Scale bar equal to 5 cm. The condyles are sub-equal in size, but the medial condyle is slightly eroded. By contrast with NHMUK PV R36730, the cervical ribs of Dacentrurus sp. Ns, neural spine; ri, ridge. Skeleton … The neural arch pedicle dorsal to the neural canal opening is gently concave transversely. In dorsal view, the diapophysis of S1 and the dorsal surfaces of the second, third and fourth sacral ribs are co-ossified to form a flat sacral yoke (Fig 31D). Scale bar equal to 5 cm. In anterior view, the rib shaft is straight and it tapers distally. This chapter discusses the skeletons of seven different species of marine mammals: the Florida manatee, the harbor seal, the California sea lion, the North Atlantic right whale, the bottlenose dolphin, the polar bear, and the sea otter. The humerus is similar to those of other stegosaurs including Dacentrurus sp. American Museum of Natural History, New York, U.S.A.; BYU, A subtle ridge arises from the lateral surface of the prezygapophysis and extends ventrally to merge with the anterior margin of the neural arch (Fig 29A). The ventrolaterally facing portions of the lateral surfaces of the centrum converge ventrally at an acute angle, forming a broad ventral keel (Fig 36E). At the very least it seems unwise to consider the height of the neural spines of the sacral vertebrae to be a diagnostic character at specific level until measurements can be provided to confirm Marsh’s reconstructions. At the proximal end a gently concave surface shaped like a right-angled triangle with the hypotenuse facing dorsomedially forms the articular surface of the olecranon process. It tapers posteriorly, is rugose, and is transversely and anteroposteriorly convex. In ventral view the articular surface has straight medial, anterior and lateral margins. The lateral surfaces of the neural arch are gently concave and meet dorsally to form a narrow flat ridge. Scale bar equal to 5 cm. The left diapophysis is teardrop-shaped with the apex pointing anteriorly in cross-section, while the right diapophysis is triangular with the apex pointing ventrally. The vertebrae are very poorly preserved. The remainder of the medial surface of the blade is flat or very gently concave. The posterior surface of the centrum is larger than the anterior surface. Scale bar equal to 5 cm. Centrum lengths, widths and heights represent the maximum measurement; neural canal width and height are measured posteriorly and represent the maximum measurement; neural arch height is measured vertically from the base of the neural canal to the top of the neural spine. The base of the right diapophysis is preserved, but the tip is reconstructed. (ML 433) and Huayangosaurus (ZDM T7001) do not extend as far posteriorly as in NHMUK PV R36730. The prezygapophyses are not as steeply inclined as they are in Cv3. This larger region comprises most of the proximal end in posterior view and has an inverted triangular outline. Department of Earth Science and Engineering, Imperial College, South Kensington Campus, London SW7 2AZ, United Kingdom, Affiliation In contrast to D1 and D2, the articular surfaces of the prezygapophyses are sub-rectangular with the long axis transverse, face dorsomedially, and are confluent on the midline so that the intraprezygapophyseal shelf is entirely absent (Fig 20F). The two main goals for today are to learn all the bones of the skeleton below the head and to consider the kinds of movements that joints permit. https://doi.org/10.1371/journal.pone.0138352.g028. On the left side, there is some evidence that the fibula articulated with the astragalus, although due to distortion of the distal ends of the fibulae and of the astragali, this is difficult to determine. [2] noted that the fusion of coracoids and scapulae varied among Stegosaurus individuals and was likely ontogenetic; it also appears to be variable in Kentrosaurus (fused in MB R.4802 and R.4803, unfused in R.4580). The ischium is very similar in all respects to those of other specimens of Stegosaurus (SCRM pers. The ribs are similar to Dr11 but are more gracile. A shallow fossa extends over the distal part of the anterior surface but has been accentuated by crushing. Description . When [2] was writing about Stegosaurus, only two other taxa, Dacentrurus (then referred to as Omosaurus) and Loricatosaurus (then known as ‘Stegosaurus priscus’) were known. Its anterior margin is anteriorly concave while its posterior margin is anteriorly convex (Fig 31A and 31B). A, anterior, B, posterior, C, left lateral, D, right lateral, E, ventral and F, dorsal view. In both anterior and posterior views, the neural canal is situated in a dorsoventrally elongate fossa that extends further dorsally than the neural canal opening (Fig 22A and 22B). A shallow concavity on the anterolateral surface of the neural arch is bounded posteriorly by the ACDL, anteriorly by the lateral margin of the neural canal, and dorsally by the prezygapophyses (Fig 13A). A, 1; B, 2; C, 3; D, 4; E, 5; F, 6; G, 7; H, 8; I, 10; J, 11; K, 13. Distally, the shaft expands again dorsoventrally to form a pubic symphysis (Fig 71) that is similar to those of Loricatosaurus (NHMUK R3167; [29]: fig 14V) and Kentrosaurus (MB R.4810). (ML 433) is concave upwards, and the centrum of Dacentrurus sp. The basal region, which comprises the basal one-fifth of the plate in lateral videw, is irregular and rugose. Cr, caudal rib; nc, neural canal; ns, neural spine; pozyg, postzygapophysis; przyg, prezygapophysis; ri, ridge. The lateral ginglymus is half the size of the medial ginglymus. In its proximal quarter the shaft narrows dorsoventrally and the middle portion of the shaft maintains the same width. Despite this reconstruction and deformation, enough detail is preserved to determine that Cv7 differs from the preceding vertebrae in the following ways. The left element, which is appressed to the left tibia (Fig 73), has been compressed and the proximal end has been rotated to lie in the same plane as the distal end, which is crushed. The rib shaft does not curve upward distally in contrast to the preceding cervicals, and the ventral margin of the entire rib describes a gentle sinusoidal curve. In lateral view the neural spine is sub-rectangular with straight anterior, dorsal and posterior margins (Fig 21D). https://doi.org/10.1371/journal.pone.0138352.g070. The centrum is almost amphiplatyan with only a slight depression in the ventral part of the anterior articular surface. This online quiz is called Cat-postcranial skeleton. The neural canal is arch-shaped in anterior and posterior view, rather than being teardrop-shaped, as it is in preceding vertebrae. Planes of Orientation The anterior articular facet is generally flat with a shallow central concavity; the posterior articular facet is gently concave (Fig 29A and 29B). The neural canal is round anteriorly and arch-shaped posteriorly. The medial part of the posterior articular surface extends further posteriorly than the lateral part. Van Valkenburgh , in her seminal work, found that the postcranial skeleton is a good indicator of locomotor ecology in both living and extinct carnivores. The shaft has a D-shaped cross-section with a flat anterior surface. It generally resembles Cv3, except for the following differences. 1), Huayangosaurus (ZDM T7001) and in Kentrosaurus (MB R.4787). https://doi.org/10.1371/journal.pone.0138352.g076. However, it appears to be identical in most respects to D6. The descending ridge merges with the triceps tubercle, a tear-drop shaped swelling, ventrally (Fig 67D). With the flat basal region held horizontally, the spine extends posterodorsolaterally at an angle of 70 degrees to the horizontal. The rib extends laterally and is fused to the medial surface of the acetabulum. This results in elevation of the postzygapophyses relative to those of Cv7, for example. The postzygapophyses extend posterodorsally from the posterior margin of the neural arch beyond the posterior articular facet for a distance approximately equal to half of their total length (Fig 7C and 7D). The midline of this structure extends into a short, sharp ridge that merges into the neural arch pedicel a short distance ventrally and does not reach the dorsal margin of the neural canal (Fig 21B). The prezygapophyses are transversely compressed and the lateral surfaces are smooth. 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