. Bulletin. Natural history; Natuurlijke historie. Fig. 52. Postulated occlusal pattern in Stylinodon mirus as the mandible is brought up to occlude with the upper jaw; the major chewing stress is on the left side in the sequence. Arrows indicate the predominant motion of the lower jaws in a horizontal plane relative to the uppers, a) The lower jaws, which are initially slightly left of center and placed relatively posterior to the uppers, are brought up vertically and slightly forward to begin to occlude with the upper jaws, b) Tooth to tooth occlusion (contact) begins, first at the canines a
. Bulletin. Natural history; Natuurlijke historie. Fig. 52. Postulated occlusal pattern in Stylinodon mirus as the mandible is brought up to occlude with the upper jaw; the major chewing stress is on the left side in the sequence. Arrows indicate the predominant motion of the lower jaws in a horizontal plane relative to the uppers, a) The lower jaws, which are initially slightly left of center and placed relatively posterior to the uppers, are brought up vertically and slightly forward to begin to occlude with the upper jaws, b) Tooth to tooth occlusion (contact) begins, first at the canines and then progressively posteriorly, and the lower jaws are moved relatively anteriorly, c) With a short, powerful transverse stroke the lower jaws are moved from left to right of center and the right condyle might pivot laterally around the right postglenoid process. Masticatory Apparatus of Other Stylinodontids It appears, based on the close similarity between the morphologies of the jaws of Stylinodon and those of Ectoganus and also Psittacotherium, that the latter two had a jaw musculature extremely similar to that of Stylinodon. As described previously, the unworn posterior cheek teeth of Ectoganus bear bilophodont, transversely cuspidate ridges. As the upper and lower jaws of Ectoganus occluded, the anteroposterior motion of the jaws would produce a certain amount of shear between the transverse ridges of the upper and lower teeth. However, these crests, even when unworn, are relatively low, blunt and uneven, and they rapidly wore. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Peabody Museum of Natural History. New Haven : The Museum
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Keywords: ., bookcentury1900, bookcollectionbiodiv, booksubjectnaturalhistory
