. Athlon : essays on palaeontology in honour of Loris Shano Russell. Paleontology. 40 new species of Ctenaspis Mode of Life Like several other Heterostraci, Ctenaspis possesses a rather flat dorsal shield and a deeply moulded ventral shield. This would scarcely seem to be an adaptation for benthonic life, yet with its deep, laterally compressed body and powerful tail it may have been not unsuccessful among the benthos. Ctenaspis lacked paired fins and the caudal fin was apparently deep and symmetrical, forming a locomotory organ of considerable power. The belly was rounded, broad anteriorly bu
. Athlon : essays on palaeontology in honour of Loris Shano Russell. Paleontology. 40 new species of Ctenaspis Mode of Life Like several other Heterostraci, Ctenaspis possesses a rather flat dorsal shield and a deeply moulded ventral shield. This would scarcely seem to be an adaptation for benthonic life, yet with its deep, laterally compressed body and powerful tail it may have been not unsuccessful among the benthos. Ctenaspis lacked paired fins and the caudal fin was apparently deep and symmetrical, forming a locomotory organ of considerable power. The belly was rounded, broad anteriorly but narrowing towards the hind end between the high cornual areas. The entire body was thus either rather fusiform or tadpole-like and can be visualised as remaining fairly stable while facing into a current. What, however, prevented it from toppling over sideways when at rest? The stout tail fin may have been directed to one side or the other as a prop. Although it lacked the large ventral lobe of, say, the pteraspids, it would have been sufficiently strong perhaps to prevent the body from tilting side- ways. Very possibly, however, the animal spent much of its time with the ventral shield, trunk and tail at least partially buried in sediment (Fig. 8). Only the mouth, eyes and flat back would be level with the water-sediment interface. In this way the animal would be supported on an "even keel" and would, especially in a coarse. Fig. 8 Ctenaspis. Restoration of carapace and scaled body and tail. Scale = 10 mm. a. Dorsal aspect, about natural size. b. Lateral aspect about natural size. c. Anterior aspect about natural size. d. Possible resting position with greater part of body buried in 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 Churcher, C. S. , 1928-; Russell, Loris Shano, 1904-; R
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