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

André L Netto-Ferreira

doi:10.1590/s1679-62252012000300002

Abstract

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.

Highlights

The characiform family Lebiasinidae is endemic to the Neotropics and includes small sized freshwater fishes ranging from 15 mm standard length (SL) to 200 mm SL (Weitzman & Weitzman, 2003)
Lebiasina intermedia would be an exception to this distribution pattern, as its type locality was assigned by Meinken (1936) as “Mittlerer Amazonas bei Santarem” (Middle Amazon, near Santarém)
Standard length is presented in mm, all other measurements are presented as proportions of standard length (SL), except for subunits of head, which are presented as proportions of head length (HL)

Summary

Introduction

Netto-Ferreira et al (2011) described Lebiasina yepezi from the upper courses of the rio Negro, rio Branco and río Orinoco, and three new species of the Lebiasininae from headwaters of the rio Curuá (rio Xingu basin) are described . Both contributions provide evidence that the distribution of the subfamily in the Amazon basin is wider than previously noted, possibly due to lack of sampling in the headwaters of these tributaries of the Rio Amazonas. The relationships of the new species among the Lebiasininae are discussed

Material and Methods

Discussion

Literature Cited