Hyperolius thomensis

Hyperolius thomensis
Conservation status
	; Endangered (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Anura
Family:	Hyperoliidae
Genus:	Hyperolius
Species:	H. thomensis
Binomial name
	Hyperolius thomensis; Bocage, 1886
	range
Synonyms
	Rappia thomensis (Bocage, 1886); Nesionixalus thomensis (Bocage, 1886);

Hyperolius thomensis is a species of frog in the family Hyperoliidae. It is endemic to the island of São Tomé in São Tomé and Príncipe.^[1]^[2]^[3]^[4] Common names São Tomé reed frog,^[4] São Tomé giant reed frog,^[1] and Sao Tome giant treefrog have been coined for it.^[3] It is the largest Hyperolius species.^[3]^[5]

Taxonomy and systematics

The species was named by José Vicente Barbosa du Bocage in 1886.^[2] It is the type species of the genus Nesionixalus Perret, 1976. Its sister taxon Hyperolius molleri has also been placed in Nesionixalus. Together, these two species form a clade, but its recognition as a genus would render rest of Hyperolius paraphyletic.^[6] The two species can form hybrids.^[7]

Description

Adult males measure 27–41 mm (1.1–1.6 in) and adult females 36–49 mm (1.4–1.9 in) in snout–vent length.^[3]^[6] The dorsum is uniform brown or green to blue-green. The venter is marbled in white, orange and black. The ventral surfaces of the limbs are richly marbled in orange and black. Males have their dorsum densely beset with small spines. The pupil is horizontal.^[3]

Habitat and conservation

Hyperolius thomensis inhabits primary rainforest remnants usually at altitudes above 800 metres (2,600 ft), but occasionally as low as 350 metres (1,150 ft).^[1] Breeding takes place in tree holes where their tadpoles develop, and the same hole can be utilized by many individuals.^[1]^[5]

The threats to this species are poorly known, but it is probably impacted by habitat loss caused by agriculture, livestock, wood extraction, and human settlements. Its range includes the Parque Natural Obô de São Tomé.^[8]

Threats

Habitat Loss

Habitat loss, primarily driven by the conversion of land for agriculture and livestock, poses a significant threat to the São Tomé Giant Reed Frog. Additionally, the species faces challenges from habitat reduction due to activities such as wood extraction and the expansion of human settlements.^[1]

Amphibian Chytrid Fungus (Bd) Infection

A survey conducted for the presence of the amphibian chytrid fungus (Bd) revealed infections dating back to 2001. Despite the identification of the fungus, no instances of sick or deceased frogs have been reported in the field. However, the highly virulent strain of the pathogen (Bd-GPL) present on São Tomé Island raises concerns about its potential threat to the species.^[1]

References

^ ^a ^b ^c ^d ^e ^f ^g IUCN SSC Amphibian Specialist Group. (2020). "Hyperolius thomensis". IUCN Red List of Threatened Species. 2020: e.T56289A149751950. doi:10.2305/IUCN.UK.2020-3.RLTS.T56289A149751950.en. Retrieved 9 August 2021.
^ ^a ^b ^c Frost, Darrel R. (2021). "Hyperolius thomensis Bocage, 1886". Amphibian Species of the World: An Online Reference. Version 6.1. American Museum of Natural History. doi:10.5531/db.vz.0001. Retrieved 9 August 2021.
^ ^a ^b ^c ^d ^e "Hyperolius thomensis Sao Tome Giant Treefrog". AmphibiaWeb. University of California, Berkeley. 2008. Retrieved 17 October 2017.
^ ^a ^b Channing, Allan & Rödel, Mark-Oliver (2019). Field Guide to the Frogs & other Amphibians of Africa. Cape Town: Struik Nature. p. 192. ISBN 978-1-77584-512-6.
^ ^a ^b Drewes, R. C.; Stoelting, R. E. (2004). "The California Academy of Sciences Gulf of Guinea expedition (2001) II. Additions and corrections to our knowledge of the endemic amphibians of São Tomé́ and Príncipe". Proceedings of the California Academy of Sciences. 55 (31): 573–587.
^ ^a ^b Drewes, R. C.; Wilkinson, J. A. (2004). "The California Academy of Sciences Gulf of Guinea expedition (2001) I. The taxonomic status of the genus Nesionixalus with comments on the genus Hyperolius". Proceedings of the California Academy of Sciences. 55 (20): 395–407.
^ Bell, Rayna C.; Drewes, Robert C.; Zamudio, Kelly R. (2015). "Reed frog diversification in the Gulf of Guinea: Overseas dispersal, the progression rule, and in situ speciation". Evolution. 69 (4): 904–915. doi:10.1111/evo.12623. PMID 25715968. S2CID 43801840.
^ "DOPA: Parque Natural Obô de São Tomé". Joint Research Centre. Retrieved 1 November 2018.