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Home , Amphicoelias, Brachiosauridae, Camarasauridae, Coracoid, Diplodocidae, Supersaurus

Great Basin Naturalist

Volume 47 Number 4 Article 19

10-31-1987

New brachiosaur material from the Late of Utah and Colorado

James A. Jensen Provo, Utah

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Recommended Citation Jensen, James A. (1987) "New brachiosaur material from the of Utah and Colorado," Great Basin Naturalist: Vol. 47 : No. 4 , Article 19. Available at: https://scholarsarchive.byu.edu/gbn/vol47/iss4/19

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. NEW BRACHIOSAUR MATERIAL FROM THE LATE JURASSIC OF UTAH AND COLORADO

James A. Jensen'

Abstract —Little is known about the , which includes some of the largest known sauropods, such as the , discovered in western Colorado by Elmer S. Riggs in 1900. Additional diagnostic material, previously unknown in the western hemisphere, is reported from three comparatively recent quarries: the Jensen/ Jensen Quarry in eastern Utah and the Dry Mesa and Potter Creek quarries on the Uncompahgre Upwarp in western Colorado. An unknown, well-preserved, articulated sauropod atlas/axis, seven , and an interesting flora were associated with the Potter Creek Quarry brachiosaur material. Taphonomic factors in that quarry are noted. The Jensen/Jensen and Dry Mesa deposits occur in basal sediments of the Brushy Basin Member of the , and the Potter Creek Quarry in an intermediate section of that member.

No complete, articulated skeleton of the A decade later a second discovery of bra- sauropod genus Brachiosaurus has been re- chiosaur bones was collected by a German ported from . However, an in- paleontologist, Janensch, in Tendaguru, Tan- complete skeleton was collected in Colorado zania, formerly East . He recovered a in 1901, and disarticulated bones of the genus fairly complete skeleton that he named B. have been found in at least four other locali- brancai (Janensch 1914); the restored skele- ties. Elements described here, not previously ton is now mounted in the Museum fiir reported from the western hemisphere, in- Naturkunde in East Berlin, East Germany. clude a partial , a distal cervical verte- Subsequent work by British expeditions, and bra, a radius, a metacarpal, and a . possibly other European institutions, recov- The radius, metacarpal, and humerus appear ered other brachiosaur materials from Tanza- to represent a novel but will not be nia, but for more than 80 no additional described here as such. brachiosaur remains were scientifically re- In 1900 the -species of the genus Bra- ported from the western hemisphere. chiosaurus was collected by Elmer S. Riggs, Circa 1943 a brachiosaur skeleton in an ad- of the Field Columbian Museum, Chicago, vanced state of erosion was discovered on the who discovered a partial skeleton of this re- Uncompahgre Upwarp in western Colorado markable sauropod near Grand Junction, Col- by the late Daniel E. Jones and his wife, Vi- orado. This skeleton possessed the previously vian, of Delta, Colorado. The humerus (Figs. unknown feature of front legs equal in length 2B, 3A-D, 4B) was collected and donated to

to the rear (Fig. 1), which elevated the base of the U.S. National Museum in Washington, the neck and thorax far above any spinal incli- D.C., but was never described. The discov- nation previously reported in sauropods. ery site, approximately 70 km SSE of the

Riggs (1903) appropriately named it Bra- Riggs locality, was named the Potter Creek chiosaurus altithorax. He recovered approxi- Quarry. Its stratigraphic position is approxi- mately 20 bones, including seven articulated mately in the middle of the Brushy Basin presacral and two caudal vertebrae, a sacrum Member of the Morrison Formation. I and the right ilium, a left coracoid, right worked there two seasons (1971, 1975), col-

humerus, right femur (Fig. 1), and four ribs. lecting five disarticulated elements of a large The femur and humerus were greatly com- sauropod (? B. altithorax), bones of a second, pressed, with the distal end of the latter being smaller sauropod genus, and teeth of an un-

partially destroyed by surface erosion (Fig. 1). known theropod. The brachiosaur elements

This material is now preserved in the Field collected include part of the discovery Museum of Natural History, Chicago. humerus (Figs. 3E, 5A-D, 6B), a medial

'2821 North 700 East, Provo, Utah 84604.

