A review of the <i>Chaenostoma boscii</i> species-complex (Decapoda: Brachyura: Macrophthalmidae) from the Indo-West Pacific

Abstract

Abstract. The sentinel crabs, Chaenostoma orientale Stimpson, 1858, and C. crassimanus Stimpson, 1858, were both described from the Ryukyu Islands, Japan, and have both been long considered junior synonyms of C. boscii (Audouin, 1826). After examining specimens of the C. boscii species-complex from East Africa, the Malay Peninsula, Indonesia, New Caledonia, Papua New Guinea, the Philippines, Taiwan, and the Ryukyus, we now consider both C. crassimanus and C. orientale to be valid species, and C. lisae (Poupin & Bouchard, 2010) is found to be a synonym of C. crassimanus, based on the morphology of the carapace, male cheliped and male first gonopod, supported by molecular evidence from mitochondrial cytochrome oxidase subunit I (COI) sequences. Both C. orientale and C. crassimanus are found sympatrically in Taiwan (including Penghu), and possibly in the Ryukyus and New Caledonia. While C. boscii is endemic to the Red Sea, the distribution of C. sinuspersici is limited to the western Indian Ocean (East Africa and the Persian Gulf).

On the distribution range of Chaenostoma sinuspersici (Naderloo & Türkay, 2011) (Decapoda: Brachyura: Macrophthalmidae) in Indian waters

“…The morphology of the specimens (Fig. 1) examined herein matches the description and illustrations given by Naderloo and Türkay (2011) and Teng et al (2016), but varied slightly in following characters: lateral margins of third somite of male abdomen are strongly curved (Fig. 1d) (vs. almost straight in holotype of C. sinupersici), operculum of female gonopore (Fig.1e) is larger in size reaching median part of gonopore opening (vs. smaller operculum not reaching median part of gonopore opening in paratype female of C. sinupersici).…”

“…Another species, Chaenostoma lisae (Poupin & Bouchard, 2010) is now considered as junior synonym of C. crassimanus (Shih et al, 2015;Teng et al, 2016). Chaenostoma sinuspersici was described from Persian Gulf and has a widespread distribution in Indo-West Pacifi c (Naderloo and Türkay, 2011;Teng et al, 2016). In the present study, C. sinuspersici is reported fi rst time from Indian waters.…”

“…Chaenostoma currently contains six species: Chaenostoma boscii (Audouin, 1826), Chaenostoma punctulatus (Miers, 1884), Chaenostoma sinuspersici (Naderloo & Türkay, 2011), Chaenostoma java Naderloo, 2013, Chaenostoma orientale Stimpson, 1858 and Chaenostoma crassimanus Stimpson, 1858(Stimpson, 1858Ng et al 2008;Naderloo and Türkay, 2011;Naderloo, 2013;Shih et al, 2015, Teng et al, 2016. Another species, Chaenostoma lisae (Poupin & Bouchard, 2010) is now considered as junior synonym of C. crassimanus (Shih et al, 2015;Teng et al, 2016). Chaenostoma sinuspersici was described from Persian Gulf and has a widespread distribution in Indo-West Pacifi c (Naderloo and Türkay, 2011;Teng et al, 2016).…”

“…1d) (vs. almost straight in holotype of C. sinupersici), operculum of female gonopore (Fig.1e) is larger in size reaching median part of gonopore opening (vs. smaller operculum not reaching median part of gonopore opening in paratype female of C. sinupersici). Teng et al (2016) recently reviewed C. boscii species complex and identified six valid species using the following morphological characters: direction of first anterolateral tooth; depth and shape of incision present between first and second anterolateral tooth; shape of dactylar tooth of chela; presence and extent of setal patch on inner margin of cheliped palm; and shape of G1. Chaenostoma sinupersici shows similarity with C. boscii and C. orientale in having slender chela but varies from these two species in the following characters: The first and second anterolateral teeth are of same extent in C. sinuspersici (Fig.…”

Development of a new set of PCR primers for eDNA metabarcoding decapod crustaceans

“…Türkay 2011, Teng et al 2016) and M. boscii and allied taxa were transferred to the genus Chaenostoma. Teng et al (2016) showed that two species, C. crassimanus Stimpson, 1858 and C. orientale occur in the north-western Pacific, including Japan, with true C. boscii restricted to the western Indian Ocean. At the studied site, specimens of C. orientale have been collected and, thus, it is reasonable to consider that it was the eDNA of C. orientale that was detected and that the GenBank sequence identified as "Macrophthalmus" boscii has been misidentified.…”