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Tale of the Takydromus

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Two fighting male individuals of Japanese grass lizard (Takydromus tachydromoides). UPDATE: err, or is that a male and female engaged in courtship? Photo by Materialscientist, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

I said a while back that I intended to make some overdue headway into the diversity of lacertid lizards: Lacertidae being the clade that includes many of the more familiar, conventionally ‘lizard-shaped’ lizards of Europe, Asia and Africa. Beleaguered by commitments and absolutely unable to produce anything lengthy for Tet Zoo (and unwilling to repost an old article from the archives), I thought I’d produce a shortish article on a lacertid I haven’t written about before: Takydromus… though, seeing as this taxon contains something like 21 species, I’m actually talking about a whole group of lacertids, not a stand-alone singleton. [Image above by Materialscientist.]

Actually… about that number of species. There are a few cases where people have reported northern, temperate-climate Takydromus taxa from tropical places (example: specimens referred to the Russian-Korean-Chinese species T. wolteri have been ‘identified’ in Vietnam), leading some to suggest that the tropical identifications are erroneous, hinting at the existence of additional, cryptic species (Lin et al. 2002). Indeed, two such species – previously included within T. formosanus – were named from Taiwan in 2008 (Lue & Lin 2008). At the time of writing the newest species is T. hani, named this year from Vietnam.

Less than ideal photo of captive T. sexlineatus... but check out that tail! Image by Bando26, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

In general appearance, these lizards – typically called grass lizards or oriental racers – are greenish or brownish, have a distinctly depressed head and a really long tail. That tail can be as much as five times as long as the combined length of the head, neck and body. This means that the centre of gravity is placed well back, a fact which allows for some mean acrobatic feats (read on). The keels on the large, plate-like dorsal scales form continuous longitudinal rows in many species. Many details of the scalation in Takydromus are unusual and unique within lacertids (Arnold et al. 2007).

Another Japanese grass lizard (T. tachydromoides) (this species was also reported in 1958 from South Korea); photo by KENPEI, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

If you know squamates, you’ll know that hemipenis structure is important in working out how species might be related to another. Surprise surprise, Takydromus has weird hemipenes: the lobes at the tips are unusually thick-walled and – so far as we know – the hemipenes don’t change shape much across the seasons. Oh yeah, did I say that squamate hemipenes normally change in size and shape according to season? As you might predict, they are biggest and most elaborately ornamented during the breeding season.

Sikkim grass lizard (T. sikkimensis) specimen figured by Bhupathy et al. (2009). This specimen (discovered in 2006) verified the existence of a species first named in 1888 but mostly regarded in recent decades as synonymous with T. sexlineatus. In this species, the tail is 'only' 306% SVL.

Takydromus species occur across eastern Asia, from Japan in the north down to Sumatra and Java in the south. About half of all species inhabit islands along the Pacific margin of Asia, including Taiwan, Japan and the Ryukyu Islands. This distribution means that there are species of humid tropical climates, cool temperate ones and everything in between. The high island-endemicity of the group also makes them potentially vulnerable to the sorts of anthropogenic problems associated with being restricted to islands (to my knowledge, little is known of the conservation status of these lizards, nor of how vulnerable they might be to extinction risk).

Some Takydromus species are forest-dwelling lizards while others occur in open habitats and show a preference for climbing among tall grasses. In fact, some are mostly ground-dwellers (e.g., T. amurensis and T. sylvaticus) while others are highly agile, acrobatic climbers that wind their tails around branches or grass blades when climbing. The more proficient of the climbers (like T. sexlineatus and T. dorsalis) are able to project the body stiffly outward from the object they’re climbing, the forelimbs laid back against the flanks (Arnold 1997). Bipedal standing, again with the forelimbs flat against the body, is practised in the longer-tailed species (like T. sexlineatus) when they’re trying to catch airborne or elevated prey. Arnold (1997) described this pose as ‘penguin-like’. He also suggested that the large, continuously overlapping dorsal and ventral scales might help provide stiffness for the body when the animals stand in this pose.

Female T. sexlineatus; image by Acapella, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

One of the most interesting things about these lizards is that they have tricuspid teeth at the back of the jaws (a feature that, elsewhere within Lacertidae, is also present in Gallotia and the Miocene taxon Miolacerta… wow, imaginative name on that one). All Takydromus species are arthropod predators and all (so far as we know) are oviparous.

