Background: The present study compared lethal concentrations (LC50-96 h) of CdCl2, CrCl3, and Pb (NO3)2 between two scaled and scaleless freshwater fish species: Cyprinus carpio (Cyprinidae) and Pangasius hypophthalmus (Pangasiidae). Methods: The experimental fishes were obtained from fish markets/ponds with average lengths and weights of approximately 11.68 ±1.92 and 9.8±1.9 cm, and 25.92±6....

Odontogenesis has only been closely scrutinized at the molecular level in the mouse, an animal with an extremely restricted dentition of only two types and one set. However, within osteichthyans many species display complex and extensive dentitions, which questions the extent to which information from the mouse is applicable to all osteichthyans. We present novel comparative molecular and morph...

In the present research, modification of the zona radiata (ZR) around the molly (Poecilia sphenops, Valencinnes 1846) and bighead carp (Hypophthalmichthys nobilis, Richardson 1845) oocytes and in the zygotes were studied for pre- and post-fertilization stages and its relationship with the reproductive strategy. Light and scanning electron microscopic studies on the histological sections of...

Adaptive phenotypic plasticity, the ability of an organism to change its phenotype to match local environments, is increasingly recognized for its contribution to evolution. However, few empirical studies have explored the molecular basis of plastic traits. The East African cichlid fish Astatoreochromis alluaudi displays adaptive phenotypic plasticity in its pharyngeal jaw apparatus, a structur...

Ray-finned fishes (Actinopterygii) are the dominant vertebrate group today (+30 000 species, predominantly teleosts), with great morphological diversity, including their dentitions. How dental morphological variation evolved is best addressed by considering a range of taxa across actinopterygian phylogeny; here we examine the dentition of Polyodon spathula (American paddlefish), assigned to the...

Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Muc...

—We sampled larval fish in 1999 and 2001 on a restored floodplain along the lower Cosumnes River, California, from the onset of flooding to when the sites dried or when larval fish became rare. We collected more than 13,000 fish, of which prickly sculpin Cottus asper made up the majority (73%). Eleven species made up 99% of the catch. Three native fishes (prickly sculpin, Sacramento sucker Cato...