Claosaurus agilis Marsh
An excerpt from:
Marsh, O.C. 1890. Additional characters of the Ceratopsidae, with notice of new Cretaceous dinosaurs. American Journal of Science, Series 3, 39: 418-426, with pls. v-vii.
Copyright © 2005-2009 by Mike Everhart
Created 06/27/2005 - Updated 02/14/2009
LEFT: The mounted specimen of Claosaurus agilis Marsh in the Yale Peabody Museum, adapted from an old photograph. The skull is added.
Wherein, O.C. Marsh renames Hadrosaurus agilis Marsh (1872) to a new genus, Claosaurus agilis, in recognition of certain distinct characters. See Marsh, 1872 for the original description.
O.C Marsh -- New Cretaceous Dinosaurs
Claosaurus agilis, gen. nov.
The small dinosaur described by the writer, in 1872, as Hadrosaurus agilis* proves on investigation to represent a distinct genus which may be called Claosaurus. The remains of this reptile were found by the writer, in the Pteranodon beds of the Cretaceous, near the Smoky Hill River in western Kansas. After the species was described, the writer again visited the locality and secured other portions of the skeleton, so that now the more important parts are available for comparison.
The teeth are of the Hadrosaurus type, but, apparently only a single row was in use at one time. The cervical vertebrae are very short, and strongly opisthocoelian. The fore limbs were very small. There are seven vertebrae in the sacrum, firmly coössified. The caudals are longer than wide and the tail was quite elongate.
AM. JOUR. SCI - THIRD SERIES, VOL. XXXIX, NO. 233 - MAY, 1890
424 O. C. Marsh -- New Cretaceous Dinosaurs
The astragalus was closely applied to the end of the tibia, but not coössified with it. The fibula is strong and complete, with both ends nearly equal in size. There were three functional digits in the pes, with their metatarsals moderately elongate. The terminal phalanges are broad, and ungulate in form.
The ilium is intermediate in form between that of Hadrosaurus and Stegosaurus, and its general characters are shown in the cut below. The portion in front of the acetabulum is very slender and elongate. The face for the pubis is much smaller than that for the ischium.
The present genus is very distinct from Nodosaurus which was described by the writer from a higher horizon of the Cretaceous. The present animal had apparently no dermal armor and was of much more slender proportions. When alive, it was probably not more than 15 feet in length.
Above: Ilium of Claosaurus agilis, Marsh; right lateral view; a, acetabulum; is surface for ischium; p, surface for pubis (Marsh, 1890)
Credits: Dr. Jane Davidson provided a copy of the Marsh 1890 paper used to prepare this ePage.
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