Buergeres Ng & Manning 2003
Creators: name: Ahyong, Shane T.
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Pinnotheridae
Buergeres

description: Buergeres sp.
(Fig. 5)
Material examined. ZRC 2018.0784, 1 male (cl 5.3 mm, cw 5.6 mm), Manga Point, Bohol, Visayas, Philippines, 09°42.1’N, 123°51.3’E, 0–1 m, mangrove and mixed intertidal habitat, from Holothuria impatiens, PANGLAO 2004 stn M24, 17 June 2004.
Description. MALE: Carapace rounded, high, vaulted, slightly wider than long, widest near midlength. Front produced, anterior margin concave in dorsal view. Anterolateral margins poorly defined. Dorsum smooth, glabrous, regions scarcely indicated centrally; dorsal midline convex in profile. Epistome with narrow triangular interantennular septum; median buccal margin with obtuse, triangular median point. Antennular sinus of slightly larger than orbit; antennules folded slightly obliquely. Antennal articles 1 and 2 fused to epistome. Eyes visible in dorsal view, filling orbit, cornea pigmented.
Maxilliped 3 ischiomerus length twice width; inner proximal margin convex; inner margin with blunt, obtuse angle slightly distal to midlength, margin on either side weakly concave; outer margin strongly convex. Carpus half propodus length. Propodus spatulate, gently tapering in distal half, apex rounded, dorsally and distally setose, length exceeding twice dactylus length. Dactylus sub-clavate, widest distal to midlength, apex rounded, distally setose, inserted at propodal midlength, apex not reaching end of propodus. Exopod inner margin straight, outer margin convex; flagellum with 2 articles, distally setose.
Chelipeds symmetrical from left to right. Dactylus and pollex relatively straight, crossing distally, without gape. Dactylus dorsal margin convex, smooth, glabrous; occlusal margin with blunt triangular tooth proximal to midlength, otherwise straight, sparsely setose. Pollex occlusal margin with 2 blunt triangular teeth proximally, remaining margin weakly crenulate, straight, sparsely setose, minutely denticulate; with fringe of setae on inner ventral margin extending onto lower inner palm surface. Propodus palm outer surface smooth, glabrous; dorsal margin 1.3× height, 1.1× length of dactylus; ventral margin sinuous. Carpus unarmed, inner margin setose.
Pereopods 2–5 (walking legs 1–4) symmetrical from left to right, unarmed; relative lengths in decreasing order: P3 = P4> P2> P5. P3 merus length 0.5× pcl. P2–4 similar; merus extensor margin broadly convex, extensor and flexor margins sparsely setose; carpus glabrous; dactylus and propodus flexor margins setose; dactyli subequal, stout, falcate, evenly arcuate, distally spiniform, length 0.4× propodus length; basis anterior surface smooth, not granulate. P5 merus tapering distally, distinctly shorter than P2–4 merus, extensor and flexor margins margins straight; propodus margins parallel, flexor margin setose; dactylus slender, weakly curved, almost straight, flexor margin setose but unarmed, 0.8× propodus length, 1.3× P2–4 dactylus length.
Thoracic sternum anterior margin concave medially; sternites 1–3 indistinguishably fused; sterno-pleonal cavity reaching level of sternite 3/4 suture.
Pleon slender, margins evenly converging distally; comprising 6 free somites and telson, widest at somites 1–3; telson as wide as long, apex rounded.
Gonopod 1 elongate, slender, gently arcuate, dorsoventrally compressed, about ¾ length of pleon, tapering to convex apex with short, obliquely directed spiniform tip; margins strongly setose. Gonopod 2 endopod simple, about ¼ length of gonopod 1; exopod short, slender, about half length of endopod. Pleopods 3–5 absent.
Host. Holothuria impatiens (Forskål, 1775) (Holothuriidae).
Remarks. Prior to the present study, knowledge of male Buergeres has been derived from a single specimen of B. deccanensis reported by Chopra (1931) (although without figures or description of the gonopods). We report here a male of an unidentified species of Buergeres from the Philippines (Fig. 5). It corresponds well to Buergeres in maxilliped 3 morphology and in the subequal P2–4 dactyli that are all shorter and more strongly curved than the straight, elongate P5 dactylus. Based on what is known of B. deccanensis, the P5 dactylus is essentially straight in both sexes, but proportionally shorter in males; the present male reflects such a condition. The Philippine male differs from male B. deccanensis in carapace shape (rounded versus subquadrate), and given the locality, might be referable to either B. holothuriae or B. ortmanni, both of which occur in the Philippines (Bürger 1895; Ng & Man- ning 2003). The specific identity of the male cannot be confirmed at present because it was not associated with a known female, but we believe that it is probably B. ortmanni: the outer surface of the cheliped palm is glabrous as in female B. ortmanni (Fig. 5D; Ng & Manning 2003: fig. 4C), rather than tomentose as in female B. holothuriae (Ng & Manning 2003: fig. 5D). Despite the unconfirmed identification, the present male is figured here to document its morphology, especially that of the gonopods. As in known males of Holotheres (see Ng & Manning 2003: fig. 1I, 2H), the G1 of the present male is broadly curved, with a short, slender, obliquely directed apex (albeit proportionally shorter than in Holotheres) (Fig. 5L). As in many other pinnotherids, the G2 of the male Buergeres has a short but distinct exopod (Fig. 5M, N; Ahyong et al. 2012; Ng & Ho 2016a; Ng 2018b; Ahyong 2019).
description: Published as part of Ahyong, Shane T. & Ng, Peter K. L., 2020, New species of pinnotherid crabs from Southeast Asia and Papua New Guinea (Crustacea: Decapoda: Brachyura), pp. 333-349 in Zootaxa 4816 (3) on page 341, DOI: 10.11646/zootaxa.4816.3.4, http://zenodo.org/record/3954447