Modern Weights and Measurements of Wild Lions

[GuateGojira]

(04-07-2020, 11:21 PM)Pckts Wrote: Velizar Simeonovski



The lessons of a growing lion:
What a skull of about 18* months old lion could tell about evolution
A) skull of a subadult male lion from Kenya - (Measurements; GL 275 , KBL 262.5, P4 35.3, m1 28.3)
B) an adult male from Botswana (Measurements; 395.6, KBL 340, P4 34.6 , m1 26 )
1 Growth and development:
As it can be seen it is obvious that the young lion (skull) would have a long away to grow until it reaches its adults size. Unlike the skull though the completely erupted permanent dentition of the young specimen is in its full adult size. This discrepancy between the growth rate of the dentition and the cranium gives an opportunity to illustrate the elusive but important process of the locally-specific growth (LSG) - a process of different speed, rate and or direction of growth of neighboring areas of the skull (and other bones).In this particular case in the maxilla and the mandible. Although LSG is likely a wide spread process, it is hard to be observed and illustrated, and as a consequence to define the areas which differ in growth. (To make the things even more difficult the differences in the growth rate could only be temporal )On the picture - The areas underlined with blue needs to retain their size (by holding the growth or modifying its direction) in order not to increase the volume of the alveoli and to loose the teeth. But the neighboring areas in red will grow freely until reaching the adult size (approximately as in the adult lion skull) . What are the mechanisms that determine those spatial differences of the growth on the local level, what those mechanism are depended on, and what controls them is unknown. But all of the skull /bone characteristics used in taxonomy and used for functional interpretations are product of the process of the growth - the general growth process but also the locally specific ones.
*the age is estimated based on teeth eruption see: Smuts, G.L., Anderson, J.L., Austin, J., 1978. Age determination of the African lion. J. Zool.185, 115–146.
2 Paleo -diet
The permanent teeth in cats are erupting in their full adult size, although the animal itself is still far from reaching the adult size. Since the teeth are completely developed they arrest their growth, which includes also the development (forming) of the dentin - i.e. the exchange of substances between the dentin and the environment (including that of isotopes) stops there. So any isotope analysis in cats based on dentin would provide data about the food habits of the animal at the time when it is about 30% - 40% smaller of the regular adult size.

*This image is copyright of its original author

Very usefull information. That means that unless that we know if the animal was fully adult or not, we can't use dentition as surrogate of size and weight, as the dentition is already fully grown even when the animal itself is istill not an adult. Sad news for some of us that use dentition to get body size of prehistoric animals. Reply