THE GLAUCOTHOES OF PETROCHIRUS DIOGENES (L.) AND TWO OF DARDANUS (: )I ANTHONY J. PROVENZANO, JR. Institute of Marine Science, University of Miami

ABSTRACT The post-zoeal stages of three hermit crabs, Dardanus scutellatus of the Pacific and two west Indian forms, D. insignis and Pe~rochirus diogenes, were identified and described in detail. Characters of specific and generic significance were discussed. Glaucothoes of P. diogenes and several species of Dardanus are similar in all features distinguishing them from described glaucothoes of other genera. Differences between the post-zoeal stages of P. diogenes and Dardanus ssp. are no greater than differences among species of Dardanus. A plot of size vs number of telson setae for four species suggests that morphologically similar glaucothoes may be differentiated by this or similar means.

INTRODUCTION Although taken only rarely, among the most distinctive of the crusta- ceans occurring in the plankton are those forms usually designated only as "pagurld glaucothoes." Identification of these to the generic level has been possible only in very few instances until recent years. How- ever, study of larval and post-larval hermit crabs by several workers has permitted the recognition of familial characters and the identification of specimens to generic and sometimes specific levels in some localities. In a previous paper, distinguishing familial characters of pagurine post-larvae were noted, and a list of the known glaucothoes of the family Diogenidae was given in the introduction to a detailed description of a Dardanus glaucothoe (Provenzano, 1963). A comparison of the post-zoeal stage of Dardanus venosus with other known glaucothoes indicates that the form of the telson and other morpho- logical features may be used to separate, at least at the generic level, all the known diogenid glaucothoes. Among the features apparently dis- tinguishing Dardanus glaucothoes from those of other diogenids are very large size, elongate telson, and presence of tooth-like processes on the ventral margins of the dactyls of the ambulatory legs. Unfortunately, there have been no adequate descriptions and illustrations for the three other species of Dardanus glaucothoes known and thus detailed comparison of the post-zoeal stage of D. venosus with that of other species within the was not possible. lContribution No. 470 from the Marine Laboratory, Institute of Marine Science, University of Miami. This research was supported by National Science Foundation grants GI6298 and G20355. 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 243 The genus Petrochirus contains only three recognized Recent species, one on each side of the Central American land barrier and one off West Africa. No larvae are known for the genus. The species are similar in many ways to Dardanus, despite the fact that Petrochirus is the only genus in the family with the right hand larger than the left. Dechance and Forest (1958) suggested that the glaucothoe is probably similar to that of Dardanus. A number of glaucothoes have been accumulated and studied and, on the basis of facts given below under the heading of each species, the identities of several have been established. The present paper provides descriptions and illustrations of the glaucothoes of three species of large diogenid hermit crabs. It is one of a series providing basic descriptive data to aid identification of planktonic forms and to facilitate eventual detailed comparison of the larvae and post-larvae of paQUrid crabs. Such informa- tion may be considered in evaluation of systematic relationships within the group. I wish to thank Charles E. King for the specimen of Dardanus scutellatus and for permission to use it in the present study. I am pleased to acknowl- edge the assistance of Walter A. Starck, II and William Davis in obtaining material for study.

