Review of the Neotropical catfish genus Scoloplax (Pisces: Loricarioidea: Scoloplacidae) with comments on reductive characters in phylogenetic analysis
Proceedings of the Academy of Natural Sciences of Philadelphia
1989
Journal Article
141
181-212
Parque Nacional del Manu animals fish taxonomy systematics Pisces Loricarioidea Scoloplacidae Madre de Dios Bibliography
The description of Scoloplax dicra, originally known from the Rio Mamore/Guapore of Bolivia, is expanded on the basis of Brazilian and Peruvian material. Scoloplax distolothrix is described from tributaries of the Rio Negro, Rio Araguaia, upper Rio Xingu, all of the Rio Amazonas system of Brazil, and from the Rio Paraguai of Brazil and Paraguay. This species differs from other species of Scoloplax by the presence of three dorsal-fin rays, and by the combination of five pectoral-fin rays, four pelvic-fin rays, and five anal-fin rays. Scoloplax empousa is described from the Rios Parana, Paraguai, and Guapore of Brazil and is distinguisehd from all other Scoloplax by the combination of four dorsal-fin rays, five pectoral-fin rays, and six anal-fin rays. Scoloplax dolicholophia is described from tributaries of the Rio Negro, north of Manaus, Brazil. It shares the biramous mental barbels with S. distolothrix and S. empousa, but differs from all other species in aspects of head shape, the presence of four pectoral-fin rays, absence of mandibular barbels (present in S. distolothrix and S. empousa) and certain aspects of its osteology. Some implications of reductive features for systematic studies of Scoloplax and other miniature fishes are briefly discussed. The phylogenetic relationships of Scoloplax with other loricarioid catfishes remain unresolved.