A color pattern in an ammonoid was first reported and illustrated by d'Orbigny
    in 1842 (p. 185, Pl. 45, Fig. 4).  He recognized that the pattern preserved on the
    shell of a specimen of Asteroceras stellare (at that time known as Ammonites
    stellaris) from the Lower jurassic was a remnant of a biologically produced
    color pattern emplaced by the animal when it was alive.  Furthermore, he
    recognized that these kinds of patterns were observable only on well-
    preserved specimens.  These brief observations laid the groundwork for the
    now generally recognized conclusions that color patterns are scarce on am-
    monoids and that they have paleobiological significance.  Since d'Orbigny's
    time, there have been periodic reports of ammonoid color patterns (see Table
    I), and some workers have attempted to integrate this information into a greater
    understanding of the biology of ammonoids.
     
[There are no colour patterns observed in Paleozoic ammonoids, except for Homoceras and Gaitherites regarded as "False color patterns" (p.117)].