Taudactylus diurnus

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Kingdom Animalia

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Phylum Chordata 
Class Amphibia
Order Anura
Family Myobatrachidae
Genus Taudactylus
Species Taudactylus diurnus
Authority Straughan & Lee, 1966
 
English Name Southern Day Frog, Mount Glorious Day Frog, Mount Glorious Torrent Frog
Dutch Name Mount Glorious-beekkikker
Italian Name Rana Diurna
 
Characteristics The colour of this small frog’s dorsal surface was grey or brown with darker mottling. A dark, irregular, slightly raised H-shaped mark is present over the shoulders, and an irregular pale patch may be present over the pelvic region. This frog has a pale bar between the eyes, bordered behind by a dark brown patch. Short dark stripes run down from the eye to the base of the forearm, sometimes with a pale band bordering the lower edge. Their limbs have irregular dark cross bands. This frog’s ventral surface is cream, yellowish-white or blue-grey, with or without grey spots. Their throat is more heavily spotted or mottled with grey, sometimes with grey with yellow spots. The skin of the southern day frog is smooth, finely granular, or with a few low warts above, but smooth below. This species’ digits have wedge-shaped discs and are unwebbed, but the toes have broad fringes. The males of this frog have a length of 22.0-27.2mm, and the females have a length of 23.3-30.6mm. The southern day frog is lacking vocal sacs, but a call is emitted and resembles a soft chuckling. This call is repeated 1-2 or 4-5 times in quick succession every 4-5 minutes. The tadpoles were of moderate size, with an umbrella-shaped lip, with the labial papillae completely surrounding the labium. There were no labial teeth.
 
Lifestyle The southern day frog was a diurnal species. Activity began at sunrise and ceased soon after sunset, with peak activity occurring at full light. This frog is generally very active, but will sit motionless for periods while basking in sunlit patches or on warm rocks. Individuals frequently entered the water, swimming from point to point or sitting half-submerged. Individuals escape danger by leaping into the water and swimming away, or hiding on the bottom among rocks or loose mud. At night they shelter under rocks and debris or within crevices. The species activity appeared to be restricted by temperature, and this frog was intolerant of desiccation. These frogs remained close to the water (0-10m), because they were fairly intolerant of dry conditions and must frequently enter the water to rehydrate.
 
Range & Habitat The southern day frog was the southern-most representative of the genus. It occurred in disjunctive populations in three sub coastal mountain ranges (Blackall, Conondale, and D’Aguilar Ranges) in the south-eastern Queensland region from Coonoon Gibber Creek in the north to Mount Glorious in the south, near Brisbane. This frog occurred over a relatively narrow altitudinal range of 350-800 m with most records falling between 500-800 m. The extent of its occurrence was about 1400 km2.

This species inhabited montane rainforest, tall open forest and other riparian vegetation with a closed under storey along permanent and temporary streams. It prefers permanent streams with a rocky substrate, but used streams with a wide variety of substrates provided the water is not very muddy. Active frogs could be found among low vegetation, rocks, leaf litter and other debris. Generally they were found within 10m of water, although they have been recorded about 22m from water in wet weather.
 
Food Southern day frogs have been observed in the wild taking small insects along or near streams. There have been no observations to suggest that prey was taken from the water. Analysis of the gut content (Straughan & Lee, 1966) showed that these frogs to be opportunistic feeders of invertebrates from the forest floor. Amphipods, hymenopterans and lepidopteran larvae were the most commonly recorded prey in the researched sample. The tadpoles were bottom dwellers, feeding by scraping food from the substrate.
 
Reproduction Active southern day frogs have been observed all year round, although less frequently during cooler winter months. Breeding occurred in warm weather after or during heavy rain between October and May, peaking in January to March. The amplexus is inguinal and the eggs are deposited in gelatinous clumps under rocks or branches in water. (Amplexus is the process when the male frog grasps the female while she lays her eggs. At the same time, he fertilizes them with the fluid containing sperm.) The tadpoles could be found year round.
 
