Surface and cave Ancistrus

Post by **Silurus** » 20 Feb 2006, 10:52

Reis, RE, E Trajano, & E Hingst-Zaher, 2006. Shape variation in surface and cave populations of the armoured catfishes Ancistrus (Siluriformes: Loricariidae) from the SÃ£o Domingos karst area, upper Tocantins River, Brazil. Journal of Fish Biology 68: 414â??429.

Abstract

Body shape of four distinct populations of Ancistrus cryptophthalmus from different caves in the SÃ£o Domingos karst area and the local epigean (surface) Ancistrus species were compared using geometric morphometrics. AngÃ©lica and Bezerra catfishes were closer to each other and successively to the studied sample of epigean catfishes than to Passa TrÃªs and SÃ£o Vicente I catfishes. Greater similarity between catfishes from the AngÃ©licaBezerra cave system to epigean catfishes than to other cave catfishes may represent a plesiomorphic feature. On the other hand, the present analyses allowed the distinction between Passa TrÃªs and SÃ£o Vicente I catfishes, which inhabited the same cave system. Topographic isolation due to the presence of several waterfalls interposed between the stream reaches where these catfishes live may explain such morphological differentiation. Also, the presence of a waterfall downstream of the reach where the AngÃ©lica sample was obtained may have contributed to the partial isolation of these catfishes from those living in Bezerra Cave. Differences in population sizes probably influenced the degrees of morphological differentiation observed among the cave populations. The mosaic distribution of character states indicated that the four populations of A. cryptophthalmus have evolved rather independently, but the continuous variation suggests a recent connection between these populations, perhaps with a limited gene flow. Considering other features such as reduction of eyes and pigmentation, and changes in body shape, a separate species status for the epigean and hypogean Ancistrus species from the SÃ£o Domingos karst area has been maintained.

bronzefry · Post by **bronzefry** » 20 Feb 2006, 13:32

Wonderful find! Are there any other known Siluriform cave species?
Amanda

Post by **Silurus** » 20 Feb 2006, 13:52

There are quite a number of cave catfishes (in the families Clariidae, Heptapteridae, Ictaluridae, Siluridae, and Trichomycteridae).

Daniel Machado · Post by **Daniel Machado** » 25 Feb 2006, 19:06

Bronzefry,

As Silurus said, there are some cave-dweling species of several families of catfishes... There's another Ancistrus species: Ancistrus formoso.

Best regards.

Daniel.

bronzefry · Post by **bronzefry** » 28 Feb 2006, 14:46

I find cave species quite interesting. Adaptations can happen so quickly!
Amanda