A new species of the genus Petrolisthes Stimpson (Crustacea, Decapoda, Porcellanidae) from the Central Pacific, with remarks and new records for P. aegyptiacus Werding & Hiller.

Alexandra Hiller,Bernd Werding

doi:10.3897/zookeys.617.9893

Abstract

Petrolisthes paulayi sp. n. is described from specimens collected in French Polynesia. The new species belongs to an assemblage of morphologically similar Indo-West Pacific (IWP) species, here designated as the “mesobranchial-spine group”. All species in the group bear carapace spines, including one or more mesobranchial spines, and transverse, piliferous striations on the dorsal surface of carapace and chelipeds. Petrolisthes paulayi sp. n. is distinguishable from all species in the group by its forwardly produced, trilobate front, and a characteristic combination of carapace spines. We also report on the range extension and live coloration of Petrolisthes aegyptiacus Werding & Hiller, another species of the mesobranchial-spine group, so far considered a Red Sea endemic. Specimens from the Mascaréne Islands confirm that the geographic range of the species extends to the southern Indian Ocean. While specimens morphologically similar to Petrolisthes aegyptiacus, and collected in the Line and Society Islands, suggest a large range extension to the Central Pacific, it is probable that these individuals represent an undescribed species closely related to Petrolisthes aegyptiacus.

Highlights

The genus Petrolisthes Stimpson, 1858, is the most species-rich genus of the family Porcellanidae (Crustacea, Decapoda, Anomura, Galatheoidea), with 109 species worldwide (Dong et al 2010; Hiller and Werding 2010; Osawa and McLaughlin 2010; Osawa and Maenosono 2011; Osawa and Uyeno 2013; Naderloo and Apel 2014; Werding and Hiller 2015)
Inner margin armed with a small supraorbital spine, followed mostly by a second tubercle-like elevation that is sometimes armed with a spine; infraorbital angles forming an acute edge
Petrolisthes paulayi sp. n. was first found in the Line Islands, and subsequently in the Society Islands

Summary

Introduction

The genus Petrolisthes Stimpson, 1858, is the most species-rich genus of the family Porcellanidae (Crustacea, Decapoda, Anomura, Galatheoidea), with 109 species worldwide (Dong et al 2010; Hiller and Werding 2010; Osawa and McLaughlin 2010; Osawa and Maenosono 2011; Osawa and Uyeno 2013; Naderloo and Apel 2014; Werding and Hiller 2015). Kropp (1984) upgraded this group with newly described species. The two groups are taxonomically difficult because they contain numerous complexes of species with high intraspecific variation in diagnostic characters that sometimes overlap interspecifically. Some of these complexes have been disentangled by examining large series of specimens from different localities Kropp 1984; Werding and Hiller 2015; Osawa and Ng 2016), and by comparing DNA sequences from different conspecific and sympatric morphotypes suspected to represent different species (Hiller et al 2006; Hiller and Werding 2007, 2010) Some of these complexes have been disentangled by examining large series of specimens from different localities (e.g. Kropp 1984; Werding and Hiller 2015; Osawa and Ng 2016), and by comparing DNA sequences from different conspecific and sympatric morphotypes suspected to represent different species (Hiller et al 2006; Hiller and Werding 2007, 2010)

Methods

Results

Conclusion