Bennett—Smallest Pteranodon


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Figure 6. Pteranodon and prey. (1) AMNH 5098, incomplete mandible of Pteranodon in dorsal view with mass of fish vertebrae preserved just behind symphysis. (2) Reconstruction of Pteranodon axial skeleton in left lateral view modified from Bennett (2001) and scaled to size of AMNH 5098 with skeletal reconstructions of fish (after Woodward, 1902–1912, fig. 12) scaled to sizes of the typical and largest fish vertebrae in the mass. Abbreviations: fv, mass of fish vertebrae, rr, right ramus of mandible; lr, left ramus of mandible; lfv, largest fish vertebra; and pm, posterior margin of symphyseal shelf. Scale bars are 3 and 15 cm, respectively.


second year-class exhibited parallel-fibered bone and lamellar bone with LAGs. The smaller of the two exhibited two closely spaced LAGs in the inner half of the cortex and a thick layer of parallel-fibered bone in the outer half of the cortex with a few primary osteons but lacking LAGs, and was interpreted as a late juvenile. The larger specimen in the second year-class, MTM V 2008.33.1, exhibited both primary and secondary osteons and three LAGs in the outer half of the cortex of the ulna, but only one in the femur, and was interpreted as an adult exhibiting skeletal maturity. The closely spaced LAGs in these specimens make it unlikely that every LAG is an annual line, but they may record successive stops and starts during a season of slowed growth. The largest specimen, BSP 1929.I.69, which exhibited parallel-fibered bone with primary osteons and 5–6 LAGs, was also interpreted as an adult. Prondvai et al. (2012) also discussed two specimens described by Padian et al. (2004), one similar in size and histology to the specimens in the small year-class, and RAM V97017/258, similar in size to MTMV 2008.33.1, which exhibited two widely spaced LAGs and fibrolamellar bone transitioning to lamellar bone with reduced vascularity in its


ulna, three LAGs in its femur, and four LAGs in its tibia. Prondvai et al. (2012) interpretedRAMV97017/258 as an adult. Based on their interpretation that MTM V 2008.33.1, RAM


V97017/258, and the larger BSP 1929.I.69 were all mature adults, Prondvai et al. (2012) concluded Bennett’s (1995) medium year- class was not a real ontogenetic stage because some mature adults occurred in it. However, Prondvai et al. (2012) did not use the terms juvenile and adult as Bennett (1995) did. Whereas Prondvai et al. (2012) interpreted MTM V 2008.33.1 as adult because of its histology and the fusion of bones, Bennett (1995) applied that term only to the largest most mature specimens and would have viewed the presence of an external fundamental system as the definitive indicator of histological adulthood just as Woodward et al. (2011) did in Alligator. Despite exhibiting relatively mature histology, MTM V 2008.33.1 is less mature than BSP 1929.I.69 because its jaws and teeth are less robust than those of BSP 1929.I.69, just as BSP 1929.I.69 is less mature than GPIT RE 7321 because its jaws and teeth of are less robust than those of GPITRE7321. In the end, Prondvai et al.’s (2012) histological information is consistent with and supports Bennett’s (1995, 1996) interpretation that the small


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