Nuptial pad

A nuptial pad (or thumb pad, nuptial ball,^[1] nuptial excrescence^[2]) is a secondary sex characteristic present on some mature male frogs and salamanders.^[3][4][5][6] Triggered by androgen hormones, this breeding gland (a type of mucus gland) appears as a spiked epithelial swelling on the forearm and prepollex that aids with grip, used primarily by males to grasp (or clasp) females during amplexus.^[7] They can also be used in male-male combat in some species.^[7]

Male common frog in breeding colors with nuptial pad on first finger

Historical background

Austrian biologist Paul Kammerer experimented on midwife toads' nuptial pads.^[8] He used the offsprings' apparent enlargening from generation-to-generation as evidence of Lamarckian evolution.^[9]

Species examples

Many amphibian species manifest nuptial pads for use in amplexus, an example being the Rough-skinned newt, Taricha granulosa.^[10]

See also

• amplexus
• metatarsal knob
• spadefoot

Notes

1. ^ "Amphibian Species of the World". Research.amnh.org. 2009-04-30. http://research.amnh.org/herpetology/amphibia/references.php?id=16848. Retrieved 2011-07-14. 
2. ^ Lynch, J. D. and P. M. Ruiz-Carranza. (1996). "A remarkable new centrolenid frog from Colombia with a review of nuptial excrescences in the family". Herpetologica 52: 525–535. 
3. ^ "Science & Nature - Wildfacts - Common frog, grass frog". BBC. 2008-07-25. http://www.bbc.co.uk/nature/wildfacts/factfiles/483.shtml. Retrieved 2011-07-14. 
4. ^ "Mertensiella caucasica". AmphibiaWeb. 1999-10-03. http://amphibiaweb.org/cgi-bin/amphib_query?query_src=aw_search_index&table=amphib&special=one_record&where-genus=Mertensiella&where-species=caucasica. Retrieved 2011-07-14. 
5. ^ "Ommatotriton ophryticus". AmphibiaWeb. 2005-10-26. http://amphibiaweb.org/cgi-bin/amphib_query?query_src=aw_search_index&table=amphib&special=one_record&where-genus=Ommatotriton&where-species=ophryticus. Retrieved 2011-07-14. 
6. ^ "Pleurodeles waltl". AmphibiaWeb. 2002-05-25. http://amphibiaweb.org/cgi-bin/amphib_query?query_src=aw_search_index&table=amphib&special=one_record&where-genus=Pleurodeles&where-species=waltl. Retrieved 2011-07-14. 
7. ^ ^{a b} F. Harvey Pough ... (2004). Herpetology. Upper Saddle River, NJ: Pearson/Prentice Hall. pp. 67–8. ISBN 0131008498. 
8. ^ Koestler, Arthur (1971). The Case of the Midwife Toad. Random House. 
9. ^ [1]^{[dead link]}
10. ^ * C. Michael Hogan. 2008. Rough-skinned Newt (Taricha granulosa), Globaltwitcher, ed. Nicklas Stromberg [2]