Sternotherus
Sternotherus | |
---|---|
Sternotherus odoratus eastern musk turtle, hatchling | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Cryptodira |
Family: | Kinosternidae |
Subfamily: | Kinosterninae |
Genus: | Sternotherus Bell in Gray, 1825[1] |
Sternotherus is a genus of turtles in the family Kinosternidae including six species commonly known as musk turtles. The genus is endemic to North America, occurring in the eastern third of the US and southeast Ontario, Canada. Musk glands positioned near the bridge of the shell can produce foul smelling secretions when the turtles are threatened, although gentle handling does not normally provoke a response. Sternotherus are moderately small turtles, with the largest species in the genus, the razor-backed musk turtle (S. carinatus), attaining a maximum of 17.6 cm. in shell length. The carapace is characteristically oval and domed (an exception being the flattened musk turtle, S. depressus), with most species having one or three keels on the back which may become smoother and obscure with age in some species. Musk turtles are generally drab in color, mostly black, gray, brown, olive, or ocher, which aid in camouflaging them in their natural habitats. The head is relatively large and stout, marked with spots, streaks, or strips. The plastron has only 10 or 11 scutes, as opposed to 12, a more common condition in North American turtles. The tail is short, with males having a horny claw like tip.
Sternotherus are largely aquatic, however some species frequently bask on fallen logs or rocks emerging from the water, and eastern musk turtles (S. odoratus) occasionally leave the water to forage. Sternotherus are omnivorous and opportunistic generalist in their diet, although inclining toward being carnivorous, with mollusks (gastropods and bivalves) and insects making up a significant percentage of their diet. Some older adults develop large musculature on the head and expanded, crushing jaw surfaces aiding in the consumption of mollusk. Musk turtles are oviparous with females producing one to six clutches a year. The typical clutch size is two to four eggs, although clutches may range from one to 13. The sex of the hatchlings is determined by the incubation temperature. The eggs are deposited in shallow nest excavated on the banks or in woodlands a few meters from the water. Eggs may be laid singly, or in groups, and some species are known to share communal nesting areas.[2]: 471–472, 511–535 pp.
Etymology
The generic name Sternotherus is Greek meaning hinged breast or chest, referring to the hinged
Taxonomy
Sternotherus is one of four genera in the family Kinosternidae including: narrow-bridged musk turtles (Claudius), American mud turtles (Kinosternon), giant musk turtles (Staurotypus), and musk turtles (Sternotherus). Sternotherus are closely related, similar in appearance, and sympatric in much of their range with some species of mud turtles (Kinosternon), and the two genera constitute the subfamily Kinosterninae within the family Kinosternidae. In the past some taxonomist placed Sternotherus in the synonymy of the genus Kinosternon[9][10] but they are generally regarded as two separate genera with six species currently (2022) recognized in the genus Sternotherus.[11]
Genus
Extant species
- Sternotherus carinatus (Gray, 1855)[13] – razor-backed musk turtle
- Sternotherus depressus Tinkle & Webb, 1955[14] – flattened musk turtle
- Sternotherus intermedius Scott, Glenn & Rissler, 2018[6] – intermediate musk turtle
- Sternotherus minor (Agassiz, 1857)[15] – loggerhead musk turtle
- Sternotherus odoratus (Latreille, 1801)[16] – eastern musk turtle[17]
- Sternotherus peltifer (H.M. Smith & Glass, 1947)[18] – stripeneck musk turtle
Fossil species
- †Sternotherus palaeodorus (Bourque & Schubert, 2015)[19] (known from the Miocene—Pliocene fossil remains)
Nota bene: A binomial authority in parentheses indicates that the species was originally described in a genus other than Sternotherus.
