Thursday, January 3, 2019

[Crustacea • 2018] Indochinamon khinpyae • A New Species of Freshwater Crab (Brachyura, Potamidae) from northern Myanmar

 Indochinamon khinpyae  
Ng & Mar, 2018

A new species of freshwater crab of the genus Indochinamon Yeo & Ng, 2007 (family Potamidae), is described from highlands north of Myitkyina in Kachin State, Myanmar. Indochinamon khinpyae sp. n. is distinguished from congeners by its very rugose carapace, broad male pleon and distinctively structured male first gonopod; and is the first potamid species recorded from northern Myanmar.

Keywords: Taxonomy, freshwater crab, Burma, Potaminae, Indochinamon, new species, description

Figure 1.  Indochinamon khinpyae sp. n., colour in life, holotype male (57.1×43.2 mm) (ZRC 2018.0713).
A dorsal view B ventral view of cephalothorax.

 Figure 2.  Indochinamon khinpyae sp. n. A, D, F holotype male (57.1×43.2 mm) (ZRC 2018.0713) B, E paratype male (47.2×36.4 mm) (ZRC 2018.0714) C, G paratype male (34.3×26.6 mm) (ZRC 2018.0714). A–C overall habitus D, E frontal view of cephalothorax F, G dorsal view of carapace.

Family Potamidae Ortmann, 1896 sensu Yeo and Ng (2004)
Genus Indochinamon Yeo & Ng, 2007

Type species: Potamon villosum Yeo & Ng, 1998, 
by original designation.

Indochinamon khinpyae sp. n.

Diagnosis: Carapace with dorsal surface prominently rugose in large specimens (ca. 45 mm carapace width), frontal and orbital regions prominently rugose, lateral parts of anterolateral and branchial regions with strong oblique striae; mesogastric, urogastric, cardiac and intestinal regions with distinct rugosities and distinct granules (Fig. 2A, D, F); postorbital cristae distinct, margin uneven, outer edge relatively low, not well marked (Fig. 2A, D, F); external orbital tooth distinct, separated from anterolateral margin by deep V-shaped cleft; epibranchial tooth prominent (Fig. 2A, F); anterolateral margin lined with sharp granules, appears serrated (Fig. 2A, F); posterior margin of epistome with distinct median triangle (Fig. 2D); outer surface of chela strongly rugose, upper part rugose with granules (Fig. 3H, I); male thoracic sternum, notably sternites 3 and 4, relatively broad, surface with pits and scattered short, stiff setae (Fig. 3A); male pleon triangular; telson triangular, lateral margins gently sinuous; somite 6 transversely rectangular, much wider than long, lateral margin gently convex (Fig. 3A, B); G1 relatively stout; outer margin of subterminal segment with distinct broad cleft on distal part, terminal segment subcylindrical, gently curving outwards, no visible dorsal flap, distal part tapering to rounded tip (Fig. 4A–D).

Etymology: The species is named after Ms Khin Pyae Pyae Thaw Thar who collected the specimens used for this study. Her name is used here as a noun in apposition.

Colour: In life, the dorsal surfaces of the carapace and outer surfaces of the chelipeds are dark brown; with the ventral surfaces orangish-red; and the ambulatory legs are dark brown to orangish red (Fig. 1).

Habitat: The type locality, Malikha, is a fast-flowing river, the substrate consisting of rocks of various sizes, with the bank sandy. The banks are densely lined with tall trees. This river is a branch of the Ayeyarwady River (= Ayrwarwady River or Myitsone) and is about 43 km north of Myitkyina, the capital city of Kachin State.

 Peter K. L. Ng and Win Mar. 2018. On A New Species of Freshwater Crab, Indochinamon khinpyae, from northern Myanmar (Crustacea, Brachyura, Potamidae). ZooKeys. 811: 47-63. DOI:  10.3897/zookeys.811.29187