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Anchisaurus polyzelus
Taxonomy
Megadactylus polyzelus was named by Hitchcock (1865). It is a 3D body fossil. Its type locality is Springfield Armory, which is in a Hettangian/Sinemurian terrestrial sandstone in the Portland Formation of Massachusetts. It is the type species of Anchisaurus, Amphisaurus, Megadactylus.
It was recombined as Amphisaurus polyzelus by Marsh (1882); it was recombined as Thecodontosaurus polyzelus by Huene (1906), Huene (1914), Huene (1914), Huene (1926), Kuhn (1939) and Huene (1940); it was recombined as Anchisaurus polyzelus by Marsh (1885), Marsh (1896), Nopcsa (1901), Hay (1902), Hay (1910), Lull (1912), Lull (1915), Lull (1917), Hay (1930), Lull (1953), Steel (1970), Galton (1971), Galton (1973), Galton (1976), Galton and Cluver (1976), Attridge et al. (1985), Fedak (2003), Galton and Upchurch (2004), Weishampel (2006), Fedak and Galton (2007), Upchurch et al. (2007), Galton (2007), Barrett et al. (2007), Smith and Pol (2007), Nesbitt et al. (2007), Yates (2010), Tweet and Santucci (2011) and Apaldetti et al. (2011).
It was recombined as Amphisaurus polyzelus by Marsh (1882); it was recombined as Thecodontosaurus polyzelus by Huene (1906), Huene (1914), Huene (1914), Huene (1926), Kuhn (1939) and Huene (1940); it was recombined as Anchisaurus polyzelus by Marsh (1885), Marsh (1896), Nopcsa (1901), Hay (1902), Hay (1910), Lull (1912), Lull (1915), Lull (1917), Hay (1930), Lull (1953), Steel (1970), Galton (1971), Galton (1973), Galton (1976), Galton and Cluver (1976), Attridge et al. (1985), Fedak (2003), Galton and Upchurch (2004), Weishampel (2006), Fedak and Galton (2007), Upchurch et al. (2007), Galton (2007), Barrett et al. (2007), Smith and Pol (2007), Nesbitt et al. (2007), Yates (2010), Tweet and Santucci (2011) and Apaldetti et al. (2011).
Synonyms
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Synonymy list
Year | Name and author |
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1865 | Megadactylus polyzelus Hitchcock p. 40 |
1870 | Megadactylus polyzelus Cope pp. 122-E–122-F |
1882 | Amphisaurus polyzelus Marsh |
1882 | Megadactylus polyzelus Quenstedt p. 130 |
1885 | Anchisaurus polyzelus Marsh |
1889 | Anchisaurus major Marsh pp. 331-332 fig. 1 |
1890 | Anchisaurus major Zittel p. 730 |
1891 | Ammosaurus major Marsh p. 267 |
1891 | Anchisaurus colurus Marsh pp. 267-268 |
1892 | Anchisaurus solus Marsh p. 545 |
1896 | Anchisaurus colurus Gaudry p. 94 |
1896 | Anchisaurus polyzelus Marsh pp. 147-148 |
1896 | Ammosaurus major Marsh p. 148 |
1896 | Anchisaurus colurus Marsh p. 150 |
1896 | Anchisaurus solus Marsh p. 151 |
1898 | Megadactylus polyzelus Hitchcock p. 405 |
1898 | Anchisaurus colurus Woodward p. 197 |
1901 | Anchisaurus coelurus Gadow p. 421 |
1901 | Ammosaurus major Nopcsa p. 196 |
1901 | Anchisaurus colurus Nopcsa p. 196 |
1901 | Anchisaurus polyzelus Nopcsa p. 196 |
1901 | Anchisaurus solus Nopcsa p. 196 |
1902 | Ammosaurus major Hay p. 491 |
1902 | Anchisaurus colurus Hay p. 491 |
1902 | Anchisaurus polyzelus Hay p. 491 |
1902 | Anchisaurus solus Hay p. 491 |
1902 | Anchisaurus colurus Mansel-Pleydell p. lxxix |
1904 | Anchisaurus colurus Lull p. 470 |
1906 | Thecodontosaurus polyzelus Huene |
1908 | Anchisaurus colurus Abel p. 210 |
1910 | Anchisaurus colurus Hay p. 12 |
1910 | Anchisaurus polyzelus Hay p. 19 |
1910 | Anchisaurus colurus Versluys p. 205 |
1911 | Anchisaurus major von Zittel p. 280 |
1912 | Ammosaurus major Lull p. 411 |
1912 | Anchisaurus colurus Lull p. 411 |
