Catapaguropsis, Lemaitre, Rafael & Mclaughlin, Patsy A., 2006

Lemaitre, Rafael & Mclaughlin, Patsy A., 2006, A new genus and species of the hermit crab family Paguridae (Crustacea: Decapoda: Anomura: Paguroidea) from Australia, Zootaxa 1297, pp. 57-68 : 58-59

Catapaguropsis n. gen.

Diagnosis. Eleven pairs of biserial phyllobranchiate gills. Rostrum broadly subtriangular or reduced to broadly rounded lobe; lateral projections moderately well developed. Ocular peduncles stout, corneas prominently dilated; ocular acicles triangular, each often with small submarginal spine. Antennal peduncle with supernumerary segmentation. Mandible ( Fig. 2 A) with entirely calcified cutting edge except for small, corneous blunt tooth at outer lower angle. Maxillule ( Fig. 2 B) with external lobe of endopod rudimentary or vestigial, internal lobe with long distal seta. Maxilla ( Fig. 2 C) with endopod exceeding distal margin of scaphognathite. First maxilliped ( Fig. 2 D) with slender endopod exceeding distal margin of basial endite. Second maxilliped without distinguishing characters. Third maxilliped ( Fig. 2 F) with crista dentata reduced, no accessory tooth. Sternite of third maxillipeds (thoracic somite IX of Pilgrim 1973) unarmed. Sternite of chelipeds (thoracic somite X) quite 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; second pereopods distinctly shorter than third in male, dactyls slender; second and third pereopods approximately equal in females, dactyls somewhat blade­shaped. Fourth pereopods in males simple, propodal rasp absent; fourth pereopods in females semichelate, propodal rasp with single row of scales; preungual process elongate and setose in both males and females. Fifth pereopods minutely chelate.

Males with short, stout right sexual tube directed externally; very short left sexual tube; no unpaired pleopods. Females with paired gonopores; no paired and modified first pleopods, unpaired biramous left pleopods 2–4, pleopod 5 absent. Pleon reduced in males. Uropods symmetrical. Telson with weak transverse incisions; posterior lobes separated by broad median concavity, unarmed or with few minute spinules.

Type species. Catapaguropsis queenslandica n. sp., by present designation.

Etymology. The generic name is derived from Catapagurus , with the Greek ending opsis meaning like or relating to appearance and reflecting the similarity of the new genus to Catapagurus ; gender feminine.

Distribution. Queensland, Australia; 296– 303 m.

Remarks. Similarities with the genus Catapagurus are manifest primarily in the female, and include ambulatory legs with blade­shaped dactyls, ambulatory meri each with one or more subdistal spines on the dorsal surface, and the tendency for loss of the left fifth pleopod. Also, both the new genus and Catapagurus have a preungual process on the fourth pereopod. However, the absence of an accessory tooth on the crista dentata will immediately distinguish females of Catapaguropsis from Catapagurus .

It is not unusual in pagurids for the left or right second and/or third pereopods to be slightly longer than its member pair, but in Catapaguropsis , as in Pteropagurus McLaughlin & Rahayu, 2006 , the third pereopods are markedly longer than the second. However, this difference is restricted to males in Catapaguropsis ; females have ambulatory legs of generally equal length. Similarly, dimorphism in the fourth pereopods has been reported in certain species of Pagurus ( Rahayu & Komai 2000, Komai & Osawa 2001, Komai & Rahayu 2004) but these differences relate to size and setation from left to right, and do not appear influenced by animal size or sex. In Catapaguropsis , differences in the structure and rasp development are sex related as noted in the species description. In Catapaguropsis , as in Pteropagurus , the sternite of the third pereopods is noticeably broadened, but in males of Pteropagurus , it is also dimorphic in its posterior extension. No dimorphism is seen in this sternite in Catapaguropsis . The two genera also share small body size, elongate chelipeds and ambulatory legs, absence of male pleopods, and symmetrical uropods.

Figures

FIGURE 2. Catapaguropsis queenslandica n. gen. and n. sp., paratype ovig. female (sl = 1.9 mm) (W 16589). Left mouthparts (internal view). A, mandible incisor process and palp; B, maxillule; C, maxilla; D, first maxilliped; E, second maxilliped; F, third maxilliped. Scales equal 1 mm (A – D), and 0.5 mm (E, F).