HUNTERIA - Gregory S. Paul

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vol. 2 

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HUNTERIA 

Jocit:ta& 

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ISSN No. 0892-3701, University of Colorado 

Museum, Campus Box 315, Boulder, CO 80309-0315 

THE BRACHIOSAUR GIANTS OF 

THE MORRISON AND TENDAGURU WITH A DESCRIPTION 

OF A NEW SUBGENUS, GIRAFFATITAN, AND 

A COMPARISON OF THE WORLD'S LARGEST DINOSAURS 

Proceedings of the North American Paleontological Conference IV: 

The Golden Age of Dinosaurs - The Mid-Mesozoic Terrestrial Ecosystem of North America 

Field Trip and Colloquium. 

Host institutions: Museum of Western Colorado, Grand Junction, Colorado 

and University Museum, University of Colorado, Boulder. 

GREGORY S. PAUL 

3109 N. Calvert St. Side Apt. 

Baltimore, MD 21218 

ABSTRACT 

A new skeletal restoration of Brachiosaurus brancai shows that this gracile, giraffe-like taxon is a 

distinct subgenus from Brachiosaurus altithorax. Ultrasaurus macintoshi is a junior synonym of 

B. altithorax and is similar in size to the largest B. brancai specimen. A survey of exceptionally large 

sauropod remains indicates that the largest weighed about 50 tons in lean condition, but this size was 

probably not the ultimate limit of the group. HUltrasaurus" was not larger than the largest African 

brachiosaurs and published estimates of a body weight up to 190 tons are unwarranted exaggerations. 

INTRODUCTION 

Brachiosaurs are not only the largest of the Morrison 

dinosaurs, they are the largest terrestrial vertebrates of all time 

for which good remains are known. The first Morrison 

brachiosaur, Brachiosaurus altithorax, was discovered by 

Riggs (1901, 1903, 1904) in 1900. The east African Tendaguru 

quarries that contained Brachiosaurus brancai were 

discovered in 1907(Fraas, 1908;Janensch, 1914).Over the years· 

there has been a tendency to consider the North American 

--..----~~


in lean condition. The temporal and biogeographic implications 

these taxa have for their respective formations is 

considered. 

Museum abbreviations - AMNH American Museum of 

Natural History, New York; BMNH British Museum of 

Natural History, London; BYU Brigham Young University, 

Provo; CM Carnegie Museum of Natural History, Chicago; 

HMN Humboldt Museum fur Naturkunde, East Berlin; MLP 

Museo La Plata, La Plata; MNDN Museum National 

D'histoire Naturelle, Paris; PEM Port Elizabeth Museum, Port 

Elizabeth; YMP Yale Peabody Museum, New Haven. 

BRACHIOSAURUS BRANCAI 

Brachiosaurus brancai ]anensch 1914is by far the best 

known of the brachiosaurs, so a consideration of the group 

starts with this species. Although no one complete individual 

exists, multiple specimens make knowledge of its osteology 

almost complete. A full understanding of this species has been 

hindered by the absence of an accurate, detailed skeletal 

restoration. The Berlin mount, HMN SIl, is a composite made 

of different sized individuals, plus some bones modeled in 

plaster. Janensch's restoration of SITis schematic and includes 

postural and proportional errors. The methodologies for restoring 

sauropods and other dinosaurs are discussed in Paul (1987) 

and Paul and Chase (in press). 

The basis for the new skeletal restoration in Fig. 1 is the 

holotype and best specimen, and the one on display in Berlin, 

HMN SII. This individual includes a partial skull (S116, in 

Janensch, 1935-36),all but the first three neck vertebrae, dorsal 

vertebrae 1-4, 8?, lO-12and parts of others, most of the dorsal 

ribs, a sternal, scapular material, a coracoid, a complete 

forelimb and hand, the pubes, a partial femur, a fibula, and 

hindfoot bones. Another important specimen. is BMNH M 

23, which includes a complete though poorly figured dorsal 

column (Migeod, 1931, most of this specimen has since been 

destroyed; McIntosh pers. comm.). The HMN specimens 

figured by Janensch (1950a, 1961)provide virtually all the rest 

of the missing elements, including a hip, sacrum, and tail 

(HMN Aa). Only a few hindfoot bones' are absent. In addition 

to the excellent figures of the various elements provided 

by Janensch, the author used photographs taken of the HMN 

mount and material - extreme care was taken in executing 

the profile of each element in the skeletal restoration. Duplication 

of parts in the HMN sample of elements allow different 

sized individuals to be scaled to the size of HMN SIT 

(Table 1); consequently the confidence in the morphology and 

proportions of the restoration of HMN Sll is high. 

The skull is the complete HMN tl, modified slightly and 

scaled up to S116/SIT. The ball and socket head-neck articulation 

was highly mobile, but since the occipital condyle points 

down and backwards, the head was usually carried at a sharp 

angle to the neck. The neck articulates in a gentle S curve, 

a basic dinosaurian adaptation. Ball and socket central facets 

and very large zygapophyses that remained articulated under 

~ a wide range of motion show that the neck was very flexible. 

The dorsals are wedge shaped and form a gentle arch, another 

HUNTERIA VOL. II, no. 3, pp. 2, February 19, [988 

general dinosaur character. Janensch did not have a complete 

dorsal column and did not explain why he gave B. brancai 

11 dorsals, but BMNH M 23 indicates that there were 12 

dorsals (Migeod, 1931,and McIntosh, pers. cornrn.; dorsal 1 

is considered to be the first relatively short-centrum vertebra 

that supports a long dorsal rib). Although the dorsal centra 

also have ball and socket central articulations, the following 

features show that the posterior dorsal region was stiff: partly 

ossified interspinal ligaments; expanded neural spine heads that 

supported enlarged interspinal ligaments; auxiliary zygapophyses 

that interlock transversely; and a tendency for the 

posterior dorsals to coossify.The ball and socket centra of the 

posterior dorsals added strength to the rigid column. In a 

similar manner, birds have stiff backs in association with 

saddle-shaped central articulations. The anterior dorsals may 

have been moderately mobile in the vertical plane (Bakker, 

pers. comm.). The tail-base vertebrae are also wedge shaped 

and form a gentle upwards arch (Gilmore, 1932, 1937; 

]anensch, 1950a); moderate sized. zygapophyses show a fair 

degree of flexibility. A multitude of sauropod trackways show 

that they rarely if ever dragged their tails on the ground (Bird, 

1985; Dutuit and Oazzou, 1980; Langston, 1974; Lockley et 

al., 1986). 

