (2) carpus (3) propodus (4) dactylus b. Fourth and fifth legs

7.

Abdomen a. Appendages b. Terga

8.

Tail fan a. Telson b, Uropods

III.

The discovery of new specific characters. —

On

7

the basis that any given species generally occupies a defi­ nite ecological niche, particular attention has been given to describing heretofore neglected parts that are especially modified to adapt the animal to its environment and which would furnish characters of specific value in classification, IV. —

The illustration of previously unfigured species.

With the exception of Faxon's work (1895) the Pacific

species have never been adequately figured.

Thejr are here

illustrated, as Barnard (1950) states for his figures, "... without artistic pretensions,

... intended to indicate

the features which a student should look for when seeking to identify specimens, and which cannot always be appreciated from a verbal description, however explicit." V.

The reporting of the geographic and bathymetric

distribution. —

The large number of collecting stations

disclosed several significant extensions of the reported range of certain species.

DEFINITION OF TERMS

A few terms not always used in other groups of Crus­ tacea have been employed and should be first defined. Carcinoecium —

The "dwelling," such as a gastropod

shell, worm tube, or sponge acquired by pagurids to protect their unarmored abdomens.

8

Rasp —

A well defined patch of imbricating corneous

granules borne on the uropodal blades, the fourth, and fifth thoracic legs; by which the pagurid clings to its carcinoecium. Front -- The anterior margin of the carapace, the "rostrum" in some Brachyura and Macrura. Acicle —

The mobile scale borne on the dorsal surface

of the second peduncular joint of the antennae. Ophthalmic scale —

A prominent dorsal plate over the

coxal articulation of the eyestalks. Caudal shield —

Used by the writer for bouclier or

"buckler" used by Milne-Sdwards to apply to the calcified ultimate and penultimate abdominal terga of Xylopagurus which serves in this genus as a posterior operculum to the tubular carcinoecium. The designation "Baja California" has been restricted to localities on the west, or Pacific Ocean, coast of the peninsula.

Localities from the east coast of the peninsula

are all designated "Gulf of California," although the locality may be within the political boundaries of the State of Baja California.

9

STATUS OF SUB-FAMILIES

The names of the sub-families to which these straightline genera belong are a point of controversy dating from 1396•

No analysis has been published although Stevens (per­

sonal communication) states that she intends to publish a resume of the case* Since some authors persist in using nomenclature which is at variance with an Opinion of the International Commission on Zoological Nomenclature, a review of the case is presented here. The family Paguridae naturally falls into two groups, generally designated as sub-families.

One has the left chel-

iped the larger and the third pair of maxillipeds approximated (Sinistrals), the other has the right cheliped the larger and the third pair of maxillipeds separated at the bases by a broad sternum (Dextrals).

At the present time the same name,

Pagurinae, is applied to both these sub-families by differing groups of investigators. This unfortunate situation is due to an erroneous ap­ plication of names when the group was first divided by Brandt (1851) into Pagurus and Eupagurus. Since the type of the genus, Pagurus bernhardus is a Dextral, the name Pagurus should have remained with the dextral group.

However, this

name;was applied to the Sinistrals and this arrangement was

10

continued by subsequent workers*

A step by step chronological

explanation of the noraenclatural changes is here outlined and diagrammed on the following page. 1.

1798.

Genus Pagurus erected by Fabricius to in­

clude both Sinistrals and Dextrals. 2.

1810.

Pagurus bernhardus Linnaeus designated as

genotype by Latreille. 3.

1851.

Genus split into subgenera Pagurus and

Eupagurus by Brandt, with Pagurus being assigned to the group (Sinistrals) which did not contain the genotype. 4.

1852.

Pagurus of Fabricius independently divided

by Dana into two genera, Pagurus and Bernhardus« also assign­ ing the name Pagurus to the Sinistrals and putting the type in his genus Bernhardus. 5.

1859.

Eupagurus and Pagurus of Brandt raised to

generic rank by Stimpson. 6.

1875.

Dardanus split off from Pagurus of Brandt

1877.

Kossman showed that Dardanus is not dis­

by Paulson. 7.

tinct from Pagurus Brandt. 8.

1896.

Benedict ealled attention to the fact that

the name Pagurus, which had been applied to the Sinistrals, must remain with the Dextrals because the genotype belonged to this latter group.

However, he proposed no name for the

11

Sinistrals to replace Pagurus transferred to the Dextrals, in effect leaving the group without a name for a period of six years. 9.

1903.

Benedict proposed the name Pagurias for

the Sinistrals. 10.

1902.

Rathbun pointed out that Paulson’s name

Dardanus was valid and available for this group and had priority over Pagurias. At the time of the papers of Benedict and Rathbun (1903) on this subject, a group of European carcinologists, among whom Stebbing was a principal spokesman, maintained that Latreille’s designation of a "type" in 1810 did not constitute the designation of a genotype because he did not use the term wtype” in the sense that it later became ac­ cepted in zoological nomenclature, but merely as an illustra­ tion, or readily recognized example of the pagurids. To resolve this situation, which resulted in the ap­ plication by European workers of the name Pagurus to the sinistral forms, and by Americans to the dextral forms, Miss Rathbun submitted the case to the International Commission on Zoological Nomenclature for a decision on the validity of the designation of types by Latreille. Some time between 1908 and the first half of 1910 (the records of the Commission for this period have now been lost) the Commission adopted Opinion 11, which ruled In favor

12

DEXTRALS

SINISTRALS PAGURUS bern­ hardus

EUPAGURUS

PAGURUS

bern­ hardus

BERNHARDUS bern­ hardus

PAGURUS

EUPAGURUS bern­ hardus

DARDANUS

PAGURUS

7

EUPAGURUS bern­ hardus

8

PAGURUS bern­ hardus

PAGURIAS

DARDANUS

9

PAGURUS bern­ hardus

10

PAGURUS bern­ hardus

13

of Benedict’s contention that the type of Pagurus was Pagurus bernhardus as designated by Latreille.

This Opinion

was first published in July, 1910 (Smithsonian Publication 1938, pp. 17-18) and presumably clarified the status of the names involved.

However, the widespread use of Eupagurus

and lupagurinae after this decision continued in taxonomic papers and more general works such as "The Cambridge Natural History Series” (1923).

In 1945 this Opinion was republished

by the International Commission.

SYSTEMATIC SECTION

Sub-family DARDANINAE Buitendijk 1937 1898

Pagurinae Ortmann, Zool. Jahrb., Abt. Syst. 10, Jena.

1905

Pagurinae, Alcock, Cat. Indian Dec. Crust., Pt. 2, Fasc. 1.

1935

Pagurinae, Gordon, Ann. & Mag. Nat. Hist., 10th Ser., 16.

1937

Dardaninae Buitendijk, Temminckia II, Leiden.

1938

Pagurinae, Yap-Chiongco, Phil. J. Sci. , 6_6 (2), Manila.

1939

P agur u s -Gr up p e Melin, Svensk. Vetensk. Akad. Handl., Ser. 3, 18.

1950

Pagurinae, Barnard, Ann. S. Africa Mus. 38. (Note: While Buitendijk (1937) cites Rathbun as the

author of the name for this sub-family, the writer could find no record of the use of this name in Rathbun*s papers. Her use of the generic name would presuppose adoption of the new sub-familial name and this implication was probably the reason for crediting the name to Rathbun.

However, this,

per se, cannot be considered as the application of the name and it is not cited in the synonymy.)

Cancellus Milne-Edwards 1836 (14)

15

1836

Cancellus M.-Edw.. Ann. S c i . Nat., Zool. 6 (2), pp. 262 & 286.

1837

Cancellus M.-Edw., Hist. Nat. Crust. 2 , p. 243.

1888

Cry11opagurus Zietz, Trans. Roy. Soc. S. Austral. 1 0 . (1887), p. 298.

1893

Cancellus.Faxon,

Bull. Mus. Comp. Zool.

1895

Cancellus.Faxon,Mus. Comp.

1905

Cancellus.Alcock, Cat.

24, p. 167.

Zool. 18, p. 52.

Ind. Dec. Crust., Pt.

2 (1),

p. 76. Chelipeds similar and equal; body squat; carapace not broadened posteriorly, strongly calcified except in branchial regions; rostrum broad, not prominent; eyestalks long, slen­ der, ophthalmic scales well separated; antennal acicle well developed, flagellum short; external maxillipeds

approxi­

mated at base, endopodite of first maxilla not flagellate. Genotype: £. typus (Milne-Edwards 1836)

Cancellus tanneri Faxon 1893

Cancellus tanneri Faxon, Bull. Mus. Comp. Zool. 24, p. 167.

1895

Cancellus tanneri Faxon, Mem. Mus. Comp. Zool. 18, p. 52. Type: Male holotype, dredged in 66 fathoms by the

Albatross near Cocos Island, Costa Rica, Albatross station

16

no. 3368, in the Museum of Comparative Zoology, Harvard Uni­ versity.

(Faxon 1895).

Description: Chelipeds equal, short, stout, symmetri­ cal; upper surface of propodus and anterior part of carpus flattened to form operculum when chelipeds meet; medial mar­ gin of hand a raised crest cut into close-spaced quadrangular lobes, free margin of each lohe irregularly toothed, superior and lateral faces of propodus rugose; fingers short and thick, furnished with large, horny, black nails meeting only at tips, commissural faces armed with coarse teeth, dactyl strongly curved, surface tuberculose. Precervical portion of carapace calcified, about as broad as long; median point a rudimentary triangle, lateral points as large as median, broadly rounded; postcervical por­ tion with cardiac region calcified, and two narrow calcified areas on branchial region near cervical groove. Eyestalks slender, cylindrical, slightly turned in­ ward, somewhat shorter than anterior portion of carapace; cornea not dilated, wider than stalk, dark brown; ophthalmic scales triangular, short, acute, produced to form a prominent angle on external side of proximal end. Antennal acicle short, triangular, ending in small distal spine, external margin armed with three, internal margin*, with two, spinous teeth; peduncle about one-half as

17

long as eyestalk; flagellum short, exceeding eye stalk by one-half its length. Face of distal end of propodus and dactyl of first pair of ambulatory legs, as of chelipeds, forming opercular facet; facets margined with denticulated lobes, setose, gran­ ular; dactylus about as long as propodus, tipped with horny claw. Abdomen very short and obese, longitudinally and trans­ versely convex, soft, covered with short velvety down except for last three segments; abdomen as whole not quite bilateral­ ly symmetrical, right side more swollen than left, imparting slight twist to left. Telson broader than long, sides regularly rounded, terminal margin nearly straight. Distribution and Remarks: The one specimen taken in a cavity in a piece of coral by the Albatross is the only record of this species, and the only record of the genus from the Pacific.

