April 4, 2022 Scott Kraus

Massospondylus, aka M. carinatus

The “elongated spine” dinosaur, Massospondylus (Greek- Greater Vertebrae), pronounced mass-o-SPON-dih-lus, was a genus quadrupedal, semi-bipedal herbivore and possible omnivore from the Early Jurassic period. Otherwise known as Massospondylus carinatus, the standing species of the Massospondylus genus M. carinatus was a mid-sized prosauropod that lived during the Hettangian to Pliensbachian ages of the Early Jurassic Period, 200 to 183 million years ago.  Massospondylus was a common dinosaur in southern Africa during the age.  Massospondylus carinatus the prosauropod was very similar to Plateosaurus, but is distinguished by its smaller build and somewhat more primitive jaw structure.

Quick Facts

About Massospondylus

Prosauropods were early Saurischian dinosaurs that lived during the Triassic and Jurassic eras, but had become extinct by end of the Jurassic period.   Other prosauropods were Plateosaurus, Yunnanosaurus, and Riojasaurus.

M. kallae (Massopondylus Kallae) is known from the same time and region as M. carinatus.  Classified in 2009 on the basis of a partial skull, The specimen of M. kaalae is a partial skull, found in the Upper Elliot Formation at Voyizane farm.  This species differs from the type species M. carinatus in the morphology of the braincase.  There are other characteristics of the skull which also differentiate M. kallae from M. carinatus. 

What Did Massospondylus Look Like?

Always in prayer formation, Massopondylus had short forelimbs that were always set palm-facing-palm when in bipedal stance.  Sporting large, five-fingered ‘hands’, the thumbs on each of its forefeet had an extended sharp thumb claw that was used in defense and feeding.

The herbivore’s long neck enabled consumption of its leafy diet of plants and roots, high or low.  Once believed to be strictly quadrupedal, scientists later found Massospondylus to be bipedal in addition- and possibly near completely bipedal in adulthood.  This animal, 4–6 meters (13–20 feet) long, had a long neck and tail, with a small head and slender body. Recent studies indicate Massospondylus grew steadily throughout its lifespan

The Massospondylus embryo looked much like the adult, excepting the 4 legs of equal length and the absence of teeth.  It had the same thick body and elongated neck and long, thick tail of the adult form.  At the embryonic stage, Massospondylus could easily reach 6 inches long, still inside the egg.  …based on found specimens…the pre-hatchlings were toothless.  All four of any Massospondylus’ legs were equal in length, indicating to scientists that Massospondylus was born quadrupedal.  Discovery of the footprints of hatchlings supports quadrupedal origin.

Descendants of Massospondylus would develop into towering sauropods like Barosaurus and Brachiosaurus.

What did Massospondylus Eat?

Although the diet is believed to be primarily that of an herbivore, there are indications that Massospondylus would venture into carnivorous territory at some times, making Massospondylus potentially omnivorous.  Its long neck would reach up to the trees and other higher sources of vegetation available.  The Early Jurassic (about 190 million years ago) would have been covered with lush fern trees and conifers among many other fauna.

It’s believed that any meat Massospondylus ate was minimal, likely taking the form of tree nestlings hardly noticed but as morsels during its feasting upon the highest treetops.

How Did Massospondylus Move?

Massospondylus was a grazer and a tree-top browser that moved slowly or languidly at times, yet it is believed that Massospondylus was actually one of the fastest dinosaurs to have existed.  Dinosaur speeds are estimated using their body morphology- leg length, body mass, joint configuration, etc.  A quadrupedal, semi-bipedal  could walk on all fours, and likely grazed this way but primarily moved on powerful hindquarters in bipedal fashion and used forelimbs to assist eating.  Since Massospondylus was likely bipedal and quadrupedal, it likely ran on two legs- and, sometimes four.  if Massospondylus did evolve to a completely quadrupedal gait, this would not have necessarily been a positive or negative regarding speed.  It is thought the range of motion of Massospondylus would have prevented constant quadrupedal motion.

