A new species of Paramunida Baba, 1988 from the Central Pacific Ocean and a new genus to accommodate P. granulata (Henderson, 1885)

Abstract

The genus Paramunida belongs to the most diverse family of galatheoids and it is commonly reported from the continental slope across the Indian and Pacific Oceans. Examination of material collected by the NOAA RV Townsend Cromwell Cruise near Christmas (Kiritimati) Island, Kiribati, revealed the existence of a new species of Paramunida (P. haigae), which represents the fourth record of the genus for the Central Pacific. Furthermore, recent efforts to unravel phylogenetic relationships and diversification patterns in Paramunida revealed P. granulata (Henderson, 1885) to be the most basally diverging taxon within the genus. This species is clearly distinguished from other species of Paramunida by the spinulation of the carapace and the length of the distomesial spine of the second antennal peduncle article, which in combination with a high level of genetic divergence suggest that this species represents a separate monotypic lineage. A new genus, Hendersonida gen. n., is proposed to accommodate this species based on morphological and molecular evidence. An updated dichotomous identification key for all species of Paramunida is presented.

A new species of squat lobster of the genus Hendersonida (Crustacea, Decapoda, Munididae) from Papua New Guinea

“…Two conspicuous diagnostic characteristics differentiate the Hendersonida genus from Paramunida: the granulated surface of the carapace; and the long distomesial spine of antennal article 2, almost reaching the end of the anterior prolongation of article 1 (Cabezas and Macpherson 2014). The morphology of the new species, however, shows that the long distomesial spine of antennal article 2 is not a valid generic character because this spine is moderately short, only reaching the end of antennal article 3, in H. parvirostris.…”

“…Hendersonida is closely related to a clade corresponding to the genus Paramunida Baba, 1988(Cabezas et al 2012Cabezas and Macpherson 2014). The two genera show genetic divergences values higher than expected between species, and within the range observed between other genera of munidid squat lobsters Cabezas and Macpherson 2014). They can also be morphologically differentiated by differences in the spinulation of the carapace and the length of the distomesial spine of the antennal article 2 (Cabezas and Macpherson 2014).…”

“…Indeed, given the general values of nucleotide substitution rate for the COI marker, the age of divergence of these two species of Hendersonida would be placed by the Early Miocene, at the time when most munidids suffered a notably burst of speciation (Cabezas et al 2012). Moreover, the granulated surface of the carapace is constant in both species, and seems to be a diagnostic synapomorphy of the genus, in addition to the shape of the sternum, specifically the anterior margin of the sternite 4 (Cabezas and Macpherson 2014).…”

“…Among these genera, the genus Paramunida Baba, 1988 was proposed based on the presence of spinules or granules densely covering the carapace dorsally (rather than transverse ridges), the short undeveloped rostrum, the antennal peduncle with a well-developed anterior prolongation of article 1, and the absence of the first pair of male gonopods (Baba 1988). Hendersonida Cabezas & Macpherson, 2014 was proposed for one species, Paramunida granulata (Henderson, 1885), widely distributed from the Philippines to Polynesia. Hendersonida is closely related to a clade corresponding to the genus Paramunida Baba, 1988(Cabezas et al 2012Cabezas and Macpherson 2014).…”

“…Hendersonida Cabezas & Macpherson, 2014 was proposed for one species, Paramunida granulata (Henderson, 1885), widely distributed from the Philippines to Polynesia. Hendersonida is closely related to a clade corresponding to the genus Paramunida Baba, 1988(Cabezas et al 2012Cabezas and Macpherson 2014). The two genera show genetic divergences values higher than expected between species, and within the range observed between other genera of munidid squat lobsters Cabezas and Macpherson 2014).…”