Thorius aureus

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Thorius aureus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Plethodontidae
Genus: Thorius
Species:
T. aureus
Binomial name
Thorius aureus
Hanken & Wake, 1994 [2]

Thorius aureus, the golden thorius, is a species of salamander in the genus Thorius , the Mexican pigmy salamanders, part of the lungless salamander family. It is endemic to mountainous areas of north central Oaxaca State in Mexico. [1] [3] It is one of the largest Thorius species. [2]

Salamander order of amphibians

Salamanders are a group of amphibians typically characterized by a lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All present-day salamander families are grouped together under the order Urodela. Salamander diversity is most abundant in the Northern Hemisphere and most species are found in the Holarctic ecozone, with some species present in the Neotropical zone.

A genus is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses, in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.

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.

Contents

Etymology

The specific name aureus, Latin for golden or splendid, refers to the distinctive golden dorsal stripe that is characteristic of the species. [2]

In zoological nomenclature, the specific name is the second part within the scientific name of a species. The first part of the name of a species is the name of the genus or the generic name. The rules and regulations governing the giving of a new species name are explained in the article species description.

Description

Thorius aureus is a slender salamander with a narrow head and long tail. However, among Thorius it counts as a large and robust species, with males measuring 21.1–29.3 mm (0.83–1.15 in) and females 22.6–34.9 mm (0.89–1.37 in) in snout–vent length. The tail is relatively long and can be up to 1.16 times the snout–vent length in males. [2] It grows to a total length of about 57 millimetres (2.2 in) and is one of the largest species in the genus. Females have a rounded snout but this is more pointed in males. The eyes are protuberant and the nasolabial grooves distinct. The nostrils are small and oval and the upper jaw contains teeth (these are absent in many other members of the genus [4] ). The limbs are short with slender hands and feet. The digits are partially fused but are free at the tips. The dorsal surface is light brown and there is a distinctive broad golden stripe running along the spine, widest on the head and back and narrower at the shoulders. There are several brown chevron-shaped markings on the stripe. [5]

Nasolabial fold two skin folds in the face

The nasolabial folds, commonly known as "smile lines" or "laugh lines", are facial features. They are the two skin folds that run from each side of the nose to the corners of the mouth. They are defined by facial structures that support the buccal fat pad. They separate the cheeks from the upper lip. The term derives from Latin nasus for "nose" and labium for "lip".

Distribution and habitat

Thorius aureus is found in a restricted area around the peak of Cerro Pelón on the northern slopes of the Sierra Juárez, Oaxaca, Mexico, at altitudes of between 2,600 and 3,000 metres (8,500 and 9,800 ft) above sea level. It lives among the leaf litter on the forest floor of mixed woodland of oak, fir and pine and also in cloud forests. Being nocturnal, it hides during the daytime under rocks and fallen timber. [1]

Sierra Juárez, Oaxaca mountain in Mexico

The Sierra Juárez is a range of mountains in Oaxaca state, Mexico between latitudes 17°20'-17°50'N and longitudes 96°15'-97°00'W, with an area of about 1,700 km². It is part of the Sierra Madre de Oaxaca. The range is separated from the Sierra de Zongólica to the north by the Santo Domingo River, flowing through the Tecomavaca Canyon. It stretches south-eastward to the Cajones River and the Sierra de Villa Alta. The mountains are in the district of Ixtlán de Juárez in the Sierra Norte de Oaxaca region. The range is named after Mexico's only indigenous president, Benito Juárez, who was born here in 1806 in the small village of San Pablo Guelatao. The heavily wooded area is about 62 km (39 mi) from the city of Oaxaca on Federal highway 175, heading towards Tuxtepec.

Cloud forest rainforest

A cloud forest, also called a water forest and primas forest, is a generally tropical or subtropical, evergreen, montane, moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level, formally described in the International Cloud Atlas (2017) as silvagenitus. Cloud forests often exhibit an abundance of mosses covering the ground and vegetation, in which case they are also referred to as mossy forests. Mossy forests usually develop on the saddles of mountains, where moisture introduced by settling clouds is more effectively retained.

Biology

Little is known of the biology of this species. It is believed to feed on grubs, insects and other small invertebrates found among the leaf litter or under the bark of rotting logs. No eggs have been observed but they are thought to be laid on land and to undergo direct development into juvenile salamanders without passing through a larval stage. [5]

Status

Thorius aureus is listed as being "Critically Endangered" by the International Union for Conservation of Nature in its Red List of Threatened Species. This is because, although at one time common within its range, by 2008 no populations could be located, with only one sighting in the previous few years. Normally a resident of virgin forest, it does not adapt well to living in secondary growth, but the amount of logging within its range is insufficient to account for its dramatic population decline, which remains unexplained. [1]

International Union for Conservation of Nature international organisation

The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable".

Related Research Articles

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Álvarez del Toro's hidden salamander or Álvarez del Toro's salamander is a species of salamander in the family Plethodontidae. It is endemic to Mexico where it is known from its type locality near Jitotol as well as a nearby site on the Mexican Plateau in the Chiapas state.

Pseudoeurycea lineola is a species of salamander in the family Plethodontidae. It is endemic to the Sierra Madre Oriental near Cuautlapan, in the east-central Veracruz, Mexico, at elevations of 800–1,250 m (2,620–4,100 ft) above sea level. Molecular evidence suggests that it consists of two distinct species. It was the type species of genus Lineatriton.

Pseudoeurycea aurantia is a species of salamander in the family Plethodontidae. It is endemic to Oaxaca, Mexico and only known from its type locality near Peña Verde, which is the northernmost high peak in the Sierra de Juárez. Its common name is Peña Verde salamander.

