DESCRIPTION OF A NEW SPECIES OF PETROLISTHES FROM THE WESTERN PACIFIC (DECAPODA, ANOMURA,...

A NEW SPECIES OF THE PETROLISTHES GALATHINUS COMPLEXFROM THE SOUTHERN CARIBBEAN SEA, WITH A DISCUSSION

ON THE IDENTITY OF P. GALATHINUS (BOSC, 1802)(DECAPODA, PORCELLANIDAE)

BY

BERND WERDING1/ and ALEXANDRA HILLER2/

Institut für Tierökologie und Spezielle Zoologie der Justus-Liebig-Universität Giessen,Heinrich-Buff-Ring29 (Tierhaus), D-35392 Giessen, Germany

ABSTRACT

A new species of porcellanid crab, Petrolisthes sanmartini is described. This new species anda second one, currently being described elsewhere, are additional members of the Petrolisthesgalathinus complex (Werding, 1983), which is now represented by six species in the southernCaribbean Sea. The new species is distinguishedmorphologically from all other comparable speciesby an exceptionally slender shape of the walking legs and the presence of � ve movable spines onthe dactylus of the walking legs, and can be distinguished in the � eld by its colouration as well. Theidentity of Petrolisthesgalathinus (Bosc) is discussed in relation to the new � ndings.

ZUSAMMENFASSUNG

Eine neue Porcellanidenart, Petrolisthes sanmartini wird beschrieben. Die neue Art und eineweitere, die zur Zeit zur Veröffentlichung vorbereitet wird, sind zusätzliche Mitglieder des Petrolis-thes galathinus Artenkomplexes (Werding, 1983), der nun mit sechs Arten im südlichen karibischenMeer vertreten ist. Die neue Art ist morphologischvon allen anderen vergleichbarenArten durch eineaußergewöhnlich schlanke Gestalt der Laufbeine und die Anwesenheit fünf beweglichen Stachelnam Dactylus der Laufbeine zu unterscheiden und kann im Feld durch ihre Färbung von verwandtenArten unterschieden werden. Die Identität von Petrolisthes galathinus (Bosc) wird im Zusammen-hang mit den neuen Funden diskutiert.

INTRODUCTION

The � rst to recognize the presence of different species similar to Petrolisthesgalathinus (Bosc, 1802) in the western Atlantic was Werding (1977), who sep-arated one species from similar specimens from Santa Marta, Colombia, by means

1/ e-mail: [email protected]/ e-mail: [email protected]

© Koninklijke Brill NV, Leiden, 2002 Crustaceana 75 (7): 849-857Also available online: www.brill.nl

850 BERND WERDING & ALEXANDRA HILLER

of a different colouration and the presence of a second epibranchial spine. Thisspecies, which proved to be more abundant on the Islas del Rosario, northernColombia, was later described as P. rosariensis Werding, 1982. P. rosariensis wassince found in tropical Brazil, Central America, and Cuba (Werding, 1992). In alater paper, Werding (1983) described two additional species, P. columbiensis andP. caribensis. Both species are most easily distinguishable from similar species bymeans of their typical colour pattern. P. columbiensis has been reported hithertoonly from the Islas del Rosario and from Cuba, whereas P. caribensis was reportedfrom Florida, through the Antilles to Panama and Colombia.

Recent collections of Porcellanidae on Islas del Rosario revealed a colourvariation, distinguishable from comparable species, consisting of a � ner stripedpattern and the longitudinally striped carpus and propodus of the walking legs.Later observations of the specimens revealed morphological features which areconstant and distinguish the new form from all other species of the P. galathinuscomplex, as described by Werding (1983).

The type specimens are deposited in the collection of the Instituto de Inves-tigaciones Marinas y Costeras, Santa Marta, Colombia (INVEMAR), the collec-tion of the Naturmuseum Senckenberg, Frankfurt a. M., Germany (SMF), and theNational Museum of Natural History, Smithsonian Institution, Washington D.C.,U.S.A. (USNM). The measurements refer to the maximum carapace length fol-lowed by maximum carapace width and are given in millimetres.

SYSTEMATICS

Family PORCELLANIDAE

Petrolisthes sanmartini sp. nov. (� gs. 1, 2, 3a-j)

Material. — Holotype: male, Colombia, Dept. Bolívar, Islas del Rosario, Isla San Martín, 2-3 m,in dead Porites porites (Pallas, 1766) formations, February 2001, leg. Werding. INVEMAR CRU3396.

Paratypes: 1 male INVEMAR CRU 3397, 3 females (1 ov.) INVEMAR CRU 3398; 2 males,3 females SMF 28171; 2 males, 2 females (1 ov.) USNM. All same data as holotype.

