Biology:Scaphiopus holbrookii

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Short description: Species of amphibian

Scaphiopus holbrookii
Scaphiopus holbrookii1-.jpg
Scientific classification edit
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Scaphiopodidae
Genus: Scaphiopus
Species:
S. holbrookii
Binomial name
Scaphiopus holbrookii
(Harlan, 1835)
Synonyms
  • Rana holbrookii Harlan, 1835
  • Scaphiopus solitarius Holbrook, 1836
  • Scaphiopus holbrookii – Cope, 1889

Scaphiopus holbrookii, commonly known as the eastern spadefoot, is a species of American spadefoot toad (family Scaphiopodidae) endemic to the eastern United States. It is not considered a true toad.[1][2][3]

Taxonomy

The epithet, holbrookii, is in honor of John Edwards Holbrook, American herpetologist.[4] A similar species is Hurter's spadefoot toad, which was once considered a subspecies of S. holbrookii.[5]

Unlike some other spadefoot toad species, such as Spea multiplicata (the Mexican or desert spadefoot) or Spea bombifrons (the plains spadefoot toad), Scaphiopus holbrookii never naturally develop cannibal tadpoles through phenotypic plasticity. Researchers at the University of North Carolina at Chapel Hill believe this is because the eastern spadefoot is most representative of the first spadefoot toads to evolve.[6][7]

Distribution and habitat

It is mostly found in the southeastern United States, except for mountainous areas, and is also found northward along the Atlantic coast into southern New England, where it is considered rare. It is found in inland states such as Pennsylvania and New York, but only as far westward as the Appalachian Mountains, and the Hudson River Valley in New York.[8]

Research has looked into the habitat selection of the species, and has found that it tends to hover around upland areas. It has shown preference for being close to deciduous shrub edges, low-growing pitch pine branches, and reindeer lichen. This environment provides an easy place to burrow land, with dense prey biomass, and protection from predators.[9]

Description

An American eastern spadefoot.

The average length of an adult eastern spadefoot is 44–57 mm (1 3⁄4–2 1⁄4 in). It is brownish in color, with two yellowish stripes on its back. These stripes, which begin on the upper eyelids, may diverge or converge, resulting in a pattern resembling a lyre or an hourglass. Some specimens may be very dark, with less distinct markings. [8] The skin is normally smoother and moister than other toads. [10] The eastern spadefoot belongs in one of only four groups of burrowing terrestrial anurans. [11] It has one spur on each of its back feet for burrowing.[5] The spur is generally three times longer than the other toes. [12]

Behavior

Scaphiopus holbrookii spends almost all of its life deep underground; emerging only to breed or feed. It remains in a type of hibernation almost all its life. It burrows in a spiral.[13]

One study used Passive Integrated Transponders (PIT tags) to monitor their emergence of burrows. The study found that S. holbrookii emerge about 43% of the nights they were monitored. They are much more likely to emerge if they had emerged the night prior as well. They also tended to emerge more frequently from their burrows on nights that were warmer and more humid, or the night after/during rain. Other than the emergence after rain and during breeding season, these animals do not have a specific pattern to their burrow emergence; the movements seem to be very random. [14]

Diet

Although Scaphiopus holbrookii is both diurnal and nocturnal, most foraging for food sources, consisting of small invertebrates such as termites, insects, arachnids, worms, is completed during the day. Some species will completely leave to burrow in search of prey; however, a common tactic for the eastern spadefoot is to simply sit at the opening of the burrow and wait for prey to pass by. [15]

Reproduction

S. holbrookii requires fish-free ephemeral ponds for breeding but occupies other habitats such as longleaf pine and wiregrass ecosystems when not breeding.[3] Eastern spadefoot toads are explosive breeders during sufficient rainfall and eggs are usually attached to submerged vegetation.[16] The eastern spadefoot toad can breed in almost any month of the year.[13] Due to the explosive breeding, once eggs hatch often food becomes limited from the large populations of tadpoles. S. holbrookii tadpoles are known to be omnivorous. In the event of food shortages some larva adapt aggressive feeding habits consuming large animal prey including other S. holbrookii tadpoles. These cannibalistic morphs develop a heightened rate and become much larger tadpoles in comparison to the non-cannibal morphs.[17]

Conservation status

While not listed as an endangered species by the U.S. federal government, S. holbrookii is considered "threatened" in Massachusetts [18] and Connecticut.[19] In that state and in 13 others, it is listed as a "Species of Greatest Conservation Need".[20]

