More snakes, because - thanks to Dave Hone - I have some more pictures to use (and, I'll be honest, at least some of my posts are 'picture-driven'). We've looked previously at the unusual, mostly small, worm-like, burrowing snakes grouped together as the scolecophidians here. In that article, however, I didn't really emphasise the small size of some scolecophidian species. This photo - taken by Dave in Mexico (is that Dino Frey holding the animal?) - makes the point well.
The smallest scolecophidians are Caribbean leptotyphlopids (aka threadsnakes, wormsnakes or slender blindsnakes) belonging to the genus Leptotyphlops. L. bilineatus (often also called L. bilineata) from Martinique* is said to have a MAXIMUM adult length of 108 mm and was, until recently, listed as the world's smallest snake (Carwardine 1995). Since then, Hedges (2008) has described the closely related species L. carlae from Barbados [shown below, on some sort of coin], and its total length is given as 104 mm (incidentally, though the holotype of this species was discovered in 2006, two specimens belonging to it have been known since, respectively, 1889 and 1963, it's just that they were misidentified as belonging to L. bilineatus).
* Specimens from Barbados and St. Lucia once referred to this species actually represent the close relatives L. carlae and L. breuili.
Hedges (2008) noted, however, that sample sizes have an obvious impact on views about maximum size. Of six Leptotyphlops species that have maximum lengths of less than 105 mm (L. dissimilis, L. nicefori, L. pungwensis, L. yemenicus, L. carlae and L. tanae) four are known from single specimens, and at least one of these is a juvenile. In the case of the Socotra Island species L. wilsoni, the two specimens known up until 2004 had total lengths of 100 and 101 mm respectively (meaning, incidentally, that this is the species that should have been in the Guinness Book of Records as 'world's smallest snake', not that Caribbean upstart L. bilineatus). But six additional specimens reported by Rösler & Wranik (2004) increased the maximum length to a gigantic 129 mm. Anyway, the point remains that some threadsnakes are very, very small, and in fact they're very probably at the extreme lower end of what's possible in terms of snake body-size. As for the other extreme: well, that's been in the news lately, as you'll know.
Regarding the identification of the Mexican species shown in Dave's photo, I'll have to pass on that I'm afraid. It might be a leptotyphlopid, but it might also be a typhlopid (or blindsnake).
Refs - -
Carwardine, M. 1995. The Guinness Book of Animal Records. Guinness Publishing, Enfield, Middlesex.
Hedges, S. B. 2008. At the lower size limit in snakes: two new species of threadsnakes (Squamata: Leptotyphlopidae: Leptotyphlops) from the Lesser Antilles. Zootaxa 1841, 1-30.
Rösler, H. & Wranik, W. 2004. A key and annotated checklist to the reptiles of the Socotra Archipelago. Fauna of Saudi Arabia 20, 505-534.
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Fastinating stuff. I'd heard of these snakes and knew they were small, but dint realise they were THAT small. I'll have to go looking for these as well when I get round to finding some wild caecilians...
Pretty neat. Had friend who was trying to raise "threadsnakes" as a hobby. More hassle than it was worth was her conclusion.
Timely post Darren - I'm hunting for Caribbean blindsnakes and our associated Amphisbaeana species this weekend. Apparently the blindsnakes are fairly common and easy to find but I'm damned if I can find them!
The coin btw is a US quarter dollar - its a standard US herpers' scale object for small species. I used one myself for a small snake just last week:
http://tai-haku.blogspot.com/2009/02/more-baby-photos.html
I still remember when I was many many years ago (I think about 15 years or so, I was still at primary school if I remember correctly) I had the chance to get a view on the archives of the zoological museum of Munich. Besides many many many other amazing things in the collection there was something I can remember especially well. There was a showcase which showed several animals which were found in anthills. Among this animals, mainly other insects and other arthropods of course, there was an incredigly small and thin snake, the smallest one I have ever seen, surely not much over 10cm. I don´t know if it was a juvenile or only a subadult specimen, but it was amazing to see such a gracile reptile.
Huh! I was under the impression that they were smaller than that, to be honest; 10cm is notably longer than my fingers. Thinking about what the ribs would look like for a snake that small, though, puts it back into perspective as ridiculously tiny. Amazing!
The coin in the photo is a US quarter, which is pretty close in diameter to the British pound coin. According to Wikipedia, the quarter is 24.26 mm while the pound is 22.5 mm.
That photo I think was actually taken by Dino Frey and features my hand. Dino identified it as a Typhlops, but i don't know enough about them to know if he was right.
Well, that certainly explains why it has "UNITED STATES OF AMERICA QUARTER DOLLAR" written on it!
Hmm, here in Britain we sometimes employ a form of humour known as 'sarcasm' :)
Then you should recognize it when we Americans use it. :)
Ah, I see, I missed your parenthetical comment. Now I feel like a two-bit goodfernothin'.
Very weird very little snakes... cheers Darren as usual for bringing new info to my ken... how ever did they first get noticed?
I was about to ask, what do they actually do... maybe Sordes answered that already? Hang out in anthills it seems... eating ants? or doing any other stuff besides? I guess it mite be kinda hard to observe tho... ;-)
So, at what age do scolecophidians begin to draw an allowance, and does the amount vary by size or taxon?
For Britishers unfamiliar with American coinage: the "quarter" (25 cent coin) shown is almost exactly the same size as a 5p (old shilling) coin. For Australians, almost exactly the same size as an Australian 10 cent coin. Which makes perfect sense if you assume pre- WW I rates of exchange.
So, what's that in millimeters? American, British, and Australian coins are equally foreign ot me I'm afraid.
Touché!
Naturalists' guide to United States coinage diameters:
Quarter (25 cents): 24 mm
Nickle (5 cents): 21 mm
Penny (1 cent): 19 mm
Dime (10 cents): 18 mm
Sizes rounded to nearest mm (sorry - couldn't find my calipers)
Naturally, I had to Google coin dimensions.
US Coin specifications
Euro coin specifications
Oops. I've developed a bit of a tin-ear for sarcasm since moving out to the caribbean; it doesn't get used so much down here. Oh well, at least we now all know more than we did about coinage. I didn't see any blind snakes or amphisbaeana) this weekend either (they were the only native reptiles I missed) so my whole comment was a bit of a shambles really.
Here are also some nice photos of baby grass-snakes I found: http://bestiarium.kryptozoologie.net/artikel/ringelnattern/
Grass-snakes are as adults of course not small, but this juveniles I found (I think it was two years ago) were really incredigly tiny, one of them formed a ball and was really not much bigger than the nail of my thumbnail.
Good to know! I'm from Texas, and we used to find one in the house every other summer or so. They're beautiful little things. I remember them looking just like the Barbados one in the photo, but slightly pinker.
Just curious; is there a commensurately small brain in that tiny little snakes incredibly small skull? Just how small can a terrestrial vertebrate animal's brain be and still direct its owner out in the comlpex world well enough to radiate as a range of species? Is there some coefficient of cellular structure modulus to organ size needed to function?