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Skeletal reconstructions of A-B, E-F, Alcovasaurus longispinus with most of the known bones in white (except not all vertebrae could be placed) and C-D, Stegosaurus stenops (courtesy of G. paUl) in right lateral (A, C, E, F) and dorsal views (B, D). Note the proportionally shorter tail in Alcovasaurus (A, B cf. C, D) which was an adaptation to counter torque imposed by the long moment arm of the elongate caudal spines. E-F, skeleton supposedly based on illustrated bones, E, by T. Ford (in olshevsky & Ford 1995) and F, by Ulansky (2014c). Scale lines = 1 m.  

Skeletal reconstructions of A-B, E-F, Alcovasaurus longispinus with most of the known bones in white (except not all vertebrae could be placed) and C-D, Stegosaurus stenops (courtesy of G. paUl) in right lateral (A, C, E, F) and dorsal views (B, D). Note the proportionally shorter tail in Alcovasaurus (A, B cf. C, D) which was an adaptation to counter torque imposed by the long moment arm of the elongate caudal spines. E-F, skeleton supposedly based on illustrated bones, E, by T. Ford (in olshevsky & Ford 1995) and F, by Ulansky (2014c). Scale lines = 1 m.  

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The plated dinosaur Stegosaurus longispinus came from the Morrison Formation (Upper Jurassic) near Alcova, Wyoming, USA. Only the femur and plaster casts of the posterior pair of long dermal tail spines survived destructive water damage in the 1920s. This surviving material and archival photographs showing the bones in the quarry and as exhibited a...

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... "the neural arches of all 42 available vertebrae are missing or incomplete, intimating incidentally that despite its size the in- dividual was a juvenile in which the arches were in- completely fused to the centra." Ulansky (2014c) also restored the vertebrae, including cervicals, and noted that the lack of fusion indicated a juvenile individual (Fig. 9F). However, as noted for the dorsal and caudal vertebrae below, Gilmore (1914) gave some informa- tion on the neural arches, many of which were present on the vertebrae as exhibited (Figs. 2A-D, 4A, B), and the fusion to their respective centra indicates that this was not an immature individual. Cervical vertebra: A neck vertebra (cv, ...
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... Fig. 4D), definitely belonged to the holotype skeleton because no other animal occurred in the quarry (reed in Gilmore, 1914). This referral is confirmed by the form of the row of 27 caudal vertebrae ( Fig. 2A), all of which bore a prominent transverse process (Fig. 4A, B, 9A) that totally disappears by caudal 17 or 18 in Stegosaurus stenops ( Fig. 9C; USNM V 4934; Gilmore 1914) and is represented by a nubbin on caudal 20 in Hesperosaurus mjosi ). The row of 27 caudals also supports the view that the series of 10 vertebrae were distal caudals rather than mid- caudals (see Galton 2010: 195), especially as the four figured caudals match specific distal caudals in the row (Fig. 4B, C). ...
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... that enhanced the effectiveness of the tail spines as weapons (Galton 2010), a role demonstrated for the distal tail spines of Stegosaurus ( Mcwhinney et al. 2001;Carpenter et al. 2005) and Kentrosaurus (Mallison 2011a). The shortening of the lengths of the centra (Fig. 4C, 9A, B) would result in a proportionally shorter tail than in S. stenops (Fig. 9C, D) and further enhancement, even if no vertebrae were lost as in Kentrosaurus with ~43 caudals (Fig. ...
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... Gilmore (1914: 111) lists "portion of one pu- bis" with no further comments. One view in the quarry (Fig. 1B, C) shows the anterior process, the acetabular region and the base of the posterior process of the left pubis. The anterior process was long and slender (but slightly exaggerated by dorso-ventral foreshortening) as in Stegosaurus stenops (Fig. 9C), S. ungulatus (Gilm- ore 1914, figs. 23, 42, 43) and Hesperosaurus mjosi fig. ...
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... fig. 66.1-3). This pair are shown in several views (Fig. 8A-J) and the anterior spine as preserved in the quarry (Fig. 8K). In addition, the distance of the anterior spine to the posterior spine is believed to reflect their position relative to each other (Fig. 1E). If true, then the spine pairs are farther apart than they are in S. stenops (Fig. ...
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... & Ford (1993, fig. 22, 1995, fig. 32; 12) with the anterior pair based on the shorter spine as preserved and the posterior pair on the longer, both of which are incorrectly reconstructed too long compared to the femur (also case for Fig. 9E). Gilmore (1914: 112) noted that the "lower ends of the anterior [actually posterior] pair are rugosely roughened with weakly developed asymmetrically placed longitudinal keels [Figs. 1E, 8A-J]; the poste- rior [actually anterior] pair is smooth and without keel" which agrees with the incomplete left anterior spine as exposed in the ...
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... Natronasaurus and other nomina dubia of Ulansky (2014b) Ulansky (2014a-c) has used the name Natronasaurus tion of UW 20503 was based on Gilmore (1914: 111-3) and olshevsky & Ford (1993) plus additional compari- sons, mostly with Kentrosaurus and Hesperosaurus. The reconstruction (Fig. 9F) by Ulansky (2014c, fig. on p. 12) of Stegosaurus longispinus based on GreG paUl's (e.g. 2010) rendition of Kentrosaurus, includes the pre- viously illustrated femur, ischium, four out of 10 distal caudal centra and two distal tail spines (see Gilmore 1914: 111-3, figs. 60A, 66-68, pl. 25, fig. 4). The other 32 vertebrae and several ...
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... illustrated femur, ischium, four out of 10 distal caudal centra and two distal tail spines (see Gilmore 1914: 111-3, figs. 60A, 66-68, pl. 25, fig. 4). The other 32 vertebrae and several dorsal ribs, although mentioned by Gilmore (1914), were never illustrated and the fig- ures of these bones in Ulansky (2014c, fig. on p. 12) are hypothetical (Fig. 9F). He even notes that, judging from the proportions of the femur and the vertebral column, the back part of the body of UW 20503 was strongly raised above the ground (Fig. 9F). However, without knowing the length of the forelimbs, there is no justification for this statement. Finally, Ulansky's restoration of the vertebral column (Fig. ...
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... and several dorsal ribs, although mentioned by Gilmore (1914), were never illustrated and the fig- ures of these bones in Ulansky (2014c, fig. on p. 12) are hypothetical (Fig. 9F). He even notes that, judging from the proportions of the femur and the vertebral column, the back part of the body of UW 20503 was strongly raised above the ground (Fig. 9F). However, without knowing the length of the forelimbs, there is no justification for this statement. Finally, Ulansky's restoration of the vertebral column (Fig. 9F) does not agree with the vertebrae as illustrated in the photograph of the skeleton as exhibited (Figs. 2A-D, 4A, ...
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... (Fig. 9F). He even notes that, judging from the proportions of the femur and the vertebral column, the back part of the body of UW 20503 was strongly raised above the ground (Fig. 9F). However, without knowing the length of the forelimbs, there is no justification for this statement. Finally, Ulansky's restoration of the vertebral column (Fig. 9F) does not agree with the vertebrae as illustrated in the photograph of the skeleton as exhibited (Figs. 2A-D, 4A, ...

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