Plesiolebiasini

Loureiro, Marcelo, Sá, Rafael de, Serra, Sebastián W., Alonso, Felipe, Lanés, Luis Esteban Krause, Volcan, Matheus Vieira, Calviño, Pablo, Nielsen, Dalton, Duarte, Alejandro & Garcia, Graciela, 2018, Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998, Neotropical Ichthyology 16 (3), pp. 1-20 : 3-5

Plesiolebiasini .

This tribe, revised by Costa (2011b), is diagnosed by seven unambiguous synapomorphies: 1. absence of an anterior expansion on the ventral process of the maxilla; 2. anterior portion of the entopterygoid not overlapping the autopalatine; 3. anterior retrorse process of lateral ethmoid contacting the main axis of the bone; 4. first two proximal radials of anal fin fused ( Fig. 5a ); 5. pelvic bones medially overlapped; 6. increase in number of neuromasts (between five and seven in the anterior, and four or more in the posterior sections) of supraorbital series; and 7. anal fin with basal region dark gray to black with a row of white to yellow spots. Besides these, Costa (2011b) mentions other synapomorphies that have independently arose in Rachovia maculipinnis Radda (Rachoviini) : bony flange on the posterior margin of the autopalatine, dorsal margin of the symplectic with an expansion towards entopterygoid, anterior portion of basihyal narrow, anterior proximal radials of the anal fin widened.

The clade is composed by five small (max. 50 mm SL) annual genera: Plesiolebias Costa , with eight species distributed in the Araguaia, Canabrava, Tocantins, and Xingú rivers in Brazil and eastern Paraguay; Papiliolebias Costa , with four species distributed in the western chacoan region in the Pilcomayo and Bermejo river basins (La Plata) and Mamoré and Madeira river basin (Amazonas); Maratecoara Costa , with four species distributed in the Tocantins, Xingú, and Canabrava river basins; Stenolebias Costa , with two species distributed in the Paraguay river basin; Pituna Costa , with six species distributed in the Araguaia, Tocantins, Paranaiba, and Canabrava basins. Costa (2011b) phylogenetic analysis supports Plesiolebias as the sister group to the rest of plesiolebiasines, while relationships among these are not clear due to low bootstrap support.

Figures

Fig. 5. Anterior section of anal fin of a. Papiliolebias bitteri, b. Pterolebias longipinnis, c. Ophthalmolebias constanciae; apr1-2 = proximal radials fused. Scale bar = 1 mm.