SFD in the Europe: a red herring or incoming catastrophe?

The pathogen Ophidiomyces ophiodiicola resulting in snake fungal disease (SFD) has been identified in the Europe. Nature paper here

This is of course alarming as it appears at first glance that we could be witnessing the realization of another global fungal scourge emerging, such as that which is condemning so many amphibian populations worldwide and bat populations across North America.

There is genetic variance to suggest that the European O. ophiodiicola is a novel strain of the American version, additionally the European cultures were slower to grow and lesions on carcasses appeared less severe in European specimens.

European native or an American import? It would be of no surprise to find that the former possibility is true, albeit with a caveat; considering the vast numbers of snakes imported for the pet trade since the 1970’s to present day. Unfortunately my money is on the import hypothesis, perhaps with the resulting strain having adapted to a less aggressive form owing to the less fertile environment. It may be possible that O. ophiodiicola isn’t going reek havoc in Europe as it hasn’t the same survivorship opportunities here.   

In the meantime lets not be complacent by waiting for evidence to pile up. If you work with native wildlife and especially if you keep exotics, lets reduce risk by disinfecting clothing and footwear in between areas.

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Frog Night Vision (think Picasso after dark)

Ever tried to see in colour, in the dark?

You cant…

But Frogs can!

Uniquely frogs have shown an ability to see colours at extremely low light levels, even until they reach the limit of their night vision. This is thought to be an animal kingdom first and its function in frog ecology can only be speculated. Frogs may communicate at different times using colours, when breeding for example, and as many frog species are highly active under low light, perhaps this is why an enhanced colour night vision is essential. Tropical forest dwelling species in particular have diversified under the low light conditions beneath the canopy layers. This suggests that perhaps the unique vision is in fact a significant protagonist to the evolutionary success of all frogs.

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Unknown Anuran, ID suggestions welcome. Photo credit: Anthony KeiC Wong, CC Gen. 2.0

It has long been understood that the rod cells of the frog retina has two types of sensitivity. In all other animals with rod cells, they simply react only to light intensities and so result in the typical night vision we experience, gradient and shape. It may be that rod cells in frogs can in addition, detect colour, gradient and shape. This novelty could be of some significance to medical researchers who want to investigate solutions and develop treatment for people suffered with failing vision.
Sources:

Science Daily

Primary research (open access) 🙂

Live Cropan’s Tree Boa!

This is really exciting stuff, for snake geeks but also for anyone who has dreamt of Amazonian adventures, in search of discovery, or rediscovery. The last recorded live specimen was collected from Brazils Atlantic forests and killed to represent the species holotype, in 1953. This physical reference had large scales, a large head but the typical tree boa body plan. Since then, a handful of only dead specimens have been recorded by researchers as most collectors appear to kill them out of fear. It also appears to be highly elusive within this unique biosphere. Like all boas the Cropan’s Tree Boa Corallus cropanii is harmless and so, researchers recently convinced locals to the Atlantic rainforests not to be so hasty. Their campaign has yielded an outstandingly beautiful adult female. What a privilege!

More here including images and video.

New Indian Gecko Species (Cyrtodactylus varadgirii) identified by Mitochondrial DNA and discrete morphological divergences

Cyrtodactylus varadgirii took some time to give itself away. It had long been considered to be a variant of another closely related species, C. speciosus. On closer visual inspection it was noted the believed variant had morphological differences’.

A multivariate analysis of 16 morphological measurements from C. speciosus, the ‘variant’ (C. varadgirii) and a confirmed -control- species C. collegalensis identified a distinct difference between C. varadgirii and C. speciosus. As expected the control was also distinct.

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The Holotype Cyrtodactylus varadgirii from Zootaxa, Agarwel et al. 2016 (open source).

Notable scale shapes and assemblages, long limb length, narrow body, and the colour of dorsal spots all set C. varadgirii apart.

Mitochondrial DNA (mDNA) analysis confirmed enough distinction of genetic material  for C. varadgirii to be described as a new species. mDNA is a good genetic record for recent changes in species relatedness as it is more prone to mutations over time.

Discrete, hard to define species like this are becoming easier to detect through the above combination of molecular and morphological evidence. Such studies could offer interesting subjects for microevolutionary studies and our understanding of biodiversity in general. They also highlight the need to try and define these species sooner rather than later, to inform appropriate conservation policy.

Source paper: A new species of the Cyrtodactylus (Geckoella) collegalensis (Beddome, 1870) complex (Squamata: Gekkonidae) from Western India

The Burrowing Hypothesis for Snake Origins

Before snakes evolved it is reasonable to imagine a snake-like lizard (think skink) exploring and wiggling across a water body or into the ground, to escape predation or in search of food. It has long been debated by scientists whether it was an aquatic or subtaranian habitat shift that eventually lead to complete legglessness.

Researchers (Yi et al. 2015) at the Universtiy of Edingburgh and the American Museum of Natural History have been analysing a fossil of Dinilysia patagonica. This is a long extinct snake or snake-like species that appears to share some important inner ear morphology with todays burrowing Squamates. The spherical vestibule is pronounced, within it the socullar otolith sits, which works by enhancing vibrations and thus increasing sensitivity seismic waves opposed to air born sound waves. Modern snakes have indeed lost the ability to pick up any air born sounds (arguably, will post).

Not all Squamates are burrowers but this correlation between the specific inner ear morphology of D. patagonica and those of todays burrowing Squamates, does suggest a deep evolutionary link. So the subtaranian theory holds a little more water.

Yi et al. 2015 is open access here

Snake Fungal Disease Pathogen Confirmed

The emerging “snake fungal disease” (SFD) which has been recorded among populations of Eastern and Midwestern US snake species, has been confirmed as Opidiomyces ophiodiicola. Lorch et. al. 2015 inoculated captive bred corn snakes Pantherophis guttalus with O. ophiodiicola and compared the symptoms they developed with those seen in wild populations, exhibiting SFD. A healthy captive bred control group of P. guttalus provided context for the comparisons. This may not seem like a great “breakthrough” in the typical sense but it will definitely streamline efforts to understand this serious threat and it should be regarded as a big step in the right direction.

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The Eastern Racer Coluber constrictor is on of several species now known to be affected by the Opidiomyces ophiodiicola fungal pathogen. Photo Credit: Alan Wolf, Creative Commons, Gen. 2.0

Researchers have been on the tail of the the SFD pathogen for about a decade. It is now a question of finding out how O. ophiodiicola acts within populations, under different environmental conditions and where it came from; and how it may act in the future. If we compare this pathogen to the infamous Batrachochytrium dendrobatidus (Bd) it’s clear that climate and human influenced dispersal should be considered.

Thankfully for our froggy friends, the amphibians can tentatively breath a sigh of relief thanks to Bosch et. al 2015. For the first time Bd has been eradicated from a wild amphibian population (Mallorcan midwife toads Alytes muletensis) by environmental disinfection. This is a great achievement but whether it can be scaled up to treat other threatened populations, remains to be seen.

Let’s hope that with continued research into SFD and specifically O. ophiodiicola any chances of a similar pandemic like that caused by Bd across world wide amphibian populations can be reduced.

Lorch et al. 2015 is open access here

National Wildlife Health Survey of the US Geological Survey have published in-depth description SFD events with some diagnostic photographs here

Bosch et. al. 2015 abstract is viewable here and a ZSL write up can be viewed here

More photography by Alan Wolf here