Pseudexostoma

Pseudexostoma
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Siluriformes
Family:	Sisoridae
Tribe:	Glyptosternina
Genus:	Pseudexostoma; X. L. Chu, 1979
Type species
	Glyptosternum yunnanensis; Tchang, 1935

Pseudexostoma is a

Irrawaddy (Dayinjiang River) in China.^[1] P. brachysoma is known only from the middle and lower Nujiang River. P. yunnanensis is only known from the upper Dayinjiang.^[2] These rivers were once connected, but are now separated. Also, the environment and temperature of the Nujiang River became greatly different between the northern and southern areas, leading to speciation.^[2]

Taxonomy

Glyptosternum yunnanesis was first described in 1935. However, due to its unique teeth, a separate genus Pseudexostoma was erected in 1979 for this species. The same year, a subspecies of P. yunnanensis was described, P. y. brachysoma. However, it has become apparent that these two groups represent different species. Also, a third species, P. longipterus, was described in 2007.

junior synonym of the latter.^[1]

Species

There are currently three recognized species in this genus:

Pseudexostoma brachysoma X. L. Chu, 1979
Pseudexostoma longipterus Zhou, Yang, Li & Li, 2007
Pseudexostoma yunnanensis (T. L. Tchang, 1935)

Description

These

caudal fin. The caudal fin is emarginate with the upper lobe smaller than the lower lobe. The lateral line is midlateral and complete.^[2]

Species of this genus are grey black on the dorsal surface and grey yellow on the ventral region; the caudal fin is grey black with an irregular, small, yellow patch in the middle and the other fins are grey yellow along the distal edge.

caudal peduncle, more teeth in the premaxillary tooth band (18–22 vs. 16–18) that are divided into two partially connected patches instead of two isolated patches.^[2] P. longipterus has longer pectoral, pelvic, and caudal fins as compared to its congeners.^[6]

References

^ ^a ^b Yang, K., Jiang, W., Chen, X., Zhou, W. & Yang, J. (2016): An integrative approach to reappraising species validity in Pseudexostoma (Teleostei: Sisoridae). Zootaxa, 4158 (3): 352–366.
^ ^a ^b ^c ^d ^e ^f Zhou, W., Yang, Y., Li, X. & Li, M.-H. (2007): A review of the catfish genus Pseudexostoma (Siluriformes: Sisoridae) with description of a new species from the upper Salween (Nujiang) basin of China. Raffles Bulletin of Zoology, 55 (1): 147-155.
^ ^a ^b Thomson, A.W. & Page, L.M. (2006): Genera of the Asian Catfish Families Sisoridae and Erethistidae (Teleostei: Siluriformes). Zootaxa, 1345: 1–96.
^ Froese, Rainer; Pauly, Daniel (eds.) (2016). "Pseudexostoma brachysoma" in FishBase. June 2016 version.
^ Froese, Rainer; Pauly, Daniel (eds.) (2016). "Pseudexostoma yunnanensis" in FishBase. June 2016 version.
^ Froese, Rainer; Pauly, Daniel (eds.) (2024). "Pseudexostoma longipterus" in FishBase. March 2024 version.

[Yang2016-1] Yang, K., Jiang, W., Chen, X., Zhou, W. & Yang, J. (2016): An integrative approach to reappraising species validity in Pseudexostoma (Teleostei: Sisoridae). Zootaxa, 4158 (3): 352–366.

[Zhou2007-2] ^ ^a ^b ^c ^d ^e ^f Zhou, W., Yang, Y., Li, X. & Li, M.-H. (2007): A review of the catfish genus Pseudexostoma (Siluriformes: Sisoridae) with description of a new species from the upper Salween (Nujiang) basin of China. Raffles Bulletin of Zoology, 55 (1): 147-155.

[Thomson2006-3] Thomson, A.W. & Page, L.M. (2006): Genera of the Asian Catfish Families Sisoridae and Erethistidae (Teleostei: Siluriformes). Zootaxa, 1345: 1–96.

[FB-4] Froese, Rainer; Pauly, Daniel (eds.) (2016). "Pseudexostoma brachysoma" in FishBase. June 2016 version.

[FBa-5] Froese, Rainer; Pauly, Daniel (eds.) (2016). "Pseudexostoma yunnanensis" in FishBase. June 2016 version.

[FBb-6] Froese, Rainer; Pauly, Daniel (eds.) (2024). "Pseudexostoma longipterus" in FishBase. March 2024 version.

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