This fossil giant squid has just been published (10/01/06). Here's a quick summary, my words. (Thanks to Monty for providing the original article) Potentially the largest fossil coleoid to be discovered to date was published in January 2006 by Kazaushiga Tanabe, Yoshinori Hikida and Yasuhiro Iba. It consisted of one half of an enormous set of jaws discovered in Late Cretaceous Campanian (83-71 mya) sediments at Wakkaweenbetsu Creek, Nakagawa Town, Hokkaido, Japan. The fossil was composed of a black phosphatic material and was contained inside a calcareous nodule. Included with the specimen were numerous bivalves and specimens of the heteromorphic ammonite Polyptychoceras. The fossil came from the Upper Yezo Group of mudstones, ‘Yezo’ being an old name for Hokkaido. The fossil is an upper jaw that measures 97mm in length and is 22.5mm wide at its maximum point. It has a very sharply pointed rostrum that is angled acutely, and both the inner and outer lamellae are present. In order to determine the systematic relationship of the specimen, the authors performed a cladistic analysis based on 5 morphological characteristics of the jaw in comparison with 22 other extant coleoids and Nautilus. As a result of this and from a physical comparison of the shape of the rostrum and wings, the authors determined that the specimen is closest to the sub-order Oegopsina. The authors then attempted to estimate a total size for the animal, by examining the ratio of the maximum length of the upper jaw (LUJ) to total mantle length (ML) in eight extant coleoid species. Applying these derived ratios to the fossil jaw and plotting it along with these other specimens, it was concluded that the Mantle Length was probably akin to Architeuthis. The jaw is similar to Architeuthis not only in overall size, but in shape, and structure. It differs in that the crest margin is more convex in shape and has more prominent growth lines on the inner lamella. The authors conclude that this specimen represents a large new species, Yezoteuthis giganteus, that would have been present in Late Cretaceous Northwest Pacific along with many small ammonoid and nautiloid shelled cephalopods. The jaw is currently housed at the Nakagawa Museum of Natural History. TANABE, K., HIKIDA, Y., and IBA, Y., Two coleoid jaws from the Upper Cretaceous of Hokkaido, Japan. Journal of Paleontology 80 (1) 138-145, 2006.