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Sauropod incubation time and clutch size



From: Ben Creisler
bcreisler@gmail.com


A new online paper:



Graeme D. Ruxton , Geoffrey F. Birchard , and D. Charles Deeming (2014)
Incubation time as an important influence on egg production and
distribution into clutches for sauropod dinosaurs.
Paleobiology 40(3):323-330. 2014
doi: http://dx.doi.org/10.1666/13028
http://www.bioone.org/doi/abs/10.1666/13028

Individual egg size and clutch size of the largest of the dinosaurs
(the sauropods) are both smaller than might be expected for such large
oviparous organisms. We suggest that these effects can be understood
in the light of likely incubation times of sauropod eggs. Using
allometric relationships from extant birds and crocodilians, we
estimate that time from laying to hatching was likely to have been
65–82 days. If total predation risk varies with length of incubation
time, there may be egg sizes above which the advantages of larger
initial hatchling size are outweighed by the increased risk of
predation during the egg stage. Also, in seasonal environments there
will often be a finite limit to the period over which environmental
temperatures are high enough for egg development. Thus incubation time
may have been an important constraint explaining the small individual
size of sauropod eggs. We further suggest that for sauropods spatial
dispersal of eggs in small clutches was an adaptive strategy to
mitigate this high predation risk associated with long time of
exposure in the egg stage. Such a dispersive strategy brings several
benefits. Thus, incubation time may also be key to explaining the
surprisingly small clutch sizes.