Research Article |
Corresponding author: Jinghuai Zhang ( zhangjinghuai@sohu.com ) Academic editor: Christopher Glasby
© 2017 Jinghuai Zhang, Jian-Wen Qiu.
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:
Zhang J, Qiu J-W (2017) A new species of Pectinaria (Annelida, Pectinariidae), with a key to pectinariids from the South China Sea. ZooKeys 683: 139-150. https://doi.org/10.3897/zookeys.683.12272
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Pectinariidae is a family of polychaetes building unique ice-cream cone shaped sandy tubes. Pectinaria torquata sp. n. (Pectinariidae) is described from the coastal waters of the northern South China Sea. This new species can be distinguished from all other 25 recognized species in the genus by a combination of characters: 16 chaetigers; 26–32 cirri in the cephalic veil; 11–12 pairs of cephalic spines; uncini with major teeth arranged in two rows, each with 7–8 major teeth; presence of a dorsal posterior lobe on segments 2 and 20; 4–5 pairs of curved scaphal hooks; and an anal flap with a crenulated margin. A key to all recognized pectinariids in the South China Sea is provided.
invertebrate, Pectinaria , polychaete, South China Sea, taxonomy
Pectinariidae is a family of polychaetes commonly found in the soft bottom of coastal shallow waters. They are easily recognized by their unique ice-cream cone shaped sandy tube, and two bundles of golden thick chaetae called paleae on the first segment which they use for sediment digging (
Pectinaria can be distinguished from other genera of Pectinariidae by a combination of characters: smooth opercular rim; cephalic veil free with numerous cirri; and neurochaetal uncini having major teeth arranged in two or more rows (
Specimens were collected while undertaking a benthic ecology monitoring program of the South China Sea Environmental Monitoring Center (SCSEMC), State Oceanic Administration. Benthic samples were collected from the northern South China Sea using a 0.05 m2 van Veen grab, and rinsed through a sieve with 0.5 mm mesh size. Samples retained on the sieve were collected, fixed in 5% formalin, and later transferred to 70% ethanol. Type specimens are deposited at the Institute of Oceanology, Chinese Academy of Science (IOCAS), Qingdao. Specimens were examined under a Carl Zeiss Stemi 2000-C dissecting microscope. Morphological features were recorded using a Carl Zeiss AxioCam ICc 1 digital camera attached to the microscopes. A paratype was freeze-dried using a Xiangyi CFD-10D, gold coated using an EDT SC-150, and examined under a TESCAN CEGA 3 scanning electron microscope (SEM). Line drawings were made using a Wacom Intuos Pro Pen and Touch Large Tablet.
The taxonomic terms defined by
Pectinaria
Savigny in
Nereis cylindraria belgica Pallas, 1766, designated by
All type specimens are deposited in the Marine Biological Museum (MBM), Institute of Oceanology, Chinese Academy of Sciences, Qingdao
MBM240082: complete specimen, 22°45.17'N, 114°42.98'E (Daya Bay, Guangdong Province), 9.0 m water depth, muddy sand, August 2015.
MBM240083: complete specimen, 22°35.50'N,114°33.22'E (Daya Bay, Guangdong Province), 11.0 m water depth, muddy sand, June 2015. MBM240084: incomplete specimen with 17 anterior segments, 21°39.42'N, 108°34.46'E (Beibu Gulf, Guangxi Province), 9.7 m water depth, muddy sand, August 2015.
The specific epithet torquata is a Latin adjective for collar, which refers to the elevated collar-like dorsal posterior lobe on segment 2, a distinctive feature for this species.
Opercular margin smooth. Cephalic veil free from operculum, with 26–38 cirri along the rim. Segments 2 and 20 with a dorsal posterior lobe respectively. Body with 16 chaetigers. Neurochaetal uncini with major teeth arranged in two rows. Scaphe formed by fusion of five posterior segments. Four or five pairs of scaphal hooks.
Preserved specimen pale cream in color. Body stout with cephalic region enlarged (Figs
Pectinaria torquata sp. n. Holotype MBM240082. A ventral view of the whole worm B lateral view of anterior body C lateral view of the posterior including the scaphe D dorsal view of the posterior including the scaphe E an uncinus F scaphal hooks G anterior view of a notochaeta H posterior view of a notochaeta. Abbreviations: al, anal lobe; an, anus; br, branchia; c3 chaetiger 3; (segment 7) c16, chaetiger 16 (segment 20); cv cephalic veil; op opercular palea; pp peristomial palp; s2 dpl, dorsal posterior lobe on segment 2; s21 segment 21 sc, scaphe; sh, scaphal hooks; tc, tentacular cirrus.