>Massively< simplified lacertid phylogeny, showing early divergence into Gallotiinae and Lacertinae, and with Takydromus being the sister-taxon to the rest of Lacertinae. Acanthodactylus by Richard Hing, Takydromus by Acapella, Gallotia by Petermann, Psammodromus by Wolfgang Wüster.

As for where Takydromus fits within Lacertidae, a general similarity with Zootoca vivipara – the Palaearctic Viviparous lizard – has led to the idea that they’re somewhere within the lacertid clade Lacertinae, and close to Zootoca (Arnold 1989). Exactly this relationship was recovered by Arnold et al. (2007) in their morphology-based analysis, though things were rather less tidy in the molecular ones: they preferred topologies where Takydromus is the sister-taxon of all other lacertines excepting the members of Eremiadini (ah yes, them. Another time, ok?). Fu (1998, 2000) found Takydromus to be the sister-taxon to all other lacertines.

There’s no definite fossil record for Takydromus but Miolacerta might be a close relative or stem-member of the lineage (Arnold et al. 2007). It’s inferred that Takydromus descends from an ancestor that moved east from the more westerly area where lacertids mostly evolved, and then diversified extensively in eastern Asia and along the Pacific margin.

Arnold (1997) provided a wealth of data on the anatomy of the Takydromus species and produced a morphology-based phylogenetic hypothesis for the clade. As is typical for species that contain numerous species, there have been suggestions from time to time that certain of said species should get their own genera, so both Platyplacopus Boulenger, 1917 and Apeltonotus Boulenger, 1917 are today regarded as synonyms of Takydromus. Arnold (1997) found Takydromus to group into two main clades and he hence suggested that the name Platyplacopus could be applied to the clade that includes its type species (T. keunei from southern China, Hainan and Taiwan). However, molecular phylogenies have not supported this tidy division and Platyplacopus now seems to be polyphyletic (Lin et al. 2002, Ota et al. 2002). [Image below by TANAKA Juuyoh.]

Another view of another Japanese grass lizard (T. tachydromoides). Image by TANAKA Juuyoh, licensed under Creative Commons Attribution 2.0 Generic license.

So, for now, I can rest, secure in the knowledge that I’ve written about another group of lacertids at Tet Zoo. Only another 15-20 major lineages to go.

For previous Tet Zoo articles on lacertids, see…

Refs – -

Arnold, E. N. 1989. Towards a phylogeny and biogeography of the Lacertidae: relationships within an Old-World family of lizards derived from morphology. Bulletin of British Museum of Natural History (Zoology) 55, 209-257.

-. 1997. Interrelationships and evolution of the east Asian grass lizards, Takydromus (Squamata: Lacertidae). Zoological Journal of the Linnean Society 119, 267-296.

- ., Arribas, O. & Carranza, S. 2007. Systematics of the Palaearctic and Oriental lizard tribe Lacertini (Squamata: Lacertidae: Lacertinae), with descriptions of eight new genera. Zootaxa 1430, 1-86.

Bhupathy, S., Chettri, B. & Bauer, A. M. 2009. Rediscovery and revalidation of Takydromus sikkimensis (Günther, 1888) (Squamata: Lacertidae) from Sikkim, India. Journal of Herpetology 43, 267-274.

Fu, J. 1998. Toward the phylogeny of the family Lacertidae: implications from mitochondrial DNA 12S and 16S gene sequences (Reptilia: Squamata). Molecular Phylogenetics and Evolution 9, 118-130.

- . 2000. Toward the phylogeny of the family Lacertidae – why 4708 base pairs of mtDNA sequences cannot draw the picture. Biological Journal of Linnean Society 71, 203-217.

Lin, S.-M., Chen, C. A. & Lue, K.-Y. 2002. Molecular phylogeny and biogeography of the grass lizards genus Takydromus (Reptilia: Lacertidae) of East Asia. Molecular Phylogenetics and Evolution 22, 276-288.

Lue, K.-Y. & Lin, S.-M. 2008. Two new cryptic species of Takydromus (Squamata: Lacertidae) from Taiwan. Herpetologica 64, 379-395.

Ota, H., Honda, M., Chen, S.L., Hikida, T., Panha, S., Oh, H.-S. & Matsui, M. 2002. Phylogenetic relationships, taxonomy, character evolution and biogeography of the lacertid lizards of the genus Takydromus (Reptilia: Squamata): a molecular perspective. Biological Journal of the Linnean Society 76, 493-509.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Heteromeles 9:57 am 09/15/2013

    Neat! How mobile and/or prehensile are those tails?

