Taxonomy

( Frith, 1987; Hutchison and Maxon, 1986; Tyler and Davies, 1978; Tyler et al., 1994;

The common name of 'rocket ' frog is drawn from the aerodynamic shape (described by Tyler as ' aerodynamic perfection') and the Latin species name translates as 'large-nosed'.

Litoria Nasuta and Litoria freycineti were assigned to a species group of their own in 1978, based on a mostly morphological basis entitled the Freycineti Group after the earlier described species. Later Immunilogical approches to phylogeny within Litoria, show immunilogical distances between L. nasuta and L. latopalmata to be almost as close as L. frycineti and the distance between L. freycineti and L. latopalmata to being even closer, suggesting that the boundaries of the original species group placement may need readjusting.This study places L.freycineti and L. latopalmata as purportedly having a common ancestor apx. 2 million years ago with both having split from L. nasuta around 5 million years ago. It names all three the Litoria freycineti Complex and says that along with L. ewingi there may have been a separate lineage from other Litoria since the beginning of the Miocene.

Description

(Barker et al.1995; Cameron and Cogger 1992; Cogger, 1988; McDonald, 2000; Tyler, 1976; Tyler and Davies 1978, Tyler et al., 1994.)

Litoria nasuta is a small to medium sized streamlined, long-legged, striped, terrestrial frog with small finger and toe disks and a wedge-shaped head. A broad vertebral band of light brown usually extends along the entire dorsal surface but the colour and pattern of this species may vary. On either side of this there may be a series of darkish brown patches, with broad darker bands bordering them.The tympanum is easily seen and edged with white. Laterally, from the nares to the base of the forelimb, there is a dark stripe broken in the eye area by a light band in the front of the eye. From below the eye to the base of forelimb, there is a light glandular stripe .

Color of the limbs is variegated and has dark, broken banding. The Ventral surface is pale or whitish and granular. There are numerous tubercles present on the back with skin folds running along the length. The posterior of the thigh area has horizontal banding made up of dark brown spots on a yellowish field. There is no webbing on the fingers and the toes are half –webbed, with the forth being free for 3/4 of its length. Between the choanae there are well-developed vomerine teeth. The metatarsal tubicle on the outside has uneven edges and the inner will be small. Colours intensify in breeding males with the periphery of the jaw area turning black and white and the usually whitish throat area may become covered with tiny dark spots.

Size (snout-vent). Females range between 36-55 mm (apx.) with males smaller, from 33-45mm. (apx.) The average size in North Queensland is said to be 45mm. L. nasuta can be adult from as little as 9mm.

Foraging Adult

Call

( Barker et al., 1995, Cameron and Cogger, 1992; Clyne, 1969; McDonald, 2000; Sawyer and Morris, 2004.)

Several seconds in length, the call is a series of short, punctuated notes that has been described as 'but, but, wick, wick, wick, wick, wick' ; clucks, wecks and clucks or as a 'nasal yapping'. As with all frog calls, becoming familiar with this call by listening, is an easier way to learn to identify it. In the Darwin area males have been heard calling in the afternoon if there has been rain.

Geographic range.

(Barker et al., 1995; Cameron and Cogger, 1992; Cogger,1988, Tyler, 1976; Tyler et al., 1994.)

In some areas, such as Weipa, this frog is the one most abundant of the species present. It ranges from just north of Newcastle up to the tip of Cape York and arcs across the top of the N.T. over to W.A. and south there to Kunnanurra, the Yampi peninsula and Mt Bell. L. nasuta has limited distribution in southern New Guinea and is considered to have crossed over from Australia when a land bridge was in place (apx 6000 years ago).

Biology/physiology

( James, 2007, Tyler and Davies, 1978, Young et al., 2005; Tyler, 1976)

The sizable tubicles under the hands and feet are postulated to be used as a protection for palms and soles.

The hyloid plate bears dilated alary processes and its intercalary structures are elongated and ossified, and are the largest found in the members of the genus. It also possess a SVL to leg length ratio higher than any other recorded in the world (2.02) .

Tests done on the skin secretions of L. nasuta preserved specimens from the Brisbane area showed them to contain an average of 1 micro gram of Caerulean per gram of dried skin.

There appears to be no significant difference in evaporative water loss in this species between the wet and dry seasons in Northern Australia but it is considered to have a low cutaneous resistance to water loss in general.

The diploid chromosomes of this species number 26.

Typical breeding habitat for this species on Magnetic Island

Habitat, Ecology and Behaviour

( Barker et al., 1995; Cameron and Cogger, 1994; Clyne, 1969; Cogger, 1988; Friend and Cellier, 1990; James, 2007; McDonald, 2000, Tracey and Christian, 2005; Tyler et al., 1994; Tyler, 1976)

Litoria nasuta , as its common name suggests, is a skillful and accomplished 'jumper' able to escape very quickly when disturbed. During tests its jumping distance was measured in body lengths as 55.2 which places it second on a world list of measured Anuran jump lengths

A mostly ground-dwelling nocturnal predator, Litoria nasuta can be often found hunting amongst leaf litter where it is superbly camouflaged. The margin of creeks, grasslands and open forest can form its habitat although a preference seems to be shown for permanent grassy swamps. In Kakadu the range of L. nasuta was shown to be widely distributed in both the wet or dry season, except for calling.

Studies of the diet of this species have shown them to feast predominantly on insects and spiders but this may vary with the local environmental conditions and seasonality.

Litoria nasuta has been recorded in the diet of the freshwater Keelback Snake (Tropidonophis mairii). Other predators should include the usual frog predators such as reptiles and birds etc., although with its rapid jumping expertise it may be difficult to catch.

