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Do we really know what colour ichthyosaurs were? Dan Bensen
> In the book Dinosaurs and
> Prehistoric Animals (primarily by Dougal Dixon) it says, "The remains
> of pigment cells have also been preserved and the analysis of these
> suggests that the smooth, thick skin of Ichthyosaurus was a dark
> reddish-brown color in life." What ever became of that theory? Is it
> still valid?
Whitear (1956) is the one reference everyone alludes to when
discussing fossil pigment in ichthyosaurs (it is paper from _Ann. Mag.
Nat. Hist._). Whitear reported microscopic structures in
_Ichthyosaurus_ soft tissues that she interpreted as skin cells, and cells
with dark brown melanocytes. Obviously I have discussed this quite a
bit with David Martill, my supervisor and an authority on soft tissue
preservation in marine reptiles - judging by his published abstracts he
has formerly accepted this interpretation ('Some ichthyosaurs were
brown (Whitear 1956)' (Martill 1997)) but I can't recall what his take
is on it now. Many structures previously identified as 'skin cells' have
recently been reinterpreted as non-organic, so Whitear's identifications
need to be scrutinised.. also, if a fossil cell is brown, is that really an
accurate representation of pigmentation during life? Also, I am reliably
informed that Whitear's specimens are not of high quality (though this
might be due to recent degradation (L. Steel pers. comm.)).
I think this has been covered on the list before (check the archives).
On a related matter, it is probable that preserved ichthyosaur soft tissue
outlines are not ALL autolithified bacterial mats: Keller (1992 I think,
a _Kaupia_ paper) presented an alternative model. Those who work on
this area seem to agree that neither model explains ALL of the cases.
"Your little insurrection is at an end, your highness"
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