BERRIOCHLOA GABELI AND BERRIOCHLOA HULETTI (GRAMINEAE: STIPEAE), TWO NEW GRASS SPECIES FROM THE LATE MIOCENE ASH HOLLOW FORMATION OF NEBRASKA AND KANSAS

Journal of Paleontology, Jan 2005 by Thomasson, Joseph R

All specimens are deposited in the FHSM paleobotanical collections. Because JRT accession numbers for individual specimens (e.g., SEM BP 625) or collections of specimens (e.g., 50.47) were frequently associated with field notes, logbooks, photographs, or specimen labels, those numbers are retained but equivalent FHSM specimen numbers are provided and added to specimen labels. The size and fragile nature of the prepared scanning electron microscopy specimens precludes etching FHSM numbers directly to the specimen preparations where the JRT numbers are already etched, but have been recorded in JRT's SEM specimen accession books. The FHSM accession numbers are designated in a PB (paleobotany) series, and are provided at the first appearance of the equivalent JRT accession number in the text. Thus, JRT SEM BP 625 is also FHSM PB 2017 and JRT 50.47 is also FHSM PB 2018.

Both light and scanning electron microscopy studies were made of the two new taxa, but only light microscopy was conducted on the Elias lectotype and isolectotype specimens of Ii. intermedia Elias, 1942. Specimens for SEM were mounted on round, brass discs (plates) with silver cement, coated with 60 percent Au/40 percent Pd, and examined in an ISl SX-30 scanning electron microscope and photographed on Polaroid 665 P/N film. Specimen designations, for example, 366 (=J. R. Thomasson Scanning Electron Microscopy Brass Plate specimen 366), were etched on discs with a vibrating scriber. SEM micrographs were then digitally scanned using a Microtek 4900 flatbed scanner and images and plates were prepared in CorelPaint 10 and CorelDraw 10, respectively. For taking measurements and light microscopy, specimens were temporarily positioned on blue Elmer's Tac 'N Stik. Fossils were initially photographed in color using a Nikon 995 digital camera in macro mode at a fine JPEG setting. For plate preparation of light microscopy images, CorelPaint was used to remove blue backgrounds around the fossil images with the magic wand tool and also to desaturate the color images. Final plates were prepared in CorelDraw 10 and saved as .cdr files.

Fossils were measured under a dissecting scope using a calibrated ocular micrometer. Terminology for measurements and description of features of the anthoecia follows Elias (1942), ElHs (1979), and Thomasson (1979a). Prickle hairs, as defined by ElHs (1979), is retained over tubercles of Elias (1942) and bulbousbased apical lemma hairs of Jacobs et al. (1995), and crown is used as originally defined by Elias (1942).

SYSTEMATIC PALEONTOLOGY

Division MAGNOLIOPHYTA

Cronquist, Takhtajan, and Zimmerman, 1966

Class LILIOPSIDA (MONOCOTS)

Cronquist, Takhtajan, and Zimmerman 1966

Order CYPERALES Burnett, 1835

Family GRAMINEAE de Jussieu, 1789

Genus BERRIOCHLOA Elias, 1932

BERRIOCHLOA GABELI new species

Figures 3.1-3.8, 4.1, 4.2, 7.1, 7.2, right specimen in 8.1-8.4

Diagnosis.-Berriochloa with relatively slender, ellipsoid to oblong anthoecia; well-developed crown and callus; hooks on lemma poorly developed to well developed but then restricted to shoulder and neck.