    Link to this
  2. 2. Hai~Ren 10:46 am 09/15/2013

    Despite its wide distribution across Sundaland (where it is the only lacertid), Takydromus sexlineatus is absent from Singapore, which makes me wonder if it’s due to habitat preference; this species appears to prefer grasslands and open woodland, habitats that did not exist here until at least the last couple of centuries. Of course, now that much of the original tropical rainforest has been cleared and many green spaces consist of parkland, secondary scrub and grassland, I wonder if it’s possible that this species might somehow arrive as a stowaway in cargo from Malaysia, Indonesia, or Thailand and colonise these areas, much like how the changeable lizard Calotes versicolor has become established in recent decades.

    Link to this
  3. 3. naishd 12:17 pm 09/15/2013

    Thanks for comments. Heteromeles (comment # 1): the tail is reasonably prehensile; as described above (I think), the animals are certainly able to loosely coil it around objects when climbing. It’s certainly not as prehensile as, say, a chameleon tail though. So far as I know, this is unique within Lacertidae. Interested to know if we would guess this degree of prehensility from the osteology…

    Darren

    Link to this
  4. 4. naishd 12:19 pm 09/15/2013

    Oh, and I really must remember to post a picture of those tricuspid teeth some time. More people need to know that lizards are not all homodont. The lateral cusps are very prominent in some Takydromus species but subtle in others. Their prominence also varies across ontogeny.

    Darren

    Link to this
  5. 5. paradalis 3:32 pm 09/15/2013

    There were tons of them on the marine base camp shwab Okinawa when I was there in the early 90′s..in some areas you can find 30-50 or more of them in square meter of grass

    Link to this
  6. 6. paradalis 3:55 pm 09/15/2013

    Japan now I cant help but wonder how many species we will loose from fukashima radiation..I hope zoologists are trying to get specimens and breeding stock before the gene pools get mutated.

    Link to this
  7. 7. Heteromeles 7:27 pm 09/15/2013

    @Paradalis: probably we won’t lose any species to Fukushima. After all, we didn’t lose any to Chernobyl, and that was worse by any measure. Damaged, yes. Lost? Not so much.

    Link to this
  8. 8. David Marjanović 7:17 am 09/16/2013

    That tail can be as much as five times as long as the combined length of the head, neck and body.

    Wow. That surpasses Pontosaurus, the pleurosaurs, the urocordylids, the aïstopods, and even the diplodocids! Are these the longest tails ever?

    Link to this
  9. 9. naishd 7:26 am 09/16/2013

    Longest tails ever? Have you ever seen the Greater long-tailed shrew-tenrec Microgale principula?

    Darre

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  10. 10. Dartian 7:51 am 09/16/2013

    Darre(n):
    Have you ever seen the Greater long-tailed shrew-tenrec Microgale principula?”

    I must confess that I haven’t. How long is its tail?

    Link to this
  11. 11. naishd 3:22 pm 09/16/2013

    I checked Garbutt’s Mammmals of Madagascar: as is so often the case, my memory lead me astray somewhat. For the Lesser long-tailed shrew-tenrec* Microgale longicaudata, Gabutt gives the head + body length as 60-75 mm and the tail length as 110-160 mm. So, tail = 183-213% of head + body length. For the Greater long-tailed shrew tenrec, head + body is 65-80 mm and tail is 135-170 mm, meaning that the tail is 208-212.5% of head + body length. I had gotten the impression (from the photo Garbutt shows on p. 84) that the tail was something crazy like 5 times head + body length. Nope.

    * Garbutt (and many other authors) calls these animals ‘shrew tenrecs’, but – following conventions used elsewhere in zoological nomenclature – I really think they should be shrew-tenrecs (some ornithologists would want them to be shrewtenrecs, but that looks silly).

    Ref – -

    Garbutt, N. 1999. Mammmals of Madagascar. Pica Press, Mountfield.

    Darren

    Link to this
  12. 12. Dartian 1:03 am 09/17/2013

    Darren:
    I had gotten the impression (from the photo Garbutt shows on p. 84) that the tail was something crazy like 5 times head + body length. Nope.

