TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE 103(1-2), 2000, pp. 76-94 Horseshoe Crabs (Arthropoda: Xiphosurida) from the Pennsylvanian of Kansas and Elsewhere LOREN E. BABCOCK Department of Geological Sciences, The Ohio State University, Columbus, Ohio 43210 DANIEL F. MERRIAM Kansas Geological Survey, The University of Kansas, Lawrence, Kansas 66047 Pennsylvanian strata of Kansas have yielded two species of xiphosurids (horseshoe crabs). The exceptionally preserved fossils are from inferred coastal (estuarine or tidal flat) paleoenvironments. One species, the euproop- id Euproops danae (Meek and Worthen), occurs in the Lawrence Formation (Upper Pennsylvanian: Virgilian) in Douglas County, Kansas. Siderite con­ cretions in the Lawrence Formation preserve organisms similar to those from Braidwood-type assemblages of the Mazon Creek biota of Illinois. This oc­ currence of E. danae in the Virgilian Stage (North American usage) is one of the few stratigraphically above the Desmoinesian Stage of North America or the Westphalian D Series of Europe. Another xiphosurid, the limuline Paleolimulus signatus (Beecher), occurs in the Pony Creek Shale Member of the Wood Siding Formation (Upper Pennsylvanian: Virgilian) in Wabaunsee County, Kansas. This occurrence extends the known stratigraphic range of P. signatus downward from the Permian into the Pennsylvanian. Another specimen that is here referred to P. signatus, and which was collected from the Mazon Creek biota of Illinois, shows that the species ranges downward to the Desmoinesian Stage (of North American usage). INTRODUCTION Xiphosurids or horseshoe crabs are an important, although generally un­ common, component of Pennsylvanian and Permian strata of Kansas. As a measure of their importance among xiphosurids generally, approximately 45 genera of Phanerozoic horseshoe crabs have been described (not all of which are valid), of which six genera were described using specimens from the Lower Permian of Kansas. This figure is mitigated, however, by the fact that five genera of putative xiphosurids that were described from the insect beds in the Lower Permian Wellington Formation of Elmo or Annelly, Kansas VOLUME 103, NUMBERS 1-2 77 (Tasch, 1961, 1963, 1964), have been reassigned subsequently to other ar­ thropod groups (Bergstrom, 1975). Another three genera have been reported from Pennsylvanian or Permian rocks of the state (Dunbar, 1923; Tasch, 1961, 1963, 1964; Bennett, 1984; Babcock, Merriam, and West, in press) after having been described using specimens collected elsewhere. It is note­ worthy that the genus Paleolimulus, which was described first from the Permian of Kansas (Dunbar, 1923), is a valid xiphosurid and represents one of the oldest known limulines, or so-called modern horseshoe crabs (Selden and Siveter, 1987; Anderson and Selden, 1997). The purpose of this paper is to document the Pennsylvanian horseshoe crabs that occur in Kansas. This work provides further information on the biogeographic and paleoenvironmental distribution of the taxa now known from the state, provides new information on their temporal distribution, and provides data relevant for a deeper understanding of the exceptional pres­ ervation of nonmineralized arthropod cuticle. Two xiphosurid species pres­ ently are known from the Pennsylvanian of Kansas: Euproops danae (Meek and Worthen) and Paleolimulus signatus (Beecher). Paleolimulus signatus, which also occurs in the Permian, is described more fully, primarily from Permian remains, by Babcock, Merriam, and West (in press). Previously, this species was documented from Kansas alone, but evidence presented here shows that the species distribution extended to Illinois. Euproops danae has not been documented from Kansas or adjoining states until now, although it has a wide distribution in Pennsylvanian strata of North America and Upper Carboniferous strata of Europe. This work shows that both E. danae and P. signatus range upward from the Desmoinesian Stage of North Amer­ ica; E danae extends into the Virgilian, and P. signatus extends into the Lower Permian. REPOSITORIES Specimens cited here are deposited in the following collections: Orton Geological Museum, The Ohio State University, Columbus, Ohio (OSU); Peabody Museum of Natural History, Yale University, New Haven, Con­ necticut (YPM); University of Kansas Natural History Museum (Division of Invertebrate Paleontology), Lawrence, Kansas (KUMIP); and U.S. Na­ tional Museum of Natural History, Smithsonian Institution, Washington, D.C. (USNM). LOCALITY AND STRATIGRAPHIC INFORMATION Pennsylvanian horseshoe crabs are reported here from two localities in Kansas (Fig. 1). Locality 1 has yielded only one specimen that we have examined, whereas locality 2 has yielded tens of specimens. A generalized