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I figured the forum has the largest collection of catfish heads outside of a JMIH, so here's a question I pose for you:

Do you think the heads of the two Mystus species presented below represent two different species?



Other than the size of the eye, are the shapes of the snouts sufficiently different to distinguish the fishes as belonging to two species?

I figured if the differences are readily apparent to the layman, then it should not be too difficult to convince scientists the same.

Silurus wrote:Do you think the heads of the two Mystus species presented below represent two different species?

Overall, on the basis of these two specimens, I would say yes.

Silurus wrote:are the shapes of the snouts sufficiently different to distinguish the fishes as belonging to two species?

Barely. The mouth of the top fish appears slightly more inferior, but that could be due to differences in how open the mouth was when the fish was preserved?

Silurus wrote:Other than the size of the eye

Not just the shape and relative size of the eye, but the position. Take a horizontal line from the base of the maxillary barbel in both fish, and look at the position of the eye in relation to that line.

Silurus wrote:I figured if the differences are readily apparent to the layman, then it should not be too difficult to convince scientists the same.

Sounds like you had a bad review on a manuscript?

racoll wrote:Sounds like you had a bad review on a manuscript?

Haha. I have barely started on the manuscript. I just thought I'd run it through the forum to see if this is something worth pursuing further.

Thanks for the input.

Is the shape of the posterior of the operculum different as well, slightly concave in the upper.(closest to the pectoral)

Birger

Assuming these are either "typical of series" or "similar size" (or both), I'd say the eye position as well as shape is enough to separate these two. The upper one reminds me of the eyes of M. mysticeatus, but maybe it's a bit higher...

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Mats

are these fish the same size?

because if one is much smaller than the other, the slight differences might be caused by growing up...

Head length relative to the predorsal area is different IMO (lower fish has a longer head).

From what I can see, I would think yes.


Ps : I sure hope it is an Indian species.

Input from this forum has convinced me to go ahead with the study, and the manuscript has been accepted for publication in Zootaxa.

Sorry Balaji, this is an Indochinese species.

Congrats. Looking forward to seeing it!

The new species has been described as Mystus velifer.

Being a layman, myself, besides the eye, the biggest thing that screams different species was the gill cover.