Evidence of congenital block vertebra in Pleistocene Cave Bear (Ursus spelaeus) from Cueva de Guantes (Palencia, Spain)

Abstract Objective This work provides a detailed description and differential diagnosis of a Pleistocene cave bear ( Ursus spelaeus ). Materials The specimen was recovered at the Cueva de Guantes archaeo- paleontological site, located in the North of the Iberian Peninsula and dated to more than 30k yr BP. Methods The study was carried out by macroscopic and radiological analysis. Results The specimen has unusual morphology, with two vertebrae (C6-C7) connected in the ventrodorsal projection by osseous tissue, without a space or disruption between them. However, a separation is visible in the dorsoventral projection. Moreover, C7 shows a “wedge-shape” conformation. Conclusions The lack of clear radiological and macroscopic evidence of degenerative processes and trauma suggests a congenital anomaly or pathology. The short height of the ventral margin of the block and evidence of a radiological ‘waist’ lead us to propose congenital block vertebra (CBV) as the most likely diagnosis. Significance The Cueva de Guantes specimen would be the first reported evidence of CBV in a Pleistocene cave bear ( Ursus spelaeus ). Limitations All diagnosis of archaeological animal remains should be undertaken with caution, especially when based on partial remains, as in this case. Moreover, this specimen lacks the neural arches of C6 and C7, preventing evaluation of the vertebral foramina. Suggestions for Further Research Intensive review of cave bear skeletal collections is advised to find new cases and perform an epidemiological approach to the palaeopathology of cave bears.