FWS Focus

Overview

Characteristics
Overview

The flattened musk turtle is a small aquatic turtle only known to occur in the state of Alabama. It is estimated that it currently inhabits approximately 25 to 30 percent of its historic range in the upper Black Warrior river system. Siltation has been identified as the biggest threat to populations of flattened musk turtles. Habitat has also been lost to impoundments and development, as well as over-collecting for the pet trade is a threat to the species. 

Scientific Name

Sternotherus depressus
Common Name
Flattened Musk Turtle
FWS Category
Reptiles
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Optimum habitat of the flattened musk turtle appears to be free-flowing large creeks or small rivers with vegetated shallows about 2 feet (0.61 meters) deep alternating with pools 3.6 to 5 feet (1.1 to 1.52 meters) deep. These pools have a detectable current and an abundance of crevices and submerged rocks, overlapping flat rocks or accumulations of boulders. Habitats with high amounts of sand are also suitable as long as plenty of bedrock, boulder and cobble substrate exist with suitable food supply. In impounded systems, the turtle can be found in the headwaters and around the margins of lakes. Turtles in lake habitats often prefer areas along the bank that have an abundance of shelf like rocks. Other factors that indicate good habitat quality for this turtle include abundant snails and mussels, low silt load and deposits, low nutrient and bacterial counts, moderate temperature and minimal pollution.? 

River or Stream

A natural body of running water.

Characteristic category

Food

Characteristics
Food

The diet consists primarily of mollusks, including snails, mussels and clams, and aquatic insects. Adults appear to target and feed primarily on aquatic snails, clams, including the non-native Asiatic clams, and mussels. Juveniles, turtles that are less than 2.75 inches (6.99 centimeters), primarily prey upon softer-bodied aquatic insects.? 

Characteristic category

Behavior

Characteristics
Behavior

The turtle is active during the months of April to October. Adult flattened musk turtles are primarily nocturnal. While juveniles are more?likely than adults to be active during the day, they are also most active with darkness.?? 

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

The flattened musk turtle is a small aquatic turtle with a distinctly flattened carapace, or upper shell, up to 4.7 inches (11.93 cm) long.? 

Characteristic category

Life Cycle

Characteristics
Reproduction

Female flattened musk turtles reach sexual maturity at 6 to 8 years of age, while males require only four to six years to reach sexual maturity. Females lay two clutches of eggs per year, with clutch size ranging from one to three eggs. Ovulation occurs in May, for the first clutch, and in June, for the second clutch. Eggs in the first clutch are usually laid in May, while eggs in the second clutch are laid in the middle of June through early July. The incubation period is not known, although, one natural nest that contained two eggs took at least one and a half months to hatch. The nesting season is May through September. While very little is known about nesting preference of the flattened musk turtle, it is thought that they nest within 100 feet from the river bank in full to partial sun areas such as woodlands and roadsides.? 

Geography

Characteristics
Range

The flattened musk turtle is endemic to the upper Black Warrior River system in Alabama.???? 

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Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

7 Items

Listing

Listing

Listing

Listing

Listing

Five Year Review

Five Year Review

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Listing

Dec 30, 1982

Dec 30, 1982 Listing
Review of Vertebrate Wildlife for Listing as End. or Thr. Species
  • Publication type: CNOR
Item 1

Listing

Apr 5, 1984

Apr 5, 1984 Listing (Substantial)
Finding on Petition to List Flattended Musk Turtle; 49 FR 13558-13559
  • Publication type: 90 day petition finding
Item 2

Listing

Jul 18, 1985

Jul 18, 1985 Listing (Warranted But Precluded)
Findings on Petitions & Initiation of Status Review; 50 FR 29238
  • Publication type: 12m petition finding
Item 3

Listing

Nov 1, 1985

Nov 1, 1985 Listing (Threatened)
Proposed Thr. Status for Flattened Musk Turtle; 50 FR 45638-45643
  • Publication type: Proposed
Item 4

Listing

Jun 11, 1987

Jun 11, 1987 Listing (Threatened)
Determination of Thr. Status for Flattened Musk Turtle (Sternotherus depressus); 52 FR 224__?
  • Publication type: Final
Item 5

Five Year Review

Jul 6, 2009

Jul 6, 2009 Five Year Review (Information Solicitation)
Initiation of 5-Year Status Reviews of 23 Southeastern Species
  • Publication type: Notice
Item 6

Five Year Review

Jun 20, 2019

Jun 20, 2019 Five Year Review (Information Solicitation)
Initiation of 5-Year Status Reviews for 53 Southeastern Species; Notice of reviews; request for info…
  • Publication type: Notice
Item 7