My new cat from Papua New Guinea

[The.Dark.One, posts: 1438]

This is from the New Guinea shipment Pier Aquatics had in, along with Plotosus papuensis, Neosilurus brevidorsalis, N. equinus. Can't decide between N. ater or N. novaguineae. What do you guys think? The fish is about 20 inches.

[Jools]

Looks dissimilar to my N. ater. Aside from the fact my fish is black, it also has the much more of the back sprouting a fin.

Jools

[The.Dark.One, posts: 1438]

Going on the drawings in Freshwater Fishes of New Guinea N. ater and N. novaguineae both have the second dorsal starting quite far back on the body (as does N. ater in Field Guide to Freshwater Fishes of Australia) In the books N ater also has the high dorsal and the ventral fins quite close to the long pecs, so it seems to match N. ater in the books, but not N. ater in other photographs, that's why I went for N. novaguineae, but the first dorsal and pecs and ventrals seem to match the N ater in the books, so I'm a but puzzled.

[snowball, posts: 290]

I don't think the first or third pics on the previous page are N. ater. The body is not tall enough nor is the snout as angular as in N. ater.

N. brevidorsalis is a more likely choice for the second but that is just a quick guess.

I have a couple of books on NG fish which list quite a few of the cats but they are in storage in the attic and it will take a few days to dig them out.

[snowball, posts: 290]

Photo 1 I am not sure what it is. The closest plotosidae in appearance is Tandanus bostoki. The colour is similar as is the mouth shape and the secondary dorsal appears to carry further along the body as in Tandanus. Based on this I don't think it is a Neosilurus species. However T. bostocki is recorded (afaik) only in the south west of West Austrlia. Perhaps it is also found in New Guinea, or perhaps this is a different species of Tandanus? Or it might be a different genus altogether. If would be great if you can find out what river it was collected from.

Photo 2 does look like P. papuensis.

Photo 3 I think is Neosilurus mollespiculum. The dorsal & pectoral ray counts appear to match up as does the colouration description. I am sure it is not N. ater as I have seen many of them and they all have a different head shape, although the eyes are similar. Again my references only show this is as Australian (North Qld) but it is from a regional focused book so you never know where else it may turn up.


The Dark One: Your cat looks more like Oloplotosus mariae, however that is only known from a single species collected in the upper Fly-Strickland. But you never know, you may be lucky! Let me know if you want the ray counts.

[Silurus]

The Dark One: Your cat looks more like Oloplotosus mariae, however that is only known from a single species collected in the upper Fly-Strickland. But you never know, you may be lucky! Let me know if you want the ray counts.

Wrong. Steve's fish looks nothing like Oloplotosus mariae.

[snowball, posts: 290]

My error then as I didn't check what was already in the catelog. I compared it against a photo of a dead fish that does resemble Steve's fish more closely than the catelog pics.

Do you think it is a Plotosus species or something else?

[Jools]

So, I think this:

and the pic of Steve's above as an attachment are the same thing. I think the initial consensus is Neosilurus ater with a lot of doubt.

Does the attached key help?



Jools

[The.Dark.One, posts: 1438]

Not much as we can't count gill rakers from these photos but IMO the position of the second dorsal, the relative placement of the ventral fins and the golden colour lean towards N. ater. And I settled on N. ater for my pic too.

[Jools]

I think the golden colour should be discounted. There's a good chance many of these species do this.

However, could we not say, if the number of gill rakers is 20 then it is species A (due to character B) and if it's less than 13 then it is species C becuase of character(s) D.

I am interested in what you think B and D is.

Jools

[The.Dark.One, posts: 1438]

I'm not so sure the golden colour should be discounted. It has only been noted in one population of N. ater and if it was present in other species I would have thought it would have cropped up in the studies done by Australian and New Guinea ichthyologists, although I suppose it depends on how much they have been studied.

Let me check my books when I get home and see if I've another key. Which book is that key out of?

[Jools]

Which book is that key out of?

The fishes of the Indo-Australian Archipelago Vol II, Weber & Beaufort 1913.

Jools

[The.Dark.One, posts: 1438]

Ah yes, I have that (twice!).

Well meraukensis is a Porochilus now anyway, bartoni and perugiae are synonyms of brevidorsalis.

I have a more up to date key of the Australian ones (though that is from 1989) and one for the New Guinea ones (1991).

Some species overlap and are found in both islands. It will be easy to just reproduce the keys as they are but they may only be useful if the owner knows the origin of the fish. I could try and merge the two and come up with one but I can't vouch for its accuracy!

[Stackdeck, posts: 145]

Picked up one today as well , any guesses for the I.D ? It has since developed a slight mottled pattern upon settling down as well as a more yellowish colour.

[The.Dark.One, posts: 1438]

At first glance, N. brevidorsalis

[Stackdeck, posts: 145]

Thanks , will try to take a few more shots of it after it's more settled.