Crosnierius carinatus Serène & Vadon, 1981

Mendoza, Jose Christopher E. & Ng, Peter K. L., 2010, The Euxanthine Crabs (Crustacea: Brachyura: Xanthidae) Of The Philippines, Raffles Bulletin of Zoology 58 (1), pp. 57-74 : 61

Crosnierius carinatus Serène & Vadon, 1981

( Fig. 1B )

Crosnierius carinatus Serène & Vadon, 1981: 131 , Figs. 1 , 2c, d , Pl. 3 Fig. C.

Material examined. – 1 male, 19.5 × 15.0 mm (NMCR-27332), Stn. CP 2349, off Pamilacan Is., 219–240 m, 9°31.6'N 123°55.7'E, Bohol Sea, coll. MV DA-BFAR, PANGLAO 2005 Deep-Sea Cruise , 24 May 2005 ; 1 female, 12.1 × 9.2 mm ( ZRC 2008.1368 ), Stn. CP 2348, off Pamilacan Is., 196–216 m, 9°29.6'N 123°52.5'E, Bohol Sea, coll. MV DA-BFAR, PANGLAO 2005 Deep-Sea Cruise , 24 May 2005 ; 1 female, 12.3 × 9.4 mm ( ZRC 2008.1369 ) , 1 male, 12.7 × 9.8 mm, 1 female, 10.9 × 8.6 mm ( MNHN-B30701 ), Stn. CP 2407, Maribojoc Bay, 256–258 m, 9°41.3'N 123°48.5'E, Bohol Sea, coll. MV DA-BFAR, PANGLAO 2005 Deep-Sea Cruise , 01 Jun.2005 ; 1 female, 15.6 × 11.8 mm ( ZRC 2008.1370 ), Stn. CP 2737, 269– 272 m, 16°01.91'N 121°59.23'E, off the eastern coast of Luzon, coll. MV DA-BFAR, AURORA 2007 Deep-Sea Cruise , 01 Jun.2007 .

Comparative material. – Crosnierius gracilipes Ng & Chen, 2005 : Holotype male, 9.1 × 7.0 mm ( ZRC 2005.0015 ), Stn. 6080, South China Sea, near Hong Kong, coll. 2 Apr.1959.

Remarks. – The genus Crosnierius contains two species, C. carinatus , the type species, and C. gracilipes Ng & Chen, 2005 , which is known only by the male holotype, collected near Hong Kong in the South China Sea. Crosnierius carinatus is thus far known only from the Philippines, with this report being only the second record for this species since it was first described. The recently collected Philippine specimens agree well with the description and figures of Serène & Vadon (1981). The largest male in this series (19.5 × 15.0 mm) is considerably larger than the male holotype (13.0 × 9.0 mm). In life, the carapace and pereopods are a uniform reddish-orange, sometimes with whitish mottling on the central portions of the carapace and on the meri of the ambulatory legs, especially in female specimens. Ng & Chen (2005) commented that they could not locate the type specimens in the MNHN. A fresh search by the authors as well as the collections manager was also unsuccessful (R. Cleva, pers. comm.).

In their comparison of Crosnierius gracilipes with illustrations of the holotype of C. carinatus, Ng & Chen (2005) noted the following differences: 1) the ambulatory legs (last ambulatory leg, P5) are longer and more slender in C. gracilipes than in C. carinatus , particularly with regard to the merus and propodus; 2) the spines on the anterior margin of the merus of P5 are more widely spaced apart in C. gracilipes ; 3) the anterolateral teeth are lower in C. gracilipes ; and 4) the dilated median part of the G1 is subequal in length to the spinulated distal one-third in C. gracilipes (vs. distinctly shorter in C. carinatus ). We compared the holotype of C. gracilipes with similarly sized C. carinatus specimens at hand and made the following observations. The ambulatory legs of C. gracilipes are slightly longer and more slender than those of C. carinatus , with the merus of P5 extending past the tip of the last anterolateral tooth when the leg is folded against the posterolateral carapace margin. In C. carinatus the distal tip of the merus just touches the tip of the last anterolateral tooth, in smaller specimens, or does not reach the tip, in the case of larger specimens. The teeth on the anterior edge of P5 are indeed spaced more widely apart in C. gracilipes due to their smaller size. In C. carinatus , these are larger and longer. Also, the spinulose terminal portion of the G1 is also relatively shorter in C. gracilipes . However, we do not agree with Ng & Chen’s (2005) assessment that the anterolateral teeth are lower and that the propodus of P5 is longer in C. gracilipes , these resulting from the manner in which the holotype of C. carinatus was photographed, making the structures appear different. Aside from the differences between C. gracilipes and C carinatus mentioned by Ng & Chen (2005), the following were also noted: 1) the dorso-external surface of the cheliped carpus is smooth and inflated in C. gracilipes (vs. eroded in C. carinatus ); 2) the external surface of the palm in both chelipeds is smooth in C. gracilipes (vs. external surface with an additional, weak, irregular keel near the upper margin in C. carinatus ; and 3) there is no distinct keel on the dorsal surface of the carpus of the ambulatory legs in C. gracilipes (vs. present in C. carinatus ). As such, we continue to recognize C. gracilipes as distinct from C. carinatus .

Figures

Fig. 1. Live colouration of euxanthine crabs from the Philippines: A, Cranaothus deforgesi Ng, 1993, male (8.0 × 5.9 mm) (R59, Panglao Is., ZRC 2008.1365); B, Crosnierius carinatus Serène & Vadon, 1981, female (15.6 × 11.8 mm) (CP2737, eastern coast of Luzon, ZRC 2008.1370); C, Epistocavea mururoa Davie, 1993, male (33.2 × 23.5 mm) (L36, Panglao Is., ZRC 2008.1371); D, Euxanthus herdmani Laurie, 1906, male (10.0 by 7.6 mm) (S32, Panglao Is., NMCR-27334); E) Euxanthus huonii (Hombron & Jacquinot, 1846), male (31.9 × 21.9 mm) (M17, Panglao Is., ZRC 2008.1376); F, Hepatoporus orientalis (Sakai, 1935) male (8.1 × 6.0 mm) (CP2862, off Batangas coast, ZRC 2008.1379).

Fig. 2. Live colouration of euxanthine crabs from the Philippines: A, Hypocolpus haanii Rathbun, 1909, male juv., (11.5 × 8.0 mm) (B11, Pamilacan Is., ZRC 2008.1383); B, Ladomedaeus fungillus Manuel-Santos & Ng, 2007, male juv. (9.7 × 7.0 mm) (CP2708, ZRC 2008.1389); C, Miersiella cavifrons Takeda, 1989, male (9.8 × 6.6 mm) (L36, Panglao Is., ZRC 2008.1391); D, Paramedaeus globosus Serène & Vadon, 1981, male (6.0 × 4.6 mm) (T36, Cervera Shoal, MNHN-B31891); E, Paramedaeus simplex (A. Milne-Edwards, 1873), female (9.7 × 6.8 mm) (S7, Panglao Is., NMCR-27356); F, Paraxanthodes obtusidens (Sakai, 1965), male (18.6 × 13.0 mm) (CP2747, ZRC 2008.1410).