Opercular margin raised with smooth edge (Figs
Segment 1 with pair of tentacular cirri arising from antero–ventral edge near outer most paleae. Segment 2 with pair of tentacular cirri arising from both sides; tentacular cirri connected by flattened ridge running across venter (Figs
Pectinaria torquata sp. n. paratype MBM240084. A lateral view of anterior body B ventral view of anterior body C tentacular cirri II D–F close-up of notochaetae from chaetiger 3 G, a notochaeta from chaetiger 5 H–J close-up of notochaeta from chaetiger 12 K uncini from chaetiger 12 Abbreviations: br, branchia; c4, chaetiger 4 (segment 8); cv, cephalic veil; op, opercular palea; pp, peristomial palp; s2 dpl, dorsal posterior lobe on segment 2; s2 vl, ventral lobe on segment 2; tc, tentacular cirrus.
Chaetigers 1–3 (segments 5–7) uniramous with pair of wedge-shaped notopodia only (Fig.
Notopodia with two kinds of capillaries forming bundle: both with finely hirsute surface on anteromedian margin and smooth surface on posterior margin; one kind with serrations along anterior portion of tip; the other kind smooth, tapering to very acute tip (Figs
Scaphe distinctly separated from segment 21 (Figs
Pectinaria torquata sp. n., holotype MBM240082. A dorsal view of whole specimen B ventral view of whole specimen C tube D dorsal view of posterior end E anal flap F scaphal hooks G lateral view of anterior end H ventral view of posterior end. Paratype MBM240083 I lateral view of posterior end. Abbreviations: al, anal lobe; br, branchia; c4, chaetiger 4 (segment 8); c16, chaetiger 16 (segment 20); cv, cephalic veil; op, opercular palea; pp, peristomial palp; s2 dpl, dorsal posterior lobe on segment 2; s20 dpl, dorsal posterior lobe on segment 20; s21, segment 21; sc, scaphe; sh, scaphal hooks; tc, tentacular cirrus.
Comparison among the types shows that the body width in the cephalic region varies from 8 to 10 mm. The number of paleae varies from 11 to 12 pairs. The number of cirri on the cephalic veil margin varies from 26 to 32. The number of scaphal hooks varies from 4 to 5 pairs. Since there are only two complete and one incomplete specimens of similar sizes, intraspecific variation amongst these morphological characters may have been underestimated.
Currently only known from Daya Bay (Guangdong Province) and Beibu Gulf (Guangxi Province) in the northern South China Sea.
Pectinaria torquata sp. n. can be distinguished from the other 25 described species of Pectinaria by several features (Table
A key to eleven species of Pectinariidae, including P. torquata sp. n., that have been recorded from the South China Sea in the literature is provided below (
Species | Number of cirri on cephalic veil | Number of pairs of paleae | Posterodorsal lobe in segment 2 | Rows of major teeth per uncinus | Middosal anal cirrus of anal flap | Scaphal hooks | Distribution | Literatures cited | |
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Type | Number of pairs | ||||||||
Pectinaria aegyptia (Savigny, 1818) | 60–65 | 15–17 | n.r. | 2 | present | pointed, strongly curved | 4–5, | Red Sea, Japan |
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P. antipoda Schmarda, 1861 | 17–29 | 5–13 | absent | 2–4 | present | blunt, curved or spiral | 6–8 | Australia |
Hutchings 2015 |
P. belgica (Pallas, 1766) | 17–28 | 8–15 | absent | 2–4 | present | pointed | 6–12 | Sweden, Japan |
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P. brevispinis Grube, 1878 | 22–30 | 10–13 | absent | 2 | absent | blunt | 8–14 | Philippines, Indonesia |
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P. californiensis Hartman, 1941 | 18–30 | 13–14 | n.r. | 2 | present | pointed, slight curved | 13 | Southern California |
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P. c. newportensis Hartman, 1941 | 19 | 12–14 | n.r. | 2 | present | pointed, curved | 12–13 | California |
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P. carnosus Wong & Hutchings, 2015 | 16 | 9 | absent | 2 | absent | blunt, slight curved | 6 | Lizard Island |
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P. clava Grube, 1878 | 10–12 | 11 | absent | 3 | n.r. | pointed | 6 | Lapinig Canal, Philippines |
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P. chilensis (Nilsson, 1928) | 30–60 | 8–10 | n.r. | 2 | present | slight curved | 13–15 | Coronel, Chile |
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P. torquata sp. n. | 26–32 | 11–12 | present | 2 | absent | blunt, curved | 4–5 | South China Sea | This study |
