Biodiversity Data Journal :
Taxonomic Paper
|
Corresponding author: Jun-Hui Lin (linjunhui@tio.org.cn), Jian-Jun Wang (wangjianjun220@tio.org.cn)
Academic editor: Sarah Faulwetter
Received: 16 Oct 2020 | Accepted: 16 Nov 2020 | Published: 19 Nov 2020
© 2020 Jun-Hui Lin, María García-Garza, He-Shan Lin, Jian-Jun Wang
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lin J-H, García-Garza ME, Lin H-S, Wang J-J (2020) A new species of Leiochrides Augener, 1914 (Annelida: Capitellidae) from the Beibu Gulf, South China Sea. Biodiversity Data Journal 8: e59726. https://doi.org/10.3897/BDJ.8.e59726
|
|
Polychaetes of the family Capitellidae are poorly studied in Chinese waters. Amongst the known capitellid genera in China, Leiochrides Augener, 1914 is an unusual genus encountered in marine surveys.
In this study, a Leiochrides specimen was obtained during a survey conducted in the Beibu Gulf, northern South China Sea and described herein as a new species Leiochrides guangxiensis sp. nov. The new species differs from its congeners by having uniramous chaetiger 1, chaetigers 11–12 with notopodial capillaries and neuropodial hooks, abdominal hooks with seven teeth above the main fang in three rows, pygidium with four anal cirri, and branchial fascicles with up to 17 filaments. The taxonomic status of the monospecific genus Pseudoleiocapitella Harmelin, 1964 and Leiochrides norvegicus Fauchald, 1972 are discussed.
Polychaeta, Capitellidae, Leiochrides, South China Sea, taxonomy
Polychaetes in the family Capitellidae resemble terrestrial earthworms (
In China, capitellid polychaetes are frequently encountered in marine surveys. However, they are poorly understood, as most recorded species lack taxonomic descriptions and illustrations. Based on personal collections from southern China, more than 10 genera are recognized within this family, including Barantolla, Capitella, Heteromastus, Leiocapitella, Leiochrides, Mediomastus, Notodasus, Notomastus, Parheteromastus, and Promastobranchus. Of these, the genus Leiochrides is rarely collected, as well as Leiocapitella and Parheteromastus. Leiochrides specimens have been previously collected from Chinese waters, and they were usually identified as Leiochrides australis (
The Leiochrides specimen was obtained from the Beibu Gulf, northern South China Sea in October, 2017. The sediment was characterized by high percentage of mud. Sediment samples were collected with a grab sampler (surface area 0.05 m2) and washed through a 0.5 mm sieve on board. All specimens retained by the sieve were fixed with 7% diluted formalin in seawater. In the lab, the Leiochrides specimen was transferred to 70% ethanol. The methyl green staining pattern (MGSP) was used to identify the distribution of glandular areas, following the protocol of
The type material of the new species was deposited in the Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China.
Holotype (TIO-BTS-Poly-111) complete, but broken into four fragments. Anterior fragment (Fig.
Holotype of Leiochrides guangxiensis sp. nov. A. thorax and anterior abdomen (23 chaetigers) in dorsal view, arrow indicates the separation of thorax and abdomen; B. thorax and anterior abdomen (17 chaetigers) in ventral view; C. anterior end in lateral view; D. chaetigers 9–19, showing transition between thorax and abdomen in lateral view; E. middle abdomen in lateral view; F. posterior abdomen in dorsal view; G. pygidium; H. hooded hook from middle abdomen; I. dentition of abdominal hooks. Shading on A–B indicates methyl green staining. Scale Bar: A–G = 1 mm; H = 10 μm; I = 2 μm
Leiochrides guangxiensis sp. nov. holotype. A. thorax and anterior abdomen in lateral view, showing methyl green staining; B. anterior end in dorsal view; C. anterior end in lateral view; D. chaetigers 11–20 in dorsal view; E. chaetigers 7–17 in lateral view; F. chaetigers 8–20 in ventral view; G. posterior abdomen; H–J. notopodial branchiae; K. posterior end showing branchiae and anal cirri; L. abdominal hooks; M. SEM photos of abdominal hooks. Abbreviations: ac, anal cirrus; br, branchiae; cc, capillary chaetae; ch, chaetiger; hh, hooded hook; lg, lateral groove; lo, lateral organ; neu, neuropodia; no, notopodia; per, peristomium; pro, prostomium; prob, proboscis; pyg, pygidium; vg, ventral groove. Scale Bar: A–J = 1 mm; K = 0.5 mm; L = 10 μm; I = 2 μm
Thorax with an achaetous peristomium and 12 chaetigers (Fig.
Transition between thorax and abdomen indistinct, marked by change in chaetal arrangement (Fig.
Notopodial and neuropodial abdominal hooks similar along body, with long anterior shaft, developed shoulder, angled node, distinct constriction, and short hood (Fig.
Notopodial branchiae present in posterior abdomen, located on posterior edge of segment, may be retractile (Fig.
Methyl green staining: Dark blue stain from post-chaetal part of chaetiger 7 to chaetiger 10 (Fig.
The specific name is derived from the type locality, Guangxi Province.
Currently known from the Beibu Gulf, northern South China Sea.
The new species inhabits shallow subtidal waters where sediment is characterized by high percentage of mud.
The taxonomic and ecological knowledge of this genus is very rare in China, although Leiochrides species have been previously recorded (
The dentition of abdominal hooks is widely used in capitellid taxonomy, as their ultrastructure is highly specific (
In this study, the taxonomic status of the genus Pseudoleiocapitella Harmelin, 1964 and Leiochrides norvegicus Fauchald, 1972 was found to be doubtful when reviewing the literature on capitellid species related to Leiochrides. The monospecific genus Pseudoleiocapitella was established by
We are very grateful to the members of the Marine Benthos Laboratory (TIO, MNR) for their assistance in collecting and photographing capitellid specimens. We thank Dr. Xikun Song from Xiamen University for his assistance in using the scanning electron microscope. We also thank Drs Sarah Faulwetter, Wagner Magalhães, and Camila da Silva for their suggestions to improve the manuscript. This study was financially supported by the Public Science and Technology Research Funds Projects of Ocean under contract No. 201505004.