Fig 1: Wood-colored Webfoot Salamander (Blitoglossa lignicolor)
During our visit to Costa Rica, we had an incredible opportunity to go on a night hike with Raby, a Costa Rican naturalist, photographer and tour guide (@sierpe_frogs) in Uvita, Costa Rica. Although he helped us find many species of amphibians (and insects and lizards!), my favorite by far was this extraordinary Wood-colored Webfoot Salamander.
Belonging to the family of Lungless salamanders (Plethodontidae), Webfoot salamanders engage in cutaneous respiration and have short, tentacle-like structures below their nostrils called nasolabial protuberances. This structure has grooves which carry chemical cues from the environment to sensory organs located in the nostrils. Chemoreception, or the ability to perceive chemical cues in the environment, is believed to be one of the most important senses for salamanders.
Fig 2: Wood-colored Webfoot Salamander
All of the digits of this group of salamanders (Genus Bolitoglossa/Webfoot salamanders) are encased in fleshy webbing to one degree or another, which aids their arboreal lifestyle by allowing for extra traction on slippery wet vegetation. In addition, their tails are prehensile, helping to serve as anchors and stabilizing them as they move about.
Fig 3: Close-up of autotomized tail. Note how the skin folds around it, minimizing infection.
Interestingly, this specimen appears to have had a recent close encounter with a predator and lost its tail (last photo). Pseudoautotomy, or deliberate tail loss as an anti-predator defense, is wide-spread among the lungless salamanders. One of the most remarkable things about salamanders is their ability to regenerate broken tails completely, including the vertebrae! There are specific protective mechanisms in place after autotomy, where 1.) sphincter muscles in the tail contract to minimize arterial bleeding, and 2.) skin flaps contract around the wound to minimize infection while the body prepares to regenerate the amputated structure.
Fig 4: Profile view, showcasing the nasolabial protuberances below each nostril, an important structure in aiding chemosensation.
Source: Lenders, T. Amphibians of Costa Rica: A Field Guide. 2016. Cornell University Press.