Massospondylus’ evolution could have been in a changing state, with the puzzling way that Massospondylus development resembles that of humans; infancy was awkward, with a more erect stance and evenly proportioned body only coming later after some time of growth.   Not a fearsome creature, Massospondylus would have been leery of any gang-operational predator or even a lurking leopard, which could outrun Massopondylus despite its great size.  It is believed that Massopondylus evolved a quick gait for survival and further evidence has been found in the South African excavation area of at least one additional predator of both Massospondylus (M. carinatus) and A. celestae.

Where Did Massospondylus Live?

Massospondylus lived in an area that would have been dominated by other prosauropods, theropods and primitive ornithischians by the time the Triassic period ended.  During the time of Massospondylus, their region of South Africa would have been a flat and arid one, part of a supercontinent with similar fauna across the land.  Today, the region is known for its sandstone mountains.  200 Million years ago, Massospondylus’ Triassic climate was probably hot and dry, with even the Polar Regions believed to be temperate climates.   Monsoons would have been frequent.  Conifers flourished in the Northern hemisphere and lush ferns in the Southern hemisphere.

The Discovery of Massospondylus

Prehistoric dinosaur remains of the Massospondylus are numerous and range in size from embryos to large adults.  First discovered in 1853 by J.M. Orpen, in the upper Elliot formation at Beaufort Abbey Harrismith, South Africa, the fossils were described in 1854 by paleontologist Sir Richard Owen.

Fossil hunter James Kitching discovered the clutch of Early Jurassic eggs in 1978 at Golden Gate Highlands National Park, Upper Elliot Formation at Blikania Mountain in South Africa (Eastern Cape). These date to the Hettangian-Sinemurian period and since then more nesting areas have been excavated, sometimes with up to 34 eggs per nest, which were recently excavated.   Up to ten nests per site have shown scientists many clues into the reproductive and rearing lives of some dinosaurs.  Scientists estimate that Massospondylus hatchlings were reared until double the size of their hatching.  Found in the SW Golden Gate Highlands national park, Free State territory, South Africa, this find is 100 Million years older than any previously discovered Massospondylus site.

Now characterized by sandstone mountains, the park, at the time of Massospondylus, was flat and much more arid.  It is claimed that there are more nesting Massospondylus hatchling fossils available to be excavated.   Prehistoric fossils are found throughout Africa, yet are more common in the south.

Massospondylus the Stony

Scientists found rounded stones in the stomachs of many Massopondylus specimens from South Africa.  It is believed that the dinosaur utilized these stones as a digestive aid for the rough plant materials consumed.  The stones found had a smooth surface, polished even.  It is thought that this would have been a natural consequence of sitting exposure to the acidic digestive acids and also to the grinding process.

It is well known that some animals use rocks in digestion, especially animals that have no teeth or inadequate teeth for their diet.  Since Massospondylus was hatched with no teeth, it is possible that rocks were introduced early in the lifespan.  Known as gastroliths, stomach stones or gizzard stones, the digestive aids were usually held inside a specialized organ with very strong muscle which accomplished the action of grinding.  Since not many gastroliths are found in relation to fossilized dinosaurs, it is difficult to come to conclusive theory on their actual purpose in the world of a particular prehistoric dinosaur.  Crocodiles are known to use stomach stones in order to decrease their own buoyancy in water, as it is believed that early water-bound reptiles also did.

The Significance of Massospondylus

The discovery of the massive Massospondylus nesting site in South Africa has been of great significance to the world of paleontology and prehistoric discovery.  As the earliest evidence to date of the genus Massospondylus, and including the evidence of its complex reproductive habits, the discovery informed scientists of Massospondylus’ considerations of nesting site fidelity and of the practice of colonial nesting.  The colonial nesting practiced by Massospondylus may or may not have been inherent to its beginnings, and may have evolved as a survival tactic.

Often confused with Aardonyx celestae, and since completely removed from any relation to the group other than likely sister taxon, Massospondylus of the sauropod order is a mystery to be further solved by closer inspection of its own and the A. celestae remains that are found in the same general areas of the African continent.  A. celestae has arm features that are intermediate between prosauropods and sauropods.  It’s believed that two-legged upright prosauropods evolved into the four-legged quadrupeds that were believed to be Massospondylus itself.  Now that scientists realize that Massospondylus was probably still bipedal despite possibly sometimes using all four legs, Massospondylus, along with A celestae, still offers plenty of opportunity for study and understanding of evolutionary principles and benchmarks.