Friday, March 18, 2016

A giant viper from the Greek Pliocene


The type vertebra of Laophis crotaloides modified from
the original publication by Owen (1857). Image not to scale.
In 1857, British palaeontologist Richard Owen described Laophis crotaloides, a new species of viperid snake, on the basis of 13 large, fossilized vertebrae from Megalo Emvolon, near Thessaloniki, in northern Greece. According to Owen, the vertebrae belonged to a very large viperid with striking similarity to modern rattlesnakes of the genus Crotalus. Ever since, Laophis has been an enigma. Almost all subsequent authors neglected it or considering it problematic, possibly because it was estimated to reach three meters in length.

In a new paper Georgalis et al. (2016) report on a previously undescribed vertebra of a large snake from the area of the type locality of L. crotaloides in northern Greece. Although the vertebra is fragmentary, it shares with Laophis crotaloides an overall large size and clear viper features. The authors assigned the vertebrae to Laophis crotaloides. Unfortunately, the broken fossil precludes any precise conclusions about the taxonomic status of this fossil snake and the affinities of Laophis to the other members of the Viperidae. Nevertheless, this new material confirms the validity of the taxon and suggests certain vertebral characters featured in the original description by Owen (1857) were inaccurate. The maximum length of the condyle of the most recent specimen is 16.3 mm, the longest condyle reported for any European viperid. The vertebrae is from the Pliocene.

The mammal fauna of Megalo Emvolon is speciose and relatively well studied. It includes bovids, a suid, an equid, various rodents and lagomorphs, a canid, and a cercopithecid primate. A single species of bird is known from the site, a peafowl. Reptiles are represented by Laophis crotaloides (the only squamate) and numerous small and giant tortoises. The mammal fauna indicates the paleoenvironment of Laophis crotaloides was semi-arid.

Citation
Georgalis, G. L., Szyndlar, Z., Kear, B. P., & Delfino, M. (2016). New material of Laophis crotaloides, an enigmatic giant snake from Greece, with an overview of the largest fossil European vipers. Swiss Journal of Geosciences, 1-14.

A new colubrid genus and species from India

Wallaceophis gujarateneis sp. n 

A photograph of an uncollected snakes in 2007 paper depicted a small yellow snake with two dark stripes, the species discussed in the article lacked stripes, and a follow up investigation revealed a new species in a new genus with a very ancient history. Mirza et al. 2016 obtained a second specimen of the snake from Gujarta, India. Results from molecular data show that the snake belongs to a clade arid dwelling snakes with Platyceps, Eirenis, Spalerosophis, Macroprotodon and Lytorhynchus. The snake however greatly differs morphologically as well as genetically which warrants erection of a new genus to accommodate the new species from Gujarat.

Wallaceophis gujarateneis sp. nov. measures SVL 250–930 mm and differs from most colubrid genera in lacking hypapophyses on posterior dorsal vertebrae  and in bearing nine maxillary teeth and the posterior-most teeth are subequal, nine palatine teeth. Dorsal scale reduction characterized by vertebral reductions, increase of scale rows posterior to neck, a single lateral reduction at midbody and regular vertebral reductions in posterior half of the body. Rostral not visible from above, a small presubocular present. Eight supralabials, fourth and fifth in contact with orbit, anal undivided, 215–216 ventrals, 51–54 subcaudals, hemipenis subcylindrical, spinose throughout and 3–4 dorsal scale row wide black longitudinal stripe running from the post nasal to the tail tip on each side on a wheat colored dorsum.

The type specimen was collected from a manmade water hole near an irrigation canal along with a few juveniles of Xenochropis piscator. The species appears to be diurnal as it was collected at ca. 11:15 hours. The type locality, Khengariya village, is situated in the dry plains of central-western region of Gujarat state. The type locality habitat is in an area of Desert thorn forest. The annual precipitation is 838mm. Majority of the precipitation occurs during the months of July and August. The temperature varies from as low as 12°C during winter and as high as 43°C during the hot summer days. The snake snakes behavior suggests it is aquatic and fossorial. An individual retained in captivity was readily ate a Hemidactylus gecko.

Citation:
Mirza ZA, Vyas R, Patel H, Maheta J, Sanap RV (2016) A New Miocene-Divergent Lineage of Old World Racer Snake from India. PLoS ONE 11(3): e0148380. doi:10.1371/journal.pone.0148380

Irish Snakes?

If snakes were introduced to Ireland, surely they would hav to 
look like this.

The legend of St. Patrick banishing snakes from the emerald isle some 1,500 years ago is indelibly etched in folklore -- even if science suggests snakes were unlikely to have colonized the country following the last ice age.

But what would happen if St. Patrick's scaly foes were introduced now? Would Ireland's native wildlife sink or swim?

Experts from Trinity College Dublin believe snakes could certainly slither into Ireland's ecosystems if introduced but would likely cause trouble for native ecosystems. There are enough troublesome pests in Ireland today, such as the introduced New Zealand flatworm, which people would like to send on its merry way with some modern-day St. Patrick-style sorcery.

Associate researcher in Trinity's School of Natural Sciences, Collie Ennis, is a snake expert. He said: "If you look across the water, the UK has very similar environmental conditions to ours and snakes fit right in. Native animals that would not have evolved around snakes as predators would be lost if snakes were introduced here but snakes could probably persist."

Interestingly, a number of attempts have been made to introduce grass snakes, one of three species that are native to Britain, over the past 100 years. Until recently, grass snakes could even be bought in pet shops throughout the land.

Collie Ennis added: "There are anecdotal records of individuals releasing several grass snakes along the Royal Canal in Dublin but luckily the snakes failed to establish populations. This could simply be due to the small numbers of snakes introduced, the unappealing climate, or to a combination of these factors."

Worryingly, Professor of Zoology at Trinity, Yvonne Buckley, says there are lots of other invasive species that have established, and whose ecological influence is growing quickly. Some of these species present a real threat to Ireland's environment and economy.

Near the top of that list is the New Zealand flatworm, a relative newcomer to Ireland's shores, which feeds on native earthworms that provide important ecosystem services as well as currying favor with farmers for enhancing the fertility and drainage of agricultural soils.

Professor Buckley said: "New Zealand flatworms are not snakes but they are long and legless, and our ecosystems and farms would benefit from their removal. It certainly would be legendary if I could magically banish these legless interlopers! Unfortunately it costs a lot more to banish unwanted pests now than it did in St Patrick's day, so introduction of snakes would be a very expensive mistake."

Other invasive species that threaten Irish biodiversity and harm the economy include zebra mussels, muntjac deer, harlequin ladybirds, mink, mitten crabs, rhododendron and Japanese knotweed.

Trinity College Dublin.