REPTILES

Springbrook is a refugium for relict reptiles of the most ancient lineages of tortoises, lizards and snakes considered to be basal amongst the world’s reptiles and which have evolved in East Gondwana. Reptiles exemplify major stages in the earth’s evolutionary history including ancestral and more recent major radiations in the Mid-Miocene associated with global cooling in the Cenozoic and the Plio/Pleistocene, the last Ice Ages. They were once one of the most successful evolutionary radiations and still represent one of the most diverse vertebrate groups alive on earth today. They thus contribute significantly to the Outstanding Universal Value of the Gondwana Rainforests of Australia World Heritage Area. Consideration of their critical habitat and landscape integrity requirements is important for the success of the restoration program associated with Springbrook Rescue.

Reptiles evolved from early amphibians as far back as 220 Ma and, because they overcame a dependence on water compared with most amphibians, came to dominate every corner of the earth during the Age of the Dinosaurs. Most, however, became extinct at the end of the Mesozoic Era. Only four major groups are recognized today, three of which occur in Australia — turtles and tortoises (order Testudines), snakes and lizards (order Squamata), and crocodiles (order Crocodilia). The fourth group comprises an ancient group whose sole living representative is the lizard-like Tuatara of New Zealand. Only Testudines (turtles and tortoises) and Squamata (snakes and lizards) are represented at Springbrook. It has generally been accepted that chelid turtles, the diplodactyline geckos, the endemic family Pygopodidae (legless or flap-footed lizards) and agamid lizards have had a long history in Australia (Heatwole 1987).
TURTLES

Wollumbinia latisternum Photo: Stewart Macdonald

The earliest turtles date from 215 million years ago in the Triassic Period and as such are one of the oldest reptile groups, more ancient than lizards, snakes and crocodiles. There are 328 species of turtles (Testudines) present in the world today (The Reptile Database, 2012). There are 263 species of freshwater and terrestrial turtles but only 58 species of tortoises, and 7 sea turtles. 

Turtles and tortoises are now the most endangered group of vertebrate animals, with more than half of their 328 species threatened with extinction.
Experts consider this as one of the most significant wildlife crises of our time. With more than 54 percent threatened this extinction crisis is greater than for any other vertebrate group such as birds (12%), mammals (23%), sharks and rays or even amphibians (32%) (www.edgeofexistence.org, 2012).

One view is that modern turtles worldwide evolved from the Chelidae, a ‘primitive’ side-necked turtle group unique to Australia and South America. The Chelidae is known to comprise 52 species (The Reptile Database, November 2012).

One member of the Chelidae is present at Springbrook — the Saw-shelled Turtle, endemic to Australia, found mainly in Queensland, with range extensions into New South Wales and the Northern Territory. It was renamed by Richard Wells in 2007, as Wollumbinia latisternum after Wollumbin (‘cloud catcher’), the Bundjalung people’s name for Mount Warning in the centre of the Tweed caldera. This is a significant area in the evolutionary history of this group of turtles. W. latisternum prefers sheltered, deeper waters under banks or under submerged logs and rocks in second or third order streams rather than major river courses. It is mainly diurnal but may bask during the day on exposed rocks and logs. Despite being territorial they retreat, sometimes in large numbers, to isolated water holes if their habitat becomes seasonally dry. It is carnivorous, consuming frogs, small fish, invertebrates and carrion.
SNAKES AND LIZARDS (squamates)

The earliest squamates (scaled reptiles) were the limbless dibamids and geckos which appeared more than 200 million years ago. These two groups together are sister to all other squamates (Wiens et al. 2012).

The Order Squamata classically comprises three suborders:
            Lacertilia - the lizards (5600 species in 101 genera, 13 families)
            Serpentes - the snakes (3400 species in 500 genera and 20 families)
            Amphisbaenia - the worm lizards (over 130 species in 4 families)

Snakes and lizards together (over 9,000 species in 61 families) make up nearly 95% of the world’s known species of modern reptiles (over 9,500 species).

Of the world’s total of 5600 lizards, 723 species occur in Australia, 335 (46.3%) of these being found in Queensland. This is the second highest diversity in Australia after Western Australia (379 species). Generic diversity is highest in Queensland. There are seven families: the dragons, monitors, skinks, flap-footed lizards and three families of geckos (Wilson 2012).