Measurements. — Largest male: 6.3 mm £ 5.9 mm; largest female 5.7 mm £5.3 mm; holotype 5.6 mm £ 5.3 mm.

Description. — Carapace as long as broad, evenly rounded along branchial mar-gins, broadest on midbranchial level; weakly convex front to back and transversely.Surface with strong transverse piliferous plications on gastric and branchial re-gions, interrupted by the cervical groove, regions well marked; a single strong epi-branchial spine present. Front sinuously triangular with a longitudinal depression,its borders fringed by a row of evenly set, upwardly directed blunt spines, which

PETROLISTHES SANMARTINI NOV. 851

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give them a serrated aspect; orbits moderately deep, supraocular spine strong, post-orbital angle produced into a spine-tipped tooth. Whole surface covered with smallfeathered, forwardly directed setae, arranged in lines along the transverse plica-tions, completely � attened down in the middle regions versus more upright behindand on the frontal region. Lateral borders fringed with feathered setae, lateral wallswith some longitudinal ridges. Third thoracic sternite convex posteriorly, trilobateanteriorly. Telson seven-plated with some short, transverse piliferous ridges.

Eyes moderately large, dorsal extension onto cornea narrow, eyestalks borderedwith feathered setae. Basal segment of antennulae with some transverse rugae,anterior margin with four teeth. First movable segment of antennae with a serrate,spine-tipped lamellar lobe; second and third segments lightly rugose, � agellumnaked. Ischium of third maxilliped broad, rounded, with transverse piliferousplications, laterodistal edge with a brush of feathered setae; merus triangular,merus and carpus plicated.

Chelipeds subequal, ischium rugose, with a strong forwardly directed spine ondistal ventral edge, partly visible from above; merus rugose with serrate, spine-tipped lobe on anterior margin, one forwardly directed spine on surface nearposterior margin, outer distal border armed with a prominent spine, followedinwards by a smaller one, dorsal face of merus with a pair of prominent, forwardlydirected spines in the middle of � exor margin; carpus two-and-a-half times as longas broad, armed on anterior margin with � ve broad, strong, serrate-edged teeth, the� fth forming the anterodistal edge; posterior margin straight, armed with seven toeight strong, inwardly curved spines, the last one forming a pair with an additionalspine on the distal border; surface evenly arched, covered with partly interruptedpiliferous striations; palm broad with an inconspicuous longitudinal ridge endingat the articulation of the dactylus, outer edge of the articulation with the dactyluswith a sharp upward-curved spine; outer margin of palm moderately convex, witha row of widely set, forwardly directed spines; surface of manus with striations,continuous on proximal inner portion and increasingly broken into series of shorterrugae distally and on � ngers, outer half densely covered with short, feathered setae.Chelipeds ventrally with similar striations as above, gape of the � ngers with anextended pubescence covering the proximal portions of pollex and dactylus, partlyvisible from above. Walking legs rugose; anterior margin of merus with a fringeof plumose setae, all segments covered with irregularly set, long simple setae;anterior margin in all legs with � ve, sometimes six spines; a large posterodistalspine on merus of legs 1 and 2, a smaller one on leg 3; carpus of leg 1 and 2with an anterodistal spine; propodus large and slender with a terminal triplet ofmovable spines on ventral border and two additional ones; dactylus large with � ve,sometimes six movable spinules on inner border.


Fig. 3. Petrolisthes sanmartini new species, young male, paratype INVEMAR No. xxxx. A, lateralview of carapace; B, anterior thoracic sternites; C, basal segment of left antennula; D, left thirdmaxilliped; E, left cheliped, ventral; F, right � rst walking leg, ventral; G, same as F, dorsal; H, right

second walking leg; I, right third walking leg; J, telson.

Colouration. — The new species is striped all over the carapace and thechelipeds show narrow and partly interrupted darker lines, which alternate with � newhitish ones. The darker stripes are beige-brown to olive-brown in light-colouredindividuals, and purplish in darker specimens. The rostrum is irregularly spotted,the line between the supraorbital spines is marked by a continuous, white ribbon.

The colours of merus and carpus of the cheliped are similar to those of thecarapace, but the striped pattern is more interrupted. The posterior margin of thecarpus bears a row of dark brown to purplish spots which are marking the bases ofthe marginal spines. Inner proximal portion of manus striped, otherwise spotted.Spines on posterior margin marked with similar spots as those on carpus.

