Parachrysogorgia Xu & Zhan & Xu 2023, gen. nov.
Creators: name: Xu, Yu
name: Zhan, Zifeng
name: Xu, Kuidong
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Chrysogorgiidae
Parachrysogorgia

description: Genus Parachrysogorgia gen. nov.
urn:lsid:zoobank.org:act: CCE87C37-7B4D-4670-86A0-5DB963FD0F8D
Diagnosis. Colony branching sympodial, arising from a single ascending spiral (counterclockwise, bottlebrush-shaped colony), two or more fans emerging from a short main stem (bi- or multi-flabellate colony). Axis with a metallic shine. Branch subdivided dichotomously or with branchlets forming a sympodium. Polyps relatively large and stout, with a bare, sclerite-free area at the base of each tentacle and eight distinct projections (acuminate or warty) beneath tentacles. Sclerites in the form of scales in polyp body wall, spindles/rods, and/or scales in tentacles.
Type species. Parachrysogorgia chryseis (Bayer & Stefani, 1988) comb. nov. (basionym: Chrysogorgia chryseis Bayer & Stefani, 1988).
Distribution. Currently known only from the Pacific and North Atlantic Oceans, 329–1937 m.
Species assigned. Thirteen species of Chrysogorgia are transferred to Parachrysogorgia. These are P. admete (Bayer & Stefani, 1988) comb. nov., P. antarctica (Cairns, 2002) comb. nov., P. binata (Xu, Li, Zhan & Xu, 2019) comb. nov., P. bracteata (Bayer & Stefani, 1988) comb. nov., P. calypso (Bayer & Stefani, 1988) comb. nov., P. chryseis (Bayer & Stefani, 1988) comb. nov., P. electra (Bayer & Stefani, 1988) comb. nov., P. expansa (Wright & Studer, 1889) comb. nov., P. octagonos (Versluys, 1902) comb. nov., P. scintillans (Bayer & Stefani, 1988) comb. nov., P. squamata (Verrill, 1883) comb. nov., P. stellata (Nutting, 1908) comb. nov., and P. versluysi (Kinoshita, 1913) comb. nov. Other species (e.g., C. intermedia Versluys, 1902, C. curvata Versluys, 1902) with incomplete descriptions need to be confirmed based on detail morphological examination as well as phylogenetic analyses.
Remarks. Untiedt et al. (2021) recognized nine distinct morphological groups of Chrysogorgia s.l. and hypothesized that each likely represents a distinct genus by using a concatenated UCE and exon loci dataset (Table 4). Our previous phylogenetic analysis based on mtMutS gene data showed that all the available species of Chrysogorgia were clustered into two Clades (I and II), and the genetic distances between Clades I and II (the main Chrysogorgia clade) were much higher than the intra-clade ones of Clade II (Xu et al. 2020a). The newly constructed mtMutS - COI gene and 28S rDNA trees further support the separation of the usual Chrysogorgia species from the new genus Parachrysogorgia (Figs. 1, 2). Parachrysogorgia is morphologically separated from Chrysogorgia by possessing a bare, sclerite-free area present at the base of each tentacle and eight distinct acuminate or warty projections beneath the tentacles. The two features can be easily observed under a bright microscope and are distinct under a scanning electronic microscope (SEM). Both the morphological and molecular data justify the establishment of the new genus.
Parachrysogorgia shares similar external morphology with certain species of Chrysogorgia in having a bottlebrush-shaped colony with a counterclockwise spiral, or bi- or multi-flabellate colony, while Chrysogorgia also contains species with a clockwise spiral, or a planar or tree-shaped colony.
Etymology. Composition of the Greek prefix para (similar to) and the generic name Chrysogorgia, referring to the similarity of the new genus with Chrysogorgia. Feminine gender.
description: Published as part of Xu, Yu, Zhan, Zifeng & Xu, Kuidong, 2023, Studies on western Pacific gorgonians (Anthozoa: Octocorallia, Chrysogorgiidae). Part 1: a review of the genus Chrysogorgia, with description of a new genus and three new species, pp. 1-107 in Zootaxa 5321 (1) on page 20, DOI: 10.11646/zootaxa.5321.1.1, http://zenodo.org/record/8203414