The Race of Racers

Snakes are, for the most part, fairly retiring animals, little seen even in areas where they may be abundant. In much of North America, however, one of the most commonly encountered snake species is the racer Coluber constrictor. This moderately large non-venomous snake, with the largest individuals approaching two metres in length, is a widespread inhabitant of open habitats such fields, brushland or open woodlands. Its distribution is centred over much of the continental United States, being found in most regions except much of the arid south-west. Outside the United States, it has a very patchy distribution in southernmost Canada, Mexico and northern Central America. Most recent authors treat it as the sole species in the genus Coluber; other species historically assigned to this genus from across the Holarctic region now being treated as separate. These include the North American whip snakes of the genus Masticophis, believed to the closest relatives of the racer (Myers et al. 2017).

Southern black racer Coluber constrictor priapus, copyright Peter Paplanus.

Adult racers are generally uniformly dark in coloration dorsally, with a lighter-coloured venter, though juveniles have a blotchy checkered pattern (Fitch 1963). The exact shade varies across the species' range and a number of subspecies have been recognised such as the blue racer Coluber constrictor foxii and the northern black racer C. c. constrictor. In general, individuals are darker towards the east and north, and lighter towards the west and south. Wilson (1978) listed eleven subspecies of C. constrictor whereas a phylogeographic study of the species by Burbrink et al. (2008) identified six major lineages. As well as coloration, members of these lineages may differ in factors such as behaviour or genital morphology, and future studies may see them elevated to the rank of separate species.

Blue racer Coluber constrictor foxii, copyright Peter Paplanus.

The natural history of Coluber constrictor was reviewed in detail by Fitch (1963). As the vernacular name of 'racer' suggests, Coluber constrictor is a fast mover. Its diet contains a mixture of small vertebrates, such as frogs, lizards and small mammals, and large invertebrates such as grasshoppers, crickets and caterpillars. Foraging individuals often hold the front end of the body raised above the ground. Despite their species name, racers do not kill their prey by constriction. Instead, they mostly capture prey by darting forward quickly and grabbing it, often swallowing prey live. Fitch recorded one occasion when he observed a racer in the process of subduing a large skink. While the snake was swallowing its prey, Fitch attempted to capture it. The racer disgorged the skink, and both snake and lizard escaped the scene. Diet may vary with size, with smaller individuals taking a higher proportion of invertebrates, but also varies with range. Populations in the west may primarily feed on insects whereas others may almost exclusively take vertebrates. The northern black racer of the northeastern United States is the most inclined of the subspecies to feed on other snakes. Cannibalism is not unknown; at least one author recorded observing it among broods raised in captivity. In one case, two young racers latched onto a single lizard. One of them successfully downed the lizard, and then also continued on to devour the snake attached to the other end, despite the swallowed snake being nearly as large as its swallower.

Eastern yellow-bellied racer Coluber constrictor flaviventris, copyright David Sledge.

During winter, racers hibernate in crevices and hollows among rocks. Preferred hibernation locations are often at the top of hills, away from their usual hunting sites. Mating and egg-laying occurs shortly after emergence with the peak of egg-laying being in early June (Rosen 1991). Racers, particularly the large northern black, may become more aggressive during this period. Eggs are buried shallowly, in loose soil or under litter, though females may take advantage of abandoned mammal burrows to provide a more secure location. As with other snakes, laying seems to be a matter of pump and dump; I didn't come across any references to females protecting clutches. After hatching, males take about a year to reach sexual maturity whereas the larger females take about two years. Fitch (1963) reports encountering the same individuals over the course of several years (recognisable by their bearing the scars of prior collection of scale samples). Nevertheless, the majority of racer hatchlings do not survive their first summer. Few get the opportunity to seek out shelter for their winter's sleep.

REFERENCES

Burbrink, F. T., F. Fontanella, R. A. Pyron, T. J. Guiher & C. Jimenez. 2008. Phylogeography across a continent: the evolutionary and demographic history of the North American racer (Serpentes: Colubridae: Coluber constrictor). Molecular Phylogenetics and Evolution 47: 274–288.

Fitch, H. S. 1963. Natural history of the racer Coluber constrictor. University of Kansas Publications, Museum of Natural History 15 (8): 351–468.

Myers, E. A., J. L. Burgoon, J. M. Ray, J. E. Martínez-Gómez, N. Matías-Ferrer, D. G. Mulcahy & F. T. Burbrink. 2017. Coalescent species tree inference of Coluber and Masticophis. Copeia 105 (4): 640–648.

Wilson, L. D. 1978. Coluber constrictor Linnaeus. Catalogue of American Amphibians and Reptiles 218: 1–4.

The Lipinia Skinks

For a long time in the history of herpetology, many of the smaller skinks in the Asia-Pacific region were combined in a single sprawling genus Lygosoma. For an equally long time, this state of affairs had been considered unsatisfactory, with not much defining Lygosoma other than "it ain't anything else". However, it was until the mid-20^th Century that researchers began reliably identifying recognisable subgroups within the lygosomine mass that they could carve off into separate genera. One of these ex-Lygosoma isolates is now recognised as the genus Lipinia.

Yellow-striped tree skink Lipinia vittigera, copyright Sergey Yeliseev.

Lipinia is a genus of about thirty known species of small skinks (reaching at most a snout-vent length of nearly six centimetres) found in south-east Asia and the islands of the tropical Pacific. Even now, the genus remains difficult to clearly define with its species having a fairly unspecialised habitus. It belongs to a group of genera in which the lower eyelid usually has a transparent window, presumably allowing the skink to retain some modicum of vision even with its eyes closed. Within this cluster of genera, distinguishing features of Lipinia include smooth scales, slightly to strongly expanded subdigital lamellae, and the loss of the postorbital bone. They often show a strongly striped dorsal pattern with a pale mid-dorsal stripe anteriorly (Shea & Greer 2002; Poyarkov et al. 2019). Species are diurnal and may be arboreal, semi-arboreal or terrestrial in habits (terrestrial species are quite reclusive). The clutch of eggs laid by females is usually quite small, two at most (one for each oviduct). In a number of species, one of the oviducts is vestigial and only a single egg is laid.

Moth skink Lipinia noctua, from Ecology Asia.

The most widespread species in the genus is the moth skink Lipinia noctua, found over a range extending from eastern Indonesia to the Pitcairn Islands (I have no idea why it is called a 'moth skink'). It is believed to have originally been native to New Guinea before spreading over its current range in association with humans, an inadvertent stowaway in ocean-crossing boats and canoes*. It was doubtless assisted in this spread by its ovoviviparous habit: that is, rather than laying eggs in the manner of related species, eggs are retained in the mother's body until young can be born free-living. So thorough was the transmission of this little skink by humans that its genetics have been investigated in relation to the settlement of the islands (Austin 1999). They support a picture of rapid eastward expansion; when Polynesian explorers discovered the islands that would eventually become their people's home, the skinks were there discovering them too.

*A note on terminology: though the manned craft used by the initial settlers of the Pacific islands are commonly referred to in English as 'canoes', these were not just the small craft many people associated with the term. Polynesian waka/vaka/etc. (the exact term, of course, varies linguistically) can be sizable ships, twenty metres or more in length, with commensurately sizable crews. Those used for long ocean crossings would have double hulls or outriggers and would largely be propelled by sail rather than oars.

REFERENCES

Austin, C. C. 1999. Lizards took express train to Polynesia. Nature 397: 113–114.

