Couch's Spadefoot (Scaphiopus couchii)
Description: Scaphiopus couchii has a stout body and is 2.25 to 3.5 inches. The color varies from bright green-yellow to brown-yellow. The dorsal surface is mottled with dark green, brown, or black markings, and the dark markings are more extensive in females. The ventral surface is white. The skin is covered with many small warts. The hind limbs have a single, sickle-shaped tubercle, or spade on the inner surface. The pupils are vertical in bright light.
Habitat: Scaphiopus couchii lives underground in burrows in grassland prairies and mequite savannas. They dig these burrows in soft earth by backing into the ground and digging with hind feet, which are armed with spades. They rock the body as they dig; dirt falls into the burrows on top of the toads. Scaphiopus couchii seeks shelter under fallen logs and is adapted to arid and semi-arid conditions.
Range: Couch's spadefoot toad is native to the United States southwest of southeastern Colorado and central Oklahoma, northern Mexico and the Baja peninsula. They can be found throughout the Sonoran Desert, which includes parts of southern Arizona and California.
Diet: Unlike most tadpoles, which are exclusively herbivores and filter feeders, spadefoot tadpoles are omnivores. They also eat dead insects and tadpoles, as well as fairy shrimp.
Reproduction: Water is a necessary medium for the fertilization of spadefoot eggs, and once the eggs hatch, water also provides a place for tadpoles to mature to the adult stage. Because of the importance of water, spadefoots are active during the wet season spring and summer in the Northern Hemisphere), and remain underground during the dry season (fall and winter). When a summer thunderstorm arrives, the male toads emerge from underground and look for pools of rainwater. When they find water, the males produce a mating call that attracts female toads. New research has shown that females tend to be more attracted to bright-colored males over their dark-colored peers. Thus creating a new aspect in their determination of the male's size and condition. Because the pools of water may be short-lived, mating occurs the first night after rainfall begins.
During reproduction, the male mounts the female and releases sperm to fertilize the eggs, which are deposited in the pools of water in the form of a floating mass. The eggs hatch into tadpoles, which quickly mature into adults. They must reach this stage before the pool of water evaporates, and thus they sometimes mature in as little as 9 days after the eggs are laid. Western spadefoot toads take longer to mature (at least three weeks).
The small pools of water are warmed by the sun, which speeds up the growth of the tadpoles. Tadpoles will eat a variety of foods, such as small insects near the pool and algae, which they scrape off rocks. They also filter microorganisms from the water as it is passed over their gills. Tadpoles gather in wriggling masses, stir up the muck on the bottom of the pool, and filter out the organic nutrients.
Status: Because of the life cycles of Scaphiopus couchii (both aquatic and terrestrial stages), the thin, permeable skin and the underground dwelling, this species is especially sensitive to environmental perturbations. Such environmental problems may include acid rain, increasing ultraviolet irradiation, changes in land and water, and other factors. As always, humans must begin taking greater resonsibility for the world around them.
»» Kingdom: Animalia - Animals
»» Phylum: Chordata - Chordates
»» Subphylum: Vertebrata - Vertebrates
»» Class: Amphibia - Amphibians
»» Order: Anura - Frogs & Toads
»» Family: Scaphiopodidae - American Spadefoot Toads
»» Genus: Scaphiopus
»» Species: Scaphiopus couchii - Couch's Spadefoot
This article uses material from the Wikipedia article "Couch's Spadefoot Toad", which is released under the Creative Commons Attribution-Share-Alike License 3.0. Content may have been omitted from the original, but no content has been changed or extended.
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