Bacteria and Protists from Kansas

PaleoBios, Volume 17, Number 1, Pages 20-26, July 13, 1996

Bacteria and protists from Middle Cretaceous amber of Ellsworth County, Kansas

Benjamin M. Waggoner

Department of Integrative Biology, University of California, Berkeley, CA 94720

ABSTRACT

Microfossils of sheathed bacteria and amoebae are reported from the middle Cretaceous amber of Ellsworth County, Kansas. The sheathed bacteria are morphologically very close to the living genus Leptothrix. Testate amoebae resemble the modern genera Pontigulasia and Nebela; these are the oldest fossil representatives of these genera. Other microfossils represent unicellular protists of some sort but cannot be identified further. This microfossil assemblage, similar to that in late Triassic amber from Bavaria, probably indicates an aquatic, oligo-mesosaprobic paleomicrohabitat. It also provides direct confirmation of morphological stasis in the amoeban taxa, which has been previously inferred from comparative molecular sequencing and biogeographical distribution.

INTRODUCTION

Amber has been known from Cretaceous strata in Ellsworth County, Kansas, since the mid-1930's (Buddhue, 1938). First named kansasite, it is now referred to as jelinite, after one of its discoverers, George Jelinek. As it is neither obviously fossiliferous nor suitable for jewelry, it has received very little attention from mineralogists and paleontologists. This situation is not helped by the fact that jelinite's only known locality is now covered by the Kanopolis Reservoir (Langenheim et al., 1965). Study of this amber is thus restricted to material collected before the construction of the Kanopolis Dam around 1948. It is usually opaque and brittle, it is rare in collections, and it contains no obvious macrofossils. Apparently no research has been done on it since 1965 (Langenheim et al., 1965).

Even amber that appears unfossiliferous, however, may contain a wide variety of microfossils. Examination of small fragments of jelinite show it to be rich in microscopic inclusions; many are not fossils or unidentifiable, but some are identifiable as fossils. These include assorted spores and pollen (personal observations) and cysts of an amoeboflagellate referable to the modern genus Naegleria, the first such cysts known as fossils (Waggoner, 1993). This paper describes sheathed filamentous bacteria and probable testate amoebae from jelinite, as well as unicellular organisms of uncertain affinity.

MATERIALS AND METHODS

The only locality where jelinite has ever been found was on the south shore of the Smoky Hill

Figure 1. Original locality of jelinite, Ellsworth County, Kansas.

River, Ellsworth County, Kansas, NW 1/4 SW 1/4 sec. 18, T.16 S, R.6 W (UCMP loc. D-797), now covered by a landslide and the Kanopolis Reservoir (fig. 1). The precise stratigraphic position cannot now be measured, but the surface rocks in this part of Kansas are Cretaceous. The amber was recorded as coming from a clay layer bounded by lignite. By comparison with extant stratigraphic sections in the area and with maps made before the reservoir was built, the amber probably came from the Kiowa Shale (Albian, Early Cretaceous) but possibly from the Terra Cotta Clay of the Dakota Group (Cenomanian, Late Cretaceous) (Langenheim et al., 1965). Jelinite is yellow to dark brown, sometimes thinly banded, opaque and often "fatty" in color and texture, and quite brittle.

Almost all Cretaceous amber is of coniferous origin (Langenheim, 1968), and both the Kiowa