Box turtle

From Wikipedia, the free encyclopedia - View original article

Box turtle
Temporal range: miocene - Recent, 15–0 Ma
Florida box turtle, Terrapene carolina bauri
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
Class:Reptilia
Order:Testudines
Family:Emydidae
Genus:Terrapene
Merrem, 1820[1]
Type species
Terrapene carolina
(Linnaeus, 1758)
Species[1]

Terrapene carolina
Terrapene coahuila
Terrapene nelsoni
Terrapene ornata

Synonyms[2]

Cistuda Fleming, 1822
Diducla Rafinesque, 1832
Pyxidemys Fitzinger, 1835
Emyoides Gray, 1844
Onychotria Gray, 1849
Pariemys Cope, 1895
Toxaspis Cope, 1895

 
Jump to: navigation, search
Box turtle
Temporal range: miocene - Recent, 15–0 Ma
Florida box turtle, Terrapene carolina bauri
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
Class:Reptilia
Order:Testudines
Family:Emydidae
Genus:Terrapene
Merrem, 1820[1]
Type species
Terrapene carolina
(Linnaeus, 1758)
Species[1]

Terrapene carolina
Terrapene coahuila
Terrapene nelsoni
Terrapene ornata

Synonyms[2]

Cistuda Fleming, 1822
Diducla Rafinesque, 1832
Pyxidemys Fitzinger, 1835
Emyoides Gray, 1844
Onychotria Gray, 1849
Pariemys Cope, 1895
Toxaspis Cope, 1895

The box turtle (Terrapene), or box tortoise[3] is a genus of turtle native to North America (United States and Mexico). The 12 taxa which are distinguished in the genus are distributed over four species. It is largely characterized by having a domed shell, which is hinged at the bottom, allowing the animal to close its shell tightly to escape predators. Box turtles have become popular pets, although their needs in captivity are complex.

Contents

Taxonomy and genetics

The genus name Terrapene was coined by Merrem in 1820 as a separate genus from the Emydes for those species which had a sternum which was separated into two or three divisions and which could move these parts independently.[4] He placed in this genus amongst others Terrapene boscii (now accepted to be Kinosternon subrubrum subrubrum) and Terrapene carolina (but under the name Terrapene clausa). Also several Asian box turtles have been (mis)classified within the genus Terrapene: e.g. Terrapene bicolor (now Cuora amboinensis couro) and Terrapene culturalia (now Cuora flavomarginata).[1] Currently four species are classified within the genus and twelve taxa are distinguished:[1]

Box turtles have diploid somatic cells with 50 chromosomes.[6]

Description

Size difference between the two subspecies of Terrapene ornata: T.c.ornata (left) and T.c.luteola (right).
Plastron of T.c.carolina showing the hinge (H) between abdominal (abd) and pectoral (pect) scales. Also the other scales (an=anal, fem=femural, hum=huminal, gul=gular) are shown.

All box turtles have a highly domed carapace. All species are domed, with a first central scute at an angle of more than 50° while the next central scutes are often flattened. While T. carolina species have a prominent medial keel (a ridge over the length of the carapace), this feature is (nearly) absent in the other species. As a result of the hinge in their plastron (between the abdominal and pectoral scales), box turtles can close very tightly to protect themselves from predators. The plastral formula (size relation between the scales) varies between species, but the order of the largest three scutes is anal > abdominal > gular in all species.[6][7][8][9] The ability to close develops when it is one quarter grown and is generally only lost due to corpulence.[10] Based on morphological characteristics, two distinct lineages can be distinguished: the ornata/nelsoni lineage as well as the carolina/coahuila cluster.[5] The ornata/nelsoni cluster is the smallests (maximum carapace lengths of 14–15 cm), while the other cluster is larger (with T.c.major with a carapace length of 20 cm). The radiation pattern varies strongly: from the none-patterned C. coahuila, to the characteristic stripes in C. ornata and the yellow/brown spots in C. nelsoni. C. carolina is the most varied genus with spots, bars and lines which pattern often also varies from scute to scute.[6]

To distinguish between a male and a female box turtle, it is simplest to turn the turtle over and examine its plastron. The male usually has a concave area centered posterior to the hinge. This adaptation apparently aids the male's ability to climb on top of the female during mating. The one pictured above left is a male.