Poyarkov, N. A., Jr, P. Geissler, V. A. Gorin, E. A. Dunayev, T. Hartmann & C. Suwannapoom. 2019. Counting stripes: revision of the Lipinia vittigera complex (Reptilia, Squamata, Scincidae) with description of two new species from Indochina. Zoological Research 40 (5): 358–393.

Shea, G. M., & A. E. Greer. 2002. From Sphenomorphus to Lipinia: generic reassignment of two poorly known New Guinea skinks. Journal of Herpetology 36 (2): 148–156.

Pond Turtles of Asia

In an earlier post on this site, I discussed some members of the tortoise family Testudinidae. In popular depictions, the terrestrial tortoises are commonly associated with arid deserts and Mediterranean climes, where rains are sparse and water bodies few. But tortoises are exceptional in this regard among the order Testudines, members of which are more generally aquatic. As an example, consider the closest relatives of the Testudinidae, the pond turtles of the Geoemydidae.

Southern river terrapin Batagur affinis, copyright Eng Heng Chan.

Members of the Geoemydidae (historically referred to in many publications as the Bataguridae) are commonly referred to as the Asiatic pond turtles and it is in southern and eastern Asia that they are most diverse. However, they are also found in Europe and northern Africa, and a single genus Rhinoclemmys is found in northern South America. About 65 or 70 species are recognised in the family, making them quite diverse as turtles go. Many geoemydids are colorfully patterned and some can reach reasonably large sizes. The northern river terrapin Batagur baska, for instance, may grow up to two feet in length and close to twenty kilograms in weight.

Black-breasted leaf turtle Geoemyda spengleri, copyright Heather Paul.

A phylogenetic analysis of the Geoemydidae by Hirayama in 1984 lead to the suggested division of the geoemydids between two subfamilies, the Geoemydinae and Batagurinae. The two subfamilies were primarily distinguished by the extent of development of the secondary palate and hence the width of their jaws, with the Batagurinae having a more extensive secondary palate and broader jaws than the Geoemydinae. Batagurines were also generally more aquatic and more herbivorous than the semi-terrestrial, more omnivorous geoemydines. Hirayama also suggested that the geoemydines might be paraphyletic to the Testudinidae (Spinks et al. 2004). More recent phylogenetic analyses have supported geoemydid monophyly, placing them as sister rather than ancestral to Testudinidae (Spinks et al. 2004; Guillon et al. 2012). They have also supported a clade including the majority of Hirayama's batagurines, excluding only the genus Siebenrockiella. However, Hirayama's geoemydines have not been supported as monophyletic; instead, the Neotropical Rhinoclemmys represents the sister group of the Old World geoemydids. This is not entirely surprising; comparison with other turtle families indicates that the narrow-jawed 'geoemydine' condition is primitive among turtles. As a result, the Batagurinae is no longer recognised as a distinct subfamily.

Golden coin turtle Cuora trifasciata, copyright Torsten Blanck.

Unfortunately, the Asian species of pond turtle are currently facing a conservational crisis. The majority of species are regarded as endangered, many critically so, due to threats such as habitat loss and hunting for food. Some species, most notably the golden coin turtle Cuora trifasciata, are targeted for use in Chinese medicine because why wouldn't they be? Many geoemydid species have been bred in captivity but this is also not without issues. In the case of the golden coin turtle, there is the all-too-common issue that even when farmed individuals are available they are not seen as being as valuable as wild-caught specimens. Also, because the gender of hatchlings is determined by incubation temperature, farmed clutches are skewed almost entirely towards females, requiring the continued harvesting of wild males. Many geoemydid species hybridise readily. During the period from 1984 to 1997, no less than thirteen new species of geoemydid were described from China, most on the basis of specimens purchased from a single pet dealer in Hong Kong (Parham et al. 2001). Many of these specimens were of uncertain origin. Searches for further specimens in reported localities for some species failed to provide results, and queries to local residents revealed that they had never seen such turtles. At least some of these supposed new species have since been identified as hybrids, probably produced in captivity, and the status of others remains questionable.

REFERENCES

Guillon, J.-M., L. Guéry, V. Hulin & M. Girondot. 2012. A large phylogeny of turtles (Testudines) using molecular data. Contributions to Zoology 81 (3): 147–158.

Parham, J. F., W. B. Simison, K. H. Kozak, C. R. Feldman & H. Shi. 2001. New Chinese turtles: endangered or invalid? A reassessment of two species using mitochondrial DNA, allozyme electrophoresis and known-locality specimens. Animal Conservation 4: 357–367.

Spinks, P. Q., H. B. Shaffer, J. B. Iverson & W. P. McCord. 2004. Phylogenetic hypotheses for the turtle family Geoemydidae. Molecular Phylogenetics and Evolution 32: 164–182.

All the Skinks of the Rainbow

Breeding male southern rainbow skink Carlia tetradactyla, copyright Will Brown.

Australia is home to a diverse and distinctive array of reptiles, most of which are unique to the continent. Perhaps the most famous of these are its venomous snakes and gigantic crocodiles, but the continent also possesses its fair share of lizards. Among these are the subjects of today's post, the rainbow skinks of the genus Carlia.

Carlia is primarily a genus of the north of Australia, particularly northern Queensland. They are moderately-sized skinks, with a snout-to-vent length of up to seven centimetres (indicating a total length of about half a foot). The vernacular name 'rainbow skink' refers to the bright colours, red, green, blue and/or black, exhibited by males of this genus during the breeding season. Females (and non-breeding males) are duller in coloration and commonly have a white stripe along the side of the body (Dolman & Hugall 2008). Only one of the more than twenty Australian species, the southern rainbow skink C. tetradactyla, is found in the southern half of the continent (specifically in a band from southernmost Queensland to northern Victoria). More than a dozen other species are found in New Guinea and neighbouring islands of eastern Indonesia; one species, C. peronii, is found on the island of Timor. Many Carlia species are difficult to distinguish without close examination and new ones continue to be described on a regular basis.

Closed-litter rainbow skink Carlia longipes (perhaps a non-displaying male?), copyright Greg Schechter.

Carlia can be easily distinguished from most other skink genera in the region by counting the toes, of which there are four on the forefoot and five on the hind foot (Storr 1974). Some authors have included all such Australo-Papuan skinks in this genus, but following a molecular phylogenetic analysis Dolman & Hugall (2008) recognised three genera of four-toed skinks in Australia: Carlia and the two smaller genera Lygisaurus and Liburnascincus. Lygisaurus species are generally more slender than Carlia and often have smaller legs. Liburnascincus includes three species of large skinks with sprawling legs found living around rocks. Both these genera lack the contrast in coloration between the sexes found in Carlia; at most, male Lygisaurus will become reddish around the head or tail.

Male rainbow skinks maintain territories from which they will vigorously exclude other males; a male may hold the same territory for several years (Langkilde et al 2004). Breeding males display themselves by flattening the body and tilting to one side, in order to optimise their apparent size and strikingness. Of the two Carlia species for which behaviour has been studied in detail, the black-throated rainbow skink C. rostralis is most likely to perform this display to other males, presumably as an act of intimidation. The lined rainbow skink C. jarnoldae, on the other hand, is more likely to perform its tilting display in the presence of a female (Langkilde et al. 2003). They may also display in this way towards predators, presumably to make themselves appear less digestible. Other displays performed by rainbow skinks include moving the head to display the coloration of the throat, or flicking the tail (this latter appears to be primarily a defensive display, being performed in the presence of predators or encroaching males). Langkilde et al. (2003) also found rainbow skinks to 'play dead' when captured, a rare behaviour in skinks (though known from other lizards).

