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Praedictyorbitolinid

phyletic lineage

by R. Schroeder, B. Clavel, A. Cherchi, and J. Charollais.

The representatives of the orbitolinid genera Praedictyorbitolina SCHROEDER, CLAVEL et CHAROLLAIS and Dictyorbitolina  CHERCHI et SCHROEDER belong to a monophyletic lineage ranging from the Late Hauterivian to the Earliest Barremian. The establishment of this lineage is based on three evolutionary trends:

  • increase of the size of the tests and change of their morphology,

  • shift of the embryo and development of a subepidermic cellular layer within the deuteroconch,

  • evolution of the network of septula within the marginal zone.

SCHROEDER, R., B. CLAVEL, A. CHERCHI & J. CHAROLLAIS (1999).- Praedictyorbitolina busnardoi n.sp. (Foraminiferida) et évolution de la lignée Praedictyorbitolina - Dictyorbitolina (Hauterivien supérieur - Barrémien basal). Paläontologische Zeitschrift, Stuttgart, 73 (3/4), p. 203-215.

 

Dictyorbitolina ichnusae
Praedictyorbitolina carthusiana
Praedictyorbitolina claveli
Praedictyorbitolina claveli
Praedictyorbitolina busnardoi

Photos by courtesy of R. Schroeder et alii; sequences from CLAVEL et alii (1995), modified; Hauterivian ammonite zones from HOEDEMAKER, COMPANY et alii (1993); Barremian ammonite zones from VERMEULEN (1998); drawing B. Granier