Chrysogorgia dendritica Xu, Zhan & Xu, 2020

Xu, Yu, Zhan, Zifeng & Xu, Kuidong, 2020, Morphology and phylogenetic analysis of five deep-sea golden gorgonians (Cnidaria, Octocorallia, Chrysogorgiidae) in the Western Pacific Ocean, with the description of a new species, ZooKeys 989, pp. 1-37: 1

publication ID

http://dx.doi.org/10.3897/zookeys.989.53104

publication LSID

lsid:zoobank.org:pub:8957A11D-0098-4990-B073-A1999A8AFBC6

persistent identifier

http://treatment.plazi.org/id/105222F6-271F-5F64-8AD5-C6EAA58B8402

treatment provided by

ZooKeys by Pensoft

scientific name

Chrysogorgia dendritica Xu, Zhan & Xu, 2020
status

 

Chrysogorgia dendritica Xu, Zhan & Xu, 2020   Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 ; Table 1

Chrysogorgia dendritica   Xu, Zhan & Xu, 2020: 6-8, figs 2, 3.

Type locality.

Kocebu Guyot in the Magellan Seamount chain, 1821 m depth.

Voucher specimens. MBM286353, station FX-Dive 71 (11°20.83'N, 139°15.87'E), a seamount (tentatively named as M2) near the Mariana Trench, depth 1375 m, 28 March 2016. MBM286442, station FX-Dive 211 (10°02.97'N, 140°10.48'E), a seamount (tentatively named as M5) located on the Caroline Ridge, depth 1475 m, 29 May 2019. MBM286443, station FX-Dive 211 (10°03.27'N, 140°10.70'E), a seamount (M5) located on the Caroline Ridge, depth 1387 m, 29 May 2019. MBM286444, station FX-Dive 227 (10°37.92'N, 140°05.62'E), a seamount (tentatively named as M8) located on the Caroline Ridge, depth 1702 m, 15 June 2019. GenBank accession number: MT269888.

Extended diagnosis.

Chrysogorgia   "group A, Spiculosae" with 1/3L Branching sequence and a monopodial or a little zigzagging stem. Juvenile with a bottlebrush-like colony, while adult usually having a tree-shaped colony. Branches nearly perpendicular to stem, subdivided dichotomously. Polyps with a long neck and an expanded base. Rods and rare scales in tentacles, longitudinally arranged. Rods/spindles and elongate scales in polyp neck longitudinally arranged, coarse with many warts on surface. Scales and rare plates at the basal polyp body irregularly and alternately arranged, irregular and often amoeba-shaped. Scales in coenenchyme sparse and elongate, usually lobed with irregular edges.

Description.

For morphological measurements, see Table 1 View Table 1 .

Distribution.

Kocebu Guyot, 1821 m ( Xu et al. 2020); a seamount adjacent to the Mariana Trench and seamounts on the Caroline Ridge, 1375-1702 m depth.

Remarks.

The four specimens match the holotype of Chrysogorgia dendritica   Xu, Zhan & Xu, 2020 in having a monopodial stem and the same sclerite form, for example, rods and rare scales in tentacles, rods/spindles and elongate scales in polyp neck, irregular scales at the basal polyp body, and elongate scales in coenenchyme. Moreover, their mtMutS gene sequences are identical (see the genetic analysis below). Thus, we identified the four specimens as C. dendritica   . The sclerites in the four voucher specimens and the holotype showed some differences: (1) rod-like scales with an obvious medial contraction often present in MBM286353 and MBM286442, while rare in the holotype, MBM286443 and MBM286444 (Figures 1A View Figure 1 , 2H View Figure 2 vs. Figures 3D View Figure 3 , 4D View Figure 4 ); (2) large cured spindles are rarely present in the polyp neck of the holotype, MBM286443 and MBM286444, while absent in the other two specimens (Figures 3F View Figure 3 , 4F View Figure 4 vs. Figures 1F View Figure 1 , 2I View Figure 2 ); (3) scales at the basal polyp body of the holotype and MBM286444 are more irregular and amoeba-shaped than the other specimens (Figure 4E View Figure 4 vs. Figures 1H View Figure 1 , 2K View Figure 2 , 3E View Figure 3 ); and (4) scales in coenenchyme are more elongate in MBM286442 than the other specimens (Figure 2J View Figure 2 vs. Figures 1G View Figure 1 , 3G View Figure 3 , 4G View Figure 4 ). However, these differences are minor and not constant, and we thus treate as the conspecific variation.

The four specimens of C. dendritica   showed a series of growth stages, from bottlebrush-like colony (juvenile) to tree-shaped colony (adult). Considering the diameter size of the stem base and scars on the stem, the specimen MBM286442 is likely a juvenile with a narrow stem and without scars, while the other specimens have wider stems and some old scars of the past branches (Table 1 View Table 1 ). The juvenile has a bottlebrush-like colony (Figure 2B View Figure 2 ), while the adult has a long monopodial stem with branches occurring on the top, forming a tree-shaped colony (Figures 1B View Figure 1 , 3B View Figure 3 ). Compared to the changing colony shapes, the sclerite forms showed small variation in the growth stages and can be used as a main character to identify the species.

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

Order

Alcyonacea

Family

Chrysogorgiidae

Genus

Chrysogorgia

Loc

Chrysogorgia dendritica Xu, Zhan & Xu, 2020

Xu, Yu, Zhan, Zifeng & Xu, Kuidong 2020
2020
Loc

Chrysogorgia dendritica

Xu, Zhan & Xu 2020
2020