By: Glenn Shea, Category: AMRI, Date: 04 Mar 2016
Serendipity, morphology and museum collections combine to determine a new species of blind snake from the southern Northern Territory.
Blind snakes are an acquired taste – skinny burrowing snakes that look like overgrown earthworms and feed on ants. They are nonetheless important components of the subterranean fauna, among the few vertebrates that live their life under the surface, and nearly 50 species are known from Australia, many only recently discovered. They are notoriously difficult to identify, because there are few characters that differentiate between many species, and those features that do exist are difficult to see. The scales on blind snakes are thin, shiny and nearly transparent. It is very hard to distinguish one scale from another except under a microscope, with lighting at just the right angle. This is especially true for the smaller species. Consequently, there are few people willing to study them, and much that awaits discovery about them.
During a research visit to the Museum and Art Gallery of the Northern Territory in the mid 1990s, to look at some reptile specimens for another project, I made time to spend a couple of hours looking through the jars of blind snakes in their collection to check the identifications and gather distribution data. Most of the taxonomic work on blind snakes begins in this way, with the examination of slowly accreting museum collections.
On looking through the jars, I found one that was labelled as Ramphotyphlops wiedii, an eastern Australian species. This roused my interest, because the specimen had been collected during a 1989 survey of a remote nature reserve in the southern Northern Territory, a long way from the known distribution of that species.
It certainly looked like wiedii, but was it? Over the next two decades, I waited to see if another individual was collected to confirm the record, but no luck. Blind snakes are difficult to collect, especially out in the deserts. In eastern Australia, they can occasionally be found in the soil under rocks and logs, but such ground cover is hard to find in central Australia, and there’s an awful lot of sand to dig on the off-chance of finding one. You are more likely to find blind snakes serendipitously by living in an area for a long while and waiting for one to cross your path on rare forays above the surface. This method wasn’t a possibility out where this specimen had come from.
The alternative was to see if the features of this specimen were within or outside the known extremes of variation in wiedii. However, because of the previous lack of work on blind snakes, no-one had ever looked at a lot of specimens of that species. The Australian Museum has gradually accumulated over the past century nearly 140 specimens of wiedii, many of them donated by members of the public, but often preserved in twisted positions that made examining their scales difficult. One of the very useful characters differentiating blind snake species is the number of scales along the body, but counting the 400 or so scales from head to tail on 140 shiny snakes about 20cm long and thin as a shoelace is a task only suited to serious masochists. All the body scales look alike, and it is very easy to lose count or drift off to sleep as the mental hundreds mount up on each specimen.
Eventually I was able to finish the task, and found that the central Australian specimen fell outside the range of variation in wiedii in the number of dorsal scales, the shape of the scale on the tip of the snout (the rostral scale) and the length of the nasal cleft (a split in the scale surrounding the nostril). It was only then that I was confident that a new species had been discovered.
The discovery of this new species (Anilios fosser) emphasises the importance of museum collections. Not only do they house many species awaiting discovery, but the process of identification and description of new species involves comparison with related species. It is museums that hold this comparative material, with collections slowly building over time to the point where it is possible to define the extent of variation within populations and species of organisms.
Dr Glenn Shea, University of Sydney & Research Associate, AMRI
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