Description
Turtles in the genus Sternotherus are very similar to the American
Distribution
The genus Sternotherus is endemic to North America. It occurs in the approximant eastern third of the US and extreme southeast Ontario, Canada. The eastern musk turtle (S. odoratus), the most wide-ranging species of the genus, occurs in southern Maine, south to Florida, west into eastern Texas, Oklahoma, and Kansas, and north to southeast Wisconsin, southern Michigan, and the Great Lakes region of southern Ontario. It is generally absent from higher elevations in the Appalachian Mountains.
The other species in the genus largely occur within the southern regions of the eastern musk turtle's range. Two species have relatively limited distributions, the flattened musk turtle (S. depressus) is endemic to north-central
Ecology and natural history
Diet: Sternotherus are omnivorous. The loggerhead (S. minor) and stripe-necked musk turtle (S. peltifer) have been described as opportunistic generalist tending toward carnivory. Mollusk make up a significant portion of the diet in all species, particularly adults. Juveniles and sub-adults (under 5 cm.) feed on a higher percentage of aquatic insects, algae, and carrion. An ontogenetic change in diet occurs and adults shift to an omnivorous diet with a high percentage of mollusk. Food items include mollusks (gastropods and bivalves), insects (including larva, adults, aquatic and terrestrial), crustaceans (crayfish and crabs), worms (earthworms and leeches), amphibians (tadpoles and small frogs), carrion, filamantous green algae, parts of vascular plants and seeds (e.g. Prunus, Sambucus, Ulmus, Podostemum). Some novel and less common documented food items include spiders, millipedes, small fish and fish eggs, isopods, and small turtles. The flattened musk turtle (S. depressus) is known to feed on introduced Asian clams (Corbicula maniliensis).[2]: 513, 516, 523, 533 pp. [21][22]
The razor-backed (S. carinatus) and eastern musk turtles (S. odoratus) are known to be bottom feeders, often searching with the neck extended and probing the mud and sand with their heads.
Habitat:Sternotherus are largely aquatic, but some species bask frequently, and may occasionally leave the water to forage and lay eggs. Fallen logs and deadwood submerged and emerging from the water are important for shelter and basking sites for all species of Sternotherus. Habitat preferences varies among some species. The eastern musk turtle (S. odoratus) tends to be generalist and may occur in almost any body of water, as are loggerheads (S. minor) to a lesser extent, although water with slow or no currents, soft bottoms, and shelter in the form of logs and rocks are usually preferred over very deep water and swift currents. Eastern musk turtles have been found at depths of 9 meters but, shallower water (ca. 1 meter), are more typical. Brackish water is usually avoided. Depths of 0.5–1.5 meters are typical for loggerheads (S. minor), but they have been found at 13 meters.
In one ecological study of
Behavior: Sternotherus is a highly aquatic genus. But some species, like the
Gallery
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Razorback musk turtle (Sternotherus carinatus), Saline County, Arkansas (July 28, 2017)
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Razorback musk turtle (Sternotherus carinatus), in-situ, Hardin County, Texas (October 10, 2013)
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Eastern musk turtle (Sternotherus odoratus), in-situ, Kerr County, Texas (8 May 2014)
References
- ^ "Sternotherus ". ITIS (Integrated Taxonomic Information System). www.itis.gov.
- ^ ISBN 0-8018-9121-3
- ^ Zug, George. 1986. Sternotherus. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 397:1-3.
- ^ Iverson, John B. 1979. Sternotherus carinatus. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 226:1-2.
- ^ Iverson, John B. 1977. Sternotherus depressus. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 194: 1-2.
- ^ a b c Scott, Peter A., Travis C. Glenn, and , Leslie J. Rissler. 2017. Resolving taxonomic turbulence and uncovering cryptic diversity in the musk turtles (Sternotherus) using robust demographic modeling. Molecular Phylogenetics and Evolution. 120: 1-15.
- ^ a b Iverson, John B. 1977. Sternotherus minor. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 195: 1-2.
- ^ Reynolds, Samuel L. and Michael E. Seidel. 1982. Sternotherus odoratus. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 287: 1-4.