THE GLAUCOTHOEOF Dardanus scutellatus (H. MILNE-EDWARDS,1848) Material.-1 specimen taken in company with 8 Diogenes gardineri, 4 Calcinus latens, and 16 Dardanus scutellatus ranging in size from first crab to ovigerous females, from Charles E. King's quadrant F-2-N, 16m2, about 40 yards offshore on lagoon side of Chinimi Island, Eniwetok Atoll, at a depth of 22 feet. Substrate: coral lime sand and rubble. 10 July 1961. Size.-CL 2.2 mm; TL 6.8 mm. Description.- The carapace, as in diogenids generally, is less than half the total length of the measured from the tip of the projecting but blunt rostrum to the posterior margin of the telson. The anterior portion of the thoracic shield is nearly half again as long as the posterior portion and is only slightly longer than wide. The eyes are widest at the cornea, width being two-thirds the length. The antennae exceed the chelipeds which do not reach to the dactyli of the walking legs. In the present specimen, which is a late glaucothoe, the abdomen has a slight twist due to the asymmetry of the crab stage which is well formed within the exoskeleton of the post-larva. The Tail Fan (Fig. 1,a) The telson has a LjW ratio of about 1.5. It is broadest proximally and tapers smoothly to about half maximum width. On the posterior margin 244 Bulletin of Marine Science of the Gulf and Caribbean [13(2) of the telson there are 15 plumose setae and about three additional pairs of smaller setae distally on each of the lateral margins. There is a median row of at least eight pairs of short setae and there are additional setae dorsally on the telson. The telson of the first crab stage is visible through the exoskeleton. The left lobe of the bifurcated telson of the crab is larger than the right, and both lobes have a few setae on the posterior margin. The protopod of the glaucothoe uropod on each side has a prominent spine. The exopodite of the uropod has about 45 straight setae fringing its margins, with about six additional curved setae on the postero-Iateral side. There are about a dozen corneous granules on the postero-Iateral margin of the exopodite. The endopodite is smaller than the exopodite and is more pointed posteriorly. There are about 30 setae lining the margins of the endopodite and about five corneous granules on the postero-Iateral margins of each. The Pereiopods The chelipeds (Fig. 2,a,a') are subequal; the hand is about two and a half to three times longer than high. The dactyli each have clusters of setae and two blunt teeth.

a

b FIGURE 1. The tail fan of: a, Dardanus scutellatus; b, D. insignis; and c, Petro- chDrusdiogenes. 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 245 The second pereiopod (Fig. 3,a) has the dactyl about half as long as the slender propodus. The dactyl has a horny terminus and two large distally curving processes on the ventral margin. There is a third, similar but much smaller process distally. There are several large setae on the ventral margin. These processes are of considerable significance since they are not found in the glaucothoes of at least three other diogenid genera for which -the post-larva is known. The third pereiopod (Fig. 3,d) is similar to the second but the ventral processes of the dactyl are more strongly curved toward the terminus. The fourth pereiopod (Fig. 4,a) is subchelate; there is a very long seta and several shorter ones on the dactyl. The propodus bears a double row of corneous granules which total about eight, and a number of setae. The fifth pereiopod (Fig. 4,d,d') is chelate; the immobile dactyl has about seven corneous granules. There are a number of large setae on the distal portion of this appendage, some of them curved. The propodus is about four times longer than broad.

Other Appendages The antennule (Fig. 5,a) consists of a jointed peduncle upon which there is a four-segmented ventral, or inner, ramus and a nine-segmented(?) dorsal, or outer, flagellum which bears numerous aesthetes on segments two to five. The antenna (Fig. 5,d) consists of a 19-segmented flagellum upon the peduncle. The antennal scale is a simple, ovate lobe. The mandible (Fig. 6,a,tr) consists of a stalked cup with a three-seg- mented palp bearing about 13 short setae. The maxillule (Fig. 6,d,d') has an apparently unsegmented endopodite bearing a single terminal and a smaller proximal seta. The basal endite bears about 15 stout setae distally and at least 17 others. There are three fine marginal setae. The coxal endites of both maxillules of the single specimen were damaged during dissection. The maxilla (Fig. 6,g) has the scaphognathite with a posterior lobe bearing about 70 setae. The distal lobe of the basal endite has about 17 setae, the proximal lobe about 12. The distal lobe of the coxal endite bears about five setae, the proximal lobe about 17 in two rows. The first maxilliped (Fig. 7,a) has a short, unsegmented exopodite bearing about 11 plumose setae laterally and a simple unarmed endopodite. The basal endite has at least 24 setae along its distal margin, some of them stout and bearing setules. The second maxilliped (Fig. 7,d) bears upon the basipodite a two- segmented exopodite which has more than nine setae distally upon the terminal portion and two medial setae on the proximal portion. The four- 246 Bulletin of Marine Science of the Gulf and Caribbean [13(2) segmented endopodite bears about 10 setae on the terminal segment, a few setae on the proximal segments. The third maxilliped (Fig. 7,g) bears about 13 plumose setae on the exopodite. The terminal segment of the five-segmented endopodite bears about 21 setae, some of which are serrated; the penultimate segment bears about 15. The antepenultimate segment bears about 10 setae, most of them distally. There is only one obvious seta on each of the two proximal segments. The most proximal has a row of conical teeth on the interior medial margin. The pleopods (Fig. 8, top) of which there is a pair on the second, third, fourth, and fifth abdominal somites, are biramous. The pleopods become relatively shorter and wider from anterior to posterior. The endopodites are long and narrow and bear three minute hooks or corneous processes on the distal margin. The endopodite of the fifth pleopod bears four setae on the medial margin. The endopodite of the fourth pleopod bears three setae; that of the third pleopod two setae. The endopodite of the pleopod of the second somite bears two very minute setae. The exopodites are suboval and bear 10 plumose setae. Identification.-During the course of identification of a large collection of littoral hermit crabs from Eniwetok Atoll, the glaucothoe attributed here to D. scutellatus was discovered. It was in the same vial with, and had been collected with, a first crab stage of Dardanus scutellatus. These speci- mens had been collected at one of a series of stations under study by a graduate student. The entire area was collected by divers who attempted to remove all hermit crabs from each of several measured quadrants. The quantitative collections had been sent to me for identification and the only species found in these collections in any numbers were: (1) a species of Diogenes (D. gardineri Alcock, fide J. Forest, personal communication) the adults of which were usually smaller than the glaucothoe in question; (2) Calcinus latens (Randall), another small species belonging to a gentls for which two glaucothoes are known, both very different from the one under discussion; and (3) a large number of Dardanus scutellatus of all sizes. The only other species present in the sample of 454 individuals taken from 16 contiguous quadrants, each of 16 m2 area, were a single unidenti- fied Calcinus (believed to be an undescribed species), three specimens of Dardanus not in satisfactory condition for positive assignment to D. scutellatus, and one specimen of Dardanus sanguinolentus (Quoy & Gai- mard). Other genera are known from Eniwetok and nearby atolls, but from the present quantitative information it is very probable that the post- larva described above represents D. scutellatus.

