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Absolutely awesome, mr. Collins, you made my day!!
Keep up the good work and share some more please.
Btw: any sightings of gymnotids?

racoll wrote:

Tatia

(same as above)

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Looks a lot like an (off colour)

racoll wrote:

Tatia brunnea

? (clearwater igarapé forest stream)

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Determination seems correct imo.

Marc van Arc wrote:any sightings of gymnotids?

No photos, but we had small Gymnotus, nice big Gymnorhamphichthys, very pretty Steatogenys (the look so similar to the that you often can't tell them apart and first glance in the net), and Eigenmannia. No really crazy ones like Orthosternarchus though.

Looks a lot like an (off colour) Tatia musaica

It does rather, but the dark distal margin to the caudal is pretty distinctive in this fish though. Maybe part of the same species group?

racoll wrote:It does rather, but the dark distal margin to the caudal is pretty distinctive in this fish though. Maybe part of the same species group?

I'm a bit at a loss as to what a dark distal margin is, but if it has anything to do with a tail pattern (probably not....) it could also be - in which case it is obviously from a different genus, yet from the same subfamily.

Awesome work Racoll. Really appreciate you giving the region of the river you found the fish in. Thank you for sharing.

Marc van Arc wrote:I'm a bit at a loss as to what a dark distal margin is, but if it has anything to do with a tail pattern (probably not....) it could also be Centromochlus macracanthus - in which case it is obviously from a different genus, yet from the same subfamily.

So "dark distal margin" just refers to the colour pattern of the tail, yes. Basically a fancy way to say it has a black edge.

Marc van Arc wrote:it could also be Centromochlus macracanthus - in which case it is obviously from a different genus, yet from the same subfamily.

I still don't see the point in splitting and . Together they are a well diagnosed group with relatively few species. The two genera can only be told apart by experienced systematists with morphometrics and cleared and stained material to hand. Heck, even Vari & Ferraris (2013) had problems with T. musaica. I'm all for nomenclature reflecting phylogeny, but not when it comes at the expense of a usable and easily communicable classification.

racoll wrote:I still don't see the point in splitting

Tatia

and

Centromochlus

. Together they are a well diagnosed group with relatively few species. The two genera can only be told apart by experienced systematists with morphometrics and cleared and stained material to hand. Heck, even Vari & Ferraris (2013) had problems with T. musaica. I'm all for nomenclature reflecting phylogeny, but not when it comes at the expense of a usable and easily communicable classification.

I couldn't agree more, although in my case it's more a matter of gut feelings combined with observations than a scientific approach, because I simply lack the knowledge.
Imho Mees' and Ferraris' systematics were workable; Soares-Porto made things rather complicated.
As a kind of lifetime auchenipterid keeper I should be able to distinguish genera by just looking at them, but I am often unable to do so in the case of Tatia vs Centromochlus.

Marc van Arc wrote:As a kind of lifetime auchenipterid keeper I should be able to distinguish genera by just looking at them, but I am often unable to do so in the case of Tatia vs Centromochlus.

Quite!

This is the type of below. To me the snout looks flatter and longer than in the fish I collected. The upper jaw appears distinctly more prognathous in my fish.
Heok Hee (or anyone else), what do you reckon?



Here's another shot of a smaller one where you see the jaws better:

The relative jaw lengths appear different, but I'm not so sure about the snout. They seem the same length; your fish has what seems to be a more curved predorsal profile, but this difference might be due to dehydration in the preserved state of the type.

Thanks HH. I guess this is a situation where you really need both materials in hand to compare. Not sure if there's enough evidence here to make this work chasing up.

Any other photos of the denticetopsis and helogenes?

Here's a smaller . Only other pictures of are slightly more out-of-focus shots of the same fish.

racoll wrote:

Cetopsis coecutiens

(channel of main river)

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Cetopsis oliveirai

(channel of main river)

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Leptodoras copei

or Leptodoras cf. copei (channel of main river)

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The whale catfish or candiru acu reminds me of River Monsters.