Change search
ReferencesLink to record
Permanent link

Direct link
Embryonic shell structure of Early–Middle Jurassic belemnites, and its significance for belemnite expansion and diversification in the Jurassic.
Swedish Museum of Natural History, Department of Paleobiology.
Musée national d’histoire naturelle, Luxembourg.
Musée national d’histoire naturelle, Luxembourg.
Università ‘La Sapienza’, Roma, Italy.
2014 (English)In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, no 1, 49-65 p.Article in journal (Refereed) Published
Abstract [en]

Early Jurassic belemnites are of particular interest to the study of the evolution of skeletal morphology in Lower Carboniferous to the uppermost Cretaceous belemnoids, because they signal the beginning of a global Jurassic–Cretaceous expansion and diversification of belemnitids. We investigated potentially relevant, to this evolutionary pattern, shell features of Sinemurian–Bajocian Nannobelus, Parapassaloteuthis, Holcobelus and Pachybelemnopsis from the Paris Basin. Our analysis of morphological, ultrastructural and chemical traits of the earliest ontogenetic stages of the shell suggests that modified embryonic shell structure of Early–Middle Jurassic belemnites was a factor in their expansion and colonization of the pelagic zone and resulted in remarkable diversification of belemnites. Innovative traits of the embryonic shell of Sinemurian– Bajocian belemnites include: (1) an inorganic–organic primordial rostrum encapsulating the protoconch and the phragmocone, its non-biomineralized component, possibly chitin, is herein detected for the first time; (2) an organic rich closing membrane which was under formation. It was yet perforated and possessed a foramen; and (3) an organic rich pro-ostracum earlier documented in an embryonic shell of Pliensbachian Passaloteuthis. The inorganic–organic primordial rostrum tightly coating the protoconch and phragmocone supposedly enhanced protection, without increase in shell weight, of the Early Jurassic belemnites against explosion in deepwater environment. This may have increased the depth and temperature ranges of hatching eggs, accelerated the adaptation of hatchlings to a nektonic mode of life and promoted increasing diversity of belemnoids. This study supports the hypothesis that belemnite hatchlings were ‘a miniature of the adults’.

Place, publisher, year, edition, pages
2014. Vol. 47, no 1, 49-65 p.
Keyword [en]
Belemnites, embryonic shell, expansion, inorganic–organic shell matter, Jurassic
National Category
Geology Evolutionary Biology
Research subject
Ecosystems and species history
URN: urn:nbn:se:nrm:diva-1138DOI: 10.1111/let.12037OAI: diva2:782209
The Royal Swedish Academy of Sciences
Available from: 2015-01-20 Created: 2015-01-20 Last updated: 2015-01-20

Open Access in DiVA

Doguzhaeva_etal_2014_Embryonic(2075 kB)43 downloads
File information
File name FULLTEXT01.pdfFile size 2075 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text
By organisation
Department of Paleobiology
In the same journal
Lethaia: an international journal of palaeontology and stratigraphy
GeologyEvolutionary Biology

Search outside of DiVA

GoogleGoogle Scholar
Total: 43 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 34 hits
ReferencesLink to record
Permanent link

Direct link