Thursday, February 9, 2017

Sir David's Snail Is Not A New Species

Yes and no!
This is only slightly related to politics - in the sense that it is a good example of how media coverage often misreports and sensationalises environmental stories - but I thought I should just correct the record on the prominent announcement of a "new" Tasmanian snail.  It isn't a new species and it wasn't discovered in December 2016 as many sources are claiming.  What has happened is that an existing species has been moved into a new genus.

Sometime in the late 19th century, pioneering Tasmanian land snail expert William Frederick Petterd collected some snail specimens near Eaglehawk Neck.  Doubtless noting that some of them were much larger than a species considered  widespread through the state, Petterd left an enigmatic (and for me at least illegible) note with the specimens, but did nothing further with them.  Live specimens of the snail were first collected in the early 1970s resulting in the description of the new species Helicarion rubicundus by Dartnall and Kershaw in 1978.  At the time this was treated as a fresh discovery of a new species, Petterd's earlier specimens having not been noticed.



Initially it was thought that the species was restricted to an extremely small area near Eaglehawk Neck, but further surveying, firstly by Rob Taylor in 1989 and then by Helen Otley in the late 1990s (plus various records by yours truly and others) showed that the snail was present over much of the Forestier Peninsula and a small part of the Tasman Peninsula.  Taylor gave the species the nickname "burgundy snail", which has stuck as a common name for the species (not to be confused with the edible burgundy snail of France.)

Although the species can occur in very large numbers and can live in quite young eucalypt regrowth after logging, its very small natural distribution (c. 80 sq km) has led to it being listed as a Rare species on Tasmania's state threatened species list.  It is not listed as threatened federally.  The bushfire that tore through the town of Dunalley in January 2013 also burnt substantial areas of this snail's habitat.  The impact of the fire on the species hasn't been determined yet, but there are plenty of areas where it lives that were not affected.

In the last few years, scientists working at the Australian Museum in Sydney have been reviewing the family that the burgundy snail belongs to.  They have noticed - as has been suspected for some time - that the burgundy snail is quite different from the other, much smaller, Helicarion species present in south-eastern Australia.  As a result they are transferring the species to a new genus called Attenborougharion, named after Sir David Attenborough.

I thoroughly approve of this decision.  Sir David Attenborough is a great populariser of the science of natural history and the wonders of the natural world and there is nobody else like him.  It may seem there is nothing difficult about what he does in narrating natural history programs for TV, but to see how good he is, try watching all the rest.

However, the snail is not a new species.  The ABC and Nine News have incorrectly declared it to be such.  The Australian has got the basic story right in a very accurate report, though even that one isn't 100.00% correct.  Far from being confined to "isolated pockets of rainforest", the species in fact prefers wet eucalypt forests (where it can often be found inside bark rolls) and is very scarce in true rainforest, which in turn makes up a small proportion of its range.

The Huffington Post report somehow manages to declare the species was discovered in December while also referring (but not linking correctly to) the species' IUCN page and declaring the species to be "endangered" (a classification revoked by IUCN in 1996 - IUCN now lists it as vulnerable.)  The Mercury print edition report (as distinct from the online one) and this very good SMH piece by Marcus Strom are the only fully accurate reports I've so far seen.  I've seen dozens, on the other hand, with errors.

The story of the recognition of this uniquely Tasmanian and very localised species as a genus all of its own and the choice of name for it should be a good enough story by itself.  Unfortunately it is often difficult for journalists to grasp the exact details and hence reports of this kind easily become confused and exaggerated.  As a specialist in various things I often find that the mass media are most obviously inaccurate when talking about something I know something about - no matter what it is. It is difficult to avoid the conclusion that most media reporting on specialised issues is probably wrong.

I'll be speaking about Tasmanian snails on ABC radio 936 tomorrow c. 2:30 pm for anyone who wants to tune in!



2 comments:

  1. Yes, in nomenclatural parlance, _Attenborougharion rubicundus_ is a new *combination* - new genus for a pre-existing species. Like you, as a biologist I notice these things. I also noticed that a few websites failed to put the name in italics.

    I haven't seen the actual description or etymology of _Attenborougharion_, but _Arion_ is a genus of 'slug', and -_arion_ is a common suffix for pulmonate gastropods in general (like _Helicarion_). What does 'arion' mean? I know there was an illustrious horse in Greek mythology named Arion (very swift, immortal, and endowed with the power of speech). Is this the origin of the name?

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  2. I'm not familiar with the source of the genus name _Arion_.

    I do know that _Helicarion_ was originally spelled _Helixarion_ (_Helix_ being a snail genus name, so presumably and aptly meaning snail-slug) and much later officially altered by ICZN. The original author had switched to spelling it _Helicarion_ a few months later and had since been followed by most other sources in this.

    It has been common practice, especially recently, to describe new Australian _Helicarion_-like genera with the suffix -arion as a contraction of _Helicarion_.

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