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Fouquette Jr. Historical versus Current Distribution. Burrowing toads Rhinophrynus dorsalis have been a well-known, if infrequently encountered, burrowing anuran of lowland coastal areas in Mesoamerica for some yr Fouquette, , but were not discovered as a component of the U. These toads surface only to breed during heavy rains, perhaps only once per year; thus, they are encountered infrequently by humans.
Few additional reports of this species in Texas have been published since the first one. Burrowing toads have been documented in a limited portion of Starr and Zapata counties in extreme southwestern Texas James, ; Garrett and Barker, ; Dixon, , Across their range, burrowing toads occur from sea level to m, from southern Texas and northern Tamaulipas, Mexico, to Guanacaste Province in Costa Rica.
Duellman and Villa extended the southward range in Honduras and Nicaragua, beyond that indicated by the map of Fouquette , and Foster and McDiarmid noted additional Costa Rican localities. Dixon commented that burrowing toads have not been found in Texas since about ; however, Dixon indicated specimens had been taken in and calls heard in , presumably in the same limited area although no specific literature records were reported.
Historical versus Current Abundance. No basis exists for evaluating any change in abundance over the 35 yr they have been known from the Texas localities.
These animals are ephemerally active in limited arid habitats following heavy rains with flooding. James noted one moderate chorus that was active one night and had no activity on subsequent nights, but a few nights later following another heavy rain , new choruses were found. There are no reports evaluating changes in abundance throughout the rest of their range. Breeding migrations.
Burrowing toads will breed any time of the year after rains create sufficiently deep breeding pools. Males will call from burrows, then emerge to breed in groups that can be large Garrett and Barker, Calling and breeding may occur at the surface of the water or on soil along the flooded sites Fouquette and Rossman, ; James, The distinctive advertisement call has been described by several authors Fouquette and Rossman, ; James, ; Fouquette, , and brief analysis with audiospectrogram was made by Fouquette Individuals occasionally are encountered on roads Fouquette and Rossman, ; James, when there is breeding activity nearby, but there is no information available on dispersal or migratory movements.
Seasonal pools and flooded areas created by heavy rainfall James, ; Garrett and Barker, Egg deposition sites. In ephemeral wetlands, females lay eggs in small clumps that soon separate and float to the water surface Stuart, Length of larval stage. At least 2 mo, likely longer for most animals Stuart, Growth rates, and thus times to metamorphosis, are dependent on food availability Stuart, Larvae were not observed by James in the Texas localities, although she searched for them, and those of other species were abundant.
Tadpoles are phytoplankton feeders and their guts are lined with large caecum-like areas Altig and Kelly, Occasionally, tadpoles may feed on conspecifics Starrett, , although cannibalism was not observed by Stuart Tadpoles school Stuart, ; Foster and McDiarmid, When schooling, tadpoles form massed aggregates of varying sizes Stuart, Schools may be mediated by either lateral line mechanoreceptive cues or olfaction, but apparently not by vision; they also may be influenced by socialization Foster and McDiarmid, Generally, these masses are disc-like, with one estimated to be 25 cm in diameter and 10 cm deep that could have contained thousands of individuals Stuart, Smaller schools may join to form larger schools, larger schools may break up Stuart, Occasionally, larvae in schools will suddenly form a column and swim swiftly towards the surface surfacing behavior; Stuart, Larval polymorphisms.
Unknown and unlikely, although Starrett reported occasional cannibalism.
Menu hit nabigasyon
Juvenile Habitat. No information available, but juveniles presumably burrow in the soil, similar to adults. Adult Habitat.
Friable soils that permit burrowing, including cultivated fields and gardens, are required Garrett and Barker, Duellman pointed out that habitats for this species are typically arid or savanna, tropical or subtropical, non-forested areas.
Villa also emphasized that habitats are in dry rather than moist environments, and activity is opportunistic with heavy rainfall. Fenolio and Ready indicated a strong correlation between breeding and rainfall. James described in detail the habitat in Texas. No information is available for natural populations, but the soils where they burrow are often dry for weeks or months, so aestivation is presumed during such periods.
James noted western narrow-mouthed toads Gastrophryne olivacea , Texas toads Bufo speciosus , and Gulf Coast toads B. Adults reach sexual maturity at 60—65 mm Fouquette, with larger animals to 88 mm Nelson and Nickerson, Females tend to be larger than males. Feeding Behavior. Burrowing toads specialize in feeding on ants and termites in their underground nests.
Hindlimbs have keratinized tubercles used in burrowing, and front limbs and snout are specially adapted for entering termite and ant tunnels to access prey Trueb and Gans, ; Garrett and Barker, The tongue protrusion mechanism is uniquely designed for feeding on these insects underground Trueb and Gans, Anti-Predator Mechanisms.
Burrowing toads will grossly inflate their bodies, nearly concealing their head and limbs Garrett and Barker, This is useful for subterranean burrowing Trueb and Gans, and may also discourage predation on the surface. Other burrowing anurans e.
Santos-Barrera reported opalinid protozoans Zelleriela sp. Burrowing toads are considered Threatened by Texas, the only U. Federal Government. Because these are secretive animals, determining their distribution and abundance, and therefore their conservation status, is a problem. There are no data that indicate changes in abundance or distribution over the 35 yr they have been known from the Texas localities.
Mexican burrowing toad
Box Tempe, Arizona jack. Conservation Status definitions. Use NatureServe Explorer to see status. View distribution map using BerkeleyMapper.