Reproduction.

(Anstis, 2002; Barker et al., 1995; Cameron and Cogger, 1992; Cogger, 1988; Dziminski and Alford, 2005; Lee and Jamieson, 1993; McDonald, 2000; Tyler and Davies, 1978/1991; Tyler et al., 1994; Tyler, 1976)

In Northern Australia male Litoria nasuta will call near temporary waters. Positioning themselves adjacent to and often partially in the water, underneath grasses or other vegetation.

Spring to early autumn is the calling period for Southern populations of L. nasuta and in Northern Australia this corresponds to November through to February depending on the Wet season. The eggs have a white vegetal pole and a black animal one. The egg capsule size is apx. 3.03 -3.69 mm with the eggs themselves 1.0-1.3 mm in diameter. The size and morphology of all Litoria spermatozoa is said to be similar, and although not listed for this species, if this is true, then the spermatozoa body size will be apx.18µm long and the tail 35µm. Researches have found that there is a size difference in the yolks, from this species, within the individual clutches of eggs. Further experiments on the growth of the tadpoles showed that initially smaller yolked individuals will be slower to metamorphosize than those individuals that came from eggs with larger yolks.

The spawn, laid in relatively shallow waters, is variously described as a film and a clump but it seems it is laid as surface film of 50 to 100 small eggs which then will clump when disturbed .Three to four days after laying, hatching will begin.

Tadpoles grow to apx. 56 mm, have a medium sized body shape with an olivey brown appearance, scattered over with tiny iridescent melanophores, when viewed from above and slightly darker below. The head of the tadpole in this species will start to resemble the adult head shape fairly early on in development and a light-coloured mid-dorsal stripe from apx. 3/4 along the body extending down the tail also appears, and is obvious, during the mature stages.The tail fins are arched from a slight to moderate degree and taper to a thin point. The laterally located eyes are ridged above and have a thin border on the pupil, of a copperish hue. They are mainly but not exclusively benthic feeders. Their tooth formula is 2/3 and the teeth are considered long.

Metamorphosis takes a minimum of 31 days apx. at high temperatures (30°C) and up to 53 days in southern areas. It can range from 1-5 months depending on local environmental conditions.

Calling male

References

Anstis, M (2003) Tadpoles of South-eastern Australia, Reed New Holland, Sydney, NSW

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.

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

Clyne, D., (1969) Australian Frogs, Lansdowne Press, Melbourne.

Cogger, H. G., (1988). "Reptiles and Amphibians of Australia ". Reed Books, N.S.W.

Dziminski, M.A. and Alford, Ross A.(2005), Patterns and fitness consequences of intraclutch variation in egg provisioning in tropical Australian frogs, Oecologia 146: 98–109

Frith, D. and Frith C., (1987), Australian Tropical Reptiles and Frogs, Tropical Australia Graphics, Paluma.

Friend, G.R. and Cellier,K.M. (1990) Wetland Herpetofauna of Kakadu National Park, Australia: Seasonal Richness Trends, Habitat Preferences and the Effects of Feral Ungulates, Journal of Tropical Ecology, 6(2):131-152

James, R.,(2007) Explosive jumping: Extreme morphological and
physiological specialisations of Australian Rocket frogs (Litoria nasuta), Abstracts / Comparative Biochemistry and Physiology, Part A 146 S107–S127

Lee, M.S.Y.and Jamieson ,B. G. M.,(1993), The ultrastructure of the spermatozoa of bufonid and hylidfrogs (Anura, Amphibia): implications for phylogeny and fertilization biology, Zoologica Scripta, 22;3, :309-323.

Hutchison, M.N.and Maxon L.R.,(1987) Phylogenetic Relationships among Australian Tree Frogs (Anura : Hylidae : Pelodryadinae): an Immunological Approach, Aust. J. Zool., 35: 61-74.

McDonald, K., (2000), in "Wildlife of Tropical North Queensland" Eds. Ryan, M. & Burwood,.C.Pp.170-195 :Queensland Museum.

Sawyer, G and Morris, I., (2004), Survey Report on Frog Fauna in the Darwin Wharf Precinct; Technical Report prepared for the Draft Environmental Impact Statement for the Darwin City Waterfront Redevelopment

Swan, G.,(2001) Frogs of Australia,New Holland Publishers, Melbourne

Tracey, C.R., Christian, K.A. (2005)Preferred Temperature Correlates with Evaporative Water Loss in Hylid Frogs from Northern Australia, Physiological and Biochemical Zoology 78(5):839-846 2005 University of Chicago

Tyler M.J., (1994), Australian Frogs - A Natural History,Reed Books, Chatsworth, NSW.

Tyler M.J.and Davies, M. (1978)Species-groups within the Australopapuan Hylid Frog
Genus Eitovia Tschudi: Australian Journal of Zoology Supplementary Series No. 63 C.S.I.R.O

Tyler M.J.and Davies, M. (1986), Frogs of the Northern Territory, For the Conservation Commision of the Northern Territory by the University of Adelaide.

Tyler, M.J. & Davies, M. (1992) Family Hylidae, Fauna of Australia Series - Australian Government Publication, C.S.I.R.O., Australia

Tyler, M.J., Smith, L.H. and Johnstone, R.E. (1994), Frogs of Western Australia, W.A. Museum, Perth.

Young, J.E., Christian, K.A., Donnellan, S., Tracey, C.R.and Parry, D. Comparitive analysis of Cutaneous Evaporative Water Loss in Frogs, Physiological and Biochemical Zoology, 78(5):847-856 2005 University of Chicago

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All photographs and audio taken by author unless otherwise captioned.