Brasilotyphlus

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Brasilotyphlus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Gymnophiona
Clade: Apoda
Family: Siphonopidae
Genus: Brasilotyphlus
Taylor, 1968

Brasilotyphlus is a genus of caecilians in the family Siphonopidae. It was considered monotypic, containing only the species Brasilotyphlus braziliensis . However, two recently described species, Brasilotyphlus guarantanus and Brasilotyphlus dubium , have been placed in this same genus. All three species are endemic to Brazil. [1] This genus has also been suggested as paraphyletic to Microcaecilia . [1]

Contents

Species

History

The genus was discovered less than a century ago, and relatively little is known about it to date. [2] The physical shape and structure of Brasilotyphlus has been recorded, while information concerning even basic biology, such as physiology and habitat, of this genus is lacking. Currently, it is known to be a subterranean genus living in the rainforest of Brazil. [2] Further, the threats to this genus are currently unknown, as its ability to adapt to a secondary habitat has not been observed. [2] Both species have been located exclusively in Brazil. Their known locations are small and restricted. They were found independent of each other, and their habitats may not overlap. The closest known habitats for the two species, with respect to each other, are approximately 950 km apart. [3] Beyond this there is little to no knowledge as to the distribution of this genus, which makes locating a subject for research quite difficult. [4] The first of these species, Brasilotyphlus braziliensis has not even been seen since 1997. [2] Even the classification of this genus is a source of confusion, as not all scholars agree on the phylogeny. [5] To date, no photographs have been published of the living Brasilotyphlus brasiliensis. [3]

Phylogeny

This genus has been strongly suggested to be put under taxonomic review. [2] It was originally declared its own genus because of its distinct combination of characteristics. Namely, it had premaxillary teeth which did not extend to the level of the posterior nasal apertures. It had vomerine teeth which were organized in rows of compact semicircles and were separated from the palatine teeth by a gap. The eye was not visible externally, instead covered by thick bone. There were small tentacles which, in comparison to other caecillians of similar size, were much closer to the mouth. Lastly, the specimen has a weak vertical keel on the terminal part of the body. However, the finding of the second species, B. guarantanus, has redefined the genus characteristics. Now, the genus is described as diminutive caecilian, being no more than 305 mm in length. [3]

Cranial characteristics

The species B. guarantanus has been reported to have sexual dimorphism in the head. [6] That is, the head of the male is wider than the head of the female. The genus Brasilotyphlus also has an open eye socket. [7] The eye was originally thought to not be visible from the outside or not be present at all. [8] One dissection concluded that the eyes were either too small to be seen by the naked eye, or not present. [3] The bones of the skull are transparent, allowing the brain to be seen through them. [8] The tentacular opening has a greater posterior distance from the nostril then that of other known Gymnophiona and is much closer to the mouth. [8] Its tentacles are also relatively small. [3] All specimens of B. brasiliensis have been flattened or otherwise damaged. [8] Measurements are therefore estimated. [8] Most of the data on this genus is taken from the species Brasilotyphlus guarantanus. [3]

Dentition

The genus Brasilotyphlus has a three-series dentition. The inner mandibular teeth are absent. The maxillary teeth can extend to or past the choanae, but do not always. [3] It has a large diastema, or gap, between its vomerine and palatine teeth. [7] It contains premaxillary, maxillary, prevomerine, and palatine teeth. [8] Most teeth monocuspid. The prevomerine and palatine teeth are the only exceptions and they are bicuspid. The front end of the tongue is attached to the gums directly behind the dentary teeth. [3]

Scales

The genus Brasilotyphuls has dermal scales present in its folds. The scales are mostly present on the posterior end of the body. [3] The species Brasilotyphlus braziliensis has scales which start around the 25th fold of the body. [8] The scales start off very small. [8] At the middle of the body there are two rows of scales. [8] The remaining posterior end of the body has five rows of scales on each fold and they are irregularly organized. [8] It has a brown coloration throughout. [8]

Related Research Articles

<span class="mw-page-title-main">Caecilian</span> Order of amphibians

Caecilians are a group of limbless, vermiform (worm-shaped) or serpentine (snake-shaped) amphibians with small or sometimes nonexistent eyes. They mostly live hidden in soil or in streambeds, and this cryptic lifestyle renders caecilians among the least familiar amphibians. Modern caecilians live in the tropics of South and Central America, Africa, and southern Asia. Caecilians feed on small subterranean creatures such as earthworms. The body is cylindrical and often darkly coloured, and the skull is bullet-shaped and strongly built. Caecilian heads have several unique adaptations, including fused cranial and jaw bones, a two-part system of jaw muscles, and a chemosensory tentacle in front of the eye. The skin is slimy and bears ringlike markings or grooves and may contain scales.

