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| Astrodia duospina Xie, Lu, Pang & Zhang, 2022 |
Abstract
Five specimens of Ophiuroidea from deep-sea seamounts in the West Pacific were collected and identified as two species, Astrodia duospina sp. nov. and Astrodia abyssicola. The new species, Astrodia duospina sp. nov., can be distinguished from its congeners by having indistinct or underdeveloped oral papillae, relatively short genital slits, crescent-shaped lateral arm plates, and plate-shaped external ossicles on the aboral surface of the disc. One specimen was identified as Astrodia abyssicola, which has been reported in the north-western Pacific and the north-eastern coast of Japan. The most recent tabular key of Astrodia was revised with two more key characteristics added, the shape and presence of oral papillae and the number of arm spines. The phylogenetic relationship of Astrodia and Asteronyx was analyzed based on 16S and COI sequences. The discovery of the two species further expanded the geographical distribution of the genus Astrodia.
Keywords: Deep sea, molecular phylogeny, morphology, ophiuroids, taxonomy
Systematics
Class Ophiuroidea Gray, 1840
Order Euryalida Lamarck, 1816
Family Asteronychidae Ljungman, 1867
Genus Astrodia Verrill, 1899
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| In situ and on-board photos of Astrodia duospina sp. nov. A photo in situ (RSIO61068: the individual below, RSIO61069: the individual above, attached to an unidentified sea pen species) B photo on board (RSIO61068: the individual on the left, RSIO61069: the individual on the right) C, D photos on board (RSIO31004), aboral side (C), oral side (D). Scale bars: 10 mm (B); 20 mm (C, D). |
Astrodia duospina sp. nov.
Diagnosis: Disc raised high above the arm. Aboral disc with plate-shaped external ossicles in the center and on the periphery. Radial shield narrow, longer than wide. Teeth triangular, oral papillae indistinct or underdeveloped. Genital slits short, approximately one-fourth of the height of the disc. Lateral arm plates crescent and not projecting on arms. Arm spines no more than two.
Etymology: The species name duo is derived from the Latin numeral word, meaning two, and Latin feminine noun, spina, meaning spine, referring to the presence of no more than two arm spines throughout the arm.
Xiaojun Xie, Bo Lu, Jie Pang and Dongsheng Zhang. 2022. Description of Two Species of the Genus Astrodia Verrill, 1899 (Ophiuroidea, Euryalida, Asteronychidae), including A New Species from Seamounts in the West Pacific. ZooKeys. 1123: 99-122. DOI: 10.3897/zookeys.1123.87397