THE GLAUCOTHOE OF Dardanus insignis (SAUSSURE, 1858) Material.-Three specimens from the stomach of black-fin tuna (Thunnus 1963] Provenzatw: Glaucothoes of Diogenid Hermit Crabs 247 atlanticus}, off Alligator Light, Florida Current, 21 June 1960, W. A. Starck, II. One specimen with CL 3.9 mm and TL 11.9 mm. The other specimens with CL 4.0 mm. One specimen, CL 3.7 mm, from GERDAstation G-52, cruise 6223, Isaacs-Kidd midwater trawl, from 25°36'N 80002'W to 25°40'N 79°52'W, estimated 100 m fishing depth, between 1940 and 2205 hrs., 27 August 1962. One specimen, CL 3.9 mm, from GERDAstation G-63, cruise 6223, Isaacs-Kidd midwater trawl, from 25°28'N 79°57'W to 25°20'N 80000'W, estimated fishing depth 100 m, between 1827 and 2110 hrs., 29 August 1962. One lot consisting of more than 300 specimens, from stomach of a bonito (Euthynnus sp.), taken 3 mi. east of Government Cut, Miami, Flori- da, September 1962. The description is based primarily on the best specimen from the tuna stomach. Description.- The carapace has an obtuse rostrum pr.njecting well beyond the antero-lateral corners. The anterior portion of the c;uapace is more than one-half the total length of the carapace and is as wide as it is long.

FIGURE 2. Lateral and dorsal views of first left pereiopod of: top, Dardanus scute/latus; middle, D. insignis; and bottom, Petrochirus diogenes. All scales represent 1.0 mm. 248 Bulletin of Marine Science of the Gulf and Caribbean [13(2) The Tail Fan The telson (Fig. 1,b) is longer than broad with a L/W ratio of 1.605. The narrowing of the telson from anterior to posterior is not as well marked as in the preceding species. There are 13 plumose setae on the posterior margin of the telson on four of the five specimens, 14 on the other, and three additional setae on each lateral margin. On the dorsal surface there are at least three pairs of setae. The protopod of the uropod bears a prominent posterior spine proximally, The exopodite bears in excess of 45 se'tae marginally and 16 corneous granules. The endopodite bears about 29 setae and on the posterolateral margin about 12-13 corneous granules.

