Notoixys planiceps Kim & Boxshall 2020, gen. et sp. nov.

• Main Authors: Kim, Il-Hoi, Boxshall, Geoff A.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2020
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Ascidiacea; Enterogona; Didemnidae; Notoixys; Notoixys planiceps; Antarc*; Antarctic; Antarctic Peninsula
• Online Access: https://doi.org/10.5281/zenodo.5699921; http://treatment.plazi.org/id/03C487CBED56383FFCEFFF63FEFFFA34

Notoixys planiceps gen. et sp. nov. (Figs. 346, 347) Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21392), paratypes (3 intact ♀♀, MNHN-IU-2014-21393), and dissected paratypes (2 ♀♀, figured) from Aplidium cyaneum Monniot C. & Monniot F., 1983 (MNHN-IT-2008-295 = MNHNA 1/ APL.B/129), Cruise Eltanin 32, Stn 2127, Antarctic Peninsula (71°23’S, 171°36’E), depth 515-521 m, SOSC coll., 13 February 1968. Etymology . The specific name of the new species is derived from the combination of the Latin plan (=flat) and ceps (=head), alluding to the flattened cephalosome. Descriptionoffemale . Body (Fig. 346A) robust, 1.37 mmlong. Prosome 1.14 mmlong: dorsalcephalic shield dorsoventrally flattened (Fig. 346A), expanded ventrally, tapering anteriorly in dorsal view towards angularanterior apex, andwithpairedhorn-likeprocesses posterolaterally (Fig. 346B). Metasome swollen, unsegmented, 1.7 times longer than dorsoventral depth, with arched dorsal margin and straight ventral margin. Freeurosome (Fig. 346C) small, recurved ventrally, tapering posteriorly, distinctly 5-segmented: genital and 4 abdominalsomites 55×230, 64×175, 60×141, 44×116, and 56×96 μm, respectively. Anal somite and caudal rami covered with setules; anal somite with deep posteromedian incision. Caudalramus (Fig. 346D) about 2.9 times longer than wide (82×28 μm) and shorter than anal somite: armedwith 6 setae (outer lateral, dorsal, and 4 distal); outer distal and dorsal setae positioned at 48 and 60% of ramus length, respectively; all caudal setae small, less than half width of ramus. Rostrum (Fig. 346E) large, elongate, densely covered with setules, proximal half with parallel margins, distal half tapering. Antennule (Fig. 346F) 7-segmented, but terminal segment bearing traces of 2 articulations; first and second segments much broader than other segments; setal armature not discernible due to similarity with setules. Antenna (Fig. 346G) 4-segmented; proximal 3 segments unarmed; terminal segment (second endopodal segment) 3.1 timeslongerthan wide (62×20 ...