Nautilus remains of great interest to palaeontologists after a long history of actualistic comparisons and speculations on aspects of the palaeoecology of fossil cephalopods, which are otherwise impossible to assess. Although a large amount of work has been dedicated to Nautilus ecology, conch geometry and volumes of shell parts and chambers have been studied less frequently. In addition, altho...

The idea that physical processes involved in biological development underlie morphogenetic rules and channel morphological evolution has been central to the rise of evolutionary developmental biology. Here, we explore this idea in the context of seashell morphogenesis. We show that a morphomechanical model predicts the effects of variations in shell shape on the ornamental pattern in ammonites,...

Ammonites are among the best-known fossils of the Phanerozoic, yet their habitat is poorly understood. Three common ammonite families (Baculitidae, Scaphitidae, and Sphenodiscidae) co-occur with well-preserved planktonic and benthic organisms at the type locality of the upper Maastrichtian Owl Creek Formation, offering an excellent opportunity to constrain their depth habitats through isotopic ...

Most paleo-episodes of ocean acidification (OA) were either too slow or too small to be instructive in predicting near-future impacts. The end-Cretaceous event (66 Mya) is intriguing in this regard, both because of its rapid onset and also because many pelagic calcifying species (including 100% of ammonites and more than 90% of calcareous nannoplankton and foraminifera) went extinct at this tim...

The functional signiŽ cance of frilled septa and complex sutures in ammonoids has generated ongoing debate. The ‘classic’ hypothesis envisages ammonoid shells and septa as designed for resisting ambient hydrostatic pressure, complex sutures being the evidence of strength in shells for colonization of deep habitats. Here we address the ‘suture problem’, focusing on the analysis and interpretatio...

This paper describes and illustrates three newly discovered Late Hettangian ammonite specimens from the “Dorsale calcaire” (Calcareous Range) of the internal units of the Rif (Northern Morocco). Two additional Early Sinemurian ammonite specimens are also studied and all the Early and middle Lower Jurassic ammonites collected earlier in this area and illustrated in the literature are included in...

Three ammonites; Ermoceras cf. coronatoides Douvillé, Teloceras labrum Buckman, and Normannites gr. braikenridgii (Sowerby); have been recorded for the first time from latest early Middle, to Late Bajocian of Wadi Huni biomicritic marly limestone Zerqa in Dier-Alla area. This fossil fauna is comparable with other levant countries.