''Arthroleptides'' is a small genus of frogs in the family

Petropedetidae The Petropedetidae are a family of frogs containing two genera and 11 species. They are found in sub-Saharan tropical Africa and are sometimes known under common name African torrent frogs. They are inhabitants of the splash-water zone of clear ...

. Their common name is rocky river frogs. They are found in the mountains of

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

(Tanzania, Kenya, and probably Uganda). They have been considered to belong to ''

Petropedetes ''Petropedetes'' is a genus of frogs in the family Petropedetidae, found in sub-saharan tropical Africa. In 2002, the genus absorbed all three species of the genus '' Arthroleptides'', but they were moved back in 2014. The informally assigned com ...

'', which after exclusion of ''Arthroleptides'' is restricted to Central Africa. ''Arthroleptides'' species have distinct tympana and no external

vocal sac The vocal sac is the flexible Biological membrane, membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the voca ...

s. Males have femoral glands, and in the breeding state, spiny nuptial excrescences.

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 live on wet rocks out of water.

Taxonomy and systematics

The genus ''Arthroleptides'' was first established by German zoologist

Fritz Nieden Fritz Nieden (1883–1942) was a German zoologist who specialized in African herpetology. He worked as a zoologist at the ''Museum für Naturkunde'' in Berlin. His name is associated with Nieden's dwarf skink, '' Panaspis megalurus''. In 1911 he w ...

in 1911 after studying three specimens in the collection of the Berlin Zoological Museum. These specimens represented a single species and were collected two years prior in Amani, Muheza, Tanzania by herpetologist Paul Krefft and military commander Georg Martienssen. Nieden observed that the specimens bear some resemblance to frogs of the genera ''

Arthroleptis ''Arthroleptis'' is a genus of frogs in the family Arthroleptidae found in tropical sub-Saharan Africa. Their common names include screeching frogs, sometimes simply squeakers. Description These species are terrestrial breeding, with direct deve ...

'' and ''

'', yet also differed significantly enough from both that they belonged in a separate genus. He therefore established a new genus for this species, which he named '' Arthroleptides martiensseni'', with the generic name referencing the animal's similarities to ''Arthroleptis''. Nieden initially placed ''Arthroleptides'' within the family Ranidae, commonly referred to as the "true frogs". In 1931, American zoologist G.K. Noble established Petropedetinae as a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

within Ranidae and assigned the two genera ''Arthroleptides'' and ''Petropedetes'' into it. The two genera were united based on the fact that members of both possess a pair of dermal

scute A scute () or scutum (Latin: ''scutum''; plural: ''scuta'' "Scutum (shield), shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of Bird anatomy#Scales, birds. The ter ...

s on the upper surface of each digit, though they could be distinguished from each other by the fact that species of ''Arthroleptides'' lack

vomerine teeth The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms t ...

, a feature present in ''Petropedetes'' species. Later in 2006, Petropedetinae was elevated to family status and renamed as

. A paper published in 2005 concluded that the presence or absence of vomerine teeth can vary within a genus and is not significant enough a difference to warrant separation of ''Arthroleptides'' and ''Petropedetes'' into different genera. Because ''Petropedetes'' was named first, ''Arthroleptides'' was declared a

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. ...

of it, and the species assigned to ''Arthroleptides'' were moved into ''Petropedetes''. However, a phylogenetic study published in 2014 discovered that the ''Arthroleptides'' species do indeed form a

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

separate from the other ''Petropedetes'' species, and thus resurrected ''Arthroleptides'' as a valid taxon. The following

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

shows the position of the this genus within the family Petropedetidae according to the study:

Species

At the time it was established by Nieden, ''Arthroleptides'' was a

monotypic taxon In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of Genus, genera, the term ...

containing only ''A. martiensseni'', and thus it was designated as 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 ...

of the genus. However, later authors have assigned additional species to this genus. The three currently named species are: In addition, molecular evidence suggests that an undescribed species exists in the

Nguru Mountains The Nguru Mountains are a mountain range in Morogoro Region, Tanzania, Africa. They are part of the Eastern Arc Mountains. The mountains are predominantly covered with rainforest, home to 83 species of birds and African violets. Several forest res ...

References

{{Taxonbar, from=Q3768657 Petropedetidae Amphibians of Sub-Saharan Africa Amphibian genera Taxa named by Fritz Nieden Taxonomy articles created by Polbot