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A hindlimb or back limb is one of the paired articulated appendages attached on the caudal end of a terrestrial tetrapod vertebrate's torso. [1] With reference to quadrupeds, the term hindleg or back leg is often used instead. In bipedal animals with an upright posture (e.g. humans and some primates), the term lower limb is often used.
The hind limbs are short, and the tibiotarsal articulation reaches the axilla or the tympanum. The skin above is smooth or granulate, with some scattered tubercles or short, interrupted longitudinal folds; a strong fold runs from the eye to the shoulder; the belly and lower surfaces of thighs are granulate.
The numbers of species cited above follows Frost and the total number of known (living) amphibian species as of March 31, 2019, is exactly 8,000, [12] of which nearly 90% are frogs. [ 13 ] With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart ...
Snakes are a particularly good example for studying limb loss, as they underwent limb loss and regeneration multiple times throughout their evolution before they finally lost their legs for good. Much of the gene expression during embryonic development is regulated via spatiotemporal and chemotactic signaling, [20] as depicted by the image to ...
Many representative terrestrial vertebrates possess a distal cushion on the under-surface of the foot. The dog's paw contains a number of visco-elastic pads oriented along the middle and distal foot. The horse possesses a centralized digital pad known as the frog, which is located at the distal aspect of the foot and surrounded by the hoof. [12]
By Keith Morrison Taking the phrase of "putting it under the microscope" quite literally, the Nikon Small World contest recently announced its winners for 2014. Now in its 40th year, the contest ...
This hypothesis comes in a number of variants, most of which have lissamphibians coming out of the dissorophoid temnospondyls, usually with the focus on amphibamids and branchiosaurids. [ 74 ] The temnospondyl hypothesis is the currently favored or majority view, supported by Ruta et al (2003a,b), Ruta and Coates (2007), Coates et al (2008 ...
The characteristics of anuran adults include: 9 or fewer presacral vertebrae, the presence of a urostyle formed of fused vertebrae, no tail, a long and forward-sloping ilium, shorter fore limbs than hind limbs, radius and ulna fused, tibia and fibula fused, elongated ankle bones, absence of a prefrontal bone, presence of a hyoid plate, a lower ...