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Species Name: 
Crepidula cf. plana Say, 1822

Common Name:
Eastern white slipper shell

Species Description:
Crepidula cf. plana is similar to Crepidula plana but has direct development as opposed to a short planktonic stage. The 2 species are similar in appearance, but C. cf. plana is significantly smaller at only 5 - 8 mm in length.  Shells are oval and flat in appearance, and white in color.  Both C. plana and C. cf. plana can be found inside empty shells of whelks and moon snails.  C. cf. plana is expected to be renamed.

Potentially Misidentified Species:
Species is very similar to Crepidula plana, the eastern white slippersnail.

II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
The northernmost extent of the range of Crepidula plana and its close relatives, including C. cf. plana, is eastern Canada.  C. plana ranges south to the Gulf of Mexico.  

IRL Distribution:
Crepidula cf. plana is found throughout the Indian River Lagoon.

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Males of Crepidula cf. plana are characteristically smaller than females. Minimum, typical and maximum sizes for males are: 1, 5 and 8 mm respectively; for females, these sizes are: 5, 10 and 16 mm.  Longevity for male C. cf. plana is typically 6 months but females can live for 2 years. However, the size and sex change of Crepidula cf. plana often depends on the social structure of a population as well as on environmental conditions.

Reproduction:
Crepidula cf. plana is a protandric hermaphrodite which is reproductively active year round. It has as many as 6 reproductive periods per year, producing from 100 to 200 young. Reproductive seasonality peaks during the summer for this species.

Embryology:
Eggs in Crepidula cf. plana are brooded. Typical larval development time is 21 days, but can range from 14 to 28 days.

IV.  PHYSICAL TOLERANCES

Temperature:
Crepidula cf. plana is considered eurythermic.  Temperature ranges, recorded from a data logger in the Indian River Lagoon show that C. cf. plana tolerates a temperature range between  5 - 35 °C.

Salinity:
Crepidula cf. plana is oligohaline to euryhaline.  Salinity ranges, recorded from a data logger in the Indian River Lagoon show that this species tolerates salinities between 15 - 38 ppt.  

Other Physical Tolerances: 
C. cf. plana prefers well oxygenated conditions.

V.  COMMUNITY ECOLOGY

Trophic Mode:
Juvenile and adult Crepidula cf. plana are suspension feeders.

Habitat:
Crepidula cf. plana prefers epibenthic habitats in oyster reefs. Crepidula cf. plana is located intertidally to subtidally with low wave exposure, preferring slow flowing water conditions.

VI. SPECIAL STATUS

Special Status:
None

Economic Importance:
None

Report by:  T. Griffin, Florida Institute of Technology
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Page last updated: July 25,  2001