P. conchilega Grube, 1878 | 12 | 11 | absent | 3–4 | absent | pointed, curved | 4 | Bohol, Philippines |
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P. dimai Zachs, 1933 | n.r. | n.r. | n.r. | 3–4 | n.r. | n.r. | n.r. | North Japan Sea |
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P. dodeka Hutchings & Peart, 2002 | 16–28 | 11–13 | absent | 2–4 | present | pointed, stongly curved | 6–10 | Queensland, Australia |
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P. gouldii (Verrill, 1874) | 12–38 | 9–15 | n.r. | 2–4 | present | Lanciform, pointed, strait or slight curved | 8–22 | Long Island Sound |
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P. hartmanae Reish, 1968 | 30 | 8–10 | n.r. | 2 | present | blunt | 8–10 | California, USA |
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P. hiuchiensis Kitamori, 1965 | 32–35 | 9–10 | absent | 2 | absent | pointed, slight curved | 8–9 | Kyushu, Japan |
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P. kanabinos Hutchings & Peart, 2002 | 10–16 | 12–14 | absent | 2–4 | present | pointed, stongly curved | 4–6 | Queensland, Australia |
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P. longispinis Grube, 1878 | 17 | 13 | absent | n.r. | n.r. | n.r. | 4 | Philippines |
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P. meredithi Long, 1973 | 16–21 | 8–11 | n.r. | 2–3 | present | pointed, strait or slight curved |
7–9 | Bahamas and Florida Keys |
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P. nana Wesenberg-Lund, 1949 | 8 | 11 | absent | n.r. | present | n.r. | 3 | Gulf of Oman Iran |
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P. okudai (Imajima & Hartman, 1964) | 10–15 | 13–16 | absent | 3–4 | present | pointed, slight curved | 12–13 | Japan |
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P. panava Willey, 1905 | 32 | 10 | n.r. | n.r. | n.r. | n.r. | 7 | Sri Lanka |
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P. papillosa Caullery, 1944 | 24–46 | 11–13 | absent | 2 | absent | n.r. | 3–11 | Indonesia |
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P. parvibranchis Grube, 1878 | 12–13 | 10–11 | absent | 3–4 | n.r. | pointed | 4 | Pangloo, Philippines |
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P. profunda Caullery, 1944 | 20 | 12 | n.r. | 2 | present | n.r. | n.r. | Indonesia |
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P. regalis (Verrill, 1901) | 21–35 | 8–14 | absent | 2–3 | present | pointed, strait | 0–4 | Cony Island, Bermuda |
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1 | Opercular rim smooth | 5 |
– | Opercular rim cirrate | Amphictene (2) |
2 | Less than 15 pairs of scaphal hooks | 3 |
– | More than 15 pairs of scaphal hooks | 4 |
3 | 5–8 pairs of scaphal hooks; opercular rim with cirri | Amphictene capensis (Pallas, 1776) |
– | 12 pairs of scaphal hooks; opercular rim with denticles | Amphictene leioscapha (Caullery, 1944) |
4 | 19–24 pairs of scaphal hooks; without pair of dorsolateral lobes on segment 3 | Amphictene japonica Nilsson, 1928 |
– | 26–37 pairs of scaphal hooks; with pair of dorsolateral lobes on segment 3 | Amphictene alata Zhang, Zhang & Qiu, 2015 |
5 | Cephalic veil laterally attached | Lagis (6) |
– | Cephalic veil free | Pectinaria (8) |
6 | Branchiae absent | Lagis crenulatus Sun & Qiu, 2012 |
– | Branchiae present | 7 |
7 | Margins of anal lobe with long fringes | Lagis bocki (Hessle, 1917) |
– | Margins of anal lobe without fringes | Lagis koreni Malmgren, 1866 |
8 | Segment 2 with a posterodorsal lobe | Pectinaria torquata sp. n. |
– | Segment 2 without a posterodorsal lobe | 9 |
9 | 6–8 pairs of scaphal hooks; anal flap with a small cirrus | Pectinaria antipoda Schmarda, 1861 |
– | 3–4 pairs of scaphal hooks; anal flap without anal cirrus | 10 |
10 | Cephalic veil with 24–46 cirri; major teeth of uncini in 2 rows | Pectinaria papillosa Caullery, 1944 |
– | Cephalic veil with 12 cirri; major teeth of uncini in 3–4 rows | Pectinaria conchilega Grube, 1867 |
This study was supported by the National Natural Science Foundation of China (Grant no. 41406179 to J.H. Zhang) and Guangdong Natural Science Foundation (Grant no. 2014A030310495 to P. Wu). The authors are grateful to Xiaojun Shi, Xiangli Lv, Yang Gao for their help in sample collection, Shaoqing Wang for his assistance in depositing specimens, and Pat Hutchings, Chris Glasby and an anonymous reviewer for their helpful comments and suggestions for the improvement of this paper.