Canadian toad
Canadian toad | |
---|---|
Canadian toad at Wagner Natural Area, Alberta | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Bufonidae |
Genus: | Anaxyrus |
Species: | A. hemiophrys
|
Binomial name | |
Anaxyrus hemiophrys (Cope, 1886)
| |
Canadian toad range | |
Synonyms | |
Bufo hemiophrys Cope, 1886 |
The Canadian toad (Anaxyrus hemiophrys), also known
Description
The Canadian toad can grow to around 7.6 cm (3 in) in length. Fully grown adult males are usually 5.6 to 6.9 cm (2.2–2.7 in), while females are a little bigger between the ranges of 5.6 and 7.9 cm (2.2–3.1 in)
The coronal crests of Anaxyrus hemiophrys are well defined. The interorbital crests are narrow, relatively sharp-edged, non-porous and are widely separated. They run relatively parallel throughout most of their length, as far posterior as the level of the coronal crests. Posterior to that level they flare laterally to join the postorbital crests, delimiting the anterolateral edge of the postcoronal plane. Postcoronal plane is clearly defined and sloped posteroventrally. It is smooth and subtriangular, its apex directed posteriorly and it ends at the foramen magnum. Its sides are delimited anteriorly by short parietal crests. Particularly useful externally is the interorbital crest shape. In Anaxyrus hemiophrys the posterior ends of the crests almost invariably diverge at least slightly where they join the postorbital crests (usually not evident externally).
On the back of the external face of the tibia are several rows of dermal tubercles. The heel of the hind foot when the hind leg is extended comes level to the posterior edge of the orbit. The tubercles of the metatarsals are large. The internal one is very wide and prominent with an extensive acute edge and the external one is smaller with a free cutting edge that is transverse to the length of the tarsus.[14]
Taxonomy and systematics
Anaxyrus hemiophrys was first described in 1886 by Edward Drinker Cope in the Proceedings of the American Philosophical Society as Bufo hemiophrys. Cope describes the anatomical characteristics and superficial characteristics, comparing them with other related species. Cope determined that the Anaxyrus hemiophrys differs from most of the other North American "Bufo" species because of the lack of postorbital crests and in having spots on its belly.
The closely related Anaxyrus baxteri (the Wyoming toad) was once considered a subspecies of the Anaxyrus hemiophrys. It is a relict population that is believed to be a remnant from when the Anaxyrus hemiophrys, or its ancestors, range was larger.[15]
The range of territory covered by Anaxyrus hemiophrys is fairly large although it has been shown to be declining in southern regions of Alberta.[16] In Canada Anaxyrus hemiophrys' range extends from a small southern patch in the Northwest Territories down through eastern and central Alberta. It spreads east from there through most of Saskatchewan and into southwestern Manitoba. In the United States its range goes from northern Montana and heads east into North Dakota. Once in North Dakota it dips south into the northeastern corner of South Dakota and also enters northwestern Minnesota.
Ecology
Diet
The
Reproduction
Breeding for Anaxyrus hemiophrys typically commences during early emergence in late April to early May and goes until August or September. It takes place in aquatic environments. The male grasps the female in a process called
Life cycle
Anaxyrus hemiophrys lays eggs in strings of 6000 eggs and can lay up to 20,000 eggs each year.
Torpor
The process of torpor (hibernation) proceeds as early as late August. The toads burrow in the earth and create little holes to sleep in. These create small mounds known as mima mounds. Each mima mound may contain hundreds of toads.[23] They stay there for the duration of the fall and winter, burrowing deeper as the soil temperature drops.[24] Individual toads usually pick the same spot for torpor each year. Emergence begins once the soil thaws and the toads can dig their way out.[25]
Notes
- . Retrieved 13 November 2021.
- ^ Green (1983)
- ^ Frost (2014)
- ^ Cogger & Zweifel (1998)
- ^ Lannoo (2005)
- ^ Taylor, Williams & Mills (1999)
- ^ Cope (1886)
- ^ Cope (1886)
- ^ Wittliff (1962)
- ^ "Search - the Encyclopedia of Earth".
