Systematic revision of the Antarctic gastropod family Newnesiidae (Heterobranchia: Cephalaspidea) with the description of a new genus and a new abyssal species

作者：Moles Juan^*; Avila Conxita; Malaquias Manuel A. E.

来源：Zoological Journal of the Linnean Society, 2018, 183(4): 763-775.

DOI：10.1093/zoolinnean/zlx089

• Adelie Land
• biodiversity
• deep sea
• Drake Passage
• Hocius gen. nov.
• Newnesia
• Southern Ocean
• taxonomy
• Weddell Sea

Antarctica has been hypothesized as a centre of origin of major heterobranch gastropod radiations, like Cephalaspidea and Nudipleura. Yet the study of Antarctic heterobranch diversity has been largely hampered by a lack of detailed morphological and anatomical studies, as well as comparative molecular phylogenetic approaches. Recently, the new cephalaspidean Newnesiidae was proposed to include two Antarctic endemic species. In this study, we review the diversity and relationships of the family using an expanded taxon sampling with broader geographical coverage, including the Atlantic and Pacific sides of Antarctica. An integrative taxonomic approach combining both morphological and molecular phylogenetics is used here. The diet of these molluscs is studied by gut content using scanning electron microscopy. A new species from abyssal depths is described, namely Newnesia abyssalis sp. nov., and the new genus Hocius gen. nov. is erected to reflect the phylogeny and the unique traits of the species Hocius joani comb. nov. The type species N antarctica is redescribed based on specimens from off Adelie Land close to the type locality (Ross Sea). The diet results were not entirely conclusive but suggest diatoms to be the predominant food source. This would support the hypothesis that herbivory is the plesiomorphic feeding condition in Cephalaspidea.

• 出版日期2018-8