Brazilian ichthyologists Fernanda Martins and Francisco Langeani have described a new species of miniature plec in the genus Microlepidogaster.
Publishing the description of Microlepidogaster dimorpha in the latest issue of the journal Neotropical Ichthyology, the authors distinguish from congeners in having 29–30 vertebrae, 18–21 mid-dorsal plates, caudal peduncle depth 10.0–11.4% standard length, distance between the dorsal-fin origin and anal-fin insertion 19.4–23.8% standard length, length of unbranched pectoral-fin ray 20.0–23.8% standard length, head depth 43.4–53.1% head length, eye diameter 13.6–18.5% head length, front margin of the snout with a pair of rostral plates, nostril markedly wider in males than in females, the presence of the iris operculum (vs. absence), median plate series complete to the end of the caudal peduncle, presence of an axillary slit in the pectoral fin throughout life, and the first unbranched pelvic-fin ray longer in males than in females.
Microlepidogaster dimorpha displays considerable sexual dimorphism, more so than congeners. This character has led the authors to give it its specific epithet.
The new plec is known from the upper Paraná River drainage in southeastern Brazil.
For more information, see the paper: Martins, FO and F Langeani (2011) Microlepidogaster dimorpha, a new species of Hypoptopomatinae (Siluriformes: Loricariidae) from the upper rio Paraná system. Neotropical Ichthyology 9, pp. 79–86.