The Pereiopods

The chelipeds (Fig. 2,b,b1) are subequal. The manus is about two times longer than high. The movable dactyl has two or three blunt .teeth and there are scattered coarse setae on both dactyli and a few along' the d,orsal and ventral margins of the manus. , The .second pereiopod (Fig. 3,b) has the dactyl more than half as long as the propodus. Two ventral curved processes are present but they do not curve distally as much as those of D. scutellatus. Rather, they curve hardly at all. The third peieiopod (Fig.. 3,e) also has the dactyl ,considerably more than half the length of the propodus, a~ the ventral corneous processes point directly ventrally and do not curve toward the terminus as do those of D. scutellatus. There 3{e long setae ventrally on the dactyl.

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FIGURE 3; Second and third left pereiopods, respe¢tively; of: a, d, DatOanus seutellatus; b, e, D. insignis; e, e', I, Petroehirus diogenes. 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 249 The fourth pereiopod (Fig. 4,b) is subchelate, the dactyl terminating with a long setae. There are a number of moderately long setae on the dactyl, propodus, and carpus. The propodus has two or three rows of corneous granules on the distal ventro-Iateral surface of the segment. The fifth pereiopod (Fig. 4,e) is chelate. The dactyl has four long curved setae and a number of smaller ones. The propodus bears numerous setae on the immobile dactyl and about 12 corneous granules on the exterior surface of the distal portion of the propodus. The other segments each bear a few setae. Other Appendages The antennule (Fig. 5,b) bears upon the penultimate segment of the peduncle a single long seta dorsally and a few short ones distally. The ultimate segment bears only a couple of very small setae. The four-seg- mented inner, or ventral, ramus bears about four setae distally. The ten- segmented outer, or dorsal, ramus bears five or six setae distally and on segments two to seven there are numerous aesthetes. The antenna (Fig. 5,e) has about 21 segments in the flagellum. The terminal segment bears one seta as long as the segment itself and two or three other setae. The antennal scale is a suboval rudiment. The mandible (Fig. 6,b) consists of a stalked cup with a three-seg- mented palp bearing a dozen setae on the terminal segment, plus one proximally on that segment. The maxillule (Fig. 6,e) has a non-segmented endopodite with a single terminal seta and another seta proximally. The basal endite bears about 21 setae terminally, some of which are strong and tooth-like, and three proxi- mally. The coxal endite bears more than 2'0 setae distally, of which six of the distalmost are stronger than the others and curved. There are about eight fine setae on the margin toward the basal endite. The maxilla (Fig. 6,h) bears a scaphognathite with about 85 setae lining its margins. The endopodite is a simple, unsegmented elongated lobe.. The distal lobe of the basal endite bears about 12 setae, the proximal lobe seven or eight. The distal lobe of the coxal endite bears six to eight (?) setae, the proximal lobe about 20 in two rows, one row terminally and the other subterminally. The first maxilliped (Fig. 7,b) has 16 setae on the lateral margin of-the exopodite of one appendage. There are only nine visible on the exopodite of the other side of the same animal. The endopodite is a simple unarmed lobe. The basal endite has about 21 setae marginally and sev~n sub- marginally. The second maxilliped (Fig. 7,e) bears about a dozen setae on the distal portion of the exopodite, and about three medial setae on the proximal 250 Bulletin of Marine Science of the Gulf and Caribbean [13(2)

FIGURE4. Fourth and fifth pereiopods of: a, d, d', Dardanus scutellatus; b, e, D. insignis; c, /, Petrochirus diogenes. portion. The four-segmented endopodite bears at least seven setae on the terminal segment, about seven distally on the penultimate segment, none on the antepenultimate segment and two medial setae on the proximal segment. The third maxilIiped (Fig. 7,h), which is larger than the second, has a similar exopodite except for an absence of setae on the proximal portion. The five-segmented endopodite bears at least a dozen setae on the terminal segment, more than 20 on the penultimate segment, and about 17 on the . antepenultimate segment. The next segment has one strong seta laterally and three others. The proximal segment bears three setae medially and has a row of conical teeth on the inside surface. The pleopods (Fig. 8, middle) have four minute hooks on the distal margin of the endopodites. There are setae present medially on the endo- podites in numbers which happen to correspond to the somites on which the pleopods occur, i.e., two on that for the second abdominal somite, three 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 251

