Stenopterygius: Prehistoric Animal of the Week

Happy Mother's Day to all you moms out there!  This week, in honor of mothers everywhere, we will be looking at a prehistoric reptile who's motherhood was preserved in fossilized form forever. (aw)  Check out Stenopterygius! 

Stenopterygius was a marine reptile belonging to the same order as Ichthyosaurus.  It measured about ten feet long from snout to tail and would have lived in oceans covering what is now Europe during the Early Jurassic period, about 180 million years ago.  The genus name, Stenopterygius, translates to "Narrow Wing". (or in this case, flipper)  There have been several species assigned to this genus. 

Stenopterygius quadriscissus life reconstruction by Christopher DiPiazza.

Like all ichthyosaurs, Stenopterygius was a reptile, but had evolved a body shape very similar to that of a fish for a marine lifestyle.  Instead of feet and claws, it had flippers, dorsal fin, and tail fluke.  Its eyes were large and it sported a narrow, almost beak-like mouth filled with many sharp teeth for snagging prey.  Stenopterygius and Ichthyosaurus were actually very similar in appearance but can be told apart by Stenopterygius' proportionally smaller head and shorter snout.

Fossilized skeleton of a mother Stenopterygius with young.

Stenopterygius would have spent it's entire life at sea but would have still needed to come to the water's surface to breathe.  Unlike modern sea turtles, which still need to come to shore to lay eggs on land, ichthyosaurs like Stenopterygius actually gave birth to live young in the water.  We know this because of beautifully preserved Stenopterygius fossils consisting of mothers with the skeletons of unborn babies still inside their body cavities.  We even know that the babies would have been born tail-first!  

That's it for this week!  Join me next time for another awesome prehistoric creature!  As always feel free to comment below or on our facebook page.  Is everyone excited for that new Godzilla movie coming out?  I sure am...  (hint-hint!)

References

Böttcher R. 1990. Neue Erkenntnisse über die Fortpflanzungsbiologie der Ichthyosaurier. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie) 164: 1-51

Maxwell, E. E.; Fernández, M. S.; Schoch, R. R. (2012). "First Diagnostic Marine Reptile Remains from the Aalenian (Middle Jurassic): A New Ichthyosaur from Southwestern Germany". In Farke, Andrew A. PLoS ONE 7 (8): e41692. doi:10.1371/journal.pone.0041692.

Michael W. Maisch and Andreas T. Matzke (2000). "The Ichthyosauria". Stuttgarter Beiträge zur Naturkunde: Serie B 298: 1–159.