Springbrook, despite its small size, is home to 33 lizards or 10% of the total found in Queensland. These include:

Geckos                            4 species in 4 genera within 2 families

Flap-footed lizards        2 species in 2 genera within the Pygopodidae

Dragons                          4 species in 4 genera with the Agamidae family

Monitors/Goannas        1 species – the Lace Monitor

Skinks                             22 species, in 14 genera c.f. 39 genera in Australia, 32 in Queensland)

GECKOS

Geckos (infraorder Gekkota) are among the most species-rich and geographically widespread of all terrestrial vertebrate lineages with ~1450 described species in 118 genera and seven families comprising 25% of all described lizard species (Gamble et al. 2012).

Their success has been linked to traits such as nocturnality, visual and olfactory prey detection and the adhesive toe pads found in 60% of all geckos (in Gamble et al. 2012). They are evolutionarily extremely significant. Together with limbless dibamids, they are the sister group to all other lizards and snakes (i.e. the limbless dibamids have their greatest surviving diversity in the nearby region of New Guinea, an old part of Australia). They are thought to have diverged 225–180 million years ago.

Australia’s gecko fauna is exceptionally rich (>160 species), highly endemic and morphorlogically diverse (Wilson and Swan 2010). Of the four deeply divergent gecko lineages present, only the family Gekkonidae is widespread outside the Australasian region — the three remaining Australian families of geckos (Carphodactylidae, Pygopodidae and Diplodactylidae) are part of an ancient East Gondwana radiation originating in the Late Cretaceous (Gamble et al. 2008; Oliver and Sanders 2009).

The most basal family is the Carphodactylidae, followed by the Pygopodidae and Diplodactylidae (Wiens et al. 2012). Later evolving families such as Eublepharidae, Sphaerodactylidae and Phyllodactylidae do not occur in Australia. The Gekkonidae and Sphaerodactylidae are sister groups.

Carphodactylidae (29/29) Leaftail and knobtail geckos

Twenty-nine species within six genera are endemic to Australia: Saltuarius (6), Phyllurus (9), Carphodactylus (1), Uvidicolus (1), Underwoodisaurus (2), and Nephrurus (9).

The family exemplifies adaptation from ancestral rainforests to the increasing aridity following Australia’s separation from Antarctica. Over half the species diversity and most of the generic diversity (Saltuarius, Phyllurus, Orraya and Carphodactylus) are confined to rainforest or mesic niches, the ancestral aseasonal wet habitat (Couper et al. 2008, Oliver and Bauer 2011). They are arboreal or saxicolous with specialized adaptations such as robust decurved claws and a depressed body.

Saltuarius appears to be basal within the family.

 Other genera Uvidicolus, Underwoodisaurus and Nephrurus (knob-tails) are all terrestrial lizards reflecting adaptations to the expanding arid environments in Australia during the Miocene. Terrestrial niches outside rainforests are more abundant and not as vulnerable to dessication as are arboreal niches. The function of their bizarre knob tail, once though to relate to energy storage, remains an enduring mystery (Oliver and Bauer 2011).

The Southern Leaf-tailed Gecko (Saltuarius swaini), one of six oviparous species in the genus Saltuarius, is narrowly restricted to the Tweed Caldera area. It is not found in the Conondale, Blackall and D’Aguilar Ranges of South-east Queensland despite suitable habitat (Low 2011). Rainforest in these blocks contracted during arid glacials and taxa such as the leaftails failed to recolonise because of inhospitable intervening habitat Couper et al. 2008). The sister taxon Carphodactyus laevis, the sole surviving species in its genus, is restricted to the Wet Tropics of Queensland World Heritage Area.

Saltuarius swaini Southern Leaf-tailed Gecko. A small genus and member of the East Gondwanan Carphodactylidae
family that is basal to all lizards and snakes, now restricted to the moist upland rainforests of the McPherson Range.
The species diverged from a common ancestor at least 50 Ma (Mulcahy et al. 2012). Photo: Ken O’Shea 30/9/2008

Pygopodidae(Legless Lizards, snake-lizards or flap-footed lizards)

The Pygopodidae is a family of squamates closely related to geckos, sometimes referred to as pygopod geckos. Because of their long, slender, bodies resembling snakes, they are also referred to as snake-lizards. However, unlike snakes, they have vestigial hind limbs resembling flattened flaps and can vocalize. Some can hear high-pitched sounds above 11,000 Hz which snakes cannot. The Pygopodidae are endemic to Australia and New Guinea. Whilst the group originated at least 40 million years ago the vast majority of living pygopodids arose in the last 23 million years associated with the drying of the continent (Jennings et al. 2003). Fossils of Pygopus similar to Pygopus lepidopodus (Common Scaly-foot) have been found at Riversleigh in NW Queensland dating to 20–23 Ma during the early Miocene (Hutchinson 1997).

