Paradise lost: Evidence for a devastating metabolic bone disease in an insular Pleistocene deer

This communication reports skeletal pathology in a Pleistocene endemic deer from the Mavromouri caves of Crete.

287 bones and bone fragments from Mavromouri caves are compared to 2986 bones from Liko Cave.

Bones were evaluated macroscopically, and measurements were made of morphometric characteristics of limb long bones. Representative bone specimens were examined radiographically and histologically.

Macroscopic hallmarks were loss of bone mass and increased porosity. The long bones were brittle, some of them having thin cortices, and others reduction of medullary cavities that contain dense Haversian tissue. The flat bones were spongy and fragile. Erosions of the metaphyses and articular surfaces were noted. Histological findings included: sub-periosteal resorption; loss of lamellar bone; enlargement of vascular canals; and remodeling of cortical bone. Two types of fibrous osteodystrophy were recognized in skeletal remains, subostotic and hyperostotic.

The deer of Mavromouri caves were affected by severe metabolic bone disease, likely nutritional secondary hyperparathyroidism. We hypothesize a multifactorial cause, including overgrazing, flora senescence, soil mineral deficiencies, and a prolonged period of climate extremes, degrading the Cretan deer habitat.

This is the first evidence of a metabolic bone disease causing this level of destructive pathology in an insular fossil deer.

The lack of absolute chronometric dates for the site limits potential linking with the prevailing environmental conditions.

Investigation of similar skeletal pathologies at other islands or isolated habitats is advised.