Pygopodidae

Pygopodidae, commonly known as legless lizards, snake-lizards, or flap-footed lizards, is a family of squamates with reduced or absent limbs, and are a type of gecko.[2] There are at least 35 species in two subfamilies and eight genera. They have unusually long, slender bodies, giving them a strong resemblance to snakes. Like snakes and most geckos, they have no eyelids, but unlike snakes, they have external ear holes and flat, unforked tongues.[3] They are native to Australia and New Guinea.[4]

Pygopodidae
Pygopus lepidopodus, from Brehms Tierleben, 1892.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Superfamily:	Pygopodoidea
Family:	Pygopodidae Boulenger, 1884[1]
Subfamilies
2, See text
Geographic range of the family Pygopodidae in Australia and New Guinea.

Pygopodids have no fore limbs at all, but they do possess vestigial hind limbs in the form of small, flattened flaps.[3] These may have some role in courtship and defensive behaviour, and may even aid in locomotion through vegetation. Some species are insectivorous burrowing animals, but others are adapted to moving through dense spinifex or other vegetation. Like the geckos, pygopodids lay two eggs in each clutch[3] and nest communally. Some nests have been found to have as many as 30 eggs. Also like other geckos, pygopodids have the ability to vocalise - emitting a high-pitched squeak. Snakes are incapable of vocalising.

Pygopodids can hear tones higher than any other reptiles. Individuals in the species Delma pax can respond to a 60-decibel sound with a frequency of 11,100 Hz, more than an octave above the highest note on a standard piano.[5]

Taxonomy

Pygopodidae is one of several taxonomic families of Geckos, and is most closely related to other Australian gecko families Carphodactylidae and Diplodactylidae.[6][7][4] The pygopodids and other geckos share a number of characteristics; pygopodids may actually be considered as limbless geckos.[7] Shared characteristics include: the production of parchment-shelled eggs in clutch sizes of two;[6][7] the ability to lick clean the clear spectacles which cover their lidless eyes;[8] and the sharing of a voice in the form of a “harsh squeak”.[7] The skulls and inner ears of the pygopodids are also similar to those of geckos.[4]

Classification

FAMILY PYGOPODIDAE

• Subfamily Lialisinae
  • Tribe Lialisini
    • Genus Lialis (two species)
• Subfamily Pygopodinae
  • Genus Delma (21 species)
  • Genus Paradelma (monotypic)
  • Genus Pygopus (five species)
  • Tribe Aprasiaini
    • Subtribe Aprasiaina
      • Genus Ophidiocephalus (monotypic)
      • Genus Aprasia (13 species)
    • Subtribe Pletholaxina
      • Genus Pletholax (2 species)

Differentiating from snakes

Legless lizards are often killed due to their similar appearance to snakes.[7] A number of external characteristics can be used to distinguish legless lizards (including the hooded scaly-foot) from snakes:[9][7][8]

• Flap-footed lizards have vestigial hindlimbs
• Legless lizards have broad, fleshy tongues, dissimilar from the forked tongues of snakes
• Most legless lizards have external ears
• Ventral scales are in a paired series
• Unbroken tails in legless lizards are much longer than the body, whereas snake bodies are longer than their tails.

See also

Lialis burtonis

• Limbless vertebrates

References

1. "Pygopodidae". Dahms Tierleben. www.dahmstierleben.de/systematik/Reptilien/Squamata/Gekkota/Pygopodidae.
2. Gamble, Tony; Greenbaum, Eli; Jackman, Todd R.; Russell, Anthony P.; Bauer, Aaron M. (June 27, 2012). "Repeated origin and loss of adhesive toepads in geckos". PLOS ONE. 7 (6): e39429. Bibcode:2012PLoSO...739429G. doi:10.1371/journal.pone.0039429. PMC 3384654. PMID 22761794.
3. Bauer, Aaron M. (1998). Cogger HG, Zweifel RG (eds.). Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 150–152. ISBN 0-12-178560-2.
4. Shea, Glenn. "Fauna of Australia: Family Pygopodidae" (PDF). Archived from the original (PDF) on 24 August 2012. Retrieved 16 June 2012.
5. Manley GA, Kraus JEM (2010). "Exceptional high-frequency hearing and matched vocalizations in Australian pygopod geckos" (PDF). The Journal of Experimental Biology. 213 (11): 1876–1885. doi:10.1242/jeb.040196. PMID 20472775. S2CID 17996056.
6. Patchell, Frederick; Richard Shine (February 1986). "Food habits and reproductive biology of the Australian legless lizards (Pygopodidae)". Copeia. 1986 (1): 30–39. doi:10.2307/1444884. JSTOR 1444884.
7. Wilson, Steve (2003). A Complete Guide to Reptiles of Australia. New Holland: Reed.
8. Wilson, Steve (2005). A Field Guide to Reptiles of Queensland. Australia: New Holland.
9. Hoser, Raymond (1989). Australian Reptiles and Frogs. Pierson & Co.

Further reading

• Boulenger GA. (1884). Synopsis of the Families of existing Lacertilia. Ann. Mag. Nat. Hist., Fifth Series 14: 117-122. (Pygopodidae, new family, p. 119).
• Goin CJ, Goin OB, Zug GR. (1978). Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman. xi + 378 pp. ISBN 0-7167-0020-4. (Family Pygopodidae, pp. 285–286).
• Kluge AG. (1974). A taxonomic revision of the lizard family Pygopodidae. Miscellaneous Publications, Museum of Zoology, University of Michigan (147): 1-221.