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2015 Southeastern Naturalist Notes Vol. 14, No. 4
D.M. Frings and K.J. Morse
New State Record and Southeastern United States Range
Extension for Cyzicus mexicanus (Claus) (Mexican Clam Shrimp)
David M. Frings1,* and Kevin J. Morse2
Abstract - Cyzicus mexicanus (Mexican Clam Shrimp) is a small crustacean with a bivalve carapace.
It was previously known from freshwater vernal pools in 18 US states, 2 Canadian provinces, and
numerous Mexican states prior to our 2010 discovery in Shelby County, AL. This new state record
extends the range of the Mexican Clam Shrimp farther into the southeastern US than previously
documented.
Cyzicus mexicanus (Claus) (Mexican Clam Shrimp; Fig. 1) is placed in the family
Cyzidae, suborder Spinicaudata, although the taxonomy of the latter group has been
poorly studied and remains unresolved. The Mexican Clam Shrimp has not been recorded
1Department of Biological and Environmental Sciences, Samford University, Birmingham, AL 35229.
2Department of Biological and Environmental Sciences, University of West Alabama, Livingston, AL
35470. *Corresponding author - dmfrings@samford.edu.
Manuscript Editor: Lance Williams
Notes of the Southeastern Naturalist, Issue 14/4, 2015
Figure 1. Cyzicus mexicanus from the population discovered in Shelby County, AL.
2015 Southeastern Naturalist Notes Vol. 14, No. 4
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D.M. Frings and K.J. Morse
farther southeast than the states of Texas, Arkansas, Tennessee, and Virginia in the US
(NatureServe 2015). In 2010, the authors extended the species’ southeastern range with the
discovery of a single population in Shelby County, AL (Fig. 2). We discovered the population,
which numbered in the hundreds, during field studies at Oak Mountain State Park to
record the species of amphibians associated with vernal pools. The Mexican Clam Shrimp
had colonized a single vernal pool that formed in an unimproved service road. A specimen
from the new site is shown in Figure 1.
Populations of Mexican Clam Shrimp have been documented from most Mexican
states, the provinces of Alberta (Clifford 2013) and Manitoba in Canada, and 18 US
states (NatureServe 2015). Alabama is the 19th US state where the species has been documented.
As shown in Figure 2, the US populations of Mexican Clam Shrimp range from
the middle-Atlantic states in the east, west through Texas and the Southwest to Arizona
(Belk 1992) and California. Until this discovery, Mexican Clam Shrimp had not been recorded
from Alabama.
Acknowledgments. We thank D. Christopher Rogers, Kansas Biological Survey for his
independent taxonomic verification of our Mexican Clam Shrimp specimens. We also thank
Figure 2. Distribution of Cyzicus mexicanus in the United States modified from NatureServe (2015)
with additions from the collections of the National Museum of Natural History (Smithsonian Institution,
Washington, DC), the Yale Peabody Museum (New Haven, CT), Harvard University's Museum
of Comparative Zoology (Cambridge, MA), and field data by the au thors.
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2015 Southeastern Naturalist Notes Vol. 14, No. 4
D.M. Frings and K.J. Morse
Samford University, the Oak Mountain Interpretive Center, Oak Mountain State Park, and
the Alabama Department of Conservation and Natural Resources for their support of the
field work that led to the discovery and documentation of this n ew state record.
Literature Cited
Belk, D. 1992. Observations on the clam shrimps of Arizona in limnology and aquatic biology of the
southwest. Journal of the Arizona–Nevada Academy of Science 26(2):132–138.
Clifford, H.F. 2013. Aquatic invertebrates of Alberta. University of Alberta, Department of Biology.
Available online at http://sunsite.ualberta.ca/Projects/Aquatic_Invertebrates/?Page=47. Accessed
20 August 2013.
NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life, Version 7.1. Arlington, VA.
Available online at http://www.natureserve.org/explorer. Accessed 26 April 2015.