Journal article

Publication year: 2010

Pages: 117-124

Journal: Zoosystematics and Evolution

Volume number: 86

Issue number: 1

DOI Link: https://doi.org/10.1002/zoos.200900016

Publisher: Pensoft Publishers

Abstract: 

In the Pacific, most angel sharks display rather limited geographic
distributions. Recent findings of three specimens of the Taiwan angel
shark, Squatina formosa, from Tosa Bay, Kochi Prefecture, Japan
enlarges the known geographic range of this species considerably. So
far, this species only has been known from Taiwan. Other records might
be considered misidentifications. The three specimens that form the
focus of this study are from the central Tosa Bay (Province of Kochi) in
SE Japan. They were collected with otter trawls in ca. 200 m depth in
May and June 2008. Although these specimens differ slightly from the
holotype from Taiwan in some features, their identification as belonging
to Squatina formosa is well supported by the colour pattern and a
suite of morphological characters such as shape and meristics of the
upper lip arch, the shape of the caudal fin lobe and the shape and size
of the pectoral, pelvic and dorsal fins. Additionally, the taxonomic
identification is strongly supported by molecular and data by comparison
with a specimen from Taiwan and previously published data. The mtDNA
difference between the Taiwanese and Japanese populations is 0.2 % and
is most likely related to a descent from a postulated original
population some 10,000 years ago. It is most likely that this species
occurs from the small Batan Islands, along the Ryukyu Trench and the
corresponding Ryukyu Islands from Taiwan north along the south‐eastern
mainland coast of Japan. This species seemingly occurs along the
Kuroshio Current and is absent from cold‐influenced waters (e.g. western
Taiwan, China and Japan seas). The recent finding of this species in
Tosa Bay most probably is due to range extension because of globally
increasing sea water temperatures.

Harvard Citation style: Kriwet, J., Endo, H. and Stelbrink, B. (2010) On the occurrence of the Taiwan angel shark, Squatina formosa Shen & Ting, 1972 (Chondrichthyes, Squatinidae) from Japan, Zoosystematics and Evolution, 86(1), pp. 117-124. https://doi.org/10.1002/zoos.200900016

APA Citation style: Kriwet, J., Endo, H., & Stelbrink, B. (2010). On the occurrence of the Taiwan angel shark, Squatina formosa Shen & Ting, 1972 (Chondrichthyes, Squatinidae) from Japan. Zoosystematics and Evolution. 86(1), 117-124. https://doi.org/10.1002/zoos.200900016