Biodiversity Data Journal :
Taxonomy & Inventories
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Corresponding author: Yejie Lin (linyejie15@gmail.com)
Academic editor: Panakkool Thamban Aneesh
Received: 16 Dec 2022 | Accepted: 13 Feb 2023 | Published: 20 Feb 2023
© 2023 Qianhui Zeng, Yejie Lin
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:
Zeng Q, Lin Y (2023) New records of parasitic copepod (Crustacea, Siphonostomatoida, Pennellidae) found on the body surface of two cetacean species in China. Biodiversity Data Journal 11: e98914. https://doi.org/10.3897/BDJ.11.e98914
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Pennella balaenoptera Koren & Danielssen, 1877 (Crustacea, Siphonostomatoida, Pennellidae) is so far known as the largest copepod species and has only been found as a parasite on marine mammals. Previous studies on parasitic copepods in China only focused on those found on economic fishes, no records of P. balaenoptera having ever been reported before.
A Bryde's whale (Balaenoptera edeni Anderson, 1879) and a pygmy sperm whale [Kogia breviceps (Blainville, 1838)] were respectively stranded on the eastern and southern coast of China in 2021 and 2022. A total of eight parasitic copepods found on their body surface were sampled and examined. The parasites were identified as Pennella balaenoptera, based on morphological characteristics and measurements. Descriptions and photomicrographs of this newly-recorded species from China are given in the present study.
new distribution, taxonomy, cetacean external parasites, Pennella
Species of the genus Pennella Oken, 1815 (Crustacea, Siphonostomatoida, Pennellidae) are medium-sized parasitic arthropods that predominantly parasitise on the surface of marine fishes and marine mammals (
Cetaceans are large-sized, fast-moving and wide-ranging animals that live in the water throughout their lives; thus, their external parasite samples are not easily collected in the wild. Most cetacean external parasites were collected from their stranded carcasses, including parasitic copepods (e.g.
On 27 July 2021, a 6.85 m long baleen whale was found stranded on a mudflat in Rui'an, Wenzhou (Fig.
On 21 May 2022, a 2.52 m long toothed whale was found stranded on a sandy beach in Xichong, Shenzhen (Fig.
The specimens were all preserved in 75% ethanol. They were later soaked in trypsin solution for 12 hours to dissolve and wash off the residual host cetacean tissues on their body surface. The processed specimens were examined under a LEICA M205C body view microscope. Images were captured with an Olympus C7070 zoom digital camera (7.1 megapixels) and superimposed by Helicon Focus 6.7.1 and then processed in Adobe Photoshop CC 2018. All measurements are in millimetres (mm) and were obtained with an Olympus SZX16 stereomicroscope with a Zongyuan CCD industrial camera.
The specimens are currently deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing (IZCAS). The terminology used in the text and figures follows
Based on morphological features, the specimens are identified as Pennella balaenoptera. Since male P. balaenoptera is free-living like other non-parasitic copepods, while the female is parasitic, the samples obtained in this study are all females.
These parasites were rooted in the host bodies by elongated anchor-like structures, which passed through the blubber and the skin (Fig.
One specimen (IZCAS-Ar43746) (Fig.
"Head": 3.64 long, 4.12 wide; Holdfast horns: left 11.32 long, 2.02 wide; right 15.23 long, 1.62 wide; dorsal 11.53 long, 1.51 wide; "Neck": 43.61 long, 1.47 wide; Trunk: 40.53 long, 3.64 wide; Abdomen: 29.64 long.
Colouration. Specimens cephalothorax yellow; neck, trunk and abdomen dark brown in ethanol. Divided into three regions: cephalothorax, carapace and abdomen. Ovisacs missing.
Cephalothorax. Divided into cephalic and thoracic regions, separated by a constricted region between the two parts. Cephalic region spherical, slightly wider than long, abdominal side to the front mask mastoid, with dense, different sized spherical mastoid branches (Fig.
Thoracic region. The neck, the longest part of this region extremely elongated with a wider trunk and accounts for 72% of the body, transversely striated, the orifices of the oviducts appear at the posterior end of the trunk, crescent-shaped (Fig.
Abdomen. Cylindrical, with lateral, feather-like processes. Each of these feather-like processes has a different shape (Fig.
Ovisacs missing.
Hosts: Balaenoptera edeni, 6.85 m long; Kogia breviceps, 2.52 m long.
The species Pennella balaenoptera was first described by
As a sexually dimorphic species, female P. Balaenoptera is large and half-buried in the host's body, appearing as a hanging tag or filament (
Table 1: Cetacean hosts and microhabitats in some Pennella balaenopterae infestation cases.
Host |
Host family |
Microhabitat |
Location |
Reference |
Balaenoptera acutorostrata (Common minke whale) |
Balaenopteridae |
All but head region |
Around Iceland |
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B. bonaerensis (Antarctic minke whale) |
Balaenopteridae |
Flanks |
Southern Ocean |
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B. physalus (Fin whale) |
Balaenopteridae |
Flanks (Sampled regions); Abdomen |
North-eastern Mediterranean coast of Turkey; Mediterranean Sea |
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B. edeni (Bryde's whale) |
Balaenopteridae |
Dorsal region, flanks and ventral side |
Eastern coast of China |
Present study |
Grampus griseus (Risso's dolphin) |
Delphinidae |
Head region (melon) and behind the mammary gland |
North-eastern Mediterranean coast of Italy |
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Stenella coeruleoalba (Striped dolphin) |
Delphinidae |
Flanks |
Mediterranean coast of Spain |
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Phocoena phocoena (Harbour porpoise) |
Phocoenidae |
Flanks and caudal peduncle |
Aegean coast of Turkey |
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Kogia breviceps (Pygmy sperm whale) |
Kogiidae |
Head |
Eastern Pacific coast of USA |
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K. breviceps (Pygmy sperm whale) |
Kogiidae |
Dorsal region (near the dorsal fin) |
Southern coast of China |
Present study |
Severe infestations caused by P. balaenoptera are often found on weakened hosts (
Compared to records of P. balaenoptera found on the rorquals (family Balaenopteridae), records found on the family Kogiidae are scarce. It was firstly reported attached to a pygmy sperm whale (Kogia breviceps) in 1951 (
Previous studies on P. balaenoptera morphology, life history and parasitism effects were mainly concentrated in the Mediterranean district (Table
The manuscript benefitted greatly from comments by Panakkool Thamban Aneesh, Helna Ameri Kottarathil and two anonymous reviewers. We sincerely thank Dr. Songhai Li and Dr. Peijun Zhang from the Institute of Deep-sea Science and Engineering, Chinese Academy of Science, for providing us with an opportunity to collect the parasite specimens when conducting dissection of the Balaenoptera edeni. We also give special thanks to Baolin Liao and his team member Xiaozhou Yang from the Shenzhen Institute of Guangdong Ocean University for helping us collect the parasite specimens from the Kogia breviceps.