The genus Notholebias was assigned to three species which are transferred from the Leptolebias genus. The type species of this new genus is Notholebias minimus (Myers, 1942).

Furter components of Notholebias are N. fractifasciatus and N. cruzi.

A phylogenetic analysis based on morphological characters indicates that Leptolebias Myers, 1952, a genus of small killifishes highly threatened with extinction, from Brazil, is paraphyletic. As a consequence, Leptolebias is restricted in this study to a well-supported clade that includes Leptolebias marmoratus (Ladiges, 1934), Leptolebias splendens (Myers, 1942), Leptolebias opalescens (Myers, 1942), and Leptolebias citrinipinnis (Costa, Lacerda & Tanizaki, 1988), from the coastal plains of Rio de Janeiro, and Leptolebias aureoguttatus and Leptolebias itanhaensis sp. nov., from the coastal plains of São Paulo and Paraná, in southern Brazil. Leptolebias is diagnosed by three synapomorphies: a caudal fin that is longer than deep, a single anterior supraorbital neuromast, and dark pigmentation that does not extend to the distal portion of the dorsal fin in males. A key is provided for the identification of species of Leptolebias. Three species formerly placed in Leptolebias, Leptolebias minimus (Myers, 1942), Leptolebias fractifasciatus (Costa, 1988), and Leptolebias cruzi (Costa, 1988), are transferred to Notholebias gen. nov., which is hypothesized to be the sister group to the clade comprising Leptolebias, Campellolebias Vaz-Ferreira & Sierra, 1974, and Cynopoecilus Regan, 1912.

Notholebias is diagnosed by two synapomorphies: a narrow basihyal and the presence of iridescent bars on the caudal fin in males; and three features interpreted as plesiomorphic, but not occurring in Leptolebias, Campellolebias, or Cynopoecilus, the presence of dermosphenotic, well-developed contact organs on the pectoral fin in males, and an opercular region with red bars in males. ‘Leptolebias’ leitaoi, a species from Bahia, in north-eastern Brazil, is considered as having an uncertain phylogenetic position, as all known preserved material is presently lost, and the species may be extinct.

The monophyly of the group comprising the southeastern South American seasonal killifish genera Cynopoecilus Regan, 1912, Campellolebias Vaz- Ferreira & Sierra, 1974, and Leptolebias Myers, 1952 was first proposed by Costa (1990a). This assemblage, named as the subtribe Cynopoecilina by Costa (1990b), was subsequently tested and corroborated by more detailed phylogenetic analyses, based both on morphology (Costa, 1998) and molecular data (Hrbek & Larson, 1999; Murphy, Thomerson & Collier, 1999). Cynopoecilus and Campellolebias constitute an equally well-corroborated clade of internally inseminating killifishes (Costa, 1990a, 1998; Hrbek & Larson, 1999; Murphy et al., 1999), which have been included in recent taxonomic revisions (Costa, 2002a, 2006a). Leptolebias, a genus of small, externally inseminating species (maximum adult size ~20– 30-mm standard length), is, however, still poorly diagnosed. All species presently placed in Leptolebias are endemic to the coastal plains of eastern, southeastern, and southern Brazil (Costa, 2003). They inhabit seasonal pools of dark acidic water (pH 3.5– 6.0), which are often found in dense forests.

Literature:

Costa, W.J.E.M., 2008. Monophyly and taxonomy of the Neotropical seasonal
killifish genus Leptolebias (Teleostei: Aplocheiloidei:
Rivulidae), with the description of a new genus. Zoological Journal of the Linnean Society, 2008, 153, 147–160. (11 figs.)

Behaviour:

It can get rather cool in the area were Leptolebias and Notholebias lives during wintertime. Therefore they need to be held cool during there life as low as 18 C with a maximum of 23 C. In the summer temperatures can rise also very high you could say and that is thrue. Originally however, these species lived there live's in area's covered with forrests. Nowadays most forrest is disappeared by urbanisation or replaced by agricultured land, only a few habitats are left untouched in hilly terrain. During warmer periods the forrests canope protected there habitats from getting to warm. So, urbanisation has in many ways reduced the habitats and living conditions of Leptolebias and Notholebias and other similar genera.