Research

The discovery and description of two new species restricted to high altitude forest in the Province Sud – The Red-tailed Shiny Skink Sigaloseps ruficauda and the Montane Marble-throated Skink Marmorosphax montana

Introduction
Terms
Conservation status
Acknowledgements
References

Introduction

The scincid (skink) lizard fauna of New Caledonia is extremely rich and diverse. Field research in recent times has resulted in the discovery of a number of new taxa. The south of New Caledonia , characterised by the extensive ultramafic block that covers much of the south of the island, contains a suite of taxa restricted to that region. Field research in 1995 at Mt Mou and Mt Ouin in southern New Caledonia resulted in the discovery of two new species of skink, The Red-tailed Shiny Skink Sigaloseps ruficauda and the Montane Marble-throated Skink Marmorosphax montana, in high altitude habitats.

The Red-tailed Shiny Skink Sigaloseps ruficauda from Mt Mou.

The Montane Marble-throated Skink Marmorosphax montana from Mt Ouin.

Sigaloseps ruficauda is known only from low closed forest near the summit of Mt Ouin and maquis shrubland adjacent to low closed forest near the summit of Mt Mou. On Mt Mou the high altitude maquis shrubland has a dense understorey of ferns, Sigaloseps ruficauda was collected among the jumbled rocks covered by the understorey.

Distribution of Sigaloseps ruficauda and Marmorosphax montana in southern New Caledonia.

High elevation closed forest habitat and adjacent maquis shrubland habitat for Marmorosphax montana.

Marmorosphax montana was discovered in closed mountain forest habitat between 900-1100 m on Mt Ouin in the south of New Caledonia . Three specimens were located under piles of fallen rocks and wet earth at the edge of a track cutting through forest near the summit, and one from beneath a rock on an overgrown track adjacent to hillside forest at approximately 900 m above sea level.

High elevation maquis shrubland on Mt Mou, habitat for Sigaloseps ruficauda.

Both species are likely to occur only as scattered relic populations in suitably moist habitats around 1000 m in altitude.

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.

Conservation status

Because of their apparently restricted distribution and habitat preference Sigaloseps ruficauda and Marmorosphax montana are both considered to be of particular conservation concern.

Mining activity on the mid to upper slopes of the New Caledonian ranges is most prevalent in the central ranges of the island and on isolated peaks on the west coast. Mining at high altitude in the southern New Caledonia is at present limited, although the small patch of high elevation forest at Mt Ouin is traversed by numerous tracks along its flanks and near the ridgetop, presumably to facilitate mining exploration. Should mining activity be extended to this area or other areas where Sigaloseps ruficauda and Marmorosphax montana are likely to occur, it could have a marked negative impact upon on these and other reptile species restricted to high altitude habitat in the region.

Track to Mt Ouin.

Mid elevation maquis shrubland on Mt Mou. This habitat has a fire history of repeated burning and is now simplified in structure and dominated by a fern understorey.

Neither of the known populations of Sigaloseps ruficauda or of Marmorosphax montana are currently protected within a fauna reserve. Although the population of Sigaloseps ruficauda on Mt Mou is within the Mont Mou Reserve Speciale Minieres et Botanique where collection and disturbance of minerals and vegetation in this reserve is prohibited. This affords some protection to habitat within the reserve.

Because of the restricted nature of their distribution and apparently restricted habitat preferences both Sigaloseps ruficauda and Marmorosphax montana could conservatively be regarded as Vulnerable:D2 under the current IUCN (International Union for the Conservation of Nature and Natural Resources) (1996) classification system (D2 = very small population or very restricted distribution; population is susceptible; area of occupancy <100 km2 or number of locations <5). When the fragmented nature of their respective distributions is also taken into account, any human activity in the region that could threaten the preferred habitat of either species would place that species in a higher category of risk. A further consideration is its occurrence outside designated fauna reserves.

Field research to further determine the distribution and habitat preferences (particularly the extent of its reliance upon high altitude maquis habitat) of both species are urgently required to fully determine their conservation status and the potential impact of development.

Glenn Shea on track to summit of Mt Mou.

Nickel mining in maquis shrubland.

Acknowledgements

The authors thank the New Caledonian authorities for permission to collect and conduct research in Province Sud, particularly Monsieur M. Boulet, former Chef du Service de l'Environnement et de la Gestion des Parcs et Reserves. Logistical support and encouragement was provided by Jean Chazeau of Centre ORSTOM Noumèa. Funding for field research which included the first visit to Mt Ouin was provided by the French Ministëre des Affaires trangères (French-Australian Scientific Co-operation Fund to Dr Jean Chazeau, Centre ORSTOM Noumèa). Glenn Shea and Sarah Smith assisted with fieldwork.

References

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. and A.M. Bauer. 1999. The scincid lizard genus Sigaloseps (Reptilia : Scincidae) from New Caledonia in the southwest Pacific: description of a new species and review of the biology, distribution, and morphology of Sigaloseps deplanchei (Bavay). Records of the Australian Museum (in press).
Sadlier, R.A. and A.M. Bauer. 2000. The scincid lizard genus Marmorosphax (Reptilia: Scincidae) from New Caledonia in the southwest Pacific: description of a new species restricted to high altitude forest in the Province Sud. Pacific Science - in press.
International Union for the Conservation of Nature and Natural Resources, 1996. IUCN Red List of Threatened Animals. IUCN, Gland , Switzerland.