1912 | Anchisaurus polyzelus Lull p. 411 |
1912 | Anchisaurus solus Lull p. 411 |
1914 | Ammosaurus major Huene p. 13 |
1914 | Anchisaurus colurus Huene p. 13 |
1914 | Anchisaurus solus Huene p. 13 |
1914 | Thecodontosaurus polyzelus Huene p. 13 |
1914 | Anchisaurus colurus Huene p. 69 |
1914 | Ammosaurus major Huene p. 74 |
1914 | Thecodontosaurus polyzelus Huene p. 75 |
1914 | Anchisaurus colurus Huene p. 156 |
1915 | Anchisaurus polyzelus Lull p. 119 |
1915 | Anchisaurus colurus Lull p. 130 |
1915 | Anchisaurus solus Lull p. 144 |
1915 | Ammosaurus major Lull pp. 148-149 |
1917 | Ammosaurus major Lull p. 111 |
1917 | Anchisaurus colurus Lull p. 111 |
1917 | Anchisaurus polyzelus Lull p. 111 |
1917 | Anchisaurus solus Lull p. 111 |
1920 | Anchisaurus solus Van Hoepen p. 92 |
1922 | Anchisaurus coelurus Case p. 80 |
1926 | Anchisaurus colurus Huene p. 6 |
1926 | Anchisaurus solus Huene p. 6 |
1926 | Thecodontosaurus polyzelus Huene p. 6 |
1928 | Anchisaurus major Perrier p. 3087 |
1930 | Anchisaurus polyzelus Hay p. 170 |
1930 | Ammosaurus major Hay p. 171 |
1930 | Anchisaurus colurus Hay p. 171 |
1930 | Anchisaurus solus Hay p. 171 |
1932 | Ammosaurus solus Huene |
1932 | Yaleosaurus colurus Huene pp. 119-120 |
1939 | Ammosaurus major Kuhn p. 33 |
1939 | Ammosaurus solus Kuhn p. 33 |
1939 | Thecodontosaurus polyzelus Kuhn p. 61 |
1939 | Yaleosaurus colurus Kuhn p. 63 |
1940 | Thecodontosaurus polyzelus Huene p. 37 |
1941 | Yaleosaurus colurus Huene p. 141 |
1941 | Yaleosaurus colurus Young p. 206 |
1952 | Yaleosaurus colurus Bock p. 405 |
1953 | Anchisaurus polyzelus Lull p. 99 |
1953 | Yaleosaurus colurus Lull p. 107 |
1953 | Anchisaurus solus Lull p. 120 |
1953 | Ammosaurus major Lull pp. 124-125 |
1958 | Ammosaurus major Kuhn p. 22 |
1958 | Yaleosaurus solus Kuhn p. 22 |
1964 | Ammosaurus major Tatarinov p. 530 |
1964 | Anchisaurus colurus Tatarinov p. 541 |
1967 | Ammosaurus major Charig p. 713 |
1967 | Ammosaurus solus Charig p. 713 |
1970 | Ammosaurus major Demathieu p. 153 |
1970 | Yaleosaurus colurus Demathieu p. 153 |
1970 | Ammosaurus major Steel p. 48 |
1970 | Ammosaurus solus Steel p. 48 |
1970 | Anchisaurus polyzelus Steel p. 48 |
1970 | Yaleosaurus colurus Steel p. 52 |
1971 | Anchisaurus polyzelus Galton p. 782 |
1973 | Ammosaurus major Benedetto |
1973 | Anchisaurus polyzelus Galton p. 247 |
1976 | Anchisaurus polyzelus Galton p. 88 |
1976 | Anchisaurus polyzelus Galton and Cluver p. 132 |
1976 | Ammosaurus major Galton and Cluver p. 143 |
1984 | Ammosaurus major Olsen and Galton p. 93 |
1985 | Ammosaurus major Attridge et al. p. 128 |
1985 | Anchisaurus polyzelus Attridge et al. p. 128 |
2003 | Anchisaurus polyzelus Fedak p. 49A |
2004 | Ammosaurus major Galton and Upchurch p. 234 |
2004 | Anchisaurus polyzelus Galton and Upchurch p. 234 |
2006 | Anchisaurus polyzelus Weishampel p. 138 |
2006 | Ammosaurus major Weishampel p. 139 |
2007 | Anchisaurus polyzelus Barrett et al. p. 321 |
2007 | Anchisaurus polyzelus Fedak and Galton p. 248 |
2007 | Anchisaurus polyzelus Galton p. 517 |
2007 | Anchisaurus polyzelus Nesbitt et al. p. 236 |
2007 | Anchisaurus polyzelus Smith and Pol p. 669 |
2007 | Ammosaurus major Upchurch et al. p. 75 |
2007 | Anchisaurus polyzelus Upchurch et al. p. 75 |
2009 | Ammosaurus major Bittencourt and Kellner p. 34 |
2010 | Anchisaurus polyzelus Yates p. 744 |
2011 | Anchisaurus polyzelus Apaldetti et al. p. 4 |
2011 | Anchisaurus polyzelus Tweet and Santucci p. 78 |
2011 | Ammosaurus major Tweet and Santucci p. 79 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Anchisaurus polyzelus Hitchcock 1865
