Abstract
Hypostomus rhantos is described for a uniquely pigmented species of loricariid catfish from the upper Río Orinoco of Amazonas, Venezuela. Hypostomus rhantos can be separated from all other Hypostomus except H. micromaculatus by having its head and dorsal and lateral surfaces of body densely covered in very small spots (greater than 15 spots on the first plate in the dorsal series of specimens less than 100 mm SL vs. less than 10; greater than 30 spots in specimens greater than 100 mm SL vs. less than 15). The new species is distinguished from H. micromaculatus by having round spots (vs. longitudinally oval) that are unordered (vs. in longitudinal lines), by having well-developed keels on the lateral plates (vs. keels weak), by the presence of a ridge on the pterotic that is contiguous with the supraorbital ridge (vs. pterotic ridge absent), and by having the abdomen fully plated (vs. partially plated or naked).References
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