Admiralty brown skink Carlia ailanpalai, from Lardner et al. (2013). This species lacks the sexual dichromatism of other Carlia species.

Rainbow skinks are also present in islands of western Micronesia, where they have been introduced by human activity. They were first recognised in Micronesia in the early 1960s, subsequently becoming abundant and seemingly supplanting native skinks in more disturbed areas. On Guam, they are also believed to have played a part in the spread of the brown tree snake Boiga irregularis: the healthy population of introduced skinks provided a reliable food source for the introduced snake. Because of the aforementioned difficulties in Carlia taxonomy, the exact identity of Guam's 'curious skink' was uncertain for many years though it was certainly part of the New Guinean 'Carlia fusca' group. A molecular analysis of Micronesian Carlia by Austin et al. (2011) confirmed that the species in question was the Admiralty brown skink C. ailanpalai but also found that skinks from different parts of Micronesia where connected genetically to different parts of the New Guinean archipelago. Rainbow skinks from Guam, for instance, were related to populations on Manus and New Ireland, whereas Palau skinks were more closely akin to New Britain residents. Austin et al. noted a correlation between the sources of each of the inferred separate invasions in Guam, Palau and the Northern Marianas and troop movements during World War II. While machinery and equipment was being transported to Micronesia for use in the Pacific theatre of war, skinks were apparently hitching rides. Alternatively, some could have reached Micronesia with equipment being returned to permanent military bases from New Guinea after the war's close. The resulting seed populations would have presumably been small, explaining why it took another twenty years or so before they were noticed.

REFERENCES

Austin, C. C., E. N. Rittmeyer, L. A. Oliver, J. O. Andermann, G. R. Zug, G. H. Rodda & N. D. Jackson. 2011. The bioinvasion of Guam: inferring geographic origin, pace, pattern and process of an invasive lizard (Carlia) in the Pacific using multi-locus genomic data. Biol. Invasions 13: 1951–1967.

Dolman, G., & A. F. Hugall. 2008. Combined mitochondrial and nuclear data enhance resolution of a rapid radiation of Australian rainbow skinks (Scincidae: Carlia). Molecular Phylogenetics and Evolution 49: 782–794.

Langkilde, T., L. Schwarzkopf & R. Alford. 2003. An ethogram for adult male rainbow skinks, Carlia jarnoldae. Herpetological Journal 13: 141–148.

Langkilde, T., L. Schwarzkopf & R. A. Alford. 2004. The function of tail displays in male rainbow skinks (Carlia jarnoldae). Journal of Herpetology 39 (2): 325–328.

Storr, G. M. 1974. The genus Carlia (Lacertilia: Scincidae) in Western Australia and Northern Territory. Records of the Western Australian Museum 3 (2): 151–165.

Look Away: Chameleons

Mediterranean chameleon Chaemaeleo chamaeleon, copyright Benny Trapp.

For my next post, I drew the topic of 'Chamaeleonidae', the chameleons*. This left me with a bit of a quandary because Darren Naish over at Tetrapod Zoology covered the chameleons recently in his usual exhaustive style in a series of three posts (part 1, part 2, part 3). I was somewhat tempted to simply tell you all to go read Darren's posts and consider my work done, but let's see if I can dig up anything he left out. You should still go read Darren's posts anyway.

*I'm using Chamaeleonidae in the restricted sense here, the one that will probably be familiar to most people. Some authors have suggested expanding Chamaeleonidae to also include members of the dragon family Agamidae, following the recognition that the latter in its traditional sense is paraphyletic. This suggested re-classification does not appear to have caught on widely.

Chameleons are certainly one of the most distinctive of lizard groups, with their clasping zygodactylous foot structure, periscopic eyes and projectile tongues. They are most diverse in Africa, with only the genus Chamaeleo extending into southern Europe (just barely) and south-western Asia to India. The name is Greek in origin and can be read as 'ground lion'; presumably someone thought that the European chameleon's hissing threat display looked a bit like an imitation of a lion's roar. The most familiar chameleons are primarily arboreal, creeping slowly along branches, but the smaller leaf chameleons are terrestrial and this may represent the ancestral habit for the family (Tolley et al. 2013).

The tiny leaf chameleons, some of which are less than two centimetres long when mature, have a morphotype that is best described as 'completely daft'. This is a bearded leaf chameleon Rieppeleon brevicaudatus, copyright Fridtjof Busse.

Chameleons are most famous, of course, for their colour-changing abilities. Most of you will probably be aware that said colour changes are related to social signalling rather than camouflage... except that, in a sense, they are related to camouflage too, because a chameleon that drops its signal colours becomes a lot better concealed. The colour is managed through guanine crystals in the integument: changing the distance between crystals changes the wavelength reflectance of the light. The degree to which chameleons change colour varies from species to species. Some merely change their overall shade from darker to lighter (which I suspect may be related to body temperature regulation as much as anything else) whereas others reveal bright lurid patterns of flouro stripes and blotches. I haven't come across any indications whether there are any chameleon species that don't change colour at all, nor do I know what the distribution of colour-changing is like in other lizard groups. I do have a vague memory that thorny devils Moloch horridus (belonging to the related Agamidae) become duller in colour when they are colder, but I'm not certain about this. And I'm going to cite one recent paper on colour signalling in chameleons by Ligon (2014) purely for its epic title: "Defeated chameleons darken dynamically during dyadic disputes to decrease danger from dominants".

Male Malagasy giant chameleon Furcifer oustaleti, copyright Drägüs.

Because of their Africa-centric distribution, chameleons have generally been assumed to have originated on that continent. The fossil record of chameleons is pretty abysmal (probably because they tend not to frequent habitats conducive to fossilisation) though Miocene fossils do indicate a wider distribution in Europe during warmer times. The European fossil species are included in the genus Chamaeleo, though I'm not sure if this indicates a close relationship with the modern European species or is simply an artefact of when most larger chameleons were included in this genus. The eastern islands of Africa are home to three independent clades of chameleons: the leaf chameleons Brookesia and a clade of larger chameleons containing the genera Furcifer and Calumma in Madagascar, and the Seychelles endemic Archaius tigris. Though Brookesia represents the sister clade to the remaining chameleons, current directions make it likely that each of these clades represents a dispersal from African ancestors* (it is unlikely that chameleons are old enough for the clades to have been separated by plate tectonics). One announcement that was recent enough to have missed Darren Naish's posts (though it made it into the ensuing comments) was the discovery of a close relative of the chameleons preserved in Burmese amber from the Cretaceous period. This specimen (which has not yet been given a scientific name beyond the collection number of JZC Bu154) is, at less than 11 mm long, probably a very young juvenile, though even when adult it may have only been in the size range of the tiny Brookesia leaf chameleons. JZC Bu154 retains a number of ancestral features relative to modern chameleons, such as a non-clasping foot structure, so if it is related to the chamaeleonids it is undoubtedly in the stem group (Daza et al. 2016). As such, its Burmese provenance does not contradict an African origin for crown-group chameleons.

*At least one chameleon has dispersed in the opposite direction by other means: thanks to human transportation, the Malagasy giant chameleon Furcifer oustaleti established a small population in the vicinity of Nairobi, though it appears doubtful whether this still survives. Two other species, the veiled chameleon Chamaeleo calyptratus and Jackson's chameleon Trioceros jacksonii, native to the Arabian Peninsula and east Africa, respectively, have been introduced to some parts of the United States, most notably Hawaii.

