Perrottetia dermapyrrhosa, one of the newly described species from Thailand. Credit: Somsak Panha. License CC BY 3.0
Each of the species is only found on one or a handful of hills, some of which have become limestone quarries. Pretty impressive, as a quarry is not a friendly habitat for an animal whose main predator is the boot.
As well as coming in a range of fancy colours, the new species are characterised by nothing less than the shape of their genitals. All from the Perrottetia aquilonaria has a club-shaped penis and penial hooks (sounds painful?), while P. dermapyrrhosa has a long penial sheath, long, scattered penial hooks and vaginal hooks.
It seems like snail penises are a common way to distinguish between species, and there must be quite an art to it. Take this rather lengthy description of P. aquilonaria’s junk.
“Genitalia with a long, slender penis; penial sheath short, about half of penis length; internal wall of introverted penis with black to brown penial hooks; vas deferens passes through a short section of penial sheath before connecting distally to penis; vagina and free oviduct short to long, vaginal hooks may be present; gametolytic duct and sac may not extend as far as albumin gland; seminal vesicle present with about the same length from vesicle to talon.”
If you click through to the complete article, published open-access on peer-reviewed ZooKeys, you can even see some pictures of penial hooks and vaginal corrugated folds. Come on, what else are you going to do with your day?
Perrottetia aquilonaria, another newly described species. Credit: Somsak Panha. CC BY 3.0
It all sounds rather saucy, and top-notch science research, but I got caught up on this idea of a carnivorous snail. I mean, what IS that? It sounds like something from an old Doctor Who episode, back when the creepy alien du jour was footage of maggots, zoomed in so they looked gigantic. These day’s it’s terrifying ghosts with their mouth all screamy and sideways and it looks like something from The Exorcism of Emily Rose.
They may not be lions and tigers, but carnivorous snails are nonetheless vicious. Some of the species we have in Australia are small and are probably in your garden right now, others are big black ones that live in the Victorian rainforest.
Carnivorous snails hunt other snails, following their slime trail until they catch up with them. Now, most snails have a tongue like a rasp, and they eat lettuce leaves and such by simply licking them away with their tongue-which-works-like-teeth. Carnivorous snails upsize the rasp for big-ass hooks, and when they catch up with their prey they give them a lick and stick their hooks in.
If you’ve ever poked a snail, you know they slip inside their shell and produce gross foam to stop you poking them (no means no). Unfortunately they try the same trick when they get licked by a carnivorous snail, and the attacker has already shoved its hooks in so the snail unwittingly sucks the hunter right into its shell with it. Then the predator just licks away until there’s nothing left.
Actually, that does sound like a creepy Doctor Who episode.
Carnivorous snails also hunt worms, hooking ’em and eating ’em like spaghetti. There’s a great discussion of carnivorous worms on land and sea here on the ABC Radio website.
The research was performed by Chulalongkorn University, Bangkok and the Natural History Museum, London.
Siriboon, T., Sutcharit, C., Naggs, F., & Panha, S. (2013). Three new species of the carnivorous snail genus Perrottetia Kobelt, 1905 from Thailand (Pulmonata, Streptaxidae) ZooKeys, 287, 41-57 DOI: 10.3897/zookeys.287.4572