    OK, thanks for the clarification. Bye bye, super-long-tailed tenrec. :(

    Mammals generally don’t seem to go for really long tails (an appendage such as a tail is, obviously, a major source of heat loss in an endothermic animal). So which mammal does have the longest tail relative to head+body length then? I’m guessing it might be one of the pangolin species, but I don’t know for sure.

    Link to this
  13. 13. naishd 3:56 am 09/17/2013

    A few years ago I compiled a list of long-tailed mammals (this was for the kid’s book Dinosaur Record Breakers, since one section deals with ‘longest tail’), let me see if I can find it…

    I think the shrew-tenrecs won.

    Darren

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  14. 14. llewelly 5:33 am 09/17/2013

    Nice photo of a lesser long-tailed shrew tenrec , whose tail is nearly as long (proportionately) :

    http://books.google.com/books?id=ftjKjbPKF2oC&pg=PA47

    (2007 edition of Garbutt’s book. Sadly pg 48 is not available in the preview. Watch out for all the lemur and bat pictures in this book. They could take up a fair chunk of your day.)

    Link to this
  15. 15. naishd 5:37 am 09/17/2013

    Ok, I can’t find that list. It included the two long-tailed shrew-tenrecs, the Long-tailed pangolin Manis tridactyla and Snow leopard Panthera uncia, possibly Fossa Cryptoprocta ferox as well. Madagascar for the win on long-tailed mammals, then.

    Darren

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  16. 16. Dartian 5:46 am 09/17/2013

    Darren:
    It included the two long-tailed shrew-tenrecs, the Long-tailed pangolin Manis tridactyla and Snow leopard Panthera uncia, possibly Fossa Cryptoprocta ferox as well.

    No rodents (e.g., jerboas) or primates (e.g., langurs) in the top ten?

    Link to this
  17. 17. David Marjanović 9:55 am 09/17/2013

    http://books.google.com/books?id=ftjKjbPKF2oC&pg=PA47

    There is no preview of that book.

    Link to this
  18. 18. naishd 10:38 am 09/17/2013

    Dartian: I’m pretty sure it was a top 5, and (so far as I recall) no rodents or langurs included. David M. Watson reminds me on twitter that the Long-tailed dunnart Sminthopsis longicaudata should be on the list (tail something like 218% of head + body length). So should the Little long-tailed dunnart S. dolichura (tail something like 160% of head + body length).

    Darren

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  19. 19. Dartian 11:17 am 09/17/2013

    Darren:
    David M. Watson reminds me on twitter that the Long-tailed dunnart Sminthopsis longicaudata should be on the list (tail something like 218% of head + body length). So should the Little long-tailed dunnart S. dolichura (tail something like 160% of head + body length).

    What about the Central American woolly opossum Caluromys derbianus? I’d be willing to bet that it has both the snow leopard and the fossa (at least) beat when it comes to relative tail length.

    Link to this
  20. 20. Dartian 12:24 pm 09/17/2013

    I did a little digging on snow leopard tail lengths. Different sources say different things, as is to be expected. However, a reputable reference, Mel & Fiona Sunquist’s Wild Cats of the World (2002) states that snow leopard tails are ‘only’ as long as 75-90 % of the head+body length.

    In other words: Sorry, Darren, but the snow leopard doesn’t belong anywhere near the all-mammal top 5. And I’m starting to have more and more doubts about the fossa too.

    Link to this
  21. 21. naishd 12:29 pm 09/17/2013

    ‘Only’ 75-90%? Huh, ok. Well, I can’t find the list, so am not totally sure that Snow leopard was on the list anyway. Poor lacertids — having their comment thread hijacked by wretched mammals…

    Darren

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  22. 22. Heteromeles 5:48 pm 09/17/2013

    Aw, and here I was thinking that Takydromus has one of the goofiest ways to evolve towards snakiness that I’ve ever seen.

    Link to this
  23. 23. Halbred 7:41 pm 09/17/2013

    Speaking of prehensile tails, I can report through personal observation that leopard geckos–which have fat, not-particularly mobile tails–have enough muscle control in their tails, especially at the distal end, to get a surprisingly firm grip on things like fingers. The tail certainly can’t wrap around one’s finger, but it curls that way (again, only at the distal end) and does attempt to “get a grip,” as it were. It’s kind of adorable.

