Camptosaurus dispar Marsh, 1879

Mcdonald, Andrew T., 2011, The taxonomy of species assigned to Camptosaurus (Dinosauria: Ornithopoda), Zootaxa 2783, pp. 52-68 : 56

Camptosaurus dispar Marsh, 1879

1879 Camptonotus dispar Marsh , p. 501. 1885 Camptosaurus dispar Marsh , p. 169. 1894 Camptosaurus medius Marsh , p. 85. 1894 Camptosaurus nanus Marsh , p. 85.

1909 Camptosaurus browni Gilmore , p. 295

Holotype. YPM 1877, partial postcranium from Quarry 13.

Paratype. YPM 1878, partial postcranium from Quarry 13.

Referred material. Disarticulated cranial and postcranial material in USNM and YPM collections, representing at least 15 additional individuals from Quarry 13 ( Gilmore 1909; Foster 2003). YPM PU14553, a partial skeleton from Cleveland-Lloyd Dinosaur Quarry.

Locality and horizon of USNM and YPM Quarry 13 specimens. Quarry 13 at Como Bluff, Albany County, Wyoming; Salt Wash Member of the Morrison Formation, Kimmeridgian ( Kowallis et al. 1998; Carpenter & Wilson 2008).

Locality and horizon of YPM PU14553. Cleveland-Lloyd Dinosaur Quarry, Emery County, Utah; Brushy Basin Member of the Morrison Formation, lower–middle Tithonian ( Kowallis et al. 1998).

Generic diagnosis. As for the species by monotypy.

Specific diagnosis. Basal ankylopollexian diagnosed by the following unique combination of characters: scapula with triangular acromion process, straight dorsal margin of scapula ( Fig. 3 A), straight dorsal margin of ilium, dorsal margin of ilium thickens mediolaterally towards M. iliocaudalis platform, postacetabular process of ilium tapers to a point with break in slope along dorsal margin ( Fig. 4 ), prepubic process unexpanded and concave along its dorsal margin ( Fig. 5 ), distal end of ischium forms rounded expansion.

Remarks. Camptosaurus dispar was originally named Camptonotus dispar by Marsh (1879) based upon material from Quarry 13, but was renamed Camptosaurus dispar ( Marsh 1885) because the name Camptonotus had already been coined by Uhler (1864:548) for a genus of gryllacridid cricket ( Capinera et al. 2004). The additional species C. medius ( Marsh 1894) , C. nanus ( Marsh 1894) , and C. browni ( Gilmore 1909) were subsequently named based upon material from Quarry 13, demarcated primarily by body size. However, this study follows Galton & Powell (1980), Norman (2004), and Carpenter & Wilson (2008) in regarding all the Camptosaurus material from Quarry 13 as representing a single species, C. dispar .

The ilium of YPM PU14553 is identical to those of C. dispar from Quarry 13 (e.g., USNM 5473, 5818, 5959, 7631; YPM 1877, 1880, 8619, 8622), most importantly in having a straight dorsal margin, differing from the convex dorsal margins exhibited by ilia of Uteodon aphanoecetes and Cumnoria prestwichii ( Fig. 4 ; Figs. 6 A, F). The other preserved elements (dentary, pubis, and ischium) are also quite similar to those of Quarry 13 specimens (e.g., YPM 1886, YPM 7334, and USNM 4697, respectively). YPM PU14553 is thus referred to Camptosaurus dispar . This referral is based upon shared morphologies only; provenance is not taken into consideration. The coding of Camptosaurus dispar for the phylogenetic analysis was based almost entirely upon the material from Quarry 13; the predentary of YPM PU14553 was used to code C. dispar for characters pertaining to that element because no predentaries are present in the Quarry 13 collections.

Figures

FIGURE 3. (A) USNM 4282, left scapula of Camptosaurus dispar in lateral view; (B) CM 11337, cranial end of the right scapula of Uteodon aphanoecetes in lateral view; (C) CM 11337, left scapula of Uteodon aphanoecetes in lateral view; (D) OXFUM J. 3303, right scapula of Cumnoria prestwichii in lateral view. Abbreviations: cap, convex cranial margin of the acromion process; tap, triangular acromion process. Scale bar in A equals 10 cm; scale bar in B equals 5 cm.

FIGURE 4. Ilia of Camptosaurus dispar in lateral view. (A) right ilium of YPM 1877 (holotype) from Quarry 13; (B) right ilium of YPM 8622 from Quarry 13; (C) left ilium of USNM 5473 from Quarry 13; (D) left ilium of YPM PU 14553 from Cleveland-Lloyd Dinosaur Quarry. Abbreviations: mlt, mediolateral thickening; pas, break in slope along dorsal margin of postacetabular process. Images in A, B, and D are copyright YPM. Scale bar equals 10 cm.

FIGURE 5. YPM 7334, right pubis of Camptosaurus dispar from Quarry 13 in lateral view. Abbreviations: pop, postpubic process; prp, prepubic process. Image is copyright YPM. Scale bar equals 10 cm.

FIGURE 6. Left ilium of CM 11337 (holotype of Uteodon aphanoecetes) in (A) ventrolateral view showing the convex dorsal margin, (B) lateral view, (C), caudal view. Sacrum and ilia of CM 11337 in (D) dorsal view. Right ilium of CM 11337 in (E) lateral view. Right ilium of OXFUM J. 3303 (holotype of Cumnoria prestwichii) in (F) lateral view. Abbreviations: dmi, dorsal margin of ilium; mlt, mediolateral thickening; pas, break in slope along dorsal margin of postacetabular process.