The southern painted turtle (''Chrysemys dorsalis'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

in the family

Emydidae Emydidae (Latin ''emys'' (freshwater tortoise) + Ancient Greek εἶδος (''eîdos'', “appearance, resemblance”)) is a family of testudines (turtles) that includes close to 50 species in 10 genera. Members of this family are commonly calle ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the south-central

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

Taxonomy

The southern painted turtle was formerly considered a subspecies of the more widespread

painted turtle The painted turtle (''Chrysemys picta'') is the most widespread native turtle of North America. It lives in slow-moving fresh waters, from southern Canada to northern Mexico, and from the Atlantic to the Pacific. They have been shown to prefer l ...

(''C. picta'') as ''C. picta dorsalis'', and its exact status is still debated. Since the 1950s, the southern painted turtle, alongside the subspecies of ''C. picta'', was generally thought to have originated following

geographic isolation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

as a result of the

Quaternary glaciation The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describe ...

, with the populations being isolated for too short a time to fully diverge into distinct species. However, David E. Starkey and collaborators advanced a new view of the subspecies in 2003. Based on a study of the

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

, they rejected the glacial development theory and argued that the southern painted turtle should be elevated to a separate species, ''C. dorsalis'', while the other subspecies should be collapsed into one and not differentiated. However, this proposition was largely unrecognized because successful breeding between all subspecies was documented wherever they overlapped. Nevertheless, in 2010, the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

recognized both ''C. dorsalis'' and ''C. p. dorsalis'' as valid names for the southern painted turtle. In 2014, the

Turtle Taxonomy Working Group The Turtle Taxonomy Working Group (TTWG) is an informal working group of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group (TFTSG). It is composed of a number of leading turtle taxonomists, with varying participation by individual partici ...

((TTWG) and the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...

reclassified ''C. dorsalis'' as a distinct species, although the TTWG also recognized ''C. p. dorsalis'' as a valid name. The TTWG continued to recognize ''C. dorsalis'' as a distinct species in their 2021 publication.

Description

The smallest member of ''Chrysemys'', it is smaller than any of the subspecies of ''C. picta'' at about long. Its top stripe is a prominent red, and its bottom shell is tan and spotless or nearly so.

Ecology

This species' diet changes with age. Juveniles' diet consists of 13% vegetation, while the adults eat 88% vegetation. This perhaps shows that the turtle prefers small larvae and other prey, but can only obtain significant amounts while young. The reversal of feeding habits with age has also been seen in the

false map turtle The false map turtle (''Graptemys pseudogeographica'') is a species of turtle endemic to the United States. It is a common pet species. Two subspecies are recognized, including the nominotypical subspecies described here. Description Also know ...

, which inhabits some of the same range. The most common plants eaten by adult southern painted turtles are

duckweed Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose ...

and algae, and the most common prey items are dragonfly larvae and

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

Distribution

The southern painted turtle ranges from extreme southern Illinois and Missouri, roughly along the Mississippi River Valley, to the south. In Arkansas, it branches out to the west towards Texas, where it is found in the far northeast part of that state (

Caddo Lake Caddo Lake (french: Lac Caddo) is a lake and bayou (wetland) on the border between Texas and Louisiana, in northern Harrison County and southern Marion County in Texas and western Caddo Parish in Louisiana. The lake is named after the Caddoan ...

region) as well as extreme southeastern Oklahoma (

McCurtain County McCurtain County is in the southeastern corner of the U.S. state of Oklahoma. As of the 2010 census, the population was 33,151. Its county seat is Idabel. It was formed at statehood from part of the earlier Choctaw Nation in Indian Territory ...

). It is found in much of Louisiana, where it reaches the Gulf of Mexico (in fresh water). Eastward it is found in western Tennessee, northern Mississippi and much of Alabama, including the Gulf Coast city of Mobile. An isolated population in central Texas has been reported but is now believed to be non-native.

Life history

It has a smaller clutch size than ''C. picta'', at about 4.2 eggs per clutch.

References

Chrysemys Turtles of North America Reptiles of the United States Endemic fauna of the United States Reptiles described in 1857 Taxa named by Louis Agassiz {{Taxonbar, from=Q2381029