The Baja California slider (''Trachemys nebulosa''), also known as the black-bellied slider, is

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

in the family

Emydidae Emydidae (Latin (freshwater tortoise) + Ancient Greek (, "appearance, resemblance")) is a family of testudines (turtles) that includes close to 50 species in 10 genera. Members of this family are commonly called terrapins, pond turtles, or mar ...

. It is native to

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Sinaloa Sinaloa (), officially the (), is one of the 31 states which, along with Mexico City, compose the Federal Entities of Mexico. It is divided into 18 municipalities, and its capital city is Culiacán Rosales. It is located in northwest Mexic ...

and

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

in Mexico.

Taxonomy

There are two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

recognised: *''Trachemys nebulosa nebulosa'' – from Baja California. *''Trachemys nebulosa hiltoni'' Fuerte slider – from Sinaloa and Sonoro.

Description

The Baja California slider is a medium-sized

and identified for their clawed digits, non-elephantine hind limbs and a wide-colored suborbital patch. They have smooth shells, rounded posteriorly and straight interiorly. These shells are longer than they are wide, have a low later profile and can reach up to 37 cm (14.5 inches) in length. On the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

side of the shell is yellow with symmetrical black markings.

Dorsally Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

the shell is dark in color with the

vertebral Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

, costal and marginal

scute A scute () or scutum (Latin: ''scutum''; plural: ''scuta'' "Scutum (shield), shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of Bird anatomy#Scales, birds. The ter ...

s having dark black spots surrounded by lighter margins. The Baja California slider has a large, triangular shaped head which is covered by smooth skin. They have protruding non-hooked

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, Rostrum (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...

s where the nostrils are located decently high and large eyes. The top of the head is olive colored with indistinct pale lines while the chin and throat are lighter with central yellow markings; there is a pair of yellow stripes that extend anteriorly across the local

jaw The jaws are a pair of opposable articulated structures at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth ...

and onto the upper jaw. Their tails are moderately long while male's tails being longer than females. The bodies are covered with multiple yellow stripes including the

forelimbs A forelimb or front limb is one of the paired articulated appendages ( limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used inst ...

, not the hind limbs.

Distribution and habitat

The Baja California slider has an exceedingly limited geographic range, currently found from

San Ignacio San Ignacio (the Spanish language name of St. Ignatius (disambiguation), St. Ignatius) is a common toponym in parts of the world where that language is or was spoken: Argentina * San Ignacio, Argentina, Misiones Province * San Ignacio Miní, a ...

southward into

Baja California Sur Baja California Sur, officially the Free and Sovereign State of Baja California Sur, is a state in Mexico. It is the 31st and last state to be admitted, in 1974. It is also the second least populated Mexican state and the ninth-largest state by ...

. They were endemic only to the Río San José basin in the greater

Cabo San Lucas Cabo San Lucas (, "Luke the Evangelist, Saint Luke Cape (geography), Cape"), also known simply as Cabo, is a Resort town, resort city at the southern tip of the Baja California peninsula, in the Mexican Political divisions of Mexico, state of Baja ...

area (where they are now exceedingly rare due to over fishing) but as early as the late 1700s they were transported northwards by

natives There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...

to provide a continuing food source. They prefer larger bodies of

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

with muddy bottoms, often seen basking on emerged rocks or floating logs. Most activity takes place between mid-March and October as well as the winter months by burying themselves into the mud.

Status

They are still consumed today in the remote areas of Baja by native people. Although they are extremely wary of humans being very difficult to approach and are high maintenance, they make good house pets.

References

;Bibliography * Trachemys Turtles of North America Endemic reptiles of Mexico Fauna of the Baja California Peninsula Natural history of Sinaloa Natural history of Sonora Reptiles described in 1895 Taxa named by John Van Denburgh {{Turtle-stub