Taphonomy, osteology and functional morphology of a partially articulated skeleton of an archaic Pliocene right whale from Emilia Romagna (NW Italy)

A partial skeleton of a Pliocene balaenid whale (Mammalia, Cetacea, Mysticeti) is described and compared to a large setof extant and fossil Balaenidae. The specimen (MCRE 232834) includes a jugal, both mandibular rami and part of the postcranial skeletonincluding several vertebrae, complete ribs, hyoid, pelvis, a single scapula and a single partial forelimb. The specimen was found at a site in the vicinity of the San Valentino Castle, about 16 km S from Reggio Emilia, close to the town of Castellarano, Emilia Romagna (northernItaly). Molluscs and foraminifers indicate a late Zanclean age for MCRE 232834, constrained between 3.8 and 3.6 Ma. A taphonomic analysisrevealed that after death the individual sunk on the sea floor upside down and underwent a series of biostratinomic processes eventuallyleading to the collapse of the ribcage and to the disarticulation of the posterior thoracic, lumbar and caudal vertebrae, together with theloss of several skeletal elements including the skull. Shark teeth and encrusting molluscs demonstrate that the specimen was exploited bydifferent organisms during its decay. The study of the skeleton revealed that MCRE 232834 shows an abruptly converging anterior ends ofthe mandibular rami, well-developed olecranon process in the ulna, peculiar morphology of the cervical vertebrae and enlarged attachmentsites for axial muscles in the ribs. Based on the morphology of the cervical vertebrae, mandible and scapula, MCRE 232834 can be assignedto a new genus and species of the family Balaenidae, i.e., Charadrobalaena valentinae n. gen., n. sp., which is part of a primitive clade ofbalaenids that is the sister group of the crown balaenid whales. A functional analysis of the vertebral column revealed that it was able ofcomparatively faster and more agile swimming with respect to the extant balaenid species .