REFERENCES

Daza, J. D., E. L. Stanley, P. Wagner, A. M. Bauer, & D. A. Grimaldi. 2016. Mid-Cretaceous amber fossils illuminate the past diversity of tropical lizards. Science Advances 2: e1501080.

Tolley, K. A., T. M. Townsend & M. Vences. 2013 Large-scale phylogeny of chameleons suggests African origins and Eocene diversification. Proceedings of the Royal Society B 280: 20130184.

Tortoise Sorting

Indian star tortoise Geochelone elegans, copyright P. G. Palmer.

As a whole group, the 'true' tortoises of the family Testudinidae are easily recognised, with a usually terrestrial habitus (though at least one species, the serrated hinge-back tortoise Kinixys erosa, is a capable swimmer), columnar legs with short heavy-clawed feet, and a relatively high carapace. But relationships within the tortoises have seen a bit of shuffling around in recent years, and nowhere has that shuffling been more obvious than in the genus Geochelone.

Many of you may know Geochelone as the genus including the giant tortoises of the Galapagos Islands and islands in the Indian Ocean, as well as species such as the radiated tortoise G. radiata of Madagascar and the geometric tortoise G. geometrica of South Africa. At its broadest, about half the world's tortoise species have been included in Geochelone. However, the genus has always been poorly defined, marked by its 'primitive' skull (Gerlach 2001), and the lack of features of other tortoise genera such as the plastral hinge of the Palaearctic Testudo species, or the rear-carapace hinge of African Kinixys species. For the most part, Geochelone was simply a home for the bigger tortoises.

Burmese star tortoise Geochelone platynota, copyright Kalyar Platt.

So it is hardly surprising that phylogenetic studies, whether morphological (Gerlach 2001) or molecular (Fritz & Bininda-Emonds 2007), have failed to support a broad Geochelone as a monophyletic group. As a result, recent authors have advocated recognising a number of separate genera: the Galapagos tortoises belong to the genus Chelonoidis, the Seychelles giant tortoises to Aldabrachelys (as confirmed by ICZN 2013), the radiated tortoise to Astrochelys and the geometric tortose to Psammobates. From being the largest recognised tortoise genus, Geochelone has been cut down to a mere two or three species. These are the Indian star tortoise Geochelone elegans, the Burmese star tortoise G. platynota, and, maybe, the African spurred tortoise G. sulcata.

The Indian and Burmese star tortoises are two very similar species that get their names from their colour pattern, with radiating star-like markings on the carapace. The individual scutes of the carapace bulge outwards, giving the animal an overall lumpy appearance. They are both medium-sized tortoises, growing to over 30 cm in length. The Indian star tortoise Geochelone elegans is widespread in dry habitats in India, Pakistan and Sri Lanka, though conservation concerns have been raised about the extent of harvesting of wild tortoises for food and the exotic pet trade. The Burmese star tortoise G. platynota, on the other hand, is critically endangered, having been almost wiped out from its original range in the central dry zone of Burma. As long ago as 1863, Edward Blyth (who, offhand, sported one heck of an impressive beard) was complaining that specimens were difficult to find due to the local people's fondness for eating them (Platt et al. 2011).

African spurred tortoise Geochelone sulcata, copyright Chris Mattison.

The African spurred tortoise Geochelone sulcata is found across the southern part of the Sahara Desert and the Sahel. It is a particularly large tortoise, growing to over 80 cm (Swingland & Klemens 1989); in fact, it is the largest tortoise that is not found on oceanic islands. Spurred tortoises dig burrows that can reach up to 3.5 m in length in which to avoid the full heat of the day. This species is placed by some authors in its own genus Centrochelys, cutting Geochelone down to just the two Asian star tortoises. Molecular studies place G. sulcata as the sister taxon to the Asian species (Fritz & Bininda-Emonds 2007), but they have not been associated in morphological studies. Though widespread, the African spurred tortoise is regarded as vulnerable due to the degradation of its habitat. Concern has also been raised, again, about the collection of wild individuals for the pet trade.

REFERENCES

Fritz, U., & O. R. P. Bininda-Emonds. 2007. When genes meet nomenclature: tortoise phylogeny and the shifting generic concepts of Testudo and Geochelone. Zoology 110: 298-307.

Gerlach, J. 2001. Tortoise phylogeny and the ‘Geochelone’ problem. Phelsuma 9 (Supplement A): 1-24.

ICZN. 2013. Opinion 2316: Testudo gigantea Schweigger, 1812 (currently Geochelone (Aldabrachelys) gigantea; Reptilia, Testudines): usage of the specific name conserved by maintenance of a designated neotype, and suppression of Testudo dussumieri Gray, 1831 (currently Dipsochelys dussumieri). Bulletin of Zoological Nomenclature 70 (1): 61-65.

Platt, S. G., T. Swe, W. K. Ko, K. Platt, K. M. Myo, T. R. Rainwater & D. Emmett. 2011. Geochelone platynota (Blyth 1863)—Burmese star tortoise, kye leik. Chelonian Research Monographs 5: 057.1-057.9.

Swingland, I. R., & M. W. Klemens (eds). 1989. The conservation biology of tortoises. Occasional Papers of the IUCN Species Survival Commission 5.

Dragons in a Desolate Land

Ring-tailed dragon Ctenophorus caudicinctus, from here.

The comb-bearing dragons of the genus Ctenophorus are an assemblage of 28 (and counting!) species of medium-sized lizards found around Australia. Darren Naish has recently been giving an overview of the Australian dragons; you can read what he's already said about Ctenophorus here. I'd suggest reading that first, then coming back here.

Species of Ctenophorus are distinguished from other dragons by the presence of a row of tectiform (roof-shaped) scales running from behind the nostrils under the eyes, though in some species this row is only weakly pronounced (Melville et al. 2008). In most species, the tympanum (ear-drum) is exposed, though a few species have it covered over. I'm personally familiar with one species of Ctenophorus, the ring-tailed dragon C. caudicinctus. Where we've been doing fieldwork on Barrow Island, ring-tailed dragons are a common site perched on termite mounds or larger rocks, invariably just one dragon to a rock, monitoring the surrounding territory for food or mates. Not all Ctenophorus species engage in such behaviour: the species have been divided between three groups depending on whether they prefer rocky habitats, whether they prefer sandy habitats and use tufts of spinifex and other vegetation for cover, or whether they shelter in burrows. Phylogenetic analysis suggests that the burrowing habit was ancestral for the genus; rock-dwelling or scrub-dwelling habits may have each evolved more than once within Ctenophorus, though the possibility cannot be entirely ruled out that they may characterise monophyletic groups (Melville et al. 2001). These differences in ecology also correlate with morphological differences: rock-dwelling species have dorsoventrally flattened heads, while the scrub-dwelling species are long-legged and cursorial.

Military dragon Ctenophorus isolepis, a sand-dwelling species associated with spinifex, photographed by Stewart Macdonald.

While some species of Ctenophorus are widespread, others are far more restricted in range. Ctenophorus caudicinctus, for instance, is found across most of northern Western Australia and the Northern Territory, but Butler's dragon* C. butleri is restricted to coastal sand dunes between Shark Bay and Kalbarri in Western Australia (Cogger 2014). The most recently described species to date, the Barrier Range dragon C. mirrityana, is known from two locations about 100 km apart in western New South Wales (McLean et al. 2013). And it possibly does say something that new species continue to be described even in this not inconspicuous genus.