FIGURE 5. Antennules and antennae of: a, d, Dardanus scutellatus; b, e, D. insignis; c, t, Petrochirus diogenes. on the pleopod for the third somite, four and five on the next somites respectively. Identification.-The identification of this glaucothoe is tentative and per- haps much less certain than the others described in this paper. It is cer- tainly a Dardanus, and as the glaucothoe of D. venosus is already known and the only other species reported from the West Indies is D. insignis (Saussure, 1858), it would seem very likely to be the latter species. How- ever, I have three specimens of a large, very colorful and distinctive Dar- danus to be described in the near future which were taken from two locali- ties in the West Indies. The existence of this species, unsuspected a few months ago, renders less positive an identification that otherwise would have seemed highly probable. Since the above was written, a glaucothoe similar to that described was collected in the Straits of Florida and held to metamorphosis. The glauco- thoe had a CL of about 3.8 mm and 14 processes on the telson. The crab stage obtained from it was, indeed, Dardanus insignis. I wish to thank my colleagues, Sheldon Dobkin and Won Tack Yang, for making confirmation of the identification possible by their efforts at sea and in the laboratory. 252 Bulletin of Marine Science of the Gulf and Caribbean [13(2) THE GLAUCOTHOEOF Petrochirus diogenes (LINNAEUS,1758) Material.-l specimen, CL 3.0 mm, canal, s. [sic] si:le, Marathon, Florida, October 1958, A. Jones. 4 specimens, CL 3.15-3.25 mm, "Caribe" sta. 15, R/V GERDAcruise 5907, 17°41.5'N, 76°4'O.5'W - 17°50'N, 76°45'W, 1930-2130 hrs., 6 May 1959, at depth of ca. 30 meters. 2 specimens, CL 3.2 mm, 3.4 mm, "Caribe" sta. 19, R/V GERDAcruise 59'07, 1r08'N, 75°02'W - 17°05'N, 74°52'W, 0950-1150 hrs., 10 May 1959, at depth of ca. 200 meters. 1 specimen, CL 3.25 mm, grass flat on beach in front of Marine Lab, Bear Cut, Biscayne Bay, Florida, 8 October 1959, CRR-F-204. Proven- zano. 1 specimen, CL 3.4 mm, Long Reef, Florida, 13 Dec. 1959, Provenzano, Mar. BioI. field trip. 1 specimen, CL 3.25 mm, CT-178b, 14°55'N, 64°50'W, 2200-2300 hrs., 22 Nov. 1960. 2 specimens, CL 3.3, 3.3 mm, R/V GERDAstation G-l1, cruise 6210, 25°41'N, 79°54'W to 25°41'N, 79°50'W, Isaacs-Kidd midwater trawl, estimated depth between 100-150 m, 0026-0149 hrs., 26 May 1962. 3 specimens. CL 3.0, 3.2, 3.1 mm, R/V GERDAstation G-46, cruise 6222, 25°39.5'N, 79°58'W and east, Isaacs-Kidd midwater trawl, esti- mated depth 8'0-100 m, 1510-1906 hrs., 21 August 1962. 4 specimens, CL 3.2, 3.2, 3.1 mm, R/V GERDAstation G-47, cruise 6222, 25°39'N, 79°40'W, Isaacs-Kidd midwater trawl, 930 m of wire let out at 1906 hrs. fouled, hauled in, 21 August 1962. 3 specimens, CC 3.2, 3.2, 3.2 mm, R/V GERDAstation G-69, cruise 6229, 25°28'N, 79°41'W to approx. 25°24'N, same longitude, Isaacs-Kidd midwater trawl, estimated depth 50-75 m, 2252-2400 hrs., 26 September 1962. Size.-Carapace length, CL, varied from 3.0 - 3.4 mm in the material ex- amined. The total length, TL, was difficult to measure in most specimens because of distortions of the abdomen. The TL of the specimen from Long Reef was about 10 mm. The following description is based chiefly on that specimen. Description.- The anterior shield of the carapace is about as wide as it is long, and its length makes up more than half the length of the carapace. The apparently bitobed rostrum is blunt but projecting and dips ventrad. The lateral and posterior margins of the carapace are lined with very fine setae. The antennae exceed the chelipeds by a small amount and the latter do not reach beyond the propodi of the walking legs. There are a few short, narrow, red stripes still visible in this specimen: two on the dorsal 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 253 margin of the manus, four on the dorsal and two on the ventral margins of the propodus of the second walking leg, and one on the ventral margin of the carpus of that appendage. The Tail Fan The telson (Fig. 1, c) is two and a half times longer than the minimum width, but is one and a half times the maximum width. The greatest width is at the anterior third of the telson which tapers gradually from the anterior third to the posterior. There is a slight widening at the extreme posterior portion of the telson, and the postero-Iateral comers are each armed with a very strong, fused spine. These spines are the most characteristic feature

