Taxonomy

(Barker et al.,1995, Brodie Jnr. et al. 1998,Davies et al., 1986, Davies and McDonald, 1998. Tyler et al. 1980)

Although this genus has been known since 1841, its members are known to be hard to distinguish. Uperoleia mimula remained undescribed separately until 1986. For a long time members of this species were listed under other Uperoleia species ie: U. marmorata, U. lithomoda. The holotype specimen was collected near Laura, in Cape York at Lakefield National Park by Keith Mc Donald and B. Ryan in 1981. It is very similar morphologically to its sympatric species U. lithomoda which has stronger dorsal marking and a different call but a far greater geographical range extending across to W.A. U. lithmoda is the only other Uperoleia species found in U. mimula's range.

Description

(Barker et al.,1995, Cameron and Cogger 1992, Davies et al., 1986, Davies and McDonald, 1998)

Uperoleia mimula is a stout, small, fossorial frog that has short limbs and no discs. Its dorsal surface has a slightly uneven .wrinkled skin, It is pale to dull brown above with darker brown to reddish brown patches on the dorsal head area.The ventral surface is stippled with dull grey on a creamish ground with the throat area similar. The limbs are transversed with narrow bands of darker brown on a paler field. It has bright scarlet patches on the inside of the thigh and in the groin area. On the side of the neck topping the forelimbs medium sized parotoid glands are easily seen. Well developed inguinal glands are also present as are coccygeal glands. There are no vomerine teeth or maxillary teeth. The tympanum is not visible. Both inner and outer metatarsal tubercles are present and rounded. The fingers are without webbing and in the toes webbing is very basal or absent.

Size (snout-vent).The maximum size recorded for U. mimula is 28.4 mm. Females are said to range between 21mm and 28mm apx with males from 20mm. to 28mm. apx. However adults have been found as small as 16mm.

Adult

Geographic range.

(Cameron and Cogger, 1992, Barker et al., 1995, Davies et al.,1986)

On mainland Australia U. mimula is found on Cape York Peninsula and its range extends south on the eastern coastal areas to Townsville and Magnetic Island. It is also found on Torres Strait Islands and southern New Guinea in the Morehead area.

Calls

( Barker et al., 1995, Cameron and Cogger, 1992,Davies et al.,1986.Davies et al., 1993)
Although similar, it is distinguished from U. lithomoda by the length of its call, U. mimula's call is a "3-5 pulsed signal with a pulse repetition rate off 75.9 sec and a dominant frequency of 2816hz" (Davies et al 1986).

The actual structure of the call is closest to U. altissima. It has been described as a 'click' or an 'explosive tick'. As with all frog calls words are really inadequate and becoming familiar with this call by listening, is an easier way to learn to identify it.

Biology/physiology

(Brodie Jnr et al.,1998 ; Davies et al., 1986)

Morphologically this genus is diverse.The distalate capula in U. mimula are closely applied, a feature that is shared with 5 out of the 23 members of the genus, in the other members they are either fused or free.

U.mimula keys out from the other genus members by the hypertrophied state of the inguinal, parotoid and coccygeal glands. The appearance and use of these glands may be seasonal as in other members of the genus. Males have non-pigmented nuptual pads.

A white flocculent secrection is released from the glands of all members of this genus when they are caught. It contains noxious and toxic organic chemicals including polypeptides,serotonin and alkaloids.The active ingredients of the polypeptides include chemicals which produce smells.

Typical breeding habitat for this species on Magnetic Island

Habitat, Ecology and Behaviour

(Barker et al., 1995, Brodie Jnr et al,.1998, Davies et al.,1986, Cameron and Cogger,1994)

This ecology and behaviour of this species is little represented in the literature. In areas where it is present that have been studied, it is not present in all 'frog calling' areas, presumably restricting itself to areas where specific conditions suit. In the Weipa area it is present at only 11% of sites and a similar percentage on Magnetic Island. When calling on Magnetic Island it shares temporary wetland areas that are predominated by calls of Litoria rothii, Litoria rubella, and Bufo marinus.

This species, along with others of the genus spends much time buried, especially in the dry season and is cryptic except when calling which only occurs after rain.

Uperoleia mimula is mostly found in open forest, paperbark woodland, and gallery forest but it is also known from suburban areas and regenerated areas.

Threat responses to predators of this genus include the exposure of the red skin patches found in the usually hidden groin and femoral areas as well as the release of chemicals from the skin as mentioned previously.

Reproduction

Barker et al., 1995, Cameron and Cogger, 1992,Davies and McDonald, 1998, Frith and Frith1995, Richards and Alford in Davies and McDonald 1998

As in many wet/dry tropics frogs calling is dependant on the rainy season and may commence as soon as water accumulates. Prospective amplicant males call from hiding places beneath leaf litter or vegetation sometimes a little away from the water (<12m). In Cape York U.mimula is known to breed in temporary waters and flooded grassy areas. On Magnetic Is. where there is no permanent water it is known to breed in seasonal still water in isolated paperbark areas. During amplexus, eggs will be laid in small clumps at the edge of (often temporary) pools. A tooth row formula of 2 (2)/3 is found in tadpoles of this species and the oral disc is very small. A dark tail is present in early stages of tadpole development. Tadpoles may reach a size of 20mm.

Barker, J,Grigg, G. and Tyler, M.(1995) A Field Guide to Australian Frogs: Surrey, Beatty and Sons, NSW. Cogger, H. G., 1988. "Reptiles and Amphibians of Australia ". Reed Books, N.S.W

Brodie Jr.,E., Williams, C. and Tyler, M., (1998), Evolution of Aposematic Behaviour and Colouration in the Australian Frog Genus Uperoleia. Journal of Herpetology,: 32: 1: 136-139.

Cameron, E.E. and Cogger, H.G.,(1992) The Herpetofauna of the Weipa
Region, Cape York Peninsula;Technical Report Number 7, Australian Museum.

Davies, M., and McDonald (1998), Developmental Biology of Uperoleia Altissima (Anura Myobatrachidae), Transactions of the Royal Society of S. Aust.,:122(4): 167-172.

Davies, M., McDonald K.R., and Corben, C.. (1986), The Genus Uperoleia Gray ( Anura Leptodactylidae) in Queensland, Australia, Proc. R. Soc. Vict., :98:4:147-188.

Davies, M., Watson, G., Mc Donald, K.R. Trenerry, M.P., and Werren, Garry,(1993), A New Species of Uperoleia ( Anura Leptodactylidae: Myobatrachinae) from Northeastern Australia, Memoirs of the Queensland Museum,:33(1):167-174.

Frith, D. and Frith, C.(1995) Cape York Peninsula - A Natural History, Reed Books, Australia.

Tyler, M., Davies, M. and Martin, A.,(1980), Australian Frogs of the Lepodactylid Genus Uperoleia Gray., Aust. J. Zool., Suppl. Ser.,:79: 1-64.

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