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  24. 24. BilBy 8:24 pm 09/17/2013

    Takydromus tails look like Pletholax gracilis – the legless pygopodid from W. Aus. Pletholax is ridged in the same way and feels like a stick or piece of wire in the hand. It also goes more or less rigid and can reach across interstices between low twiggy branches (allegedly). Is the odd ridging to do with semi-arboreal activity in both species? Pletholax has low incidence of autotomy while Takydromus (I think) drops its tail merrily – which must have an impact on climbing ability i would have thought.

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  25. 25. Dartian 2:19 am 09/18/2013

    BilBy:
    which must have an impact on climbing ability i would have thought

    That’s what one would intuitively think, yes, but it might in fact not be so. Research has shown that tail autotomy affects locomotor performance negatively in some lizards (i.e., slows down their running speed), but in other species partial tail loss may actually increase running speed. In yet other lizard species tail autotomy has no obvious effects on locomotor performance.

    Takydromus, or at least the species Takydromus septentrionalis, would seem to belong to the last category. Lin & Ji (2005) showed that tail loss didn’t start to significantly compromise locomotor performance of T. septentrionalis until the length of the removed tail was longer than 70% of the original tail length. (Admittedly, Lin & Ji’s study only looked at the effects of partial tail loss on running performance, not on climbing.)

    Reference:
    Lin, Z.-H. & Ji, X. 2005. Partial tail loss has no severe effects on energy stores and locomotor performance in a lacertid lizard, Takydromus septentrionalis. Journal of Comparative Physiology B 175, 567-573.

    Link to this
  26. 26. naishd 3:50 am 09/18/2013

    Thanks for comments. A similarity between Takydromus and certain of the pygopodids (like Pletholax) struck me too, as did a rough similarity between these lacertids and the reduced-limbed Chamaesaura cordylids. Both groups have been covered on Tet Zoo before. See…

    Evolutionary intermediates among the girdled lizards
    Blindsnake mimics, scaly-foots and javelin lizards (gekkotans part XI)

    Darren

    Link to this
  27. 27. David Marjanović 7:18 am 09/18/2013

    Aw, and here I was thinking that Takydromus has one of the goofiest ways to evolve towards snakiness that I’ve ever seen.

    Yeah, it has a very noodly appendage.

    Link to this
  28. 28. Dartian 7:47 am 09/18/2013

    David:
    Yeah, it has a very noodly appendage.

    I saw what you did there. ;)

    Link to this
  29. 29. Heteromeles 10:46 am 09/18/2013

    Hi Darren,

    Not that you need another headache, but when reading those cool articles you posted from Tetzoo 2.0, it appears that the within-article links to other Tetzoo 2 articles are all broken. Not sure why. Perhaps you need some volunteer to create a page of all the articles with the right links, so that they can be linked to from Tetzoo 3 (and no, I’m not volunteering). Got any students who desperately need extra credit?

    Link to this
  30. 30. llewelly 4:48 pm 09/18/2013

    “There is no preview of that book.”

    hm. Works for me. Maybe it is yet another book whose google books preview is only available in the US. : (

    My apologies.

    Link to this
  31. 31. naishd 5:07 pm 09/18/2013

    Heteromeles (comment # 29): yup, all the links on ver 2 are dead, but I can’t even begin to correct them since I can’t get behind the scenes at ScienceBlogs anymore (understandable). I pasted in the ver 2 links above from an older ver 3 article, but then discovered that they didn’t work… and thus had to go re-do all of them. Tedious.

    Darren

    Link to this
  32. 32. Heteromeles 6:55 pm 09/18/2013

    Hmm. Perhaps someone who regularly reads this has a student or students who desperately need a tedious task to make up necessary grade points or work study hours. Just a thought…

    Link to this
  33. 33. llewelly 4:36 am 09/19/2013

    old form:

    http://scienceblogs.com/tetrapodzoology/2008/04/cee_functional_anatomy_teaser.php

    new form:

    http://scienceblogs.com/tetrapodzoology/2008/04/24/cee-functional-anatomy-teaser/

    so the fix is:

    (a) Insert the day the article was published on (in blog’s timezone, not the author’s timezone?) between the month and the blog title.

    (b) Replace the “.php” at the end of the blog title with “/” .

    This is the sort of thing best done with a script.

    Link to this
  34. 34. David Marjanović 10:03 am 09/19/2013

    I saw what you did there.

    Arrrrrrrrrr.

    Link to this

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