Cephalopod egg fossil

The first was an apparent clutch of eggs preserved in the sediment that filled in the living chamber of a harpoceratid dating back to the Toarcian age of the Jurassic period.

An additional less plausible case has been reported from Kamchatka where an egg clutch was purportedly associated with a Desmophyllites dating back to the early Triassic.

However a later summary of ammonite embryos from the same age and location does not mention any eggs being known and Desmophyllites is a Late Cretaceous genus, so this report is not reliable.

Lehmann's specimen from the Lias, reported in 1966, was a pouch of about 50 empty egg capsules lying in the innermost part of a mature macroconch's body chamber.

[6] The researchers described the other specimen, reported by Muller in 1969 from the Trias, as a "carbonized ghost" that preserved very little detail, not even showing signs of individual egg capsules.

[7] In 2009, Steve Etches, Jane Clarke, and John Callomon reported the discovery of eight clusters of ammonite eggs in the Lower and Upper Kimmeridge Clay of the Dorset Coast in England.

[11] This leaves the most probable identity of the egglayers as Aulacostephanus and Pectinatites since they were the ammonites eudemic to the region at the time the egg fossils formed.

[13] Since the Kimmeridge Clay is so thoroughly studied the environment and depositional context is better understood for these ammonite eggs than those reported in the previous two examples.

[15] Unlike ammonites, no eggs of belemnites are currently known from the fossil record, although Steve Etches, Jane Clarke, and John Callomon have observed that this may be due to a lack of people actually looking for them.