592 JENSEN; New Material 593 Bi C

Fig. 1. A-D, F-H, elements of the type o( Brachiosaurns altithorax (from Riggs 1904): A, humerus, anterior view; proximal Ai, end; B, femur, anterior view; Bi, proximal end view; C, right ilium; D, fifth presacral ; E, Potter Creek Quarry brachiosaur, fourth or fifth presacral vertebra; F, thoracic rib head, anterior view; G, B. altithorax, thoracic rib head, mesio-anterior view; H, B. altithorax. lateral view of left coracoid. Scale: A-D, F-H, approximately 1/12 natural size.

dorsal vertebra (Figs. 3D, 4A-A3), an incom- vertebral series from the atlas/axis to the sev- plete left ilium (Fig. SA-A^), and a left radius enth cervical vertebra. This series was found and metacarpal (Figs. 3B, 5E-Ei). Materials intact but excavated in fragments by the Jones of the smaller, indeterminate sauropod in- and given to me. I was able to reassem- clude the broken fragments of an articulated ble an articulated atlas/axis and third cervical 594 Great Basin Naturalist Vol. 47, No. 4

i^ i^»fe iiT * Mm

Fig. 2. A, Jensen/Jensen Quarry: scapula with coracoid in foreground (the only existing illustration of these unprepared brachiosaur elements); worker in upper right corner is sawing around border of 9' brachiosaur rib; B, Potter Creek Quarry.

vertebra (Fig. lOA-E) from this broken mate- elements noted here are much too short and

rial because of its excellent preservation. A small for any described brachiosaurid. detailed study of some of this material is in In 1960 I discovered a dinosaur bone de- progress, but a preliminary examination re- posit in basal Brushy Basin Member sedi-

veals it to be from a mature sauropod. The ments of the Morrison Formation near October 1987 JENSEN: New Dinosaur Material 595

Fig. 3. Potter Creek Quarry brachiosaur: A-A2, left ilium (dorsal border, ischiadic peduncle restored); B, radius; C, metacarpal; D, fourth or fifth dorsal vertebra; E, left humerus. Abbreviations: dc, deltoid crest; ms, muscle fossa.

Jensen, Utah. This deposit (the Jensen/Jensen with the scapula does not appear to match the Quarry) is located south of the Green River, a coracoid of B. altithorax, the specific identity few miles from the Dinosaur National Monu- of the elements is presently in question. ment Quarry. Two years' work (1962, 1966) in When fully prepared, the material may repre- this quarry (Figs. 11, 13) produced several sent an undescribed species; but an in- brachiosaur elements including a rib 2. 75 m (9 sufficient number of elements duplicating ft) long (Fig. 6B), a distal cervical vertebra, those of the type-species presently precludes the proximal half of a scapula, and a coracoid. such a determination. Additional, well- Many worthless slivers and fragments of shat- preserved brachiosaur material, cited in the tered brachiosaur cervical vertebrae were en- Uncompahgre fauna (Jensen 1985), is de- countered. Because the coracoid associated scribed here from the Potter Creek Quarry. 596 Great Basin Naturalist Vol. 47, No. 4

Fig. 4. Dorsal vertebrae: A-A3, Potter Creek Quarry brachiosaur, fourth or fifth dorsal vertebra, right lateral view; B-B2, Dystijlosaurus edivini, type (B), anterior (B,), posterior (B,), right lateral views, probably anterior dorsal; C, macintoshi, type posterior dorsal vertebra, 1.45 m tall, lett lateral view. October 1987 JENSEN; New Dinosaur Material 597

Fig. Potter 5. Creek Quarry: A-D, brachiosaur humerus. A, proximal end; B, mid-shaft section; C, detail of bulbous deltoid crest; D, anterior, distal end; E, metacarpal MC I, mesial view; Ej, same, lateral view. Abbreviations: dr, deltoid ridge; ms, muscle fossa/scar. 598 Great Basin Naturalist Vol. 47, No. 4

Fig. 6. A, referred to Ultra.saunis nuicintoshi. prone figure 6'.3" tall; B, Jensen/Jensen Quarry brachiosaur rib, Ultrasaunts scapulocoracoid. Potter Creek Quarry brachiosaur left humerus. All three elements cast in fiberglass resin. October 1987 JENSEN: New Dinosaur Material 599

y?fiL:^dl^

J I m

Fig. 7A-B. Reconstructed front limb with cast scapulocoracoid of Ultrasaurus macintoshi (figure 6'3" tall): A, mid-cervical vertebra, vivianae, anterior view (original seen in Fig. 8); B, same, left lateral view. Vertebra restored from original and cast in fiberglass resin.

