Research

Two species of New Caledonian lizards endemic to maquis shrubland –Maruia Maquis Skink Lioscincus maruia and Tillier’s Maquis Skink Lioscincus tillieri

Introduction
Terms
The Maquis Skinks
Acknowledgements
References

Chutes de Madelaine on the Plaine des Lacs, a region with an extensive cover of maquis shrubland in the south of New Caledonia.

Distribution of vegetation in New Caledonia (from Atlas de Nouvelle Caledonie). The distribution of maquis shrubland (dark orange) can clearly been seen extending over much of the southern third of the island, and as isolated patches along the central east coast and north-west coast.

Bikkea, one of the many unusual plants endemic to maquis shrubland.

Introduction

The maquis shrubland vegetation of New Caledonia is a characteristic low and heath-like. It is largely restricted to ultramafic substrates at various altitudes on the main island. It covers around 30% (4,500 km) of the territory and characteristic of much of the southern ultramafic region of New Caledonia. The flora of maquis shrubland on New Caledonia's ultramafic substrates is rich in species and with a very high degree of endemism. This is one of the factors in recognising New Caledonia as one of the world’s top ten biodiversity 'hotspots'.

Field research on New Caledonian reptile fauna has concentrated on closed-forest habitat, which has the greatest diversity and richness of lizard species. Survey work in closed forests has found around 15 to 17 species, or approximately 20-30% of the island’s total lizard fauna. By contrast the reptile fauna of maquis shrubland, has been poorly studied.

However, opportunistic collections made in maquis habitat suggest this vegetation type while not rich in total number of lizard species contains several that are largely dependent upon, or endemic to it. Among the lizard species that appear to be restricted to this habitat type are two species of skink, Tillier’s Maquis Skink Lioscincus tillieri and the Maruia Maquis Skink Lioscincus maruia, both of which have only been described in recent times.

Terms

Maquis shrubland - low and heath-like vegetation
Ultramafic - rocks that are dominated by minerals high in magnesium and iron, and which tend to be dark-coloured rather than pale.
Endemism - species that are native to a particular geographic area.

An adult male Tillier’s Maquis Skink Lioscincus tillieri.

An adult male Maruia Maquis Skink Lioscincus maruia.

The Maquis Skinks

Lioscincus tillieri appears to be endemic to maquis habitat in the ultramafic block that covers much of the southern third of the island and occurs over a broad latitudinal range from 200-1000 m elevation. Lioscincus maruia occurs in maquis habitat north of the southern ultramafic block from Me Adeo in the central ranges to Plateau Tia on the northwest coast.

Distribution of Lioscincus maruia (squares) and Lioscincus tillieri (circles) in the New Caledonian region.

Maquis shrubland at Me Adeo in the central ranges, the locality from which Lioscincus maruia was originally recorded.

In overall morphology Lioscincus tillieri and Lioscincus maruia are very similar in body proportions (long-limbed and long-tailed), habits and habitats (surface active species inhabiting maquis shrubland), and in certain aspects of scalation (keeled body scales), osteology (58 or more postsacral vertebrae), and colouration (yellow flush to the ventral surface). One of the major differences between the species is that Lioscincus tillieri is a live-bearing species (one of only two New Caledonian skinks) whereas Lioscincus maruia is egg-laying.

Threats to maquis habitat, clearing of mid to high elevation habitat for mining.

Lioscincus tillieri is known from six locations in the south of the island and is not considered to be rare; it would not be regarded as threatened under the current IUCN (International Union for the Conservation of Nature and Natural Resources) classification system (1996). Lioscincus maruia is known from fewer locations but these are widely spread over maquis habitat in the central ranges and ranges along the northwest coast, and is expected to be found in other locations within that range.

Our field research clearly indicates that both species are dependent upon maquis habitat, however, it is not known whether any particular succession stage of maquis is preferred by either species. Consequently the impact of fire and disturbance by mining on maquis habitat are unknown but could be significant and impact on populations of either species at a local level.

Acknowledgements

We thank the New Caledonian authorities for permission to collect and conduct research in New Caledonia . Funding for field research provided by the French Ministere des Affaires Etrangeres, and through the Province Nord Biodiversity Project which was initiated and funded by Conservation International (Washington DC), the Maruia Society (New Zealand), and Province Nord (New Caledonia). We particularly wish to thank Jean Chazeau of ORSTOM Centre de Noumèa for his support and encouragement of our reptile research in the region.

References

Bauer, A.M. and R.A. Sadlier. 1993. Systematics, biogeography and conservation of the lizards of New Caledonia. Biodiversity Letters 1: 107-122.
Ineich, I. and R.A. Sadlier. 1991. A new species of scincid lizard from New Caledonia (Reptilia Lacertilia Scincidae). In : Zoologica Neocaledonica, Volume 2. Memoires du Museum National d’Histoire Naturelle, (A), 149 : 3434-347.
International Union for the Conservation of Nature and Natural Resources, 1996. IUCN Red List of Threatened Animals. IUCN, Gland , Switzerland.
Sadlier, R.A. 1986. A review of the scincid lizards of New Caledonia. Records of the Australian Museum 39(1): 1-66.
Sadlier, R.A., A.H. Whitaker and A.M. Bauer. 1998. Lioscincus maruia, a new species of lizard (Reptilia: Scincidae) from New Caledonia, southwest Pacific. Pacific Science 52(4): 334-41.