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FIGURE 6. Mandibles, maxillules, and maxillae of: a, a', d, d', g, Dardanus scutellatus; b, e, h, D. insignis; and c, t, i, Petrochirus diogenes. 254 Bulletin of Marine Science of the Gulf and Caribbean [13(2) of this glaucothoe. There are 12 setae between the spines and three on each lateral margin. The protopod of the uropod of the telson has a promi- nent posterior spine proximally. There are in excess of 36 setae on the margins of the exopodite, and about 13 corneous granule~ along its pos- terior margin. The suboval endopodite bears a minimum of 25 setae along its margins and carries about seven corneous granules along the postero- lateral border. In the present specimen, the crab stage may be seen beneath the exo- skeleton. The telson of the crab is bifurcated, the left lobe very slightly larger than the right, each lobe with three teeth or broad spines and about four setae. Both exopodite and endopodite of the crab uropods have more and better developed corneous granules which, at that stage, form the typical rasp. The Pereiopods The manus of the cheliped (Fig. 2, c, c') is more than two times longer than high. The dactyl composes less than half the length of the manus. The merus is at least two times longer than its greatest width. The finger- tips of both dactyls are corneous and there are scattered setae on the dactyls. The chelae of the crab are visible within the exoskeleton of the glaucothoe. The dactyl of the second pereiopod (Fig. 3, c, c') is two-thirds the length of the propodus. The dactyl has a pair of ventral processes which curve very slightly toward the terminus of the dactyl. There are a few very strong setae on the ventral and on the dorsa-lateral margins of the dactyl. There are two ventrally on the distal portion of the propodus. The third pereiopod (Fig. 3, f) also has the dactyl more than half the length of the propodus. The two ventral processes curve very distinctly toward the body, not toward the terminus of the dactyl. There are a few ventral and dorsal setae on the dactyl. The fourth pereiopod (Fig. 4, c) is subchelate, with three (?) rows of corneous granules forming the rasp. There are a few setae scattered distally on the last three segments. The fifth pereiopod (Fig. 4, f) is chelate, with many long curved setae on the propodus and dactyl. There are a few granules on the propodus and the dactyl. Other Appendages The antennule (Fig. 5, c) bears numerous aesthetes on segments two to nine of the dorsal, or exterior, flagellum, and a few short setae on other segments distally and on the four-segmented ventral, or inner, ramus. The antepenultimate segment of the peduncle has a very large curved seta on the dorsal margin at the middle of the segment. Provenzano: Glaucothoes of Diogenid Hermit Crabs 255