The southern giant salamander is a species of salamander in the family Plethodontidae. It is endemic to Mexico and known from western and southern Oaxaca and eastern Guerrero. It is the largest tropical salamander; the holotype had a total length of about 24 cm (9.4 in) and weighed 58 grams (2.0 oz).

Thorius arboreus is a species of salamander in the family Plethodontidae. It is endemic to Sierra de Juarez, Oaxaca, Mexico. The specific name arboreus, derives from the Latin word arbor, meaning tree, referring to the arboreal habitat of this species.

Thorius boreas is a species of salamander in the family Plethodontidae. It is endemic to Oaxaca, Mexico, and only known from the Sierra Juárez. Its natural habitats are pine-oak and fir forests, often at forest edges. It is threatened by habitat loss (logging), although it does explain the dramatic decline that this species has seen.

Thorius dubitus is a species of salamander in the family Plethodontidae. It is endemic to Mexico where it is found in west-central Veracruz and adjacent Puebla. Its natural habitats are pine-oak cloud forests. It occurs under wood chips, logs, and rocks, and under the bark of logs and inside logs. It is threatened by habitat loss caused by logging, livestock, and subsistence agriculture.

Thorius grandis is a species of salamander in the family Plethodontidae. It is endemic to Mexico where it is found in west-central Sierra Madre del Sur in Guerrero. Its natural habitats are pine-fir and pine-oak-fir forests; it tolerates some habitat modification. It usually occurs under logs or the bark of fallen rotting logs. It is threatened by habitat loss caused by logging and expanding agriculture.

Thorius insperatus is a species of salamander in the family Plethodontidae. It is endemic to Sierra Juárez, Oaxaca, Mexico, and only known from the holotype collected near Vista Hermosa, at 1,500 m (4,900 ft) asl. The specimen was collected under a log in forest. The species is threatened by habitat loss caused by logging and expanding agriculture.

Thorius lunaris is a species of salamander in the family Plethodontidae. It is endemic to Pico de Orizaba, in Veracruz, Mexico, at elevations of 2,500–2,640 m (8,200–8,660 ft) asl. Its natural habitat is pine-oak forest where it occurs under the bark of stumps and fallen logs, in leaf-litter, and in piles of wood chips. This was formerly very abundant species is now very rare. It is threatened by habitat loss caused by logging and expanding agriculture.

Thorius macdougalli is a species of salamander in the family Plethodontidae. It is endemic to Oaxaca, Mexico, and is known from Cerro de Humo and Sierra de Juárez. Its natural habitat is pine-oak forest, but it also occurs in degraded habitats. It is threatened by habitat loss caused by clear-cutting and livestock grazing.

Thorius magnipes is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from near its type locality near Acultzingo, Veracruz. Its natural habitat is pine-oak forest. It can be found in bromeliads, leaf axils, under rocks and leaf-litter, and inside piles of wood chips. It is threatened by habitat loss caused by logging and agriculture.

Thorius munificus is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from near its type locality near Las Vigas, Veracruz. Its natural habitats are pine-oak and pine forests, woodlands, and Arbutus forests with abundant shrubby and ericaceous plants. The species is threatened by habitat loss caused by logging, agriculture, and human settlement.

Thorius narisovalis is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from near its type locality, Cerro San Felipe, Oaxaca. Its natural habitats are cloud forests and mixed forests. It lives under bark or under fallen trees.

Thorius pennatulus is a species of salamander in the family Plethodontidae and one of the smallest tetrapods, with adults reaching a length of about 15 to 21 millimetres . It is endemic to the mountains of Veracruz, Mexico.

Thorius pulmonaris is a species of salamander in the family Plethodontidae. It is endemic to Oaxaca, Mexico.

Thorius schmidti is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from the mountains near the village of Zoquitlán in southern Puebla, possibly also from Oaxaca. It is named after Karl Patterson Schmidt, American herpetologist.

Thorius smithi is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from near the towns of Vista Hermosa and Metates in Sierra Juárez, Oaxaca. Its natural habitats are cloud and tropical forests where it occurs on the ground under rocks and logs. It is a very rare species known only from two locations, despite attempts to find it. Presumably, habitat loss caused by logging and expanding agricultural development are threats to its forest habitat.

References

  1. 1 2 3 4 Parra-Olea, Gabriela; Wake, David; Hanken, James; García-París, Mario (2008). "Thorius aureus". IUCN Red List of Threatened Species . 2008: e.T59408A11931199. doi:10.2305/IUCN.UK.2008.RLTS.T59408A11931199.en.CS1 maint: Uses authors parameter (link)
  2. 1 2 3 4 Hanken, James; Wake, David B. (1994). "Five new species of minute salamanders, genus Thorius (Caudata: Plethodontidae), from northern Oaxaca, Mexico". Copeia. 1994 (3): 573–590. doi:10.2307/1447174. JSTOR   1447174.
  3. Frost, Darrel R. (2015). "Thorius aureus Hanken and Wake, 1994". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 11 July 2015.
  4. Rovito, Sean M.; Parra-Olea, Gabriela; Hanken, James; Bonett, Ronald M.; Wake, David B. (2013). "Adaptive radiation in miniature: the minute salamanders of the Mexican highlands (Amphibia: Plethodontidae: Thorius)". Biological Journal of the Linnean Society. 109 (3): 622–643. doi:10.1111/bij.12083.
  5. 1 2 "Golden Thorius (Thorius aureus)". EDGE. Zoological Society of London. Retrieved 21 July 2013.