Hoplo and co?

[francoisMtl]

Hi,
I will need some help for identification.
Since a while, I have got 5 Callichthys callichthys, an import from Colombia (species 1). But they do not look like it and I wonder if they could be Hoplosternum of some kind:

Hoplosternum littorale

with its dot pattern most likely than

Hoplosternum magdalenae

.
More recently, I acquire 9 Hoplosternum littorale (species 2) but those ones look more like some Megalechis possibly

Megalechis picta

because of the white margin followed by darker band on caudal fin, for few of them the darker band maybe not obvious but the clear/white banding is.
The same day I got three Dianema longibarbis (species 3) which look like

Dianema longibarbis

.!!
From the caudal fin shape, none of the three species would look like Callichthys or Lepthoplosternum.

Here are some picture for some help in identification:
Species 1

Species 2

Species 3

[Bas Pels]

Hoplosternum has a forked tailfin, and looking at the pictures, I think your fishes have a forked fin. As far as I know, no other Callichtidea has such a fin.

As H littorale has a large distribution, I would not look too closely at any dot pattern. However, if the fishes reach 10 cm or more, they must be H littorale - and lookling at the ichtres, I would assume they are around this size.

The second does look like Mechalichthys to me, and the third Dianema indeed. I myself would not be surprized if Dianema would turn out to contain more than the 2 species we currently know. Just as a split of Hoplosternum littorale would not surprize me

[Jools]

Two is Megalechis picta. Can we see a closeup of the dorsal fin on species 3?

[francoisMtl]

Thanks to both of you!
I was thinking first one will not be H.littorale because they send it as Callichthys, priced it as Callichthys and on the same listing they were having H.littorale... Anyway they do the same kind of funny things with their corydoras.
The two largest of the first species are just above 10-11cm (4").
The largest ones of the second species are 8cm (>3").
The third species tops to 11-12cm (4"1/2), they have rather big eyes compare to the over two first species (hoplosternum and Megalechis).
Here are pictures of the dorsale fin of two of them (the last one has some fin issues and is been treated):

DianeL525.JPG (122.86 KiB) Viewed 1155 times

[francoisMtl]

Some more picture of what is suppose to be Dianema longibarbis.
Note: all the sizes mention above in previous texts are total length. So it will fit with

Dianema longibarbis

been 10cm sl.
Dorsal fin of the largest one

Pectoral shields of the largest one

Pectoral shields of the smallest one

View of two of the Hoplosternum littorale

It is not easy as I do not have

Hoplosternum punctatum

to compare with my

Dianema longibarbis

as they are both compare in description pages.
On a side note, link marked "here" in the Dianema description are not working from my computer.
I would still say that p[ectorale shield are juxtaposed, and dorsal fin has more of a triangular shape with soft rays decreasing in size versus Hoplo that would be a little more roundish... with dorsal fin spine maybe smaller and first soft ray smaller than the second one (in dianema first soft ray would be same size to longer than second one, making and overall triangular shape). Caudale fin may be more deeply fork in Dianema, more pointy, and clear of any dark mark.
All together, I would think these Dianema longibarbis are Dianema longibarbis.
What do you think?