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FIGURE 7. First, second, and third maxillipeds of: a, d, g, Dardanus scutellatus; b, e, h, D. insignis; and c, f, i, Petrochirus diogenes. 256 Bulletin of Marine Science of the Gulf and Caribbean [13(2) The antenna (Fig. 5, f) has a minimum of 24 segments, some of which show two segments inside the exoskeleton. Each segment has a few short setae. There are none on the segments of the peduncle. The scale is suboval with four short setae. The mandible (Fig. 6, c) consists of a stalked cup with an apparently three segmented palp, bearing about 21 setae on the distal segment, and one more proximally. The maxillule (Fig. 6, f) bears an indistinctly segmented endopodite with a terminal seta and a smaller seta proximally. The basal endite bears about 25 setae some of which are very strong and toothlike. The coxal endite has two rows of many setae, one along the distal margin, the other subdistally. The maxilla (Fig. 6, i) has a well developed scaphognathite bearing about 73 setae. The endopodite is a simple, unsegmented and unarmed projection. The distal lobe of the basal endite bears about 17 setae, the proximal lobe about 15. The distal lobe of the coxal endite bears eight setae, the proximal lobe has two rows, one of 20 setae marginally and another of about 10 submarginally. The first maxilliped (Fig. 7, c) has 12-13 setae on the exopodite which is a broad lobe. The endopodite is a simple, unsegmented process with a terminal seta. The basal endite has about 18 setae, the coxal endite about 13. The second maxilliped (Fig. 7, f) has about 11 plumose setae on the tip of the exopodite and a few simple setae more proximally. The four- segmented endopodite has about six or seven setae on the terminal seg- ment, about five on the penultimate segment and at least two distally on the antepenultimate segment. The proximal segment has two large setae medially. The third maxilliped (Fig. 7, i) has about 11 plumose setae on the tip of the exopodite. The five-segmented endopodite bears from 15-20 setae on the terminal segment, some of them serrate. The penultimate segment bears at least 14 setae and the antepenultimate seven media-distally. The next segment proximally bears five setae and there are a few on the proxi- mal segment. This latter also has a median row of 10 conical teeth and proximally a short second row of three. The pleopods (Fig. 8, bottom) are biramous and become successively shorter and broader from anterior to posterior. The endopodite of each bears five corneous hooks distally. There are 12 plumose setae on the exo- podites of each of the pleopods. On the endopodites of pleopods of somite two, no setae are distinguishable but on somite three the endopodite has four setae and there are six setae on the endopodite on abdominal somite four, and five setae on that of somite five. 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 257

FIGURE 8. Plea pods of second, third, fourth, and fifth abdominal somites of: top. Dardanus scutellatus; middle, D. insignis; and bottom, Petrochirus diogenes. 258 Bulletin of Marine Science of the Gulf and Caribbean [13(2) Identification.-The symmetry of the present form indicates that it is a post-larva of a diogenid hermit. The generic placement has been made possible by recent progress eliminating other alternatives. Glaucothoes of nearly all Western Atlantic genera of diogenids are now known. The pres- ent form bears little resemblance to glaucothoes described for Coenobita, Calcinus, Clibanarius and Paguristes. Cancellus and Isocheles glaucothoes have not been described but what is probably one of the former is at hand and is quite different from other known glaucothoes. Moreover the species of Cancellus, in these waters at least, are all deep-water forms. No Isocheles have ever been taken east of the Florida Keys, nor would either genus be likely to occur in the shallow water habitats of Long Reef and Bear Cut beach. On the other hand, large species of Dardanus and Petrochirus are common in both places. Although there are at least three species of Dar- danus in the West Indies (one of them undescribed), only D. venosus occurs in the habitats mentioned and, as the glaucothoe of this form has already been described, the only remaining alternative for the identification of the form with a toothed telson is Petrochirus diogenes. The occurrence of an early crab stage of Petrochirus with one of the glaucothopc; tends to support this identification. It has not been possible as yet to rear this species from the egg as no berried females have become available, nor have plank- tonic glaucothoes been maintained to the moult to first crab. A preliminary evaluation of characters of glaucothoes is planned for a later paper but some data obtained during this study are presented here to make them available and to encourage the collection of similar infor- mation. The size of diogenid .!!Iaucothoesvaries considerably. Paguristes tortugae glaucothoes have a total length of 1.7 mm (Provenzano, unpubl.), whereas the 10-12 mm total lengths of the species described herein places them among the largest of the glaucothoes known, exceeded in size only by some pagurid post-larvae of unknown identity. Petrochirus diogenes glau- cothoes may be distinguished immediately from those of Dardanus spp. on the basis of the toothed telson alone and therefore variation in size and other characters, such as setation of the telson should give an indication of the range within a single species. Similar data for Dardanus venosus obtained since the paper describing the post-larva of that species was sent to press, and for D. scutellatus, a Pacific species, when plotted, showed sufficient distinction that it was thought a length vs. telson-seta plot might be helpful in differentiating glaucothoes not so readily separable on quali- tative morphological characters. Data from four specimens attributed to D. insignis (Saussure) when so plotted showed a distinct separation from those of D. venosus. An additional 40 specimens were selected on the basis of good condition from a sample of about 100 specimens of the 300 or more in a bonito stomach, and data were taken from them. The results of 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 259