*Or should that be 'Butlers' dragon', as it was apparently named after both Harry and Margaret Butler?

Lake Eyre dragon Ctenophorus maculosus, photographed by Rune Midtgaard.

Perhaps the most hard-core of the comb-bearing dragons is the Lake Eyre dragon Ctenophorus maculosus, a specialised inhabitant of dry salt lakes in South Australia. This is a spectacularly harsh environment: searing hot sun, often at temperatures above 40°, beating down on a crust of crystallised salt. Few other animals can survive there without spontaneously combusting. The dragons protect themselves from the head by burrowing into the layer of unconsolidated sand beneath the salt-crust; Pedler & Neilly (2010) discovered one female with its head protruding from a burrow with an entrance too small for its body, and suggested that she must have gotten there by 'swimming' through the sand. The Lake Eyre dragons feed on ants such as Melophorus (themselves no slouch in the hard-core stakes) or other insects that have become stranded on the salt-pan. When the lake becomes filled with water (as it does about once a decade or so), the dragons are forced to flee into the habitats surrounding the lake shores and wait for the flood to clear. Two Western Australian species, the claypan dragon Ctenophorus salinarum and the Lake Disappointment dragon C. nguyarna, are also associated with salt-pans, but they do not have quite the level of specialisation of the Lake Eyre dragon.

REFERENCES

Cogger, H. G. 2014. Reptiles and Amphibians of Australia, 7th ed. CSIRO Publishing: Collingwood.

McLean, C. A., A. Moussalli, S. Sass & D. Stuart-Fox. 2013. Taxonomic assessment of the Ctenophorus decresii complex (Reptilia: Agamidae) reveals a new species of dragon lizard from western New South Wales. Records of the Australian Museum 65 (3): 51-63.

Melville, J., L. P. Shoo & P. Doughty. 2008. Phylogenetic relationships of the heath dragons (Rankinia adelaidensis and R. parviceps) from the south-western Australian biodiversity hotspot. Australian Journal of Zoology 56: 159–171.

Melville, J., J. A. Shulte II & A. Larson. 2001. A molecular phylogenetic study of ecological diversification in the Australian lizard genus Ctenophorus. Journal of Experimental Zoology 291: 339-353.

Pedler, R. & H. Neilly. 2010. A re-evaluation of the distribution and status of the Lake Eyre dragon (Ctenophorus maculosus): an endemic South Australian salt lake specialist. South Australian Naturalist 84 (1): 15-29.

Obama's Lizard? Not So Fast

Left dentary of a currently unnamed lizard from the latest Cretaceous, from Longrich et al. (2012).

Yeah, this is a pretty petty point, but what would this site be if it didn't pertain to pedantry?

In the last week of last year, a paper was published in the Proceedings of the National Academy of Sciences of the USA on lizards in the latest Cretaceous and Palaeocene of North America (Longrich et al. 2012). The paper garnered itself a certain degree of media coverage because the authors chose to name a new genus after the current president of the United States, Barack Obama: see here and here, for instance. Because I was away for Christmas at the time, I've only just gotten the opportunity to look at the actual paper.

One thing immediately sprung out at me (and those of you familiar with my dribblings have probably already guessed what I'm about to say): this genus has not been validly published. The description is not in the body of the paper itself, it is in the online supplementary info. The printed section of the paper does include very brief diagnostic comments, but does not include an explicit designation of type material. Despite the recent decision by the ICZN allowing electronic-only publication, the supplementary info in Longrich et al. (2012) does not meet the requirements for valid electronic publication. It has not been registered with ZooBank, and it does not contain any indication of having been registered.'Obamadon gracilis' is hence an unavailable name, as are the other described taxa 'Pariguana lancensis' and 'Socognathus brachyodon'. Sorry. Once again, the space-saving requirements of a 'high-tier' science publication has shafted nomenclature.

I'd also be interested if anyone has comments on another potential problem. The supplementary info for Longrich et al. (2012) has been presented as a Microsoft Word document. I've no wish to argue the merits or otherwise of Microsoft Word per se—it's the word processing programme I generally use myself—but the ICZN requires that electronic publications be produced using a method that ensures 'widely accessible electronic copies with fixed content and layout'. PDF is not actually required, but is mentioned as an example of a format fulfilling this requirement. What about Word, though? Do you think a Word document can be regarded as 'fixed', or do you think that it is too easily altered after the fact?

REFERENCE

Longrich, N. R., B.-A. S. Bhullar & J. A. Gauthier. 2012. Mass extinction of lizards and snakes at the Cretaceous–Paleogene boundary. Proceedings of the National Academy of Sciences of the USA 109 (52): 21396-21401.

Anole, Anole, Anole, Anole

Brown anole Anolis sagrei, a species that has become widely distributed in the Caribbean and also in Florida, photographed by Ianaré Sévi.

Today, the watchword is Anolis. Anolis, the anoles, is an enormous assemblage of lizards found in warmer parts of the Americas: with well over 350 species, it is the largest genus generally recognised among the amniotes. Species within the genus have received a lot of attention for their ecological diversity. In some parts of Cuba, there may be fourteen or fifteen Anolis species found in a single locality, each occupying their own distinct niche (Thomas et al. 2009). Examples of anole ecotypes include crown-giants, up to and above half a metre in length, that live in the forest canopy; slender, short-legged twig anoles, that creep along narrow branches; and also slender, but much longer-legged, grass-bush anoles that are found in dense undergrowth (Losos 2009).

The Gorgona Island anole Anolis gorgonae, photographed by Luke Mahler.

Some species of anole have even been the subjects of direct experimental studies on evolutionary processes. Hind limb length in different anole species has been observed to correlate with substrate usage: those species that prefer wider branches have longer hind legs than those utilising smaller branches. In order to test whether natural selection played a direct part in determing leg length, the brown anole Anolis sagrei was introduced in 1977 and 1981 to fourteen small islands, of varying vegetation type, in the Bahamas that had been previously uninhabited by anoles. After ten years had passed, measurements were taken of anoles on each of the islands where they had persisted and compared back to the source population. It was demonstrated that (a) many of the experimental populations were statistically significantly different from the source population after ten years, and (b) the degree of difference between populations was correlated with the degree of difference in the vegetation oof the two localities (Losos et al. 1997). However, later studies of brown anoles in the laboratory reared in cages with different-sized available substrates indicates that leg length in anoles is, to some extent, phenotypically plastic depending on environmental pressures (Losos et al. 2000). Nevertheless, a selective component to variation was supported by experiments involving translocation between montane and lowland habitats of the Dominican anole Anolis oculatus (Thorpe et al. 2005).

The Hispaniolan hopping anole Anolis barbouri, a species long included in a separate genus Chamaelinorops, photographed by Rob Op 't Veld.

Being such a huge genus, it is not surprising that attempts have been made to break Anolis down to more manageable units, with varying success. Hillis (1996, as quoted in Poe 2004) described anoles as "a huge group where all the species look virtually the same": a quite unfair aspersion (see above) but nevertheless expressive of the difficulties in establishing relationships between species (ecological convergence, for instance, is rampant). Anoles have been divided into two major subgroups, the Alpha and Beta anoles, on the basis of the presence (Beta) or (Absence) of transverse processes on the caudal vertebrae, and some authors have proposed recognising the Beta anoles as a separate genus Norops. Recent phylogenetic analyses have agreed that the Beta anoles are monophyletic, but nested deeply in the Alpha anoles (Poe 2004; Nicholson et al. 2005). Because of difficulties in defining usual subgroups among the Alpha anoles, recent authors have therefore continued to maintain a super-sized Anolis*.

