Xenurobryconin phylogeny and putative pheromone pumps in glandulocaudine fishes (Teleostei, Characidae)

Weitzman, Stanley H.; Fink, Sara V.

doi:10.5479/si.00810282.421

Cited by 113 publications

(152 citation statements)

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“…Brittanichthys axelrodi exhibit a unique combination of characters that has led to numerous discussions of relationship (e.g., Géry, 1965;Weitzman and Fink, 1985;Weitzman and Menezes, 1998;Malabarba and Weitzman, 1999), but at this time we hesitate to suggest what if any known genus is sister to Brittanichthys. It is clear from the above that B. axelrodi possesses characters that are similar to those of inseminating species from several lineages.…”

Section: Discussionmentioning

confidence: 99%

Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America

Javonillo

Burns

Weitzman

2006

Journal of Morphology

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Light and electron microscopy were used to investigate the morphology of reproductive characters in a characid fish, Brittanichthys axelrodi. Spermatozoa were found in ovaries of females, thereby confirming insemination in this species. Bony hooks can be found on the fourth unbranched ray and branched rays 1-4 of the anal fin and the unique sigmoidally-curved ray of the caudal fin in mature males. Testes have three distinct regions: an anterior spermatogenic region, an aspermatogenic middle region lined with a simple squamous epithelium and used for storage of mature spermatozoa, and a posterior region of coiled chambers lined with a high simple cuboidal epithelium. The most posterior region appears to be instrumental in the formation and storage of spermatozeugmata, unencapsulated sperm packets. Thus far, this tripartite testis morphology is unique among characids. The mature spermatozoon has an elongate nucleus ( 5 lm in length). A striated rootlet originates at the anterior end of the distal centriole and continues to the anterior tip of the cell. The striated rootlet wraps around the entire ventral area of the anterior part of the nucleus and appears to continue around the anterior tip of the nucleus and down the dorsal side as electron-dense material. Several large, spherical mitochondria ( 0.6 lm in diameter) with lamellar cristae overlap the posterior end of the nucleus and continue beyond together with the cytoplasmic collar that contains the flagellum which lacks axonemal fins. Each spermatozeugma is lanceolate in shape when sectioned mid-sagitally, with the core staining positively for mucopolysaccharides. In both sexes, the gonopore opens posterior to the anus, with the urinary pore having a separate opening posterior to the gonopore. Bands of skeletal muscle were found in the area of the male gonopore. These morphological features are likely linked to the reproductive mode of insemination, a trait that is so far as known, relatively rare among teleost fishes, but is proving increasingly frequent among certain groups of characid fishes.

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Section: Discussionmentioning

confidence: 99%

Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America

Javonillo

Burns

Weitzman

2006

Journal of Morphology

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“…The later addition of Chrysobrycon restricted the definition of the Xenurobryconini to the presence of a single pouch scale with or without hypertrophied radii in adult males, an ambiguously optimized character in the phylogenetic hypothesis by Weitzman & Menezes (1998), giving little support to the new composition of the group. With effect, the recent study by Thomaz et al (2015), questioned the monophyly of the Xenurobryconini, since their data strongly refuted Chrysobrycon (nested within the Stevardiini) and Argopleura (now an incertae sedis taxon) as members of the tribe, as previously proposed by Weitzman & Fink (1985), Weitzman et al (1994) and Weitzman & Menezes (1998).…”

Section: Introductionmentioning

confidence: 90%

“…The Xenurobryconini (Characidae: Stevardiinae) traditionally comprises seven inseminating genera (Weitzman & Fink, 1985;Weitzman & Menezes, 1998) Weitzman & Fink (1985), based on sexually dimorphic characters. Such phylogenetic definition was subsequently adjusted by Weitzman et al (1994) to include the genus Ptychocharax in the group, although any explicit phylogenetic hypothesis was provided.…”