References

  1. ↑ 1.0 1.1 IUCN SSC Amphibian Specialist Group (2022). "Scaphiopus holbrookii". IUCN Red List of Threatened Species 2022: e.T59042A196336701. doi:10.2305/IUCN.UK.2022-1.RLTS.T59042A196336701.en. https://www.iucnredlist.org/species/59042/196336701. Retrieved 12 May 2023. 
  2. ↑ Frost, Darrel R. (2015). "Scaphiopus holbrookii (Harlan, 1835)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Anura/Scaphiopodidae/Scaphiopus/Scaphiopus-holbrookii. Retrieved 4 January 2016. 
  3. ↑ 3.0 3.1 Greenberg, Cathryn H.; Tanner, George W. (2004-12-01). "Breeding Pond Selection and Movement Patterns by Eastern Spadefoot Toads (Scaphiopus holbrookii) in Relation to Weather and Edaphic Conditions" (in en). Journal of Herpetology 38 (4): 569–577. doi:10.1670/5-04A. ISSN 0022-1511. https://digital.library.unt.edu/ark:/67531/metadc777321/. 
  4. ↑ Bo Beolens; Michael Watkins; Michael Grayson (22 April 2013). The Eponym Dictionary of Amphibians. Pelagic Publishing. pp. 96. ISBN 978-1-907807-44-2. https://books.google.com/books?id=QJY3BAAAQBAJ&pg=PA96. 
  5. ↑ 5.0 5.1 "Eastern Spadefoot Toad". http://www.enature.com/fieldguides/detail.asp?allSpecies=y&searchText=Spade%20foot%20toad&curGroupID=7&lgfromWhere=&curPageNum=2. Retrieved 28 March 2016. 
  6. ↑ Pennisi, Elizabeth (28 November 2018). "Cannibalistic tadpoles and matricidal worms point to a powerful new helper for evolution" (in English). American Association for the Advancement of Science. https://www.science.org/content/article/cannibalistic-tadpoles-and-matricidal-worms-point-powerful-new-helper-evolution. Retrieved 10 September 2020. 
  7. ↑ Levis, N.A.; Isdaner, A.J.; Pfennig, D.W. (2018). "Morphological novelty emerges from pre-existing phenotypic plasticity". Nature Ecology & Evolution 2 (8): 1289–1297. doi:10.1038/s41559-018-0601-8. PMID 29988161. 
  8. ↑ 8.0 8.1 Conant, Roger. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Second Edition. Houghton Mifflin. Boston. 429 pp. ISBN:0-395-19977-8 (pbk.) (Scaphiopus holbrooki holbrooki, p. 299 + Plate 44 + Map 253.)
  9. ↑ Timm, Brad C., et al. “Upland Movement Patterns and Habitat Selection of Adult Eastern Spadefoots (Scaphiopus holbrookii) at Cape Cod National Seashore.” Journal of Herpetology, vol. 48, no. 1, 2014, pp. 84–97. doi:10.1670/12-201
  10. ↑ Overduijn, K. (n.d.). Eastern spadefoot toad (scaphiopus holbrookii). Species Profile: Eastern Spadefoot Toad (Scaphiopus holbrookii) | SREL Herpetology. Retrieved 11 February 2023.[1]
  11. ↑ https://palaeo-electronica.org/content/content/2015/1299-neoichnology-of-toads. Johnson, L. M., & Hembree, D. I. (2015). Neoichnology of the eastern spadefoot toad, Scaphiopus holbrookii (Anura: Scaphiopodidae): criteria for recognizing anuran burrows in the fossil record. Palaeontologia Electronica, 18(2), 1-29.
  12. ↑ https://repositories.lib.utexas.edu/bitstream/handle/2152/45000/0070_Scaphiopus_holbrookii.pdf?sequence=1 Wasserman, A. O. (1968). Scaphiopus holbrookii. Catalogue of American Amphibians and Reptiles (CAAR). Retrieved February 11, 2023
  13. ↑ 13.0 13.1 Erickson, M.R., Scott, D.E., Jones, K.L. et al.; Development and characterization of ten microsatellite loci for the eastern spadefoot toad, Scaphiopus holbrookii. Conservation Genetics Resources 2, 143–145 (2010). doi:10.1007/s12686-010-9198-1
  14. ↑ Ryan, Calhoun, A. J. K., Timm, B. C., & Zydlewski, J. D. (2015). Monitoring Eastern Spadefoot (Scaphiopus holbrookii) Response to Weather with the Use of a Passive Integrated Transponder (PIT) System. Journal of Herpetology, 49(2), 257–263. doi:10.1670/12-230
  15. ↑ Smith, Tristan. "Scaphiopus holbrookii (Eastern Spadefoot)" (in en). https://animaldiversity.org/accounts/Scaphiopus_holbrookii/#:~:text=Food%20Habits,%3A%200.002%2D2.04m).. 
  16. ↑ "Virginia Herpetological Society" (in en). http://www.virginiaherpetologicalsociety.com/. 
  17. ↑ "Meet the larval amphibians that morph to become cannibals" (in en). 2019-06-26. https://www.nationalgeographic.com/animals/article/cannibal-morph-amphibians-adapt. 
  18. ↑ "Eastern Spadefoot Scaphiopus holbrookii" (pdf). Massachusetts Division of Fisheries & Wildlife. 2015. https://www.mass.gov/doc/eastern-spadefoot/download. Retrieved 5 May 2020. 
  19. ↑ Moran, Katherine, and Charles E. Button. "A GIS model for identifying eastern spadefoot toad (Scaphiopus holbrookii) habitat in eastern Connecticut." Applied Geography 31.3 (2011): 980-989. doi:10.1016/j.apgeog.2011.01.004
  20. ↑ "USGS map of S. holbrookii by state wildlife action plan (SWAP)" (dynamic map). USGS. https://www1.usgs.gov/csas/swap/species_view.html?sciname=Scaphiopus%20holbrookii. Retrieved 5 May 2020. 

External links

Wikidata ☰ Q932943 entry



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