Walking legs with irregular brown and olive patches on ischium and merus, thepatches may be overlaid by purple spots in darker specimens. Carpus, propodus,and dactylus whitish with narrow darker, longitudinal stripes. Antennulae almost


colourless; eyestalks and basal segments of antennae brown spotted; third maxil-lipeds colourless with the exception of � ne brown, longitudinal lines on the lon-gitudinal ridges of carpus and propodus, � ltering setae yellow. Ventral surface en-tirely beige and increasingly purplish in darker coloured specimens. The coloura-tion fades out within a few weeks when preserved in ethanol.

Habitat. — The new species was collected from the interstices of dead Poritesformations in depths between 2 and 3 m on the exposed reef of Isla San Martín,and, in one case, in coral debris at a depth of 4 m near Isla Grande. The speciesseems to prefer deeper and more exposed situations than the other species of theP. galathinus complex, which were sampled in the same localities.

Etymology. — The species name is derived from the type locality Isla SanMartín in the Islas del Rosario group.

Remarks. — Petrolisthes sanmartini is distinguished from all similar species,including an additional one, described elsewhere (Werding & Kraus, in prep.),by its slender extremities, what is especially noticeable in the large propodiof the walking legs, as well as in the presence of � ve movable spines on thedactylus of all walking legs, a character never described in other species of theP. galathinus complex or in any other western Atlantic porcellanid species. It seemsthat P. sanmartini occupies another ecological niche than do the other members ofthe group, since it was usually not found in the same samples as the remainingspecies of the complex. It seems to live in the deeper parts of the coral structureand to prefer deeper waters. The comparatively larger legs and the armature of thedactylus may indicate a greater mobility than in comparable species.

DISCUSSION

Petrolisthes galathinus was � rst described very super� cially by Bosc (1802) asPorcellana galathina. The name was given to the species because of the transversepiliferous ridges covering the carapace and the extremities, resembling those ofthe genus Galathea. Gibbes (1850) apparently described the same species asPorcellana sexspinosa and concluded later (Gibbes, 1854) that his species wassynonymous with Bosc’s species. He (Gibbes, 1854) gave a detailed descriptionof the species which, up to then, had been reported various times but withoutdetailed descriptions, and resumed the synonymy. He described the colourationas “red, more intense on the piliferous lines or rugae, the hairs grey or ash colour”.The origin of Bosc’s material is not known, but Gibbes (1854) suggests that theoriginal material might have proceeded from the southern Atlantic coast of theUnited States, since Bosc had resided for some time in Charleston as a consul,where he described various crustacean species from North America. Gibbes (1854)


recognized another species, P. danae, which had formerly been described byDana (1852) as P. boscii from the coast of Brazil. This species, however, hasbeen put into synonymy with P. galathinus by later authors (Haig, 1956). Allsubsequent authors (e.g., Benedict, 1901; Rathbun, 1900; Schmitt, 1935; Haig,1956; Williams, 1965; Coélho & Ramos, 1973; Gore, 1974; Rickner, 1975) treatedP. galathinus as one widespread species with a distribution throughout the westernAtlantic from North Carolina (U.S.A.) to Santa Catarina (Brazil). Various authorsrecognized the presence of different colour forms within P. galathinus. Benedict(1901) described, among specimens from Puerto Rico, one variety of a colourmuch like the description given by Gibbes (1854) but, in more detail, a secondone which is marked with a double white cross on the carapace. Rickner (1975)emphasized the considerable colour variation in specimens from the eastern coastof Mexico, and Williams (1984) cites different colour forms described by variousauthors. The species is a further member of the Petrolisthes galathinus complex inthe western Atlantic.

It remains unclear which is the true identity of Bosc’s P. galathinus, and alsowhat is the status of this species in the eastern Paci� c. Bosc’s (1802) quite crudesketch shows a transversely striped specimen, a pattern shown in P. galathinusspecimens from the eastern Paci� c (pers. obs.) and in most western Atlantic forms,except P. caribensis and P. rosariensis. As a consequence, we postulate as thetypical form of P. galathinus a morph exhibiting a striped colour pattern, bearingone epibranchial spine, a supraocular and an infraocular spine, and three movablespines on the dactylus of all walking legs. It is assumed that the geographical rangeof this form includes the southern coasts of North America, where Bosc’s originalmaterial was supposed to be found (Gibbes, 1854). The status of the eastern Paci� cform will have to be reconsidered in the context of the new � ndings.

ACKNOWLEDGEMENTS

We thank Rafael Vieira who hosted one of us (B.W.) in Isla San Martínand helped with many aspects of our work on the Islas del Rosario; we alsothank INVEMAR and its staff, especially Gabriel Navas, for cooperation andlogistic support. We are grateful to Helga Schmitt and Sandra Kalscheid for theelaboration of the � gures. Part of the work was co-� nanced by COLCIENCIAS(project cod 210509-10401) and INVEMAR-FONADE(administrative agreementNo. 001065). This is contribution No. 736 from INVEMAR.

