Steindachneri-complex

[Fabien]

Hi,

I've just caught some A. steindachneri in Surinam.

I'd like to have a good idea of this complex, so could you tell me :

I know A. hippolytae, A. rupununi, A. steindachneri, A. aff. rupununi and A. sp. Rio Preto, is there another species ?

Could you tell me more for A. sp. Rio Preto. (from the upper Rio Madeira drainage ???)

Thanks, and sorry for my english.

 

[Mike Wise]

Fabien,

Your list seems fairly complete. A. cf. rupununi (the fish from the Rio Siapa of Venezuela) is probably a geographic population the Rupununi River form.

The steindachneri-group is in need of work. The typical rupununi seems more common in the Brazilian Rio Branco & is replaced by steindachneri in the Guyanian rivers. The problem is that, among fish collected along the border of Guyana & Brazil, we are seeing a steindachneri/rupununi form (A. cf. steindachneri) that shows some blending of features. I don't know if we have a single variable species or a superspecies composed of several closely related species. This is the same problem we have with what we now call A. agassizii and the taeniata/resticulosa forms.

As for A. sp. Rio Preto do Candeias, this is a rather unusual species. It has the dark markings of other steindachneri-group species, but unlike other members of the group it does not develop split vertical bars on the posterior half of the body. The metallic luster of the scale is less like that of other steindachneri-group species & more like those of other apistos. It shows very broad vertial bars on the flanks. In many respects the features seen on Rio Preto are a mix of the presumed ancestral lineages: steindachneri-, regani-, & pertensis-groups. It might represent a relic form of the original ancestral apistogramma before it started splitting into different species-groups. Its distribution corresponds with the presumed source for apistos, in the Brazilian Highlands.

 

[Fabien]

Mike,

Many thanks for these informations.

We could add to the list a particular rupununi form caught by A.Seva, U. Werner and D. Gottwald near Boa Vista. In France, we call it A. sp. "Roraino polis" or A. aff. rupununi "Rorainopolis" but, without studies, A. cf. rupununi could be a good name too.

Fabien

 

[Mike Wise]

I have not seen this fish, but Koslowski believes that the Roraimopolis (correct spelling of the name of the town) fish is only a geographic variant of A. rupununi & not a separate species. As I said, this species-group needs more work. I even have a photo of an A. steindacneri-like fish said to come from around Manaus (which I find hard to believe).

 

[Fabien]

Fabien,

The steindachneri-group is in need of work. The typical rupununi seems more common in the Brazilian Rio Branco & is replaced by steindachneri in the Guyanian rivers. The problem is that, among fish collected along the border of Guyana & Brazil, we are seeing a steindachneri/rupununi form (A. cf. steindachneri) that shows some blending of features. I don't know if we have a single variable species or a superspecies composed of several closely related species. This is the same problem we have with what we now call A. agassizii and the taeniata/resticulosa forms.

Hello,

The last special issue of the Datz about Apistogramma mentions Apistogramma sp. " Rupununi savanna " sympatric of A. rupunini in the South of Guyana and morphologically close of A. steindachneri while being genetically rather different. Thus, the authors think of a new species. Maybe a track to understand the forms of transition " rupununi-steindachneri " ---> "a superspecies composed of several closely related species" ???.

To complicate things, it seems that Surinam shelters at least a form of the steindachneri-group a little bit particular

I join a pic of a typical A. steindachneri of Surinam

And those of a particular form (ecotype, different species like Apistogramma sp. " Rupununi savanna "???), always from Surinam, You can see that it is less typical : See the variation of the shape of the spot on the sides of females, the truncated caudal of the males (even the very old ones)...

 

[Mike Wise]

Yes, you have a very interesting fish. Is it fully mature? It appears to be smaller than the Surinam A. steindachneri you also show. I base this on the size of the sand grains in both photos. The sand grains are smaller in the steindachneri photos. I assume that the grain size of the sand is the same in both photos. If the fish is fully developed, it has many similarities to A. sp. Rupununi-Savanna (= A. cf. steindachneri (Rupununi) in Koslowski 2002). I doubt that it is Rupununi-Savanna. It probably is a new & different form/species. Can you tell us more precisely where it was collected? I would also be interested in learning the river where the Surinam A. steindachneri was collected. We rarely see photographs of live specimens of A. steindachneri from Surinam.

 

[Fabien]

Both males on photos are in little meadows the same age old (I caught A. cf. steindachneri one month after A. steindachneri and they had the same size).

Now, 1 year and a half after photos (that is 2 years after their catching), they are always alive and these differences are still present. The caudal fin of the male A. cf. steindachneri present only two small buddings to the place of the usual strands.

 

[Fabien]

The real A. steindachneri is from a tributary of the Surinam River where is living with Nannacara anomala, Krobia guianensis, crenicihla cf. saxatilis, Rivulus agilae, Carnegiella striata some Characidae species...

The water is tinged, the current slow(during the dry season), 58µS.cm-1 and 25,6°C.

This creeks pours into an opened environment (savannas), or under poor forests installed on sedimentary deposit of white sand.

 

[Fabien]

Apistogramma cf. steindachneri was caught more in the West in the Coessewijn River which is situated on grounds of magmatic and metamorphic origin in a zone of primary forest. The association of species is almost teh same but the water is not also tinged.

 

[Mike Wise]

Thank you for the information. It appears that your A. steindachneri occurs in blackwater while the A. cf. steindachneri is from a clearwater stream.

 

[Fabien]

Mike

Effectively, the water is very different, it is moreover for it that I decided to go fishing in this to river... And I was not disappointed.

On the other hand I cannot become widespread in the other streams : I have to go back to this country soon...