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Extra resources for 8th International Symposium Cephalopods – Present and Past, August 30 – September 3, 2010, University of Burgundy & CNRS, Dijon – France. Abstracts Volume

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However, the actual fusion of the foregut and midgut rudiments, for example, is not observable in the living embryo; it has to be “reconstructed” from histological sections made from embryos preserved at successive developmetal stages. From such an ontogenetic time series, one can build a motion picture that overcomes the difficulties of viewing morphogenetic changes by looking at different aspects of the embryo at successive developmental stages. Moreover, time-lapse photography obtained from living embryos over days (possibly weeks) provides an essential tool for showing the true dimensions of organs, unaltered by the form changes related to fixation procedures used in histological work.

Consequently, cephalopods possessing endocones may have originated from more than one lineage within the Ellesmerocerida. Although the stratigraphic relationships between the earliest known pilocerids and proterocameroceratids is equivocal, study of the endosiphuncular deposits suggests that those of the Piloceratidae, Manchuroceratidae and the younger Allotrioceratidae and Najaceratidae, are distinctly different to those of the Proterocameroceratidae and Endoceratidae. Other differences include overall shell shape (cyrto-breviconic in the Piloceratidae and Manchuroceratidae, longiconic in the Proterocameroceratidae) and septal neck morphology (holochoanitic to macrochoanitic throughout the Piloceratidae, Manchuroceratidae, Allotrioceratidae and Najaceratidae).

Import data indicate that more than 579,000 specimens were imported between 2005 and 2008, mainly from China, Indonesia, and the Philippines. Nearly all of these specimens were wild-harvested. Israel, the European Union, and Thailand are among the other known non-range countries involved in international nautilid trade. Certain intrinsic life history traits (such as longevity, delayed maturation, lengthy gestation, and small number of eggs produced per breeding season), in combination with extrinsic factors (such as selective harvest, predation, habitat fragmentation, and climate change), render nautilids more susceptible to unregulated harvest and increase their risk of extinction.

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