Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Journal of Paleontology

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by SHIBATA, T. F. Articles by OJI, T. Search for Related Content GeoRef GeoRef Citation

KIIMETRA MIOCENICA, A NEW GENUS AND SPECIES OF THE FAMILY CALOMETRIDAE (ECHINODERMATA: CRINOIDEA) FROM THE MIDDLE MIOCENE OF SOUTHWESTERN JAPAN

¹ Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

The first 20% of the full text of this article appears below.

	INTRODUCTION

 
EXTANT COMATULID (stalkless) crinoids consist of approximately 530 species, classified in 143 genera and 18 families (Clark, 1931, 1941, 1947, 1950; Clark and Clark, 1967; Messing and White, 2001). Recent comatulids account for almost 85% of all the extant crinoid species (comatulids plus stalked crinoids), and their taxonomy is currently being extensively revised (e.g., Hoggett and Rowe, 1986; Rowe et al., 1986; Messing and White, 2001). In stark contrast to such a high extant diversity, records of fossil comatulids are far less common. This is partly due to their low fossilization potential. From the Cretaceous, only 18 genera and nine families of comatulids have been documented (Rasmussen, 1978).

The oldest record of a comatulid dates back to the late Triassic (Paracomatula Hess, 1951; Hagdorn and Campbell, 1993; Simms et al., 1993). Up to the late Cretaceous, the most diverse taxa were notocrinids and solanocrinids (Rasmussen, 1961; Jagt, 1999). The comatulids probably diversified during the Cenozoic (compare Jagt et al., 2002).

Cenozoic records of comatulids are thus very important for understanding comatulid diversification. In contrast to stalked crinoids, which occur only at depths below 100 m in modern seas, comatulids are the only crinoid group which flourishes in shallow-water settings. In order to understand the timing and pattern of comatulid survival and diversification, data on Cenozoic comatulids are crucial. Until now, most reports of fossil comatulids chiefly described centrodorsals, because other skeletal parts are easily disarticulated and lost after death (Meyer and Meyer, 1986).

In the current paper, we describe a very well-preserved new comatulid species from the Miocene of southwestern Japan, the first report of a fossil member of the Calometridae. It is named Kiimetra miocenica n. . . . [Full Text of this Article]