Articulated sauropod skeletons show that the anterior ribs 

are swept backwards relative to the main axis of the body. 

Proceeding backwards the ribs become more perpendicular 

relative to the main axis, so the ribs bunch together towards 

their ends. The anterior ribs are straight shafted and vertical 

in front view of the body, forming a narrow, slab-sided chest 

for articulation with the shoulder girdle. The posterior ribs 

are curved and arch far out to the side, creating a cavernous 

abdominal cavity. 

B. brancai has enormous sternals. With their postero-lateral 

corners attaching to the first long, robust dorsal rib (number 

two) via a short sternal rib, the sternals help determine the 

breadth of the chest. A cartilaginous anterior sternum is 

restored in front of the paired sternals as per Norman (1980). 

The anterior sternum has grooved edges along which the coracoid 

glided back and forth (Bakker, 1975;Paul, 1987).Observe 

that the scapulocoracoid does not perform anato~ical violations 

as it rotates, contrary to Bennett and Dalzell (1973).Also 

note that the backswept ribs set the sternum and coracoids 

a bit behind a perpendicular to the cervico-dorsal transition, 

not forward of it. The deep chest and short coracoid are compatible 

with an upright scapula seen in most tetrapods, instead 

of a bird-like horizontal one as often shown. This is the normal 

tetrapod condition - only protobirds and birds with their 

extremely long coracoids and scapulae have horizontal 

scapulae. 

The detailed limb joint articulations of B. brancai are 

discussed elsewhere (Paul, 1987). Forelimb posture is erect and 

the forefoot gauge is narrow as shown by morphology and 

trackways (Bakker, 1971a,b,c, 1974, 1975; Bird, 1985; Dutuit 

and Ouazzou, 1980; Langston, 1974; Paul; 1987). A downwardly 

facing shoulder glenoid and distally restricted humeral 

condyles show that the forelimb was also columnar. [anensch 

(1961)correctly restored the long, unguligrade, circular arcade 

.1 

'\ 

I

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OJ 

rm 

Lengths mm 

Skull t 

13 Cervicals c 

Longest Cervical 

12 Dorsals c < 

Dorsals 6-12 c < 

5 Sacrals 

55 Caudals c < 

Longest Rib 

Scapula 

Scapula-coracoid 

Sternal 

Humerus 

Radius 

Metacarpal II 

Ilium 

Pubis 

Ischium 

Femur 

Tibia-asrragulus 

Fibula 

Metatarsal n 

Toe Claw I 

Height mm 

Tallest Dorsal 

Dorsal 12 

Circumference mm 

'" .~ 

~ 

,g't; 

()" 

'-:'E 1'0.. 

HMN 

XV2 

1300e 

Sll Y Ki24 

880 

8996p 

1155 

3781p 

1711p 

1150 

7404e 

2900e 2580 

2175e 192ge 

2660e 2360e 

1100 

2400e 2130 

1240 

635 

2350e 

1340 

1360e 

1150 

1195e 

2090e 

1150e 

1190 

276 

240e 

1320e 1170" 

790 

Femur 730 

Breadth mm 

Femoral Head 

Hir.dfooe Pad 

Meters 

Total Length' 

Total Height 

Rearing Height 

Shoulder Height 

Hip Height 

- 850e - 750p 

25e 

16e 

1ge 

6.8e 

5.4e 

22.Zp 

14.0 

17.0 

6.0 

4.8p 

1540 - 890 

-1090 

D 

1700 1600 

XVI 

2140 1550 

900 

940 

560 

Sa9 Aa 

1930 

J 

1050 

890 

925 

1610 

950 

960 

150 

130 

6530 

1190 

1 il 

6 

;.t:k 

c e 

" >- 

•..0 

E'3:S 

rri~ 

FMNH BYU 

P25107 

4760p 

2475 

950 

From :Paul 1988a 

10'" 

;q E~ 

1'0" 

~

of the hand. Contrary to previous reports, the sauropod hand 

is not at all elephant-like - in fact it is unique and has only 

a thumb claw and no hooves. As restored the femur/tibia 

or fibula ratio of SITis a little higher than in other specimens 

(Table 1), but as the femur is always just a little shorter than 

the humerus in brachiosaurs, this ratio must be correct. The 

hindlimb is also columnar, and the foot is unguligrade and 

very elephant-like (excepting the three or four big laterally 

splayed banana claws; the outer one or two toes are neither 

clawed nor hooved). The astragular distal articulation faces 

more downwards and less forwards in well preserved sauropod 

ankles, relative to those of digitigrade prosauropods; therefore 

the sauropod foot is posturally unguligrade instead of plantigrade 

as suggested by Cooper (1984). The extremely short 

metatarsus and toes backed by a big pad show that the ankle 

was nearly immobile. The animal is shown in an elephantlike 

amble (Muybridge, 1887), its fastest gait. 

The most important point about the mounted HMN Sll 

is that the presacrals on display are not the originals, they 

are plaster models. The centra of the dorsal models are 

significantly larger than those of the originals, and Janensch's 

(1950b)paper skeletal restoration includes the s.ameerror. Why 

the modeled centra are so long is not clear, for although the 

dorsals are moderately crushed and too fragile to mount, most 

of the centra appear to be little altered in length. With centra 

of proper length, the dorsal column of B. brancai is some 

20% shorter relative to the limbs than indicated by ]anensch, 

even though one more vertebra is included in the new restoration. 

Other errors in Janensch's restoration include vertical 

anterior dorsal ribs and a shoulder girdle that is consequently 

too far forward - as well as too high - on the ribcage; scapula 

and humerus too short, a sprawling forelimb, and a tail that 

is too long, too heavy, and droops. Burian's well known 

restoration of the species emphasizes these errors, and also 

shows the neck much too short (Spinar and Burian, 1972)~ 

In addition the claws are incorrect. Because the new restoration 

has a scaled up HMN Aa tail that is longer than it is 

in the mount and a dorsal column that is shorter, the 

differences cancel each other and the new restoration and the 

mount share nearly the same length of over 22 m. 

