. Bulletin of the British Museum (Natural History), Geology. THE LIBYAN MIOCENE 503 III. DISCUSSION Weight. The skull of Megistotherium directs comparison among living carnivores with hyaenas, bears and the larger cats; the fossil has no single analogy among the present day stock and hence an attempt to reconstruct the whole animal from so few postcranial remains would be futile. Estimates can however be made of weight. Jerison (1961) made a revised statement of Dubois's formula for the ratio of brain/ body weight, incorporating in it a constant which varied through the Tertiary. Jerison expre
. Bulletin of the British Museum (Natural History), Geology. THE LIBYAN MIOCENE 503 III. DISCUSSION Weight. The skull of Megistotherium directs comparison among living carnivores with hyaenas, bears and the larger cats; the fossil has no single analogy among the present day stock and hence an attempt to reconstruct the whole animal from so few postcranial remains would be futile. Estimates can however be made of weight. Jerison (1961) made a revised statement of Dubois's formula for the ratio of brain/ body weight, incorporating in it a constant which varied through the Tertiary. Jerison expressed the formula as E = kP2'3^ where E is the brain weight, P the body weight and the value of k varies from 0-03 for Eocene to 0-12 for Recent. On the evidence of the endocranial cast it is known that the cranial capacity of Megistotherium cannot have been less than 300 cc. Substituting 300 g for E in the equation gives a body weight P of 1,000 Kg. A second estimate is based on the use of the humerus. The distal width of the humerus in Megistotherium (12-3 cm) is equal to that in a large brown bear, though the largest bears have humeri in excess of this (12 -6 cm recorded on a British Museum specimen). Individuals of Ursus arctos are known to reach 780 Kg; although it has not been possible to correlate directly individual weights and humeral widths; it seems reasonable to suggest that a bear with a humeral width of 12-3 cm could. Fig. 18. Megistotherium osteothlasies gen. et sp. nov. Holotype skull compared with lion, bear and hyaena Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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