Scapherpeton tectum, Cope

Lambe L. M., 1902, New genera and species from the Belly River Series (mid-Cretaceous), Geological Survey of Canada Contributions to Canadian Palaeontology 3, pp. 25-81 : 31-32

Scapherpeton tectum, Cope Plate III, figs. 4-8 .

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Scapherpeton tectum, Cope. 1876 . Proc. Acad. Nat. Sci. Philadel. vol. xxviii, p. 355. This species is represented iu the collection by a number of trunk vertebras and atlases. Almost as many of the latter as of the former were obtained, a peculiarity that can be accounted for only by supposing that the stout, compact form of the atlas aided in saving it from breakage.

The trunk vertebrae, of which one of the best is figured, are biconcave, with well developed pre- and postzygapophyses, a backwardly directed, stout neural spine whose basal front extends forward as a prominent keel between the prezygapophyses. A number of foramina enter the spine in its upper half where it is seen to be hollow. The centrum is pinched or laterally compressed below, so as to produce a strong carination inferiorly, and an elongation of the articular cups downward. The uotochord is not persistent the foramince for its entry into the central body are conspicuous at the bottom of the articular cups. The diapophysis is directed outward and backward and has an irregular, figure 8 shaped, transverse section, as described by Cope. A foramen enters the base of the diapophysis from in front, another from behind and, on the right side of the vertebra figured, one also enters from below. In figure 4 the neural spine and the postzygapophyses are restored from a separate spine to the base of which the zygapophyses remain attached. In one of the larger vertebrse, the roof of the neural canal is angularly vaulted and the front border of the arch between the prezygapophyses is notched and turned slightly upward. Numerous small foramina occur in all parts of the vertebrae.

Three figures are given of one of the largest and best preserved atlases, to show the two facets for articulation with the occipital condyles of the skull, the anterior process projecting from the centrum between the two facets, and the articular cup behind. A number of foramina occur in the concave inferior stirface of the atlas. Other foramina occur as depicted.

Measurements.
Of trunk vertebra:	Length of centrum	Height of articular cups,	Breadth of same	Diameter of notochordal foramen	Antero-posterior diameter of neural spine measured from between postzygapophyses,,	Of atlas:	Extreme length	Extreme breadth	Height of facets for articulation with condyles of skull	Breadth of same	Height of articular cup	Width of same '	M.	008	006	" 004	001	0035	007	0095	003	004	0037	003
Length of centrum	008
Height of articular cups,	006
Breadth of same	" 004
Diameter of notochordal foramen	001
Antero-posterior diameter of neural spine measured from between postzygapophyses,,	0035
Of atlas:
Extreme length	007
Extreme breadth	0095
Height of facets for articulation with condyles of skull	003
Breadth of same	004
Height of articular cup	0037
Width of same '	003

Belly River series. Red Deer river, 1901 The position of this genus was not definitely determined, but its author considered that the structure of a proximal limb bone, and the form of the diapophyses of the vertebrae referred it with much probability to the Urodela , and that the biconcave centra placed it nearest to the Amblystomidae. Also that other structural points indicated a family different from any of those now living.

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A small right maxilla of which, two views are given ( plate XV , figs. 16 and 17) is of interest. It is almost perfect anteriorly. Its upper border comes to a sharp edge, from which posteriorly a small fragment has been broken off, as indicated in the figure. A ridge extends the length of the bone on the inner side at about mid-height at the centre but curving downward to near the lower margin in front. Posteriorly two sutural surfaces occur, one on the inner side in continuance of the ridge, the other emargiuates the upper border. Between these two surfaces the bone is shallowly excavated. Six large foramina occur in a line at about mid-height in the anterior half of the outer surface. The lower border of the maxilla is broad and bears eight subquadrately elliptical toothbases with their greater diameters transverse to the length of the jaw. Small foraminal openings occur encircling the outer surface of the tooth-bases. Teeth have been lost from the jaw leaving shallowly depressed interspaces.

The relationship of this bone is not clearly understood, but it is for the present associated with Scapherpeton tectum . It occurred with and is of the same colour and texture as the vertebrae of that species.

Figures

PLATE III. Fig. 1. Trachodon (Pteropelyx) marginatus, Lambe, inner side of left ramus of lower jaw, showing the teeth; one-half the natural size. Page 73. e, coronoid process; a, symphyseal surface; b, inner wall of dental chamber; c, mandibular groove; d, foramen. Fig. 2. Trachodon (Pteropelyx) sclwyni, Lambe, inner surface of teeth of lower jaw, to show succession natural size. Page 69. Fig. 3. Grinding surface of teeth of same specimen; natural size. Fig. 4. Scapherpeton tectum, Cope, dorsal vertebra, from the left side; twice the natural size. Page 31. Fig. 5. View from the front, same specimen. Fig. 6. Scapherpeton tectum, atlas, front view; twice the natural size. Fig. 7. The same, viewed from behind. Fig. 8. The samc, side view from the lcft. y, diapophysis _; z, prezygapophysis; ê, postzygapophysís l; s, neural spine 5 x, anterior articural cup; w, neural canal; v, facet for occipital condyle of skull.

Fig. 8. The plastron of Baena hatcheri; from Red Deer river. One-half natural size. /&',Intergular shield; G, Gular do.; HUM, Humeral do.; PEC, Pectoral do.; AB, Abdominal do.; FEM, Femoral do.; AN, Anal do.: ep, Epiplastral bone; entp, Entoplastral do.; hyp, Hyoplastral do.; msp, Mesoplastral do.; hpp, Hypoplastral do.; xp, Xiphiplastral do.; * centre of front margin of carapace

Fig. 4 Plastron of Adocus variolosus one-sixth the natural size. ;

PLATE XV. Fig. 1. Ornithomimus altus, Lambe, caudal vertebra, superior view, natural size. Page 52. Fig. 2. View of right side of same. Fig. 3. Ornithomimus altus, caudal vertebra, superior view natural size. Page 52. Fig. LL. The same, inferior view. Fig. 5. The same, right side. Fig (S. Ornithomimus altus, left sidc of lumhar vertebra of small individual natural size. Fig. 7. The same, superior view. Fig. S. The same, anterior view. Fig. Ü. Terminal phalanx of megalosauroid dinosaur, lateral view; natural size. Fig. 10. The same, proximal view. z, prezygapophysis i, postzygapoplıysis; s, neural spine e, transverse process. Fig, ll. Tooth of Deinorloıı cnrplanatus‘, Cope, side view; four times the natural size. Page 45). Fig. 12. Transverse section of the same. Fig. 13. Ptilodus primaevus, Lambe, right man libular rztmus,c.\' ternal view; enlarged four times. Page 79. Fig. 1 -1. The same, internal view. pflf, fourtli prernolar; mf, first molar i, socket for incisor; n, socket for second molar. Fig. 15. Boreodon matutinus, Lambe, premolar. side view, four times natural size. Page TQ c, cingulum. Fig. 16. Right maxillary bone, (provisionally associated with Scapherpelnu tectmn), external view, four times thc natural size. Fig. ii. Inferior' view of the samc, similarly cnlargcd. Page 32. Fig. is. Prcınaxillary bone of Diphyodus longirostris, Lambe, inferior view; enlarged four times. Page 30. Fig. 19. Transverse section of samc, similarly enlarged. t, tooth-base m, interspace.

FIG. 16.-—Sacrum provisionally associated with Monoclonius dawsoni, less than one-seventh the natural size 2 superior view.