Xenurolebias (Costa 2006)  (4 Arten)

Abstract

This study is focused on a poorly known genus of small killifishes, Xenurolebias, comprising species uniquely living in temporary pools of the Atlantic Forest in the coastal plains of eastern Brazil (a region undergoing intense deforestation). Xenurolebias comprises two nominal, morphologically similar species, but some variability among populations suggests it represents a species complex. In order to delineate species limits, a taxonomic revision was conducted combining two different approaches: (i) a character-based approach using morphological variation (colour patterns, fin morphology, meristic and morphometric data) and (ii) a tree-based approach using mt-DNA (tRNA-Met, tRNA-Gln and ND2). The results strongly supported four species: X. myersi (Carvalho) from the Itaúnas river basin and adjacent smaller drainages; X. izecksohni (Cruz) from the Barra Seca river basin; X. cricarensis Costa, sp. nov., from the São Mateus river basin; and X. pataxo Costa, sp. nov., from the Mucuri, Itanhem and Jucuruçu river basins. Recognition of four distinct species in Xenurolebias should change views about the conservation of the species, one of which (X. pataxo) is seriously endangered and should be considered a priority for conservation.http://zoobank.org/urn:lsid:zoobank.org:pub:8485DD00-3F30-4C9F-9682-62C4718D53D9

Xenurolebias cricarensis W. J. E. M. Costa, 2014 

Integrative taxonomy and conservation of seasonal killifishes, Xenurolebias (Teleostei: Rivulidae), and the Brazilian Atlantic Forest. Systematics and Biodiversity, 12 (3): 350-365. 

Xenurolebias pataxo W. J. E. M. Costa, 2014 

Integrative taxonomy and conservation of seasonal killifishes, Xenurolebias (Teleostei: Rivulidae), and the Brazilian Atlantic Forest. Systematics and Biodiversity, 12 (3): 350-365.

Xenurolebias izecksohni da Cruz, 1983

Uma nova Especie de Cynolebias do Estado do Espirito Santo, Brasil (Pisces, Cyprinodontidae). Papeis Avulsos Zool., 35 (6): 74, figs. 1-3.

Type locality: Reserva Florestal da Companhia Vale do Rio Doce, município de Linhares, Espírito Santo state, Brasil.

Xenurolebias myersi A. L. de Carvalho, 1971

Um novo Peixe anual do Estado do Espirito Santo (Pisces, Cyprinodontidae, Rivulinae).

Revta. Brasil Biol., 31 (3): 401, figs. 1-3.

Type locality: 18 km from Conceiçao da Barra, towards Itaunas, northeastern state of Espirito Santo, Brasil.

Xenurolebias myersi

Descriptive morphology and phylogenetic relationships among species of the Neotropical annual killifish genera Nematolebias and Simpsonichthys (Cyprinodontiformes: Aplocheiloidei: Rivulidae)    Costa 2006

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Abstract

Structures of the external morphology and skeleton of the annual fish genera Nematolebias and Simpsonichthys are described and illustrated. Phylogenetic relationships among all included species of both genera and other cynolebiatins are estimated, based on 116 morphological characters in a total of 50 terminal taxa. Nematolebias is hypothesized to be the sister group of a clade including Simpsonichthys, Austrolebias, Megalebias, and Cynolebias, which is diagnosed by ventral portion of mesopterygoid not overlapping quadrate, third neural spine approximately as wide as fourth neural spine, ventral condyle of coracoid narrow, scales slightly extending over anal-fin base, loss of vomerine teeth, loss of neuromast anterior to infraorbital series, ventral process of the angulo-articular short and narrow, and dorsal portion of cleithrum elongated. Simpsonichthys is divided into five subgenera, including Spectrolebias, previously considered a separate genus, Simpsonichthys, and three new subgenera, Xenurolebias, Ophthalmolebias, and Hypsolebias. Monophyly of Simpsonichthys is supported by a small pointed dorsal process on the palatine, unbranched fin rays on the tip of the dorsal and anal fins in males, and frontal E-scales overlapped.

A new genus of miniature cynolebiasine from the Atlantic Forest and alternative biogeographical explanations for seasonal killifish distribution patterns in

South America (Cyprinodontiformes: Rivulidae)  (Costa 2014)

Vertebrate zoology 64 (1): 23–33 / 16.05.2014

Abstract The analysis of 78 morphological characters for 16 species representing all the lineages of the tribe Cynopoecilini and three out-groups, indicates that the incertae sedis miniature species ‘Leptolebias’ leitaoi Cruz & Peixoto is the sister group of a clade comprising the genera Leptolebias, Campellolebias, and Cynopoecilus, consequently recognised as the only member of a new genus. Mucurilebias gen. nov. is diagnosed by seven autapomorphies: eye occupying great part of head side, low number of caudal-fin rays (21), distal portion of epural much broader than distal portion of parhypural, an oblique red bar through opercle in both sexes, isthmus bright red in males, a white stripe on the distal margin of the dorsal fin in males, and a red stripe on the distal margin of the anal fin in males. Mucurilebias leitaoi is an endangered seasonal species endemic to the Mucuri river basin. The biogeographical analysis of genera of the subfamily Cynolebiasinae using a dispersal-vicariance, event-based parsimony approach indicates that distribution of South American killifishes may be broadly shaped by dispersal events. The analysis supports south-eastern Brazilian coastal plains as the centre of dispersal for cynolebiasine killifishes. Alternative biogeographical explanations are compared and possible dispersal routes and means of dispersal are discussed.