Sub-family PAGURINAE Buitendijk 1937 1898

Eupagurinae Ortmann, Zool. Jahrb. Abt. Syst. 10, Jena.

1905

Eupagurinae, Alcock, Cat. Ind. Dec. Crust. Pt. 2, Fasc. 1.

1935

Eupagurinae, Gordon, Ann. & Mag. Nat. Hist. 10th Ser., 16.

18

1937

Pagurinae Buitendijk, Temminekia II, Leiden.

1938

Eupagurinae, Yap-Chiongco, Phil. J. S c i .

1939

Pagurus-Gruppe Melin, Svensk. Vetensk. Akad. Handl. Ser.

§6_ (2),

Manila.

3, 18. 1950

Eupagurinae, Barnard, Ann. S. African Mus. 38;

Orthopagurus Stevens 1927 1900

Pagurus (in part), Holmes, Occas. Papers Cal. Acad. Sci. 7, p. 145.

1904

Pagurus (in part), Rathbun, Harriman Alask. Exped. 1 0 , p. 160.

1921

Pylopagurus (in part), Schmitt, U. Cal. Publ. Zool. 23, p. 144.

1925

Pylopagurus (in part), Stevens, Publ. Puget Sound Biol. Sta. 3, p. 297.

1927

Orthopagurus Stevens, Publ. Pugent Sound Biol. Sta. 5, p. 245.

1930

Orthopagurus t Hart, Canad. Field Hat. 44 (5), p. 104. Chelipeds dissimilar and unequal, the right much

larger,

Fourth pair of legs subchelate.

External maxilli­

peds widely separated at base; exopodite of all three pairs flagellate; endopodite of first maxilla not flagellate, but furnished

with a strong sharp seta.

Abdomen not spirally

coiled, but flexed; no paired appendages except uropods in either sex.

Tels^n and uropods very, nearly symmetrical.

19

Gills phyllobranchiae, eleven on either side. Genotype: Not designated.

Key to the Pacific species of Orthopagurus 1.

Large hand distally widened, base narrow, transversely and longitudinally convex, distal portion declivate with edges upturned; lateral teeth of front rounded. (). minimus

2.

Large hand nearly uniform in width, flattened

or slight­

ly convex; lateral teeth angular, practically obsolete. 0. schmitti

Orthopagurus schmitti (Stevens) 1925

Pylopagurus schmitti Stevens, Publ. Puget Sound Biol. Sta. 3,- pp. 247-252, figs. 19-22.

1927

Orthopagurus schmitti Stevens, Publ. Puget Sound Biol. Sta. 5, pp. 249-252, figs. 2-4.

1930

Orthopagurus schmitti, Hart, Ganad. Field Nat. 44, p. 104. Type: male holotype, from Point Caution, Puget Sound,

deposited in U. S. N. M.

(Stevens 1925).

Description: Chelipeds unequal, dissimilar, right vastly larger, merus compressed; carpus distally widened, upper surface with anteriorly inclined spines; hand oblong,

2°

of nearly uniform width, inner margin of palm armed with spines similar to those of carpus, upper surface slightly convex, hut appearing quite flattened; fixed finger broad, outer edge with anteriorly inclined spines, dactyl more nearly uniform in width* Minor cheliped stout, reaching nearly as far as major hand; merus smooth, compressed, superior margin crested with longitudinal line of plumose setae; carpus slightly shorter than merus, superior surface rounded, bearing strong anter­ iorly curved spines and extremely long coarse setae; hand slightly longer than carpus, palm setose, with pointed gran­ ules, medial margin rounding smoothly into inner face, lateral margin distinct ridge of pointed granules; pollex flattened, approximately as long as palm, dactyl more convex at base. Precervical portion of carapace rugose, well calcified, approximately as wide as long; median point triangular, acute, three times as wide at base as high; lateral points angular, greatly reduced, barely reaching base of median point, and armed at apex with minute conical spines. Postcervical portion pilose, with tufted plumose setae. Eyestalks slender, tapering; cornea not dilated be­ yond width of eyestalk; ophthalmic scales bluntly pointed, with prominent acute, subterminal spines.

21

Antennal acicle slender, acute, outward curving, barely reaching base of cornea, unarmed, but with tufts of setae; peduncle when extended exceeding length of eyes by one-half length of flattened terminal article; flagellum with scat­ tered setae. Antennular peduncle widening distally, when extended exceeding length of eyes by one-third the length of terminal article; superior flagellum of about fifteen simulations, ter­ minal segments longer than proximal, drawing distal half into a filiform process. Ambulatory legs equally developed on both sides, merus much flattened, superior and inferior borders with single line of tufts of compound setae; carpus slightly more than one-half length of merus, superior surface with coarse simple setae; propodus longer, also with coarse setae on superior and also inferior surface; curving dactyl approximately as long as propodus, spinulous below, and tipped with a curved corneous claw; fourth pair of legs barely reaching merus of third pair, subcheliform, margined with plumose setae; fifth pair minutely chelate, with rasp on outer face of propodus and minute dactyl. Abdomen uncoiled, membranous, terga symmetrical, not in contact except in caudal shield, appendages biramous, four in number, present on left side only; caudal shield

22

roughly quadrangular, rugose, calcified, although flexible, margins rounded, entire, suture between terga complete and flexible, fringe of setae at posterolateral corners and two tufts in slight notches on terminal margin. fail fan symmetrical, uropods well calcified, both bases and blades, granules of rasp pointed and slanting for­ ward; telsen roughly quadrangular, margins entire except for few minute pointed teeth on terminal margin, fringed terminal­ ly and laterally with setae. Distribution: This species has been reported only from Puget Sound.

The Hancock collections do not contain any speci

mens from this area and the species is not represented. Remarks: This description, except for that of the major cheliped, was based upon a single female specimen collected near Friday Harbor, Washington, by Dr. John L. Mohr.

The

specimen, in a tube of the polychaete, Sabellaria cementarium Moore, was parasitized by two female copepods and lacked the major cheliped.'

The description of the missing part was

taken from the description by Stevens (1927).

Orthopagurus minimus (Holmes) Pagurus minimus Holmes, Occas. Papers Gal. Acad, Sci. 7., p. 145. 1904

Pagurus minimus. Rathbun, Harriman Alaska Exped. 10 p. 160.

23

1921

Pylopagurus minimus. Schmitt, U. Cal. Publ. Zool. 23, p. 144, PI. 16.

1927

Qrthopagurus minimus, Stevens, Publ. Puget Sound Biol. Sta. 5, pp. 247-249, fig. 1. Type:

The female holotype from off San Diego, in 30

fathoms, is deposited in the collections of the University of California (Holmes 1900). Description:

Ghelipeds unequal, dissimilar, right

vastly larger, somewhat pubescent.

Merus smooth, compressed,

with spinule on dorsal peak of distal margin; rounded superior surface of carpus with corneous-tipped, anteriorly hooked spines in longitudinal rows; hand oblong, widening distally to point beyond base of fingers, basal angle longitudinally and transversely convex, armed with spines similar to those on carpus; face of hand, including fingers, margined with a raised, evenly denticulate ridge, making opercular face transversely concave, but longitudinally flat;

surface with­

in margins smooth, polished, with setae only in a few fas­ cicles near commissural edges of fingers. Minor cheliped reaching slightly beyond distal end of carpus of major cheliped, merus smooth, compressed; carpus compressed, superior surface with forward hooked spines and coarse setae; hand setose, narrow, rounded, upper surface oblique, with two rows of small spines; fingers longer than palm, inner surfaces excavated, leaving narrow, sharp cutting

24: ridge. Precervical portion of carapace about as wide as long, smooth, polished; median, projection triangular, acute, only one-half as long as wide at base; lateral projections rounded, barely reaching base of median projection; membranous postcervical portion shorter than precervical, Eyestalks stout, cylindrical, length slightly more than distance between lateral points of front; cornea not expanded wider than stalk; ophthalmic scales bluntly pointed, with sharp subterminal spines projecting prominently. Slender, curved antennal acicle slightly setose, reaching base of cornea; peduncle when extended exceeding eyes by one-half the length of slender terminal artiele; flagellum setose, exceeding reach of major hand. Antennular peduncle stocky, exceeding eyes by approx­ imately one-half length of terminal article, superior fla­ gellum of approximately fifteen annulations, distal articles longer than proximal. Pereiopods slender, rather compressed, equally devel­ oped on both sides; carpus two-thirds length of propodus, bearing prominent spine on superodistal margin; propodus rugose, slightly shorter than dactylus; dactylus curving, tipped with horny claw, and bearing row of spines on inferior surface. Fourth pair of thoracic legs subchelate, short, reach­ ing only to base of meropodite of third pair; fifth pair

25

minutely cheliform, bearing rasp on outer surface of propodus and on minute dactylus. Abdomen straight, longer than carapace; appendages biramous, on left side only, three in males, four in females; terga symmetrical, not in contact except in caudal shield; caudal shield roughly quadrangular, rugose, well calcified, anterior and lateral margins of anterior tergum a swollen, rounded ridge, suture between terga present as deep sulcus, though completely calcified in older specimens, posterior tergum with fringe of setae on posterolateral corners, and two tufts on terminal margin. Tail fan essentially symmetrical, uropods short, heavy, shorter than length of caudal shield; telson rounded, terminal margin bearing pair of curved spines on each side, many small denticulations between pairs. Distribution: Skidegate, Queen Charlotte Sound, Brit­ ish Columbia; San Francisco Bay, Laguna Beach, and San Diego, California: 15-55 fathoms.

