Siphonops annulatus

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Siphonops annulatus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Gymnophiona
Clade: Apoda
Family: Siphonopidae
Genus: Siphonops
Species:
S. annulatus
Binomial name
Siphonops annulatus
(Mikan, 1820)
Synonyms

Caecilia interrupta Cuvier, 1829
Dermophis crassus Cope, 1885
Siphonops annulatus ssp. marmoratus Sawaya, 1937

Siphonops annulatus, the ringed caecilian, is a species of caecilian in the family Siphonopidae from South America.[2] It might have the broadest known distribution among terrestrial caecilian species.[3]

Description[edit]

Ringed caecilian measures 286–450 mm (11.3–17.7 in) in total length. The body is cylindrical and slightly wider than deep. It is bluish-black to slate in colour. The annular grooves that completely encircle the body (except the 3–4 posteriormost ones) are edged in white or cream.[3]

A team of scientists from Brazil and the United States discovered that these organisms have skin glands with different specialized functions. Glands on the head of the animals excrete lubricating mucous which may aid them in burrowing, while those on the tail region are packed with noxious chemicals, similar to the poison glands found in other amphibians such as toads and newts [4]

Siphonops annulatus, Ringed Caecilian, Zoology Museum, Cambridge

Distribution and habitat[edit]

Widely distributed east of the Andes: originally discovered in Brazil,[2] reported to exist in Argentina, Bolivia, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, and Venezuela. Its natural habitats are subtropical or tropical moist lowland forest, dry savanna, moist savanna, subtropical or tropical moist shrubland, subtropical or tropical seasonally wet or flooded lowland grassland, pastureland, plantations, rural gardens, and heavily degraded former forest.[1]

Reproduction[edit]

Nestlings are equipped with 44 spoon-shaped teeth to feed on the outer layer of their mother's skin. Young feed all at once for some seven minutes; then they all rest for three days as the female grows a new outer skin layer.[5] This phenomenon is known as maternal dermatophagy. This practice and morphological similarities are shared with its African relative Boulengerula taitana, suggesting it evolved over 100 million years ago.[6]

As detailed in a 2024 study, researchers collected 16 mothers of the species from cacao plantations in Brazil's Atlantic Forest and filmed them with their altricial hatchlings in the lab. The mothers remained with their offspring, which suckled on a white, viscous liquid from their cloaca, experiencing rapid growth in their first week. This milk-like substance, rich in fats and carbohydrates, is produced in the mother's oviduct epithelium’s hypertrophied glands, similar to mammal milk. The substance was released seemingly in response to tactile and acoustic stimulation by the babies. The researchers observed the hatchlings emitting high-pitched clicking sounds as they approached their mothers for milk, a behavior unique among amphibians. This milk-feeding behavior may contribute to the development of the hatchlings' microbiome and immune system, similar to mammalian young. The presence of milk production in caecilians that lay eggs suggests an evolutionary transition between egg-laying and live birth.[7][8][9]

References[edit]

  1. ^ a b IUCN SSC Amphibian Specialist Group (2014). "Siphonops annulatus". IUCN Red List of Threatened Species. 2014: e.T59593A43784684. doi:10.2305/IUCN.UK.2014-1.RLTS.T59593A43784684.en. Retrieved 11 November 2021.
  2. ^ a b Frost, Darrel R. (2015). "Siphonops annulatus (Mikan, 1820)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 13 April 2015.
  3. ^ a b "Siphonops annulatus". AmphibiaWeb: Information on amphibian biology and conservation. [web application]. Berkeley, California: AmphibiaWeb. 2015. Retrieved 13 March 2015.
  4. ^ Jared, Carlos; Mailho-Fontana, Pedro Luiz; Marques-Porto, Rafael; Sciani, Juliana Mozer; Pimenta, Daniel Carvalho; Brodie, Edmund D.; Antoniazzi, Marta Maria (2018-02-23). "Skin gland concentrations adapted to different evolutionary pressures in the head and posterior regions of the caecilian Siphonops annulatus". Scientific Reports. 8 (1): 3576. Bibcode:2018NatSR...8.3576J. doi:10.1038/s41598-018-22005-5. ISSN 2045-2322. PMC 5824806. PMID 29476100.
  5. ^ David Attenborough: Life in Cold Blood, page 28. BBC Books, 2008.
  6. ^ Wilkinson, Mark; Kupfer, Alexander; Marques-Porto, Rafael; Jeffkins, Hilary; Antoniazzi, Marta M; Jared, Carlos (June 2008). "One hundred million years of skin feeding? Extended parental care in a Neotropical caecilian (Amphibia: Gymnophiona)". Biology Letters. 4 (4): 358–61. doi:10.1098/rsbl.2008.0217. PMC 2610157. PMID 18547909.
  7. ^ Quaglia, Sofia (2024-03-07). "Bizarre, Wormlike and Oozing Milk for Their Babies". The New York Times. ISSN 0362-4331. Retrieved 2024-03-11.
  8. ^ Wake, Marvalee H. (7 Mar 2024). "Amphibian hatchlings find mother's milk". Science. 383 (1060-1061 (2024)): 1092. doi:10.1126/science.ado2094.
  9. ^ Mailho-Fontana, Pedro L.; Antoniazzi, Marta M.; Coelho, Guilherme R.; Pimenta, Daniel C.; Fernandes, Lígia P.; Kupfer, Alexander; Brodie, Edmund D.; Jared, Carlos (2024-03-08). "Milk provisioning in oviparous caecilian amphibians". Science. 383 (6687): 1092–1095. doi:10.1126/science.adi5379. ISSN 0036-8075.

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