Mental gland

A mental gland is a part of the body found in many species of amphibians and reptiles. Mental glands produce chemicals that conspecific animals use to communicate.[1][2]

Location

The mental glands appear in pairs, one on each side of the head. They are located behind the end of the mandible.[1][3]

Function

Mental glands produce hormones that are secreted through the skin. The secretions from mental glands have been implicated in mate selection, species identification, and other functions.[1][3][4]

Scientists believe that the head bobbing behavior observed in turtles encountering another member of their own species may serve to disperse the chemicals from the mental glands through the air.[1] Certain courtship behaviors observed in salamanders, such as snapping, only appear in salamanders that have mental glands, so scientists believe they are also meant to spread the chemicals through the air.[2]

Origins and evolution

Not all reptiles and amphibians have mental glands. It is not unusual for some species in the same family to have mental glands while others do not.[1][2]

In 2021, one team of scientists found that most turtles that have mental glands are aquatic. They concluded that mental glands developed once in turtles, in the ancestor of the family Testudinoidea, and that all turtles that have mental glands develop them from homologous origin tissue. They inferred that turtles that do not have mental glands lost them.[1]

References
  1. Alejandro Ibáñez; Uwe Fritz; Markus Auer; Albert Martínez-Silvestre; Peter Praschag; Emilia Załugowicz; Dagmara Podkowa; Maciej Pabijan (May 17, 2021). "Evolutionary history of mental glands in turtles reveals a single origin in an aquatic ancestor and recurrent losses independent of macrohabitat". Scientific Reports (Full text). 11 (10396): 10396. Bibcode:2021NatSR..1110396I. doi:10.1038/s41598-021-89520-w. PMC 8129087. PMID 34001926. S2CID 234770430.
  2. David M. Sever; Dustin S. Siegel; Michael S. Taylor; Christopher K. Beachy1 (March 17, 2016). "Phylogeny of Mental Glands, Revisited". Copeia (Full text). 104 (1): 83–93. doi:10.1643/CH-14-210. PMC 6054469. PMID 30034038.
  3. David M. Sever (January 18, 2016). "Ultrastructure of the mental gland of the Red-Backed Salamander, Plethodon cinereus (Amphibia: Plethodontidae)". Acta Zoologica (Abstract). 98 (2): 154–162. doi:10.1111/azo.12158. Retrieved July 5, 2022.
  4. Ariana E. Rupp; David M. Sever (February 14, 2017). "Histology of mental and caudal courtship glands in three genera of plethodontid salamanders (Amphibia: Plethodontidae)" (PDF). Acta Zoologica (Full text). Royal Swedish Academy of Sciences. 98 (2): 154–162. doi:10.1111/azo.12188. Retrieved July 5, 2022.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.