4.0 A ~£ 6 [Jt. an\\ 6 ~ lSI. & A 1m ~ ~ G A t:. tm t:. 1m t:. t:. 3.5 • • • :a • 8 0 :a I • • • ~3. 0

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2.0,:-_~_~_~ ---+- __ ~_~ __ 10 II 12 13 14 15 16 17 18 19 TELSON SETAE

FIGURE 9. Size vs. number of telson setae in four diogenid glaucothoes: squares represent Dardanus scutellatus; open circles, D. venosus; solid circles, Petro- chirus diogenes; triangles, Dardanus insignis (the open triangles denote speci- mens from bonito stomach). these plots are shown in Figure 9. The graph shows distinct data groupings for the four species of large glaucothoes. The sample from the bonito stomach is assumed to represent one species. There were no obvious mor- phological differences among individuals comprising this sample, but it could contain post-larvae of the undescribed Dardanus as well as of D. insignis. From the groupings of the distinguishable post-larvae of several dio- genids, one may hope that, in the future, similar approaches might help in recognition of closely related glaucothoes. Certainly, any specimen which falls outside the size or seta-count range already known for some species should be checked carefully for other morphological differences. 260 Bulletin of Marine Science of the Gulf and Caribbean [13(2) DISCUSSION The features by which the glaucothoe of Dardanus venosus differs from those of other diogenids known, were given in an earlier paper. However, the specific, or generic, nature of these and other characters not discussed was difficult to assess, since the only other information on Dardanus post- larvae was fragmentary. The present results permit a comparison of glau- cothoes of several species within the genus. Among the features setting apart the glaucothoe of Dardanus venosus from those of other diogenids were mentioned the large size, elongate telson and the ventral hooks on the ambulatory dactyls. These characters, which were also found in the two Dardanus glaucothoes described herein, are apparently generic rather than specific. The posterior spine on the protopod of the uropod is another feature probably of generic significance. While the post-larvae of Dardanus and Petrochirus differ from those of other diogenids in having many more segments on the antennular and antennal flagella and in having greater setation on appendages including pleopods, these differences might be a function of size. At any rate the number of such segments and the setation formulae appear to be specific. Presence of the ventral hooks on the am- bulatory dactyls seems to be a generic character but their orientation is apparently specific. Dechance and Forest (1958) were correct in their supposition that the glaucothoe of Petrochirus would be found to be very similar to that of Dardanus. Not only does it share the above mentioned features with Dar- danus but virtually all other characters which distinguish that genus from other diogenids. The glaucothoe of Petrochirus diogenes does not differ from those of Dardanus so far described in any character which may be considered at this time to be of generic significance. Even the presence of teeth on the postero-lateral comers of the telson is probably a specific character, for D. venosus shows very slight prominences there while the other Dardanus species have well-rounded comers.

SUMARIO Los GLAUCOTHOESDE Petrochirus diogenes (L.) Y DOSESPECIES DE Dardanus (DECAPODA:DIOGENIDAE) Los estados de post-zoea de tres cangrejos ermitafios: Dardanus scute/- latus del Padfico y dos formas de las Indias Occidentales, D. insignis y Petrochirus diogenes, son identificados y descritos en detalles. Se discuten caracteres de significaci6n espedfica y generica. Los glaucothoes de P. diogenes y varias especies de Dardanus son similares en los aspectos que los distinguen de los glaucothoes descritos de otros generos. Las diferencias entre los estados de post-zoea de P. diogenes y Dardanus sp. no son ma- yores que las diferencias entre especies de Dardanus. 1963] Provenzano: Glaucothoes of Diogenid Hermit Crabs 261 La comparaci6n del tamafio con el numero de setas del telson en cuat£O especies, indica que glaucothoes morfol6gicamente similares pueden ser diferenciados por este u ot£Os medios similares.

LITERATURE CITED

DECHANCE, M. AND J. FOREST 1958. Les glaucothoes de Catapaguroides timidus (Roux) et de Clibanarius erythropus (Latreille). Remarques sur Ie stade post-Iarvaire des Pagurides. Bul!. Soc. Zoo!. France, 83 (2-3): 274-293.

PROVENZANO, A. J. 1963. The glaucothoe stage of Dardanus venosus (H. Milne-Edwards) (Decapoda: ). BuLl. Mar. Sci. GuLf & Carib., 13 (1): 11-22, figs. 1-5.