The buccal morphology was compared between the sexes of the cardinalfish Apogon doederleini, in which males provide mouthbrooding. The brood size increased proportionally with male buccal space, which increased with the fourth power of the standard length. In the breeding season, males had a larger buccal space than females, whereas there was no sexual difference in the non-breeding season, sug...

From comparisons of the cephalic and pectoral girdle structures of Plotosus lineatus with those of other plotosid as well as non-plotosid siluriforms, plotosid catfishes can be defined by at least six autapomorphies. These are: (1) the absence of the ventral division of the muscle arrector dorsalis; (2) the double articulation between the neurocranium and the anterior part of the suspensorium; ...

The muscles of the cephalic region and pectoral girdle of Arius heudeloti, Genidens genidens andBagre marinus are described and compared with those of non-ariid siluriforms. Our observations and compar-isons revealed that, although the configuration of the cephalic and pectoral girdle musculature of these ariidspecies is basically similar to that of other catfishes, these species pr...

The cephalic and pectoral girdle structures of the South African catfish Austroglanis gilli are described and compared with those of other catfishes, either studied by us or described in the literature, as the foundation for a discussion on Austroglanididae autapomorphies, and also on the phylogenetic relationships between the austroglanidids and the other catfishes. Our observations, compariso...

We analyzed the functional morphology and evolution of the long jaws found in several butterflyfishes. We used a conservative reanalysis of an existing morphological dataset to generate a phylogeny that guided our selection of seven short- and long-jawed taxa in which to investigate the functional anatomy of the head and jaws: Chaetodon xanthurus, Prognathodes falcifer (formerly Chaetodon falci...

Lysorophians are a group of early tetrapods with extremely elongate trunks, reduced limbs, and highly reduced skulls. Since the first discovery of this group, general similarities in outward appearance between lysorophians and some modern lissamphibian orders (specifically Urodela and Gymnophiona) have been recognized, and sometimes been the basis for hypotheses of lissamphibian origins. We stu...

It is generally assumed that biting performance trades off with suction performance in fish because both feeding types may place conflicting demands on the cranial musculo-skeletal system. However, the functional consequences of morphological adaptations enhancing biting on the mechanics and performance of suction feeding in fish remain obscure. In this study, suction feeding performance was co...

Here we document sexual dimorphism in both external measurements of the head and discrete features of the skull in Apteronotus bonapartii. To quantify morphological variation in A. bonapartii, ten external morphometric measurements were taken from the head and body of 58 individuals. By using Discriminant Function Analysis, we found that the best predictors for distinguishing sexes are the body...

Cranial skeletal morphology, ontogeny and variation are examined in five species of Thorim, a genus of diminutive plethodontid salamanders that are among the smallest, extant, tailed tetrapods. The akull of adult 'Thhoriu~ is characterized by: (1) limited development or absence of several ossified clemrnts and dentition; (2) increased interand intraspecifir variability; (3) novel morphological ...

Despite the importance of rabbits in reproductive studies, little information is available on the anatomy and participation of the striated-perineal muscles in male copulatory behavior. In our study, we describe the gross anatomy of two striated-perineal muscles: the ischiocavernosus (ICm) and the bulbospongiosus (BSm). Both muscles have their origin at the ischiadic arc, but the ICm is inserte...