(Schmitt 1921).

Specimens in the Hancock collections are from Santa Cruz-Island, Anacapa Island, Santa Bosa Island, Redondo Beach, Portuguese Point, Long Beach, Newport Channel, Santa Catalina Island, Laguna Beach, California; and San Benito Islands, Baja California.

The complete list of stations

at which this species was taken is as follows:

881-38 988-39 995-39 1005-39 1008-39 1130-40 1131-40

1139-40 1143-40 1160-40 1224-41 1267-41 1280-41 1283-41

1284-41 1298-41 1303-41 1362-41 1391-41 1407-41 1412-41

1414-41 1418-41 1419-41 1422-41 1902-50 1937-50

The bathymetric range was from the intertidal zone (at two different stations) to 250 fathoms. This report of the species from San Benito Islands at 28

1 6 T 17” N. Latitude, and 115° 3 2 1 54” W. Longitude con­

stitutes the first report of its occurrence in Mexican waters. Remarks: The most common carcinoecia were the tubes of the Polychaete, Protula s p .. and a tubular bryozoan colony, Antropora tincta (Hastings), although a few small specimens were taken in coiled gastropod shells,

Pylopagurus Milne-Edwards & Bouvier 1893 1880

Eupagurus (in part), M.-Edw. , Bull. Mus. Comp. Zool. 8, p. 41.

1882

Eupagurus (in part), Studer, Abhandl. K5n. Akad. Wissensch. Berlin 1882, p. 26, fi-g. 13a, b, c.

1892

Eupagurus (in part), Benedict, Proc. USNM 15, pp. 24-25.

1893

Pylopagurus M.-Edw. & Bouvier, Mem. Mus. Comp. Zool. 1 4 . p. 74.

1898

Eupagurus (in part), Bouvier, Bull. Mus. Hist. Nat.

27

Paris 8, p. 382. 1900

Pagurus (in part), Holmes, Occas. Pap. Cal. Acad. S c i . 2, p. 145.

1905

Pylopagurus. Alcock, Gat. Ind. Dec. Crust. Pt. 2 (1), p . 25.

1918

Pylopagurus, Hay & Shore, Bull. U. S. Fish Comm. 5 5 , p. 413.

1925

Pylopagurus, Stevens, Publ. Puget Sound Biol. Sta. 3, p. 297.

1928

Pylopagurus, Boone, Bull. Bing. Ocean. Coll. 1 (2), p. 71.

1937

Pylopagurus. Glassell, Zoologies 22 (3), pp. 253-256.

1939

Pylopagurus, Chace, Mem. Soc. Cubana Hist. Mat. 15, p. 48.

1939

Pylopagurus. Melin, Svensk. Yetensk. Akad. Handl. Ser. 3 18, p. 20.

1950

Pylopagurus. Barnard, Ann-. S. Afr. Mus. 38, p. 416. Chelipeds dissimilar and unequal, the right much

larger, highly developed as more or less discoidal operculum. Fourth pair of thoracic legs subchelate. External m a x i H i peds widely separated at base, expodite of all three pairs flagellate.

Abdomen not spirally coiled, straight or merely

flexed, paired abdominal appendages present on first somite of female only; vasa deferentia of male not extruded. Genotype: Mot designated.

£8

Key to the Eastern Pacific species of Pylopagurus Carpus of major cheliped with three or less teeth on inner margin of dorsal surface. A.

Telson with strong curved

shaped notch, in terminal margin, teeth at each edge of notch; mar­

gins of opercular face of hand a low sub-serrate ridge................................... P_^ holme si B.

Telson simple

semioval plate with entire margins,

margins of opercular face of large hand with dis­ tinct denticulations. 1.

Carpus of major cheliped with three teeth on inner margin of dorsal surface. a.

Outer margin of major hand a low granu­ late ridge

b.

P. spinicarpus

Outer margin of major hand with large evenly spaced teeth tipped with inwardly directed corneous spinules.P. glasselli n.sp.

£.

Carpus of major cheliped with two teeth on inner margin of dorsal surface. a.

Lateral points of front rounded, inner margin of minor hand unarmed..P. guatemoci

b.

Lateral points of front acute, inner mar­ gin of minor hand with row of sharp spines........................ P. coronatus

29

II

Carpus of major cheliped with more than three teeth on inner margin of dorsal surface. A.

Telson grossly asymmetrical, palm of hands ornamen­ ted with large conical tubercles with radiating peripheral processes................... P. hirtimanus

B.

Telson essentially symmetrical, palm set with micro­ scopic granule s . 1.

Denticulations on terminal margin of telson re­ stricted to sides of notch....... P. cervicornis

2.

Denticulations of telson not restricted to notch, but extending across terminal margin. a.

Major cheliped longer than rest of body, granules of palm tipped with vertical corneous spinules...... .../.. P. longimanus

b.

Major cheliped shorter than rest of body, granules of palm tipped by anteriorly directed corneous spinules....... P. varians

Pylopagurus holmesi Schmitt 1921

Pylopagurus holmesi Schmitt, U. Cal. Publ. Zool 23, pp. 144-145, figs. 94a, b. Type : Male holotype, U. S. N. M. catalogue number

53330, from Santa Catalina Island, California. 1921).

(Schmitt

30

Description: Chelipeds unequal, dissimilar, the right vastly larger; discoidal upper surface completely margined by raised, finely incised denticulate ridge, separating dis­ coidal surface posteriorly from short, transversely and longitudinally convex proximal portion; widest portion at base of broad flattened fingers; carpus trigonal with stout acute spine at anteromedial eorner, surface covered with distinct, pointed, forward curved granules; merus tri­ gonal, only slightly exceeding length of eyes, lower antero­ lateral corner with stout spine* Minor cheliped very small, less than one-half width of right, lateral margin of palm slight, finely denticulate ridge, fingers gaping at base, with fascicles of setae on outer edges; carpus crested with many sharp spines;* Precervical portion of carapace smooth, polished, slightly longer than wide, median point narrow, acute, twice as long as width of base; lateral projections rounded, reaching only slightly beyond base of median point; postcervical portion not calcified, posterior border with slight rounded indentation* Eyestalks short, stout, compressed; corneas dilated; eye scales triangular, longitudinally convex, apices slight­ ly rounded, furnished with stout, acute, subterminal spines* Antennal acicle slender, smooth margined, acute,

31

curving outward, slightly shorter than eyes, antennal peduncles when extended slightly exceeding eyes, flagella slightly setose and reaching less than length of major cheliped; antennular peduncles longer than eyes, ventral flagellum three-fourths as long as dorsal flagellum. Pereiopods on left side as long as right, reaching base of fingers of major hand; carpus and propodus crested with forward hooked, pointed spines; dactyl spinulose, slightly longer than propodus, and tipped with sharp corn­ eous claw. Fourth pair of thoracic legs subchelate, rasp restric ted to distal margin, not developed on outer face of hand; fifth pair minutely chelate, rasp developed on outer sur­ face of propodus and fingers. Abdomen straight, membranous, longer than thorax, terga not present except in poorly calcified caudal shield, which is quadrangular in outline, with corners rounded, suture flexible; appendages narrow, flattened blades, on left side only. Telson symmetrical, rather poorly calcified, smooth, outline almost half-circle except for prominent notch in terminal margin, strong, downward curving, flattened tooth at each end of notch, setae and smaller denticles along sides toward apex; uropodal peduncles short, heavy, anter­ ior pair of blades over twice length of posterior pair,

32

both sparsely setose along anterior and posterior margins. Distribution:

Prom Santa Catalina Island and San

Pedro to San Diego, California; 10 to 30 fathoms.

(Schmitt

1921). Specimens in the Hancock collection are from San Miguel Island, Santa Cruz Island, Santa Barbara Island, Santa Catalina Island, San Clemente Island, Tanner and Cortes Banks, California; San Benito Islands and Cedros Island, Baja California; Inner Gorda Bank, Coronados ^sland, Natividad Island, Angeles Bay, San Pedro Nolaseo Island, Angel de la Guardia Island, Lobos Point, Sonora and Consag Rock, Gulf of California, Mexico. The bathymetric range was from 1 to 250 fathoms. This species was taken at the following Hancock stations: 523-36 539-36 541-36 546-36 725-37 735-37 882-38 975-39 979-39 1009-39

1010-39 1012-39 1023-39 1024-39 1035-40 1054-40 1057-40 1068-40 1080-40 1084-40

1119-40 1147-40 1251-41 1253-41 1258-41 1278-41 1298-41 1322-41 1330-41 1336-41

1338-41 1341-41 1348-41 1418-41 1419-41 1422-41 1919-49 1920-49 1922-49 1927-49

The San Miguel Island record at 34°056 20" N. Lat­ itude and 120° 80* 40" W. Longitude represents a slight northward extension of range for the species.

The south­

ward records to the tip of Baja California and thence north

ward almost to the head of the Gulf of California constitute a very considerable extension of the known range of this species, and indicates an unique geographic distribution. The bathymetric range is also quite large, from one fathom at Angeles Bay, Baja California, to 250 fathoms off Santa Catalina ^sland, California. Discussion:

The great majority of the specimens

examined had the major cheliped considerably more elongate in proportion to its width than the type as described and figured by Sshmitt.

The typical form seems to represent

one extreme in a series rdnging from a rather short cheli­ ped and an almost circular outline for the opercular face, to a very elongate cheliped with a spatulate opercular sur­ face . The discoidal hand evidently is the result of isogonic growth and the expansion of the manus takes place at an equal rate in all directions.

