Shape variation in surface and cave populations of the armoured catfishes Ancistrus(Siluriformes: Loricariidae) from the São Domingos karst area, upper Tocantins River, Brazil

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