Sauropodomorpha

Life as "large"

Sauropodomorphs (sauros - lizard; pod - foot; morpho - form) were extremely large, not too bright, and now extinct. Isn't that what dinosaurs are all about?

But what about mighty and majestic? These dinosaurs pushed the extremes of terrestrial body size - to the tune of 75,000 kg and possibly more (Figure 8.1, p. 159). In doing so, they taxed biomechanical and physiological design - weight support, neural circuitry, respiration, digestion, everything - to the limit. Viewed from that perspective, sauropods were some of the most sophisticated animals that ever walked the face of the Earth.

Challenger 300 Range Map
Figure 8.2. Global distribution of Sauropodomorpha. Prosauropoda indicated by solid circles, Sauropoda indicated by open squares.

Sauropodomorphs lived for 160 million years, from the beginning of dinosaur history until its close. Over this long interval, sauro-podomorphs managed to walk or be carried to every continent (Figure 8.2), and spawned well over a hundred different species.

Who are sauropodomorphs?

Sauropodomorpha is a well-diagnosed group of saurischian dinosaurs (Figure 8.3). The group of dinosaurs that look like "brontosaurus" -Sauropoda - are but one part Sauropodomorpha; the other consists of a relatively short-lived clade: Prosauropoda (pro - before; see Figures 4.5 and 8.4). Sauropodomorphs are split roughly one-third to two-thirds between prosauropods and sauropods.

Sauropodomorpha

Saurischia

Dinosauria

Figure 8.3. Cladogram of Dinosauria emphasizing the monophyly of Sauropodomorpha. Derived characters include: at 1, relatively small skull (about 5% body length), deflected front end of the lower jaw, elongate lanceolate teeth with coarsely serrated crowns, at least ten neck vertebrae that form a very long neck, dorsal and caudal vertebrae added to the front and hind ends of the sacrum, enormous thumb equipped with an enlarged claw, a very large obturator foramen in the pubis, and an elongate femur.

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