Borneo: Sungai Malinau drainage (North Kalimantan)

[panaque]

In January I spent a few weeks in primary rainforest in Borneo, teaching a university field course. Among our many activities we sampled the fish in the small river next to our camp. I'll post more photos later but I thought I'd start with the only catfish species in our samples.
It's a

Glyptothorax

, but which one? Shape and size suggest

Glyptothorax major

but contrasting markings on body don't match. @Silurus?
Photos of two specimens:

[Silurus]

This looks very much like an unnamed species from Kalimantan Tengah (that is being named in a revision of Sundaic Glyptothorax). However, I do not recall this species being found north of the Mahakam River drainage.

[panaque]

This looks very much like an unnamed species from Kalimantan Tengah (that is being named in a revision of Sundaic Glyptothorax). However, I do not recall this species being found north of the Mahakam River drainage.

Thanks Silurus. We caught these roughly 400km north of the Mahakam. I can dig out gps coordinates if you like. Hope to return with appropriate permits to collect specimens within the next year.

[Richard B]

Have the pectorals been clipped in the first fish?

[panaque]

Have the pectorals been clipped in the first fish?

Yes, that one was caught by local fishermen who cut the pectorals before I could get to it because of the painful sting they can inflict. In fact they were very nervous about me handling the intact one. Perhaps there's a venom or nasty bacteria in the mucus of the spines.

[Richard B]

I've been spiked by Glyptos & whatever species it was, was ok. Perhaps this one is different? Can't remember which riverine Syno was the worst fish sting I received but it hurt like hell - however nowhere near as painful as a bite from a saucer bug (Ilyocoris cimicoides) - I cried like a baby; it was excruciating

[Shovelnose]

Perhaps there's a venom or nasty bacteria in the mucus of the spines.

I was once stung by an Akysis and it hurt quite a bit , there was a bit of swelling too. Strangely,the worst I have experienced are Schistura which draw blood every time I "mishandle" them. I am not talking about giant specimens but regular 2 inch ones.

[panaque]

This was the most common fish in our samples (and the main source of protein in our diet...). I believe it is Nematabramis everetti. A nice example of convergent evolution with South American hatchet fish in body shape, fin positioning, enlarged pectoral fins etc. Like hatchet fish they are clearly adapted to escaping predators by jumping long distances, and indeed the first specimen I saw was one that jumped into our prahu (canoe) on the way into the forest. The second (crappy) photo shows the long barbels that are characteristic of this species.

[kruseman]

I looked it up in The freshwaterfishes of North Borneo by Inger en Chin: Nematabramis everetti.
Males seem to develop small tubercles scattered over the body end rays of fins.
The book says this species is the most abundant cyprinid in the small streams of eastern Borneo.

[panaque]

Yep, that sounds about right