Fishes are known to have a great deal of variability in their vertebrae especially near the occipital region. Despite this observed variability, there is new and compelling evidence for developmental conservatism in the region for actinopterygians (Bemis & Forey 2001; Britz & Johnson 2010; Johnson & Britz 2010). Authors have even hypothesized that the occiput could be homologous among chondrich...

The acute effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure have been well documented in many vertebrate species. However, less is known about the consequences in adulthood from sublethal exposure during development. To address this, we exposed zebrafish to sublethal levels of TCDD (1h; 50 pg/ml), either in early embryogenesis (day 0) or during sexual determination (3 and 7 weeks),...

The debate about the origin of the vertebrate dentition has been given fresh fuel by new fossil discoveries and developmental studies of extant animals. Odontodes (teeth or tooth-like structures) can be found in two distinct regions, the 'internal' oropharyngeal cavity and the 'external' skin. A recent hypothesis argues that regularly patterned odontodes is a specific oropharyngeal feature, whe...

Wetting and drying cycles are widely recognised as driving aquatic macroinvertebrate zooplankton production, providing prey recruitment opportunities for fish in floodplain river systems. Conversely, invertebrate consumption of fishes features less frequently food web studies. We used two sources information: a) the finding an intact eel skeleton exceedingly high number diving beetles (Cybister...

The shapes of vertebrate teeth are often used as hallmarks of diet. Here, however, we demonstrate evidence of frequent piscivory by cartilaginous fishes with pebble-like teeth that are typically associated with durophagy, the eating of hard-shelled prey. High-resolution micro-computed tomography observation of a jaw specimen from one batoid species and visual investigation of those of two addit...

Animal propulsion systems are believed to show high energy and mechanical efficiency in assisting movement compared to artificial designs. As an example, batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming via enlarged wing-like pectoral fins. The aim of this work is to illustrate the hierarchical structure of the pectoral fin of a representative batoid,...

The synarcual is a structure incorporating multiple elements of two or more anterior vertebrae of the axial skeleton, forming immediately posterior to the cranium. It has been convergently acquired in the fossil group 'Placodermi', in Chondrichthyes (Holocephali, Batoidea), within the teleost group Syngnathiformes, and to varying degrees in a range of mammalian taxa. In addition, cervical verte...

Melorheostosis is a rare sclerosing hyperostosis that affects the appendicular skeleton more than the axial skeleton. This disorder also affects the cutaneous and soft tissues and leads to the formation of fibrosis and contracture. Due to the unique features of melorheostosis (dripping candle wax appearance), plain radiographs are often sufficient for diagnosis. Herein we report a case of melor...

The fossils assigned to the tetrapod stem group document the evolution of terrestrial vertebrates from lobe-finned fishes. During the past 15 years the phylogenetic structure of this stem group has remained remarkably stable, even when accommodating major new discoveries such as the elpistostegid Tiktaalik. Here we present a large tetrapodomorph fish from the Late Devonian of China that disrupt...