Mental gland

{{Short description|Body part in some animals that produces chemicals used for communation}} 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.<ref name=Turtle>{{cite journal|date=May 17, 2021|title=Evolutionary history of mental glands in turtles reveals a single origin in an aquatic ancestor and recurrent losses independent of macrohabitat|author1= Alejandro Ibáñez|author2= Uwe Fritz|author3= Markus Auer|author4= Albert Martínez-Silvestre|author5= Peter Praschag|author6= Emilia Załugowicz|author7= Dagmara Podkowa |author8= Maciej Pabijan |journal=Scientific Reports |volume= 11|issue=10396|page=10396 |doi=10.1038/s41598-021-89520-w |pmid=34001926 |pmc=8129087 |bibcode=2021NatSR..1110396I |s2cid=234770430 |type=Full text|doi-access=free}}</ref><ref name=Phylogeny>{{cite journal|title=Phylogeny of Mental Glands, Revisited|author1=David M. Sever|author2=Dustin S. Siegel|author3= Michael S. Taylor|author4= Christopher K. Beachy1|journal=Copeia|volume= 104|issue=1|pages=83–93|date=March 17, 2016|doi= 10.1643/CH-14-210|pmid=30034038 |pmc=6054469 |type=Full text}}</ref>

==Location==

The mental glands appear in pairs, one on each side of the head. They are located behind the end of the mandible.<ref name=Turtle /><ref name=Salamander />

==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.<ref name=Turtle /><ref name=Salamander>{{cite journal|journal=Acta Zoologica|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/azo.12158|accessdate=July 5, 2022|title=Ultrastructure of the mental gland of the Red-Backed Salamander, Plethodon cinereus (Amphibia: Plethodontidae) |author=David M. Sever |date=January 18, 2016 |volume=98 |issue=2 |pages=154–162 |doi=10.1111/azo.12158|type=Abstract|url-access=subscription}}</ref><ref name=Salamander2>{{cite journal|journal=Acta Zoologica|volume =98 |issue =2 |pages= 154–162|title=Histology of mental and caudal courtship glands in three genera of plethodontid salamanders (Amphibia: Plethodontidae) |author1=Ariana E. Rupp | author2=David M. Sever|accessdate=July 5, 2022|date=February 14, 2017|url=http://www2.southeastern.edu/Academics/Faculty/dsever/RuppSever2018.pdf|publisher=Royal Swedish Academy of Sciences|doi=10.1111/azo.12188|type=Full text}}</ref>

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.<ref name=Turtle /> 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.<ref name=Phylogeny />

==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.<ref name=Turtle /><ref name=Phylogeny />

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 tissue of homologous origin. They inferred that turtles that do not have mental glands lost them.<ref name=Turtle />

==References== {{reflist}} Category:Chemistry Category:Herpetology Category:Glands