<i>Boulengerula taitana</i> Species of amphibian

Boulengerula taitana is a species of caecilian. It is endemic to the Taita Hills region of southeast Kenya. Boulengerula taitana are unique caecilians in appearance, fertilization type, and parental care. From their similar shape and presentation to worms, and their internalized fertilization, they set themselves apart from many other amphibians. D. taitana interactions between mothers and newly hatched young is unique in that the mother uses her own skin as a food resource for offspring. This species also has physiological adaptations in place to increase oxygen uptake and affinity to fit their underground lifestyle. The Boulengerula taitana differentiates itself from its close relatives in ways rarely documented and researched before.

<i>Atretochoana</i> Genus of amphibians

Atretochoana eiselti is a species of caecilian originally known only from two preserved specimens discovered by Sir Graham Hales in the Brazilian rainforest, while on an expedition with Sir Brian Doll in the late 1800s, but rediscovered in 2011 by engineers working on a hydroelectric dam project in Brazil. Until 1998, it was known only from the type specimen in the Naturhistorisches Museum, Vienna. Originally placed in the genus Typhlonectes in 1968, it was reclassified into its own monotypic genus, Atretochoana, in 1996. It was also found to be more closely related to the genus Potamotyphlus than Typholonectes. The species is the largest of the few known lungless tetrapods, and the only known lungless caecilian.

Chthonerpeton perissodus is a species of caecilian in the family Typhlonectidae. It is endemic to Minas Gerais, Brazil, and only known from its imprecise type locality, Rio Pandeiro. Only three specimens are known. The common name Minas Gerais caecilian has been coined for this species.

<i>Microcaecilia</i> Genus of amphibians

Microcaecilia is a genus of caecilians in the family Siphonopidae.

Microcaecilia taylori is a species of caecilian in the family Siphonopidae. It is known from two widely separated populations, one in southern Suriname and other one in Pará, Brazil, south of the Amazon River. It is not clear whether the gap is real or whether the populations south of the Amazon River represent a distinct species. Microcaecilia taylori was confused with Microcaecilia marvaleewakeae before the latter was described in 2013.

Mimosiphonops is a genus of caecilians in the family Siphonopidae. The genus is definitely known only from the state of Rio de Janeiro, Brazil. They are sometimes known as the worm patterned caecilians.

<i>Schistometopum thomense</i> Species of amphibian

Schistometopum thomense is a species of amphibian in the family Dermophiidae, endemic to São Tomé and Ilhéu das Rolas. It is found in most soils on São Tomé, from tropical moist lowland forests to coastal coconut plantations. It is absent only from the driest northern areas of the island. It is typically around 30 cm (12 in) in length, and is often bright yellow. The size of S. thomense can vary throughout São Tomé, however, and it is the only known caecilian to follow Bergmann's rule, which states that a decreasing temperature due to factors such as increasing altitude will cause an increase in the body size of endothermic vertebrate species. The island of São Tomé is a massive shield volcano, and it therefore has differing altitudes throughout the island, potentially resulting in the size diversity of S. thomense. This species may be referred to as the São Tomé caecilian, as the Agua Ize caecilian, or as the island caecilian, or by the local name of cobra bobo.

<i>Siphonops annulatus</i> Species of amphibian

Siphonops annulatus, the ringed caecilian, is a species of caecilian in the family Siphonopidae endemic to South America. It may have the broadest known distribution of any terrestrial caecilian species.

Ainsworth's salamander is an extinct species of salamander in the family Plethodontidae. It was endemic to the United States and only known from its type series collected in Jasper County, Mississippi in 1964. Later research has cast doubt to its validity; it might be a junior synonym of Plethodon mississippi.

Indotyphlus is a small genus of caecilians in the family Grandisoniidae. As caecilians in general, they superficially resemble earthworms. The genus is endemic to the Western Ghats, India. They are sometimes known as Battersby's caecilians.

Brasilotyphlus braziliensis is a species of caecilian in the family Siphonopidae. It was considered monotypic within Brasilotyphlus but a recently described species has been placed in this same genus. It is endemic to Brazil. Its habitat includes natural forests, dry tropical or subtropical. It is in danger of extinction because of the loss of its natural habitat.

Brasilotyphlus guarantanus is a species of caecilian in the family Caeciliidae. It was described in 2009 from a specimen collected in the north part of Mato Grosso, Brazil.

<span class="mw-page-title-main">Siphonopidae</span> Family of amphibians

The Siphonopidae are the family of common caecilians. They are found in Central and South America. Like other caecilians, they superficially resemble worms or snakes.

