Dynamosaurus imperiosus Osborn, 1905, gen. et sp. nov.
Creators: name: Osborn, H. F.
Publisher: name: Zenodo
Year: 1905
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Dinosauria
Tyrannosauridae
Dynamosaurus
Dynamosaurus imperiosus

description: Dynamosaurus imperiosus gen. et sp. nov. <i>Type.</i> <b>—</b> Numerous dermal plates and many parts of the skeleton. Collection of 1900, American Museum No. 5866, from Seven Mile Creek, six miles north of Cheyenne River, Weston County, <i>Wyoming</i>. The type of this skeleton was found <i>by</i> the American Museum expedition of 1900 under <i>Mr</i>. Barnum Brown, whose <i>preliminary</i> report was as follows: <b>“</b> It consists of lower <i>jaws</i>, having that large foramen characteristic of <i>Ceratosaurus,</i> serrated teeth of uneven height joined by cartilage, not anchylosed. Concavo-concave and <i>plano-concave</i> vertebrae of lumbar-dorsal <i>region</i> are deeply excavated on sides and bottom <i>rising</i> to plane surface in <i>region</i> of canal; extremely hollow and as in <i>Morosaurus</i> not having <i>spines</i> and transverse processes united to centra. Sacral vertebrae 3 <b>?</b> Post-sacral vertebrae, of which seven were embedded in stone matrix, show plano-plano surfaces. Transverse processes united to centra. Nature of cervical vertebrae not determined. Ribs large, not greatly curved in dorsal <i>region</i>, <i>tapering</i> gradually to those of cervical <i>region</i>. But few chevrons were found, those of extreme length <i>in</i> proportion to size of vertebrae. <b>”</b> <i>Generic characters</i>. <b>—</b> Carnivorous dinosaurs with twelve to fifteen mandibular teeth <i>of</i> rounded to flattened form. Anterior truncate teeth reduced or <i>wanting</i>. <i>Irregular</i> bony plates developed on the back or <i>sides</i> of the body. <i>Alveolar</i> partitions between the mandibular teeth extending upward into triangular plates on the inner sides of the <i>jaws</i> above the borders of dentaries. Specific <i>characters.</i> <b>—</b> Twelve to thirteen mandibular teeth. This animal is distinguished by the presence of superficial bony dermal plates which extended either along the dorsal or side lines of the body, by the reduction of the number of teeth, by the apparent absence of truncated anterior teeth, by the rounded rather than lenticular form of the teeth, by the presence of a row of triangular upgrowths of the dental alveoli on the inner sides of the jaws. In <i>Deinodon</i> there will probably be found a larger number of teeth, and some of the anterior teeth of the jaw will be found to be truncated and serrate posteriorly as in <i>Allosaurus.</i> <i>Dentition.</i> — The species <i>D. imperiosus</i> appears to be distinguished by the presence of from twelve to thirteen mandibular teeth. The inner view of the mandibular ramus (Fig. 1) exhibits a small anterior alveolus for a vestigial tooth followed by twelve fully functional teeth, behind which there is another partially closed alveolus; thus there appear to have been two reduced and twelve functional teeth. The dentition is not homodont, every tooth differing slightly in its section and in the position of the serrate edges, also in size. The third functional tooth from the front is apparently the largest, the measurements of the <i>crown</i> being a. p. 43, tr. 33, <i>vert</i>. 82 mm. The last functional tooth <i>is</i> decidedly smaller, the <i>crown</i> measuring a. p. 19, tr. 11, vert. 15 mm. <i>Jaws.</i> — Between the teeth <i>are</i> a series <i>of</i> triangular osseous plates, which <i>appear to</i> be upward continuations <i>of the</i> alveolar walls which separate at the base from the edge of the dentary.
description: Published as part of <i>Osborn, H. F., 1905, Tyrannosaurus and other Cretaceous carnivorous dinosaurs, pp. 259-265 in Bulletin of the American Museum of Natural History 21</i> on pages 263-264, DOI: 10.5281/zenodo.1038222