Stereocephalus tutus Lambe 1902
Creators: name: Lambe L., M.
Publisher: name: Zenodo
Year: 1902
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Dinosauria
Stegosauridae
Stereocephalus
Stereocephalus tutus

description: Stereocephalus tutus. Sp. nov. Plate XI, plate XII, figs. 1, 2, 3, 4 and 5, and plate XXI, &amp;filig;gs. 6, 7 and 8. The speeimen of Which views from above, from the side and from below are given on plates XI and XII, represents part of the plate-protected cranium of a herbivorous dinosaur, that is, apparently, quite distinct from any hitherto described. With the head was found a transverse series of coössi&amp;filig;ed sharply keeled scutes which will be described farther on. The part of the head preserved is strongly convex transversely, but only moderately so from front to back. Goôssi&amp;filig;ed plates cover the whole of the upper surface and are continued down on the vertical sides. They are arranged with a certain amount of bilateral symmetry, are quite small at the centre and toward the back, but are larger in front and very much more so on the sides. They are for the most part irregularly &amp;filig;ve or six sided, with rather undulatory surfaces that are marked by an irregular, raised, structural cross-hatching, feebly suggestive of the surface markings of the plates of Nodosaurus textilis, Marsh. Small vascular openings and grooves are also numerous on the surface. The edges of the plates are as a rule angular and sometimes raised. Each plate has its limit de&amp;filig;ned by a deep circumscribing furrow, so that although they are coôssi&amp;filig;ed and form a continuous surface covering to the head, they do not lose their individuality. A rounded node, or an incipient keel is noticed on some of the plates. The removal of sandstone from the lower surface of the specimen revealed the bones of the palatal region (plate XII. &amp;filig;g. 2). The interpretation of these elements are as indicated by the letters. The back ends, only, of the palatines (P) are seen, meeting the pterygoids in a suture indicated at “ s. From here the latter bones (pt.) extend backward on either side of interpterygoid vacuities (v.). The ridge (pb.) represents the presphenoid and basisphenoid elements; it is bent posteriorly to one side in the specimen, which has been subjected to considerable pressure from above and is somewhat crushed behind. From this intel'pretation of the bones of the palate it would appear that the part of the armature preserved covers the upper part of the head near the union of the nasals With the frontals. No indication of the 01'bits can be detected and it is probable that they were placed far forward in the head. Part of a rib, having a T-shaped transverse section (Plate XII, &amp;filig;g. 5), such as is characteristic of the heavily armoured Slegosauría, was found separately but in the same locality, and is provisionally associated with S. tutus. The &amp;filig;nding of such a rib is sufficient evidence of itself to prove the existence, during the time of the deposition ofthe Belly River series, of a large dinosaur having a heavy protective covering of bony plates [table omitted] With the 11ead,just described, Were &amp;filig;ve keeled, bony scutes or plates that have since been found to &amp;filig;t together in the form of an arch (plate XII, &amp;filig;gs. 3 and 4), Whose sides curve forward as well as (lownward. This oblique curve places the lower, paired scutes, as seen when the arch is viewed from above, a little in advance of the upper pair which is again slightly in advance of the median plate The scutes rest on and are ossi&amp;filig;ed to a thickness of bone that constitutes the inner, continuous surface of the arch. This band of bone, ornamented above by paired ossicles, suggests the possibility of its being the back border of the posterior crest of the species to which the head armature, above mentioned, belonged. This suggestion is given credence from the fact that the concave edge of the band of bone on which the scutes rest is fractured, whilst the convex edge appears to be intact. Numbering the ossicles from the right, the junction between Nos. 1 and 2 was perfect, as were also those between Nos. 3, 4 and 5, but iii the case of Nos. 2 and 3 the fractured edges did not &amp;filig;t with su&amp;filig;icient exactness to remove all doubt as to their being placed side by side, although the continuity and symmetry of the curve of the under surface seemed complete. It is possible that one or two scutes are missing fro&amp;imath;n between Nos. 2 and 3, especially as fragments of similarly shaped scutes were found at the same spot. If an additional soute completed the series it probably would have been the mate of the present median one, or if two were required to &amp;filig;ll the gap (if such a gap exists) one would be on the median line, the other would correspond with No. 3 to form another pair. The addition of one or two scutes to the series would result only in extending and possibly flattening the curve. The median sente is apparently symmetrical, the others are asymmetrical, forming pairs with reversed lateral proportions. The scutes have an irregularly oval basal outline, are sharply keeled, with sloping sides shallowly excavated from the keel downward but convexly curved from front to back, their basal edges are de&amp;filig;ned by an engirdling furrow below which, at a lower level, they are laterally expanded to meet each other in a plane surface. A very small ossicle rises above this intermediate basal surface between Nos. 3 and 4. Vascular markings are conspicuous on the sides of the scutes. From the appearance of the outer, basal edges of scutes Nos. 1 and 5, it seems probable that these scutes constituted the lateral terminations of the series. [table omitted] Belly River series, Red Deer river, 1897. The tooth shown in &amp;filig;g. 12, is of the Stegosaurían type. It differs from those, of the Red Deer river district, referred to the two species of Palœoscincus, and is about twice as large as those of P. costatus. 1 t is &amp;filig;gured here with the idea that it may eventually prove to belong to S. tutus. It was collected below Berry creek, on Red Deer river, in 1901. A spinous dermal plate of massive proportions, &amp;filig;g. 13, A and B, is referred to this species on account of its similarity, in structure and surface markings, to the postcranial keeled scutes described above. This specimen was collected in 1897. Another large plate similar in general proportions to the above and nearly as large, as Well as numerous others of different sizes and of a variety of shapes, were collected in 1901.
description: Published as part of <i>Lambe L. M., 1902, New genera and species from the Belly River Series (mid-Cretaceous), pp. 25-81 in Geological Survey of Canada Contributions to Canadian Palaeontology 3</i> on pages 55-57, DOI: 10.5281/zenodo.3233762