Oxypleurodon christiani, Forges, Bertrand Richer De & Corbari, Laure, 2012

Forges, Bertrand Richer De & Corbari, Laure, 2012, A new species of Oxypleurodon Miers, 1886 (Crustacea, Brachyura, Majoidea) from the Bismarck Sea, Papua New Guinea, Zootaxa 3320, pp. 56-60 : 57-59

publication ID

https://doi.org/ 10.5281/zenodo.281183

DOI

https://doi.org/10.5281/zenodo.6179890

persistent identifier

https://treatment.plazi.org/id/03DC8788-D40C-9E1B-FF45-A5C4FB07C627

treatment provided by

Plazi

scientific name

Oxypleurodon christiani
status

sp. nov.

Oxypleurodon christiani View in CoL n. sp.

Figs 1 View FIGURE 1 A–C; 2 A, B; 2 A.

Material examined: Papua New Guinea, Bismarck Sea, west of New Hanover I., BIOPAPUA, stn. CP 3653, 02 °13' S - 150°23' E, 680–700 m, 28/08/2010: male holotype 18.5 x 12.6 mm (MNHN-IU-2011-3891) S. Samadi & L. Corbari coll.

Diagnosis: Carapace triangular. Rostrum composed of 2 flattened, ear-shaped horns which are closely clustered. Carapace with raised plates arranged as follows: 2 semicircular supraocular plates; 1 gastric plate composed of 2 parts, long slender anterior gastric part connected with small posterior transverse part; 1 cardiac plate regularly curved, connected to posterior border of carapace, forming typically mushroom-shaped structure; 2 large branchial plates fused with 2 hepatic plates ( Fig. 1 View FIGURE 1 A, 2A); branchial plate with deep notch on interior side ( Fig. 1 View FIGURE 1 ).

Eyes small with dark, round cornea, protected by anterior part of hepatic plate. Antennae very short. Antennules inserted inside fossae. Quadrangular buccal frame closed by third maxillipeds. Thoracic sternal sutures with deep obliquely transverse grooves ( Fig. 1 View FIGURE 1 B). Chelipeds inflated, with smooth surface, sharp fingers. Ambulatory legs with articles cylindrical in cross-section; dactyli long, curved, sharp. Second pereopod subequal in length to cheliped.

Male abdomen with seven somites, including telson. First male gonopod almost straight, flattened apically ( Fig. 2 View FIGURE 2 A–B).

Live specimen orange-red.

Etymology: The species is dedicated to Christian Fitialeata, a sailor of the R.V. Alis, a good man and esteemed colleague who suddenly passed away in Rabaul under unfortunate circumstances during the BIOPAPUA cruise.

Remarks: Oxypleurodon christiani n. sp. belongs to the Oxypleurodon group of species which has short flattened rostral spines ( Fig. 3 View FIGURE 3 ). The other species in this group are O. auritum (Rathbun, 1916) , O. boholense Richer de Forges & Ng, 2009, and O. barazeri Richer de Forges & Ng, 2009.

Oxypleurodon christiani n. sp. is easily distinguishable from O. barazeri , where the carapace is more rounded with less marked dorsal plates less marked than in the new species ( Fig. 3 View FIGURE 3 A versus Fig. 3 View FIGURE 3 D) (Richer de Forges & Ng 2009: 252, fig. 3C). The main difference between O. christiani n. sp. and O. boholense is in the rostrum, which has sharp, diverging spines in O. boholense ( Fig. 3 View FIGURE 3 C) (Ng et al. 2008: 107, fig. 88; Richer de Forges & Ng 2009: 252, fig. 3D) but rounded and clustered spines in O. christiani n. sp. ( Fig. 3 View FIGURE 3 A). In O. christiani n. sp., the large cardiac plate is fused with the intestinal plate, forming a mushroom-shaped structure, in contrast to O. boholense where there are only a few marked intestinal plates ( Fig. 3 View FIGURE 3 C). The long branchial plate is separated from the hepatic plate by a deep gap in O. boholense , whereas these two plates are completely fused in O. christiani n. sp. ( Fig. 1 View FIGURE 1 C).

Oxypleurodon christiani View in CoL n. sp. seems to be closest morphologically to O. auritum View in CoL because the flattened rounded spines of the rostrum are similar ( Fig. 3 View FIGURE 3 B) ( Griffin 1976: 211, fig. 10b; Takeda & Nagai 1979; Richer de Forges & Ng 2009: 252, fig. 3B). The differences, however, are obvious. In O. auritum View in CoL , the carapace is pyriform, with a rounded branchial region ( Fig. 3 View FIGURE 3 B) while the carapace is more triangular, with the branchial plate forming an acute angle in O. christiani View in CoL n. sp. ( Fig. 1 View FIGURE 1 A; 3A). The supraocular plate is also relatively larger in O. auritum View in CoL than in O. christiani View in CoL n. sp. ( Fig. 3 View FIGURE 3 B versus Fig. 3 View FIGURE 3 A). The mediogastric plate is oblong in O. christiani View in CoL n. sp. ( Fig. 3 View FIGURE 3 A) but posteriorly enlarged in O. auritum View in CoL ( Fig. 3 View FIGURE 3 B). The branchial and hepatic plates just touch each other in O. auritum View in CoL whereas they are completely fused in O. christiani View in CoL n. sp. Oxypleurodon christani n. sp. was first figured (but unnamed) on the color poster published by Tin-Yam Chan (National Taiwan Ocean University, Keelung) under the title " Papua New Guinea deep-sea crustaceans revealed by the survey of the BIOPAPUA cruise".

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