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Another Early Jurassic frog is Vieraella herbsti, which is known only from dorsal and ventral impressions of a single animal and was estimated to be 33 mm (1 + 1 ⁄ 4 in) from snout to vent. Notobatrachus degiustoi from the middle Jurassic is slightly younger, about 155–170 million years old.
(A) Dorsal view. (B) Lateral view. (C) Ventral view. (D) Mouth structure. [1] Gosner stage is a generalized system of describing stages of embryonal and larval development in anurans (frogs and toads). The Gosner system includes 46 numbered stages, from fertilized embryo (stage 1) to the completion of metamorphosis (stage 46).
During mating, the femoral glands' placement on the male's ventral surface of the thigh suggests that they may contact the female's dorsal skin, implicating the glands in reproductive signalling. [7] Gland secretions may influence female behaviour, potentially stimulating oviposition and aiding intra-species recognition . [ 8 ]
The frog is a part of a horse hoof, located on the underside, which should touch the ground if the horse is standing on soft footing. The frog is triangular in shape, and extends midway from the heels toward the toe, covering around 25% of the bottom of the hoof.
The hypaxial muscles are located on the ventral side of the body, often below the horizontal septum in many species (primarily fish and amphibians). In all species, the hypaxial muscles are innervated by the ventral ramus (branch) of the spinal nerves, while the epaxial muscles are innervated by the dorsal ramus. [citation needed]
The hairy frog is also notable in possessing retractable "claws", which it may project through the skin, apparently by intentionally breaking the bones of the toe. [5] These are not true claws, as they are made of bone, not keratin. In addition, there is a small bony nodule nestled in the tissue just beyond the frog's fingertip.
Character evolution seems to be complex, with multiple gains and/or losses of humeral spines, reduced hand webbing, and complete ventral transparency. Researched by Santiago (2009), [ 3 ] evolution and speciation on glass frogs has shown that ecological gradient and isolation have a role in speciation and divergence in glass frogs by comparing ...
Notochord is positioned just ventral to the neural tube and dorsal to the gut, flanked by myotome. (D) Notochord homolog in annelid. Cross-section showing the position of the proposed axochord to the ventral mesentery, blood vessel, and nerve chord. Axochord is found to be dorsal to the nerve chord and ventral to gut of the animal.