amplexus

Orange-thighed Frogs (Litoria xanthomera) mating

Amplexus of European Common Toad (Bufo bufo)

The Amplexus of a common toad. The dotted strands are eggs produced during Amplexus

Amplexus (Latin "embrace") is a form of pseudocopulation in which a male amphibian grasps a female with his front legs as part of the mating process. At the same time or with some time delay, he fertilizes the female eggs with fluid containing sperm.

Amplexus chiefly occurs aquatically, but some more terrestrial anurans like the disc-tongued frogs (Discoglossidae) perform amplexus on land. In more advanced anurans like the true frogs (Ranidae), the tree frogs (Hylidae) and the true toads (Bufonidae) the amplexus is axillary (in the armpits), while in less derived anurans (the Archaeobatrachia) and frogs in the Myobatrachidae family it is lumbar (abdominal, in front of the hindlegs). The Sooglossidae show inguinal amplexus where the male holds the female at the waist just anterior to her hind legs. Some species show cephalic amplexus where the head of the female is held while others show complete lack of amplexus.

In most anurans the males deposit sperm onto the eggs as they are being laid, however males of the genus Ascaphus possess an intromittent organ, unique among anurans, for internal fertilization. Internal fertilization does occur in a few other genera, including Nectophrynoides, Mertensophryne, and Eleutherodactylus.^[1][2]

Newts

In the case of newts the process of amplexus is often observed soon after the newts become seasonally active. In the western USA, for example, this time is typically soon after the onset of the winter rainy season, when intermittent streams and seasonal ponds become available as breeding habitat. The Rough-skinned Newt is a specific widespread example of a newt in the western USA that can be observed in quiet stream pools and shallow ponds engaging in amplexus.^[3]

Media

• Amplexus in Action

See also

• nuptial pad

References

Wikimedia Commons has media related to: Amphibia sex