RESUMO
Using a computerised technique that estimates differences or changes in the pattern defined by the distribution of 24 pore-canals of left valves of Paleocosta pervinquieri (Ostracode), we can speculate about the phylogenic evolution of the species ranging in age from Danian (66 My) to Ypresian (54 My) from the Djebel-Dyr section (North East of Algeria). This method is combined with traditional biometric and statistical studies and the analysis of architectural patterns of shells. Firstly, it reveals that Paleocosta pervinquieri is individualised in 6 morphs which evolve from the 'libyaenisis morph' to the 'mokkatamensis morph', between the P1 zone (66 My) to the P4 zone (56 My). During the P5 zone (55 My), we suggest that there has been a genation between the Paleocosta pervinquieri 'mokkatamensis morph' and the Reymensticosta sp. 'semi-reticulated morph'. Furthermore, the Theta-Rho method could be adapted and used for numerous paleontological and biological studies.