*Which just highlights again how the binomial system can force false dichotomies. The nested position of 'Norops' within 'Anolis' means that one must either (a) subdivide Anolis, perhaps impractically, (b) sink Norops and obscure that group's distinctiveness, or (c) recognise a paraphyletic Anolis, obscuring the closer relationships between some Anolis and Norops species. Three suboptimal choices, but you must pick one because you can't have species without genera. Surely it would be better overall if one could just sidestep the question by recognising a clade Norops within a clade Anolis?

The Cuban false chamaeleon Anolis chamaeleonides, another species previously in a separate genus (Chamaeleolis), photographed by Lubomir Hlasek.

Also of interest are the biogeographic patterns within Anolis that phylogenetic analysis has revealed. Both the Alpha and Beta anoles have species on the Caribbean islands as well as continental South America (a little less than half the currently recognised Anolis species are found on Caribbean islands). The South American Alpha anoles form a clade (sometimes recognised as a separate genus Dactyloa) that, together with the Anolis roquet group of species found in the southern Lesser Antilles, forms the sister group of most or all of the remaining Anolis species (Poe 2004; Nicholson et al. 2005). Most lineages within the remaining anoles are Caribbean; the South American Beta anoles also form a single clade whose nested position among Caribbean taxa indicates a relatively rare demonstrable case of dispersal from an island to a continent (as opposed to the other way around, the more usual expectation in biogeography). Most of the Greater Antillean islands are home to multiple lineages of anoles; the exception is Jamaica which, except for the recently arrived Anolis sagrei, is inhabited by a single clade of Beta anoles (the sister group to the South American Beta anoles). The Carolina anole Anolis carolinensis of the southeast United States is also of Caribbean origin, being nested among a clade of Cuban species. It is worth noting that this last continental colonisation is, in a way, currently repeating itself: though probably brought by human agents, a number of Caribbean anole species are now known in the wild from Florida.

REFERENCES

Losos, J. B. 2009. Lizards in an Evolutionary Tree: Ecology and adaptive radiation of anoles. University of California Press.

Losos, J. B., D. A. Creer, D. Glossip, R. Goellner, A. Hampton, G. Roberts, N. Haskell, P. Taylor & J. Ettling. 2000. Evolutionary implications of phenotypic plasticity in the hindlimb of the lizard Anolis sagrei. Evolution 54 (1): 301-305.

Losos, J. B., K. I. Warheit & T. W. Schoener. 1997. Adaptive differentiation following experimental island colonisation in Anolis lizards. Nature 387: 70-73.

Nicholson, K. E., R. E. Glor, J. J. Kolbe, A. Larson, S. B. Hedges & J. B. Losos. 2005. Mainland colonization by island lizards. Journal of Biogeography 32: 929-938.

Poe, S. 2004. Phylogeny of anoles. Herpetological Monographs 18: 37-89.

Thomas, G. H., S. Meiri & A. B. Phillimore. 2009. Body size diversification in Anolis: novel environment and island effects. Evolution 63 (8): 2017-2030.

Thorpe, R. S., J. T. Reardon & A. Malhotra. 2005. Common garden and natural selection experiments support ecotypic differentiation in the Dominican anole (Anolis oculatus). American Naturalist 165 (4): 495-504.

The Ornithocheirids: Misunderstood Giants

The original specimen of Ornithocheirus simus, from Joseph Dinkel.

The pterosaurs of the Ornithocheiridae that lived between the Early and mid-Cretaceous were not the largest pterosaurs to ever live, but with a possible maximum known wingspan of about 7 m (Martill & Unwin 2011) they were certainly big enough (for comparison, an Australian pelican has a wingspan of about 2.5 metres). Ornithocheirids have been recorded from numerous parts of the world—Europe, South America, Africa and China—and, like the large seabirds that are perhaps their closest modern analogues (where 'closest' is a relative term), were probably found worldwide.

Reconstruction of Ornithocheirus mesembrinus, by Dmitry Bogdanov.

The 'misunderstood' in the title to this post refers specifically to the type genus, Ornithocheirus, which has suffered something of an identity crisis over the years. In the 1800s, 'Ornithocheirus' was used as a catch-all genus for almost all Cretaceous European pterosaurs, many known from only fragmentary remains. Eventually, the name came to be associated with a number of species centred around the British O. compressirostris. However, Unwin (2001) pointed out that, at its earliest publication, only one valid species was associated with Ornithocheirus, O. simus, and that species automatically becomes the type of the genus. Ornithocheirus simus is not currently regarded as congeneric with 'O.' compressirostris (and had for many years been treated under the name of Criorhynchus, e.g. Wellnhofer 1991), and so most species previously treated as Ornithocheirus are now treated as a genus Lonchodectes, and not ornithocheirids. Just to confuse matters further, however, some recent authors have continued to treat Ornithocheirus as typified by O. compressirostris, and refer to the 'Ornithocheiridae' of Unwin (2001) as the 'Anhangueridae'. On the other hand, some recent phylogenies have even suggested that Lonchodectes may itself be related to the Ornithocheiridae (e.g. Andres & Ji 2008).

Reconstruction of Coloborhynchus piscator, by Joseph Conway.

Ornithocheirus simus was originally described from a piece of the front of the rostrum found in the Cambridge Greensand of England. This piece was notably deep, and so O. simus was reconstructed as having a short, deep puffin-like skull. It wasn't until the later discovery of a more complete skull in a closely-related South American species, Ornithocheirus mesembrinus (alternatively known as Tropeognathus mesembrinus), that a more accurate reconstruction was possible: Ornithocheirus species had a long rostrum, similar to that found in related pterosaurs, but with prominent rounded dorsal and ventral crests at the distal end. Species of another ornithocheirid genus, Anhanguera (also known from England and South America), had rostral crests set further back and differently shaped. These crests most likely served some form of display function; suggestions that they may have aided in the capture of fish on the wing by easing the rostrum's passage through the water (Wellnhofer 1991) seem unlikely, as other ornithocheirid genera, such as Brasileodactylus and Barbosania, lacked rostral crests entirely (Elgin & Frey 2011). The possibility has been raised that some crested and crestless forms may represent different sexes of the same species, but unfortunately the fossil record of ornithocheirids may not be extensive enough to establish whether this is the case.

The skull of Ludodactylus piscator, via Darren Naish.

The phylogeny of pterosaurs remains a contentious issue but most studies have agreed that ornithocheirids form part of a clade that also includes the Istiodactylidae, Pteranodontidae and Nyctosaurus (though how exactly these taxa are interrelated has not been agreed upon). Ornithocheirids are distinguished from related forms by the arrangement of their teeth, with the first three pairs enlarged to form a terminal rosette. Most ornithocheirids are also distinguished from Pteranodontidae and Nyctosaurus by the absence of a crest on the back of the head. A noteworthy exception is Ludodactylus sibbicki, described by Frey et al. (2003) from a skull possessing a crest at least basally like that of Pteranodon (the skull is preserved on a slab of rock prepared commercially, and the distal portion of the crest [if it had been present] was removed when the slab was cut). However, it is worth noting that Ludodactylus has not (to my knowledge) been included in a formal phylogenetic analysis. Ludodactylus was identified as an ornithocheirid due to its tooth morphology, but the absence of teeth in Pteranodontidae and Nyctosaurus makes them incomparable in this regard. As the Istiodactylidae (with their broad, duck-like rostra) are also reasonably autapomorphic in their skull morphology, I can't help wondering whether the supposed ornithocheirid characters might be plesiomorphic for the larger pteranodontoid clade. But that, of course, is pure speculation on my part, and something only further study could establish.