A very unusual feature ofB. brancai is the extreme height 

of dorsal vertebra 4, especially the neural spine, relative to 

both the cervicals and posterior dorsals. Unfortunately the 

immediately surrounding neural spines are not preserved, but 

it appears that this sauropod had "withers", tall neural spines 

over the shoulders (Figs. 1, 2B). Rebbachisaurus garasbae, 

a species possibly assignable to the Brachiosauridae, may have 

even taller withers (Lavocat, 1952).Withers are fairly common 

among mammals, but are unknown among other dinosaurs 

except for the chasmosaurian ceratopsids. This feature suggests 

that nuchal ligaments helped to support the neck. The withers' 

modest height and the long neck suggest the ligaments were 

rather low, like a camel's (Knight, 1947; Dimery et al., 1985). 

The ossified cervical "ligaments" cited by Migeod (1931) and 

Alexander (1985)are more probably displaced ends of the long 

cervical ribs (McIntosh, pers. comm.). Also unusual is the small 

size of the posterior dorsals, especially the centra. HMN Sll 

HUNTERIA VOL. IT, no. 3, pp. 4, February 19, 1988 


and BMNH M 26 have posterior centra that are only 9 inches 

long! Although brachiosaur posterior dorsals are very different 

from the great posterior dorsals and sacrals of diplodocids, it 

does not follow that brachiosaurs were weak in the back. 

Obviously these giants did perfectly well with the posterior 

dorsals they had. Brachiosaur dorsals were not as specialized 

for rearing up as were diplodocid dorsals (Bakker, 1971C,1978). 

On the other hand brachiosaurs were like all other dinosaurs 

in being hindlimb dominant - the center of gravity was 

towards the rear so the hindlimb was more robust and supported 

more weight than the forelimb. This weight distribution 

made it easier for brachiosaurs to rear in search of choice 

-I

, 

food items or to fight than it is for elephants, which, despite 

their forelimb dominance, also have the capacity to rear 

(Eltringham, 1982).Note that brachiosaurs are less hindlimb 

dominant than diplodocids (Anderson et al., 1985). 

BRACHlOSAUR GIANTS 

Corrected with shorter trunk, taller forelimbs, and withers 

B. brancai is even more giraffe-likethan previously realized. 

It is the only quadrupedal dinosaur which one would have 

to reach up to slap the belly as one walked under it! Most 

Figure l-Multiview skeletal restoration of Brachiosaurus (Giraffatitan) brancai holotype SII/S116 (skull), with some proportions and elements from 

other HMN specimens., Inset shows dorsal-sacral column and ilium ofB. (Brachiosaurus) altithorax holotype FMNH P25107 to same scale. Measurements 

in Table 1. ' 

HUNTERlA VOL. II, no. 3, pp. 5, February 19, 1988

.",..---------~------------ 

unusual for a tetrapod, much less a dinosaur, it is an 

exceptionally elegant and majestic design. 

A COMPARISON OF B. BRANCAI 

WITH B. ALTITHORAX 

AND THE DELTA GIANT 

The holorvpe of Brachiosaurus altithorax Riggs 1903 

FMNH, P25107 is the most complete North American 

brachiosaur specimen. It includes dorsals 6-12, ribs, sacrum, 

caudals 1 and 2, coracoid, humerus, ilium, and femur 

(Figs. 2A, 3F). This specimen is crushed to varying degrees, 

especiallyin the sacrum (dorsa-ventrally) and, to a lesserdegree 

in the dorsals (downwards to the right). 

, 

: If 

'- -- - " , 

..•• -:...--- .•. 

A 

I, 

...J'~--"'J.-'"___ I 

•... ~/, . 

B 


The holotype of the Delta or Uncompahgre giant 

Ultrasaurus macintoshi Jensen 1985is the crushed vertebra 

BYU 5000.(note that the specimen numbers applied to the 

Uncompahgre material by Jensen are sometimes contradictory, 

and hence those cited here are tentative). This vertebra has 

been identified as a posterior dorsal (Fig. 3E). However, its 

transversely narrow neural spine with a small head shows that 

it is an anterior dorsal. Clearly brachlosaurian in design, it 

is very similar to the anterior dorsals of B. altithorax. As 

far as can be told, BYU 5000 belongs to B. altithorax and 

is referred to it. Hence, U. macintoshi is not considered valid. 

The slenderness of the neural spine suggests that BYU 5000 

is forward of dorsal 6, so it bolsters our knowledge of the 

shoulder of B. altithorax. Also referable to B. altithorax 

is the extremely large (2690 mm long) Uncompahgre 

Figure 2~Dorsals 6-12 and sacraIs, longest rib and ilia of A) Brachiosaurus (Brachiosaurus) altithorax holotype FMNH P25107 and 

B) B. (Giraffatitan) brancai halo type HMN SIl and Aa, Drawn so that their respective humeri are to the same length, scale bars equal 1 m. Neither 

column is complete, the sacrals and ilia of HMN Aa are scaled up to SIl, the position of the longest dorsal rib is not certain in either, and some crushing 

is removed tram both examples. 

~HUNfERlA VOL. II, no. 3, pp. 6, February 19, 1988

scapulocoracoid (Jensen 1985a, BYU 5001, Fig 4A, popularly 

labeled "Ultrasaurus"). It has the short, rounded amerior 

scapular process, short rounded coracoid, narrow scapular 

neck, and broad, rounded blade fully compatible with a 

brachiosaur. Jensen suggests that the scapula blade was not 

as broad as in Brachiosaurus, but some B. brancai blades 

are similar in breadth. 

The caudals, scapula, coracoid, humerus, ilium, and femur 

ofB. altithorax and B. brancai are very similar, and though 

the limb bones of the former are a bit more robust these 

elements could belong to the same species. It is in the dorsal 

column and trunk that the significant differences occur. To 

start with, at any given point, the dorsal column of 

B. altithorax is about 25-30% longer relative to the humerus 

or femur than that ofB. brancai (Fig. 2, Table 1).Riggs (1903) 

commented on the unusually long ribs of the Morrison 

sauropod, and indeed the longest dorsal rib is some 10% longer 

relative to the humerus than in B. brancai. 

The dorsals of both species are crushed, hampering comparison, 

especially quantitative. The posterior dorsals appear 

to be fairly similar. However, all the dorsal centra of 

B. altithorax have pleurocoels that are about 50% larger than 

those ofB. brancai (Fig. 3E-G). The neural arches are taller 

A 

BRACHIOSAUR GIANTS 

and longer in B. altithorax, but are much narrower. The 

transverse processes form a shallow V in B. brancai; in 

B. altithorax they appear to be flatter. 

The anterior and mid dorsals differ the most. In B. brancai, 

dorsal 4 is very gracile, with very long, proximally deep, distally 

tapering transverse processes and a tall, slender neural spine. 

