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Morphological Adaptations of the Texas Blind Catfishes Trogloglanis pattersoni and Satan eurystomus (Siluriformes: Ictaluridae) to Their Underground Environment
Thomas G. Langecker and Glenn Longley
Vol. 1993, No. 4 (Dec. 28, 1993), pp. 976-986
Stable URL: http://www.jstor.org/stable/1447075
Page Count: 11
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The blind catfishes Trogloglanis pattersoni and Satan eurystomus occur in deep artesian waters of the Edwards Aquifer in southwest Texas. The origin of their cavernicolous evolution was traced back to Pliocene or Miocene. Both blindcats exhibit extreme and uniform regressions of pigmentation, eyes and their correlated brain centers, and the pineal organ. They also evolved a hypertrophy of the saccus vasculosus, the telencephalon, and the cerebellum. The effects of high hydrostatic pressure are reflected by the evolution of the morphological "deep sea syndrome" in both blindcats. They exhibit a total regression of the swimbladder, an accumulation of large adipose deposits, and furthermore a series of apparently paedomorphic traits: a small body size, an enlarged head, a weakly ossified skeleton, and reduced muscles. Besides these convergent adaptations, both species differ in morphological features that suggest adaptations to distinct ecological niches.