The embryonic conch structure as a supposed imperative factor on the hatchling dispersal and geographical expansion of belemnites: an example of Callovian (Middle Jurassic) pachybelemnopseins from Aragón (NE Spain)

Scanning electron microscopy, energy dispersive spectrometry and taphonomic analysis are applied for studying of about 250 shells of the pachybelemnopsein belemnites Hibolithes and Pachybelemnopsis ...