In older specimens, after

maximum size is attained, further laying down of calcium carbonate is accomplished by building up the margins of the hand, resulting in a very high ridge around the margin and imparting a very concave surface to the hand, although the proportions remain unchanged. The spatulate hand results from heterogonic growth of the major cheliped and increments of growth seem to be added predominately distally, with a resultant elongation

34

of the whole appendage, but the more distal articles, i. e. manus and carpus, being even more disproportionate to their homologues in the typical form.

In this type of growth the

proportions of an individual do not remain the same through­ out its life, each molt stage being reflected by an increase in length in proportion to width. The end result of this type of growth results in an animal which differs quite markedly in general proportions from the typical form.

(Compare Plates 1 and 2.)

This form

is found only in the Gulf of California to date, and in every case it was found in the ehitinous cylindrical tubes of the polychaete, Hyalinoecia .iuvenalis Moore, while the forms which closely resemble the type were taken in Dentaliuxn shells.

This form should be considered as being a sub­

species distinct from the type (ecologically isolated), and is described below.

However, since the intergradation is so

complete, the demarcation point between this form and the typical form is necessarily quite arbitrary. Sexual dimorphism is involved to some degree in this phenomenon, the males exhibiting heterogonic growth to a greater extent than do the females as indicated by a com­ parison of the ratio of width to length of various articles in the major chelipeds of a series of topotypes,

(discoidal),

and— a— serres~from the~Culf of Calrfornia^~(~spatxQratre~)".

How-

ever, in such a small sample there is always the possibility

35

that the females represented younger; therefore more typical, stages, since they were considerably smaller.

Pylop agurus holme si s . s p . longicarpus n . s . s p . Type: Male holotype; five male and five female paratypes, station number 1057-40 from off Puerto Refugio, Angel de la Guardia Island, Gulf of California, dredged 29 January 1940 by the Yelero III in 51-56 fathoms. Diagnosis: Major part of upper surface of large hand spatulate, over twice as long as wide, widest portion dis­ tal to base of fingers; carpus greatly elongate, over twice as long as wide. Description: Specific characters agreeing with those of holotype of the species, differing only in general pro­ portions.

Major hand three times as long as wide, widest

portion just distal to base of dactyl, upper surface bounded by raised, finely denticulate margins, posterior margin low, poorly defining opercular surface from narrow basal portion; opercular surface convex proximally, becoming concave at point near base of dactyl, hand longitudinally convex giv­ ing appearance of being bent downward; carpus elongate, over twice as long as widest portion, upper

surface rounded,

covered with fine, non-confluent granules; merus exceeding eyestalks by two-thirds its total length. Measurements: Total length (rostral point to tip of

36

abdomen) 33 mm.; length of carapace 4.3 mm.; length of major manus 5.9 mm.; width of major manus 2.3 mm.; length of carpus 4.2 mm.; width of carpus 1.7 mm.; length of minor manus 2.4 m m . ; width of minor manus 1 m m . ; length of dactyl second thoracic leg 3.6 mm.; length of propodus second thoracic leg 2.9 mm. Distribution: Specimens of P. holme si with the char­ acteristic proportions of this sub-species were taken in the G-ulf of California off Puerto Refugio, Angel de la Guardia Island, at Puerto Refugio, and off Consag Rock at the fol­ lowing stations: 541-36 1057-40 1068-40 The bathymetric range was from 24 to 60 fathoms.

Pylopagurus guatemoci Glassell 1937

Pylopagurus guatemoci Glassell, Zoologica 22 f (3) p. 254. Type: Male holotype, New York Zoological Society

Department of Tropical Research catalogue number 36801," from five miles west of San Jose Point, Pacific side of Baja California in 45 fathoms.

(Glassell 1937).

Description: Chelipeds dissimilar, unequal, right vastly larger, merus smooth, trigonal, as deep as wide,

37

inferomedial margin with deep narrow indentation to receive ischium; carpus greatly widened distally, superomedial bor­ der armed with two prominent forward-curving spines, one overhanging anterior margin, the other medial; upper surface smooth, lightly setose, rounding gradually to the inferolateral margin; manus discoidal; face four-fifths as wide as long, almost completely surrounded by upturned denticu­ late margin; proximal margin prominent, teeth irregular in size, tipped with corneous spines, some teeth double, some turned inward; teeth on fingers a continuation of those of palm but diminishing in size and inclined outward instead of vertical; face of hand set with microscopic low rounded granules bearing high, slender, corneous spines. Minor cheliped extending to base of fingers of major hand; carpus bicristate, medial row of spines smaller, hand depressed, outer margin of row of spines extending onto pollex, palm with medial row of small spines, medial margin unarmed and slightly setose. Precervical portion of carapace as broad as long, strongly transversely convex, smooth, polished; medial pro­ jection a broad-based triangle, three times as wide at base as high, tipped with minute spinule; lateral projec­ tions rounded but tipped with minute spinule; postcervical portion naked, membranous. Eyestalks cylindrical, slightly constricted in mid-

38

die, equal in length to width of front; cornea very slightly dilated; ophthalmic scales longitudinally convex, bluntly rounded with very prominent, wide-based, acute, subterminal spine. Antennal acicle slender, curving, acute, reaching just beyond corneal base, margins entire, medial margin setose; peduncle when extended exceeding eyes by one-third length of terminal article; flagellum with scattered setae. Antennular peduncle when extended exceeding corneal base by full length of terminal article; dorsal flagellum densely setose beneath; ventral flagellum small, of five articles with single terminal seta. Ambulatory legs equally developed on both sides; mer­ us smooth compressed,

superior and inferior margins with

line of tufted setae; carpus has single, small, hooked spine medially on superior surface; propodus almost one-fourth longer than dactyl; dactyl spinulous on superior and infer­ ior margins, setose, tipped with sharp, curved, horny claw. Fourth pair of thoracic legs subchelate, rasp re­ stricted to small area on face of propodus; fifth pair lon­ ger than fourth, rasp covering one-half of propodus and the minute dactyl and pollex. Abdomen short, obese, terga not present except in caudal shield; anterior tergum separate, larger, smooth, anterolateral corners rounded; posterior tergum with poster-

39

olateral corners produced into bluntly triangular lobes equipped with long setae. Telson symmetrical, semioval, smooth, margins en­ tire; uropodal blades equally developed on both sides, rasp covering narrow crescentic area on upper distal face, pos­ terior blade reduced, barely exceeding base of anterior blade, rasp covering almost all upper surface. Distribution: Previously known only from the type locality near San Jose Point, Baja California, in 45 fath­ oms.

(Glassell 1937). Specimens in the Hancock collections are from Point

Hueneme, Santa Cruz Island, Santa Rosa Island, Seal Beach, Santa Barbara Island, Santa Catalina ^sland, San Clemente Island, and San Diego, California; Cortes Bank, Guadalupe Island, and Cedros Island, Baja California and east of Angel de la Guardia, Gulf of California, Mexico. The complete list of stations at which this species was taken is as follows: 534-36 984-39 1012-39 1018-39 1023-39 1158-40

1240-41 1253-41 1264-41 1274-41 1298-41 1342-41

1354-41 1374-41 1391-41 1392-41 1418-41 1624-48

1920-49 1922-49 1927-49

The bathymetric range was from 11 to 150 fathoms. The Hueneme locality at 34° 05’ 30” N. Latitude 119° 02* 40” W. Longitude now represents the northernmost

40

report of the occurrence of the species and the Cedros Island station at 28° 0 5 f 50" N. Latitude 115° 31* 00" W. Longitude the southernmost report, and the Angel de la Guardia Island locality is the only report of this species from the Gulf of California. Remarks: Two female specimens were without the paired abdominal appendages characteristic of the genus.

Both were

heavily infected with (what the writer believes to be) rhizocephalan parasites and the lack of these appendages is there­ fore presumed to be the result of parasitic castration with suppression of secondary sexual characteristics.

Pylopagurus glasselli sp. nov. Type; Male holotype dredged by the Yelero III 2 March 1936 at station 534-36 off San Francisquito Bay, Gulf of California, in 125 fathoms. Diagnosis: Merus of major cheliped trigonal, inner margin of carpus with three spines, two medial and one dis­ tal; opercular surface of hand entirely margined by regularly spaced inward-curving spines with sharp corneous tips; med­ ian projection angular, apex sharply truncate, lateral points rounded, almost obsolete. Description: Chelipeds dissimilar, unequal, right vastly larger, with merus trigonal, upper surface setose;

41

carpus narrow proximally, widening evenly to manus, medial margin bearing tbree distinct, forward-curving spines, two medially and one distally, superior surface lightly setose; opercular surface three-fifths as wide as long, widest point just distal to base of fingers, completely margined by evenly spaced spines with sharp corneous tips directed inward, separated by rounded sinuses, opercular face micro­ scopically set with granules tipped with corneous spinules; fingers broad, having line of tufted setae bordering cutting edges• Minor cheliped reaching base of fingers of major hand; carpus rugose, with coarse setae, inner margin armed with two minute spines medially, and large distal spine partially cleft, leaving two points on single base; outer margin of hand marked by row of small spines reaching to base of pollex, large spine supported by a

ridge on medio-

proximal margin; dactyl longer than palm, setose. Anterior portion of carapace not quite as broad as long, transversely convex, slightly rugose, and bearing a few tufts of setae, median point angular, apex sharply truncate, lateral points rounded, almost obsolescent; posterior portion membranous, slightly setose on branchial regions. Eyestalks stout, terete, constricted in middle,

