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| Clavelina ossipandae Hasegawa & Kajihara, 2024 |
Abstract
An unidentified colonial ascidian called gaikotsu-panda-hoya in Japanese, literally meaning ‘skeleton panda ascidian,’ has been attracting SCUBA divers’ attention for the past few years since its strange appearance was introduced on the Internet by a diving shop in Kumejima Island, Japan. To confirm the taxonomic status of this species, fresh samples were collected from a diving point off the coast of Kumejima Island. Our morphological examination revealed that they represent a new species, herein described as Clavelina ossipandae sp. nov., which can be distinguished from 44 congeners in the genus Clavelina Savigny, 1816 by the combination of the following seven characteristics: i) colony consisting of completely free zooids, ii) zooids up to 20 mm in length, iii) in the living state, zooids transparent, with laterally elongated white patch between oral and atrial siphons, as well as four black markings, one between siphons, one mid-dorsally, and the other two situated laterally in a pair on the anterior part of the body, iv) transverse vessels white, v) endostyle black, vi) 10–14 stigmatal rows, and vii) two longitudinal muscular bands running from the abdomen to the endostyle on each side. Partial sequences (810 bp) of the cytochrome c oxidase subunit I gene from the holotype and one of the paratypes differed at 10 sites from each other (1.26% K2P distance) but were the same when translated into amino acids. A phylogenetic tree supported that this species is included in the genus Clavelina.
Keywords: Aplousobranchia, Chordata, Clavelinidae, East China Sea, Enterogona, Okinawa Islands, subtropical, taxonomy
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| Clavelina ossipandae sp. nov., holotype, ICHUM 5837. A, In situ live colony with four zooids; B, a schematic depiction of the colony showing colony organization and zooid insertion; C, D, a single zooid detached from the colony, drawn from the right side (C) and the left side (D). |
Clavelina ossipandae sp. nov.
Diagnosis. A Clavelina with colony consisting of zooids extending from basal mass; zooids completely free, mean 15mm long; in life, a white, laterally elongated white patch present between oral and atrial siphons; small black point present on anterior body wall between oral and atrial siphons; an elongated black band situated laterally to the small black point on each side, slightly curved along edge of the white patch; transverse vessels white; endostyle black; short mid-dorsal black line situated posterior to atrial siphon, spanning for about four transverse vessels; 10–14 stigmatal rows in pharynx; on each side of thorax, 10 or 11 very thin longitudinal muscle bands, of which two running to endostyle, 5–6 to branchial siphon, and 2–4 to dorsal side.
Etymology. The new specific name, ossipandae, is a noun in the genitive case, a composite derived from os (‘bone’ in Latin) and ‘Panda,’ the latter is meant to be the giant panda, Ailuropoda melanoleuca David, 1869, and herein treated as a noun that is latinized. The species is so named because the white anterior portion of the zooid with the characteristic black markings resembles to the face of the giant panda and the white transverse vessels evoke the ribs of a skeleton.
Naohiro Hasegawa and Hiroshi Kajihara. 2024. Graveyards of Giant Pandas at the Bottom of the Sea? A strange-looking New Species of Colonial Ascidians in the Genus Clavelina (Tunicata: Ascidiacea). Species Diversity. 29(1); 53-64. DOI: 10.12782/specdiv.29.53
