A novel species of fossil belemnites (a very successful group of Mesozoic cephalopods) was reported from collected new paleontological material on the Nordvik Peninsula by a team from the Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences (IPGG SB RAS).
Belemnites which remained important representatives of marine benthic fauna throughout the Jurassic and Cretaceous had dense bullet-shaped body (rostrum) which acted as a hydrodynamic counterbalance to their heavy tentacles, and used a combination of jet propulsion and fin undulation for locomotion, similar to modern squids. Fossil impressions confirm belemnites possessed a pair of fins attached to their internal skeleton. These were used for steady, slow-speed forward or backward movement, stabilizing the animal, and turning.
As active nektonic predators, they had prominent, well-developed eyes suited for hunting for fish, alongside small mollusks and crustaceans. Belemnites possessed an ink sac which they used to squirt dark, protective clouds, to evade higher predators. Some belemnite species reached 4 meters in length.
Relying on the geochemical data for a new belemnite species from the Nordvik section, its age is estimated at 139 million years, which is 6 million years older than previously thought for the studied outcrops.
The bottom line is, the new species should assigned to the Berriasian (Ryazanian) belemnite fauna.
The refined data have enabled the revision of the age and species composition in Lower Cretaceous fossil locality on the Nordvik Peninsula (northern Eastern Siberia).
Left: Lagonibelus pseudonecopinus Efremenko, sp. nov.; Right: Fig. 1–4. Buchia okensis (Pavlow, 1907); Fig. 5–14. Buchia volgensis (Lahusen, 1888); Fig. 15. Pachyteuthis acuta (Blüthgen, 1936); Fig. 16. Arctoteuthis repentina (Sachs et Nalnjaeva, 1964); Fig. 17. Lagonibelus necopinus (Gustomesov, 1960)
Sources: Official website of the RF Ministry of Science and Higher Education, and https://www.akm.ru/eng/press/paleontologists-have-discovered-a-new-species-of-ancient-mollusk-in-the-north-of-eastern-siberia/
Illustrations are provided by the researchers.
For more detail see the article by:
Dzyuba О.S., Efremenko V.D., Urman О.S., Shurygin B.N., Igolnikov А.Е., Yan P.А. – Revision of the Age and Species Composition of Some Early Cretaceous Belemnites of Northern East Siberia (Nordvik Peninsula). Paleontological Journal, 226, vol.60, no. 1, pp. 37–44