This material is much better preserved than nosis (see Systematic ). that of the type of B. altithorax (Riggs 1903) In 1972 I opened a quarry near Dry Mesa and justifies some revision of the generic diag- (Dry Mesa Quarry) in basal Brushy Basin 600 Great Basin Naturalist Vol. 47, No. 4

poc

Fig. 8. A, Proximal end of brachiosaur femur, proximal end 5'6" in circumference, from Recapture Member of the Morrison Formation; B, Siipersatirus vivianae, right lateral view of mid-cervical vertebra; C, mid-cervical vertebra,

Supersaurus vivianae right lateral view (restoration seen in Fig. 7). Abbreviations: acx, anterior convexity; bns, bifurcate neural spine; idl, infradiagonal lamina; poc, posterior concavity; pp, parapophysis; prdl, prediapophysial lamina; prz, prezygapophysis; pz, postzygapophysis; sdl, supradiagonal lamina; tp, transverse process; vl, ventral lamina.

Member sediments on the NE monocline of related materials including bones of several the Uncompahgre Upwarp in western Colo- unusually large sauropods (Jensen 1985), rado. This quarry (Fig. 13) lies approximately some of which appear to be brachiosaurid. 20 km NW of the Potter Creek Quarry but is Among the large elements recovered was a (?) on a significantly lower horizon. A decade of mid-cervical vertebra more than 1 m in length

work in it produced many tons of dinosaur- (Figs. 7A-B, 8C), which, having a bifurcate October 1987 JENSEN: New Dinosaur Material 601

Fig. 9, Scapula (coracoid) profiles of eight sauropod genera: A, Haplocanthosaunis; B, Supersaurus vivianae; C,

Cetiosaunis; D, ; E. Cainarasaurus; F, ; G, Supersaurus; H, Brachiosaurus; I, Ultrasaurus. Not to scale. 602 Great Basin Naturalist Vol. 47, No. 4

/4 *

pp ax

Fig. 10. Potter Creek Quarry, unidentified sauropod atlas/axis with intercentrum third cervical vertebra: A, superior view; B, inferior view; C, anterior view; D, right lateral view; E, posterior view. Abbreviations: at, atlas; ax, axis; erf, cervical rib fragment; ctp, collapsed transverse process; dp, diapophysis; ira, incorrectly restored area (x x in dotted lines); n, neurapophysis; pp, parapophysis.

spine, was readily identifiable as unrelated to and, secondly, the fact that two unusually Brachiosaurus. Because of its huge size, how- large (Figs. 9B, 9G), found

ever, an error was made in referring it to in the same (Dry Mesa) quarry, were refer- Ultrasaurus macintoshi Jensen (1985), in the able to the . One of these (BYU Brachiosauridae. To mitigate this error, I here 5500, Fig. 9B) is the of Supersaurus remove the vertebra, BYU 5003, from Bra- vivianae Jensen (1985). A large rib (Figs. IF,

chiosauridae and provisionally refer it to the 8B), though broken into many sections, ap-

Diplodocidae. This referral is based on two pears to have been more than 3 m (over 10 ft) factors: principally, a bifurcate neural spine. long. October 1987 JENSEN: New Dinosaur Material 603

Fig. 11. Jensen/Jensen Quarry, 1966: A, Dinosaur National Monument Quarry; B, same quarry in 1986.

In 1979 a scapulocoracoid, 2.70 m (8' 10") readily referable to the Brachiosauridae (Fig. long (Figs. 6A-B, 91) was collected in the Dry 9H) and is the holotype of Ultrasaurus macin- Mesa Quarry. This scapula, BYU 5000, is toshi Jensen, 1985. 604 Great Basin Naturalist Vol. 47, No. 4

Fig. 12. Profiles of various sauropod femora: A, brachiosaurid. Recapture Creek Member, Morrison Formation; B, apatosaur; C, Diplodocus; D, unidentified. Dry Mesa Quarry. Abberviations: alam, alamosaur; amph, ; apato, apatosaur; brach, brachiosaur; camar, camarasaur; diplo, Diplodocus; haplo, haplocanthosaur. All scale bars equal 0.5 m.

