Marphysa Quatrefages, 1865

Liu, Yubin, Hutchings, Pat & Kupriyanova, Elena, 2018, Two new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicida: Eunicidae) from northern coast of China and redescription for Marphysa orientalis Treadwell, 1936, Zootaxa 4377 (2), pp. 191-215 : 193-194

Genus Marphysa Quatrefages, 1865 , restricted

Diagnosis. (after Molina-Acevedo & Carrera-Parra, 2017).

Prostomium slightly bilobed or completely bilobed; five prostomial appendages without articulations; eyes present or absent. Peristomium without peristomial cirri. Maxillary apparatus with four pairs of maxillae and an unpaired on left side; MI with falcal arch developed, extended, and with the outer edge of the base arched; MIII curved, forming part of distal arc, with attachment lamella of rectangular or irregular shape, situated at the centre of posterior edge of maxilla; MIV with circular or rectangular attachment lamella. Branchiae distributed throughout the body. Dorsal cirri without articulation; postchaetal lobe well developed in anterior region, ventral cirri with swollen base, oval or circular. Aciculae dark or translucent. Supracicular chaetae include limbate; pectinate isodont chaetae with slender teeth, and pectinate anodont chaetae with long teeth present or absent. Subacicular chaetae include compound falcigers or spinigers or both. Subacicular hook, dark or translucent, bidentate or unidentate. Pygidium with two pairs of anal cirri, without articulation.

Remarks. Marphysa is a heterogeneous genus due to the vast variation of morphological features and its definition has been controversial. Zanol et al. (2014) proposed a phylogenetic hypothesis of Eunicidae based on an analysis of morphological and molecular characters, and established two new genera which included species previously assigned to Marphysa . They suggest that characters previously used to delineate genera within the family, such as the number of prostomial appendages and the presence or absence of peristomial cirri are not informative. However, until a complete revision of the genus Marphysa is undertaken, we are following the above definition of Molina-Acevedo & Carrera-Parra (2017), who acknowledge that the genus is not monophyletic.

Fauchald (1970) reviewed the 48 species of Marphysa accepted at the time and arranged them into five artificial groups (referred to as groups A–E) based on the type of compound chaeta present, since then an additional 18 species have been described. According to the grouping, group A includes species lacking compound chaetae, species in B have compound spinigers only, species in C have compound falcigers only, those in D have both compound falcigers and spinigers, and E unites species too poorly known with the respect of their compound chaetae to be categorised. Fauchald (1970) further subdivides species in groups A–E into those with branchiae restricted to a short anterior region only (1) and those with branchiae present throughout most of the body length (2). This classification was followed by Glasby & Hutchings (2010) and Zanol et al. (2016). Some support for these morphological groups was obtained during a molecular study of the Eunicidae family by Zanol et al. (2014), but they sequenced only 12 species of Marphysa and found two basal groups in Marphysa s. str. which represent a “ Marphysa sanguinea -like” group B and a “ Marphysa belli -like”-group D. Zanol et al. (2014) provided an emended generic diagnosis, however Molina-Acevedo & Carrera-Parra (2017) added some further characters with regards to the maxillary apparatus and parapodial structures which we used here. We have followed Molina- Acevedo & Carrera-Parra (2015) and Zanol et al. (2016) for terminology of the pectinate chaetae.