Tubuca alcocki, a new pseudocryptic species of fiddler crab from the Indian Ocean, sister to the southeastern African T. urvillei (H. Milne Edwards, 1852) (Crustacea, Decapoda, Brachyura, Ocypodidae).

Hsi-Te Shih,Peter K L Ng,Benny K K Chan

doi:10.3897/zookeys.747.23468

Abstract

A new pseudocryptic species of fiddler crab, Tubuca alcocki sp. n., is described from the northern Indian Ocean. The new species was previously identified with T. urvillei (H. Milne Edwards, 1852), but can be distinguished by the structures of the anterolateral angle of the carapace and male first gonopod. The molecular data of the mitochondrial cytochrome oxidase subunit I gene shows that both are sister taxa and the divergence time is estimated at 2.2 million years ago, around the beginning of the Pleistocene. While the new species is widely distributed in the northern part of Indian Ocean, occurring from the Red Sea to India and the Andaman Sea; T. urvillei sensu stricto has a more restricted range, and is known only from southeastern Africa.

Highlights

Various genetic and morphological studies on fiddler crabs (Ocypodidae) from the Indian Ocean have shown that there are a number of species endemic to the region: Austruca albimana (Kossmann, 1877), A. bengali (Crane, 1975), A. iranica (Pretzmann, 1971), A. occidentalis (Naderloo, Schubart & Shih, 2016), A. sindensis (Alcock, 1900), Cranuca inversa (Hoffmann, 1874), Paraleptuca chlorophthalmus
The genetics suggest that the cladogenesis of these taxa have their origins in the Indian Ocean
According to Shih et al (2016), T. urvillei is sister to the clade composed of T. dussumieri

Summary

Introduction

Various genetic and morphological studies on fiddler crabs (Ocypodidae) from the Indian Ocean have shown that there are a number of species endemic to the region: Austruca albimana (Kossmann, 1877), A. bengali (Crane, 1975), A. iranica (Pretzmann, 1971), A. occidentalis (Naderloo, Schubart & Shih, 2016), A. sindensis (Alcock, 1900), Cranuca inversa (Hoffmann, 1874), Paraleptuca chlorophthalmus The genetics suggest that the cladogenesis of these taxa have their origins in the Indian Ocean. Of these taxa, Tubuca urvillei is a large-sized species, which has been widely reported from throughout the Indian Ocean and is the only Tubuca Bott, 1973 species known in the western Indian Ocean (Crane 1975; Shih et al 2016). The material from the northern and eastern parts of the Indian Ocean is described as a new pseudocryptic species, T. alcocki

Materials and methods

LC053375