In 1985 I found the proximal third of an rison Formation in Utah near the Arizona bor- extremely large sauropod femur (Figs. 8A, der. It is the largest bone I have ever seen; it is 12A) in a uranium miner's front yard in south- also the first dinosaur bone reported from the ern Utah. The head of this femur is 1.67 m Recapture Member of the Morrison Forma- (5 '6") in circumference and was collected from tion and is herein pictured in Figure 8A. The the Recapture Creek Member of the Mor- proximal end of a sauropod femur is generally October 1987 JENSEN: New Dinosaur Material 605

>A R / Z V N A

Fig. 13. Map of 26 quarries worked by the author in the and Jurassic of Utah and Colorado during a 20- period. Name ofquarry and year(s) worked, Hsted chronologically; 1, Jensen/Jensen, 1962, 1966; 2, Red Seeps, Easter, 1966; 3, North Horn, 1966; 4, Recapture, 1967, 1982; 5, Dominguez/Jones, 1967; 6, Park, 1968, 1977; 7, Singleton Flat, 1969; 8, Gilmore Gulley, 1969, 1980; 9, Kelvin, 1970; 10, Uravan, 1970; 11, East Fork Hadrosaur, 1971; 12, Potter Creek, 1971, 1975; 13, Gilmore Lizard, 1971; 14, Dr\- Mesa, 1972-1983; 15, Tracks, 1973; 16, Picnic Springs, 1973; 17, Navajo Hill, 1973; 18, Hinkle, 1973; 19, Dalton Well, 1975, 1978; 20, Calico Gulch, 1973, 1976; 21, Cedaredge Mosasaur, 1979; 22, Titanosaur, 1980; 23, Hummingbird, 1981; 24, Holly Hollow, 1982; 25, Faithful Smith, 1982; 26, Rotten Fuse, 1982. 606 Great Basin Naturalist Vol. 47, No. 4 not significantly diagnostic, but in profile height of the vertebra is comparatively (Fig. 12A) this specimen resembles the Upper greater than that of the type with a proportion Cretaceous Alamosauriis (Fig. 12 alam.) more of centrum length to total vertebral height of 3 than it does profiles of Jurassic sauropods (Fig. to 7, compared to a proportion of 3.7 to 7.2 in 12). In the latter group it bears the greatest the type (Riggs 1904). The supraprezygopo- resemblance to the profile of Brachiosaurus physeal laminae are not parallel, as in B. al- (Fig. 12 brach.) and is here referred to that tithorax, but conjoined midway up the neural family. spine, forming a robust pre spinal lamina that transversely increases in width dorsally (Figs. 3D, Both diapophyses are missing, leav- Systematic Paleontology 4Ai). ing the length of the transverse processes un- Suborder known. A moderately developed hyposphen- hypantrum articulation contrasts with the Infraorder unusually developed intervertebral articula- Brachiosauridae tions in B. altithorax. An elongate centrum has well-developed pleurocoels. The apex of Brachiosaurus Riggs 1903 the neural spine is expanded into a robust Revised generic diagnosis. —Humerus 90-degree, transverse, gablelike metapophy- and femur of subequal length; humerus with seal cap (Fig. 4Ai). The neural arch is con- deltoid crest located one-third of total shaft stricted around its base (Fig. 4A-Ai) rather length down from proximal end; neural arches than being anteroposteriorly long as in Ultra- moderately elevated, all neural spines single, sauriis Jensen, 1985 (Fig. 4C), or long and not bifid, increasing in height anteriorly from broad as in Dystylosaurus Jensen, 1985 (Fig. sacrum to mid-dorsal region, short transverse 4B-Bo). processes on first presacral vertebra increas- The inner and outer distal condyles of the ing in length on each vertebra to the mid-dor- humerus are anteriorly prominent (Fig. 5D). sal section, dorsal centra with well-developed The rugose crest of the deltoid ridge is bul- pleurocoels, hyposphene-hypantrum articu- bous, comparatively short (Fig. 5B-C), and lation well developed; height of first two pre- centered one-third of the total shaft length sacral vertebrae shorter than the preceding below the proximal end. A prominent, deep series, with length of centra short, length of muscle fossa with a transverse, crenulated, the third to seventh presacral centra equal to lower margin (Fig. 5A) occurs in the upper half the vertebra's total height, measured part of the broad, anterior valley, adjacent to from ventral border of anterior convexity to the deltoid ridge. spinal apex; dorsal rib heads pneumatic; A metacarpal (Fig. 5E-Ei), probably right, sacrum with five ilium-supporting vertebrae, MC III, has a laterally expanded distal end. width of sacrum approximately equal to The radius (Fig. 3B), with few distinguish- length, with short sacral spines and five co- ing features, is tentatively identified as the ossified centra; anterior caudal vertebrae with left. short neural spines, moderately developed The anterior iliac process is massive and caudal ribs, and no pleurocoels. shorter than that of B. altithorax. The dorso- Referred specimens. —BYU 9754: mid- posterior third of the ilium, including the is- dorsal vertebra, partial left ilium, left radius, chiadic peduncle, is missing and is conserva- one right metacarpal, left humerus, and vari- tively restored here after several Tendaguru ous rib sections, all associated. brachiosaur ilia in the British Museum (Natu- ral History) (Mcintosh 1980, personal com- Species Indeterminate munication). The pubic peduncle is long and Horizon and locality.—An intermediate thin, viewed laterally, forming a weak ante- horizon of the Brushy Basin Member, Mor- rior acetabular arch. rison Formation, Late Jurassic Period; Potter Discussion. —A deep muscle fossa with Creek Quarry, T49N, R12W, SW 1/4, Sec 5, a crenulated lower margin (Fig. 5A ms) occurs Montrose County, Colorado. on the humerus in the upper part of a broad marking Collector.—J. A. Jensen. valley adjacent to the deltoid ridge, Description.—Mid-dorsal vertebra. The the terminal insertion of a large adductor October 1987 JENSEN: New Dinosaur Material 607

