''Glandirana susurra'' 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, the "true frogs". It is

endemic Endemism is the state of a species being found only 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 foun ...

Sado Island is an island located in the eastern part of the Sea of Japan, under the jurisdiction of Sado City, Niigata Prefecture, Japan, with a coastline of . In October 2017, Sado Island had a population of 55,212 people. Sado Island covers an area of ...

, Japan. It is the only endemic amphibian of the island. It is genetically close to the widespread '' Glandirana rugosa'', but it is morphologically distinguishable and postzygotically isolated from the latter species.

Etymology

The specific name ''susurra'' is derived from the Latin ''susurrus'' meaning "whispering" and refers to the relatively quiet advertisement call of this species compared to those of other sympatric anuran ('' Hyla japonica'' and '' Rhacophorus arboreus'').

Evolution

Both ''Glandirana rugosa'' and ''Glandirana susurra'' are present on Sado Island, but their ranges do not overlap: ''G. susurra'' occurs on the central part of the island while ''G. rugosa'' in the south and in the north. Together with the fact that the race of ''G. rugosa'' on Sida Island is only distantly related to ''G. susurra'', this suggests that ''G. susurra'' speciated on Sato Island before the invasion of the present ''G. rugosa'' lineage. Experiments suggest that the postzygotic reproductive isolation between these lineages is nearly perfect, although it remains to be confirmed that this also applies to specimens originating from areas near the species boundary.

Description

Adult males measure and adult females in snout–vent length. The snout is rounded. The tympanum is distinct and the supratympanic fold is well-developed. The fingers and the toes are slender with slightly depressed tips; no webbing is present between the fingers while the toes have well-developed webbing. Dorsal skin has many dermal ridges of varying size. The dorsum is khaki-colored, whereas the abdomen is almost whitish anteriorly and yellow posteriorly. A mid-dorsal stripe is present in some individuals. Males lack vocal sac (present in ''G. rugosa'').

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 of stages 41–42 measure about in body length.

Habitat and conservation

''Glandirana susurra'' occurs near various bodies of water, such as rice fields, small streams, and ponds. It is known from elevations between

above sea level Height above mean sea level is a measure of a location's vertical distance (height, elevation or altitude) in reference to a vertical datum based on a historic mean sea level. In geodesy, it is formalized as orthometric height. The zero level ...

. Spawning occurs in ponds from middle May to early August. Adult frogs and at least some tadpoles spend their winter in the mud under water. As of late 2019, this species has not been included in the

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...

References

{{Taxonbar, from=Q3108497 susurra Frogs of Asia Endemic amphibians of Japan Amphibians described in 1979