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Invalid names: Ammosaurus major Marsh 1889 [synonym], Ammosaurus solus Marsh 1892 [synonym], Anchisaurus colurus Marsh 1891 [synonym]
Diagnosis
Reference | Diagnosis | |
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A. M. Yates 2010 | the following four characters remain as valid autapomorphies of Anchisaurus polyzelus.
1. A lateral pit on the lateral distal surface of the quadrate, just above the articular condyle (Yates 2004, fig. 4). This character is only observable in YPM 1883. 2. Foramen, or pit, opening ventrally on the base of the second sacral rib (Yates 2004, fig. 1). Originally described as a foramen, Sereno (2007) pointed out that it has not been demonstrated to penetrate deeply into the cortex of the bone. Nevertheless, the feature remains distinctive and it stands as a valid autapomorphy. It is visible in YPM 208 and YPM 1883. 3. A long, narrow preacetabular lobe of the ilium that is at least twice as long as it is high at its base (Galton 1976, fig. 19a, 26e). This character can be observed in YPM 208 and YPM 1883. 4. Dorsoventrally flattened ischial blades (mid-blade depth is less than 75 per cent of its width) with the long axis 7. of the cross-section set at a low angle to the horizontal (Text-fig. 2). This character is described above and replaces the ‘flat, coplanar ischial blades’ listed by Yates (2004, p. 7). This character can be observed in the holotype, AM 41⁄109, YPM 208 and YPM 209. In addition to these characters, a further three new autapomorphies can be added: 5. Transversely expanded ventral ramus of the postorbital (Yates 2004, fig. 8). This character was included by me in the list of derived character states that linked Anchisaurus to the sauropod clade, albeit with an ambiguous distribution. However, plesiomorphic, unexpanded postorbital ventral rami are now known to be present in sauropodomorphs closer to Sauropoda than Anchisaurus is (e.g. Melanorosaurus readi, Yates 2007b; Aardonyx celestae, Yates et al. 2010) and in basal sauropods (e.g. Tazoudasaurus naimi, Allain and Aquesbi 2008; Shunosaurus lii, Wilson and Sereno 1998). Thus, the ambiguity of this character is now clearly resolved in favour of an independant derivation in Anchisaurus and eusauropods more derived than Shunosaurus. Thus, the character is an autapomorphy for Anchisaurus convergent in derived Eusauropods. Of the Anchisaurus specimens the character is only visible in YPM 1883. Posterior dorsal centra approximately twice as long as the height of the centrum face (Galton 1976, fig. 15i, j). This autapomorphy was suggested by Sereno (2007) and can be observed in YPM 208, YPM 209 and YPM 1883. The proportions of dorsal centra do vary with size within Sauropodomorpha with smaller individuals tending to have more elongate dorsal centra (Yates 2007b, discussion of character 151 in Table 2). Nevertheless, similar sized posterior dorsal centra of Thecodontosaurus antiquus (BRSUG unnumbered; centrum length: 34 mm) and Massospondylus carinatus (BP ⁄ 1 ⁄ 5143; centrum length 42 mm) have a length : height ratio well under 2 (1.38 and 1.35, respectively), indicating that the proportions of Anchisaurus are unusual even for its small size and qualify as an autapomorphy. Slender first sacral rib with a base occupying less than half of the length of the first sacral centrum (Text-fig. 3). This novel character is discussed above. It can be observed in AM 41 ⁄ 109, YPM 208 and YPM 1883. |