The hole-in-the-head frog (''Huia cavitympanum'') is a species of

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

in the family Ranidae. It is the only member of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Huia''. It is found on the island of

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

. Its natural

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s are subtropical or tropical moist lowland

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s, subtropical or tropical moist

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

s, and torrential

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

s. It is threatened by

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

. The genus name honors Chinese herpetologist Shuchin Hu. ''H. cavitympanum'' is the only known species of frog to vocalize at only an ultrasonic level. The frogs have

eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pres ...

s recessed in the side of the skull, with an ear canal similar to

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s' anatomy. It appears to have evolved this higher pitch (more than 20 kHz) frequency of communication to circumvent the background noise of its waterfall habitat.

Taxonomy

''H. cavitympanum'' is now considered the only member of this genus, but it was formerly a

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

" wastebin taxon" with up to some 55

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. These included some originally placed into the genera '' Odorrana'' and ''Eburana'', which formed a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

cluster; indeed these two genera are sometimes treated as

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

s of ''Huia''. But many of the moves to ''Huia'' are now considered premature and ''Odorrana'' is now treated as valid as opposed to expanding ''Huia''.Cai et al. (2007), Stuart (2008) Up till 2021, the genus was still paraphyletic with respect to '' Meristogenys''. Suggested treatments included subsuming ''Meristogenys'' into the genus, or restricting ''Huia'' to the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

(''H. cavitympanum'') and what might be its closest living relatives (e.g. an undescribed species from

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

), and splitting off some other species of ''Huia'' - e.g. the Sumatran torrent frog (''H. sumatrana''). ''Meristogenys''

tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

s are furthermore characterized by a split and ridged upper lip not found in the hole-in-the-head frog, indicating that the genera should kept separate. This was ultimately resolved in 2021 by splitting off all non-''cavitympanum'' species into the new genus ''

Wijayarana ''Wijayarana'' is a group of true frogs found in Southeast Asia. Their common name is Wijaya cascade frogs. Many are commonly known as " torrent frogs" after their favorite habitat - small rapid-flowing mountain and hill streams -, but this name ...

'', leaving the genus ''Huia'' monotypic.

References

* Cai, Hong-xia; Che, Jing, Pang, Jun-feng; Zhao, Er-mi & Zhang, Ya-ping (2007). "Paraphyly of Chinese ''Amolops'' (Anura, Ranidae) and phylogenetic position of the rare Chinese frog, ''Amolops tormotus''". ''

Zootaxa ''Zootaxa'' is a peer-reviewed scientific mega journal for animal taxonomists. It is published by Magnolia Press (Auckland, New Zealand). The journal was established by Zhi-Qiang Zhang in 2001 and new issues are published multiple times a week ...

'' 1531: 49–55
PDF abstract and first page text
* Stuart, Bryan L. (2008). "The phylogenetic problem of ''Huia'' (Amphibia: Ranidae)". ''

Molecular Phylogenetics and Evolution ''Molecular Phylogenetics and Evolution'' is a peer-reviewed scientific journal of evolutionary biology and phylogenetics. The journal is edited by E.A. Zimmer. Indexing The journal is indexed in: * EMBiology *Journal Citation Reports *Scopus ...

'' 46 (1): 49-60. (HTMl abstract)

External links

* *https://www.sciencedaily.com/releases/2009/05/090508192231.htm True frogs Amphibians of Indonesia Amphibians of Malaysia Endemic fauna of Borneo Taxonomy articles created by Polbot Amphibians described in 1896 Amphibians of Borneo {{Ranidae-stub

Taxonomy

See also

References

External links