Alain raymondi, Ahyong, Shane T. & Ng, Peter K. L., 2008

Ahyong, Shane T. & Ng, Peter K. L., 2008, Alain raymondi, a new species of deepwater pinnotherid crab (Crustacea: Decapoda: Brachyura) from the Philippines, commensal with holothurians, Zootaxa 1919, pp. 61-68 : 62-67

publication ID	https://doi.org/ 10.5281/zenodo.184681
DOI	https://doi.org/10.5281/zenodo.6227743
persistent identifier	https://treatment.plazi.org/id/03BFC45D-6426-9753-68A7-F8E9E0D0EAB7
treatment provided by	Plazi
scientific name	Alain raymondi
status	sp. nov.

Treatment

Alain raymondi View in CoL sp. nov.

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Material examined. HOLOTYPE: NMCR, male (cl. 8.9 mm, cw. 10.1 mm), 9 o37.1 –36.7’N, 123 o44.5 – 42.9’E, 467–609 m, PANGLAO 2005, station CP2396, 31 May 2005. PARATYPES: ZRC, ovigerous female (cl. 10.2 mm, cw. 11.0 mm), 9°37.9–38.7’N, 123°44.9–45.4’E, 453–470 m, PANGLAO 2005, station CP2405, 1 June 2005; ZRC, 1 spent female (cl. 8.5 mm, cw. 9.3 mm) 9 o36.2 –36.7’N, 123 o43.8 –44.6’E, 434– 532 m, PANGLAO 2005, station CP2395, 31 May 2005; ZRC, 1 male (cl. 9.4 mm, cw. 10.7 mm), 1 spent female (cl. 9.6 mm, cw. 10.4 mm), 9 o27.4 –27.4’N, 123 o43.4 –42.9’E, 613–627 m, PANGLAO 2005, station CP2390, 30 May 2005; ZRC, 2 spent females (cl. 8.0, cw. 9.1; cl. 9.9 mm, cw. 10.4 mm), 9 o28.6 –29.1’N, 123 o40.0 –40.7’E, 566–787 m, PANGLAO 2005, station CP2394, 30 May 2005; ZRC 2008.0565, 2 immature females (cl. 7.6 mm, cw. 8.2 mm; cl. 7.9 mm, cw. 8.7 mm), 9°25.7–26.2’N, 123°32.8–34.0’E, 782–786 m, PANGLAO 2005, station CP2388, 30 May 2005; ZRC, male (cl. 6.8 mm, cw. 7.2 mm), 2 immature females (cl. 5.0, cw. 5.4; cl. 7.8 mm, cw. 8.7 mm) 9 o27.4 –27.4’N, 123 o37.6 –37.6’E, 786– 784 m, PANGLAO 2005, station CP2389, 30 May 2005.

Diagnosis. Maxilliped 3 dactylus not reaching apex of the propodus. Walking leg dactyli in males subequal.

Description. Males: Androgynous . Carapace slightly broader than long; surface setose, punctate; front slightly produced, anterior margin broadly convex.

Antennular sinus broader than orbit; antennules folded transversely. First 2 antennal segments fused to epistome. Eyes partially visible in dorsal view, filling orbit, cornea pigmented.

Maxilliped 3 ischiomerus width about 0.6 length; inner margin obtusely angled, proximally setose; outer margin strongly convex. Carpus shorter than propodus, setose. Propodus spatulate, longer than wide, gently tapering to blunt, setose apex. Dactylus digitiform, distally setose, inserted at proximal third, apex falling short of propodal apex. Exopod with convex inner and outer margins, sparsely setose; distal segment setose.

Chelipeds symmetrical. Dactylus and pollex relatively straight, crossing distally, occlusal margins crenulate distally, proximally with irregular, blunt projections; pollex with fringe of short setae on inner ventral margin. Propodus dorsal margin about 1.3 times longer than dactylus, and about 1.5 times height; ventral margin sinuous, concave at base of pollex. Carpus inner margin setose.

Walking legs similar in form, symmetrical from left to right, densely setose; relative lengths in decreasing order P3>P4>P2>P5. Dactyli subequal, setose; apices spiniform, corneous. P2 dactylus 0.6 propodus length; propodus length 2.6 height, 1.6 carpus length; merus length 3.0 height, 2.0 carpus length. P3 dactylus 0.6 propodus length; propodus length 3.0 height, 1.6 carpus length; merus length 3.2 height, 2.0 carpus length. P4 dactylus 0.6 propodus length; propodus length 3.0 height, 1.5 carpus length; merus length 3.3 height, 1.9 carpus length. P5 dactylus 0.9 propodus length; propodus length 2.4 height, 1.4 carpus length; merus length 3.1 height, 1.8 carpus length. G 1 in the form of a simple tube, distally fluted, apex subtruncate. G2 short, arising near base of poorly developed biramous pleopod of somite 3. Somites 4 and 5 with well-developed, uniramous pleopods. Female gonopores simple rounded; present on sternite 5 near junction with sternite 6.

Female: Carapace subglobular, slightly broader than long; surface setose, punctate; front slightly produced, anterior margin broadly convex.

Antennular sinus wider than orbit; antennules folded slightly obliquely. First 2 antennal segments fused to epistome. Eyes partially visible in dorsal view, filling orbit, cornea pigmented.