4E

slightly setose on superior surface; cornea dilated beyond width of eyestalk; ophthalmic scales longitudinally convex, triangular, margins entire, with prominent subterminal spine. Antennal acicle slender, outward-curving, pointed, reaching middle of cornea; peduncle when extended exceeding eyes by two-thirds the length of the cylindrical terminal article; flagellum setose. Antennular peduncle when extended exceeding length of eyes by full length of terminal articles; superior fla­ gellum of about eighteen annulations, densely setose beneath, inferior flagellum almost equal in length to superior. Ambulatory legs slightly longer on right side, slightly compressed, setose and with margins unarmed ex­ cept for spinules on lower margin of dactyli, propodus equal in length to the related dactyl. Fourth pair of thoracic legs subchelate, rasp on propodus only; fifth pair minutely chelate. Abdomen short, membranous, terga not present except in well calcified caudal shield, anterior tergum transverse­ ly and longitudinally convex, slightly setose, rough, anter­ olateral corners rounded off, sulcus deep and flexible, posterior tergum smaller, with tufted setae on postero­ lateral corners and two tufts on terminal margin. Telson a symmetrical, simple calcareous plate, semi-

43

oval in outline with margins entire; uropods slightly larger on left side. Measurements: Total length (rostral point to tip of abdomen) 7 mm.; length of carapace 2.75 mm.; length of pre­ cervical region 1.75 mm.; width of precervical portion 1.50 mm.; length of major manus 3 mm.; width of major manus 1.75 mm.; length of dactyl 1 mm; length of carpus 2 mm.; length of minor manus 1.25 mm.; width of minor manus 0.75 mm.; length of propodus first ambulatory leg 8.5 mm;; length of dactyl first ambulatory leg 8.5 mm.; length of caudal shield 1 mm.; width of caudal shield 0.75 mm. Distribution: Known only from the type locality, off San Francisquito Bay, Gulf of California. Discussion: This species is closely related to P. guatemoci, but may be distinguished from it by the three large spines on the superior surface of the carpus (P. guatemoci having but two), the truncate rostral point, and the partially cleft spine onthe distal end of the carpus of the minor cheliped. Bemarks: The carcinoecium was a gastropod shell com­ pletely overgrown with cheilostomatous Bryozoa. The species is named for the late Steve A. Glassell who first recognized it as an undescribed species.

44

Pylopagurus coronatus (Benedict) 1892

Eupagurus coronatus Benedict, Proc. U8NM 15 (887) p. 24.

1937

Pylopagurus coronatus, Glassell, Zoologica 22 (3) p. 254. Type: Holotype in the U. S. N. M. from an unknown

locality in the Gulf of California. Description:

(Benedict 1892).

Chelipeds unequal, dissimilar, right

vastly larger, merus short, compressed, with narrow longi­ tudinal ridge on superior surface; carpus short, also crested with narrow raised ridge ending in sharp projection just short of distal margin, inner margin hearing forward hooked spine medially and similar larger spine at anterior end, overhanging distal margin; hand suboval, twice as long as carpus, opercular face completely bordered by sharp teeth separated by rounded sinuses, opercular face with unevenly spaced angular elevations. Minor cheliped very small, less than one-third the width of major hand; carpus with forward hooked spine med­ ially on inner margin, and two prominent spines side by side at anteromedial corner, hand with inner margin marked by minute sharp, forward-slanting spines, fingers about as long as palm, setose, not gaping at base. Precervical portion of carapace about as broad as long, rugose, slightly setose; median point triangular,

45

a©ute, much in advance of very acute lateral points; postcervical portion membranous, slightly setose on cardiac and intestinal areas. Eyestalks cylindrical, long, slender, much constrict­ ed in middle, cornea elongate, only slightly dilated beyond width of stalk; ophthalmic scales short, with rounded mar­ gins and prominent, acute, subterminal spine. Antennal acicle slender, outward-curving, acute, falling short of corneal base; peduncle when extended slight­ ly longer than eye; flagellum with long scattered setae. Ambulatory legs about equally developed on both sides, superior and inferior margins hairy, unarmed except for claw tipped daetyli which are spinulose on inferior margins. Fourth pair of thoracic legs extremely short, sub­ chelate v rasp restricted to terminal margin of propodus; fifth pair minutely chelate, rasp covering both fingers and laterally swollen propodus. Abdomen longer than carapace, membranous, caudal shield well calcified; anterior tergum transversely con­ vex, bearing tufts of setae, anterolateral corners rounded off, posterolateral corners produced slightly into small triangular points, suture deep and flexible; posterior ter­ gum smaller, bearing tufts of long setae on posterolateral corners and two smaller tufts on terminal margin.

46

Telson symmetrical, a simple calcareous plate, with smoothly rounded corners and entire margins; uropods sym­ metrical, heavily calcified. Distribution:

Unknown locality in the Gulf of Cali­

fornia (Benedict), and a single specimen from Arena Bank, Gulf of California, in 50 fathoms (Glassell). Specimens were taken by Hancock Expeditions at Isla Partida at station 559-36 and at San Francisquito Bay at station 634-36, both in the Gulf of California. The depths of the hauls were 45 and 125 'fathoms, respectively. Remarks: One specimen was taken in a coiled gastro­ pod shell.

Pylopagurus spinicarpus Glassell 1938

Pylopagurus spinicarpus Glassell, Allan Hancock Pap. Ixped. j5 (1), p. 1. Type: Male holotype, U. S. N. M. catalogue no. 75432,

and female paratype, from Puerto Refugio, Angel de la Guardia Island, Gulf of California, collected 4 March 1936 in 65 fathoms. Description:

Chelipeds unequal, dissimilar, right

vastly larger, merus trigonal, upper distal portion rounded, slightly setose, medial and inferior margins entire: carpus widening distally, medial margin with two forward-curving

47

medial teeth separated from larger, distal, tooth by deep rounded sinus, superior surface smooth with few large scattered setae, medial surface greatly contorted; manus longitudinally and transversely convex, medial margin of palm a raised, serrate ridge, lateral margin also raised but merely a low granulate ridge; both margins continued on to fingers; fingers and palm equal in length. Minor cheliped reaching nearly to middle of palm of major cheliped, merus compressed, smooth, slightly setose; carpus slightly shorter, widening distally with scattered coarse setae, outer margin with one medial spine, anterior margin with two spines; hand oval long, outer margin a raised low tooth ridge, inner margin obsolete, surface smooth except for raised median ridge on palm extending some distance onto pollex. Precervical portion of carapace as long as wide, transversely convex, naked, polished; median point obtuse, armed with sharp depressed spinule, lateral points as long as median, armed with spinules; postcervical portion naked, membranous. Eyestalks long, equal to width of carapace, cylin­ drical, constricted in^the middle, with several tufts of coarse setae on dorsal and medial surfaces, cornea dilated; ophthalmic scales bluntly pointed, margins entire with fringe of radiating setae, subterminal spines prominent

48

and sharp. Antennal acicle slender, outward curving, acute, reaching base of cornea; peduncle when extended exceeding length of eyes by one-third the length of cylindrical terminal article; flagellum setose. Antennular peduncle exceeding eyes by length of ter­ minal article, superior flagellum of about 17 annulations, densely setose beneath; inferior about one-half the length of superior flagellum. Ambulatory legs equally developed on both sides, slightly setose, upper margins unarmed, propodus with spinule on distal end of interior surface, dactyl spinulose beneath. Fourth pair of thoracic legs subchelate, short, rasp restricted to terminal margin of propodus; fifth pair minutely chelate, rasp oh both fingers and on swollen outer surface of propodus. Abdomen slightly longer than carapace, uncoiled, membranous, no terga visible except those of caudal shield, of which anterior is convex, with tufted setae, rounded anteriorly, posterior corners produced slightly, suture flexible, posterior smaller, posterior corners acute tri­ angular lobes. felson a smooth, symmetrical, semioval plate with entire margins; uropodal blades larger on left side, pos-

49

terior blades much reduced on both sides. Distribution:

Santa *^nez Bay and Gorda Bank, Gulf

of California, at depths from 40 to 80 fathoms (Glassell 1938). Specimens in the Hancock collections are from Angel de la Guardia Island, Gulf of California, Ladrones Island, Panama, and Gorgona Island, Colombia.

The station numbers

are: 541-36 546-36 851-38

943-39 1057-40 1058-40

The depth range was 10 to 70 fathoms.

Pylopagurus varians (Benedict) 1892

Eupagurus varians Benedict, Proc. US33M lj5 (887) p. 24.

1898

Eupagurus varians. Bouvier, Bull. Mus. Hist. Hat. 4 (8) p. 382.

1937

Pylopagurus varians. Glassell, Zoologies 22 (3) p. 253. Type: Holotype U. S. N. M. from unknown locality in

the Gulf of California.

(Benedict 1892).

Description: Chelipeds dissimilar, unequal, right vastly larger .with merus compressed, slightly crested, often produced down to angle or tubercle on inferior surface; carpus long, narrow proximally, widening toward manus, sides

50 »

■and lower surface rounded, upper surface covered with spines; hand roughly discoidal, face covered with granules constricted at base and bearing an anteriorly directed spine. Minor cheliped with carpus compressed, bicristate, inner row reduced, hand reaching past base of fingers of major hand, depressed, wide, covered with pointed granules, fingers longer than palm, widely gaping at base. Precervical portion of carapace about as broad as long, transversely convex, smooth, glabrous; median pro­ jection broadly triangular, generally with apical and b e ­ coming suddenly more acute, lateral projections angular to rounded, shorter than median, postcervical portion membran­ ous, cardiac region distinctly marked off as pentagonal plate. Eyestalks stout, terete, constricted in middle, cor­ nea dilated beyond width of stalk; ophthalmic scales bluntly triangular, longitudinally convex, with prominent acute, subterminal spine. Antennal acicle slender, outward-curving, pointed, slightly setose, and approximating length of eyes; peduncleswhen extended exceeding eyes by over one-half length of slightly compressed terminal article; flagella slender, slightly setose. Antennular peduncles when extended exceeding eyes by full length of long slender terminal article; inferior

51

flagellum slender, evenly tapering, about two-thirds length of superior flagellum* Ambulatory legs wide, compressed, slightly longer on right side; merus much compressed, smooth except for slight scales and setae on superior and inferior margins; carpus rounded laterally, crested with small sharp spines, pro­ podus of second pair sometimes similar but often with spines reduced to mere scales; dactyls spinulose, with only sparse setae. Fourth pair of thoracic legs chelate, minute dactyl not bearing rasp which covers pollex and small distal por­ tion of propodus; fifth pair minutely chelate, with tuft of very long setae on distal end of laterally swollen pro­ podus . Membranous abdomen as long as carapace, membranous terga not in contact, caudal shield calcified, suture flex­ ible, anterior tergum transversely and longitudinally con­ vex, smooth, posterolateral corners produced slightly, pos­ terior tergum similar in shape, slightly smaller with few tufted setae on lateral and terminal borders. Telson symmetrical, fringed laterally by setae, pos­ terolateral corners with prominent, flat, downward curving tooth, entire terminal margin between teeth occupied by varying sized denticulations; uropods larger on left side,

52

anterior blade with rasp over most of outer surface, poster­ ior blade much reduced, completely covered by rasp on outer surface. Distribution: Arena Bank and Santa Inez Bay in the Gulf of California.

