Comparative morphology of gill glands in externally fertilizing and inseminating species of cheirodontine fishes, with implications on the phylogeny of the family Characidae (Actinopterygii: Characiformes)

Cristina L C De Oliveira,John R Burns,Luiz R Malabarba

doi:10.1590/s1679-62252012005000005

Cristina L C De Oliveira, John R Burns + Show 1 more

Open Access

https://doi.org/10.1590/s1679-62252012005000005

Copy DOI

Abstract

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 considered homologous and supporting a single origin of the structure in a common ancestor to Clade A and Clade B characids.

Highlights

The subfamily Cheirodontinae consists of 16 genera and approximately 54 species (Malabarba, 2003; Bührnheim et al, 2008), currently arranged into two tribes, Compsurini, and Cheirodontini, in addition to five genera of uncertain phylogenetic position within the subfamily (Aphyocheirodon, Cheirodontops, Odontostilbe, Prodontocharax, and Pseudocheirodon).Species within Cheirodontini and the incertae sedis genera are all externally fertilizing, whereas those within Compsurini are all inseminating, as observed by the presence of spermatozoa in their ovaries (Burns et al, 1997; Malabarba, 1998)
Gill glands were found in all analyzed mature males of the Cheirodontinae (Figs. 1 and 2) and were always absent in females
The development of gill glands begins with the multiplication of epithelial cells that will form a lateral cover over the anteriormost portion of the lower branch of the first gill arch

Summary

Introduction

The subfamily Cheirodontinae consists of 16 genera and approximately 54 species (Malabarba, 2003; Bührnheim et al, 2008), currently arranged into two tribes, Compsurini (including the genera Acinocheirodon, Compsura, Kolpotocheirodon, Macropsobrycon, and Saccoderma), and Cheirodontini (including the genera Amazonspinther, Cheirodon, Heterocheirodon, Nanocheirodon, Serrapinnus, and Spintherobolus), in addition to five genera of uncertain phylogenetic position within the subfamily (Aphyocheirodon, Cheirodontops, Odontostilbe, Prodontocharax, and Pseudocheirodon).Species within Cheirodontini and the incertae sedis genera are all externally fertilizing, whereas those within Compsurini are all inseminating, as observed by the presence of spermatozoa in their ovaries (Burns et al, 1997; Malabarba, 1998). Inseminating male characids often have hypertrophied tissues, that appear to be glandular, at discrete sites on the body Such tissues have been described on the caudal fin of the compsurin cheirodontines Acinocheirodon melanogramma (see Malabarba & Weitzman, 1999), Kolpotocheirodon theloura and Kolpotocheirodon figueiredoi (see Malabarba & Weitzman, 2000; Malabarba et al, 2004) and on the caudal fin of glandulocaudines and stevardiines (see Weitzman et al, 2005; Menezes & Weitzman, 2009). The fact that these hypertrophied tissues are restricted to mature males has been used to suggest that some components of the gland secretions may be used as chemical signals, perhaps even pheromones, for communication between males or between the sexes, possibly related to courtship and insemination (Kutaygil, 1959; Nelson, 1964; Weitzman & Fink, 1985)

Objectives

Methods

Results

Conclusion