Hyperodapedon sp.
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publication ID |
https://doi.org/ 10.4202/app.00074.2014 |
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persistent identifier |
https://treatment.plazi.org/id/03B73024-FFDE-FF9C-6E5E-FE55FE87C19F |
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treatment provided by |
Felipe |
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scientific name |
Hyperodapedon sp. |
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Figs. 1D View Fig , 2 View Fig .
Material.—UFRGS-PV-0247-T, rib; UFRGS-PV-0247-T, UFRGS-PV-0293-T, tibia; UFRGS-PV-0247-T, humerus; UFRGS-PV-1217-T, radius; UFRGS-PV-0271-T, femur;- from Santa Maria Supersequence, Santa Maria 2 Sequence, Rio Grande do Sul, Brazil, Upper Triassic.
Description.— Rib (UFRGS-PV-0247-T): The rib ( Fig. 1D View Fig ) has a small medullary cavity surrounded by a relatively thick cortex. The secondary remodeling in the perimedullary region is extensive, with large resorption cavities. Vascular canals are numerous and arranged as longitudinally-oriented secondary osteons, mainly in the innermost cortex. The primary bone tissue consists of a parallel-fibred bone matrix with highly organized globular osteocyte lacunae. Canaliculi are extensive and radiate out in all directions from the osteocyte lacunae. Toward the periphery, the vascular canals decrease in abundance and tend to be arranged in circular rows. Two growth marks are seen in the outer cortex.
Tibia (UFRGS-PV-0247-T):The tibia ( Fig. 2A View Fig 1 View Fig ) has a large medullary cavity surrounded by a narrow cortex with some secondary remodeling in the perimedullary region. The cortex is highly vascularized by longitudinal primary and secondary osteons, without decreasing in size and abundance toward the periosteal surface. In some areas, the vascular canals are arranged as circular rows with anastomoses. The osteocyte lacunae in the innermost cortex are globular and arranged randomly around the vascular canals, indicating a fibrolamellar complex. The tissue changes toward the periosteal surface into parallel-fibred bone and the osteocyte lacunae become more organized, indicating a slight decrease in growth rate. One annulus interrupts the cortex near the periosteal surface.
UFRGS-PV-0293-T: The tibia ( Fig. 2C View Fig ) has a relatively narrow cortex surrounding a large medullary cavity.Secondary remodeling is extensive in the perimedullary region and extends to the mid-cortex. The cortex is moderately vascularized and contains mostly longitudinally-oriented primary osteons, with a decrease in vascularization toward the periphery. The osteocyte lacunae are abundant and globular, and arranged haphazardly around the primary osteons, indicating a fibrolamellar complex. However, toward the periphery, the osteocyte lacunae become more organized, in a parallel arrangement. Canaliculi are extensive and radiate out in all directions from the osteocyte lacunae. Two growth marks are present, one in the mid- and another in the outer cortex.
Humerus (UFRGS-PV-0247-T): The humerus ( Fig. 2A 2 View Fig ) shows extensive secondary remodeling, with large resorption cavities in the perimedullary region. This region contains globular osteocyte lacunae haphazardly distributed around the vascular canals, mostly primary osteons organized in a plexiform arrangement, indicating a fibrolamellar complex. Toward the periphery the osteocyte lacunae tend to be more organized and the primary bone tissue changes to parallel-fibred bone with the vascular canals arranged as longitudinal primary osteons. Canaliculi are extensive and radiate out in all directions from the osteocyte lacunae. One annulus is present in the mid-cortex.
MMACR-PV-018: The humerus ( Fig. 2D View Fig ) has a narrow cortex and a large medullary cavity. Secondary remodeling is extensive and large resorption cavities occur in the perimedullary region, extending periosteally. The narrow cortex is not well preserved, having suffered some diagenetic alteration. The cortex is highly vascularized and mostly contains primary osteons oriented longitudinally and arranged in circular rows. Osteocyte lacunae are abundant and globular, arranged haphazardly around the primary osteons, indicating a fibrolamellar complex in the perimedullary region. Toward the periphery, the osteocyte lacunae become more flattened and organized and are arranged parallel to one another, suggesting a change from fibrolamellar to parallel-fibred bone. One growth mark is present in the mid-cortex.
UFRGS-PV-0408-T: The humerus ( Fig. 2E View Fig ) has a relatively narrow cortex that surrounds a large medullary cavity. In the perimedullary region resorption cavities are extensive and extend to the outer cortex. The cortex is sligthy vascularized with longitudinally-oriented primary and secondary osteons. The osteocyte lacunae are mostly flattened and organized parallel to one another. These features indicate the presence of parallel-fibred bone. Four to five closely spaced growth marks are observed near to the outer cortex, which indicates a decrease in growth rate. The presence of EFS at the periosteal surface of the cortex indicates that UFRGS- PV-0408-T, had reached somatic maturity.
Radius (UFRGS-PV-1217-T): Secondary remodeling is not extensive in the radius ( Fig. 2B View Fig ). The primary bone tissue consists of fibrolamellar bone comprising a wovenfibred matrix with abundant longitudinal and radial primary osteons. The osteocyte lacunae are abundant and globular, distributed haphazardly around the primary osteons. There is no decrease in their size or abundance toward the periphery. Canaliculi are extensive and radiate out in all directions from the osteocyte lacunae. Growth marks are absent.
Femur (UFRGS-PV-0271-T): The femur is diagenetically modified, particularly in the inner and mid-cortex. The cortex is narrow with some secondary remodeling and has vascular canals arranged as longitudinally-oriented primary and secondary osteons, with a decrease in vascularization toward the periphery. The globular osteocyte lacunae are haphazardly distributed around the vascular canals, in a pattern compatible with that of a fibrolamellar complex. Growth marks are absent.
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