Glyptosternoid biogeography

[Silurus]

Ma, X-H, J-L Kang, W-T Chen, C-J Zhou & S-P He, 2015. Biogeographic history and high-elevation adaptations inferred from the mitochondrial genome of glyptosternoid fishes (Sisoridae, Siluriformes) from the southeastern Tibetan Plateau. BMC Evolutionary Biology 15:233.

[BomNya]

Nice paper, thanks for sharing.

What are peoples thoughts on the dispersal of glyptosternoids back downstream via the Brahmaputra (and other drainages mentioned)? Has anyone here ever encountered glyptosternoids in the main Brahmaputra River?? I have certainly encountered them in the torrents of the Brahmaputra basin, but never in the broad slow rivers of the plains. I wonder if their distribution in the eastern himalayas is not wholly dictated by vicariance (followed by localized dispersal of course). If there was a downstream dispersal, we would also expect to find all of these genera in the southern tributaries of the Brahmaputra. I know Exostoma is down there, but that would make sense as they are a more basal group (pre-uplift-driven radiation according to this paper). What about Oreoglanis, Creteuchiloglanis?

Thoughts?

Tashi Dalek,
Ryan

[Silurus]

This is from a soon-to-be-published paper on sisorid phylogeny:

"Although the restriction of a large bulk of glyptosternine diversity to the southern arc of the Tibetan Plateau suggests that the uplift of the plateau played a major role in their diversification, there is evidence to suggest that the uplift was not responsible for the diversification of all glyptosternines (minus Pseudecheneis) from all other sisorids. Glyptosternon, the least derived member of all glyptosternines (except Pseudecheneis) is also found in river drainages draining the south face of the Himalayas in the northern part of the Indian subcontinent and the upper reaches of the Amur Darya and Syr Darya river drainages (Berg, 1949), which drain the northern edge of the Pamir range.

From a strict vicariant point of view, it seems more plausible that ancestral glyptosternines were more widely distributed throughout the northern part of the Indian subcontinent and that the formation of the Himalayan orogenic belt during the collision of India with Asia, rather than the uplift of the Tibetan plateau, might be responsible for the initial diversification of the glyptosternines (He et al., 2001). Although it is impossible to conclusively discount a dispersal-based scenario (i.e. the fishes dispersed to their present western and southern limits from an origin along the southern edge of the Tibetan Plateau), the biology of glyptosternines suggests limited dispersal ability on their part. Glyptosternine catfishes have strict habitat requirements and are found in an altitudinal range of 950–3600 m asl (Wu & Wu, 1992; Shrestha, 1994), so the only way that they could have dispersed from the southern edge of the Tibetan Plateau to the western edge of the Tian Shan range would be via stream captures."

[BomNya]

Interesting! Look forward to reading it.

Although, I have found glyptosternines (depending on what you consider glyptosternines) below 950m. Some as low 350-400 I think. But I agree with the point being made. Will publish soon enough ;)