Challenging deep-sea cosmopolitanism: taxonomic re-evaluation and biogeography of ‘<em>Cythere dasyderma</em> Brady, 1880’ (Ostracoda)

2016-06-21T11:12:26Z (GMT) by Simone N. Brandão Moriaki Yasuhara
<p><em>Cythere dasyderma</em> Brady, 1880 was described from samples collected from all the world’s oceans during the HMS <em>Challenger</em> expedition in the 1870s. Subsequently, <em>Cythere dasyderma</em> (or <em>Echinocythereis dasyderma</em>, or <em>Henryhowella dasyderma</em>) has been recorded from the Late Eocene to Recent, from Atlantic, Arctic, Indian, Pacific and Southern oceans, and from intertidal to deep abyssal environments. However, even cursory inspection of illustrations from over 50 publications shows that several species have been included in ‘<em>Cythere dasyderma</em>’. Here, all syntypes of <em>Cythere dasyderma</em> Brady, 1880 archived in the Natural History Museum, London have been re-studied. This species is re-described, re-diagnosed and illustrated with scanning electron microscope images. <em>Cythere dasyderma</em> is assigned to <em>Ayressoleberis</em> gen. nov., which is described here. The geographical distribution of <em>Ayressoleberis dasyderma</em> (Brady, 1880) comb. nov. is no longer cosmopolitan, and includes only the type locality in the abyssal southeastern Pacific. Most of the specimens previously identified as <em>Cythere dasyderma</em>, or its synonyms, belong to other trachyleberidid genera (e.g. <em>Henryhowella</em>, <em>Legitimocythere</em>, <em>Pennyella</em>) and not to <em>Ayressoleberis dasyderma</em> comb. nov. A new species of <em>Ayressoleberis</em>, very similar to <em>Ayressoleberis dasyderma</em> comb. nov., is described and illustrated from specimens previously included amongst the syntypes of ‘<em>Cythere acanthoderma</em> Brady, 1880’. These latter specimens were collected from the continental slope of the southwestern Indian Ocean. This new species is left in open nomenclature herein because only two left valves are currently available. </p>