STL Science Center

STL Science Center

24 April 2013

Lambe's Next Discovery

As has been discussed multiple times here, Lawrence Lambe was a prolific discoverer and describer of dinosaurs. Fortunately for him any rivalries he was a part of were not nearly as high profile as Marsh and Cope, which allowed him to focus a bit more on accuracy than volume; I think of the Marsh and Cope volumes of descriptions as having "machinegun accuracy" as opposed to the idea of one shot, one kill. Lambe was not, however, more often correct than Marsh or Cope, as the science has tweaked even his discoveries and ideas over the past century. Regardless, the point of bringing up Lambe is that we have his initial descriptions of this animal and can therefore look at the material secondhand rather than via many other sources. Over 200 scutes of armor, a good portion of a fore and a hind limb, a good portion of the cervical vertebrae articulated with the skull, pelvic and shoulder girdles and thoracic vertebrae were discovered together and delivered to Lambe. Lambe, however, did make an interesting mistake by placing Panoplosaurus, now known to be a Nodosaur, in the Stegosaur family (Stegosauroidea); he also assigned Euoplocephalus, another ankylosaur, to the stegosauria. Contained in the in depth descriptions of the skull we find that Lambe measured individual teeth in the skull and compared them to Stegosaurus, leading, in part, to his justification of this nodosaur as a stegosaur.

Lambe was not completely off, though, as the current convention holds that Stegosauria and Ankylosauria make up the clade Thyreophora as the Eurypoda (Scelidosauridae is also included outside Eurypoda but within Thyreophora). Lambe's attention to the detail of the armored scutes probably provided some of the best evidence, in later years, for the partitioning of the Eurypoda into Stegosauria and Ankylosauria, interestingly. I wish I had an exact paper to point to in reference to this change. Alfred Romer's 1956 Osteology of the Reptiles is widely considered, however, to be the definitive text for establishing Ankylosauria as a suborder within Thyreophora (Coombs and Maryanska. He divided the over 200 scutes into 7 major divisions; 1) Large plates; 2) Medium sized variable dimensions; 3) Moderately small keeled; 4) Small rectangular; 5) Small polygonal; 6) Small keelless; and 7) Irregularly shaped ossicles. He also included plates of the scutes, but my favorite plate is of the skull looking from front to back. Check it out:

References for today:
Coombs, W.P. and Maryanska, T. (1990). Ankylosauria. In Weishampel, D. B., Dodson, P., & Osmólska, H. (Eds.). . The Dinosauria. (456-483) Univ of California Press.
Lambe, L. M. (1919). Description of a new genus and species (Panoplosaurus mirus) of armored dinosaur from the Belly River Beds of Alberta. Transactions of the Royal Society of Canada series, 3(13), 39-50.

No comments:

Post a Comment