Pteropagurus, Mclaughlin, Patsy A. & Rahayu, Dwi Listyo, 2006

Mclaughlin, Patsy A. & Rahayu, Dwi Listyo, 2006, A new genus with two new species of hermit crabs (Crustacea, Decapoda, Paguroidea, Paguridae) from an unique habitat, Zootaxa 1116, pp. 55-68 : 56-57

Pteropagurus n. gen.

Diagnosis. Eleven pairs of biserial phyllobranchiate gills. Rostrum triangular or reduced to broadly rounded lobe; lateral projections developed or obsolete. Ocular peduncles stout, corneas prominently dilated or not; ocular acicles triangular, each with small submarginal spine. Antennal peduncle with supernumerary segmentation. Mandible with entirely calcified cutting edge. Maxillule ( Fig. 2 e) with external lobe of endopod obsolete, internal lobe with 1 stiff bristle. Maxilla ( Fig. 2 f) with endopod considerably overreaching distal margin of scaphognathite. First maxilliped ( Fig. 2 g) with slender exopod. Second maxilliped without distinguishing characters. Third maxilliped ( Fig. 2 h) with crista dentata reduced, no accessory tooth. Sternite of third (thoracic somite IX of Pilgrim 1973) maxillipeds unarmed. Sternite of chelipeds (thoracic somite X) quite narrow, incompletely fused to larger sternite of second pereopods. Sternite of third pereopods (thoracic somite XII) sexually dimorphic ( Figs 2 b. 3b), very broad and prominently produced posteriorly in males, produced little if at all in females.

Chelipeds long, slender, right appreciably stouter, but not necessarily longer. Second pereopods distinctly shorter than third. Fourth pereopods semichelate or minutely chelate, propodal rasp with few scales. Fifth pereopods chelate, rasp moderately well developed.

Males with elongate, stout right sexual tube directed posteriorly and externally and curving up over anterior portion of pleon; very short left sexual tube; uniramous left pleopods 3–5. Females with paired gonopores or unpaired left; no paired and modified first pleopods, unpaired biramous left pleopods 2–4, pleopod 5 short, uniramous as in males. Pleon somewhat reduced, straight; pleomere 1 partially fused with last thoracic somite, tergites of pleomeres 2–5 weakly delineated; pleomere 6 chitinous. Uropods symmetrical; protopods each with posteriorly directed spine; exopods elongate, endopods reduced, both with 1 or 2 marginal rows of scales. Telson without transverse incisions, with slight median concavity or cleft in terminal midline, terminal margins rounded or oblique, unarmed or with few minute bristles.

Type species. Pteropagurus inermis n. sp., by present designation.

Etymology. The generic name is derived from the unique habitat of the pteropod mollusk shell utilized by the two species described herein; gender masculine

Distribution. New Caledonia; 285– 700 m.

Figures

FIGURE 2. Pteropagurus inermis n. sp., a – d, holotype ovig. female (sl = 1.6 mm) (MNHN Pg 7633), e – h, paratype male (sl = 1.3 mm) (MNHN Pg 7634). a, shield and cephalic appendages (aesthetascs omitted); b, sternites of second and third pereopods (thoracic sternites XI & XII) (ventral view); c, left fourth pereopod (lateral view); d, telson; e, right maxillule; f, right maxilla; g, right first maxilliped; h, right third maxilliped. Scales equal 0.5 mm.