Article: Charophytes from the Lower Cretaceous of the Iberian Ranges (Spain)
Carles Martín-Closas and Carmen Diéguez
In the Upper Barremian of the Iberian Ranges (Las Hoyas, Cuenca, Spain) an association of exceptionally well preserved charophyte thalli comprises four new form-species: Palaeonitella vermicularis sp. nov., Charaxis spicatus sp. nov., Clavatoraxis robustus gen. et sp. nov., and Clavatoraxis diaz-romerali sp. nov. This is the youngest fossil record of the genus Palaeonitella. The new form-genus Clavatoraxis is erected to include charophyte vegetative remains bearing spine-cell rosettes, a character attributed to the family Clavatoraceae. This is the first time an assemblage of charophyte vegetative remains has been described and related to assemblages of fructifications. This gives a good correlation at family level between the frequency of taxa found as vegetative remains and calcified fructifications. Two biocoenoses are represented: Clavatoraxis robustus displays adaptations found in extant charophytes living in permanent shallow water lakes whereas Clavatoraxis diaz-romerali was adapted to light-limited, probably deeper, environments. Palaeonitella vermicularis grew twisted round thalli of Clavatoraxis. Early Cretaceous freshwater communities appear to have been dominated by charophytes, and not by aquatic ferns as believed previously.