The evolutionary trend of platform denticulation in Middle Triassic acuminate Gondolellidae (Conodonta)

Abstract

Acuminate Middle-Late Triassic Gondolellidae are characterized by an ellipsoid platform with a central to posterioramygdaloid basal cavity and an octomembrate apparatus of gondolelloid affinity. Starting with a neospathodiform proteromorph duringthe Anisian, their anagenetic lineage developed during the Fassanian, Longobardian, and Julian, ending in another neospathodiformproteromorph. As the increase in complexity in the platform denticulation is an important evolutionary trend, three new genera areproposed: Guexispathodus n. gen., Marquezella n. gen., and Kirilella n. gen., which, together with Pseudofurnishius and Mosherella,represent the subfamily Marquezellinae n. subfam.