Maxilliped 3 ischiomerus about half as wide as long; inner margin obtusely angled, proximally setose; outer margin strongly convex. Carpus shorter than propodus, setose. Propodus spatulate, longer than wide, gently tapering to blunt, setose apex. Dactylus digitiform, distally setose, inserted at proximal third, apex falling short of propodal apex. Exopod with convex inner and outer margins, sparsely setose; flagellum 2-segmented, distal segment setose.

Chelipeds symmetrical. Dactylus and pollex relatively straight, crossing distally, occlusal margins crenulate distally, proximally with irregular, blunt projections; pollex with fringe of short setae on inner ventral margin. Propodus dorsal margin about 1.8 times longer than dactylus, ventral margin distinctly sinuous, concave at base of pollex. Carpus inner margin setose.

Walking legs similar in form, symmetrical from left to right, densely setose; relative lengths in decreasing order P3>P4>P2>P5. Dactyli similar, setose; apices spiniform, corneous; relative dactylus length P5>P4>P3>P2. P2 dactylus 0.6 propodus length; propodus length 2.8 height, 1.4 carpus length; merus length 3.5 height, 2.1 carpus length. P3 dactylus 0.6 propodus length; propodus length 2.8 height, 1.5 carpus length; merus length 3.8 height, 2.2 carpus length. P4 dactylus 0.7 propodus length; propodus length about 2.7 height, 1.6 carpus length; merus length 3.7 height, 2.2 carpus length. P5 dactylus as long as propodus; propodus length 2.8 height, 1.5 carpus length; merus length 3.1 height, 2.0 carpus length.

Abdomen widest at somite 5, covering bases of walking legs in mature specimens. Egg diameter 0.8 mm.

Size range. Male (n = 3) cl. 6.8–9.4 mm, cw. 7.2–10.7 mm; female (n = 9) cl. 5.0– 10.2 mm, cw. 5.4–11.0 mm.

Etymology. We are pleased to name this new species after our late friend, Ray Manning, who described Alain and its type species, A. crosnieri .

Distribution. Presently only known from the Philippines; 453– 787 m.

Remarks. Alain raymondi sp.nov., the second known species of the genus, differs from A. crosnieri in the length of the dactylus of maxilliped 3 (not reaching, rather than overreaching the apex of the propodus), and in the relative lengths of the walking leg dactyli in males (subequal, rather than having P2–3 dactyli shorter than the P4–5 dactyli). Known males of both species of Alain are androgynous and inhabit the intestine of deepwater holothurians. Several other pinnotherids are associates of holothurians (e.g., Ostracotheres holothuriensis ( Baker, 1907) , members of Buergeres Ng & Manning, 2003 , and Holothuriophilus Ng & Manning, 2003 ), but all occur in shallow water.

Knowledge of population structure of A. raymondi is limited to the three males and nine females of the type series. Following the general pattern of brachyuran development, juvenile crabs of both sexes have narrow male-form abdomens, which become wider with maturity in females. Thus, in general, protandry could be expected to be more likely than protogyny. However, that all the males of Alain raymondi are androgynous and the smallest known specimens are morphologically female (i.e., have female gonopores but no male gonopods) suggests that the species is possibly protogynous. The abdomen of the smallest juvenile females is narrow as in males, but in females of 7.9 mm carapace length or above, the abdomen is distinctly broader proportionally than in the largest males. Of the known specimens of A. crosnieri (four males, cl. 7.6–9.4 mm, cw. 8.3–10.6 mm; three females, cl. 8.2–11.7 mm, cw. 9.5–13.0 mm), the smallest is male, though only slightly smaller than the smallest female ( Manning 1998). Androgyny is rare in decapods and has been reported from only a few pinnotherids: Nepinnotheres androgynus Manning, 1993 b, A. crosnieri and now, A. raymondi . In addition, we take this opportunity to report the first known androgynous male of Pinnotheres novaezealandiae ( Filhol, 1885) , collected from Picton, New Zealand (cl. 4.5, cw. 4.6 mm, coll. 8 Dec 2005, NIWA (MITS) 1217). Following Manning’s (1993b) redefinition of Pinnotheres Bosc, 1802 , and the establishment of Nepinnotheres Manning, 1993 b (type species: Cancer pinnotheres Linnaeus, 1758 ), P. novaezelandiae is best accommodated in the latter genus because the maxilliped 3 dactylus articulates near the midlength instead of at the base of the propodus, and because of the subequal dactyli of the P2–4, with that of P5 slightly shorter. Filhol’s species is therefore transferred to Nepinnotheres as N. novaezealandiae . With Manning’s (1993b) restriction of Pinnotheres to species in which the third maxilliped dactylus articulates at the base of the propodus, many species previously placed there now correspond to Nepinnotheres or Arcotheres Manning, 1993 a. Most species currently assigned to Pinnotheres sensu lato will require restudy to determine their generic position. Nevertheless, the concept of Nepinnotheres itself requires further scrutiny, especially in relation to Viridotheres .

Androgyny in the Pinnotheridae is now known from four species in two genera. Most pinnotherid species are currently known only from adult females, and little is known of their biology. Androgyny as a phenomenon in pinnotherids warrants further study; it may be significantly more prevalent than currently recognized.