Taxonomic revision of the genus Carinolithus (Early - Middle Jurassic) based on morphometric analyses and diagenesis observations: Implications for biostratigraphy and evolutionary trends

We applied morphometric analyses performed with a polarizing light microscope on total of 100 specimens Carinolithus superbus and C. magharensis to clarify the taxonomy based measurements height (TH), stem (SH), width (SW), proximal shield (PS), distal (DS) thickness (TDS). Statistical showed that three these parameters, namely DS, TDS SW, are diagnostic for taxa discrimination. New include subsp. crassus nov. minor Specimens cantaluppii were qualitatively investigated assess potential role secondary modifications our results revealed that, indeed, is diagenetic artefact due different degrees overgrowth poulnabronei, crassus, superbus, magharensis. This implies not true taxon, phase an effective proxy degree. The morphometry-based revised genus was improve biostratigraphic resolution Toarcian-Aalenian interval, further implications reconstruction evolutionary trends.