A new species of Parasesarma (Decapoda: Brachyura: Sesarmidae) from northern Australian mangroves and its distinction from morphologically similar species

A new species of mangrove crab, Parasesarma austrawati, is described from northern Australian mangroves. The new species is genetically distinct from all congeners, based on three mitochondrial (Cox1, ND1, 16S), and one nuclear (NaK) DNA markers. Morphologically, the new species is most similar to Parasesarma samawati, Parasesarma longicristatum and Parasesarma semperi with 7 or 8 rounded, well developed chelar dactylus tubercles, and appears to have been previously misidentified as P. longicristatum with which it occurs sympatrically. It differs, however, from P. longicristatum and P. semperi by having relatively shorter cheliped fingers as well as more distinct dorsal carapace regions and frontal lobes. Genetically, P. austrawati n. sp. is sister to a clade containing Parasesarma lividum from the southwest Pacific and P. samawati from East Africa. P. austrawati n. sp. is the seventh species of Parasesarma reported from northern Australian mangroves west of Torres Strait. (c) 2019 Elsevier GmbH. All rights reserved.