Search results
Results from the WOW.Com Content Network
Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip.
The tall neural spines of a bison form a hump rather than a sail.. The structure may also have been more hump-like than sail-like, as noted by Stromer in 1915 ("one might rather think of the existence of a large hump of fat [German: Fettbuckel], to which the [neural spines] gave internal support") [4] and by Jack Bowman Bailey in 1997. [5]
Class Amphibia (amphibians, some ancestral to the amniotes)—now a paraphyletic group; Class Synapsida (mammals and their extinct relatives) Class Sauropsida (reptiles and birds) While this traditional taxonomy is orderly, most of the groups are paraphyletic, meaning that the structure does not accurately reflect the natural evolved grouping. [47]
Amphibamus is a genus of amphibamid temnospondyl amphibians from the Carboniferous (middle Pennsylvanian) of North America. [1] [2] [3] This animal is considered to have been close to the ancestry of modern amphibians. Its length was about 20 centimetres (7.9 in). [4]
Although this site was named for the fossil, only a few neural spines and a rib bone were discovered. [3] The best cranial specimen was found by David Baldwin near Rio Puerco, New Mexico in 1881. The presence of a fragmented neural spine on the skull’s ventral surface indicated that it did indeed belong to a Platyhystrix specimen. [2]
A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a bilaterian animal belonging to the phylum Chordata (/ k ɔːr ˈ d eɪ t ə / kor-DAY-tə).All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa.
Generally, males have been found to possess larger bodies and longer heads compared to the female sex, which normally is indicative of male-male combat observed within the population. [21] [22] There has been, however, no other physical indicating factors for male-male combat as in other species of amphibians, such as horns or spines. [22]
The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by prehistoric temnospondyls such as Mastodonsaurus which could reach up to 6 m (20 ft) in length. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.