NovttatesAMERICAN MUSEUM PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET NEW YORK, N.Y. 10024 U.S.A. NUMBER 2579 MAY 29, 1975 HAROLD B. ROLLINS Gastropods from the Lower Mississippian Wassonville Limestone in Southeastern Iowa & AMERICAN MUSEUM Novitates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2579, pp. 1-35, figs. 1-11, tables 1-26 May 29, 1975 Gastropods from the Lower Mississippian Wassonville Limestone in Southeastern Iowa' HAROLD B. ROLLINS2 ABSTRACT A Lower Mississippian (Kinderhookian) gas- An unexpected aspect of the Wassonville gas- tropod fauna is described from the Wassonville tropod fauna is that it shows greater taxonomic Formation in southeastern Iowa. This represents affinity with the European Carboniferous than one of the few well-preserved Lower Mississip- with other North American Carboniferous pian gastropod faunas known from North faunas. This probably reflects the paucity of de- America and, as such, contributes to our under- scribed North American Mississippian gastropod standing of a rather critical time in the evolution faunas and the increased understanding, through of Paleozoic gastropods. recent study (notably Batten, 1966), of British Twenty-eight species are described, eight of and Belgium Tournaisian and Visean gastro- which are new. The new taxa are: Sinuitina nudi- pods. dorsa, Platyschisma laudoni, Trepospira (An- The genus Cerithiodes, long known from gyomphalus) penelenticulata, Baylea angulosa, the Upper Paleozoic of Europe, is recognized Glabrocingulum (Glabrocingulum) minutum, for the first time in the Carboniferous of North Glyptotomaria (Dictyotomaria) quasicapillaria, America. Cerithioides judiae, and Baylea trifibra. INTRODUCTION The Kinderhookian Wassonville Formation in cies, at least 10 are conspecific or closely related southeastern Iowa contains several weathered to European forms. chert zones that are very fossiliferous. The pres- Well-preserved gastropod faunas are rare in the ent paper is a taxonomic study of the prolific Mississippian of North America, hence an ade- gastropod fauna of the type Wassonville section quate understanding of the phylogenies of many near Daytonville, Iowa. gastropod taxa between the Lower and Upper Twenty-eight gastropod species are described, Paleozoic is lacking. I hope that the present eight of which are new. Many of the Wassonville study will contribute to our knowledge of this gastropods have distinct affinities with species critical period of gastropod evolution. from the European Carboniferous. Of the 28 spe- The pleurotomariaceans are the dominant gas- 'Scientific Contribution No. DEPS - 74-239. 2Research Associate, Department of Fossil and Living Invertebrates, the American Museum of Natural History; Associate Professor, Earth and Planetary Sciences, University of Pittsburgh. Copyright i The American Museum of Natural History 197N5ISSN 0003-0082 / Price $2.10 2 AMERICAN MUSEUM NOVITATES NO. 2579 tropods in the Wassonville chert zones but are TABLE 1 closely challenged, in abundance, by the bellero- Superfamily Analysis of Wassonville Gastropods phontaceans. Moreover, the Wassonville gastro- pod fauna is more diverse than most previously Superfamily Number of Species described from the Lower Mississippian. An anal- Pleurotomariacea 9 ysis, by superfamily, of the 28 described Wasson- Bellerophontacea 7 ville species is presented in table 1. Euomphalacea 1 The Wassonville gastropod fauna has never Platyceratacea 2 been described, although faunal lists were com- Microdomatacea 1 piled by Van Tuyl (1921, pp. 74-75) and Laudon Anomphalacea 1 (1931, pp. 380-382). Neritacea 1 Murchisoniacea 4 ACKNOWLEDGMENTS Loxonematacea 2 The present paper is adapted from a Master's thesis prepared in 1963 at the University of Wis- Van Tuyl (1921) and Laudon (1931). Laudon consin. I am grateful to Dr. Roger L. Batten of considered the Wassonville fauna to be late the American Museum of Natural History for his Kinderhookian and correlated the Wassonville help and guidance in the preparation of the origi- Formation with portions of the Chouteau of Mis- nal manuscript, and for his critical review of the souri. revised manuscript. Dr. Niles Eldredge, also of Straka (1968) concluded that the conodont the American Museum of Natural History, pro- fauna of the upper Prospect Hill and Wassonville vided many stimulating discussions regarding ele- formations resembled the Siphonodella iso- ments of this fauna. sticha-S. cooperi Assemblage Zone of Collinson, I thank Dr. Lowell Laudon of the University Scott, and Rexroad (1962) and thus correlated of Wisconsin for originally suggesting the study this interval with the uppermost cuIla zone in of the Wassonville gastropods and for making his Germany (Tournasian). extensive collections available to me. Nearly all the gastropods described in this Mr. Harrell L. Strimple of the State University study were collected from chert zones in the of Iowa very generously made available Wasson- Wassonville Formation at its type locality on the ville gastropod specimens from the Belanski col- south bank of the English River about 1 mile lection. north of Daytonville, Iowa, SW 1/4, SW 1/4, Mr. G. Robert Adlington of the American sect. 7, R. 8 W, T.77 N, Washington County, Museum of Natural History made the excellent Iowa (see fig. 1). At this locality, the Wassonville photographs for this paper. is a massive brown dolomite about 17 feet thick. Finally, but no less gratefully, my thanks to Four distinct chert zones are present and the Mrs. Judi Rollins for typing and editing the man- middle two zones contain the most abundant uscript. molluscan fossils. STRATIGRAPHY PREPARATION AND MEASUREMENTS In southeastern Iowa, the Kinderhookian is Generally, specimens were easily obtained represented by the McCraney Formation, the from the highly weathered chert nodules by care- Prospect Hill Formation, and the Wassonville ful use of a hydraulic rock trimmer. In order to Formation. An excellent historical summary of preserve delicate ornament patterns, many speci- the stratigraphic nomenclature and correlation of mens were coated with a solution of "Alvar" in these units can be found in Straka (1968). acetone. The Wassonville Formation, first named by All measurements were made with the aid of a Bain (1895) as the Wassonville Limestone of the micrometer eyepiece and a modified goniometer Maple Mill Formation, was studied in detail by attached to a microscope ocular. Specimens were 1975 ROLLINS: GASTROPODS 3 O miles 5 1ic w Collecting I Locality FIG. 1. Map showing collecting area for the chert zones of the Wassonville Limestone in south- eastern Iowa. measured with the axis of coiling nearly perpen- CBS, number of spiral cords below the selenizone dicular to the line of vision and, unless otherwise CS, distance from upper selenizone margin to noted, all measurements were taken on the last first major spiral element above selenizone or basal whorl. H, height HA, apertural height of exposed whorl (used in SYMBOLS AND ABBREVIATIONS MBW,measuringminimumbellerophontaceans)width The following institutional abbreviations are PA, pleural angle used in connection with specimen catalogue PD, diameter measured perpendicular to the height (used in measuring bellerophontaceans) numbers: SS, distance from suture to upper selenizone AMNH, the American Museum of Natural His- margin tory SW, width of selenizone SUI, the University of Iowa, Iowa City W, width WA, apertural width The following symbols are used in the mea- WH, height of basal whorl surements: WW, width of basal whorl CAS, number of spiral cords above the selenizone 4 AMERICAN MUSEUM NOVITATES NO. 2579 ..i 1, t'*. ,-ze ".. s Y;= ___- a 's;:X y-i F : .nw,* s : .- s i r i 'r' tt %, , -} =_., * > w. r # \t;:W .+: M A B w o.. -Z I.jmi ,, I~ , - -% i.. Ag D ,t H FIG. 2. A-C. Sinuitina nudidorsa, new species. A. Umbilical view, AMNH 29322. X5.0. B. Apertural view of holotype, AMNH 29322. x5.0. C. Umbilical view of paratype, AMNH 29323. x8.0. D-F. Euphemites sp. cf. E. urii (Fleming). D. Apertural view, AMNH 29324. X2.5. E. Umbilical view, AMNH 29324. x 2.5. F. Dorsal view, AMNH 29325, showing sinus. x 3.0. G, H. E. lentiformis (Weller). G. Dorsal view, AMNH 29326. x 7.0. H. Umbilical view, AMNH 29326. X 7.0. 1975 ROLLINS: GASTROPODS 5 SYSTEMATIC PALEONTOLOGY TABLE 2 Measurements (in Millimeters) of Sinuitina CLASS GASTROPODA nudidorsa Rollins, New Species ORDER ARCHAEOGASTROPODA MBW HA WA H PD SUPERFAMILY BELLEROPHONTACEA Holotype, AMNH 1.40 4.20 4.00 7.80 5.60 FAMILY SINUITIDAE DALL, 1913 29322 Paratype, AMNH - - - 5.00a - SUBFAMILY BUCANELLINAE KOKEN, 1925 29323 GENUS SINUITINA KNIGHT, 1945 SUI11203 1.60 3.80 3.60 7.60 5.20 Type Species. Tropidocyclus cordiformis aEstimated. Newell, 1935. that has been reported from the Mississippian of Sinuitina nudidorsa, new species ex- 2A-C Michigan, Ohio, Indiana, and Iowa. I have Figure amined the specimens described by Hyde (1953, Diagnosis. Sinuitina nudidorsa is readily dis- pl. 46, fig. 32) as Tropidodiscus cyrtolites (Hall) tinguished from all other Carboniferous species from the Byer sandstone of Ohio. These speci- of Sinuitina by its restricted lateral ornament. mens are much larger than S. nudidorsa, the col- Sinuitina brevilineatus (Conrad), a middle De- labral costae are uninterrupted on the lateral vonian species, appears closest to S. nudidorsa, whorl surface and faint spiral lira occur low on but possesses a lirate dorsal periphery. the lateral