Zoological Studies

Vol. 59, 2020

(update: 2020.08.01; 09.22)

Somniosus (Rhinoscymnus) cheni sp. nov., A New Species of Sleeper Shark (Squaliformes: Somniosidae) from Eastern Taiwan, with Aspects of Embryo Biology

Hua-Hsun Hsu1, Chia-Yen Lin2,3, and Shoou-Jeng Joung2,3,*


1Marine Studies Section, Center for Environment and Water, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. E-mail: hsuhuahsun@yahoo.com.tw (Hsu)
2Department of Environmental Biology and Fisheries Science, National Taiwan Ocean University, Keelung 20224, Taiwan. E-mail: skinomotohiko@gmail.com (Lin)
3George Chen Shark Research Center, National Taiwan Ocean University, Keelung 20224, Taiwan. *Correspondence: E-mail: f0010@ntou.edu.tw (Joung). Tel: +886-2-24622192 ext. 5039

(Received 3 June 2019 / Accepted 28 July 2020)
Communicated by Hin-Kiu Mok

A new species of sleeper shark is described based on a 134.0 cm total length pregnant female collected from off Hualien, eastern Taiwan. The species belongs to a small species group (subgenus Rhinoscymnus) and can be distinguished from its congeners in having a smaller second dorsal fin, smaller eyes, more rows of teeth in the upper jaw and fewer in the lower jaw, and a different body proportion. Moreover, the specimen had 33 embryos, which is substantially more than the two other small species in the subgenus.Information on embryo biology are also provided.

Key words: Elasmobranch, Litter size, Morphology, Sex-bias, Taxonomy.

Citation: Hsu HH, Lin CY, Joung SJ. 2020. Somniosus (Rhinoscymnus) cheni sp. nov., a new species of sleeper shark (Squaliformes: Somniosidae) from eastern Taiwan, with aspects of embryo biology. Zool Stud 59:48. doi:10.6620/ZS.2020.59-48.