Three new species of Lebiasina (Characiformes: Lebiasinidae) from the Brazilian shield border at Serra do Cachimbo, Pará, Brazil

Lebiasina marilynae n. sp., L. melanoguttata n. sp., and L. minuta n. sp. are described from the headwaters of the rio Curuá, in Serra do Cachimbo, Pará, Brazil, and represent the only members of the Lebiasininae in the Brazilian Shied, so far. A close relationship among these species is proposed based on: 1) the presence of a pair of foramina through which the ramus palatinus of the facial nerve passes, a modification unique in Lebiasinidae and apparently in the Characiformes, 2) the enlargement of the extrascapular bone, 3) the absence of the secondary stripe, and 4) the nearly equal length of caudal-fin lobes. Lebiasina marilynae additionally differs from all congeners in having the primary stripe extending from the tip of the snout to the distal border of the caudal-fin peduncle, the possession of two series of dark blotches parallel to the primary stripe, and a rounded dorsal surface of the mesethmoid. Lebiasina melanoguttata and Lebiasina minuta additionally differ from all congeners in the absence of the primary stripe and the caudal blotch, and the presence of three longitudinal series of dark blotches at the base of the scales of series 3-5. Lebiasina melanoguttata differs from Lebiasina minuta in the absence of a dark blotch at the base of the median rays of the dorsal fin, second infrapharyngobranchial bearing conical teeth, the reddish overall coloration of the eye and fins, and the dark blotches never coalescing (vs. dark dorsal-fin blotch present; the second infrapharyngobranchial being edentulous; dark, olive green eyes, and the yellowish overall color of body and fins; and the dark blotches of longitudinal series 3 and 4 coalescing where scales of adjacent longitudinal series overlap). The occurrence of species of the Lebiasininae on the Brazilian Shield is discussed, and the distribution pattern of the species described herein is compared to that of other endemic species of the Serra do Cachimbo, a highly biodiverse area isolated from the rest of the Amazon basin.

Thanks are due to Richard P. Vari (USNM) and Cristiano Moreira (UNIFESP) for comments and suggestions to the manuscript. Specimens of Lebiasina melanoguttata (MZUSP 99609, MZUSP 99610 and MZUSP 99611) and Lebiasina marilynae (MZUSP 99607 and MZUSP 99608) were collected during the PIPE expedition to Serra do Cachimbo, a joint collaboration of MZUSP, ANSP and AUM, funded by All Catfish Species Inventory (NSF DEB-0315963). The author is grateful to Mark Sabaj Pérez, Nathan K. Lujan, José L. Birindelli, Leandro M. Sousa and Pedro Hollanda-Carvalho for their help and assistance during the field expeditions. Pictures of live specimens were provided by Mark Sabaj Pérez (Fig._1c; Fig._5c) and José L. Birindelli (Fig._5b); photos of preserved specimens were taken by Eduardo Baena (MZUSP). The author was financially supported by FAPESP (2006/04161- 5, 2010/19088-7, and 2011/50282-7).