Theriosuchus undetermined
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publication ID |
https://doi.org/ 10.26879/514 |
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persistent identifier |
https://treatment.plazi.org/id/03CC1405-FFF0-FFC2-FC79-70EFFE4CEF6B |
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treatment provided by |
Felipe |
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scientific name |
Theriosuchus undetermined |
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Genus THERIOSUCHUS Owen, 1879 Species undetermined
Figure 5 View FIGURE 5
Referred material. 26 isolated teeth (7.12% of the sample = 365 teeth; MPZ 2014/478, 479, 480, 481, 482a, 482b, 482c and 821 through 841).
Description. The teeth show the typical autapomorphic characters observed in the genus Theriosuchus , with dentition that comprises labiolingually compressed low-crowned, pseudocaniniform and lanceolate-shaped teeth, with mesial and distal carinae. The teeth are laterally compressed with differences in size. The labial surface is convex and flatter than the lingual face, with a slight curvature towards the lingual area near the apex. This morphotype shows morphological variability that can be related to different dental positions observed in skulls and jaws with preserved teeth of Theriosuchus ( Owen, 1879; Brinkmann, 1992; Schwarz and Salisbury, 2005; Karl et al., 2006; Lauprasert et al., 2011; Martin et al., 2014). The teeth located in posterior positions of the tooth row ( Figure 5.1–2, 5 View FIGURE 5 ) are wider mesiodistally, highly laterally compressed, leaf-shaped and with a lower crown. The labial surfaces of these teeth are convex, and the lingual surfaces are flatter in the base and somewhat concave towards the apex. In addition, the radicular contour is slightly constricted, and the pulp cavity is completely flattened and elongated. By contrast, the teeth from anterior positions ( Figure 5.3–4 View FIGURE 5 ) are less laterally compressed, are lanceolate and have a considerably higher crown. They have mesial and distal carinae, but their torsion towards the lingual area is less pronounced. The pulp cavity is not as elongated or flattened, presenting an ellipsoidal morphology.
Remarks. Within this morphotype there exists great morphological variability associated with the enamel ornamentation and the presence or absence of true or false denticles on the carinae. Most teeth present longitudinal well-marked ridges, which are convergent in the central area of the tooth and diverge towards the carinae ( Figure 5.1 View FIGURE 5 , 3 View FIGURE 3 , 5 View FIGURE 5 ); others have fine anastomosed striae ( Figure 5.2 View FIGURE 5 ), and yet others have almost smooth enamel ( Figure 5.4 View FIGURE 5 ). This kind of tooth has been associated with insectivorous diets ( Buscalioni and Sanz, 1988). The presence, absence and size of the denticles on the carinae seem to be related with the convergence of enamel ridges or grooves towards the carinae (“false ziphodont” according to Prasad and Broin, 2002). The size of the denticles are proportional to the thickness of the ridges. However, teeth with nearly smooth enamel may also have denticles ( Figure 5.4 View FIGURE 5 ). The presence of leaf-shaped or lanceolate teeth is probably related to the tooth position in the dental series, but the variation in the enamel ornamentation may be due to the presence of several taxa or great intraspecific variability. This kind of dental morphology is typical of atoposaurids such as Theriosuchus .
| MPZ |
Museo Paleontologico de la Universidad de Zaragoza |
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