Dinilysia

Dinilysia
Temporal range: Late Cretaceous, 85 Ma
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Illustration of the skull and vertebral column
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Reptilia
Order:Squamata
Clade:Ophidia
Family:†Dinilysiidae
Genus:†Dinilysia
Woodward, 1901
Type species
Dinilysia patagonica
Woodward, 1901

Dinilysia (meaning "terrible ilysia") is an extinct genus of snake from the Late Cretaceous (Coniacian) of South America. The snake reached a length of 6–10 feet (1.8–3 meters) and preyed on smaller animals. The shape of the animal's skull does support the suggestion that snakes were burrowers during their ancestry; it is clear that Dinilysia was terrestrial.

Hypothetical appearance of Dinilysia patagonica (reconstruction based on skeletal and other features).

Physiology and Lineage

Bony inner ear labyrinth of Dinilysia patagonica

The Dinilysia patagonica is a stem snake that is very closely related to the original ancestor of the clade of crown snakes.[1] Once the fossil of the snake was discovered, an x-ray computed tomography was used to build a digitized endocast of its inner ear. The results displayed that the Dinilysia patagonica's inner ear anatomy had 3 main parts. It had a large spherical vestibule, large foramen ovale, and slender semicircular canals in its inner ear.[1]

Especially significantly, the spherical vestibule is an inner ear organ that is a morphological signature of burrowing snakes. A large spherical vestibule does not exist in aquatic or generalist (both land and water) snakes, only in snake species that burrow. A spherical vestibule contains a large saccular otolith, which transmits vibrations to the snake's brain.[1] Due to a spherical vestibule, the Dinilysia patagonica was a species especially sensitive to low-frequency ground vibrations rather than airborne frequencies.

The surmounting evidence displays that Dinilysia patagonica was more than likely a terrestrial burrower from the Cretaceous era. This discovery also extends its evidence to the fact that a burrowing habit predates the lineages of modern snakes. These ancestral snakes detected predators and captured prey specifically using low-frequency ground vibrations.

References

  1. 1 2 3 Yi, Hongyu; Norell, Mark A. (2015-11-01). "The burrowing origin of modern snakes". Science Advances. 1 (10): e1500743. doi:10.1126/sciadv.1500743. ISSN 2375-2548. PMC 4681343. PMID 26702436.
  • Caldwell, M.W. & Albino, A.A., 2002. Exceptionally preserved skeletons of the Cretaceous snake Dinilysia patagonica, Woodward, 1901. Journal of Vertebrate Paleontology 22: 861-866.
  • Fossils (Smithsonian Handbooks) by David Ward
  • Dinosaurus: The Complete Guide to Dinosaurs by Steve Parker. Pg. 99
  • Fossil Snakes of North America: Origin, Evolution, Distribution, Paleoecology (Life of the Past) by J. Alan Holman


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