Phylogenetic Relationships

Additional preparation of the holotype of Con-cornis lacustris from the Lower Cretaceous (Bar-remian) deposits of Las Hoyas (Spain) has pro-vided abundant new osteological data. This spec-imen is superbly preserved and anatomical details are available for most skeletal regions except the skull and neck. The forelimb has "modem " pro-portions but it retains large claws. The sternum is carinate and deeply notched. The carina, however, does not reach the cranial margin but is developed in the caudal halfofthe sternum. The dorsal, syn-sacral and caudal vertebrae are amphicoelous. The dorsal vertebrae have deep lateral grooves and parapophyses in a central position. The ischium has large obturator and dorsal processes; the pubes form a distal symphysis. The hind limb is gracile, elongate, and longer than the forelimb. Cladistic analysis of various ornithothoracine taxa supports the allocation of Concornis lacustris within the Enantiornithes, a major clade of Cre-taceous birds mostly recognized from continental deposits. This new interpretation is substantially supported by 12 synapomorphies shared by C. lacustris and the remaining enantiornithines