Catapaguropsis Lemaitre & McLaughlin, 2006

Mclaughlin, Patsy A. & Lemaitre, Rafael, 2007, A new and distinctive species of the hermit crab genus Catapaguropsis (Crustacea: Decapoda: Anomura: Paguridae) from the South China Sea, Zootaxa 1560, pp. 31-41 : 32-33

Catapaguropsis Lemaitre & McLaughlin, 2006 (emended)

Catapaguropsis Lemaitre & McLaughlin, 2006: 58 .

Diagnosis. Eleven pairs of biserial phyllobranchiate gills. Rostrum broadly subtriangular or reduced to broadly rounded lobe. Ocular peduncles with very slender penultimate segments, ultimate segments also slen- der proximately, but distally broadened, corneas prominently dilated; ocular acicles quite small, triangular. Antennal peduncles with supernumerary segmentation. Mandible with entirely calcified cutting edge except for small, corneous tooth at outer lower angle. Maxillule with external lobe of endopod rudimentary or vestigial. Maxilla with endopod exceeding distal margin of scaphognathite. First maxilliped with slender endopod exceeding distal margin of basial endite. Second maxilliped without distinguishing characters. Third maxilliped with crista dentata reduced or not, with accessory tooth. Sternite of third maxillipeds (thoracic somite IX of Pilgrim 1973) unarmed. Sternite of chelipeds (thoracic somite X) narrow, incompletely fused to larger sternite of second pereopods. Sternites of second and third pereopods (thoracic somites XI, XII) very broad, with distinct median concavities.

Chelipeds long, slender; right appreciably stouter, but not necessarily longer. Ambulatory legs sexually dimorphic or not; dactyls slender or somewhat blade-shaped. Fourth pereopods simple or semichelate, propodal rasp absent or consisting of single row of corneous scales; preungual process well developed. Fifth pereopods minutely chelate.

Males with short, stout right sexual tube directed toward exterior; very short left sexual tube or papilla; no paired or unpaired pleopods. Females with paired gonopores; no paired and modified first pleopods, unpaired biramous left pleopods 2–4, pleopod 5 absent. Pleon always reduced posteriorly in males, reduced or not in females. Symmetrical uropods reduced or not. Telson with transverse incisions weak or obsolete; posterior lobes separated by broad median concavity or by minute median cleft, unarmed or with few minute spinules.

Type species. Catapaguropsis queenslandica Lemaitre & McLaughlin, 2006 , by original designation.

Distribution. Queensland, Australia and South China Sea; 296– 388 m.

Remarks. The new species, described below, is clearly assignable to Catapaguropsis on the basis of male characters: sexual tube, absence of male pleopods, shape and reduction of the male pleon, symmetrical uropods, which are also markedly reduced in males, but differs from the type species in female characters. Of the similarities with the genus Catapagurus observable in the female of Catapaguropsis queenslandica , which include ambulatory legs with blade-shaped dactyls, ambulatory meri each with one or more subdistal spines on the dorsal surface, and the tendency for loss of the left fifth pleopod, only the latter loss is seen in the female of C. brucei n. sp.

In the male of C. queenslandica , as in both sexes of species of Pteropagurus McLaughlin & Rahayu, 2006 , the third pereopods are markedly longer than the second. This dimorphism in C. brucei n. sp. is uncertain because only a single second right pereopod remains with the male paratype. Females of both Catapaguropsis species have ambulatory legs of generally equal length. The dimorphism in the fourth pereopods seen in C. queenslandica is not present in C. brucei n. sp.; both sexes have simple propodi, lacking propodal rasps. In Catapaguropsis , as in Pteropagurus , the sternite of the third pereopods is noticeably broadened. This was thought to also be a dimorphic character in Pteropagurus ; however, the posterior extension observed in males of P. inermis McLaughlin & Rahayu, 2006 and P. s p i n a McLaughlin & Rahayu, 2006 was found to occur in both sexes in a third recently discovered species (McLaughlin, in press).

Certain inaccuracies in the original generic description of the mouthparts of C. queenslandica are corrected based on a reexamination of the female paratype and on the morphology of the new species. The maxillule was illustrated ( Lemaitre & McLaughlin 2006: fig. 2B) as having a bilobed coxal endite; but reexamination of the maxillule has shown this condition to be an artifact. The coxal endite of the the maxillule of C. queenslandica and the new species is represented by a single lobe as is typical for paguroids in general. Similarly, the three-segmented exopods of the second and third maxillipeds (ibid.: fig. 2E, F) are artifacts; the exopods are two segmented as in most pagurids. The basis and ischium of the third maxilliped were illustrated (ibid.: fig. 2F) as being completely fused, and the crista dentata was described as lacking an accessory tooth. In the new species, when viewed externally, the basis and ischium similarly appeared to be completely fused, but internally, a suture line was visible. Reexamination has shown this also to be the case for C. queenslandica , indicating the basis and ischium must be considered incompletely fused. The crista dentata in the new species, when viewed externally, consisted of a row of translucent teeth decreasing in size anteriorly, but with one appreciably larger subdistal tooth. However, the internal view of the ischium showed that the crista dentata actually consisted of all small teeth distally and an adjacent subdistal large accessory tooth. The maxillule and second and third maxillipeds of C. queenslandica are herein illustrated accurately ( Fig. 2 a–c). The absence of an accessory tooth as a character that will distinguish Catapaguropsis from Catapagurus is not correct. Both genera have an accessory tooth on the crista dentata.

Figures

FIGURE 2. Catapaguropsis queenslandica Lemaitre & McLaughlin, 2006, a – c, paratype ovigerous female (sl = 1.9 mm) (QM W 16589), left mouthparts (internal view): a, maxillule; b, second maxilliped; c, exopod, and basis to ischium of third maxilliped. Catapaguropsis brucei n. sp., d, e, g, paratype male (sl = 2.7 mm) (MNHN Pg 7736); f, holotype ovigerous female (sl = 2.4 mm) (MNHN Pg 7735): d, thoracic sternites (thoracic somites X – XIV), coxae of pereopods 1 – 5, and sexual tubes (ventral view); e, sternite of fifth pereopods (thoracic somite XIV), and coxae with sexual tubes (ventral view); f, g, telson and uropods. Scales equal 0.25 mm (a, b, d – f), and 0.5 mm (c).