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75 More than 30 species of fossil mollusks occur in the deposits (Substratum B3 per C. V. Haynes, chapter 3, this volume) associated with the bones of butchered mammoths at the Lange/Ferguson site in Oglala Lakota County, South Dakota. About two-thirds of the molluscan species are terrestrial pulmonates that lived in the wooded, shrubby, or grassy slopes surrounding the marshy lake in which the mammoths appear to have foundered; far denser populations of aquatic species lived in the waters of the shallow lake or along its moist shores. During analysis , matrix containing both kinds of shells was washed over 500 µm mesh and the dried residue was searched for shells; screening was also conducted to search for bones and teeth of small vertebrates. Dense populations of freshwater mollusks are dominated by species of Lymnaea, of which L. palustris is most conspicuous, followed by species of Promenetus, Gyraulus, Aplexa, and Helisoma. For some reason, Physa, for which the local environment seems suitable, is wanting from the fauna. The only branchiate mollusks are two species of Pisidium, small pelecypods. The terrestrial elements of the molluscan fauna may be appropriately divided into three categories: (1) those requiring very moist situations; (2) those limited to woodlands or gallery forests; and (3) those with a wide tolerance of local environmental conditions . In the first category belong Succinea pleistocenica and Oxyloma retusa, always found in wet situations near water, and probably Vertigo hibbardi, formerly known only from the Pliocene of southwestern Kansas. The second category includes Cionella lubrica, Discus cronkhitei, Nesovitrea electrina, and two species of Vallonia. The remaining terrestrial gastropods, including the genera Columella, Gastrocopta, Euconulus, Hawaiia, Pupilla, and Vertigo, generally do not require forest cover but may utilize it. An analysis of the molluscan fauna at the Lange/ Ferguson site presents a picture of a shallow, marsh-like lake with well-vegetated surroundings, including at least patches of woodland and brushy border slopes, and some open savanna vegetated by grasses and nonwoody herbs. The climate was obviously more humid than the conditions that now prevail at the site, but it seems not to have been significantly cooler than at present. Annotated List of Species in the Lange/Ferguson Fauna An annotated list of molluscan species in the Lange/ Ferguson fauna follows (figs. 40 and 41); pertinent items of significant literature for each taxon discovered, together with a short paragraph of general information about each member of the fauna, are provided. Aquatic Pulmonate Gastropods Lymnaea (Stagnicola) palustris Müller 1774 (see fig. 40, specimen 8) Buccinum palustre Müller 1774. Verm. Terr., vol. 2, p. 131. Galba palustris (Müller) Baker 1911. Lymnaeidae of North and Middle America, p. 298, pl. 26, figs. 17–37. Lymnaea palustris (Müller) Leonard 1950. Univ. Kansas Paleo Contrib., art. 3, Mollusca, p. 15, pl. 2, fig. F. Lymnaea palustris (Müller) Leonard and Frye 1975. Pliocene and Pleistocene Deposits and Molluscan Faunas, East-Central New Mexico, New Mexico Bur. Mines and Mineral Resources, Memoir 30, p. 24, pl. 1, fig. 10. Lymnaea palustris is a circumboreal aquatic gastropod, distributed in North America from Canada south to the Sand Hills lakes in Nebraska, and as a fossil as far south as Fort Sumner in New Mexico. L. palustris lives in water, but small pools will suffice, although unlike many other lymnaeids, it requires open water. The shell is an elongate spiral, ranging in length to 40 mm; the largest shells Ecological and Climatic Implications of Fossil Mollusks at the Lange/Ferguson Mammoth Site chapter five A. Byron Leonard 76 Chapter Five at the Lange/Ferguson site are little more than half this extreme. Lymnaea (Fossaria) dalli Baker 1906 (see fig. 40, specimen 11) Lymnaea dalli Baker 1906. Illinois State Lab. Nat. Hist., vol. 7, p. 104. Lymnaea dalli Baker, Leonard and Frye 1975. Pliocene and Pleistocene Deposits and Molluscan Faunas, East-Central New Mexico, New Mexico Bur. Mines and Mineral Resources, Memoir 30, p. 24. This smallest of the lymnaeids—the shell is seldom more than 6 mm in length—occurs from the Ohio Valley and Michigan to Arizona. Like L. parva, L. dalli often wanders from open water (Leonard 1952:22) but remains in damp situations. It frequently lives in ephemeral bodies of water, surviving dry periods with no apparent difficulty. L. dalli occurs in the Lange/Ferguson site in moderate populations, and it is widespread as a Pleistocene fossil. Lymnaea (Fossaria) humilis Say 1822 (see fig. 40, specimen 9) Lymnaeus humilis Say 1822. Jour. Acad...

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Additional Information

ISBN
9781623495930
Related ISBN
9781623495923
MARC Record
OCLC
1031090235
Pages
262
Launched on MUSE
2018-04-16
Language
English
Open Access
No
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