History & Population Straughan and Lee described this frog in 1966. It was considered to be relatively common where it occurred in the early 1970s. However, the species declined rapidly after that. The disappearance of the southern day frog occurred over a period of three to four years. This frog disappeared from the D’Aguilar Range in late 1975, then from the Blackall Range in late 1978, and finally from the Conondale Range in early 1979. This frog has not been sighted since 1979 despite continued efforts to relocate the species. There is no information on population size, structure, genetics or dynamics.
 
Extinction Causes The reason(s) for the disappearance of this species remains unknown. The scientists Tyler and Davies (1985) found no obvious evidence that over-collecting, pollution from logging or gold panning, or drought was responsible for the population decline of the closely associated southern gastric-brooding frog (Rheobatrachus silus). Like the southern gastric-brooding frog (Rheobatrachus silus), logging has occurred in catchments occupied by the southern day frog. However, the effect of timber harvesting on the species has not been investigated. Ingram (1990) argued that the disappearances might be due to late rains falling in the cooler months (climate change). Current research is examining the possibility that a disease may have caused the decline of this species. The frog’s habitat was and is currently threatened by feral pigs, the invasion of weeds (especially mistflower Ageratina riparia), and altered flow and water quality due to upstream disturbances. The southern day frog was not found in areas along watercourses that were heavily infested with Lantana camara, or where the weeds Baccharis halimifilia and Ageratina riparia (mistflower) occurred. These frogs were also absent from streams with very muddy water associated with the activities of feral pigs.

New information from: Queensland Museum - Why are our frogs disappearing? In 1993, two leading Queensland researchers (Glen Ingram, then of the Queensland Museum and Keith McDonald of the then Department of Environment) wrote: "In Queensland since 1978, seven species of frogs have disappeared and populations of another four have seriously declined. All the declines have occurred in upland rainforest and all the species live along or breed in streams. We ask the question "what is wrong with upland rainforest streams" and answer "nobody knows". We note the 14 years elapsed from the time of the first disappearance in 1979 until intensive research began into the cause, or causes, of the declines. We ask "why" and conclude that the reasons were scepticism and a lack of interest in the plight of frogs. Finally we appeal for thought: there appear to be many clues to the solution of the problem of the declines." 

In October 1999, the situation has changed. After many years of painstakingly detailed field monitoring, breeding/ maintenance in captivity experiments and pathology testing, three likely causes for these declines have emerged. The first may be global warming. The second appears to be a micro-organism, a 'fungus' (Phylum Chytridiomycota of the Kingdom Protoctista). The third is undoubtedly people-related habitat destruction and degradation. All may be linked.

This problem is of major concern to everyone passionate about conservation of biodiversity. It is not confined to Queensland or Australia. Similar declines have been reported in North and South America, Europe, and South Africa, all areas where there are active biological research communities. In areas such as south east Asia and New Guinea, where monitoring has not been possible, no one can say whether or not frog populations are secure.

Nearly 20 years after this problem was first reported, a picture is emerging of why it has occurred. Yet to be determined, however, is the full-extent of the problem. Most critical is finding out what can be done to combat it and to find missing species or restore those nearly lost.
 
Conservation Attempts Its habitat is protected within National Parks (D’Aguilar, Conondale Range, and Kondalilla Falls). A recovery plan has been prepared and searches continue. Sadly enough this all could not prevent its disappearance and the species is still not rediscovered.
 
Museum Specimens The Australian Museum has a specimen of the southern day frog, see Australian Museum Collections - Herpetology Collection Gallery - Southern Day Frog. Please email me with more information on museum specimens.
 
Relatives Relatives of the southern day frog are the: Sharp-snouted Day Frog (Taudactylus acutirostris); Eungella Day Frog (Taudactylus eungellensis); Eungella Tinker Frog (Taudactylus liemi); Kroombit Tinker Frog (Taudactylus pleione); Northern Tinker Frog (Taudactylus rheophilus).
 
Links

IUCN Red List of Threatened Species - Taudactylus diurnus.

AmphibiaWeb - Southern Day Frog.

Southern dayfrog - EPA/QPWS

Australian Museum Collections - Herpetology - Australia's Lost Frogs.

Australian Museum Collections - Herpetology Collection Gallery - Southern Day Frog.

Queensland Museum - Why are our frogs disappearing?

Last updated: 18th July 2004.

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