Description of a new species and phylogenetic analysis of the subtribe Cynopoecilina, including continuous characters without discretization (Cyprinodontiformes: Rivulidae)

Abstract

A new species of the subtribe Cynopoecilina is described from the rio Gravataí basin, laguna dos Patos system, southern Brazil. The relationships of the new species among taxa of the subtribe Cynopoecilina is discussed based on two analyses: one using 71 discrete characters and other with the addition of six continuous characters analyzed without discretization. The addition of the continuous characters resulted in the first fully resolved phylogenies for Cynopoecilus and Leptolebias species, not obtained in the analysis including only discrete characters. The new species is assigned to Cynopoecilus as sister group to the remaining species of the genus. A new diagnosis is proposed for Cynopoecilus to accommodate the new species. The resulting phylogeny indicates that the occupation of the grasslands of the Pampa biome by the species of Cynopoecilus occurred along the evolution of the genus and that this event was significant for the diversification of the genus.

Microanatomical diversification of the zona pellucida in aplochelioid killifishes

“…A total of 16 binary characters were coded for each species (Table II) and entered to a nexus file using Mesquite 3.0 (Maddison & Maddison, 2015). A strict consensus phylogeny that included the sampled taxa was coded in Mesquite by hand from several phylogenetic studies (Costa, 2010a(Costa, , 2011(Costa, , 2013(Costa, , 2014a(Costa, , b, 2015Dorn et al, 2014;Ferrer et al, 2014;Furness et al, 2015;Pohl et al, 2015). These studies used a diversity of morphological and molecular data for phylogenetic inference.…”

Seasonal dynamics in community structure, abundance, body size and sex ratio in two species of Neotropical annual fishes

“…The occurrence of Cynopoecilus spp. in a grassland biome is evolutionarily recent (Ferrer et al, 2014).…”

A new species of inseminating seasonal killifish of the Cynopoecilus melanotaenia complex from southern Brazil (Cyprinodontiformes: Rivulidae)

“…Among them, the frontal squamation pattern consisting of E-scales medially overlapped is unique among cynopoeciline killifishes, which have been diagnosed by the E-scales medially separated by an interspace (Costa 1998). Another striking feature of C. feltrini is the orangish red branchiostegal region in males, a condition not found in other congeners of the C. melanotaenia complex, but similar to the red branchiostegal region of C. notabilis (Ferrer et al 2014). Finally, all species of the C. melanotaenia complex may be easily recognised among other cynopoecilines by the presence of numerous dark brown spots along the dorsum, but in C. feltrini these spots are restricted to region above the opercular region.…”

“…It consists of a series of minute rays on the anterior part of the fin, forming an inseminating structure (Costa 1995, Costa 1998). In addition, Cynopoecilus may be easily diagnosed by the unique colour pattern occurring in all included species, consisting of a dark reddish brown to black stripe along the lateral midline of the body and another between the pectoral-fin base and the posterior end of the anal-fin base (Costa 1998, Costa 2002, Ferrer et al 2014). …”

“…After larger collections made between 1997 and 1999, Costa (2002) provided the first taxonomical revision of Cynopoecilus , recognising five species: C. melanotaenia (Regan 1912), the type species of the genus, and C. fulgens Costa 2002, C. intimus Costa 2002, C. multipapillatus Costa 2002, and C. nigrovittatus Costa 2002; but a unpublished taxonomic revision of the genus by the first author indicates that C. multipapillatus is a synonym of C. fulgens . These species form a morphologically homogeneous group, herein called the Cynopoecilus melanotaenia complex, with all included species highly differing from another congener recently described by Ferrer et al (2014),  C. notabilis Ferrer et al 2014. Among several diagnostic characters, species of that complex have the dorsal-fin origin in a vertical just anterior to anal-fin origin in males ( vs. anterior to pelvic-fin insertion in C. notabilis ), caudal fin rounded to sub-truncate in males ( vs. lanceolate), unpaired fins hyaline in males, with pale spots or spots absent ( vs. yellow with dark red spots), absence of a dark red stripe on the basal portion of the anal fin in males ( vs. present), and flank in females without bars ( vs. with bars).…”