The centrum is rather small and short. Excepting the centrum, 

dorsal 4 differsgreatly from the posterior dorsals in being much 

taller and wider. In the upper portions, the anterior dorsals 

ofB. altithorax differ relatively little from the more posterior 

vertebrae - their neural spines and transverse processes are 

only a little longer. Compared to the posterior arches, the 

anterior arches are longer both vertically and fore and aft. 

Very notable is the length of the anterior dorsal centra 

relative to those of the posterior dorsals in B. altithorax. 

Incomplete columns, crushing, centra fusion, and incomplete 

measurements hamper quantitative comparisons. But in 

HMN SII and BMNH M 26, the anterior dorsals are about 

the same length as the posterior dorsals. In FMNH P25107 

the mid dorsal centra are about 50% longer than those of the 

posterior dorsals (Fig. 2). Such elongation of mid-anterior 

dorsals is most unusual for sauropods and dinosaurs - even 

in Diplodocus and Barosaurus only the first two dorsals 

F G 

Figure 3-Anterior dorsals in left lateral (top) and posterior (bottom) views, drawn to the same zygapophysis-to-bottom-of-centrum height. Dorsal 5 in 

A) Apatosaurus louisae CM 3018; B) Diplodocus carnegii CM 84; C) Camarasaurus grandis YPM 1901 or 1902; and D) Camarasaurus suprernus 

AMNH 5761. Anterior dorsal in E) B. (Brachiosaurus) altithorax referred BYU 5000; dorsal 6 in F) B. (B.) altithorax holotype FMNH P25107; and 

dorsal 4 in G) Brachiosaurus (Giraffatitan) brancai holotype HMN SI!. Data from Gilmore, 1937; Hatcher, 1901;Janensch, 1950a; Jensen, 1985a: Osborn 

and Mook, 1921; Ostrom and Mclntosh, 1966: Riggs, 1903. 

HUNTERIA VOL. II, no. 3, pp. 7, February 19, 1988

are elongated. The combination of lower anterior dorsal 

vertebrae and the apparent lack of a sharp change between 

the anterior and posterior dorsals shows that B. altithorax 

lacked the tall withers of B. brancai. If this is correct, then 

B. altithorax may have had a less developed, shorter neck 

than B. brancai. 

It appears that the two brachiosaurs are both derived relative 

to other sauropods in anterior dorsal design, but in different 

ways. B. brancai has tall withers but is normal in anterior 

dorsal centra length. B. altithorax is more normal in the 

shoulder spines, but has unusually long anterior dorsals. The 

latter is also longer, deeper, and much bulkier in the body 

relative to the limbs (see below). 

]anensch (1914)recognized the differencesbetween the North 

American and African forms and separated them at the species 

level. The next question is how do the differences between 

B. altithorax and B. brancai compare to those between 

other tetrapod genera and species. Simple proportional differences 

do not necessarily a genus make. A combination of 

proportional and morphological differences is more significant. 

In the context of other sauropods, the differences between 

these two brachiosaurs are more extreme than those found 

within other genera. In Camarasaurus supremus and 

C. grandis, dorsal 5 differs significantly, especially in the 

. neural arch (Fig.3C,D). The difference is great enough to question 

whether these species should be placed in the same genus, 

but- the differences appear to be less than between B. 

altithorax and B. brancai. Even Diplodocus and 

Apatosaurus show about the same degree of difference in 

their anterior dorsals as shown in the two brachiosaurs (Fig. 

3A,B). There is much less difference between the anterior dorsals 

of Diplodocus and Barosaurus (Lull, 1919).Indeed the 

latter may be considered subgenera, rather than full genera. 

Among other dinosaurs it is difficult to come up with a 

genus that shows as much variation in anterior dorsal design. 

For example Tyrannosaurus, Tarbosaurus and 

Dospietosaurus - which may form a single genus - do not. 

Indeed, such widely accepted large tetrapod genera as 

Varanus, Anas, and Canis show much more uniformity. 

An example of considerable variation in withers height is 

found in recent and living species of Bison. However, the 

withers are an important species-specificdisplay device in bison; 

the functional importance of differences in neck movement 

is reduced in these short necked animals. In brachiosaurs the 

long neck implies that differences in the withers were probably 

associated with differences in neck size and movement. 

A basic definition of anyone genus should include an important 

functional distinction from related species. The Morrison 

and Tendaguru brachiosaurs not only appear to show a significant 

functional difference, they appear to be phylogenetically 

derived in different ways. Since they also vary more from one 

another than most genera, it is considered probable that they 

represent different genera. Generic separation would also be 

useful in preventing the two taxa from being considered more 

similar than they really are. However, the incompleteness of 

the remains of B. altithorax makes it difficult to prove full 

generic separation, as does the small sample size of Morrison 

HUNTERlA VOL. IT, no. 3, pp. 8, February 19, 1988 


and Tendaguru dorsal columns. Therefore, only a separation 

at the subgeneric level is proposed below, with the option of 

raising the separation to the generic level left open for future 

developments. 

SYSTEMATIC PALEONTOLOGY 

Family Brachiosauridae Riggs 1903 

Genus Brachiosaurus Riggs 1903 

Synonym - Ultrasaurus Jensen 1985 

Type species - B. altithorax Riggs 1903 

Diagnosis. as per Riggs (1903, 1904)and ]anensch (1914, 1929, 

1935-36, 1950a,b) 

Subgenus Brachiosaurus (Brachiosaurus) (Riggs 1903) 

Diagnosis. as for species. 

Brachiosaurus (Brachiosaurus) altithorax Riggs 1903 

Synonym - Ultrasau1'Usmacintoshi 

Holotype - FMNH F25107 

Referred specimens - USNM 21903,BYU 5000, BYU 5001, 

BYU Potter Creek vertebra. 

Diagnosis. Robust overall; mid dorsal centra much longer than. 

posterior dorsal centra, anterior dorsal spines and transverse 

processes not much taller or wider than those of posterior 

dorsals; neural arches long, tall and narrow; transverse 

processes flat; dorsal centra pleurocoels large; dorsal column 

over twice humerus length and very long relative to vertebrae 

height; body massive relative to limbs. 

Discussion. So far most Morrison brachiosaurs, including the 

USNM humerus 21903 and the BYU Potter Creek posterior 

dorsal (Jensen, 1985a), appear to be referable to this species. 

