Tetragonopterus, CUVIER, 1816

TETRAGONOPTERUS CUVIER, 1816 View in CoL

Type species: Tetragonopterus argenteus Cuvier, 1816 .

New combinations: Tetragonopterus daguae ( Eigenmann, 1913) , comb. nov.

Diagnosis: Tetragonopterus is diagnosed by the following combination of characters: a deep and compressed body, two rows of premaxillary teeth with the inner row generally consisting of five or more teeth, a flattened prepelvic area that is bounded laterally by well-marked angles and a complete lateral line with an anterior portion that is strongly bent downwards ( Eigenmann, 1917). Species of this genus are also recognizable, as mentioned by Silva et al. (2017), by a deep body, complete lateral line and the presence of pentacuspidate teeth in the inner premaxillary row.

Tetragonopterus daguae does not share with the remaining species in the genus the branched name in black were analysed from both morphological and molecular data; taxa in blue from several DNA markers plus some morphological characters coded from literature; taxa in red from just one DNA marker (COI) plus some morphological characters coded from literature; and taxa in green analysed only from morphological data. The expression ‘best searches’ refers to the calculations of overall parsimony explained in the text.

laterosensory canal in the sixth infraorbital and has four supraneurals instead of the three proposed by Silva et al. (2017) to be synapomorphic for Tetragonopterus . However, the coded specimen of T. argenteus had four supraneurals, suggesting an intraspecific variation that could be present also in other species of the genus.

Synapomorphies: With the addition of Tetragonopterus daguae , the genus is supported by: ten ethmoid cartilage distant from lateral ethmoids (40:1), sphenotic spine long and reaching hyomandibular dorsal margin (47:1), supraoccipital spine extended dorsal to entire neural complex of Weberian apparatus (61:0), laterosensory pore anterior to dilatator fossa oriented dorsomedially (115:0), five teeth in the inner premaxillary series (182:0), dentary teeth abruptly decreasing in size (207:1), metapterygoid foramen for passage of the pseudobranch artery as an oblique canal through the metapterygoid (228:1), axis of supraneurals dorsally bifurcated (396:1), bony lamellae developed on supraneurals (397:1) and the presence of iii dorsal-fin rays with the anterior one visible only in c&s specimens (404:1).

STEVARDIINAE : ERETMOBRYCONINI