There are at least 35 species in two subfamilies and eight genera.

Diplodactylidae

The family of 126 species is restricted to the East Gondwanan fragments of Australia, New Caledonia and New Zealand. There are 79 species in seven genera within Australia: Crenadactylus (1/1), Pseudothecadactylus (3/3), Rhynchoedura (6/6), Lucasium (11/11), Diplodactylus (18/18), Oedura (15/15), and Strophurus (17/17). There are five deeply separated groupings (clades) revealed in phylogenetic studies. Crenadactylus is basalmost but Diplodactylus is basal to the group which includes Oedura and Strophurus.

Diplodactylus vittatus Eastern Stone Gecko is considered basal within the genus of 18 species and is common throughout south-eastern Australia, and occurs at Springbrook in dry sclerophyll forests, hiding under small surface objects, in burrows or soil cracks. At night they emerge and are often found on low perches of stones or small fallen branches.

Recent genetic studies indicate great cryptic diversity so that the actual number of species within just the Diplodactylus genus is likely to be double that currently recognized (Oliver et al. 2001). It is also possible that a more basal taxon associated with ancestral rainforest is extinct.


Gekkonidae (917 species worldwide in 51 genera)

There are 141 Australian species of Gekkonidae in 21 genera including: Christinus (2/2), Cyrtodactylus (135/7), Gehyra (36/20), Hemidactylus (90/1), Heteronotia (3/3), Lepidodactylus (33/3), and Nactus (12/4)

The highest diversity is in Queensland (57 species) and Western Australia (60 species). The Gekkonidae are represented in Springbrook by two species in two widely distributed genera:

Gehyra dubia Dtella (one of 20 species in the genus)
Heteronotia binoei Bynoe’s Gecko (one of 3 species in the genus, inhabiting dry open habitats and common throughout Australia)

Gehyra (36 species worldwide; 20 species in Australia) is rare among squamate radiations in spanning continents from south-east Asia to Australia and Polynesia. Gehyra is the only genus within the family that is the most species rich within Australia (Heinicke et al. 2011). If extinctions are taken into account, there is a strong possibility that the genus, like the Pygopodidae, is Gondwanan given the earliest Australian species date to at least 56 Ma, long before the final breakup of Gondwana and, in particular, collision with the Asian plate (Byrne et al. 2011).
DRAGONS

The Agamids belong to the suborder Iguania, a diverse group of lizards with  ~1,600 named extant species or ~18% of all squamates (Uetz 2010). They inhabit a wide range of warm environments from deserts to tropical rainforests. Distinctively among lizards, their teeth are borne on the outer rim of the mouth (acrodont) compared with the inner side of the jaws (pleurodont). The Acrodonta are basal; the Pleurodonta are more recently evolved.

The Agamidae family (Agamids) includes more than 300 species in Africa, Asia, Australia and a small number in Southern Europe. Six subfamilies are recognized

Lophosaurus spinipes: a baby Southern Angle-headed Dragon (Ken O’Shea 21/9/2009)

Young Water Dragon Physignathus lesueurii
MONITORS

The Varanidae family (monitors) is an ancient group of anguinomorph lizards with about 50-60 species in the sole genus Varanus. About half of all living species are found in Australia. At least ten subgenera of Varanus are recognized, two of which (Varanus and Odatria) contain the most species. Subgenus Varanus includes the large-bodied Australian and Indonesian taxa. Subgenus Odatria includes the small-bodied Australian endemic taxa.

Varanus varius Lace Monitor on Ankida Photo: Aila Keto

References

Fry, B.G., Vidal, N., Normal, J.A., Vonk, F.J., Scheib, H., Ramjan, S.F.R., Kuruppu, S., Fung, K., Blair Hedges, S., Richardson, M.K., Hodgson, W.C., Ignjatovic, V., Summerhayes, R. and Kochva, E. (2006). Early evolution of the venom system in lizards and snakes. Nature 439, 584-588.

Hutchinson, M.N. (1997). The first fossil pygopod (Squamata, Gekkota), and a review of mandibular variation in living species. Memoirs of the Queensland Museum 41, 355-366.