Chinommatia bruuni Serene 1964, n. comb.
Creators: name: Ng, Peter K. L.
name: Castro, Peter
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Chasmocarcinidae
Chinommatia
Chinommatia bruuni

description: Chinommatia bruuni (Serène, 1964) n. comb.
(Figs. 14 G‒J; 25C, D; 32B; 43C, D; 53C; 60B; 75E‒I; 87E)
Hephthopelta bruuni Serène, 1964a: 248, fig. 17, pl. 22, fig. B [type localilty: Vietnam]; 1968: 92 [in list].—Ng et al. 2008: 76 [in list].
Type material (not examined). Holotype female (4.0 × 5.0 mm) (depository unknown), Vietnam, Nahtrang.
Other material examined. Malaysia. 2 males, larger (4.3 × 5.5 mm), 5 females, largest (5.5 × 7.2 mm) (ZRC 2013.0020), offshore Bintulu, northern Sarawak, stn F28 oilfield, T.S. Leong coll., 2000s.
Indonesia. 1 male (3.4 × 4.0 mm) (ZMUC CRU- 1524), Java Sea south of Borneo, GALATHEA EXPEDITION, 60 m.
Papua New Guinea. 1 male (6.5 × 5.1 mm) (USNM 1277740), HELIX-79, stn M-47, 06°41’54”S, 147°50’E, 5‒30 m, Alpha Helix, G. Hendler coll., 17.06.1979.
? Philippines. Mindanao, Coronado Bay, 1 female (cl 3.9 mm, carapace damaged) (WAM), PELE EXPEDITION, 46‒128 m, 10.02.1964.
Diagnosis. Carapace (Fig. 14 G‒J) subtrapezoidal, convex, 1.3 wider than long; front slightly bilobed; anterolateral margins slightly arcuate, pubescent, minutely granular with pointed tubercle in males. Eye peduncle (Fig. 25 C, D) filling orbit, thick, long, mobile; cornea reduced, with reduced pigmentation. Epistome (Fig. 25 C, D) with short, semicircular median lobe with deep median fissure; short, slightly semicircular lateral margins. Third maxilliped (Fig. 32 B) merus ovate, anteroexternal angle rounded, ischium rectangular, about same length as merus. Proportionally long ambulatory legs (Fig. 14 G‒J). Chelipeds (Figs. 14 G‒J; 43C, D) subequal in length, slightly dissimilar in females, heteromorphic in males; fingers of minor chela (Fig. 43 D) subcircular in cross-section, scissor-like, cutting margins with sharp teeth; most proximal teeth on cutting margin of major chela of males (Fig. 43 C) with short teeth of about same size. Ventral surface of cheliped merus with row of sharp tubercles. Inner margin of cheliped carpus with short tooth (Fig. 14 G‒J), posterior inner margin angular (Fig. 14 I, J). Fused thoracic sternites 1, 2 (Fig. 53 C) semicircular, broad, long. Male pleon (Figs. 53 C; 60B) with proportionally long telson, posterior portion of somite 3–5 proportionally narrow. G1 (Fig. 75 E‒G, I) slender, distal segment straight, with short spinules. G2 (Fig. 75 H) about 3/4 G1 length, curved, slender, distal segment short. Female telson (Fig. 87 E) proportionally long. Vulvae wide, located relatively close together on outer margins of cavity close to suture 5/6, visible when pleon not tightly closed.
Remarks. Chinommatia bruuni is an atypical member of the genus in that the posterior inner margin of the cheliped carpus is angular (Fig. 14 I, J) (rounded in congeners) and the vulvae are more laterally positioned such that they are visible when the pleon is not tightly closed (Fig. 87 E). In all other morphological aspects, notably the form of the gonopods, however, it agrees with the current definition of the genus so it is best placed in Chinommatia.
Serène (1964a: 184) noted that the holotype female (and his only) specimen of Hephthopelta bruuni was from the Gallardo Collection and not collected by the Th. Mortensen Expedition, and therefore not part of the ZMUC material. In his description of the species (Serène 1964a: 248–252, fig. 17, pl. 22B), he did not indicate where the specimen was from, the only data being “E. 43.764, Coll. Gallardo. St. 1542”. In his discussion of the genus, he fortunately recorded: “ H. bruuni nov. sp. (Nhatrang, Viet Nam)” (Serène 1964a: 240) so we know it is actually from Vietnam. He did not indicate the eventual depository of the holotype. It is not in ZMUC or MNHN. It is possible the specimen and was possibly returned to Gallardo or to some institution in Vietnam. Also inexplicable is the status of the small male specimen from Java, now in ZMUC (ZMUC CRU-1524). It had been identified by Serène and is part of the Mortensen Expedition material but was not mentioned in Serène (1964a). As such it is not a paratype.
A small, badly damaged female specimen without pereiopods from the Philippines (WAM) clearly belongs to Chinommatia (mobile, long eye peduncles and similar carapace shape with a row of tubercles along the anterolateral margin) is provisionally referred to C. bruuni. It lacks the small, pointed anterolateral tubercle present in a similarly sized male specimen of C. bruuni (3.4 × 4.0 mm, ZMUC CRU-1524).
Identification of the present male specimens from Java and Sarawak, east Malaysia with C. bruuni is based entirely on the figures by Serène (1964a), which are of the female holotype. Neither are we completely certain that the ZMUC specimen (from northern Java) is conspecific with the ZRC specimens from Sarawak. The G1 of the largest of the Malaysian males (4.3 × 5.5 mm, ZRC 2013.0020; Fig. 75 I) is similar to that of the Java male (3.4 × 4.0 mm, ZMUC CRU 1524; Fig. 75 E) except that the apex of the latter is more flared. While this may be a consequence of size differences, more material is certainly needed before firm conclusions can be drawn.
While their gonopods are very different, C. bruuni superficially resembles Notopelta mortenseni in its general carapace and pereiopodal features, especially when females are compared. Female specimens of N. mortenseni do not possess the characteristic long spur on the basis-ischium of minor cheliped. Male and female specimens of C.
bruuni, however, can still be distinguished by their proportionately less broad carapace (Fig. 14 G–J) (broader in N. mortenseni; Fig. 15 G, I), the denticular anterolateral margin is clearly marginal (Fig. 14 G–J) (submarginal in N. mortenseni; Fig. 15 G–I); the inner subdorsal margin of the chela is entire (Fig. 14 G, I, J) (with several distinct granules in N. mortenseni; Figs. 15 G, I, 45A); and the vulvae are proportionately smaller and more rounded (Fig. 87 E) (larger and ovate in N. mortenseni; Fig. 87 G).
Distribution. Western Pacific Ocean (Vietnam to Papua New Guinea; questionably Philippines). Depth: 5– 60 m.
description: Published as part of Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), pp. 1-182 in Zootaxa 4209 (1) on pages 66-70, DOI: 10.11646/zootaxa.4209.1.1, http://zenodo.org/record/272646