- ^ Iverson, John B., 1991. Phylogenetic hypotheses for the evolution of modern kinosternine turtles. Herpetological Monographs, No. 5: 1-27.
- ISBN 1-888089-23-7
- ^ Uetz, Peter, Paul Freed, , Aguilar, R. & Hošek, J. (eds.) (2021) The Reptile Database: http://www.reptile-database.org, (accessed March 5, 2022)
- ^ Bell, T. in Gray, John Edward. 1825. A synopsis of the genera of reptiles and Amphibia, with a description of some new species. Annals of Philosophy 10: 193-217.
- ^ Gray, John Edward. 1855 [1856]. Catalogue of Shield Reptiles in the Collection of the British Museum. Part I. Testudinata (Tortoises). Taylor and Francis, London, 79 pp.
- ^ Tinkle, Donald W., and Robert G. Webb 1955. A new species of Sternotherus with a discussion of the Sternotherus carinatus complex (Chelonia, Kinosternidae). Tulane Studies in Zoology 3 (3): 53.
- ^ Agassiz, Louis 1857. Contributions to the Natural History of the United States of America. Vol. 1. Little, Brown & Co., Boston, 452 pp.
- ^ Latreille, Pierre André. 1801 [1802]. In: C.N.S. Sonnini de Manoncourt and P.A. Latreille. Histoire Naturelle des Reptiles, avec Figures Déssinnées d'après Nature. Détérville, Paris, Vol. 1. xx + 280 p.
- ISBN 978-1-946681-00-3
- ^ Smith, Hobart M. & Bryan P. Glass. 1947. A new musk turtle for southeastern United States. Journal of the Washington Academy of Sciences 37 (1): 22-24.
- ^ Bourque, Jason R., and Blaine W. Schubert. 2015. Fossil musk turtles (Kinosternidae, Sternotherus) from the late Miocene–early Pliocene (Hemphillian) of Tennessee and Florida. Journal of Vertebrate Paleontology 35.1: e885441.
- ISBN 978-0-544-12997-9
- ^ Marion, Ken R., William A. Cox, and Carl H. Ernst. 1991. Prey of the flattened musk turtle, Sternotherus depressus. Journal of Herpetology 25.3 (1991): 385-387
- ^ a b c Mahmoud, I. Y. 1968. Feeding behavior in kinosternid turtles. Herpetologica, 24(4), 300-305.
- ^ Bancroft, G. Thomas, J. Steve Godley, Dena T. Gross, N. Nan Rojas, Dareth A. Sutphen, and Roy W. McDiarmid. 1983. Large-scale operations management test of use of the white amur for control of problem aquatic plants: the herpetofauna of Lake Conway: species accounts. Misc, Pap. A-85-5. Army Eng. Waterw. Exp. Stn. Vickburg, Mississippi.
- ^ Parmenter, Robert R. 1981. Digestive turnover rates in freshwater turtles: the influence of temperature and body size. Comparative Biochemistry and Physiology Part A: Physiology 70.2: 235-238.
- ^ Hensley, F. R. 1995. Sternotherus minor (loggerhead musk turtle) Foraging depth. Herpetological Review 26: 99.
- ^ a b Mahmound, I. Y. 1969. Comparative ecology of the kinosternid turtles of Oklahoma. Southwestern Naturalist 14: 31-66.
Further reading
- Bell T (1821). In: Gray JE (1821). "A Synopsis of the Genera of Reptiles and Amphibia, with a Description of some new Species". Annals of Philosophy, New Series [Second Series] 10: 193-217. (Sternotherus, new genus, p. 211).
- ISBN 0-7167-0020-4. (Genus Sternotherus, pp. 136, 263-264).
- ISBN 0-307-13666-3. (Genus Sternotherus, p.28).
External links
- Walker, Matt (2010). "Turtle 'super tongue' lets reptile survive underwater". BBC Earth News. 20 May 2010.
- Genus Sternotherus at The Reptile Database