By: Dr Glenn Shea, Category: AMRI, Date: 13 Feb 2018
Sorting out some overlooked skink lizards using museum collections.
I have spent much of my research time over the past 25 years working on a group of skinks from New Guinea and the Solomon Islands, the genus Sphenomorphus and its relatives. Despite this, I’ve only visited New Guinea three times, and I’ve not yet been to the Solomon Islands. How can this be?
I work on existing collections. New Guinea has been a magnet for explorers and collectors for over two centuries, and extensive collections of lizards from the region have accumulated in museums throughout the world. No one museum holds a majority of material for this group of skinks, although some collections have a preponderance of material from certain areas.
To gain an understanding of the diversity of this group of skinks, I spend much of my research time visiting museums around the world, and have examined about 20,000 specimens in collections in Australia, America and Europe, as well as local collections in New Guinea.
It is clear that there are numerous new species among these collections. However, part of the task of describing new species is to associate the existing names with actual species, and this work involves examining the original specimens previously used to define those species, so called “type specimens”. There have been many species names created for species in this group by biologists over the past two centuries. However, for a lot of these the published descriptions are very limited, concentrating on a few features that were considered important at the time. As more species are recognised and named, it becomes necessary to check additional features, often fine details of the arrangement of scales on the head, body and feet. Hence, while visiting other museums, I spend some of my time checking the original type specimens.
During the second half of 2015, I spent a month in Europe working through collections in Brussels, Leiden, Basel, Frankfurt, Berlin and Stockholm. The first fruits of this work were just published. From the Naturalis Biodiversity Centre, the natural history museum in Leiden, I described a new species of Sphenomorphus, based on two specimens in that collection that had been collected in 1952 from the Doberai Peninsula of Indonesian New Guinea (formerly known as the Vogelkop, or Bird’s Head Peninsula). The species was named Sphenomorphus dekkerae, honouring Ms Els Dekker, who had first noticed these specimens in 1977 in her unpublished thesis on the skinks of New Guinea in the Leiden collection. The species may have a very restricted range – the type locality is a small village on the shores of the Ayamaru Lakes in the centre of the Peninsula. At the time of collection of the specimens, the lakes were in good condition, but more recent biologists who have visited the region have advised that the formerly extensive lakes have largely dried up. It is not known whether these changes have affected the surrounding forests where the skink was found. Like many of the New Guinea and Indonesian skinks, the biology of the species remains little-known.
The second paper from my 2015 work involved a species that was described in 1928 from Misool Island, off the western end of New Guinea by a German herpetologist, Theodor Vogt: Lygosoma misolense. The original description of this species was insufficiently detailed to be sure of whether the species was distinct from other named species. In a previous paper, I had voiced the suspicion that the species might be the same as another more widespread species in New Guinea, Sphenomorphus simus. During my visit to the Zoologisches Museum in Berlin, I was able to examine the two original specimens of this species, and was able to confirm that it was the same as Sphenomorphus simus, extending the known distribution of that species to Misool Island, but reducing the number of named species of Sphenomorphus in the region.
Finally, while visiting the Naturhistorisches Museum in Basel, I was able to examine the skinks from Sulawesi collected by the Swiss naturalists Paul and Fritz Sarasin and named by the Swiss herpetologist Friedrich Müller in 1895. Among these was a small nondescript skink appropriately named Lygosoma inconspicuum by Müller, from the Bone Mountains in northern Sulawesi. In the 1950s, when the genus Lygosoma was split up, the species was transferred to the genus Scincella, based on what could be gleaned from the earlier description. This created something of a biogeographic anomaly, as Scincella was only otherwise known from south-east Asia and North America – no other Scincella was known from the Indonesian/Philippine island chains or elsewhere in the Pacific. My examination of the type specimen revealed that it was not a Scincella at all, but belonged to the genus Lipinia, a genus with a distribution centred over the Pacific. The species remains known only from that original specimen. However, recognition that it is a Lipinia may provide some explanation for its apparent rarity. Many Lipinia species are poorly-known because they are arboreal, living high in trees, a habitat often not targeted by reptile biologists.
While the total biodiversity of the skinks of New Guinea and Indonesia has not changed as a result of these studies (the addition of one new species is balanced by the loss of another through synonymy), we are now better placed to consider the conservation of three species – attention needs to be better focussed on Sphenomorphus dekkerae near thedegraded limestone lakes of the Doberoi Peninsula, and on searching in the right habitat for Lipinia inconspicuum, and less on any concern about a skink from Misool that turns out to be a common widespread species of New Guinea.
Dr Glenn Shea,
University of Sydney & Research Associate, AMRI
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