cle. This may have been the "antero-superior occurrence as "isolated skeletal parts, " the muscle" identified in supre- Potter Creek faunal list includes at least three 7nus by Osborn and Mook (1921), or the M. families: two sauropodomorphs; Brachiosati- pectorahs, or an equivalent of the M. del- rus sp., and an unidentified smaller sauropod; toideus, said to terminate on or near the del- and an unusually large theropod, possibly toid ridge in ornithischian (Romer Torvosaunis Galton and Jensen (1979), or a 1927). This fossa is not known to be equally large allosaurid. Furthermore, the pattern of prominent in other sauropod genera. bone occurrence is associated and articu- The long, comparatively weak pubic pe- lated, rather than "isolated," as reported, and duncle of the ilium suggests the anterior end the locality produced elements of a well- of the ilia may have been rotated ventrally preserved flora consisting of various unde- around a transverse acetabular axis, similar to scribed reproductive structures. the 20-degree iliac rotation seen in the Taphonomy.—The huge brachiosaur ilium sauropod Cathetosaiirus leivisi Jensen (in was partially destroyed, broken diagonally press). In that genus a ventral rotation of the through its thickest section and separated anterior iliac processes placed a stronger, from the dorsoposterior section, which was well-buttressed section of the ilia above the never found. This damage was not the result head of the femur. This rotation, not reported of levee overwash, stream abrasion, large- in other sauropod genera, allowed C. lewisi to turbation, postburial pressure and elevate the anterior body, neck, front limbs, faulting, nor scavengers, since no teeth marks and thorax to a bipedal stance. A similar iliac were found in any of the bones. Also, the rotation in brachiosaurs would have compen- uncrushed, articulated, unidentified, smaller- sated for an elevated thorax due to their un- sauropod cervical series was found adjacent to usually long front limbs (Riggs 1903). In non- the broken ilium, undamaged by the force(s) bipedal sauropods, such as the Apatosauridae, partially destroying that huge element. The Diplodocidae, and , elevation ilium was apparently broken elsewhere, the of the anterior body would have obliged the parts separated, with only one being trans- weakest cross section of the pubic peduncle to ported to the site. Unusually strong hydraulic carry a major amount of body weight. pressure would have been required to move Unidentified sauropod. It is concluded such a heavy, irregular shape, but no evi- here that the atlas/axis and articulated third dence of high-energy fluvial activity was cervical vertebrae (Fig. 10) belong to an present in the surrounding sediments and unidentified sauropod. This determination is so no explanation of this enigma is readily strengthened by the allochthonous nature of apparent. the deposit in which three families were rep- When I first visited the locality, a consider- resented; however, only mild evidence of able amount of shattered dinosaur bone, obvi- strong, fluctuating currents, such as heavy ously belonging to a large individual, was ly- cross-bedded sands, grits, bone abrasion, and ing on the slope below the deposit. The Jones rip-up mudclasts, was encountered during ex- family informed me that more was present tensive excavations in the area. when they discovered the site many years An autochthonous deposit of dinosaur earlier. This lead to the conclusion that the bones usually contains the remains of one major portion of a brachiosaur skeleton was skeleton, representing the one-time death- present before erosion. site burial of an individual (Dodson et al. Flora.—Considerable material 1980), characteristically isolated from the dis- was present in an area adjacent to the quarry ruptive hydraulic forces of active channel en- horizon in the form of reproductive struc- vironments. Allochthonous deposits, on the tures. Cycadophyta seeds were common, other hand, are composed of disarticulated from the family Cycadales (Chandler 1966), parts of various collected by active on fragments of macrosporophyll, including hydraulic forces sweeping a drainage area the micropyle of fertile embryos. I collected during an indefinite, extended period of time. approximately one liter of these organs, as Correcting an earlier, inaccurate report on well as immature seeds of Behuninia joannei the Potter Creek fauna (Dodson et al. 1980), (Chandler 1966) and mature seeds of the which listed one and the pattern of bone Cycadophyta Jensensispermum redmondi 608 Great Basin Naturalist Vol. 47, No. 4

