Himalayapotamon Pretzmann, 1966

Valarmathi, Kandasamy, 2017, Himalayapotamon chambaensis, a new species of freshwater crab (Crustacea: Brachyura: Potamidae) from Himachal Pradesh, India, Zootaxa 4324 (3), pp. 482-490 : 488-489

Key to the species of Himalayapotamon Pretzmann, 1966

1. Adults relatively large, carapace width exceeds 3 cm in adult; carapace relatively more transverse...................... 2

- Adults relatively small, carapace width generally not exceeding 3 cm; carapace relatively squarish.................... 7

2. G1 terminal segment relatively long, slender, strongly bent outwards............................................. 3

- G1 terminal segment relatively stout, short and straight or slightly bent outwards................................... 4

3. G1 terminal segment elongated, relatively longer, ca. 0.4 times of combined length of subterminal segment and flexible zone, conical, strongly bent outwards, sometimes up to 70-80° in mature male, G2 distal segment very long, strongly coiled, tip upturned............................................................................ H. chambaensis n. sp.

- G1 terminal segment long, broadly triangular, ca. 0.3 times combined length of subterminal segment and flexible zone, G2 dis- tal segments bent hook like..................................................... H. marinelli (Pretzmann, 1963)

4. G1 terminal segment short, conical, bent outwards, tapering towards tip, G2 terminal segment bent hook like...................................................................................... H. garhwalense Pati & Singh, 2017

- G1 terminal segment straight or slightly bent outwards, G2 almost straight........................................ 5

5. Between the post orbital cristae and epi-branchial corner, there is a short additional crest, tip of the G1 terminal segment blunt, triangular, inner distal part of subterminal segment convex, flexible zone V- shaped........ H. emphyseteum (Alcock, 1909)

- Post orbital cristae continuous to epibranchial tooth, though cervical groove cut it in the middle, tip of G1 terminal part S- shaped, due to the slight long dorsal part cross over the relatively shorter ventral part............................... 6

6. G1 terminal segment with straight outer margin, flexible zone bilobed........... H. sunkoshiense Brandis & Sharma, 2005

- G1 terminal segment with outer margin convex, flexible zone asymmetrical........ H. atkinsonianum ( Wood-Mason, 1871)

7. Cervical groove deep along entire length; G1 terminal segment broadly triangular, tip truncate, directed downwards....................................................................................... H. bifarium (Alcock, 1909)

- Cervical groove often becoming shallower distally; G1 terminal segment tip not truncate or directed downwards.......... 8

8. Terminal segment of G1 almost conical, lateral sides of distal end of subterminal segment straight, without angular projection; G2 distal segment straight or bent towards median part of sternopleonal cavity............... H. monticola ( Alcock, 1910)

- Terminal segment of G1 almost broadly triangular, distal end of subterminal segment with angular distal lateral projection.. 9

9. Branchial region of carapace and cheliped surface prominently rough due to presence of numerous thin sharp serrated striae................................................................................ H. ambivium (Alcock, 1909)

- Branchial region of carapace and cheliped surface rugose, covered with some striae and granules but relatively less sharp....................................................................................................... 10

10. G1 terminal segment with a tuft of stiff setae medially................................ H. kasaulis (Pretzmann, 1966)

- G1 terminal segment with scattered stiff setae (not as a tuft).................................................. 11

11. Tip of G1 terminal segment elongate, long, conical................................... H. koolooense ( Rathbun, 1904)

- Tip of G1 terminal segment short, conical............................................ H. babaulti ( Bouvier, 1918)