''Alcalus rajae'', sometimes known as king dwarf mountain frog, is a species of

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

in the family

Ceratobatrachidae The Ceratobatrachidae are a family of frogs found in the Malay Peninsula, Borneo, the Philippines, Palau, Fiji, New Guinea, and the Admiralty, Bismarck, and Solomon Islands. Taxonomy Ceratobatrachidae was formerly treated as a subfamily (i.e ...

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 subfamily botanical names with "-oideae", and zoologi ...

Alcalinae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Kalimantan Kalimantan () is the Indonesian portion of the island of Borneo. It constitutes 73% of the island's area. The non-Indonesian parts of Borneo are Brunei and East Malaysia. In Indonesia, "Kalimantan" refers to the whole island of Borneo. In 2019, ...

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

(Indonesia), and known from its type locality in the

Bukit Baka Bukit Raya National Park Bukit Baka Bukit Raya National Park ( id, Taman Nasional Bukit Baka Bukit Raya) is a national park located on Borneo Island, Indonesia. It is named after the mountains of Bukit Baka () and Bukit Raya (),Ministry of Forestry of Indonesia"Taman ...

, as well as the Gunung Penrissen Nature Reserve, both in the

West Kalimantan West Kalimantan ( id, Kalimantan Barat) is a province of Indonesia. It is one of five Indonesian provinces comprising Kalimantan, the Indonesian part of the island of Borneo. Its capital city is Pontianak, Indonesia, Pontianak. The province has ...

province, and from the Meratus Protected Forest in the

South Kalimantan South Kalimantan ( id, Kalimantan Selatan) is a Provinces of Indonesia, province of Indonesia. It is the smallest province in Kalimantan, the Indonesian territory of Borneo. The provincial capital was Banjarmasin until 15 February 2022 when it wa ...

province. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''rajae'' refers to the type locality: Bukit Raya is the highest mountain in Kalimantan, getting its name from the

Indonesian Indonesian is anything of, from, or related to Indonesia, an archipelagic country in Southeast Asia. It may refer to: * Indonesians, citizens of Indonesia ** Native Indonesians, diverse groups of local inhabitants of the archipelago ** Indonesian ...

word ''raya'' (or ''raja''), signifying the majestic size of the peak. It also alludes to the relatively large size of this species relative to its (then) congeners.

Description

Adult females reach in snout–vent length. The overall appearance is stocky. The snout is rounded. The head is slightly wider than it is long. The tympanum is not externally visible, with tympanic annulus being hidden under skin and covered with muscle. A distinct supratympanic fold is nevertheless present. The limbs are short. The fingers have narrow fringes and wide, truncated and flattened tips (discs). The toes are essentially fully webbed and bear similar discs as the fingers. Skin is granular. Dorsal coloration is uniformly light to dark brown or blackish, without any specific markings. The hind limbs have three indistinct darker crossbars. There are few, scattered white spots on the sides of body and head, the lower parts of the flanks, as well as on the hands and limbs. All digits have a white crossbar straddling middle of the truncated, flat disk. The

iris Iris most often refers to: *Iris (anatomy), part of the eye *Iris (mythology), a Greek goddess * ''Iris'' (plant), a genus of flowering plants *Iris (color), an ambiguous color term Iris or IRIS may also refer to: Arts and media Fictional enti ...

is dark brown with indistinct reticulation.

Habitat and conservation

''Alcalus rajae'' occurs in primary undisturbed and secondary forests near seepage areas close to small and slow-moving streams and swamps. Its altitudinal range is . Its morphology (fully webbed toes and absence of tympanic annulus) suggests that it is aquatic. It is probably an egg-laying species. This species occurs in the well-protected Bukit Baka-Bukit Raya National Park, but habitat loss is occurring outside the reserve. Meratus Protected Forest also has intact forest remaining. In contrast, most of the original vegetation in the Gunung Penrissen Nature Reserve has been lost because of slash-and-burn activities and tourism and recreational development. Outside the known sites, the species would be likely suffering from deforestation caused by oil palm plantations and forestry concessions.

References

{{Taxonbar, from=Q3150937 rajae Endemic fauna of Borneo Endemic fauna of Indonesia Amphibians of Indonesia Amphibians described in 2011 Amphibians of Borneo