A new subfamily classification of the highly diversified Dorippidae H. Milne Edwards, 1837 (Crustacea, Decapoda, Brachyura, Dorippoidea), using morphological, molecular and palaeotonlogical data, with special emphasis on its unique female reproductive system

Abstract

A new and revised classification of the small family Dorippidae H. Milne Edwards, 1837, which previously comprised two distinct subfamilies (Dorippinae H. Milne Edwards, 1837 and Ethusinae Guinot, 1977), each of which was subsequently elevated to a familial rank supported by traditional data and genetic phylogenies, is presented on the basis of a morphological analysis involving a large number of characters. The family is in fact highly diverse, at all levels. Several features are described and depicted in detail here for the first time, e.g. the presence of a diversely developed strip along the protrudingly rimmed posterior margin of the carapace; on the dorsally exposed thoracic sternite 8, a process acting as an additional pleonal-retention mechanism in the females of three genera (Dorippe Weber, 1795; Philippidorippe Chen, 1986; Phyllodorippe Manning & Holthuis, 1981); a callosity at the base of the coxa of the third pereiopod, variously shaped, in two genera (Dorippe and Dorippoides Serène & Romimohtarto, 1969). The generic and specific taxonomy masterfully stabilised by Holthuis & Manning (1991) is undisputed and still valid, except for the composition of the genus Heikeopsis Ng, Guinot & Davie, 2008 that may well contain in northern China a form not entirely consistent with the typical Heikeopsis japonica (von Siebold, 1824) of Japan. A second exception concerns the genus Paradorippe Serène & Romimohtarto, 1969 sensu Holthuis & Manning (1991) that may not be monophyletic. The validity of Medorippe crosnieri Chen, 1988, questioned by Holthuis & Manning (1990), could not be confirmed here: its distinctive morphological characters from M. lanata (Linnaeus, 1767) suggest that it could be recognised one day. The synthesis of conventional and new characters allows the traditional taxonomic approach to be updated and modernised, more complete and robust diagnoses to be constructed, and groups of genera to be circumscribed. We propose a new subfamily classification whereby the family Dorippidae is recognised as monophyletic but with seven genera assigned to subfamily-level rank, leading to the recognition of seven distinct subfamilies: the Dorippinae H. Milne Edwards, 1837 n. stat. (Dorippe), Dorippoidinae n. subfam. (Dorippoides), Medorippinae n. subfam. (Medorippe Manning & Holthuis, 1981), Heikeopsinae n. subfam. (Heikeopsis, Neodorippe Serène & Romimohtarto, 1969, Nobilum Serène & Romimohtarto, 1969), Paradorippinae n. subfam. (Paradorippe), Philippidorippinae n. subfam. (Philippidorippe) and Phyllodorippinae n. subfam. (Phyllodorippe). There is a high degree of concordance between several elements of our proposal: 1) the main morphological patterns of the male gonopods lead to the recognition of seven subfamilies; 2) the main morphological patterns of the vulvae correspond to the seven observed gonopod types and lead to the recognition of the same seven subfamilies; 3) the recognition of several subfamilies is supported by the well-defined clades obtained by the molecular analyses; and 4) the female re...