Taxonomic reassessment ofParasesarma(Crustacea: Brachyura: Decapoda: Sesarmidae) based on genetic and morphological comparisons, with the description of a new genus

Abstract

Parasesarma is a species-rich genus whose representatives are common in wetlands and mangroves of the Indo-Pacific. Morphologically, the genus is heterogeneous and has been postulated to constitute a polyphyletic taxon. In the present study, most species of Parasesarma are re-evaluated phylogenetically, using mitochondrial and nuclear molecular markers. The results show that the majority of the examined species cluster consistently with the type species Parasesarma plicatum. However, some species, among them the tree-climbing Parasesarma leptosoma, are clearly separated from this main clade of Parasesarma, forming a second stable monophyletic group, distinct from other known genera. Based on these results, and with additional support by morphological diagnoses highlighting consistent differences between the two species groups, we propose a new genus for the species clustering around P. leptosoma, proposing the new name Leptarma gen. nov.

Molecular phylogeography reveals multiple Pleistocene divergence events in estuarine crabs from the tropical West Pacific

“…Previous phylogenetic analyses on species of Parasesarma [ 36 , 49 , 57 , 81 ] revealed that members of the P . bidens species complex from the Western Pacific ( P .…”

“…guttatum . Under a larger clade, these six species form two reciprocally monophyletic groups, a western clade versus an eastern one [ 36 , 49 , 57 , 81 ]. This pattern highlights the importance of the Indo-Pacific barrier [ 31 ] in structuring phylogeny of these marine invertebrates.…”

“…bidens group [ 36 , 49 , 57 ], in order to re-examine their phylogenetic relationship. Based on previous phylogenetic analyses [ 36 , 57 ], sequences of three other species of the genus, P . eumolpe (De Man, 1895), P .…”

“…With currently 54 extant species, Parasesarma De Man, 1895 is one of the two largest sesarmid genera [ 35 ]. Its representatives are distributed throughout the IWP, mostly in East and Southeast Asia [ 36 ]. In a recent phylogenetic analysis, we recovered several stable clades among species of Parasesarma [ 36 ].…”

“…Its representatives are distributed throughout the IWP, mostly in East and Southeast Asia [ 36 ]. In a recent phylogenetic analysis, we recovered several stable clades among species of Parasesarma [ 36 ]. One of these clades showed similar patterns as those reported for the N .…”