Nuptial pad

A nuptial pad (also known as thumb pad, or nuptial excrescence^[1]) is a secondary sex characteristic present on some mature male frogs and salamanders.^[2][3][4][5] Triggered by androgen hormones, this breeding gland (a type of mucous gland) appears as a spiked epithelial swelling on the forearm and prepollex that aids with grip, which is used primarily by males to grasp (or clasp) females during amplexus.^[6] They can also be used in male–male combat in some species.^[6]

Nuptial pad (arrow) on thumb of Pelophylax esculentus

Historical background

Austrian biologist Paul Kammerer experimented on midwife toads' nuptial pads.^[7] He used the offspring's apparent enlargening from generation-to-generation as evidence of Lamarckian evolution.^[8]

Examples

Many amphibian species manifest nuptial pads for use in amplexus, an example being the rough-skinned newt, Taricha granulosa.^[9]

See also

• Amplexus – Type of mating behavior exhibited by some externally fertilizing species
• Humeral spine

References

1. William E. Duellman; et al. (1994). Biology of Amphibians. JHU Press. p. 55. ISBN 978-0-8018-4780-6.
2. "Science & Nature – Wildfacts – Common frog, grass frog". BBC. 2008-07-25. Retrieved 2011-07-14.
3. "Mertensiella caucasica". AmphibiaWeb. 1999-10-03. Retrieved 2011-07-14.
4. "Ommatotriton ophryticus". AmphibiaWeb. 2005-10-26. Retrieved 2011-07-14.
5. "Pleurodeles waltl". AmphibiaWeb. 2002-05-25. Retrieved 2011-07-14.
6. F. Harvey Pough; Andrews RM; Cadle JE; Crump ML; Savitsky AH; Wells KD (2004). Herpetology (3rd ed.). Upper Saddle River, NJ: Pearson/Prentice Hall. pp. 67–68. ISBN 0-13-100849-8.
7. Koestler, Arthur (1971). The Case of the Midwife Toad. Random House.
8. [1] September 17, 2008, at the Wayback Machine
9. C. Michael Hogan (2008). . Globaltwitcher, ed. Nicklas Stromberg. Archived from the original on 2009-05-27.