Moderately sized (approximately 3.5 m in length), short-necked plesiosaur possessing the following suite of characters: pineal foramen present (absent in Dolichorhynchops and Trinacromerum); fenestra ovalis present (absent in Dolichorhynchops); suspensorium vertically oriented (angled posteriorly in Plesiopleurodon and Dolichorhynchops); six to seven premaxillary teeth (commonly five to six in Dolichorhynchops, five in Trinacromerum bonneri); caniniform teeth present (absent in Dolichorhynchops and Trinacromerum); relatively short mandibular symphysis bearing six pairs of dentary teeth (eight in Plesiopleurodon. 18-20 in Dolichorhynchops); 26 cervical vertebrae (19 in Dolichorhynchops, 20 in Trinacromerum); forelimb phalangeal formula. 7-11-10-9-9.