(Glassell 1937).

Specimens in the Hancock collections are from Ensen­ ada de San Francisco, Sonora, San Pedro Nolaseo Island, Tiburon Island, Isla ^artida, Angel de la Guardia Island, Angeles Bay, Coronados Islands, Gulf of California and Secas Islands, Panama. This species was taken at the following Hancock stations: 449-35 524-36 538-36 546-36 549-36

556-36 559-36 566-36 575-36 699-36

701-37 711-37 712-37 734-37 737-37

738-37 1051-40 1056-40 1725-49 1726-49

The bathymetric range was from 10 to 100 fathoms. The report from Secas Islands, Panama at 7° 57* 35" N. Latitude 82° 01* 35" W. Longitude constitutes the first record of the species outside the Gulf of California. Discussion:

This species is very closely allied

with P. cervicornis.

Glassell (1937) stated, "These two

species, P. varians and P. cervicornis, may prove to be one and the same species, one a variety of the other, when it is possible to get a large series of adult forms from both ends of the Gulf of California together for com­

53

parison.

There seems to be an intergradation which is

difficult otherwise to explain." There exists, indeed, a high degree of intergradation, largely due to the great amount of individual variation in the appropriately named P. varians. in Benedict’s description,

Of the characters used

(Glassell did not redescribe the

species) only one, the type of granules on the major cheli­ ped, was found to be constant for the differentiation of the two forms. A comparison of a series of the two forms was made on the basis of the following eight characters.

The first

seven were described as being typically present in each species.

The type of telson, number eight in the comparison,

was not described by Benedict and the author is responsible for the assignment of the different types to the respective species. 1.

Type of Microscopic Granules on Face of Major Cheliped. £• varians

Granules rounded, constricted at the base, spinule horizontal or almost so, directed anteriorly.

P. cervicornis

(Plate 4, fig. 3).

Granules wide at the base, tapering, spinule apical and directed vertically. (Plate 5, fig. 3).

2.

Arrangement of Marginal Teeth on Lateral Edge of Major

54

Hand. £• varians

Teeth, irregular in size and arrangement.

P. cervicornis

Teeth to some extent alternately large and small.

3.

Meropodite of Major Gheliped. P* varians

Lower margin produced down to an angle or tubercle.

P. cervicornis 4.

Lower margin evenly rounded.

Carpodite of Major Manus. P. varians

Lower surface evenly granular.

(Plate 4,

fig. 4). P. cervicornis

Lower surface with prominent central . spine and a ring of smaller spines. (Plate 5, fig. 4).

5.

6.

7.

Ophthalmic Scales. £• varians

Apex drawn out to a fine point.

P. cervicornis

Apex bluntly pointed.

Median Point of Front. P. varians

Pointed, much in advance of laterals.

P. cervicornis

Angular, slightly in advance of laterals.

Length of Antennal Acicle. P- varians

Acicle same length as the eyes or a little shorter.

P. cervicornis

Acicle longer than the eyes.

55

8.

Type of Telson. £• varians

Posterolateral corners with broad, flat downward curving tooth, entire terminal margin between these teeth armed with varying sized denticulations. (Plate 4, fig. 5).

P. cervicornis

Denticulations restricted to central notch.

(Plate 5, fig. 5).

The comparison of these characters clearly indicates the intergradation of the characters numbered 2 to 7, which makes distinction between the two species practically im­ possible with the original descriptions.

However, the

unique type of granules present on the palm of P. varians is consistently associated with one of the two strikingly different types of telson, and the granules typical of P. cervicornis are without exception associated with the other, clearly indicating that these are distinct species, and affording a quick method of identifying each. Remarks:

The common carcinoecium of this form is

a gastropod shell completely overgrown with a hydrocoral of an as yet undeseribed genus and species, which forms several medial and long upswept lateral spines described by Benedict as f,branches not unlike the horns of a deer.” This is probably the ^bryozoan” encrusted shell mentioned

56

by Boufier (1898) and Glassell (1937) as the habitat of this species*

Pylopagurus' cervicornis (Benedict) 1892 Eupagurus cervicornis Benedict Proc. U8HM 15. (887) p. 25. 1927 Bylopagurus cervicornis. Glassell 2oologica 22 (3) p. 253. Type: Holotype, U. 8. N. M. from unknown locality in the Gulf of California.

(Benedict 1892).

Description: Chelipeds dissimilar, unequal, right vastly larger; merus compressed, almost as deep as long; carpus long, widening proximally to manus, inner margin marked by row of pointed, forward hooked spines, upper sur­ face covered with similar, smaller spines, outer margin marked by row of more closely spaced spines, granular in­ ferior surface produced to a prominence which often, but not invariably, bears a spine surrounded by a circle of seven or eight smaller spines; hand roughly discoidal, oper­ cular face completely margined by corneous tipped spines, and covered by widely spaced pointed granules tipped with vertically directed slender spines. Minor cheliped reaching beyond base of fingers of major hand, carpus bicristate, outer row of spines much

57

the larger; hand depressed, oval, covered with sharp pointed granules; fingers longer than palm, gaping at base* Precervical portion of carapace as broad as long, transversely convex, smooth, glabrous; median point broadly triangular, slightly in advance of angular laterals; postcervical portion membranous, cardiac region distinctly mark­ ed off. Eyestalks stout, terete, constricted in middle; cor­ nea dilated beyond width of stalk; ophthalmic scales gen­ erally acutely triangular, with prominent, acute, subter­ minal spine. Antennal acicle slender, outward-curving, acute, slightly setose, typically, but not invariably, exceeding length of eyes; peduncle when extended exceeding eyes by one-half length of compressed terminal article; flagellum setose. Antennular peduncle when extended exceeding eyes by length of long terminal article; superior flagellum of about twenty simulations, setose beneath, inferior flagel­ lum slender, evenly tapering, about two-thirds as long as superior. Ambulatory legs wide, compressed, slightly longer on right side; merus much compressed, smooth but for slight scales and setae on superior and inferior margins; carpus rounded laterally, crested with sharp spines, propodus of

58

first pair similarly crested, second pair with spines often reduced to mere scales, dactyls spinulose with only sparse setae. Fourth pair of thoracic appendages chelate, minute dactyl not bearing rasp which coders pollex and anterior portion of propodus; fifth pair minutely chelate, with tuft of very long setae on distal end of laterally swollen pro­ podus . Abdomen as long as carapace, membranous, terga mem­ branous, not in contact with one another; caudal shield cal­ cified, suture flexible, anterior tergum longitudinally and transversely convex, smooth, polished, posterolateral cor­ ners produced slightly, posterior tergum slightly smaller. Telson symmetrical, posterior margin with wide, shallow "V"-shaped notch, with flattened, acute, downwardcurving teeth of varying sizes restricted to notch area; uropods larger on left side, anterior blade with rasp over most of outer surface, posterior blade much reduced, com­ pletely covered by rasp. Distribution:

Unknown locality in the Gulf of Cali­

fornia (Benedict), Arena Bank, Gulf of California, 30 to 50 fathoms (Glassell). Specimens in the Bancock collections are from San Pedro Holasco Island, Angel de la Guardia Island, and San Ignacio Bay, Sinaloa, Gulf of California, Mexico.

60

irregularly oval, opercular surface completely margined by small denticles, posterior margin falling just short of carpus so basal angle is quite small; entire surface of hand covered quite uniformly with upright pointed granules, those on opercular surface slightly larger; fingers elon­ gate, crossed at tips dactyl five-eights total length of hand, longitudinally contorted, pollex one-half total length of hand, with prominent tubercle on cutting edge. Minor cheliped much reduced, reaching about to mid­ dle of carpus of major cheliped, merus and carpus slightly setose and hardly more expanded than corresponding articles of ambulatory legs; carpus armed on supero-lateral margin with row of strong forward-curving spines; propodus’quite narrow, flaring abruptly to widest portion at base of fin­ gers, dactyl almost twice the length of propodus, strongly convex in outline; both fingers armed with regular chitinous denticles on cutting edge, gaping at base, and furnished with many tufted setae on under surface, Precervical portion of carapace broader than long, very convex, smooth, polished, median projection quite long and acute, extending beyond bases of eye scales, lateral points angular, shorter than median; postcervical portion naked, membranous. Eyestalks short, cylindrical, constricted in middle and then widening so diameter at base of cornea is greater

59

The complete list of stations at which the species v r was taken is as follows: 544-36 546-36 549-36

708-37 735-37 742-37

1054-40 1055-40 1080-40

1084-40 1725-49 1726-49

The bathymetric range was from 30 to 110 fathoms* Remarks:

The careinoecium is usually a gastropod

shell completely overgrown by hydrocoral.

