![NuptialPad](https://upload.wikimedia.org/wikipedia/commons/0/0b/NuptialPad.jpg)
A nuptial pad (also known as thumb pad, or nuptial excrescence) is a
secondary sex characteristic
Secondary sex characteristics are features that appear during puberty in humans, and at sexual maturity in other animals. These characteristics are particularly evident in the sexually dimorphic phenotypic traits that distinguish the sexes of a s ...
present on some mature male
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s and
salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
s. Triggered by
androgen
An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...
hormones, this
breeding gland (a type of
mucous gland
Mucous gland, also known as muciparous glands, are found in several different parts of the body, and they typically stain lighter than serous glands during standard histological preparation. Most are multicellular, but goblet cells are single-cel ...
) appears as a spiked
epithelial
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercell ...
swelling on the
forearm
The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...
and
prepollex that aids with grip, which is used primarily by males to grasp (or clasp) females during
amplexus
Amplexus (Latin "embrace") is a type of mating behavior exhibited by some externally fertilizing species (chiefly amphibians and horseshoe crabs) in which a male grasps a female with his front legs as part of the mating process, and at the same ...
.
They can also be used in male–male combat in some species.
Historical background
Austrian biologist
Paul Kammerer
Paul Kammerer (17 August 1880, in Vienna – 23 September 1926, in Puchberg am Schneeberg) was an Austrian biologist who studied and advocated Lamarckism, the theory that organisms may pass to their offspring characteristics acquired in their lif ...
experimented on
midwife toad
Midwife toads are a genus (''Alytes'') of frogs in the family Alytidae (formerly Discoglossidae), and are found in most of Europe and northwestern Africa. Characteristic of these toad-like frogs is their parental care; the males carry a string o ...
s' nuptial pads. He used the offspring's apparent enlargening from generation-to-generation as evidence of
Lamarckian evolution
Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also calle ...
.
Examples
Many
amphibian species manifest nuptial pads for use in amplexus, an example being the
rough-skinned newt
The rough-skinned newt or roughskin newt (''Taricha granulosa'') is a North American newt known for the strong toxin exuded from its skin.
Appearance
A stocky newt with rounded snout, it ranges from light brown to olive or brownish-black on ...
, ''Taricha granulosa''.
See also
*
*
References
{{reflist, 30em
Amphibian anatomy
Mating
Sexual anatomy