General Description and Taxonomy
Desmognathus wrighti was named and discovered by King in 1936. The pygmy salamander’s natural habitat includes temperate forests, intermittent rivers, and freshwater springs. This species small size places it among the smallest salamanders in the world. D. wrighti adult size is in the range of the sizes of the genus Thorius, which are neo-tropical and considered the smallest urodeles in the world. The genus Desmognathus consists of nineteen species which all vary in body size, life history, and habitat. The most basic way of sorting the species in this genus is by body size and distance they are found from streams which they inhabit.
In 2010, there was a taxonomic revision to Desmognathus wrighti. This revision was based on genetic and ecological analyses. This divergence has been reported by DNA sequencing, but further research shows several differences in the body type and ventral pigmentation. An ecological niche analysis was completed on two niches separated by the French Broad River and significant morphological variation was found between the two lineages. Findings show differences in snout-vent length, body condition, and head width, suggesting that there are two distinct and separately evolving lineages in Desmognathus wrighti. The diverging northern lineage, Desmognathus organi, is the new species described by Crespi and Browne in 2010. The revision to the taxonomic Desmognathus wrighti was seen needed for the northern pygmy salamander to reflect the genetic, ecological, and geographical differences in the two different populations located north and south of the French Broad River. The original species Desmognathus wrighti described by King more accurately describes the linage from the southern part of the French Broad River and the morphological descriptions described on this page. The new species Desmognathus organi, the Northern pygmy salamander, is a sister taxon to D. wrighti. Differences of D. organi from its sister taxon includes a slightly larger body length, wider heads, and the ventral gold iridophore patters are absent. Also, D. organi is found in higher elevations north of the French Broad River including Tennessee, North Carolina, and Virginia.
Read more about this topic: Pygmy Salamander
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