Ecology and behaviour

Three images of eastern box turtles laying eggs
T. c. carolina laying eggs

Life cycle and predation

Rings on the scutes of T.c.triunguis. Rings can be used to estimate the age of box turtles in their early years.

Once maturity is reached, the chance of death seems not to increase with age. The survivorship curve of box turtles is therefore probably similar to that of other long-living turtles. The average life span of adult box turtles is 50 years, while a significant proportion lives over 100 years. The age of a growing box turtle in the wild can be roughly estimated by counting the growth rings on the scutes; the plastron is the best place to do this because it also allows examination of wear pattern. However, the rate of 1 ring per growth season has not been fully confirmed, and estimates beyond 20 years are unreliable because the scutes is usually worn smooth.[11] Box turtle eggs are flexible, oblong and are (depending on the taxon) on average 2–4 cm long weighing 5-11 g. The normal clutch size is 1-7 eggs. In captivity and in the southern end of their range, box turtles can have more than one clutch per year, while the average clutch size is larger in more northern populations.[12] Turtles can defend themselves from predation by hiding, closing their shell and biting. The risk of death is greatest in small animals due to their size and weaker carapace and plastron. While the shell of an adult box turtle is impenetrable to virtually any animal, they do not always close in a case of threat. Common predators are mammals like minks, skunks, raccoons, dogs and rodents, but also birds (e.g. crows, ravens) and snakes (e.g. racers, cottonmouths) are known to kill box turtles.[13]

Diet

North American box turtles are omnivores with a very varied diet as box turtles "basically eat anything it can catch". Invertebrates (amongst others insects, earth worms, millipedes) form the principal component, but the diet also consists for a large part (reports range from 30-90%) of vegetation. The diet is amended with fruits (amongst others from cacti, apples and several species of berry), gastropods (Heliosoma, Succinea).[14] While reports exist that during their first five to six years, box turtles are primarily carnivorous, while adults are mostly herbivorous, there is no scientific basis for such a difference.[14]

Distribution and habitat

Distribution map
Distribution of the four species of Terrapene

Box turtles are native to North America. The widest distributed species is the common box turtle which is found in the United States (subspecies carolina, major, bauri, triunguis; South-Central, Eastern and South Eastern parts) and Mexico (subspecies yukatana and mexicana; Yucatán peninsula and North Eastern parts). The Ornate box turtle is endemic to the south-central and South Western parts of the U.S. (and adjacent Mexico) while the spotted box turtle is endemic to North-Western Mexico only. The coahuilan box turtle is only found in Cuatro Ciénegas Basin (Coahuila, Mexico).[2]

Habitat

Because box turtles occupy a wide variety of habitats (which both vary on a day-to-day, season-to-season, but also species-to-species basis), a standard box turtle habitat can not be identified. Mesic woodlands are a habitat where box turtles are generally found. T. ornata is the only species regularly found in grasslands, but its subspecies the desert box turtle is also found in the semidesert with rainfall predominantly in summer. The single location where Coahuilan box turtles are found is a 360 km2 region characterized by marshes, permanent presence of water and several types of cacti.

Prior to hibernation, box turtles tend to move further into the woods, where they dig a chamber for overwintering. Ornate box turtles dig chambers up to 50 centimeters, while Eastern box turtles hibernate at depth of about 10 centimeters. The location for overwintering can be up to 0.5 km from the summer habitat and is often in close proximity to that of the previous year. In more southern locations, turtles are active year-round, as has been observed for T. coahuila and T.c.major'. Others box turtles in higher temperatures are more active (T.c.yukatana) or only active during the wet seasons.[15]