An Uncompahgre anterior caudal BYU 5002 was incorrectly 

referred to U. macintoshi (Jensen, 1985a); its cleft neural 

spine and handle bar transverse processes are clearly those 

of a diplodocid, not a brachiosaur. 

If the Uncompahgre fauna come from the uppermost 

Morrison (Jensen, 1985b), then it is possible that the fauna's 

brachiosaurs represent a distinct population of oversized 

animals (see below). These could either be a temporal 

subspecies, which does not require formal recognition, or a 

separate species. The Morrison brachiosaur material is much 

too limited to prove any of these options. 

The name Ultrasaurus has appeared informally a number 

of times since 1978 (Jensen, 1978, 1985a; Lambert, 1983; 

McWhirter and McWhirter, 1986; Norman, 1985). However, 

lacking a designated type species and formal technical description, 

it does not meet the International Code of Zoological 

Nomenclature criteria for availability. Ultrasaurus tabriensis 

Kim (1983) was applied to a medium sized and nondiagnostic 

Korean sauropod humeral head that was mistaken for a 

gigantic proximal ulna. Despite these problems, a holotype 

(DGBU-1973) was effectively designated and described in a 

public technical text, sufficient to give the generic and specific 

names a place in formal systematics. Since the type and 

referred material (a caudal? neural spine) are nondiagnostic,

they should be considered Sauropoda incertae sedis, and 

Ultrasaurus should be considered no longer valid. This result 

is unfortunate because it effectively bars Jensen's (1985a) 

subsequent formal use of Vltrasaurus to designate any 

Uncompahgre remains. 

Subgenus Brachiosaurus (Giraffatitan) n. subgen. 

Etymology - Loosely "gigantic giraffe",in recognition of the 

taxon's giraffe-likeform. 

Diagnosis. as for species. 

Discussion. Arkell (1956) suggested that Brachiosaurus 

(Giraffati tan) was first named Gigantosaurus. Actually 

Gigantosaurus megalonyx Seeley 1869was applied to some 

ambiguous European sauropod remains. Gigantosaurus 

robustus Fraas 1908 was used to accommodate Tendaguru 

remains that he could not place in other Tendaguru taxa. 

Much of this material was later placed in Tornieria robusta 

Sternfeld 1911. 

Brachiosaurus (Giraffatitan) brancai Janensch 1914 

Synonym - B. fraasi Janensch 1914 

Holotype - HMN Sll and Sl 

Referred specimens - As per [anensch (1914,1929,1935-36, 

1950a,b, 1961) 

Diagnosis. Gracile overall; 25 presacrals and 12 dorsals; mid 

dorsal centra about same length as posterior dorsal centra, 

anterior dorsal spines and transverse processesmuch taller and 

wider than those of posterior dorsals and form shoulder 

withers; neural arches short vertically and fore and aft; 

transversely broad transverse processes that form a shallow 

V; dorsal centra pleurocoels moderate in size;dorsal column 

less than twice humerus length and short relative to vertebra 

height; body mass relatively modest relative to limbs. 

Discussion. All Tendaguru brachiosaur specimens are referred 

to this species, including B. fraasi, the type 

(HMN Y) of which Janensch (1961)in later years listed under 

B. brancai. However, the possibility that some of the 

Tendaguru remains belong to another taxon remains open. 

THE MORRISON AND TENDAGURU 

FORMATIONS AND 

THEIR BRACHIOSAURS 

That B. (B.) altithorax and B. (G.) brancai are probably 

less similar than thought somewhat reduces the similarities 

between the Morrison and Tendaguru Formation faunas 

(Arkell, 1956; Galton, 1977, 1980, 1982).This does not, by 

any means, discredit the probability of a land connection 

between North America and Africa. One possibility is that 

habitat differences between the two formations may be 

responsiblefor the differencesin the brachiosaurs, even though 

both formations seem to have been seasonally dry (Dodson 

et al., 1980;Russell, 1980).That the two brachiosaurs are about 

equally advanced is compatible with their respective formations 

being roughly equal in age - within the Upper 


Kimeridgian-Tithonian (Aitken, 1961;Arkell, 1956; Stokes, 

1985). Comparable age is suggested too by the very close 

similarity of some other elements of the two faunas (Galton, 

1977, 1980, 1982). Besides, it remains possible that B. (B.) 

altithorax or something like it lies unrecognized in the 

Tendaguru material, and that B. (G.) brancai is present in 

the Morrison. 

WHAT WAS THE BIGGEST? 

Riggs realized he had discovered an exceptionally great 

dinosaur, and the actual mass of these animals has aroused 

curiosity ever since. In order to determine their mass, which 

is a function of their volume, we must first consider their 

musculature. A detailed restoration of the contour muscles 

of B. (G.) brancai HMN SII is presented elsewhere (Paul, 

1987).The muscles are also profiled in solid black around the 

skeletal restoration given here. 

Generally B. (G.) brancai has been restored as a massively 

muscled animal wtih a heavy neck and tail and stout limbs 

(Colbert, 1962;Jackson and Matternes, 1972;Norman, 1985; 

Ostrom, 1978;Spinar and Burian, 1972;Watson and Zallinger, 

1960; BMNH commercial model). Burian's restoration is 

perhaps the epitome of this style. It is certainly incorrect. The 

intensely pneumatic and very bird-like neck vertebrae of 

sauropods were much lighter in life than they look as mineralized 

fossils, and the skulls they supported were small. This 

suggeststhat the cervical musculature was also light and rather 

bird-like, just sufficient to properly operate the head-neck 

system. The bulge of each neck vertebra was probably visible 

in life, as is the case in large ground birds, camels.and giraffes. 

The rigid, bird-like ribcage was lightly muscled also. 