Section: Introductionmentioning

confidence: 99%

A new miniature of Xenurobryconini (Characiformes: Characidae) from the rio Tapajós basin, Brazil

et al. 2016

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A new species of Xenurobrycon is described from tributaries of the rio Tapajós, Pará, Brazil. It is diagnosed from all congeners by the dark color of the posterior half of both caudal-fin lobes, the presence of infraorbitals one, two, and three, the presence of a set of lamellar processes on eighth principal caudal-fin ray of mature males, the presence of bony hooks similar in size or decreasing posteriorly on last unbranched and first 9-12 branched anal-fin rays of mature males, the presence of only conical teeth on both jaws, the lack of the adipose fin and the presence of 15-18 predorsal scales. The description of the new species increases the number of species in Xenurobrycon to six. An updated key to the species of the genus is provided.Uma espécie nova de Xenurobrycon é descrita de tributários do rio Tapajós, Pará, Brasil. Esta é diagnosticada de todas as congêneres pela coloração escura da metade posterior de ambos os lobos da nadadeira caudal, pela presença dos infraorbitais um, dois e três, pela presença de um conjunto de processos laminares no oitavo raio principal do lobo inferior da nadadeira caudal em machos maduros, pela presença de ganchos no último raio indiviso e primeiros 9-12 raios ramificados da nadadeira anal em machos maduros, estes com tamanho similar ou diminuindo de tamanho posteriormente, pela presença de apenas dentes cônicos nas maxilas, pela ausência de nadadeira adiposa e pela presença de 15-18 escamas pré-dorsais. A descrição da espécie nova aumenta o número de espécies em Xenurobrycon para seis. Uma chave atualizada para as espécies do gênero é fornecida.

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“…Although this procedure was in general effective for alpha taxonomy, it resulted in an artificial delimitation of many non-monophyletic groups of species. This is the case for the most diverse characid genera, such as Hemigrammus (54 species), Hyphessobrycon (130 species) and Moenkhausia (76 species) (Weitzman & Fink, 1983;Lima et al, 2003;Eschmeyer, 2013). According to this classification, which is still being used to classify species (e.g., Carvalho et al, 2010;Marinho, 2010;Sousa et al, 2010;Bertaco et al, 2011aBertaco et al, , 2011bIngenito et al, 2013), the genus Hemigrammus is diagnosed from Hyphessobrycon uniquely by the presence of small scales covering the proximal portion of the caudal-fin lobes (vs. absence), and from Moenkhausia by having an incompletely pored lateral line (vs. completely pored lateral line).…”

Section: Geographic Distributionmentioning

confidence: 99%

“…discussed in Eigenmann (1917)] and Odontostilbe dialeptura Fink & Weitzman, 1974. Lateral line reduction is hypothesized to have been independently acquired within several lineages in Characidae (Mirande, 2010), probably as a result of independent events of miniaturization, which may advance the presence of paedomorphic characters (Buckup 1998;Weitzman & Fink, 1983;Weitzman & Vari, 1988). Variation of lateral line perforation within a species may represent a key to understand mechanisms of truncation of the laterosensory canal system on body.…”

Section: Geographic Distributionmentioning

confidence: 99%

Hemigrammus ataktos: a new species from the rio Tocantins basin, central Brazil (Characiformes: Characidae)

2014

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A new species of Hemigrammus is described from the middle rio Tocantins basin, central Brazil. The new species can be distinguished from all congeners by having a black midlateral stripe on the body extending from the posterior margin of the eye to the median caudal-fin rays. Mature males possess dorsal-, pelvic-, and anal-fin rays elongate, features that also help to recognize the new species. Although the new species is described in Hemigrammus, some specimens present a complete series of pored scales in the lateral line. A discussion about the generic allocation of the new species is presented. Uma espécie nova de Hemigrammus é descrita da bacia do médio rio Tocantins, Brasil central. A espécie nova distingue-se de seus congêneres por apresentar uma faixa mediana negra na lateral do corpo desde a margem posterior do olho até os raios medianos da nadadeira caudal. Machos maduros apresentam os raios das nadadeiras dorsal, pélvica e anal alongados, características que também auxiliam o reconhecimento da espécie. Apesar da espécie nova ser descrita em Hemigrammus, alguns exemplares possuem série completa de escamas perfuradas na linha lateral. Uma discussão sobre o posicionamento genérico da espécie nova é apresentada.

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Xenurobryconin phylogeny and putative pheromone pumps in glandulocaudine fishes (Teleostei, Characidae)

Cited by 113 publications

References 0 publications

Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America

Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America

A new miniature of Xenurobryconini (Characiformes: Characidae) from the rio Tapajós basin, Brazil

Hemigrammus ataktos: a new species from the rio Tocantins basin, central Brazil (Characiformes: Characidae)

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