FIRST RECORD FROM NEBRASKA OF THE CLAM SHRIMP EULIMNADIA DIVERSA (CRUSTACEA: BRANCHIOPODA: CONCHOSTRACA).
During the summer of 1998, I collected larval amphibians across Nebraska as a means of testing for declines in historical populations. While collecting amphibians, particularly in ephemeral and seasonal pools, I commonly encountered representatives of the three orders of branchiopods (Conchostraca, Notostraca, and Anostraca). On 10 July 1998, I sampled a small Sandhills stock pond 12.8 km north of Halsey in Thomas County, Nebraska, for invertebrates and larval amphibians. The collection site measured 34 x 12 m (widest point) and had a maximum water depth of 15 cm. Water was clear and contained emergent vegetation. The mud substrate was undisturbed, suggesting no recent use by cattle. I acquired the location data using a hand-held Global Positioning System unit and county maps (SW 1/4 section 36, T24NR6W: N 42[degrees] 00.473', w 100[degrees] 16.048'). I obtained samples with a 25-cm diameter fine-mesh dip net and preserved them in 10% formalin. Denton Belk (Research Associate, Department of Invertebrate Zool ogy, Smithsonian Institution, Washington, D.C.) identified all my branchiopod specimens. Voucher specimens (NMNH# 243769) are at the National Museum of Natural History, Washington, D.C.
I collected Eulimnadia diversa, a conchostracan not previously recorded from Nebraska, from the site described above. Clam shrimps, of the order Conchostraca, are generally described as being encased in a bivalved carapace (Fig. 1) and possessing sessile, compound eyes, a laterally compressed body, and 10-28 pairs of legs (Fig. 2) (Belk 1982; Pennak 1989). The genus Eulimnadia belongs to the family Limnadiidae and is separated from other conchostracans by a frontal-organ character (Fig. 2) unique to this group (Belk 1982). Belk (1989) discussed the species-specific nature of the surface structure of resting eggs for Eulimnadia (Fig. 3).
I found Eulimnadia diversa with other common ephemeral aquatic inhabitants, such as insects of the orders Hemiptera and Coleoptera. The only vertebrate found was an Ornate Box Turtle (Terrapene ornata).
This project was funded in part by the United States Geological Survey's Biological Resources Division and the Lower Loup Natural Resource District. Denton Belk graciously identified all the large branchiopod specimens from my field work and provided guidance and technical information during the preparation of this work. John D. Lynch encouraged me to look for the fascinating creatures while I collected tadpoles.
Belk, D. 1982. Synopsis and Classification of Living Organisms: Branchiopoda, pp.174-180. New York, McGraw-Hill Book Co.
-----. 1989. Identification of species in the conchostracan genus Eulimnadia by egg shell morphology. Journal of Crustacean Biology 9 (1): 115-125.
Pennak, R.W. 1989. Fresh-water Invertebrates of the United States. Protozoa to Mollusca, 3rd ed., pp. 362-365. New York, John Wiley and Sons, Inc.
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|Author:||McLeod, David S.|
|Publication:||Transactions of the Nebraska Academy of Sciences|
|Article Type:||Brief Article|
|Date:||Jun 1, 2000|
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