REFERENCES

Andres, B., & Ji Q. 2008. A new pterosaur from the Liaoning Province of China, the phylogeny of the Pterodactyloidea, and convergence in their cervical vertebrae. Palaeontology 51 (2): 453-469.

Elgin, R. A., & E. Frey. 2011. A new ornithocheirid, Barbosania gracilirostris gen. et sp. nov. (Pterosauria, Pterodactyloidea) from the Santana Formation (Cretaceous) of NE Brazil. Swiss Journal of Palaeontology 130: 259-275.

Frey, E., D. M. Martill & M.-C. Buchy. 2003. A new crested ornithocheirid from the Lower Cretaceous of northeastern Brazil and the unusual death of an unusual pterosaur. In Evolution and Palaeobiology of Pterosaurs (E. Buffetaut & J.-M. Mazin, eds) Geological Society Special Publications 217: 55-63. The Geological Society: London.

Martill, D. M., & D. M. Unwin. 2011. The world’s largest toothed pterosaur, NHMUK R481, an incomplete rostrum of Coloborhynchus capito (Seeley, 1870) from the Cambridge Greensand of England. Cretaceous Research 34: 1-9.

Unwin, D. M. 2001. An overview of the pterosaur assemblage from the Cambridge Greensand (Cretaceous) of Eastern England. Mitt. Mus. Nat.kd. Berl., Geowiss. Reihe 4: 189-221.

Wellnhofer, P. 1991. The Illustrated Encyclopedia of Pterosaurs. Salamander Books: London (reprinted 2000, in The Illustrated Encyclopedia of Dinosaurs (D. Norman & P. Wellnhofer). Salamander Books).

Southern Snakes at Sea

Bandy-bandy, Vermicella annulata, either engaged in an alarm display or participating in a game of croquet. Photo from here.

The front-fanged snakes are a distinctive clade distinguished, as it says on the label, by their well-developed venom-injecting fangs at the front of the mouth. For a long time, the front-fanged snakes were treated as two families, the terrestrial Elapidae and the sea snakes of the Hydrophiidae. However, it has become well-established that the sea snakes are derived from within the Elapidae, and 'Hydrophiidae' became the elapid subfamily Hydrophiinae. As well as its original quota of sea snakes, the Hydrophiinae also now includes the Australo-Papuan species of terrestrial Elapidae. The sea snakes, as it turns out, are not monophyletic within the Hydrophiinae: the sea kraits of the genus Laticauda form the sister group to other hydrophiines, while the remaining sea snakes form a deeply-nested clade (the Hydrophiini) within the terrestrial hydrophiines (Sanders et al. 2008).


Yellow-lipped sea krait Laticauda colubrina, from here.

Sea kraits differ from hydrophiin sea snakes in that they still spend part of their lives on land. They hunt and feed aquatically, mostly on eels, with females catching larger, deeper-living prey than males and juveniles (Shine & Shetty 2001). However, after feeding they tend to return to land to digest their prey. Sea kraits also mate and lay their eggs on land. One possible exception has been claimed for the Rennell Island sea krait Laticauda crockeri which, being restricted to an brackish inland lake on Rennell Island in the Solomons, is also one of the few freshwater sea kraits. Laticauda crockeri has never been recorded on land, and the local people claim that it produces live young, reporting that young can be found within females. In contrast, a sympatric population of the more widespread yellow-lipped sea krait L. colubrina is correctly reported by Rennell Islanders as a terrestrial egg-layer. Unfortunately, Cogger et al. (1987) failed to collect gravid females in their study of L. crockeri and were unable to confirm the local reports.


Yellow-bellied sea snake Pelamis platurus photographed off Costa Rica by Zoltan Takacs.

Hydrophiins, in contrast, are truly marine, bearing live young and unable to move on land. Both sea kraits and hydrophiins have deep paddle-shaped tails, but the tail of hydrophiins differs from that of sea kraits in being supported by extensions of the vertebral apophyses. Sea snakes are widely recognised as among the most venomous of living snakes, but are also known as mostly unlikely to bite humans (different species, of course, exhibit different levels of agression); sea snakes do not even necessarily inject venom when they do bite (Senanayake et al. 2005). Two notable exceptions to the high venom strength of most sea snakes are the marbled sea snake Aipysurus eydouxii and the turtle-head sea snake Emydocephalus annulatus, both specialist feeders on fish eggs. Fish eggs, of course, do not tend to put up much of a fight, and the venom strength of these species is less than one-fiftieth that of other sea snakes (Li et al. 2005). They also have reduced fangs and poison glands, but on the other hand they do have stronger throat muscles (improving their suction).


Western brown snake Pseudonaja mengdeni, photographed by Dan Lynch.

Among the terrestrial hydrophiines, the Hydrophiini are most closely related to a clade of viviparous species including, among others, the tiger snakes Notechis and the Australian copperheads Austrelaps (Sanders et al. 2008). The origin of viviparity in Hydrophiinae remains unsettled. Scanlon & Lee (2004) found support, albeit low, for a single viviparous clade, but Sanders et al. (2008) found three independent viviparous clades—the large-bodied viviparous clade just mentioned, a second clade of smaller snakes such as the ornamental snakes Denisonia and the hooded snakes Suta, and the death adders Acanthophis as a third clade—but were unable to significantly reject monophyly. Similarly, Scanlon & Lee (2004) posited a single origin for burrowing hydrophiines such as the Vermicella pictured at the top of this post (a specialised predator of Typhlopidae blind snakes), but Sanders et al. (2008) supported two separate clades with Vermicella distant from other burrowing taxa. One thing they did agree on was a close relationship between the brown snakes Pseudonaja and the taipans Oxyuranus.

Offhand, in case anyone was hoping that a post on elapids might lead me to a discussion of the... ahem... works of one Raymond Hoser: at one point, I would indeed have happily delved into the subject. But I have to confess that, as time marches on, I find myself increasingly sympathetic to C. T. Simpson's dismissal of the Nouvelle École: "Life is too short and valuable to be wasted in any attempt at deciphering such nonsense".

REFERENCES

Cogger, H., H. Heatwole, Y. Ishikawa, M. McCoy, N. Tamiya & T. Teruuchi. 1987. The status and natural history of the Rennell Island sea krait, Laticauda crockeri (Serpentes: Laticaudidae). Journal of Herpetology 21 (4): 255-266.

Li, M., B. G. Fry & R. M. Kini. 2005. Eggs-only diet: its implications for the toxin profile changes and ecology of the marbled sea snake (Aipysurus eydouxii). Journal of Molecular Evolution 60: 81-89.

Sanders, K. L., M. S. Y. Lee, R. Leys, R. Foster & J. S. Keogh. 2008. Molecular phylogeny and divergence dates for Australasian elapids and sea snakes (Hydrophiinae): evidence from seven genes for rapid evolutionary radiations. Journal of Evolutionary Biology 21 (3): 682-695.

Scanlon, J. D., & M. S. Y. Lee. 2004. Phylogeny of Australasian venomous snakes (Colubroidea, Elapidae, Hydrophiinae) based on phenotypic and molecular evidence. Zoologica Scripta 33 (4): 335-366.