Pylopagurus longimanus Faxon 1893 Pylopagurus longimanus Faxon, Bull. Mus. Comp. Zool. 24 p. 168. 1895 Pylopagurus longimanus Faxon. Mem. Mus. Comp. Zool. 18 p. 61, PI. 12, figs. 1-le. Type: Five males (gyntyp:es ?) in the Museum of Com­ parative Zoology, Harvard, from Cocos Island, Costa Ri©a, Albatross Station number 3368, in 66 fathoms.

(Faxon 1895).

Description: Chelipeds dissimilar, unequal, right vastly larger, longer than entire body in older specimens; merus compressed, lateral surface smooth polished, lower and medial surfaces granulate, dorsal surface with slightly larger granules; carpus equaling combined length of all three preceding segments, longitudinally convex dorsal sur­ face with pointed granules between well defined lateral margins of larger teeth; hand slightly longer than carpus,

61

than at basal portion, cornea large, dilated ophthalmic scales convex, acute, with prominent, sharp, subterminal spine. Antennal acicles slender, pointed, outward curving, slightly setose, equaling or slightly exceeding length of eyes; peduncles when extended with proximal portion of ter­ minal article even with base of cornea; flagellum setose. Antennular peduncles very long, terrainal segment longer than eyestalks, dorsal flagellum of about twentyfour annulations, densely setose beneath, inferior flagel­ lum evenly tapering, about two-thirds length of superior. Ambulatory legs longer on right side, very slightly setose, merus unarmed on dorsal surface; carpus slightly shorter, with row of sharp spines on dorsal surface; pro­ podus of first pair armed with similar spines, but propodus of second pair unarmed; dactyli of both pairs flattened, spinulose, and longer than related propodus. Fourth pair of thoracic legs subchelate, minute dactyl not bearing rasp which covers pollex and distal por­ tion of palm; fifth pair minutely chelate, rasp covering both minute fingers and most of laterally swollen propodus. Abdomen as long as carapace, membranous; terga mem­ branous not in contact; caudal shield calcified, suture flexible, anterior tergum smooth, posterior corners pro­ duced slightly posterior tergum similar in shape, slightly

62:

smaller, with a few tufts of setae on lateral and terminal borders. Telson symmetrical, incompletely divided by trans­ verse suture, terminal margin armed with denticulations, the most lateral pair on each side largest, then two or three minute teeth, one larger, and a series of rather uniform minute teeth in the center on each side; uropods larger on left side, anterior blade with rasp over most of outer sur­ face, posterior blade much reduced, completely covered by rasp on outer surface. Distribution: Cocos Island, Costa Rica, in 66 fathoms (Faxon 1893). Specimens in the Hancock collections are from off Nuez Island, Cocos Island, and Chatham Bay, Cocos Island. The station numbers are as follows: 772-38 773-38

779-33 780-38

The depth ranged from 30 to 50 fathoms.

Pylopagurus hirtimanus Faxon

1893

Pylopagurus hirtimanus Faxon, Bull. Mus. Comp. Zool. 24 p. 170.

1895

Pylopagurus hirtimanus Faxon, Mem. Mus. Comp. Zool. 18, p. 65, PI. 13, figs. 1-le.

63

Type: Not definitely designated (measurements are for largest male) in a series of seven males and six females from off Cooos Island, Oosta Rica, Albatross station number 3367, 3363, in 66-100 fathoms, deposited in the Museum of Comparative Zoology, Harvard. 38 February 1891.

Collected by the Albatross

(Faxon 1895).

Description: Chelipeds dissimilar, unequal, right vastly larger, merus short, naked, almost as deep as long, lower lateral margin with series of sharp spines; carpus with dorsal surface very hirsute and with scattered small pointed granules, medial margin marked by row of sharp anteriorly curved spines; hand completely margined by row of even sharp teeth except for posterior margin which is ill defined, proximal one-third of dorsal surface setose, hair j area ending abruptly to expose low dome shaped gran­ ules with flat circular bases cut into radiating peripheral processes, covering entire opercular surface. Minor cheliped reaching beyond base of dactyl, over one-half as wide as major hand, merus similar to that of major hand but smaller; carpus very hairy on dorsal surface, bearing median row of sharp curved spines; hand covered with tubercles similar to those of large hand, lateral bor­ der likewise margined as the larger hand, but medial mar­ gin lacking teeth, inferior surface hairy and tuberculose. Precervical portion of carapace wider than long,

64

posterior border extending into rouiided lobe, median projec­ tion in advance of laterals, obtuse, slightly depressed and obscured by tuft of setae near apex, lateral points obtuse but tipped with sharp spinule; post cervical portion mem­ branous, becoming hairy on branchial regions, cardiac reg­ ion defined as quadrangular plate. Eyestalks terete, constricted in middle with median line of tufted setae on dorsal surface, cornea dilated beyond width of stalk; ophthalmic scales convex, pointed, margins entire with subterminal spine slightly protruding. Antennal acicles slender, outward curving, very hairy on medial margin, reaching c©'-KQ?e£uL base; peduncles when extended slightly exceeding reach of eyes, flagellum very slender, greatly exceeding reach of major hand, with short, very fine setae. Antennular peduncles when extended exceeding eyes by one-half length of distally flaring third article. Ambulatory legs of slightly compressed, very

equal length on both sides,

only

hairy on dorsal surface, unarmed

but for single tooth medially on distal end of dorsal sur­ face of carpus and spinules above and below on the dactyli. Fourth pair of thoracic legs very short, subchelate, rasp restricted to terminal margin; fifth pair minutely chelate, outer surface of

swollen propodus covered by rasp,

lower margin with line of

long, silkjr setae.

65

Abdomen obese, terga not distinct except in caudal shield, in which anterior tergum is larger with tufts of setae, convex, front corners rounded, posterior corners produced, suture onljr slightly flexible, posterior tergum with setal tufts on terminal margin. Telson divided into two lobes, both asymmetrical, the posterior greatly so, left side much larger, posterior ma r ­ gin with central notch and bearing several strong, downwardcurving teeth; uropods larger on left side, posterior blade much reduced on both sides. Distribution: 100 fathoms.

Off Cocos Island, Costa Rica, in 66-

(Faxon 1895).

Specimens in the Hancock collections are from off Nuez Island, Cocos Island, Chatham. Bay, Cocos Island, and north of Hood Island, Galapagos Islands,

The station

numbers are as follows: 773-38 780-38 814-38 The depths ranged from 20 to 50 fathoms.

Pylopagurus {?) affinis Faxon 1893

Pylopagurus affinis Faxon, Bull. Mus. Comp. Zool. 34, p. 169.

1895

Pylopagurus affinis Faxon, Mem. Mus. Comp. Zool. 1 8 .

66

p. 64, PI. IE, figs. 2-2d. Type: Male holotype, dredged in 85 fathoms by the Albatross in the Gulf of Panama, Albatross station number 3597, in Mus. Gornp. Zool., Harvard. Description:

Chelipeds, unequal dissimilar, right

vastly larger; upper margin of carpus armed with two or three spines, the anterior spine largest, outer face of carpus smooth except for a light tubercular ridge along the mid­ dle; external (opercular) face flat, covered with minute spinulous granules and surrounded by border of sharp spines, the proximal border not sharply defined by spines from basal portion; lower surface of chela smooth. Minor cheliped very hirsute; inferior border of chela conspicuously toothed. Ambulatory legs hairy; the vasa deferentia are ex­ truded from the base of the fifth leg on each side, appear­ ing as slender threads, the right much longer and twisted. Telson symmetrical, subcircular in outline, its posterior border convex and entire. Discussion:

From the description by Faxon (1895)

of the extruded vas deferens of the male holotype, and the very clear figure of this structure,

(pi. XII, fig. 2c), it

is apparent that this species cannot be assigned to Pylo­ pagurus » or, indeed, to any existing genus.

Without exam­

ining the type specimen the writer cannot feel Justified in

67

either erecting a new genus or in emending the description of Pylopagurus to accommodate this specimen.

The formation

of any opinion regarding this matter should perhaps be re­ served until more specimens are obtained since the single male obtained in 1891 is the only report of this form.

Xylopagurus Milne-Edwards 1880 1880

Xylopagurus M.-Edw.. Bull. Mus. Gomp. Zool. 8, p. 37.

1888

Xylopagurus, Agassiz, Bull. Mus. Gomp. Zool. Ij5, p. 40.

1893

Xylopagurus. M.-Edw. & Bouvier, Mem. Mus. Comp. Zool. 14, p. 106.

1905

Xylopagurus. Alcock, Gat. Ind. Bee. Grust. Pt. 2, Fasc. 1, p. 25.

1950

Xylopagurus, Walton, J, Wash. Acad. Sci. 40 (6), p. 190. Ghelipeds dissimilar, unequal, right much larger;

external maxillipeds widely separated at base; fourth pair of legs subchelate; abdomen long, well developed but not coiled; paired abdominal appendages present on first two somites of male only; caudal shield highly developed, well calcified, ornamented plate with component terga completely fused. Genotype: X. rectus (Milne-Edwards 1880, p. 37).

68

Xylopagurus cancellarius Walton 1950

Xylopagurus cancellarius Walton, J. Wash. Acad. Sci. 40 (6), p. 190, fig. 2'a, h . Type: Female holotype, U, S. N. M.. catalogue no.

90384, from off Port Utria, Colombia in 20 fathoms, male paratype AHF no. 343. Description: Ghelipeds unequal, dissimilar, right vastly larger, inner margin of manus prolonged into triangu­ lar projection two-thirds as large as pollex, fingers strongly curved, occluding only at tips, moderately setose, palm laterally convex throughout proximal half of its length, concave at the base of fingers, distal two-thirds covered with conical granules, proximal one-third smooth, lateral margins of palm subparallel, setose, and- the proximal mar­ gin notched on the dorsal surface to receive the carpal crest; carpus triangular in cross section, with apex the prominent dorsal crest; merus as long as carpus, crest less well developed. Minor cheliped very weak, less than one-third the width of large cheliped and reaching only to distal edge of carpus o f major cheliped, palm subcylindrical, smooth, lightly setose; carpus cylindrical, smooth, not crested. Precervical portion of carapace longer than wide, smooth, well calcified, strongly convex, rostral point tri-

angular, acute; lateral points angular, reduced, extending only to base of rostral point; postcervical portion with well calcified median plate, becoming membranous toward branchial regions. Eyestalks stout, widening distally, corneas dilated; ophthalmic scales small, directed medially, narrow, con­ stricted in the center, rounded distally with nine or ten upward curving spines

011

distal margin.

