# Thorius

Thorius, also known as minute salamanders, pigmy salamanders, or Mexican pigmy salamanders, is a genus of salamanders in the family Plethodontidae. They are endemic to Mexico and found in southern Veracruz and Puebla to Guerrero and Oaxaca.
Thorius is the most species-rich tropical salamander genus relative to its distribution area (Bolitoglossa and Pseudoeurycea have many more species but also much wider distribution areas). It is not uncommon for two or even three species to occur in the same place. In such cases, species have diverged in terms of body size and dentition, apparently facilitating niche differentiation.
The members of this genus are characterized by a small body — some species are less than 2 cm (0.79 in) in snout–vent length (tail roughly doubles the total body length). Their extreme miniaturization is accompanied by determinate growth and skeletal reduction. Their skeleton also shows unique features, such as ossifications of many elements that remain cartilaginous in other salamanders. Consequently, they are easy to distinguish from other salamanders. In contrast, they tend to be similar in appearance, making it difficult to distinguish species. However, molecular genetic methods have greatly facilitated identification of new species.

## Species

As of November 15, 2016, this genus is composed of the following 29 species:
| Binomial Name and Author | Common Name |
| Thorius adelos (Papenfuss and Wake, 1987) | Sierra Juarez salamander |
| Thorius arboreus Hanken & Wake, 1994 | Arboreal minute salamander |
| Thorius aureus Hanken & Wake, 1994 | Golden minute salamander |
| Thorius boreas Hanken & Wake, 1994 | Northern minute salamander |
| Thorius dubitus Taylor, 1941 | Acultzingo minute salamander |
| Thorius grandis Hanken, Wake & Freeman, 1999 | Grand minute salamander |
| Thorius hankeni Campbell, Brodie, Flores-Villela, and Smith, 2014 | Hanken's minute salamander |
| Thorius infernalis Hanken, Wake & Freeman, 1999 | Atoyac minute salamander |
| Thorius insperatus Hanken & Wake, 1994 | Vista Hermosa minute salamander |
| Thorius lunaris Hanken & Wake, 1998 | Orizaba minute salamander |
| Thorius macdougalli Taylor, 1949 | MacDougall's minute salamanders |
| Thorius magnipes Hanken & Wake, 1998 | Big-footed minute salamander |
| Thorius maxillabrochus Gehlbach, 1959 | Zoquitlan pigmy salamander |
| Thorius minutissimus Taylor, 1949 | Oaxacan minute salamander |
| Thorius minydemus Hanken & Wake, 1998 | La Hoya minute salamander |
| Thorius munificus Hanken & Wake, 1998 | McDiarmid minute salamander |
| Thorius narismagnus Shannon & Werler, 1955 | San Martin minute salamander |
| Thorius narisovalis Taylor, 1940 | Upper Cerro minute salamander |
| Thorius omiltemi Hanken, Wake & Freeman, 1999 | Omiltemi minute salamander |
| Thorius papaloae Hanken & Wake, 2001 | Papalo minute salamander |
| Thorius pennatulus Cope, 1869 | Veracruz minute salamander |
| Thorius pulmonaris Taylor, 1940 | Lower Cerro minute salamander |
| Thorius schmidti Gehlbach, 1959 | Schmidt's minute salamander |
| Thorius smithi Hanken & Wake, 1994 | Smith's minute salamander |
| Thorius spilogaster Hanken & Wake, 1998 | Spotted minute salamander |
| Thorius troglodytes Taylor, 1941 | Taylor's minute salamander |
| Thorius pinicola Parra-Olea et al., 2016 | Pine-dwelling minute salamander |
| Thorius longicaudus Parra-Olea et al., 2016 | Long-tailed minute salamander |
| Thorius tlaxiacus Parra-Olea et al., 2016 | Heroic minute salamander |