Evolution

Box turtles appeared "abruptly in the fossil record, essentially in modern form". The absence of strong changes in their morphology might indicate that they are a generalist species.[5] It is therefore complicated to establish how their evolution from other turtles took place. The oldest finds of fossilized box turtles were found in Nebraska (U.S.), date from about 15 million years before present (in the miocene)[5] and resemble the aquatic species T. coahuila most, which indicates that the common ancestor was also an aquatic species. Fossilized specimens of T. ornata and T. carolina were dated circa 5 million years before present and indicated that those main lineages also already diverged within the miocene. The only recognized extinct subspecies (T.c. putnami) dates from the pliocene and was with a carapace length of 30 cm much larger than any other species.[5]

Interaction with humans

Conservation status

As the conservation status is defined for species and not for a genus, differences exist between the different genera. Terrapene coahuila is -as it is endemic only to Coahuila- classified as endangered. While the range reduced with 40% to 360 km2 in the past 40–50 years, the number of species reduced from "well over 10,000" to circa 2,500 in 2002.[16] The most widely distributed species Terrapene carolina is classified as vulnerable, while Terrapene ornata is in a lower category as near threatened.[17][18] For Terrapene nelsoni not sufficient information is available for classification.[19]

Sniffer dogs have been trained to find and track box turtles as part of conservation efforts.[20]

Box turtles as pets

Most turtle and tortoise societies recommend against box turtles as pets for small children.[citation needed] Box turtles are easily stressed by over-handling and require more care than is generally thought. Box turtles can be injured by dogs and cats so special care must be taken to protect them from household pets. Box turtles require an outdoor enclosure, consistent exposure to the sun and a varied diet. Without these, a turtle's growth can be stunted and its immune system weakened.

A 3-year study in Texas indicated that over 7,000 box turtles were taken from the wild for commercial trade. A similar study in Louisiana found that in a 41-month period, nearly 30,000 box turtles were taken from the wild for resale. Once captured, turtles are often kept in poor conditions where up to half of them die. Those living long enough to be sold may suffer from conditions such as malnutrition, dehydration, and infection.[21][22]

Indiana and other states have laws against collecting the turtles from the wild. In many states, it is illegal to keep them without a permit. Collecting box turtles from the wild may damage their populations, as these turtles have a low reproduction rate.[23]

State reptiles

"The turtle watches undisturbed as countless generations of faster 'hares' run by to quick oblivion, and is thus a model of patience for mankind, and a symbol of our State’s unrelenting pursuit of great and lofty goals."

North Carolina Secretary of State[24]

Box turtles are official state reptiles of four U.S. states. North Carolina and Tennessee honor the eastern box turtle.[25][26][27] Missouri names the three-toed box turtle.[28] Kansas honors the ornate box turtle.[29][30]

In Pennsylvania, the eastern box turtle made it through one house of the legislature, but failed to win final naming in 2009.[31] In Virginia, bills to honor the eastern box turtle failed in 1999 and then in 2009. For the most recent failure, a Republican legislator criticized the creature for being cowardly because of its shell. However, the main problem in Virginia was that the creature was too closely linked to neighbor state North Carolina.[32][33]