Antennal acicle very much reduced, extending no far­ ther than eye scales, very narrow, with serrate distal mar­ gin; peduncles when extended reaching only to base of cornea flagellum setose and short, not exceeding large cheliped. Ambulatory legs compressed, smooth, polished, and reaching beyond base of fingers of major cheliped, dactyl only sparsely setose and equaj. in length to propodus. Fourth pair of thoracic legs subchelate and bearing oval rasp; fifth pair minutely chelate. Abdominal terga weakly calcified, asymmetrical, lar­ ger on left side and not in contact with one another, ab­ dominal appendages unequally biramous, the posterior blade being the larger;

caudal shield heavily calcified, roughly

quadrangular, with raised margin around entire perimeter except for a notch on each side marking line of fusion of the two terga, lateral and distal margins composed of reg­ ular rounded granules,: each separated by rounded sinus in

?0

which is a tuft of setae, proximal margin merely raised ridge with regularly spaced fascicles of setae, in center of shield are two pairs of prominent conical tubercles, one pair just anterior-, and one pair posterior to line of fusion of terga. Telson ssnrmetrical, very much reduced, though well calcified, and carried flexed forward to lie flat against the abdomen, dorsal surface marked by a central and two deeper lateral pits, while terminal margin is spinulose; rasp on uropods composed of conical spines rathern than low rounded granules as in the majority of the pagurids. Distribution: Off Port Utria, Colombia in 20 fathoms at station 238-34 and off Isla Ladrones, Panama in 54 fath­ oms at station 943-39. Remarks:

The carcinoecium of this species is the

hollow reed, Typha s p .

The morphology of this hermit re­

quires that it enter its carcinoecium head first instead of backing into it as do other pagurids and it is well adapted to its specialized abode.

The heavy caudal shield

effectively blocks the posterior entrance to the tube while the large claw acts as an operculum to close the front opening, thus barring the entrance of any possible predators.

CONCLUSIONS ON DISTRIBUTION

The region between Point Concpetion and Punta Eugenia, in Baja California, opposite Cedros Island, has long been considered as constituting an overlap area between North Temporgte and Panamic faunal regions (cf. Steinbeck and Rick­ etts, 1941, p. 502).

Garth (unpublished paper 1950), in

considering tire Maioid crabs, believes the area should be extended further southward to Entrada Point outside Magda­ lena Bajr, with a discontinuum in the upper reaches of the Gulf of California. The limited conclusions that may be drawn from the records of a group as small as that treated in this paper do not offer much aid in establishing sharp demarcations of faunal areas.

4

However, these records indicate that.such

a boundary for this group lies within this general area and afford some evidence of the discontinuum in the north­ ern end of the Gulf. Only one of the genera considered, Orthopagurus. is completely North Temperate.

The northern species, 0.

schmitti, is recorded only from Puget Sound and only 0. minimus is of interest in establishing this boundary. Ranging from Skidegate, British Columbia on the north, the species has been taken by Hancock Expeditions to (71)

78

Guadalupe and San Benito Islands on the south.

A chart of

the southern part of this range (Chart I) indicates the southern boundary lies in the Punta Eugenia area. Of the other three predominantly Panamic genera, Cancellus is represented by a single record. Xylopagurus cancellarius, the only Pacific species of the genus, is undoubtedly tropical as is its cognate, X. rectus. on the eastern side of the isthmus of Panama. This species was taken in a short section of a hollow reed, Typha sp., and presumably uses vegetable tubes exclusively, as does the Caribbean form.

At first sight it seems diffi­

cult to imagine a marine animal depending exclusively on land plants to provide a carcinoecium when this protection *

is so vital to the survival of the creature.

However, the

dredgings by the Albatross revealed remains of terrestrial plants present in the Bay of Panama in such quantity that Agassiz (1891) made special comment on this fact, and sur­ mised that it was due to the steepness of the western slope of Central America.

Quite possibly the range of this species

may be found to be limited as much by the availability of reeds on the ocean bottom as to other limiting factors such as depth and temperature. Pylopagurus is predominantly a tropical form in the Eastern Pacific as it is in other waters.

However, the

records of P. guatemoci reported above obviate the possi-

73

bility that the type locality off Baja California (the only previously reported occurrence) is on the very northern extreme of the range of the species and that it is also a Panamic form.

It how seems clear that it is a member of

the North Temperate fauna (Chart I), with its south bound­ ary also approximately at Punta Eugenia.

The one record

from the Gulf of California is significantly In the upper third of that body of water, and indicates the discontinuum of the range of this species in that area as was reported for some Maioid crabs by Garth. Another species, P. holmesi, affords records which are difficult to reconcile with other distributional data. The northern segment of its range (Chart I) seems to indi­ cate that it would correspond rather closely to-that of P. guatemoci, with a sharp break around the Punta Eugenia area.

However, the range in the Gulf is not restricted to

the northern end, but there are several occurrences in the presumably tropical southern end.

Moreover, these southern

records are more anomalous In that some of them represent the shallowest records for the species.

This is the

direct opposite of the usual ease of the occurrence of northern forms In progressively deeper (colder) water as they range southward.

It seems probable that this form

might prove to be an exception to the principle

... that

the temperature of the sea is the chief factor governing

74

the distribution of marine crustacea,” as stated by Faxon (1895). £• lon^imanus and P. birtimanus are undoubtedly Panamic species.

Of P. spinicarpus. P. coronatus. and

£• glasselli » the few records necessitate reservation of

a

decision, although it is most likely that these species are also tropical (Panamic), as is most of the genus. P. varians and P. cervicornis have almost identical reported ranges (Chart II with the exception of the Becas Islands, Panama record for P. varians (not shown on chart). This discontinuity of

range will no doubt be eliminated by

further collecting in

the intervening area, since there

seems to be no apparent reason why these Panamic forms would not range throughout this region.

SUMMARY

Within the Paguridae, the sub-familial name "Pagurinae" is found to be valid and to have priority over the much used "Eup agur ina e ." Three genera of the anomalous "Straight-line" pagurids. from the Eastern Pacific are embraced by this study: Orthopagurus» Pylopagurus, and Xylopagurus.

Of this group one

species and one sub-species of Pylopagurus are new. Specimens of Pylopagurus guatemoci were found with the females lacking the paired abdominal appendages character­ istic of the genus due to parasitic castration. P. guatemoci is reported for the first time in waters north of Baja California, and P. varians for the first time outside the Gulf of California.

Qrthopagurus minimus. Pylo­

pagurus holmesi, and Pylopagurus guatemoci are found to be members of the North Temperate Fauna and the remainder of the species to be Panamic.

The boundary between the two

Provinces occurs in the Punta Eugenia region in Baja Cali­ fornia.

(75)

LITERATURE CITED

Agassiz, A* 1888

Three Cruises of the .... Blake. Vol. II. Bull. Mus. Comp. Zool. 15, 220.pp., 545 figs.

1891

Three Letters on the Dredging Operations off the West Coast of Central America. Bull. Mus. Como. Zool. 21:185-200.

Alcoek, A. 1905

Catalogue of the Indian Decapod Crustacea in the Collection of the Indian Museum. Part II Anomura. Fasiculus I Paguridea. Calcutta, xi and 197 pp., 16 pis.

Barnard, K. H. 1950

Descriptive Catalogue of South African Decapod Crustacea (Crabs and Shrimps), Addehda, Descrip­ tive List of South African Stomatopod Crustacea (Mantis Shrimps). Ann. S. African Mus. 38, 864 pp., 158 text figs.

Benedict, J. E. 1892

Preliminary Descriptions of Thirty-seven New Species of Hermit Crabs of the G-enus^ Eupagurus in the United States National Museum. Proc. U.S.N.M. 15 (887)j1-26.

1896

A Question Concerning a British Pagurid. Mag. Nat. Hist. Ser. 6 18:99-100.

1901

Four New Symmetrical Hermit Crabs (Pagurids) from the West India Region. Proc. U.S.N.M. 23 (1256: 771-778, 7 text figs.

1902

The Anomuran Collections Made by the Fish Hawk Expedition to Porto Rico. Bull. U.S. Fish Comm. 20 (2):131-148, pis. 3-6.

1928

Crustacea from the Tropical East American Seas. Bull. Bingham Ocean. Coll. 1 (2), 147 pp., 33 figs. (7fc)

Ann. &

77 Bouvier, 1. L. 1898

Sur quelques Crustaces Anomoures et Brachvures Recueillis par M. Diguet en Basse-Californie. Bull. Mus. Bat. Hist. Paris 4 (8):371-384.

Brandt, F . 1851

Dr. A. T. von MiddendorffTs Reise in den fiussersten 'Borden und Osten Bibiriens. 2 (l), Krebse, 516 pp.

Buitendijk, A. 1937

Biological Results of the Snellius Expedition IV, Paguridea. Ternminckia 2 : 251-280.

Chace, F. A. 1939

Reports on the Scientific Results of the First Atlantis Expedition to the West Indies...Seven­ teen New Species of Decapod and Stomatopod Crus­ tacea. Mem. Soc. Cubana Hist. Nat. 15:31-54.

Dana, J . D . 1852a

United States Exploring Expedition 13, Crustacea (l), 685 p p . , 96 pis.

1852b

Conspectus Crustaceorum quae in Orbis Terrarum Circumnavigationae, Carolo Wilkes e classe ReipUhlicae Foederatae Duce, lexit et descripsit. Acad. Nat. S e i . Phila. J5:2S7-272.

Fabricius,