The common mudpuppy (Necturus maculosus) is a species of salamander in the family Proteidae. It is a nocturnal creature, and is active during the day only if the water in which it lives is murky. In contrast to axolotls, in mudpuppies, these THs are normally expressed. However, it is believed that instead of having TH-insensitive tissues that block the effects of THs, some mudpuppy tissues, such as the external gills, have lost the ability to be regulated by TH over time. This selective insensitivity to THs suggests a normal level of activity in the hypothalamo-pituitary-thyroid axis in developing mudpuppies, unlike other salamander species.

The common mudpuppy also does not have a parathyroid gland. The majority of salamanders with parathyroid glands rely on them to help with hypercalcemic regulation; hypercalcemic regulation in mudpuppies is primarily done by the pituitary gland instead.

Distribution

Common Mudpuppies have the largest distribution of any full aquatic salamander in North America. Necturus maculosus specimens live in streams, lakes, and ponds in the eastern part of North America. Populations are declining due to habitat degradation and chemical pollutants, such as PCBs and lampricides, from agricultural, industrial, and residential practices.

Diet

thumb|392x392px|A) Overall view of common mudpuppy mouth. B) Ventral view of vomerine and premaxillary teeth, located on the upper part of the mudpuppy mouth. C) Lower jaw, or dentary from a common mudpuppy showing the homodont dentary teeth. Specimen from the Pacific Lutheran University Natural History collection

Mudpuppies use rows of teeth to eat their prey. All the teeth, despite their different locations, are very similar. They are small and conical, meaning mudpuppies are homodonts due to their similar shape. The common mudpuppy never leaves its aquatic environment and therefore does not undergo morphogenesis; however, many salamanders do and develop differentiated teeth. Aquatic salamander teeth are used to hinder escape of the prey from the salamander; they do not have a crushing function. Their diet changes seasonally, with stomach contents of mudpuppies being only invertebrates in summer and fall, and fish being added in spring and winter. Their diet can also be affected by size and age of the salamander, with juveniles (under 20 cm) eating less fish and crayfish and more leeches and amphiopods than adults.

Further reading

  • Rafinesque CS (1818). "Further Account of Discoveries in Natural History, in the Western States". American Monthly Magazine and Critical Review 4: 39–42. (Sirena maculosa, new species, p. 41).
  • Mudpuppy (Necturus maculosus), Natural Resources Canada