Genus Oligosarcus .

The genus Oligosarcus was traditionally considered to be related with Acestrorhynchus (e. g. Menezes, 1969). Géry (1977), classified both genera in the tribe Acestrorhynchini of the subfamily Characinae . The phylogeny of Buckup (1998), however, did not yield a close relationship between these two genera, and Acestrorhynchus was excluded from the Characidae . The monophyly of Oligosarcus was not tested in the literature, although the species of this genus share some unique or unusual characters within Characidae, mostly involving their dentition (Menezes, 1969). The morphologically most generalized described species of this genus, Oligosarcus pintoi Campos is not herein analyzed, and probably some of the listed synapomorphies would apply to a subclade within Oligosarcus . According to the present analysis, the undescribed new species included in this clade (treated as an undescribed new genus and species by Mirande, 2009) should be described as a species of Oligosarcus .

Synapomorphies:

1. Temporal fossa (13): (1> 0) well developed. Paralleled in Brycon meeki, Bryconexodon juruenae, and Salminus brasiliensis .

2. Dorsal expansion of rhinosphenoid (48): (1> 0) absent. Paralleled in nodes 201 and 212 and in Agoniates anchovia .

3. Articulation between second and third infraorbitals (62): (0> 2) posteroventrally angled. Paralleled in the Characinae, in node 176, and in Bryconops melanurus and Hollandichthys multifasciatus .

4. Ectopterygoid teeth row (159): (0> 1) present. Paralleled in node 168 and in Acestrorhynchus pantaneiro, Distichodus maculatus, Hoplias cf. malabaricus, Serrasalmus maculatus, and Xenagoniates bondi .

5. Position of longitudinal cartilage dorsal to ectopterygoid (161): (0> 1) displaced laterally and separated from medial margin of mesopterygoid. Paralleled in node 211 and in Exodon paradoxus .

6. Bony lamellae bordering laterosensory canal of suprapreopercle (176): (0> 1) present. Paralleled in Markiana nigripinnis .

7. Number of branched anal-fin rays (288): (1> 0) 24 or less. Reversal of synapomorphy 5 of the Characidae . Paralleled in nodes 200 and 277 and in Acestrorhynchus pantaneiro and Iguanodectes geisleri .

8. Uroneurals (306): (0> 1) two pairs. Reversal of synapomorphy 15 of node 205. Paralleled in the Tetragonopterinae, in node 276, and in Bryconamericus scleroparius, Galeocharax humeralis, and Markiana nigripinnis .