Pygmy short-horned lizard

The pygmy short-horned lizard (Phrynosoma douglasii) is a species of small horned lizard that occurs in the northwestern United States as well as in the southwestern Canada. Like other horned lizards, it is often called a "horned toad" or "horny toad," but it is not a toad at all. It is a reptile, not an amphibian.[3]

Pygmy short-horned lizard
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Phrynosomatidae
Genus: Phrynosoma
Species:
P. douglasii
Binomial name
Phrynosoma douglasii
(Bell, 1828)[2]

Etymology

The specific name, douglasii, is in honor of Scottish botanist David Douglas.[4]

Identification

The pygmy short-horned lizard is often mistaken for its close relative the greater short-horned lizard (P. hernandesi ) which has the same basic body type consisting of small pointed scales around the head and back.[3] Until recent mitochondrial DNA evidence, the greater short-horned was considered to be the same species as the pygmy short-horned. They are now considered distinct species with the pygmy short-horned lizard occupying the northwest portion of the United States and extreme southern British Columbia (now extirpated from Canada).[3] When placed together the two are easily distinguished at full size, the pygmy short-horned lizard being much smaller. The greater short-horned lizard is a highly variable species with different geographic populations exhibiting differences in colour, pattern, and size, with some authorities describing five subspecies. The pygmy short-horned lizard ranges in size from 1.25–2.5 in (3.2–6.4 cm) in snout-to-vent length (SVL) and is a flat-bodied, squat lizard with short spines crowning the head.[5] They have a snub-nosed profile and short legs. The trunk is fringed by one row of pointed scales, while the belly scales are smooth. The colour is gray, yellowish, or reddish-brown, and there are two rows of large dark spots on the back. When threatened or aggressive, their colours become more intense.The pygmy short-horned lizard is also a species at risk in Alberta according to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

Behavior and Ecology

Diet varies from different habitats, but mostly among age and sex classes; neonates feed among almost exclusively on ants (89%) while adults consume fewer ants (72%) and yearlings consume the lowest proportion of ants (60%). [6]

References
  1. Hammerson, G.A. (2007). Phrynosoma douglasii. The IUCN Red List of Threatened Species doi:10.2305/IUCN.UK.2007.RLTS.T64075A12741891.en
  2. The Reptile Database. .
  3. Sherbrooke, Wade C. 2003. Introduction to Horned Lizards of North America. California Natural History Guides. Oakland, California: University of California Press. 191 pp. ISBN 978-0520228276.
  4. Beolens, Bo; Watkins, Michael; Grayson, Michael. (2011). "Phrynosoma douglasi", p. 75 The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. ISBN 978-1-4214-0135-5.
  5. Stebbins, Robert C. (2003). "Phrynosoma douglasii", pp. 303–304 + Plate 34 + Map 101 in A Field Guide to Western Reptiles and Amphibians: Third Edition. The Peterson Field Guide Series. Boston and New York: Houghton Mifflin Company. ISBN 978-0-395-98272-3.
  6. Lahti, Megan; Beck, Daniel (April 2008). "Ecology and ontogenetic variation of diet in the pigmy short-horned lizard (Phrynosoma douglasii)". American Midland Naturalist. 159 (2): 327–339. doi:10.1674/0003-0031(2008)159[327:EAOVOD]2.0.CO;2.

Further reading
  • Bell, Thomas. 1828. "Description of a new Species of Agama, brought from the Columbia River by Mr. Douglass [sic]". Trans. Linnean Soc. London 16: 105–107 + Plate X. ("Agama Douglassii [sic]", new species). (in English and Latin).
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