Dear everybody,

Prof Deeming has just published an excellent paper about
The reproductive biology of dinosaurs.

I include the abstract and citation below.

Xavier


[Palaeontology, Vol. 49, Part 1, 2006, pp. 171–185]

ULTRASTRUCTURAL AND FUNCTIONAL
MORPHOLOGY OF EGGSHELLS SUPPORTS THE IDEA
THAT DINOSAUR EGGS WERE INCUBATED BURIED
IN A SUBSTRATE

Abstract:

The reproductive biology of dinosaurs is of great
interest, particularly in light of the many fossil eggs assigned
to this group. The ultrastructural characteristics of dinosaur
eggshells are examined in order to calculate water vapour
conductance, which indicates the nesting environment. Data
were mainly derived from the literature but new values are
also presented. Allometric analyses were carried out on a
variety of shell parameters against predicted egg mass, and
comparison was made with allometric equations for bird
eggs. Shell thickness was generally larger than seen for extant
birds. Total pore number and pores per unit area were similar
to values predicted from bird eggs. Total pore area
showed an isometric increase with egg mass, parallel to the
relationship for birds, but the constant value was an order
to magnitude higher than the bird values. Pore radius was
unaffected by egg mass. Water vapour conductance showed
an allometric increase with egg mass, parallel to the bird values,
but for any given egg mass values for dinosaurs were an
order of magnitude higher. Mass-specific water vapour conductance
was unaffected by egg mass but was an order of
magnitude higher than the bird values. Water vapour conductance
per pore showed an allometric decrease with egg
mass but again the predicted values were an order of magnitude
higher than for bird eggs. The ultrastructural characteristics
of dinosaur eggshells indicate that the nesting
environment had to be saturated with water vapour and that
dinosaur eggs had to be fully buried in a substrate. In this
sense, therefore, dinosaur eggs resemble more those of modern
reptiles than those of birds. As a consequence, maintenance
of incubation conditions would have depended on the
prevailing environment.