However, like all herbivores, sauropods must have had big 

bellies that they kept filled with fermenting fodder to support 

the flourishing gut flora "necessary to break down plant 

materials. A ruminant-like system is, however, neither efficient 

or necessary for high digestiveefficiencyin animals of this size 

(Demmont and Soest, 1985).In ungulates and proboscideans 

the belly is as broad as it is deep (seerear views in Muybridge 

1887),and the arching posterior ribs ofB. (G.) brancai show 

this was the case here. Indeed it had an exceptionally large 

abdomen for a sauropod; only Camarasaurus matches it in 

this regard. The tail of B. (G.) brancai is very reduced, and 

muscles were probably extended only as far as the bones (as 

mummies show is true of hadrosaurs, Paul, 1987),except for 

the caudofemoralis, which bulges beyond the transverse 

processes. All of the author's sauropod restorations show the 

animals "lean", without fat reserves, as they would be toward 

the end of the dry season. Large herbivores sometimes carry 

an additional 15-33%of their lean mass as fat by the end of 

the heavy feeding season, although elephants are not noted 

for carrying large fat deposits (Carrington, 1959).Hence the 

maximum masses of each individual sauropod would likely 

have been about a sixth higher than listed in Table 1, perhaps 

as much as a third. Such fat was probably borne towards the 

base of the belly, and Bakker (pers. comm.) notes that 

crocodilians and adult monitor lizards have substantial fat 

HUNTERIA VOL. II, no. 3, pp. 9, February 19, 1988

...---------------- 

deposits on their tail. Sauropods may have had the same in 

season. On the other hand, being terrestrial animals that 

carried their tails aloft as weapons, it is possible that the tail 

was never so burdened. Because the restored tail makes up 

only 5% of the total mass in brachiosaurs, and just 15% even 

in big tailed Apatosaurus, even doubling the tail mass will 

not alter the total mass value much. 

The small size and shortness of such muscle leverage attachments 

as the deltoid crest, olecranon process, ilium, cnemial 

crest, and hypotarsus relative to other dinosaurs indicates a 

modest limb musculature in B. (G.) brancai. That the foot 

was immobile confirms that only light shank muscles were 

needed to operate it. The lightness of sauropod limb muscles 

is logical since sauropods were e1ephantinely slow, and modern 

elephants also have slender limb muscles (Knight, 1947; 

Muybridge, 1887).Since brachiosaurs were as hindlimb dominant 

as other sauropods, the forelimb musculature was more 

slender than that of the hindlimb. All sauropod trackways 

show that the hand lacked a large central palm pad; instead 

it was hollow aft and half moon shaped (Paul, 1987).The hindfoot 

differs in having a great elephant-like heel pad. 

A model of HMN Sil was sculpted in plasticine and its 

volume measured by water immersion. Since most live animals 

float, the specific gravity was assumed to be 0.9. The exception 

was the highly pneumatic neck which was measured 

separately and assigned a tentative specific gravity of 0.6. In 

this species the neck was 13% of the total volume. HMN Sil 

proved to weigh about 32 tons. This is far less than Colbert's 

(1962) estimate of 78 tons for the same specimen. Why. there 

is so much difference is hard to judge because no plans of the 

model Colbert used were published. Colbert's museum model 

was presumably based on an overly long-bodied version of 

HMN Sil. The neck is too heavily muscled; even more so is 

the tail which is restored heavier at the base than it is in the 

accompanying Apatosaurus model. The reverse is actually 

the case. Both pairs of brachiosaur limbs are muscled much 

too heavily, especially the forelimb which appears more robust 

than the hindlimb. In summary so much flesh could not be . 

borne by even SIl's giant skeleton. Bakker's (1975) estimate 

of 50 tons for brachiosaurs is also excessive for average sized 

individuals. 

On the other hand, Russell et al.'s (1980) estimate, based 

on vaguely defined limb bone circumference/mass estimate, 

is far too low at 15 tons - so little flesh simply cannot be 

stretched over the animal's great frame. In a more rigorous 

analysis of limb element circumference relative to mass in living 

and fossil tetrapods, Anderson et al. (1985) arrived at a much 

more reasonable 29 ton estimate. However, the apparent agreement 

between this and my estimate means less than it appears. 

Bone robustness can give only a "ball park" estimate because 

in modern animals mass varies up to a factor of two at any 

given limb circumference (Anderson et al., 1985).Comparable 

variation was certainly present in sauropods also. For example 

the limb bone circumference of Apatosaurus louisae 

CM 3018 predicts a mass of 35 tons, bigger than Sil. However, 

the latter's skeleton is definitely more voluminous than 

CM 3018, and a model shows the apatosaur weighed only 18 

HUNTERIA VOL. II, no. 3, pp. 10, February 19, 1988 


tons (Table 1). Clearly A. louisae was much more strong 

limbed relative to its mass than was B. (G.) brancai. 

The largest specimen of B. (G.) brancai is the fibula 

HMN XV2 (lanensch, 1950b, 1961);claims of bigger specimens 

are unsubstantiated. There is variability in fibula/humerus or 

femur ratios in various specimens, but assuming it is similar 

to Sil in proportions, XV2 is about 13% larger (Table 1). In 

this case this individual would weigh up to 45 tons. 

The mass ofB. (B.) altithorax FMNH P25107is lessreadily 

determined. To get a rough estimate it was assumed that the 

neck, tail, and limbs weighed the same relative to the femur 

as inB. (G.) brancai. This is a fairly safe assumption, except 

that the neck may actually be somewhat smaller. A new model 

of the trunk incorporating 12 dorsals was sculpted to determine 

this portion of the total mass. FMNH P25107 appears 

to have weighed about 35 tons; despite its shorter limbs it may 

have been heavier than HMN SIl. 

Jensen (1978, 1985a,b) suggests that the Uncompahgre 

brachicsaurs represent uniquely large individuals. However, 

the great scapulocoracoid BYU 5001 is not especially large 

because cross scaling indicates that B. (G.) brancai 

HMN XV2 also had a scapulocoracoid about this length 

(Table 1), and several other B. (G.) brancai scapulocoracoids 

are not much smaller (Fig. 4A,B). Presumably the gross dimensions 

of XV2 and 8YU 5001 were similar too. If so, then 

estimates that BYU 5001 weighed up to 190 tons (Lambert, 

1983; McWhirter and McWhirter, 1986; Norman, 1985) are 

overstated. Assuming that BYU 5001 belongs to 

B. (B.) altithorax, this individual was closer to 45-50 tons. 

Reported 3038 mm long Uncompahgre ribs (jensen, 1985b) 

may be brachiosaurid and are in the same range as estimated 

for 5001 and XV2 (Table 1).If the giant 1360mm long Uncompahgre 

cervical BYU 5002 actually is a single spined 

brachiosaur as Jensen (1985a) indicates (but see below), then 

it too has a size similar to that estimated for 5001 and XV2. 

The indefinite position of anterior dorsal BYU 5000 and the 

lack of comparable dorsals in FMNH P25107 makes it difficult 

to compare the two individuals' masses. Besides, vertebra 

height may be more variable relative to mass than long bone 

length. It is notable that B. (G.) brancai HMN XV2 probably 

had anterior dorsals of similar size to BYU 5000 

(Table 1). The Potter Creek posterior dorsal is also in the 

5000-XV2 size class. In summary, the fragmentary Uncompahgre 

remains indicate that B. (B.) altithorax was in much 

the same size class as - perhaps a little heavier than - the 

biggest B. (G.) brancai specimens. That "ultrasaurs" are 

unique species of truly exceptional size is unconfirmed. 

