Table 1 Characters useful for distinguishing the shrimps Athanas dimorphus Ortmann, 1894 and A. nitescens (Leach, 1813 [in Leach 1813–1814])
Species characters | Athanas dimorphus | Athanas nitescens |
|---|---|---|
Chelae pattern | Carried folded | Carried extended |
Merus of male chela | Inflated, laterally flattened, and wider than palm; ventral portion strongly excavated to accommodate chelae when folded | Short and narrow, slightly flattened laterally, and slightly excavated on distal ventral margin |
Carpus of male chela | Very short, corresponding to only 0.25 times palm length | Cup-shaped, slightly less than half palm length; distal portion as wide as palm |
Palm of male chela | Distinctly narrower and more inflated in middle and distal portions; wider in middle portion | Inflated, subcylindrical in proximal portion, and laterally compressed in distal portion; dorsal and ventral margins almost parallel |
Fingers of male chela | Distinctly less than 1/2 palm length | Roughly 1/2 length of palm |
Supra-corneal tooth | Absent | Present, with rounded tip |
Infra-corneal tooth | Rounded tip; fails to reach apex of extra-corneal tooth | Acute tip; almost reaches tip of extra-corneal tooth |
Basicerite | No rounded lobe; acute infero-lateral tooth present | With a rounded lobe and an acute infero-lateral tooth |
Merus of male P2 | Broad (approximately 4 times as long as broad) | Narrow (approximately 9 times as long as broad) |
Antepenultimate segment of endopodite of maxilliped 3 | Broad | Narrow |