Middle Jurassic record of the limnic ostracode genus &amp;lt;i&amp;gt;Rosacythere&amp;lt;/i&amp;gt; (Limnocytheridae, Timiriaseviinae): implications on the origin and evolution of the &amp;lt;i&amp;gt;Kovalevskiella&amp;lt;/i&amp;gt; group

J.-P Colin,P Carbonel

doi:10.1144/jm.15.2.187

Abstract

Abstract. Two species of the limnic ostracode genus Rosacythere Colin (Limnocytheridae, Timiriaseviinae) have been identified in the uppermost Bajocian (Middle Jurassic) of the southern part of the Paris Basin, France. This record is the earliest for this genus and for the ‘Kovalevskiella group’ of Colin &amp; Danielopol (1978 Colin &amp; Danielopol (1980). This study also confirms that most of the Timiriaseviinae morphological groups really started to diversify during the Middle Jurassic.

Highlights

INTRODUCTIONThe limnic ostracod genus Rosucyrhere, defined by Colin (in Colin & Danielopol, 1980), belongs to the family Limnocytheridae, subfamily Timiriaseviinae
The limnic ostracod genus Rosucyrhere, defined by Colin, belongs to the family Limnocytheridae, subfamily Timiriaseviinae
Zhao (1987) considered the genus Rhrorocyi‘here as a ‘Tertiary derivative’ of Rosucythere, which differs from other genera of the Kovalrv.skiella lineage by its normal hinge with positive elements on the right valve and its less regular type of ornamentation

Summary

INTRODUCTION

The limnic ostracod genus Rosucyrhere, defined by Colin (in Colin & Danielopol, 1980), belongs to the family Limnocytheridae, subfamily Timiriaseviinae. The genus Kosucythere was considered to be restricted to the Late Aptian to Cenomanian interval (Fig. 1 ) of southern Europe, being known especially from SW France, Spain. The genus Framhocythere, originally thought to be restricted to the Late Maastrichtian to Early Eocene interval from southern Europe (southern Belgium, France and Spain), India and China, has recently been identified in the Albian of Zaire (Colin, 1993). THE GENUS ROSACYTHERE IN THE MIDDLE JURASSIC it is currently accepted that the first Timiriaseviinae probably appeared during the Triassic (Colin & Danielopol, 1980), they really started to develop and to diversify only during the Middle Jurassic and especially during the Bathonian as indicated by the presence of numerous species of the genera Timirimevia Mandelstam, 1947, and Theriosynoecum Branson, 1936 (Whatley, 1990: Colin, in press).

Cenomanian Albian Aptian

Ostracocle genus Rosacythere

CONCLUSIONS