See also

External links

References

  1. ^ a b c d Rhodin 2010, pp. 000.106-107
  2. ^ a b c Fritz 2007, p. 196
  3. ^ "tortoise Box tortoise". Dictionary.com. http://dictionary.reference.com/browse/Box%20. Retrieved 21 February 2011. 
  4. ^ Blasius Merrem. "Versuch eines Systems der Amphibien" (in German). Johann Christian Krieger. http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Merrem_1820.pdf. 
  5. ^ a b c d e KDodd, pp. 24-30
  6. ^ a b c C.H. Ernst, R.G.M. Altenburg and R.W. Barbour. "Terrapene carolina". Netherlands Biodiversity Information Facility. http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=317. Retrieved 12 February 2011. 
  7. ^ C.H. Ernst, R.G.M. Altenburg and R.W. Barbour. "Terrapene ornata". Netherlands Biodiversity Information Facility. http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=318. Retrieved 13 February 2011. 
  8. ^ C.H. Ernst, R.G.M. Altenburg and R.W. Barbour. "Terrapene coahuila". Netherlands Biodiversity Information Facility. http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=316. Retrieved 13 February 2011. 
  9. ^ C.H. Ernst, R.G.M. Altenburg and R.W. Barbour. "Terrapene nelsoni". Netherlands Biodiversity Information Facility. http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=319. Retrieved 13 February 2011. 
  10. ^ Richard D. Bartlett, Patricia Pope Bartlett (2001). Box Turtles. Barron's educational Services. http://books.google.nl/books?id=sX2F7nRs7W0C&lpg=PT11&dq=%22terrapene%22%20hinge&pg=PT11#v=onepage&q=%22terrapene%22%20hinge&f=false. Retrieved 13 February 2011. 
  11. ^ KDodd, p. 126
  12. ^ KDodd, pp. 103-105
  13. ^ KDodd, p. 140
  14. ^ a b KDodd, pp. 114-116
  15. ^ KDodd, p. 60
  16. ^ van Dijk, P.P., Flores-Villela, O. & Howeth, J. (2007). "Terrapene coahuila". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/21642. Retrieved 13 Feb 2011. 
  17. ^ Tortoise & Freshwater Turtle Specialist Group 1996 (1996). "Terrapene carolina". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/21641. Retrieved 20 July 2011. 
  18. ^ Tortoise & Freshwater Turtle Specialist Group 1996 (1996). "Terrapene ornata". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/21644. Retrieved 13 Feb 2011. 
  19. ^ Tortoise & Freshwater Turtle Specialist Group 1996 (1996). "Terrapene nelsoni". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/21643. Retrieved 13 Feb 2011. 
  20. ^ Ray, Julie (2011-07-31). "Service Dogs Find Endangered Species". http://greenanswers.com/blog/254326/service-dogs-find-endangered-species. Retrieved 4 August 2011. 
  21. ^ http://www.btpt.org/pubs/BTPT_faq.pdf
  22. ^ TTN 1:19
  23. ^ McCallum, M.L., J.L. McCallum, S.E. Trauth. 2009. Box turtles generally stay within the same area where they were born. If one is moved more than a half-mile from its territory, it may never find its way back. This may disrupt their breeding cycle. Predicted climate change may spark box turtle declines. Amphibia-Reptilia 30:259-264
  24. ^ "Eastern Box Turtle – North Carolina State Reptiles". North Carolina Department of the Secretary of State. http://www.secretary.state.nc.us/pubsweb/symbols/sy-turtl.htm. Retrieved 2011-02-13. 
  25. ^ Shearer 1994, p. 321
  26. ^ "Official State Symbols of North Carolina". North Carolina State Library. State of North Carolina. http://ncpedia.org/symbols/reptile. Retrieved 2008-01-26. 
  27. ^ "Tennessee Symbols And Honor" (PDF). Tennessee Blue Book: 526. http://www.state.tn.us/sos/bluebook/07-08/46-Symbols%20&%20Honors.pdf. Retrieved 2011-01-22. 
  28. ^ "State Symbols of Missouri: State Reptile". Missouri Secretary of State Robin Carnihan. http://www.sos.mo.gov/symbols/symbols.asp?symbol=reptile. Retrieved 2011-01-21. 
  29. ^ Shearer 1994, p. 315
  30. ^ "2009-73-1901 Kansas Code patriotic emblems, state reptile, designation". Justia. http://law.justia.com/kansas/codes/2009/chapter73/statutes_31572.html. Retrieved 2011-02-11. 
  31. ^ "Regular Session 2009–2010: House Bill 621". Pennsylvania State Legislature. http://www.legis.state.pa.us/cfdocs/billinfo/bill_history.cfm?syear=2009&sind=0&body=H&type=B&bn=621. Retrieved 2011-02-25. 
  32. ^ "SB 1504 Eastern Box Turtle; designating as official state reptile". Virginia State Legislature. https://leg1.state.va.us/cgi-bin/legp504.exe?091+sum+SB1504. Retrieved 2011-02-25. 
  33. ^ Associated Press (2009-02-20). "Virginia House crushes box turtle's bid to be state reptile". NBC Washington. http://www.nbcwashington.com/news/local/Virginia-House-Crushes-Box-Turtles-Bid-to-Be-State-Reptile.html. Retrieved 2011-02-25. 
Bibliography