Externally shelled cephalopods were important elements in open marine habitats throughout Earth history. Paleotemperatures calculated on the basis of the oxygen isotope composition of their shells can provide insights into ancient marine systems as well as the ecology of this important group of organisms. In some sedimentary deposits, however, the aragonitic shell of the ammonite or nautilid is...

Forty-four selected organic-walled dinoflagellate cyst species have been used for biozonation of the Bathonian, Callovian, and Upper Jurassic in North Bulgaria. The dinocysts were collected from 49 borehole sections two exposures. following dinocyst zones are herein introduced described: Lithodinium valensii–Gongylodinium erymnoteichos Concurrent-range Zone (lower–middle Bathonian); Ellipsoidic...

Conservation biologists and palaeontologists are increasingly investigating the phylogenetic distribution of extinctions and its evolutionary consequences. However, the dearth of palaeontological studies on that subject and the lack of methodological consensus hamper our understanding of that major evolutionary phenomenon. Here we address this issue by (i) reviewing the approaches used to quant...

him, and seeing two marks of fangs from which blood was oozing behind the ring and middle fingers, I tied a handkerchief very tightly round the forearm a little above the wrist, so as, if possible, to prevent the entrance of the poison into the system through the circulation, and ordering him to follow rne, we went over to the hospital which is about 200 yards from my house. On arriving there h...

Ammonoid sutures are geometric patterns formed by the intersection of septa and shell wall, have long been a diagnostic tool for ammonite researchers such applications as species identification, taxonomic relationships, ontogenetic change, functional evolutionary morphology, determination ecological niche, other aspects ammonoid paleobiology. Researchers interested in variety paleobiological qu...