Having found that B. (G.) brancai and B. (B.) altithorax 

were similar in size, the question arises as to whether they 

were the largest known terrestrial tetrapods. The Uncompahgre 

holotype ofDystylosaurus edwini, dorsal 8YU 5750, 

may be brachiosaurian. It cannot belong to the same taxon 

as BYU 5000 because these two anterior dorsals are too 

different to belong within the dorsal series of one single species. 

In having a transversely broad neural arch, BYU 5750 is rather 

like B. (G.) brancai, but otherwise it is very different, especially 

in its short, broad spine. With a height of about 1100

mm, BYU 5750 is very large but not uniquely so and, without 

further data on the animal's form, its weight can not be 

determined more precisely.Among other brachiosaurs, Russell 

(1980) and Anderson et at. (1985) suggested that 

"Brachiosaurus" ataliensis was unusually large. If the 

specimen cited is the same one in Lapparent and Zbyszewski 

(1957), then the radius and tibia are shorter than those of 

HMN Sll (Table 1). The 1500 mm dorsals of the bizarre 

brachiosaur Rebbachisaurus garasbae are much taller than 

those of the biggest of the other brachiosaurs. This height is 

due to its unusually tall spines; the limb material shows the 

body is not overall very large (Lavocat, 1952). 

The largestof the PaluxyRiver prints, which may have been 

made by the brachiosaur Pleurocoelus (Bird, 1985),are in 

the very large sizeclass (Table 1).Russell (1980)notes that the 

Breviparopus trackways (Dutuit and Ouazzou, 1980) also 

indicate very large sauropods. Indeed they are about the size 

of the biggest brachiosaurs. That these trackways were made 

by animals unbuoyed by water, and that sauropods were 

terrestrial in habits, proves that animals much bigger than 

elephants and as big as most whales can be land creatures. 

Bakker (1971c) suggested that Morrison apatosaurs and 

camarasaurs were as large as brachiosaurs. The largest 

Apcroscurus specimen is an incomplete femur YFM 1840 

described by Marsh. He first estimated it to be over 2.4 m 

long (Marsh, 1878),but the final restoration is more correct 

at about 1950mm (Marsh, 1896).Scaling up from CM 3018, 

the animal should have weighed only some 23 tons (Table 1). 

Two proximal Apatosaurus femora, CM 83 and CM 33994 

(McIntosh, 1981),are not as large as YPM 1840;cM 83 is 

not as large as CM 3018.It is more difficult to calculate mass 

in Camarasaurus because a high fidelity skeletal model of 

a complete adult specimen has yet to be completed. Scaling 

up of complete juveniles suggeststhat the biggestknown adult 

specimens(in the Cope collection,including a 1800mm femur, 

Osborn and Mook, 1921)weighed 22 to 26 tons. 

At least one other Morrison sauropod may be as massive 

and much longer than the brachiosaurs. A 2440 mm long 

Uncompahgre scapulocoracoid (BYU 5500, popularly labeled 

"Supersaurus") was initially identified as a brachiosaur 

(Fig.4D). Jensen (1985a)no longer supports this identification. 

Instead its long, rectangular anterior scapular process with 

Figure 4-Scapulocoracoids drawn to the same scale of A) B. (Brachiosaurus) 

altithorax referred BYU 5001; B) B. (Giraffatitan) brancai 

HMN Sa 9 with coracoid scaled in from HMN Ki 74; C) Supersaurus 

vivanae referred BYU 5501; D) S. vivanae holotype BYU 5500; 

E) Diplodocus carnegii CM 84. Measurements in Table 1. 


a sharp anterodorsal corner, long rectangular coracoid, 

fairly broad scapular neck and short, modestly expanded 

scapular blade indicate it is a gracile, Diplodocus- or 

Barosaurus-like diplodocid. A 2700 mm long Uncompahgre 

scapulocoracoid (BYU 5501)is very similar and was correctly 

referred to the same taxon as BYU 5500 by Jensen (Fig 4C). 

Jensen placed the two shoulder girdles in the new Supersaurus 

viviane Jensen 1985. However, except for a longer 

upper blade, they are so extremely similar to Diplodocus 

(Hatcher, 1901) that congeneric status is very possible 

(Fig. 4C-E). On the other hand, the giant neck vertebra 

BYU 5003 is reconstructed with diplodocid-type double neural 

spines.If this reconstruction iscorrect, then the vertebra's great 

length suggests that these diplodocids are long necked 

Barosaurus. Scapulocoracoid BYU 5501 may belong to an 

animal with a 2600 mm femur, if the proportions were 

diplodocid-like.But because such gracilediplodocids are lightly 

built they probably weighed "only" some 50 tons, as large as 

the biggest brachiosaurs. Length is another matter, for 

assuming that BYU 5501 had about the same total length to 

scapulocoracoid length ratio as Diplodocus (Table 1) then 

it was some 42 m long. At 1130mm the diplodocid anterior 

caudal BYU 5002 is not much taller than those of 

Diplodocus CM 84 and USNM 10865, so it is not an 

especially large individual. Likewise the 12 articulated 

diplodocid caudals (BYU 5502) have a length of 300 mm, no 

longer than those of CM 84. Since these Uncompahgre 

caudals are so small, it is very unlikely that they belong to 

the same individuals as do either of the scapulocoracoids. 

"Seismosaurus" has been based on some fragmentary 

remains from the Morrison Formation (Gillette, 1987).The 

tall neural spined caudals are clearly those of a gracile 

diplodocid. They are of unusually large size, but since truly 

large Supersaurus caudals are not available for comparison, 

it is difficult to tell just how much so. If the total length was 

37 m long as suggested by Gillette, then it may have been 

smaller than Supersaurus. Note that the tall neural spines 

of the Supersaurus and "Seismosaurus" caudals mean that 

they probably had the massive hips typical of diplodocids - 

a rearing-up adaptation (Bakker, 1971c, 1978) that indicates 

that they also had the short forelimbs found in all complete 

diplodocid skeletons. 

