Plains spadefoot toad
| Plains spadefoot toad | |
|---|---|
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Amphibia |
| Order: | Anura |
| Family: | Scaphiopodidae |
| Genus: | Spea |
| Species: | S. bombifrons
|
| Binomial name | |
| Spea bombifrons (Cope, 1863)
| |
| Synonyms | |
The plains spadefoot toad (Spea bombifrons) is a species of American spadefoot toad which ranges from southwestern Canada, throughout the Great Plains of the western United States, and into northern Mexico. Like other species of spadefoot toads, they get their name from a spade-like projections on their hind legs which allow them to dig into sandy soils. Their name, in part, comes from their keratinized metatarsels, which are wide instead of "sickle shaped" . The species name translates as buzzing leaf shaped[1]. This refers to the species distinguishing features; it's buzzing mating call, and it's leaf shaped digging metatarsals. First described by Cope in 1863[2]
Description
The plains spadefoot toad generally grows from 1.5 to 2.5 inches in length, has a round body, with relatively short legs. These toads are usually a tannish to dark brownish color with visible orange spots. They are one of the easiest toads to recognize in their region because of their appearance looking more like a frog. Sometimes, they have light striping on their backs.
As described by USGS 2002 and published on Amphibiweb: "The European, American, or Plains Spadefoot Toad is a small but rotund toad-like frog, generally resembling true toads (Bufonidae) in body form. Spea bombifrons can grow up to 2¼" in snout-vent length. Its skin, which is relatively smooth, can range from gray to brown, sometimes with a greenish hue, and is scattered with darker spots or blotches. The skin is also smoother and thinner than that of Bufonidae. Along the dorsal and lateral surfaces run four vague light stripes, the middle two of which occasionally resemble an hourglass. There are many small tubercles on the otherwise smooth skin. The ventral surface is white and has no markings, although the throat of the male is bluish or grayish on the sides. There is a raised, bony lump (boss) between the large eyes. The eye has an elliptical, vertical, cat-like pupil, and thus differs from the true toads, whose pupils are round. S. bombifrons also differs from Bufo in that it has no parotid glands (or, when present, they are indistinct) (USGS 2002). Like the other members of the family Pelobatidae, or the spadefoots, S. bombifrons is named for its large, well-developed, wedge-shaped, sharp-edged, black tubercle or metatarsal "spade" on the bottom of each hind foot. This bony element, which is capped with a keratinous cover, is used to burrow rear-first ."[3]
Evolutionary/Phylogenic relationships
The origins of Lissamphibia are not finalized. This has a lot to do with the fact that early stem amphibians were a lot more like amniotes in terms of biology. Much of amphibian biology appears to be derived evolution. The earliest known fossil of a burrowing frog is likely Prospea holoserisca[4]
The most basal extant frog species are in the Archeabatrachia suborder. The most primitive frog is arguably Leiopelma[5]
Salienta fossils are the earliest examples of anurans that show a split from Order Caudata. Examples include Triadobatrachus[6] and Czatkobatrachus[7].
Because amphibians might actually be highly derived, this could explain why their fossil record is poor. Multilocus sequence typing has proposed a Late Carboniferous/Early Permian origin around 270 mya.[8]
Geographical distribution and conservation status
This species is found throughout the Midwest from Alberta to Mexico wherever there is suitable soil for a fossorial lifesyle. The species is listed by IUCN 2015 as "least concern" and appears to be expanding it's range, at least northwards into Alberta, Canada.
Behavior
Plains spadefoot toads are nocturnal and secretive. They spend most of the dryer seasons buried in the soil in estivation, typically only emerging during spring and fall rains. Breeding takes place in temporary pools of water left by rainfall, which requires the tadpoles to metamorphose quickly, before the water dries up. Eggs, laid in clutches numbering from 10-250, often hatch within 48 hours of being laid, and the larvae can change into tadpoles in as little as two weeks. The tadpoles exhibit phenotypic plasticity, with some changing from an omnivorous morphology into a cannibalistic carnivorous morph with oversized jaw muscles and pronged beaks. In some cases, female spadefoot toads will choose to mate with Spea multiplicata rather than with males of their own species, if the resulting hybrid tadpole would have higher chances of survival.[9] Character displacement has also been examined in ponds where Spea bombifrons and Spea multiplicata occur together. Reproductive and ecological competition between the two species likely causes selection for smaller and less reproductively successful individuals of Spea multiplicata. [10]
References
- ^ "Frogs and Toads - River Science". www.kansasriverscience.org. Retrieved 2019-11-12.
- ^ "Cope, 1863, Proc. Acad. Nat. Sci. Philadelphia, 15 | Amphibian Species of the World". research.amnh.org. Retrieved 2019-11-27.
{{cite web}}: no-break space character in|title=at position 48 (help) - ^ "AmphibiaWeb - Spea bombifrons". amphibiaweb.org. Retrieved 2019-11-27.
- ^ Chen, C; Bever, S; Yi, Y; Norell., A (2016). "Chen, J., G.S. Bever, H. Yi, and M. A. Norell, 2016. A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia. Scientific Reports. 6, 19209. [X23961] (matrix)". MorphoBank datasets. Retrieved 2019-11-27.
{{cite web}}: line feed character in|title=at position 208 (help) - ^ "Leiopelma", Wikipedia, 2019-10-16, retrieved 2019-11-27
- ^ "Triadobatrachus", Wikipedia, 2019-10-27, retrieved 2019-11-27
- ^ "Czatkobatrachus", Wikipedia, 2019-07-14, retrieved 2019-11-27
- ^ San Mauro, Diego; Vences, Miguel; Alcobendas, Marina; Zardoya, Rafael; Meyer, Axel (2005-05-01). "Initial Diversification of Living Amphibians Predated the Breakup of Pangaea". The American Naturalist. 165 (5): 590–599. doi:10.1086/429523. ISSN 0003-0147.
- ^ Pfennig, Karin S. (2007-11-09). "Facultative Mate Choice Drives Adaptive Hybridization". Science. 318 (5852): 965–967. doi:10.1126/science.1146035. PMID 17991861.
- ^ Pfennig, Karin S; David W Pfennig (October 2005). "Character displacement as the "best of a bad situation": fitness trade-offs resulting from selection to minimize resource and mate competition". Evolution; International Journal of Organic Evolution. 59 (10): 2200–2208. doi:10.1111/j.0014-3820.2005.tb00928.x. ISSN 0014-3820. PMID 16405163.
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