New Creteuchiloglanis

[Silurus]

Sarkar, UK, DR Tenali, R Chandran & RK Singh, 2024. Discovery of a new glyptosternine catfish Creteuchiloglanis nuthemuensis (Siluriformes: Sisoridae) from the Duphlokho River, Arunachal Pradesh, India. Biology Bulletin Reviews doi: 10.1134/S2079086424020099.

Abstract

In the present communication a new glyptosternine catfish Creteuchiloglanis nuthemuensis, is described from the Duphlokho River in West Kameng district, Arunachal Pradesh, India, which is a headwater of the Kameng River in the Brahmaputra basin. The new species is eminent from all closely related species of the genus by a distinct combination of the subsequent characteristics: presence of long pectoral fin extending over the pelvic fin origin and its reaching posterior end of dorsal fin base, body depth at anus 12–15.8% SL, predorsal length 34.5–35.9% SL, pelvic fin length 16–19.8% SL, adipose fin base length 28.3–33.3% SL, caudal peduncle depth 6.6–7.6% SL, absence of pinnate-like rays on the first branching ray’s anterior margin and second simple ray of anal fin, head depth 9.9–11.3% SL, and eye diameter 5.3–7.5% HL. This is the sixth Creteuchiloglanis species described from the Brahmaputra River basin.

[bekateen]

As I added this new species to the CLOG and endeavored to create a (hopefully) accurate river system to near its location, I noticed a minor discrepancy in the type locality as presented in the paper. I think it's probably insignificant since most GIS data have a margin of error, but I'm not totally sure: In the text of the paper, the type locality coordinates are 27.157056, 92.2795278 (27°08'85.4'' N, 92°16'46.3'' E), but the paper's illustration plots the type locality at 27.11972, 92.26794, about 4 miles southwest of the textual coordinates. Making matters more difficult was that the river which includes both of these coordinates and also runs parallel to the Trans-Himalaya Highway in this area is not named on any of the maps I could track down. I infer that either this river is the Duphlokho River, or else the Duphlokho River is a branch off of whatever river this is.

This then also got me updating the other Creteuchiloglanis, and I got stuck on

Creteuchiloglanis kamengensis

. It's from the "Norgum River at Kalaktang." I had no trouble finding Kalaktang, which is further southwest from the type locality of

Creteuchiloglanis nuthemuensis

; but for the life of me, I can't track down the Norgum River on any map I could track down. I don't know if it's a tributary of the Duphlokho, or if it's an unrelated river approaching Kalaktang from the South or West, independent of any flow originating to the East from the Kameng. Both rivers I saw on maps flowing near or through Kalaktang weren't labeled with names.

Not necessary to solve I suppose, but I've felt for a while that Asian catfishes have less careful mapping than do South American catfishes . I imagine that's because the former aren't as big a part of the aquarium trade. I've been trying to fill that in a little bit here and there... Hope nobody minds. I realize it blows up the list of bodies of water, and in my unfamiliarity I may get some tributary connections wrong, but I try to be meticulous and hopefully most everything is roughly accurate.

Cheers,
Eric

[bekateen]

For a fleeting moment, I thought I had the Norgum River solved, but no. I found two publications about invertebrates, each collected along the Norgum river below a specific village. In one case, the Dengzi Village. In the other case, the Betchilling Village. Combining those two references with the Creteuchiloglanis report of being in the Norgum near Kalaktang, I though I had solved the Norgum to be this river running beside the road from Betchilling to Kalaktang. But then another website (https://www.mindat.org/feature-1278887.html) told me different. It said the river running along the road is called the Bhairabi River. So I have no idea where the Norgum is.

Additionally, that same website shows that the river I thought was the Duphlokho is called the Heliu1, which the map shows joins the Heliu by the city of Rupa, just after the Tenga River splits. But it's not that simple either. The mindat website only labels the Heliu1 towards Shergaon, but then doesn't name it beyond Shergaon to Kalaktang.

Going back to the Duphlokho issue for a moment: If that river to Shergaon is the Heliu1, then maybe the Duphlokho is the branch shown where the map (in the Creteuchiloglanis paper) shows the pin for the type locality.

... Ugh...

Cheers, Eric