Zoological Studies

Vol. 61, 2022

(update: 2022.11.25)

A New Species of the Bengal Spined Anchovy Stolephorus from the Eastern Indian Ocean and Redescription of Stolephorus dubiosus Wongratana, 1983, with Comments on the Evolution of Prepelvic Scute Numbers within Stolephorus (Clupeiformes: Engraulidae)

Harutaka Hata1,*, Sébastien Lavoué2, and Hiroyuki Motomura3

1National Museum of Natural History, Smithsonian Institution, 10th and Constitution Ave, NW Washington, DC 20560, USA. *Correspondence: E-mail: k2795502@kadai.jp (Hata)
2School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia. E-mail: microceb@hotmail.com (Lavoué)

3The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan. E-mail: motomura@kaum.kagoshima-u.ac.jp (Motomura)

Received 19 January 2022 / Accepted 25 July 2022
Communicated by Hin-Kiu Mok

The Bengal Spined Anchovy, Stolephorus taurus sp. nov. is described from 21 specimens from the northern Bay of Bengal. The new species closely resembles Stolephorus dubiosus Wongratana, 1983, which is redescribed. Both species have a predorsal scute, spine on the pelvic scute, long maxilla posteriorly slightly short of or just reaching the posterior margin of the opercle, 25 or more gill rakers on the lower limb of the first gill arch, and double black lines on the dorsum posterior to the dorsal fin. However, the new species differs from S. dubiosus in having a longer pelvic fin with the posterior tip of the depressed fin beyond vertical through the dorsal-fin origin (vs. usually not reaching to vertical through
dorsal-fin origin), longer pectoral fin, second dorsal- and third dorsal-fin rays, second anal- and third anal-fin rays, and greater interorbital width. Stolephorus taurus sp. nov. is closely related to Stolephorus baganensis Delsman, 1931 and S. dubiosus, although at least 2% mean p-distance divergence in the mitochondrial cytochrome c oxidase subunit I (COI) gene separates each of the three species. A phylogenetic reconstruction of the evolution of the number of prepelvic scutes within Stolephorus indicated that having six scutes was the most likely ancestral condition in the genus, and was later reduced in the evolution of Stolephorus to five or four scutes. One such reduction occurred recently in the lineage of Stolephorus taurus sp. nov.

Key words: Clupeomorpha, Taxonomy, Bay of Bengal, Stolephorus baganensis, Stolephorus tri.

Citation: Hata H, Lavoué S, Motomura H. 2022. A new species of the Bengal Spined Anchovy Stolephorus from the eastern Indian Ocean and redescription of Stolephorus dubiosus Wongratana, 1983, with comments on the evolution of prepelvic scute numbers within Stolephorus (Clupeiformes: Engraulidae). Zool Stud 61:58. doi:10.6620/ZS.2022.61-58.