- ^ Smith et al. (1998)
- ^ Green (1983)
- ^ Smith et al. (1998)
- ^ Cope (1886)
- ^ Lanoo (2005)
- ^ Hamilton et al. (1980)
- ^ Lannoo (2005)
- ^ Moore & Strickland (1954)
- ^ Lannoo (2005)
- ^ "Canadian Toad: Nature Snapshots from Minnesota DNR: Minnesota DNR". Archived from the original on 2010-04-21. Retrieved 2010-03-19.
- ^ "Bufo hemiophrys – Canadian toad – Northern Rockies Natural History Guide". Archived from the original on 2010-06-21. Retrieved 2010-03-18.
- ^ Eaton et al. (2005)
- ^ "Canadian Toad: Nature Snapshots from Minnesota DNR: Minnesota DNR". Archived from the original on 2010-04-21. Retrieved 2010-03-19.
- ^ Feder & Burggren (1993)
- ^ Lannoo (2005)
References
- Pauly, Gregory B.; Hillis, David M.; Cannatella, David C. (2004). "The History of a Nearctic Colonization: Molecular Phylogenetics and Biogeography of the Nearctic Toads (Bufo)". Evolution. 58 (11): 2517–2535. S2CID 10281132.
- Frost, Darrel R. (2014). "Anaxyrus hemiophrys (Cope, 1886)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 11 February 2014.
- IUCN SSC Amphibian Specialist Group (2015). "Anaxyrus hemiophrys". . Retrieved 13 November 2021.
- Green, David M. (1983). "Allozyme Variation through a Clinal Hybrid Zone between the Toads Bufo americanus and B. hemiophrys in Southeastern Manitoba". Herpetologica. 39 (1): 28–40. JSTOR 3892473.
- Moore, J. E.; Strickland, E. H. (1954). "Notes on the Food of Three Species of Alberta Amphibians". The American Midland Naturalist. 52 (1): 221–224. JSTOR 2422059.
- Cogger, H. G., & Zweifel, R.G. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press., 1998
- Lannoo, M. J. Amphibian Declines: The Conservation Status of United States Species, University of California Press, 2005
- Cope, E. D. (1886). "Synonymic List of the North American Species of Bufo and Rana, with Descriptions of Some New Species of Batrachia, from Specimens in the National Museum". Proceedings of the American Philosophical Society. 23 (124): 514–526. JSTOR 983330.
- Smith, Hobart M.; Chiszar, David; Collins, Joseph T.; Van Breukelen, Frank (21 January 1998). "The taxonomic status of the Wyoming toad, Bufo baxteri Porter". Contemporary Herpetology: 1–5. .
- Taylor, Sharon K.; Williams, Elizabeth S.; Mills, Kenneth W. (January 1999). "Mortality of Captive Canadian Toads from Basidiobolus ranarum Mycotic Dermatitis". Journal of Wildlife Diseases. 35 (1): 64–69. S2CID 20337806.
- Feder, Martin E.; Burggren, Warren W. (1992). Environmental Physiology of the Amphibians. University of Chicago Press. ISBN 978-0-226-23944-6.
- Eaton, Brian R; Paszkowski, Cynthia A; Kristensen, Kent; Hiltz, Michelle (1 November 2005). "Life-history variation among populations of Canadian Toads in Alberta, Canada". Canadian Journal of Zoology. 83 (11): 1421–1430. doi:10.1139/z05-138.
- Hamilton, I.A., Skilnick, J.L., Troughton, H., Russell, A.P. & Powell, G.L. (1998). Status of the Canadian toad (Bufo hemiophrys) in Alberta. Alberta Wildlife Status Report No. 12, Alberta Environmental Protection, Wildlife Management Division, and the Alberta Conservation Association, Edmonton, AB.
- Wittliff, James L. (1962). "Parotoid Gland Secretions in Two Species Groups of Toads (Genus Bufo)". Evolution. 16 (2): 143–153. JSTOR 2406193.