lungless salamander
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What is a lungless salamander?
A lungless salamander is any of over 370 species belonging to the family Plethodontidae, the largest group of salamanders. They are largely dependent on cutaneous respiration, which means they breathe through their moist skin.
Lungless salamanders are predominantly found in the Americas, from Canada to Brazil. A few species also live in Sardinia, northern Italy, and the Korean peninsula. Adults range in size from approximately 25 mm to 36 cm in head and body length. They possess a pair of nasolabial grooves that extends from their upper lip to their nostril, which they use to detect odour particles.
Plethodontid lifestyles vary widely, ranging from fully aquatic to entirely terrestrial.
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Where are lungless salamanders commonly found?
Lungless salamanders (Plethodontidae) are the largest group of salamanders, with over 370 species. They are mainly found in the Americas, from southern Canada to the Amazon basin in Brazil. Some species can also be found in Sardinia, northern Italy, and the Korean peninsula.
Most salamanders live in moist, forested habitats. They are common in aquatic and terrestrial communities in temperate North America, western Europe, Japan, and China. However, lungless salamanders are diverse in the humid tropical montane forests of Mexico, Central America, and northwestern South America. Web-toed salamanders of the genus Hydromantes prefer nonforested areas and inhabit rock crevices in desert-like environments in Europe, California, and Baja California.
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What adaptations help lungless salamanders survive in their environment?
Lungless salamanders (Plethodontidae) have adaptations that allow them to thrive without lungs. These amphibians rely on cutaneous respiration for gas exchange through their moist skin and the mucous membrane in their mouths and throats.
To aid in finding food, lungless salamanders possess nasolabial grooves between their upper lip and nostril that help them identify food sources and chemical cues.
Plethodontidae exhibit diverse lifestyles ranging from aquatic to terrestrial. Some species lay aquatic eggs that hatch into free-swimming larvae, while others undergo direct development within the egg capsule, hatching as adult-like juveniles.
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How do lungless salamanders differ from other types of salamanders?
Lungless salamanders (Plethodontidae) form the largest group of salamanders, with over 370 species. Unlike other salamanders, they lack lungs and depend on cutaneous respiration, absorbing oxygen through their moist skin and the mucous membrane in their mouths and throats.
All lungless salamanders have nasolabial grooves that support their sense of smell. While most salamanders have an aquatic larval stage, lungless salamander eggs develop entirely on land, hatching as miniature adults.
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Why is studying lungless salamanders important for understanding amphibian evolution?
Lungless salamanders (Plethodontidae) are valuable for understanding amphibian evolution because they rely on cutaneous respiration, absorbing oxygen through their skin and the mucous membrane in their mouths and throats. This adaptation is significant given that most amphibians use gills or lungs for respiration.
The study of lungless salamanders provides insights into evolutionary patterns such as direct development, where the aquatic egg and free-swimming larval stages are eliminated. Instead, juveniles hatch as miniature adults. Also, the evolution of parallel lines, loss of lungs, and the presence of larval traits in adults (paedomorphosis) contribute to the diversity and complexity of amphibian evolution.
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lungless salamander, (family Plethodontidae), any of more than 370 species of lungless amphibians dependent largely on cutaneous respiration (gas exchange through moistened skin). Plethodontidae is the largest group of salamanders, and its members occur predominantly in the Americas from southern Canada to the Amazon basin in Brazil. A few species also occur spottily in Sardinia, northern Italy, and the Korean peninsula. Adult plethodontids range in size from approximately 25 mm (1 inch) in head and body length in the Mexican pygmy salamander (Thorius) to 36 cm (14 inches) in Bell’s false brook salamander (Pseudoeurycea bellii). The length of the animal’s tail usually equals or slightly exceeds its head and body length. Most plethodontid species are between 40 and 120 mm (1.6 and 4.7 inches) in head and body length. Since they lack lungs, all plethodontids breathe through their skin and the mucous membrane in the mouth and throat; these surfaces must remain moist at all times in order to absorb oxygen.
All lungless salamanders possess a pair of nasolabial grooves, and each groove extends from the upper lip to a nostril. The salamander touches its snout to a surface (nose tapping), and capillary action moves odour particles up the groove into the sensory cells in the vomeronasal organ of the nose. Plethodontids rely on odours for chemical alarm cues, directions to food sources, and cues for courtship and other social behaviour. Smaller species eat a wide variety of small invertebrates that range from worms to insects and mites. Larger plethodontids also consume invertebrates, and some of them even prey on other salamanders.
Plethodontid lifestyles vary widely and range from fully aquatic to entirely terrestrial. Some terrestrial forms are semiburrowing, whereas others are arboreal (tree dwelling). About 35 species—spanning the genera Eurycea, Gyrinophilus, Pseudotriton, and Stereochilus—lay aquatic eggs that hatch into free-swimming larvae, which eventually metamorphose into adultlike juveniles. Other species are characterized by embryos that complete their development within the egg capsule and hatch directly as adultlike juveniles.
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Family Plethodontidae is divided phylogenetically into the subfamilies Desmognathinae and Plethodontinae. The desmognathines are made up of two genera (Desmognathus and Phaeognathus) and 18 species strictly limited to eastern North America. Desmognathine salamanders range from fully terrestrial forms, such as the Red Hills salamander (P. hubrichti), to aquatic forms, such as the black-bellied salamander (D. quadramaculatus). All desmognathine species lay eggs, and females guard the eggs regardless of whether the eggs hatch into larvae or into adultlike juveniles.
The plethodontines are made up of more than 25 genera and 250 species that occur throughout the range of the family. All are egg layers, and the majority of species in this group have eggs that develop directly into adultlike forms; however, some aquatic species have free-living larvae. Most other plethodontines are forest species, and over four dozen of these belong to Plethodon, the most diverse North American genus. The majority of species in this genus live on the floors of forests and woodlands that have been fragmented by human activity. Bolitoglossa and Pseudoeurycea, two genera found in mountainous areas in the New World tropics, possess their greatest diversity in middle-elevation cloud forests; some of these species are arboreal and live in epiphytes. Web-toed salamanders, plethodontines of the genus Hydromantes, prefer nonforested areas; they mainly inhabit rock crevices in desertlike environments in Europe, California, and Baja California. The embryos of all terrestrial and arboreal plethodontines undergo direct development and hatch into adultlike forms. Females of most species guard their eggs.