Senanayake, M. P., C. A. Ariaratnam, S. Abeywickrema & A. Belligaswatte. 2005. Two Sri Lankan cases of identified sea snake bites, without envenoming. Toxicon 45 (7): 861-863.

Shine, R., & S. Shetty. 2001. Moving in two worlds: aquatic and terrestrial locomotion in sea snakes (Laticauda colubrina, Laticaudidae). Journal of Evolutionary Biology 14: 338-346.

Small lizards of South America

Three readers made comments about the apparent identity of yesterday's ID challenge; none of them, I'm afraid, even came close.


The gymnophthalmid lizard Leposoma hexalepis, photographed in Venezuela by Carl Franklin.

Gymnophthalmids are a family of nearly 200 species (new ones continue to be described at a steady rate) of small (4-15 cm excluding the tail) insectivorous lizards from South America. So little regarded is this family that no really good vernacular name exists for it and its members are generally referred to by what they are not: they are referred to as 'microteiids' in contrast to the related but physically larger family Teiidae. Today's Taxon of the Week is a clade within the Gymnophthalmidae known as the Ecpleopini or Ecpleopinae*, depending on whom you ask.

*Technically, that should be 'Ecpleopodini', but all recent publications have used the 'incorrect' spelling (so far I've only seen one publication from 1887 use the correct spelling). The online page for one recent article includes a footnote mentioning the correct spelling but the note does not appear to be present in the printed article.

The Ecpleopini include (at present) about thirty species, about half of which are placed in the genus Leposoma. The clade is currently supported by molecular analyses without any identified morphological synapomorphies (Pellegrino et al., 2001; Rodrigues et al., 2005). Different analyses recover different relationships between the constituent genera except for a small clade of the genera Colobosauroides, Dryadosaura and Anotosaura (Rodrigues et al., 2005). This clade represents one of a number of lineages within Gymnophthalmidae to develop an elongate body form and reduced limbs together with a fossorial lifestyle. Anotosaura has also lost its external ear openings.


Another ecpleopin, Arthrosaura reticulata, photographed in Peru by Thomas Stromberg.

The species of the genus Leposoma are more generalised in their overall appearance but still not without their intrigues. Leposoma species can be divided between two groups distinguished by their chromosome number and arrangement. The L. scincoides group possess 52 chromosomes of a range of sizes while species of the L. parietale group ancestrally possess 44 chromosomes with a clear size distinction between 20 major and 24 minor chromosomes. The only exception to this pattern is L. percarinatum, a parthenogenetic species* from Mato Grosso in Brazil with 66 chromosomes: one of the few known examples of a triploid genome in vertebrates. When the triploid nature of L. percarinatum was identified, it was suggested that it might be derived from a hybridisation event between two diploid parents. Since then, a diploid form of L. percarinatum has also been identified that may represent one of the parents of the triploid form; perhaps the other is the sympatric bisexual** diploid L. ferreirai (Laguna et al., 2010). Which does still leave the question of how the usual parthenogenesis of the diploid L. percarinatum came to be in the first place.

*Or, as it seems to be called, a 'parthenoform' (presumably to avoid having to refer to a parthenogenetic taxon as a 'species').

**In the sense of possessing two sexes, not the other sense.

REFERENCES

Laguna, M. M., M. T. Rodrigues, R. M. L. dos Santos, Y. Yonenaga-Yassuda, T. C. S. Ávila-Pires, M. S. Hoogmoed & K. C. M. Pellegrino. 2010. Karyotypes of a cryptic diploid form of the unisexual Leposoma percarinatum (Squamata, Gymnophthalmidae) and the bisexual Leposoma ferreirai from the lower Rio Negro, Amazonian Brazil. Journal of Herpetology 44 (1): 153-157.

Pellegrino, K. C. M., M. T. Rodrigues, Y. Yonenaga-Yassuda & J. W. Sites Jr. 2001. A molecular perspective on the evolution of microteiid lizards (Squamata, Gymnophthalmidae), and a new classification for the family. Biological Journal of the Linnean Society 74: 315-338.

Rodrigues, M. T., E. M. X. Freire, K. C. M. Pellegrino & J. W. Sites Jr. 2005. Phylogenetic relationships of a new genus and species of microteiid lizard from the Atlantic forest of north-eastern Brazil (Squamata, Gymnophthalmidae). Zoological Journal of the Linnean Society 144 (4): 543-557.

A Question of Availability

About a year ago, I wrote a post discussing the potential difficulty of establishing whether a taxonomic work of restricted availability has been validly 'published'. If you head over to Mickey Mortimer's Theropod Database Blog, you'll be presented with a perfect (and perfecty 'orrible) example of just this issue, concerning the dinosaurological publications of one Stephan Pickering. Mickey has regarded the works as not validly published; Pickering himself has posted a number of comments to argue otherwise.

The arguments that have been made there about copyright (a completely separate issue from ICZN availability), private publication and peer review (in which the ICZN effectively has no interest) are irrelevant to the question of whether the works count as published for ICZN purposes. The important details in that regard are:

1. Pickering had 50 copies of each of the works professionally printed in 1995 (at least one was printed later in 1999). I have not personally seen the works in question, but the indications are that the diagnoses presented therein would satisfy ICZN requirements.

2. No printed copies of the works were deposited in institution libraries (and Pickering has objected strenuously to suggestions that he should have done so); however, copies were distributed to various recipients. At least some copies were distributed shortly after printing.

3. An excerpt or reprint of one of the works was distributed as an insert in 1996 with an issue of the popular magazine _Prehistoric Times_.

As a reminder, the ICZN requirements for a work to count as 'published' are:

8.1. Criteria to be met. A work must satisfy the following criteria:

8.1.1. it must be issued for the purpose of providing a public and permanent scientific record,

8.1.2. it must be obtainable, when first issued, free of charge or by purchase, and

8.1.3. it must have been produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies.

Do Pickering's works meet those requirements? 50 copies is low for a publication run but I don't think it can be argued to fail the requirements of 8.1.3. Publications existing in similar or lower numbers have been accepted as valid in the past. Similarly, the fact that Pickering distributed copies to various recipients suggests at least a nominal accordance with 8.1.2 (that most of these recipients, such as Michael Crichton and Stephen Spielberg, appear to have not been working palaeontologists is problematic but does not violate any explicit ICZN requirement). However, I think that a strong argument can be made that by refusing to place any copies in public depositories, Pickering has failed to meet the requirements of 8.1.1, a "public and permanent scientific record", whatever his original intentions may have been ("by their fruits you shall know them", to insert a touch of pretension). To provide a permanent scientific record, it is necessary that future researchers be able to evaluate the publication; if they are unable to gain access to a copy then they are unable to evaluate it. Unless any of the recipients of Pickering's publications take it upon themselves to secure the future availability of the works, they will end up being lost to history. As already noted by Mickey, the _Prehistoric Times_ insert, having had a much wider distribution, is a potential exception to this problem; my personal inclination would be to accept the names diagnosed therein as available though again the future availability of the work is a pending question.

Indeed, hovering over all of this is a much broader question about the publication requirements of the ICZN. Implicit in the current rules is the assumption that "once available, always available" but time, of course, is a great destroyer. In my earlier post, I discussed the rare Japanese journal Lansania, for some issues of which only a handful of (or even single) copies survive while others may have been lost entirely. There can be no doubt that the publisher of Lansania, Kyukichi Kishida, intended these issues to provide a "public and permanent scientific record"; they have evidently failed to meet that intention. What becomes of taxa whose original descriptions can no longer be evaluated?