LITERATURE CITED

BENEDICT, J. E., 1901. The anomuran collectionsmade by the Fish Hawk Expedition to Porto Rico.Bull. U.S. Fish. Comm., 20 (2): 129-148.


BOSC, L. A. G., [1801/] 1802. Histoire naturelle des Crustacés, contenant leur description et leursmœurs; avec � gures dessinées d’après nature, 1: 1-258, � gs. 1-8. (Paris).

COÉLHO, P. A. & M. DE ARAUJO RAMOS, 1973. A constituçao e a distribuçao de fauna dedecápodos do litoral leste da América do Sul entre as latitudes de 5±N e 39±S. Trab. oceanogr.Univ. fed. Pernambuco, Recife, 13: 133-236, � gs. 1-4. [1972]

DANA , J. D., 1852. United States Exploring Expedition during the years 1838, 1839, 1840,1841, 1842, under the command of Charles Wilkes. U.S.N., 13, Crustacea, 1 (8): 1-685.(Philadelphia).

GIBBES , L. R., 1850. On the carcinologicalcollections of the United States, and an enumeration ofspecies contained in them, with notes on the most remarkable, and descriptions of new species.Proc. American Assoc. Adv. Sci., 3: 167-201.

— —, 1854. Description,with � gures, of six species of Porcellana, inhabitingeastern coast of NorthAmerica. Proc. Elliott Soc. nat. Hist., 1: 6-13.

GORE , R. H., 1974. Biological results of the University of Miami Deep-Sea Expeditions, 102: on asmall collectionof porcellanidcrabs from the Caribbean Sea (Crustacea,Decapoda, Anomura).Bull. mar. Sci., 24 (3): 700-721, � gs. 1-5.

HAIG , J., 1956. The Galatheidea (Crustacea Anomura) of the Allan Hancock Atlantic Expeditionwith a review of the Porcellanidae of the western North Atlantic. Rep. Allan Hancock AtlanticExped., 8: 1-45.

RATHBUN, M. J., 1900. Results of the Branner-Agassiz Expedition to Brazil. I. The decapod andstomatopod Crustacea. Proc. Washington Acad. Sci., 2: 133-156.

RICKNER, A. A., 1975. Notes on members of the family Porcellanidae (Crustacea: Anomura)collected on the east coast of Mexico. Proc. biol. Soc. Washington, 88 (16): 159-166.

SCHMITT, W. L., 1935. Crustacea Macrura and Anomura of Porto Rico and the Virgin Islands.Scienti� c Survey of Porto Rico and the Virgin Islands, New York, 15 (2): 125-227, � gs. 1-80.

WERDING , B., 1977. Los porcelánidos (Crustacea, Anomura, Porcellanidae) de la región de SantaMarta, Colombia. An. Inst. Inv. Mar. Punta de Betín, 9: 173-214, � gs. 1-29.

— —, 1982. Porcellanid crabs of the Rosario Islands, Caribbean coast of Colombia, with adescription of Petrolisthes rosariensis new species (Crustacea: Anomura). Bull. mar. Sci., 32(2): 439-447, � gs.1-3.

— —, 1983. Der Petrolisthes galathinus-Artenkomplex im karibischen Raum mit Beschreibungvon P. caribensis n. sp. und P. columbiensis n. sp. (Crustacea: Anomura: Porcellanidae).Senckenbergiana biol., 63 (5/6): 407-418, � gs. 1-5. [1982]

— —, 1992. Beiträge zur Biologie, Ökologie und Biogeographie der amerikanischen Porzellanidae(Crustacea: Decapoda: Anomura) — Systematischer Anhang: 1-157. (Habilitationsschrift,Giessen).

WERDING , B. & H. KRAUS, in prep. A new species of the Petrolisthes galathinus complex fromthe southern Caribbean Sea (Crustacea: Decapoda: Porcellanidae).

W ILL IAMS , A. B., 1965. Marine decapod crustaceans of the Carolinas. Fish. Bull., U.S., 65 (1):1-298.

— —, 1984. Shrimps, lobsters, and crabs of the Atlantic coast of the eastern United States, Maine toFlorida: 1-550. (Smithsonian Institution Press, Washington, D.C.).

First received 4 October 2001.Final version accepted 16 January 2002.

DESCRIPTION OF A NEW SPECIES OF PETROLISTHES FROM THE WESTERN PACIFIC (DECAPODA, ANOMURA,...

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