Thorius pennatulus

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Thorius pennatulus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Plethodontidae
Genus: Thorius
Species:
T. pennatulus
Binomial name
Thorius pennatulus
Cope, 1869

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 (0.59 to 0.83 in). [2] It is endemic to the mountains of Veracruz, Mexico. [3]

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.

Plethodontidae family of amphibians

Plethodontidae, or lungless salamanders, are a family of salamanders. Most species are native to the Western Hemisphere, from British Columbia to Brazil, although a few species are found in Sardinia, Europe south of the Alps, and South Korea. In terms of number of species, they are by far the largest group of salamanders.

Tetrapod Superclass of the first four-limbed vertebrates and their descendants

Tetrapods are four-limbed animals constituting the superclass Tetrapoda. It includes extant and extinct amphibians, reptiles, and mammals. Tetrapods evolved from a group of animals known as the Tetrapodomorpha which, in turn, evolved from ancient Sarcopterygii around 390 million years ago in the middle Devonian period; their forms were transitional between lobe-finned fishes and the four-limbed tetrapods. The first tetrapods appeared by the late Devonian, 367.5 million years ago; the specific aquatic ancestors of the tetrapods, and the process by which they colonized Earth's land after emerging from water remains unclear. The change from a body plan for breathing and navigating in water to a body plan enabling the animal to move on land is one of the most profound evolutionary changes known. The first tetrapods were primarily aquatic. Modern amphibians, which evolved from earlier groups, are generally semiaquatic; the first stage of their lives is as fish-like tadpoles, and later stages are partly terrestrial and partly aquatic. However, most tetrapod species today are amniotes, most of those are terrestrial tetrapods whose branch evolved from earlier tetrapods about 340 million years ago. The key innovation in amniotes over amphibians is laying of eggs on land or having further evolved to retain the fertilized egg(s) within the mother.

Contents

Description

Thorius pennatulus is a very small species of salamander reaching a total length of up to 21 millimetres (0.83 in). The head is broad with a pointed snout, small nostrils and protuberant eyes. The tail and limbs are relatively long. The hands and feet are slender with short digits, the longest of which are pointed. The colour is generally pale brown with a regular pattern of darker markings on the back. [2]

Distribution and habitat

Thorius pennatulus has been found at several locations near Veracruz in Mexico at altitudes between 1,000 and 2,000 metres (3,300 and 6,600 ft). [2] It is a terrestrial species and during the day hides under rocks, in or under rotten logs or among leaf litter in banana plantations. [2] It inhabits cloud forest and lower altitude forest and is also found in damp coffee plantations. [1]

Veracruz State of Mexico

Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states that, along with Mexico city, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is Xalapa-Enríquez.

Cloud forest Type of 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

The young of Thorius pennatulus develop directly in the egg and do not have a larval stage. [1]

Larva juvenile form of distinct animals before metamorphosis

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.

Status

Thorius pennatulus is listed as "Critically Endangered" by the IUCN Red List of Threatened Species. [1] At one time it was a very common species in the limited area of forest and plantation where it is found but it underwent a large, unexplained decrease in population so that by the mid 1970s it was uncommon and since then it has continued to decline. There has been an increase in agricultural activities within its range but there is still plenty of good quality habitat remaining so its decline is a mystery. One individual was recorded in 2004 and another in 2006. [1]

Related Research Articles

The Sierra Juarez hidden salamander, also known as the Sierra Juarez moss salamander, or simply Sierra Juarez salamander, is a species of salamander in the family Plethodontidae. It is endemic to the Caribbean slopes of the Sierra de Juarez and Sierra Mazateca, Oaxaca, Mexico.

Ixalotriton parva, the dwarf false brook salamander, is a species of salamander in the family Plethodontidae. It is endemic to a small mountainous area of Mexico where its natural habitat is subtropical or tropical moist montane forests. It is threatened by habitat loss. There is some doubt whether this species should be classified as Pseudoeurycea parva or Ixalotriton parva.

Parvimolge is a genus of salamanders in the family Plethodontidae, the lungless salamanders. It is currently considered as monotypic, although this may yet change as molecular data suggest that it is embedded within a paraphyletic Pseudoeurycea. Parvimolge townsendi is endemic to the Sierra Madre Oriental in central and southern Veracruz, Mexico. It is represented by the species Parvimolge townsendi, commonly known as Townsend's dwarf salamander.

Aquiloeurycea praecellens. commonly known as the admirable false brook salamander, is a species of salamander in the family Plethodontidae. It is endemic to the Sierra Madre Oriental in Veracruz, Mexico. Its natural habitat is lowland tropical moist forest where it is threatened by habitat loss.

Thorius arboreus, commonly known as the arboreal minute salamander, 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, 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 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. It is one of the largest Thorius species.

Thorius boreas, commonly known as the boreal thorius, 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, commonly known as the Acultzingo pigmy salamander, 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, commonly known as the grand minute salamander, 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 infernalis, commonly known as the Atoyac minute salamander, is a species of salamander in the family Plethodontidae. It is endemic to Mexico where it is only known from its type locality in the Sierra Madre del Sur in central Guerrero. Its natural habitat is riparian vegetation along hillsides, presumably in forest. It is only known from two specimens, and it has not been seen since early 1980's. Much of the potential habitat is already converted into coffee plantations. It is threatened by habitat loss caused by expanding agriculture and human settlements.

Thorius lunaris, commonly known as the crescent-nostriled thorius, 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 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 minydemus, commonly known as the La Hoya minute salamander, is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from near its type locality near La Joya, Veracruz. Its natural habitats are cloud and pine-oak forests with many bromeliads.

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 narismagnus is a species of salamander in the family Plethodontidae. It is endemic to the San Martin Tuxtla volcano, in the Sierra de los Tuxtlas range in southern Veracruz state, Mexico. Its common name is San Martin pigmy salamander. Natural habitats of Thorius narismagnus are lowland and intermediate tropical forests. It occurs under rotten logs and among leaf-litter, and especially under fallen bromeliads.

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 pulmonaris, commonly known as the lower cerro pigmy salamander or Cerro San Felipe salamander, is a species of salamander in the family Plethodontidae. It is endemic to Oaxaca, Mexico.

Thorius spilogaster, commonly known as the spotted thorius, is a species of salamander in the family Plethodontidae. It is endemic to Mexico and only known from the south and southeast flanks of Pico de Orizaba in central Veracruz, at elevations of 2,500–2,725 m (8,202–8,940 ft) asl.

Thorius troglodytes, commonly known as Taylor's pigmy salamander, is a species of salamander in the family Plethodontidae that is endemic to Mexico. It is found only in mountains near the village of Acultzingo (Veracruz) at elevations of 2,380–3,000 m (7,810–9,840 ft) asl.

References

  1. 1 2 3 4 5 Parra-Olea, Gabriela; Wake, David; Raffaelli, Jean; Hanken, James (2008). "Thorius pennatulus". IUCN Red List of Threatened Species. Version 2012.1. Retrieved 2012-09-16.
  2. 1 2 3 4 Wake, David B. (2008). "Thorius pennatulus ". AmphibiaWeb. Retrieved 2012-09-16.
  3. Frost, Darrel R. (2015). "Thorius pennatulus Cope, 1869". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 13 July 2015.