Search results
Results from the WOW.Com Content Network
Ribs are generally absent, so the lungs are filled by buccal pumping and a frog deprived of its lungs can maintain its body functions without them. [69] The fully aquatic Bornean flat-headed frog (Barbourula kalimantanensis) is the first frog known to lack lungs entirely. [72] Frogs have three-chambered hearts, a feature they share with lizards.
For example, before the 2003 European heat wave that decimated populations of the water frog Rana lessonae through chytridiomycosis, the fungus existed on the amphibians as spherical, unicellular organisms, confined to minute patches (80-120 μm across). These organisms, unknown at the time, were subsequently identified as B. dendrobatidis.
[100] [101] Lungs and swim bladders are homologous (descended from a common ancestral form) as is the case for the pulmonary artery (which delivers de-oxygenated blood from the heart to the lungs) and the arteries that supply swim bladders. [102] Air was introduced into the lungs by a process known as buccal pumping. [103] [104]
Xenopus (/ ˈ z ɛ n ə p ə s / [1] [2]) (Gk., ξενος, xenos = strange, πους, pous = foot, commonly known as the clawed frog) is a genus of highly aquatic frogs native to sub-Saharan Africa. Twenty species are currently described within it.
The pulmonates have lost their gills [1] and adapted the mantle cavity into a pallial lung. The lung has a single opening on the right side, called the pneumostome, which either remains permanently open, or opens and closes as the animal breathes. The roof of the lung is highly vascularised, and it is through this surface that gas exchange occurs.
The skin of these animals is highly vascularized and moist, with moisture maintained via secretion of mucus from specialized cells. While the lungs are of primary importance to breathing control, the unique properties of cutaneous respiration supplements rapid gas exchange when amphibians are submerged in oxygen-rich water. [7]
A chytrid-killed frog Chytridiomycosis in Atelopus varius—two sporangia containing numerous zoospores are visible.. Chytridiomycosis (/ k aɪ ˌ t r ɪ d i ə m aɪ ˈ k oʊ s ɪ s / ky-TRID-ee-ə-my-KOH-sis) is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans.
They are distinguished in two respects: they were the earliest known jawed vertebrates, and they had stout spines supporting their fins, fixed in place and non-movable (like a shark's dorsal fin). The acanthodians' jaws are presumed to have evolved from the first gill arch of some ancestral jawless fishes that had a gill skeleton made of pieces ...