Parapuzosia seppenradensis. (replica), originally uploaded by muzina_shanghai.

I’m still in a paleontological mood after yesterday’s big news, so here is another big fossil…literally. Parapuzosia seppenradensis is desmoceratid ammonite from Late Cretaceous Germany, and it is the largest known ammonite species. An incomplete specimen found in 1895 had a diameter of 1.95 meters (~6 ft), and in life it is estimated to have been 2.55 meters (over 8 ft) across.

As big as P. seppenradensis was, it was by no means the largest prehistoric cephalopod. That honor goes to the giant Ordovician orthoconic (i.e. straight-shelled) nautiloid Cameroceras, which may have been as much 11 meters long (~36 ft). Of course that is the topic for another post…

Ammonite, originally uploaded by elrina753.

This awesome replica of a turrilitid ammonite is from the Cretaceous Seas diorama at the American Museum of Natural History in New York City. I don’t know exactly which type of turrilitid this is, but my best guess is the genus Pseudhelicoceras.

Members of the ammonite family Turrilitidae are characterized by shells that are not typical tight spirals—a condition known to paleontologists as heteromorph. It isn’t clear what ecological niche the turrilitids filled, but at least some species are thought to have drifted up and down in the water column. They lived world-wide during the late Cretaceous period, but, like all ammonites, they went extinct in the same global catastrophe that killed off the dinosaurs 65 million years ago.

Ammonite washbasin from HighTech Design Products

El Ray, originally uploaded by Potatojunkie

The career of Ray Harryhausen, the master of stop motion animation, has spanned eight decades. His memorable creations include Mighty Joe Young (1949), the cyclops form The 7th Voyage of Sinbad (1958), the warrior skeletons of Jason and the Argonauts (1963), the dinosaurs of The Valley of Gwangi (1969), and Bubo, the mechanical owl from Clash of the Titans (1981). He is also responsible for two memorable movie cephalopds.

It Came From Beneath The Sea (Columbia Pictures, 1955)

This black and white film tells the story of a rampaging giant octopus, “blasted loose from the depths of the Pacific” by a hydrogen bomb. It terrorizes Pacific shipping lanes before turning it baleful gaze on San Francisco and the Golden Gate Bridge. It takes the United States Navy, an atomic torpedo, and a whole bunch of flame throwers, but the monster is eventually destroyed. (Ooops…Spoiler Alert!)

This may very well be the largest cephalopod in movie history (with one possible exception?), but it is hard to gauge exactly how big this octopus is supposed to be.  Judging by its size relative to the Golden Gate Bridge, a single arm could be almost 500 ft long, which would make it something like 30 times the size of the largest reported living octopus.

Mysterious Island (Columbia Pictures, 1961)

This adaptation of Jules Verne’s sequel to 20,000 Leagues Under the Sea features a number of Harryhausen classics: a giant crab, a Phorusrhacos (a type of prehistoric flightless bird), giant bees, and, the reason we’re here, the giant ammonite. I haven’t seen this movie in ages, but if I recall, the ammonite encounter occurs near the end of the film during an underwater salvage operation. With the island literally falling down around them, the American castaways (with the help of Captain Nemo’s men) attempt to use their hot air balloon to raise a sunken ship to the surface.

Ammonites are an extinct variety of cephalopod known for their distinctive coiled shells. They lived throughout the Mesozoic Era (251 to 65.5 million years ago) and were wiped out in the same event that ended the dinosaurs. Most are believed to have lived in the open ocean, and the largest known species (Parapuzosia seppenradensis of Late Cretaceous Germany) had a shell 6.5 feet in diameter. The movie ammonite is obviously a tad unrealistic, but that’s the whole point isn’t it?