Biting is an integral feature of the feeding mechanism for aquatic and terrestrial salamanders to capture, fix or immobilize elusive struggling prey. However, little information available on how it works functional implications this biting system in amphibians although such approaches might be essential understand systems performed by early tetrapods. Herein, skull biomechanics Chinese giant salamander, Andrias davidianus investigated using 3D finite element analysis. The results reveal that...

During the evolutionary transition from fish to tetrapods, a shift uni- bidirectional suction feeding systems followed reduction in gill apparatus. Such can still be observed during metamorphosis of salamanders, although many adult salamanders retain their aquatic lifestyle and feed by high-performance suction. Unfortunately, little is known about interplay between jaws hyobranchial motions generate flows. Here, we study cranial morphology, as well kinematic hydrodynamic aspects related prey...

To capture and swallow food on land, a sticky tongue supported by the hyoid gill arch skeleton has evolved in land vertebrates from aquatic ancestors that used mouth-cavity-expanding actions of to suck into mouth. However, evolutionary pathway bridging this drastic shift feeding mechanism associated motions remains unknown. Modern fish feed may help unravel physical constraints biomechanical solutions led terrestrialization fish-feeding systems. Here, we show mudskipper emerges onto with its...

It is generally accepted that most non-mammal tetrapods have a hinge-like jaw operation restricted to vertical opening and closing movements. Many mammal joints, by contrast, operate in more complex, three-dimensional ways, involving not only vertical, but also propalinal (rostro-caudal) transverse (lateral) Data on intraoral food processing lissamphibians sauropsids has prompted view these groups mostly swallow unreduced, those cases where chew, they use simple movements for processing. The...

The Spanish ribbed newt Pleurodeles waltl shows a bizzare defensive mechanism against predators. X-ray analysis before and after simulated threat that this rotates its ribs anteriorly. maximum measured angle to which the moved was 65°. This forward movement causes sharply pointed rib tips lacerate body wall project freely from sides of trunk as spines. Light microscopy microanatomy, computed tomography 3D morphology these unusual weapons. They are 'spear-shaped' hollow proximally, massive...

Almost all extant testudinids are highly associated with terrestrial habitats and the few tortoises high affinity to aquatic environments found within genus Manouria. Manouria belongs a clade which forms sister taxon remaining is suitable as model for studying evolutionary transitions modern turtles. We analysed feeding behaviour of emys due its phylogenetic position, we hypothesise that species might have retained some ancestral features an lifestyle. tested whether M. able feed both in...

Transitions between aquatic and terrestrial environments are significant steps in vertebrate evolution. These transitions require major changes many biological functions, including food uptake transport. The Alpine newt, Ichthyosaura alpestris, is known to show a 'multiphasic lifestyle' where the adult shifts from an lifestyle then back every year as result of its breeding activity. correspond dramatic morphology, physiology behavior, resulting distinct morphotypes. We hypothesized that...

Background The Weberian apparatus of otophysine fishes facilitates sound transmission from the swimbladder to inner ear increase hearing sensitivity. It has been great interest biologists since 19th century. No studies, however, are available on development ossicles and its effect in catfishes. Methodology/Principal Findings We investigated auditory sensitivity catfish Lophiobagrus cyclurus. Specimens 11.3 mm 85.5 standard length were studied. Morphology was assessed using sectioning,...

Abstract Some newt species change seasonally between an aquatic and a terrestrial life as adults, are therefore repeatedly faced with different physical circumstances that affect wide range of functions the organism. For example, it has been observed habitat‐changing newts display notable changes in skin texture tail fin anatomy, allowing one to distinguish morphotype. One main functional challenges is switch efficient prey capture modes. Recent studies have shown adapt quickly by showing...

Abstract Scanning Electron Microscopy (SEM) revealed that the palate of Cuora amboinensis has a flat surface with keratinized and non‐keratinized regions. Keratinization is reflected in disc‐shaped dead cells rough microplicae on surface, concentrated close to rhamphotheca. The hexagonal epithelial dotted microvilli sometimes cilia. Taste buds are present both lightly regions exhibit crater‐like shape. Light microscopy shows different tissue layers oral mucosa structures. In regions,...

Abstract Histological and ultrastructural investigations revealed three different multicellular skin gland types in the salamandrid Pleurodeles waltl . The mucous glands are small, with one layer of secretory cells surrounding a central lumen; they produce viscous slippery mucus film that has various functions amphibians. serous can be divided based on their histological characters into granular Type I (GGI) II (GGII). first type is moderately sized distributed throughout body surface,...

Transitions between aquatic and terrestrial habitats are significant steps in vertebrate evolution. Due to the different biophysical demands on whole organism water air, such transitions require major changes of many physiological functions, including feeding. Accordingly, capability modulate pre-programmed chain prey-capture movements might be essential maintain performance a new environment. Newts special interest this regard as they show multiphasic lifestyle where adults change...

Abstract A unique example of phenotypic flexibility the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps skin their upper lower jaws, labial lobes, to partly close corners mouth when they adopt lifestyle during breeding season. Using hydrodynamic simulations based on μCT-scans cranial kinematics prey-capture smooth newt ( Lissotriton vulgaris ), we showed this adaptive solution improve feeding...

Food processing refers to any form of food mechanical breakdown prior swallowing. Variations this behaviour are found within all major gnathostome groups. Chewing is by far the most commonly used intraoral mechanism and involves rhythmic mandibular jaw hyobranchial (tongue) movements. occurs in chondrichthyans (sharks rays), actinopterygians (ray-finned fishes), dipnoi (lungfishes) as well amniotes similarities patterns muscle activity movement feeding apparatus. It has been suggested that...

Abstract In tetrapods, the oropharyngeal cavity and its anatomical structures are mainly, but not exclusively, responsible for uptake intraoral transport of food. this study, we provide structural evidence a second function oropharynx in North American common musk turtle, Sternotherus odoratus , Kinosternidae: aquatic gas exchange. Using high‐speed video, demonstrate that S. can grasp food on land by jaws, is afterward incapable lingual based transport; always lost during such an attempt....

The oropharynx as a functional entity plays fundamental role in feeding. Transitions from aquatic to terrestrial lifestyles vertebrates demanded major changes of the for required adaptations different feeding environment. Extant turtles evolved modes three families (testudinids, emydids, geoemydids)–independently other amniotes–and are therefore important model organisms reconstruct morpho-functional behind aquatic-terrestrial transitions. In this study we hypothesized that oropharyngeal...

The present study examined the kinematic patterns of initial food uptake, transport, pharyngeal packing and swallowing in common musk turtle Sternotherus odoratus . These data are supplemented by morphological descriptions skull hyolingual complex. Although hyoid is mainly cartilaginous, S still use exclusively hydrodynamic mechanisms prey capture transport. tongue relatively small, with weakly developed intrinsic musculature. We propose that elasticity hypoglossum body impacts capability to...

Abstract In tetrapods, the ability to ingest food on land is based certain morphological features of oropharynx in general and feeding apparatus particular. Recent paleoecological studies imply that terrestrial has evolved secondarily turtles, so they had meet oropharyngeal requirements independently other amniotes. This study designed improve our limited knowledge about morphology tortoises by analyzing detail Manouria emys . Special emphasis placed form function tongue. Even if considered...