Thursday, September 15, 2016

[Crustacea • 2016] Yuebeipotamon calciatile • A New Genus and New Species of Freshwater Crab (Decapoda, Brachyura, Potamidae) from southern China

Yuebeipotamon calciatile  
Huang, Shih & Mao, 2016

A new genus and species of freshwater crab, Yuebeipotamon calciatile gen. n., sp. n., is described from southern China. While the carapace features are superficially similar to species of Sinopotamon Bott, 1967, Longpotamon Shih, Huang & Ng, 2016, and Tenuilapotamon Dai, Song, Li, Chen, Wang & Hu, 1984, the new genus possesses a distinctive combination of carapace, ambulatory leg, male thoracic sternal, male abdominal, and gonopodal characters that distinguish it from these and other genera. Molecular evidence derived from the mitochondrial 16S rDNA supports the establishment of a new genus.

Keywords: China, freshwater crabs, new genus, new species, Potamidae, systematics, Yuebeipotamon calciatile, 16S rDNA

Figure 1. Yuebeipotamon calciatile gen. n., sp. n., color in life.
A male, specimen not collected B a limestone hill stream at the type locality.
Family Potamidae Ortmann, 1896

Yuebeipotamon gen. n.

Diagnosis: Carapace subquadrate, with dorsal surface slightly convex, surface generally smooth, rugose on anterolateral regions (Fig. 2A); postorbital and epigastric cristae distinct, not confluent (Fig. 2A); external orbital angle sharply triangular, separated from anterolateral margin by a narrow gap (Fig. 2A, B); median lobe of posterior margin of epistome sharply triangular (Fig. 2B); third maxilliped with relatively broad ischium, exopod of third maxilliped reaches beyond anterior edge of ischium, with short flagellum (Fig. 3D); male abdomen triangular, with short triangular telson (Fig. 2C); G1 generally slender, terminal segment large, elongated, with subbasal flap (Figs 2D, 3B, C); basal segment of G2 subquadrate (Fig. 3A).

Type species: Yuebeipotamon calciatile sp. n., by monotypy.

Etymology: The genus name is derived from the Chinese spelling system “Yue Bei”, which means northern Guangdong, for the locality of this genus. The suffix “Potamon” refers to the type genus of the family Potamidae, Potamon. Gender of genus neuter.

Figure 2. Yuebeipotamon calciatile gen. n., sp. n., male holotype (32.4 × 27.0 mm) (SYSBM 001294).
A dorsal view B frontal view of carapace C ventral view showing anterior thoracic sternum and abdomen D ventral view showing sterno-abdominal cavity with right G1 in situ (left G1 removed).

Etymology: The species name, “calciatile”, means living on limestone, relating to its natural habitat.

Color: Carapace is usually maroon to dark brown, while chelipeds and ambulatory legs are reddish to purplish in life (Fig. 1A).

Ecology: This primarily aquatic species is found in the pools of limestone hill streams where they hide in crevices. Almost each pool was occupied by at least one crab at the type locality, which is a relatively high density of distribution. Its slender legs indicate that this species has good climbing abilities and mobility on land. These abilities are assumed to be advantageous in the volatile and short-lived nature of limestone hill streams, which may force them to intermittently find new water sources. No other potamids were observed at the type locality.

Chao Huang, Hsi-Te Shih and Si Ying Mao. 2016. Yuebeipotamon calciatile, A New Genus and New Species of Freshwater Crab from southern China (Crustacea, Decapoda, Brachyura, Potamidae).  ZooKeys. 615: 61-72. DOI:  10.3897/zookeys.615.9964

Crab from the Chinese pet market turns out to be a new species of a new genus  @physorg_com

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