Indochinamon bhumibol ( Naiyanetr, 2001 )

Rogers, D. Christopher, Sanoamuang, Laorsri & Sanoamuang, Niwat, 2021, A new semiterrestrial freshwater crab in the genus Badistemon and a new record of Indochinamon from northern Thailand (Brachyura: Potamidae), Raffles Bulletin of Zoology 69, pp. 548-554 : 553

Indochinamon bhumibol ( Naiyanetr, 2001)

Pu Chao Pho Luang, Giant Mountain Crab ( Figs. 2A–E , 3 )

Material examined. THAILAND: Nan Province, Chiang Klang District, Ban Nam Meed Stream , 19°20′3″N, 100°50′3″E, ~ 400 m asl; 4 males, 1 female; August 2018; N. Sanoamuang .

Remarks. Five specimens (one female, four males) of Indochinamon bhumibol were collected at the same site as B. nanensis , new species, described above. As with B. nanensis , new species, I. bhumibol is nocturnal and burrows under large stones along the stream banks. The local people capture them for food using chicken meat.

The largest specimen was a male with a carapace length of 51.6 mm and carapace width of 68.4 mm. Our material fits within the size range presented in the original description, and the form of gonopods I and II ( Fig. 1D, E ), maxilliped III ( Fig. 1B ), as well as the habitat and colouration in life ( Fig. 2A, B ) match the original description very well ( Naiyanetr, 2001).

However, some minor differences are evident. In our material, the carapace dorsolateral rugosities appear to be slightly larger, the orbital and epibranchial teeth slightly more prominent, and the orbital tooth bears a weak marginal bead ( Figs. 1A , 2B, D ). The telson lateral margins are more convex in two of the four males ( Fig. 1C ).

This new record represents a significant range extension. Our locality is approximately 350 km north of the type locality in Loei province ( Naiyanetr, 2001), and is situated in a different drainage system .

Figures

Fig. 2. A–E, Indochinamon bhumibol, male, carapace length 51.6 mm. A, carapace anterior and lateral surfaces, dorsal view; B, maxilliped III; C, male distal pleonal somites, ventral view; D, gonopod I, ventral view; E, male gonopod II. F–I, Badistemon nanensis, new species, holotype male, ZRC 2021.0454.F, maxilliped III; G, male distal pleonal somites, ventral view; H, gonopod I, ventral view; I, male gonopod II.

Fig. 3. Indochinamon bhumibol, male carapace length 51.6 mm. A, colour in life, anterior view; B, preserved, anterior view; C, colour in life, dorsal view; D, preserved, dorsal view.

Fig. 1. Badistemon nanensis, new species, holotype male, ZRC 2021.0454. A, colour in life, anterior view; B, colour in life, dorsal view; C, preserved, anterior view; D, preserved, dorsal view; E, thoracic sternites.