Ichthyophis moustakius, the Manipur moustached caecilian, is a species of caecilian in the family Ichthyophiidae. It is endemic to Northeast India. This species exhibits broad lateral yellow stripes from the anterior part of its tail, along its mandibles, between its nares, as well as elsewhere. The animal can reach a length of 300 millimetres (12 in). Its head is somewhat U-shaped and fairly short; scales are absent on its collars. The species' name is derived from the Greek word moustakius, meaning "moustache", due to the yellow arched stripes it possesses.

Ichthyophis sendenyu, the Sendenyu striped ichthyophis, is a species of caecilian found in India. This species of Ichthyophis possesses broad and solid lateral yellow stripes from about the level of the posterior of its disc to its eye level on the upper jaw, while arched yellow stripes extend to its nares. Its length does not exceed 350 millimetres (14 in). Its head is U-shaped and short. Scales are present in anteriormost grooves, with five to eight rows placed posteriorly on its dorsum. It is named after Sendenyu village, Nagaland, where the species was first found.

Marvalee Hendricks Wake is an American zoologist and professor at the University of California, Berkeley, known for her research in the biology of caecilians and vertebrate development and evolution. A 1988 Guggenheim Fellow, she has served as president of the American Institute of Biological Sciences, the American Society of Ichthyologists and Herpetologists, Society for Integrative and Comparative Biology, International Union of Biological Sciences, and the International Society of Vertebrate Morphology. She is a fellow of the American Association for the Advancement of Science and the California Academy of Sciences, and is a member of the American Academy of Arts and Sciences.

Microcaecilia grandis is a species of caecilian in the family Siphonopidae. It is endemic to Suriname and only known from the Lely Mountains. It measures around 318 mm (12.5 in) in total length, and possesses bicuspid vomeropalatine teeth as well as more than 20 premaxillary-maxillary teeth.

Brasilotyphlus dubium is a species of caecilian in the family Caeciliidae. It is endemic to the state of Roraima in northern Brazil. It was described in 2018.

Amazops is a monotypic genus of caecilian in the family Rhinatrematidae. It contains only one species, Amazops amazops. It is endemic to Ecuador and is only known from a single specimen collected around 1990 from the Virgen La Dolores Farm in the province of Orellana. The individual was found in very soft, red and muddy soil under some rocks on a dirt road in a portion of the Ecuadorian Amazon at an altitude of about 1000 meters above sea level. It is presumed that like most other rhinatrematids, it is oviparous and is aquatic during its larval phase.

References

  1. 1 2 Maciel, A.O. & M.S. Hoogmoed, "Taxonomy and distribution of caecilian amphibians (Gymnophiona) of Brazilian Amazonia, with a key to their identification" Zootaxa, 2984: 1-53
  2. 1 2 3 4 5 Miguel Trefaut Rodrigues, Claudia Azevedo-Ramos, Mark Wilkinson (2004). "Brasilotyphlus braziliensis". IUCN Red List of Threatened Species . 2004: e.T59500A11949756. doi: 10.2305/IUCN.UK.2004.RLTS.T59500A11949756.en . Retrieved 15 November 2021.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. 1 2 3 4 5 6 7 8 9 Adriano O. Maciel, Tami Mott, Marinus S. Hoogmoed, "A Second species of Brasilotyphlus (Amphibia:Gymnophiona:Caeciliidae) from Brazilian Amazonia" Zootaxa 2009
  4. Cardoso Pinheiro, Leandra, Youszef Oliveira Da Cunha Bitar, Ulisses Galatti, Selvino Neckel-Oliveira, and Maria Cristina Dos Santos-Costa "Amphibians from Southeastern State of Pará: Carajás Region, Northern Brazil" Archived 2016-03-04 at the Wayback Machine Check List 8.4 (2012): 693-702
  5. Unknown, "Brasilotyphlus Braziliensis.", AmphibiaWeb – Inaturalist,
  6. Mott, Tami, Mario Ribeiro De Moura, Adriano Oliveira Maciel, and Renato Neves Feio, "Morphological Variation and Geographical Distribution of Luetkenotyphlus Brasiliensis (Gymnophiona: Siphonopidae)," Phyllomedusa 10.2 (2011): 153-63,
  7. 1 2 Wake, Marvalee, and Maureen Donnelly, "A New Lungless Caecilian (Amphibia: Gymnophiona) from Guyana" Royal Society Publishing
  8. 1 2 3 4 5 6 7 8 9 10 11 Edward Taylor, "The Caecilians of the World" Kansas Press 1968