Xie X et al. (2022), Description of two species of the genus Astrod...

ECB-ART-51625

Zookeys 2022 Jan 01;1123:99-122. doi: 10.3897/zookeys.1123.87397.

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Description of two species of the genus Astrodia Verrill, 1899 (Ophiuroidea, Euryalida, Asteronychidae), including a new species from seamounts in the West Pacific.

Xie X , Lu B , Pang J , Zhang D .

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Five specimens of Ophiuroidea from deep-sea seamounts in the West Pacific were collected and identified as two species, Astrodiaduospina sp. nov. and Astrodiaabyssicola. The new species, Astrodiaduospina 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 Astrodiaabyssicola, 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.

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	Figure 1. Sampling sites of two species in the Philippine Sea and the Northwest Pacific (red circles represent the sampling sites of Astrodiaduospina sp. nov., the blue circle represents the sampling site of Astrodiaabyssicola).
	Figure 2. In situ and on-board photos of Astrodiaduospina 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).
	Figure 3. Morphological characters of Astrodiaduospina sp. nov. (holotype: RSIO61068) A aboral view of the disc B periphery of the aboral disc C oral view of the disc D genital silts E aboral view of the arms F arms spines. Abbreviations: RS radial shield; PO plate-shaped ossicle; M madreporite; T teeth; OT oral tentacle; GS genital slit; G gonad; LAP lateral arm plate; AS arm spine. Scale bars: 2 mm (A, C, E); 1 mm (B, D); 0.5 mm (F).
	Figure 4. Vertebrae in basal arm of Astrodiaduospina sp. nov. (holotype: RSIO61068) A proximal view B distal view C oral view D aboral view E, F lateral view. Abbreviations: PB podial basin; LF lateral furrow. Scale bars: 200 μm (A–F).
	Figure 5. Vertebrae in distal arm of Astrodiaduospina sp. nov. (holotype: RSIO61068) A proximal view B distal view C oral view D aboral view E, F lateral view. Abbreviations: PB podial basin; LF lateral furrow. Scale bars: 100 μm (A–F).
	Figure 6. Lateral arm plates and arm spines of Astrodiaduospina sp. nov. (holotype: RSIO61068) A, B lateral arm plates from proximal arm, outer view (A), inner view (B) C, D lateral arm plates from distal arm, outer view (C), inner view (D) E, F arm spines from proximal (E) and distal arm (F). Abbreviations: MO muscle opening; NO nerve opening; R ridge. Scale bars: 200 μm (E); 100 μm (F); 90 μm (A, B); 60 μm (C, D).
	Figure 7. Morphological characters of paratypes of Astrodiaduospina sp. nov. A arm spines of RSIO31004 B arm spines of RSIO61069 C–E pictures of RSIO59012, oral disc (C), aboral disc (D), arm and arm spines (E) F aboral disc of RSIO31004. These specimens have exceptionally three arm spines for an arm segment (shown by an arc in A and B). Abbreviations: AS arm spine; T teeth; PO plate-shaped ossicle; GS genital slit; G gonad; RS radial shield. Scale bars: 2 mm (F); 1 mm (C, E); 0.5 mm (A, B, D).
	Figure 8. In situ and on-board photos of AstrodiaabyssicolaA photo in situ (RSIO68002, attached to an unidentified sea pen species) B, C photos on board (RSIO68002), aboral side (B), oral side (C). Scale bars: 10 mm (B, C).
	Figure 9. Morphological characters of Astrodiaabyssicola (RSIO68002) A aboral view of the disc B center of the aboral disc C oral view of the disc D genital silts E aboral view of the arms F arms spines. Abbreviations: RS radial shield; M madreporite; T teeth; ADS adoral shield; OT oral tentacle; GS genital slit; G gonad; LAP lateral arm plate; AS arm spine. Scale bars: 2 mm (A, C, E); 1 mm (B, D, F).
	Figure 10. Vertebrae in basal arm of Astrodiaabyssicola (RSIO68002) A proximal view B distal view C oral view D aboral view E, F lateral view. Abbreviations: PB podial basin; LF lateral furrow. Scale bars: 150 μm (A–F).
	Figure 11. Vertebrae in distal arm of Astrodiaabyssicola holotype: RSIO68002) A proximal view B distal view C oral view D aboral view E, F lateral view. Abbreviations: PB podial basin; LF lateral furrow. Scale bars: 150 μm (C, D, E); 90 μm (A, B, F).
	Figure 12. Lateral arm plates and arm spines of Astrodiaabyssicola (RSIO68002) A, B lateral arm plates from the proximal arm, outer view (A), and inner view (B) C, D lateral arm plates from the distal arm, outer view (C), and inner view (D) E, F arm spines from proximal (E) and distal (F). Abbreviations: MO muscle opening; NO nerve opening; R ridge. Scale bars: 90 μm (A, B, F); 60 μm (C, D, E).
	Figure 13. Maximum likelihood tree of the genus Astrodia based on concatenated sequences of COI and 16S (clades of Lin 1A, Lin 1B, Lin 2A, Lin 2B, Lin 2C and Lin 3 are from Okanishi et al. (2018), more detailed information about these clades showed in Suppl.materials. Values of each clade: SH-aLRT support (%) / ultrafast bootstrap support (%)).

References [+] :

Hoang, UFBoot2: Improving the Ultrafast Bootstrap Approximation. 2018, Pubmed

﻿Description of two species of the genus Astrodia Verrill, 1899 (Ophiuroidea, Euryalida, Asteronychidae), including a new species from seamounts in the West Pacific.

Description of two species of the genus Astrodia Verrill, 1899 (Ophiuroidea, Euryalida, Asteronychidae), including a new species from seamounts in the West Pacific.