stratigraphic section, showing locality intervals, is given in Figure 2. Ad­ ditional stratigraphic information concerning the units in which specimens 78 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE 102°W 40°N" KANSAS Locality 2 V Locality 1 100 km Figure 1. Map of Kansas showing localities yielding Pennsylvanian xiphosurans. Locality 1, near Lawrence, Douglas County (Lawrence Formation Konservat-Lagerstatte). Locality 2. near Maple Hill, Wabaunsee County (Pony Creek Shale Konservat-Lagerstatte). occur was provided by Jewett, O'Connor, and Zeller (1968). Productive beds for nonmineralized fossils such as those described in this paper are often referred to by the German term "Konservat-Lagerstatten" (following Sei­ lacher, 1970), which translates into English as "fossil conservation deposits" (Shields, 1998). Locality 1. Lawrence Formation Konservat-Lagerstatte. Lawrence Forma­ tion (Douglas Group; Upper Pennsylvanian: Virgilian), near Lawrence, Douglas County, Kansas. We have examined a single specimen of Euproops danae (YPM 35153) from the Lawrence Formation Lagerstatte. According to a specimen label written by W.H. Twenhofel, who probably acquired the specimen for the Yale Peabody Museum, the illustrated specimen (Fig. 3) is from "Train[?] mounds," "Lawrence? Shales," "near Lawrence, Kansas." The specimen is preserved as part and counterpart in a siderite concretion and, on the back of the counterpart, someone (presumably the collector) carved the words "Oct. 12th 1884 I dug this f[rom] the coal." Based on our experience with upper Paleozoic strata of eastern Kansas, the specimen probably was col­ lected from siderite concretions that occur in the shale immediately above the Williamsburg coal bed (see Moore and others, 1951; Jewett, O'Connor, and Zeller, 1968; Feldman and others, 1993; Fig. 4), near the top of the Lawrence Formation. The available locality data are insufficient to judge precisely where the specimen was collected although today there are only two reasonably good exposures of the Williamsburg coal bed in the vicinity of Lawrence. At both VOLUME 103. NUMBERS 1-2 79 UJ Q_ a: D JANESVILLE SHALE I o FALLS CITY LIMESTONE 5 DC ONAGA SHALE BROWNVILLE LS. < o MEMBER WOOD SIDING PONY CREEK FORMATION Locality 2 SHALE MEMBER D. ROOT SHALE \ => GRAYHORSE LS. O STOTLER LIMESTONE MEMBER or PILLSBURY SHALE PLUMB SHALE o MEMBER UJ ZEANDALE LIMESTONE LU WILLARD SHALE NEBRASKA CITY CO EMPORIA LIMESTONE LS. MEMBER z AUBURN SHALE < BERN LIMESTONE z C<D < SCRANTON SHALE z UJ < CD HOWARD LIMESTONE > < _J r- SEVERY SHALE >- 0) CO z TOPEKA LIMESTONE z < z _l D_ UJ CALHOUN SHALE oZ) a. o rr DEER CREEK CL O LIMESTONE uj > UJ TECUMSEH SHALE Q. UJ D. 3 z LECOMPTON < LIMESTONE I KANWAKA SHALE CO OREAD LIMESTONE -Locality 1 AMAZONIA LS. MEMBER 00 LAWRENCE < 0- FORMATION IRELAND SS. _J Z) MEMBER o o ROBBINS SHALE 3 rr MEMBER O es STRANGER HASKELL LS. o FORMATION MEMBER Figure 2. Generalized stratigraphic relationships of Upper Pennsylvanian (Virgilian) strata in Kansas and horizons yielding xiphosurans. Approximate positions ol" fossil conservation deposits discussed in text, keyed to Figure I, arc indicated. Upper part of Lawrence Formation, which contains locality I, is not divided into members (following the usage of Zeller. I968). Abbreviations: Ls., Limestone: Ss., Sandstone. 80 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE 1CT5«Kx .t, fmmk Figure 3. Euproops danae (Meek and Worthen, 1865), large specimen preserved in siderite concretion from the Lawrence Formation (Upper Pennsylvanian), near Lawrence, Kansas (lo­ cality 1 in Figs. 1, 2); YPM 35153, X 1. A, Counterpart, dorsal view, showing proximal part of telson. B, Part of same specimen, dorsal view, showing strong wrinkling and slight forward inclination of prosoma. siderite concretions Williamsburg coal bed Figure 4. Generalized stratigraphic section of the Lawrence Formation and parts of adjacent formations in Pennsylvanian Douglas Group of northeastern Kansas (modified from Zeller, 1968). Positions of Williamsburg coal bed and overlying siderite concretion-bearing shales of Lawrence Formation are indicated to right of stratigraphic column. Lithologic symbols are: dots, sandstone; dashed horizontal lines, shale: continuous horizontal lines, black shale; blocks, limestone; solid black, coal; cross hatches, red color. Thickness of Lawrence Formation in northeastern Kansas ranges upward to about 45 meters. VOLUME 103, NUMBERS 1-2 QUADRANGLE LOCATION Contour interval 50 feet. Figure 5. Map of localities in Douglas County, Kansas, showing exposures of Lawrence Formation from which specimen of Euproops danae (Fig. 3) may have been collected. Base map is from Lawrence, Kansas, 30' quadrangle topographic map (U.S. Geological Survey, 1889). Features such as Union