An injured lion from Kanegra (Slovenia): CT evidence of survival after severe juvenile forelimb trauma in a MIS6 Eurasian lion

Traumatic limb injuries can be lethal for large predators, yet well documented fossil cases showing severe postcranial trauma with demonstrable long-term survival are extremely rare in extinct lions. We report a pathologically remodelled right humerus (MGGC 22655) from the Kanegra sinkhole (Istria, northern Adriatic), providing the first evidence of a juvenile cave lion surviving a complete forelimb fracture into adulthood. Direct U/Th dating on one associated lion mandible (MGGC 22648) places it in the MIS 6, making it one of the earliest securely dated palaeopathological records for the cave lion lineage. Clinical CT (0.8 mm slices, 0.33 mm resolution) and macroscopic examination reveal a long spiral fracture of the diaphysis, with malunion, overlap and rotational displacement of the shaft, marked shortening, and a hypertrophied deltoid crest. A dense, smoothly marginated circumferential callus and localised cortical thickening along the helical fracture trace document advanced remodelling and robust union, while the absence of sequestrum, involucrum and cloacae allows a purely traumatic etiology to be established. Complete remodelling of the fracture, minimal early arthrosis at the joint and experimental data on age-related healing collectively indicate that the injury occurred before full skeletal maturity, most likely during late juvenile development. Fully fused epiphyses and later degenerative changes show that the individual survived to advanced age despite altered limb geometry and reduced mobility during growth. This CT-based case provides unprecedented osteopathological evidence that juvenile Eurasian lions could recover from major forelimb trauma and reach adulthood, demonstrating high individual resilience and supplying a critical datapoint for quantifying injury tolerance, survival, and life history strategies in extinct large carnivores.