Amphicoelias altus is another large gracile diplodocid 

(Osborn and Mook, 1921; the straight instead of forwardsloping 

posterior dorsal neural spine indicates it is a different 

taxon from other Diplodocus and Barosaurus species).The 

longest 1770 mm femur indicates a 16 ton animal, substantially 

heavier than regular sizedDiplodocus and Barosaurus 

specimens (Table 1).It is possiblethat Amphicoelias, Super. 

saurus, and "Seismosaurus" all represent one giant species. 

All the specimens may be from the uppermost Mortison, and, 

because not enough parts are shared in common to determine 

their real taxonomic status, the new names may be premature. 

Outside the Morrison a number of sauropods from southerly 

latitudes, which may represent titanosaurs, exhibit a tendency 

towards gigantism. A broken and incomplete MLP femur 

measures nearly 2200 mm, but was much longer when com- 

. ) 

,i3 , 


J 

I

plete (Table 1).Assuming a typical sauropod mass/femur length 

ratio it may have weighed over 50 tons. Lacking further data 

it is not possible to estimate the animal's total length. Another 

super-sized sauropod is the femur of the titanosaur Antarctosaurus 

giganteus (Huene, 1929; Van Valen, 1969; 

Table 1). It is in the same class as the biggest brachiosaur 

femora, but since the rest of the animal is poorly known, the 

best that can be said is that it was probably similar in mass 

too. The South African (Mclachlan and McMillan, 1976)and 

Laotian (Hoffet, 1942)femora Anderson et a1.(1985)cited are 

not from uniquely large individuals (Table 1). 

In the final analysis, B. (G.) brancai and B. (B.) altithorax 

were about as big as any other known sauropods. Just 

as importantly, B. (G.) brancai holds the record for the 

biggest species for which all of the skeleton is known. It was 

also the tallest, but not the longest. The largest known 

sauropods appear to cluster around 50 tons in lean condition, 

perhaps a third more in prime fat-bearing condition. This 

should not be taken as an ultimate limit. The sample of all 

known sauropods is a tiny fraction of the sampled populations 

available for many single species of living animals. Even 

larger sauropods certainly await discovery, and it is improbable 

that the largest were preserved in the fossil record. It is interesting 

that, in living tetrapods, extremely rare "world record" 

individuals are often twice as massive as average individuals 

(McWhirter and McWhirter, 1986).In this view sauropods of 

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Yale University Press, New Haven. 

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appearance of dinosaurs and their relatives. In: Czerkas, S. 

and Olsen, E. (eds.). Dinosaurs Past and Present. Los 

Angeles: Natural History Museum of Los Angeles County. 

pp. 4-49. 

Paul, GS and Chase, T in press. Vertebrate paleontological 

reconstructions In: Hodges, E. (ed.).The Guild Handbook 

of Scientific Illustration. New York: Van Nostrand 

Reinhold. 

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13:549-550. 

Riggs, E.R. 1903. Brachiosaurus altithorax, the largest 

known dinosaur. American Journal of Science (4) 

15:299-306. 

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dinosaurs, pt. II the Brachoisauridae. Field Columbian 

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HUNTERIA VOL II, no. 3, pp. 13, February 19, 1988

Russell, D., Beland, P. and McIntosh, ].S. 1980. Paleoecology 

of the dinosaurs ofTendaguru (Tanzania). Memoirs Societe 

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1-27. 

The neck of B. (G.) brancai HMN JII is about 0.3 m 

shorter than the 9.3 m neck of the primitive, 9 ton diplodocid 

Mamenchisaurus hochuanensis PMNH 3 (Young and 

Chow, 1972). It is likely that Supersaurus also had a longer 

neck than the largest Brachiosaurus. 

Martin (1987) restores the neck of the sauropod 

Cetiosaurus as barely able to reach the ground, rise above 

the height of the shoulders, or swing to either side. That such 

a neck of 14 bird-like vertebrae would be far less flexible than 

the giraffe's neck of 7 vertebrae is untenable. A high number 

of vertebrae directly implies great flexibility, since a stiff long 

neck is better achieved by lengthening a few vertebrae, as in 

the giraffe. Errors in Martin's restoration include a maximum 

raised neck posture that is really its normal, neutral S curve, 

zygapophyses that are virtually immobile, and an average of 

only 1.4° of motion from the centerline between each cervical. 

Instead, the sauropod cervical combination of ball and socket 

centra articulations with large zygapophyses was designed to 

maintain articulation over a much greater range of motion 

than Martin shows, especially when the bony joint areas were 

expanded by cartilagenous surfaces. Exactly how much more 

I am not sure, what one can learn from dry bone manipulations 

or paper studies is useful, but not necessarily true to life. 

Sauropod and giraffe cervicals are remarkably similar; study 

of the latter might prove helpful to the problem. Note that 

a modest 12° or so of rotation between successive segments 

in 6 posterior cervicals would allow the sauropod head to reach 


NOTES ADDED IN PROOF 

Van Valen, L. 1969. What was the largest dinosaur? Copeia 

1969:624-262 

Watson, ].W. and ZaUinger, R.F. 1960. Dinosaurs and Other 

Prehistoric Reptiles. New York: Golden Press. 

. high up. This mobility is plausible since many mammals can 

do the same with only 7 cervicals. The extreme neck 

inflexibility Martin restores in sauropods is also functionally 

illogical, since shorter necked ungulates can reach as far up 

and to the side relative to their size. Long necks are an extreme 

adaptation, and among land herbivores their only useful 

purpose is to increase the vertical reach of high browsers. Low 

browsers and grazers invariably have modest necks because 

they can always reach what they want by just taking a few 

steps towards it. 

Contrary to Martin (1987), the ilial pubic penducles of all 

sauropods were massive, buttressed from the front and inside 

by stout sacral ribs, and well able to bear the mass of a rearing 

individual. Note that sauropods only stood, or occasionally 

slowly walked, bipedally. They did not incur the stresses of 

fast bipedal motion. 

PMNH - Beijing Museum of Natural History, Beijing. 

Martin, ]. 1987. Mobility and feeding of Cetiosaurus 

(Saurischia, Sauropoda) - why the long neck? In: Currie, 

P.]. and Koster, E.H. (eds.). Fourth Symposium on 

Mesozoic Terrestrial Ecosystems. Drumheller: Tyrell 

Museum of Paleontology. pp. 150-155. 

Young c.c. and Chow X.]. 1972. On Mamenchisaurus 

hochuanensis. Paleontographica Sinica, A., Special Issue 

8:1-30 

Total cost of production of this paper was donated by Dinamation International, Chris Mays, President. 


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HUNTERIA - Gregory S. Paul

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