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| Oliveira,Cristina L. C. de; Malabarba,Luiz R.; Burns,John R.. |
| The structure and form of gill gland among inseminating and externally fertilizing species of the Cheirodontinae are described under light microscopy, scanning electron microscopy, and transmission electron microscopy, and compared to other members of the family Characidae. At least one species from thirteen cheirodontine genera were analyzed, totaling seventeen species. Gill glands were found in all analyzed mature males of Cheirodontinae and were always absent in females, being located on the anteriormost portion of the lower branch of the first gill arch, extending posteriorly through a variable number of gill filaments. Gill glands of all cheirodontines and of all characid species in which this organ has been described possess the same structure, being... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Characid clade A; Characid clade B; Gill filaments; Gill secondary lamellae. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252012000200010 |
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| Pecio,Anna; Burns,John R.; Weitzman,Stanley H.. |
| Spermiogenesis and sperm ultrastructure were analyzed in two species of characids with different modes of fertilization: externally fertilizing Hemigrammus erythrozonus and inseminating Corynopoma riisei. Spermiogenesis in H. erythrozonus is characterized by lateral development of the flagellum, nuclear rotation, formation of a shallow nuclear fossa, condensation of the chromatin by elimination of the electron-lucent area from the peripheral region of the nucleus, and renewal of the nuclear membrane. Multilammelated membrane and multivesicular bodies were also observed during elimination of the excess cytoplasm. The spermatozoon exhibits characters typical of "aquasperm," i.e. a spherical head containing a spherical nucleus with highly condensed chromatin,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nuclear rotation; Aquasperm; Introsperm; Characids. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252007000400005 |
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| Weitzman,Stanley H.; Menezes,Naércio A.; Evers,Hans-Georg; Burns,John R.. |
| A new inseminating fish species of the family Characidae, Bryconadenos tanaothoros, from tributaries of the upper rio Xingu and upper rio Tapajós basins, Mato Grosso, Brazil is described as the type species of a new genus. This new species and the genus are characterized by a glandular organ on the anterior region of the anal fin of sexually mature males, curved lower jaw teeth, and an inseminating reproductive mode. This new genus is hypothesized as most closely related to Attonitus, a genus with three inseminating species from Peru. Bryconadenos and Attonitus are suggested as related to certain inseminating, but undescribed characid species of uncertain relationships that are similar in certain respects to species of the glandulocaudine Planaltina and to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Inseminating characid phylogeny; Putative male pheromone cells; Attonitus; Bryconadenos; Knodus. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000300002 |
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| Giora,Júlia; Burns,John R.. |
| This study presents details of sperm ultrastructure for Gymnotus aff. carapo (Gymnotidae), Eigenmannia trilineata (Sternopygidae), and three Brachyhypopomus species (B. draco, B. bombilla, and B. gauderio - Hypopomidae) from southern Brazil. Differences were found among the representatives of the different families. For example, nuclear rotation was present in E. trilineata and in the Brachyhypopomus species, but absent in Gymnotus aff. carapo, and the presence of flagellar fins was only observed in E. trilineata. Some intraspecific variations could also be noticed among the Brachyhypopomus species analyzed. Most of the characters found in the spermatozoa of the species studied herein are shared with species of Gymnotiformes previously analyzed. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gymnotidae; Hypopomidae; Spermatozoa; Sternopygidae. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252011000400019 |
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