(Chandler 1966). Other reproductive struc- support that has enabled me to continue pub- tures included a cone of the gymnosperm lication of the results of 23 years of collecting Coniferales, family Taxodineae, Sequoia sp., new dinosaurs. seeds of the genus Carpolithus Linnaeus in- certae sedis (Chandler 1966), and many Literature Cited megasporophyll fragments. This fossil plant Chandler, M E 1966. Fruiting organs from the Mor- material, a faunal list, and the information on J rison Formation of Utah, USA. Bull. British Mu- taphonomy were available but not published seum (Natural History) Geology 12(4); 139-171. in the first taphonomic report on the quarry Dodson, PA K Behrensmeyer, R T Bakker, and] S (Dodson et al. 1980). McIntcsh 1980. Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Forma-

tion. Paleobiology 6(2): 208-232.

Acknowledgments Galton, P M , AND J A Jensen 1979. A new large theropod from the upper Jurassic of Colorado. The Daniel E. "Eddie" Jones family of Brigham Young Univ. Geol. Stud. 26(2): 1-12. Delta, Colorado, were responsible, circa Janensch, W 1915. Die wirbelsaule von Brachiosatirus brancai. Palaeontographica Supplement 7 Erste 1943, for the first new brachiosaur bones Reihe 3. found in the western hemisphere since the Jensen, J. A. 1985. Three new sauropod dinosaurs from discovery of the o(Brachiosaurus the Upper Jurassic of Colorado, and the Uncom- by E. S. Riggs in Colorado in 1900. Other pahgre fauna, a preliminary report. Great Basin brachiosaur bones described here, particu- Nat. 45(4): 697-720.

Osborn, H F , AND C. C. MooK. 1921. Camarasaurus, larly those from the dry Mesa Quarry, are also Amphicoelias , and other sauropods of Cope. the result of their extensive explorations on Mem. Amer. Mus. Nat. Hist. 3(3): 251-284. the Uncompahgre Upwarp in western Colo- RiGGS, E S 1903. Brachiosatirus altithorax, the largest Sci. 299-366. rado. 1 thank Dr. John S. Mcintosh for his dinosaur known. Amer. J. 15(4): 1904. Structure and relationships of opishtocoe- encouraging support. Dr. Samuel P. Wells lian dinosaurs. Field Columbian Mus. Geology and Dr. James R. Jensen for criticizing the Ser. 94(2): 229-247. manuscript, and Dr. Stephen L. Wood, edi- Romer, a. S. 1927. The pelvic musculature of ornithis- tor. Great Basin Naturalist, for his continuing chian dinosaurs. Acta. Zoologica Bd. 8: 225-275.