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mineralsrocksandfossiltalks · 5 months ago

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Monday Musings: Macronaria

If you have been following my posts this month you will recall the one I did on sauropod phylogeny at the beginning. Today I am going to focus on one clade: macronaria. The name "macronaria" means "large nose" referring to the large nasal opening in their skulls.

These sauropods first appeared in the middle Jurassic about 168-161 Ma and lasted all the way until the extinction of the non-avian dinosaurs in the late Cretaceous. They have been found on every continent except Antarctica.

In review, here are the characteristics or synapomorphies we use to diagnose macronarian sauropods:

Middle and posterior neural spines have distal ends that extend out transversely.

Posterior neural spines extend at the tip forming a triangular process upwards.

The anterior chevrons have an open proximal articulation.

Robust, spatulate, broad-crowned teeth.

Crests formed by large, protruding nasal.

Elongate metacarpals.

Forelimbs longer than hindlimbs.

Now here's a list of important or interesting macronarians:

ABROSAURUS

Discovered in 1984 near Zigong, China. It's name means "delicate lizard". It is from the middle Jurassic so one of the earliest in the clade and it is known from a nearly complete skull which is almost unheard of in sauropods.

AUSTRALOTITAN

Discovered in 2005 in Queensland, Australia, the "southern giant" is the largest dinosaur found on the island continent.

CAMARASAURUS

Found during the infamous Bone Wars, it is the most common sauropod in the Morrison Formation. Named in 1877 by Edward Drinker Cope, it means "chambered lizard". The first specimen was recovered from Cañon City, Colorado's Garden Park Quarry. Other specimens have come from Como Bluff, Wyoming; Fruita, Colorado; Dinosaur National Monument, Black Mesa, Oklahoma; South Dakota, New Mexico, and the Snowy Mountains of Montana. Over 500 specimens are known from both juvenile and adult animals. In fact, the most complete sauropod ever found was a juvenile Camarasaurus. You've probably seen it.

There are four species recognized: C. grandis, C. lewisi, C. lentus, and C. supremus. Stratigraphic evidence suggests an evolutionary progression of the genus through the Morrison Formation. C. grandis is the oldest occurring in the lower Salt Wash Member. It coexisted briefly with C. lewisi in the upper Salt Wash and with C. lentus in the lower Brushy Basin Member before vanishing. C. lentus continued till the bottom of the upper Brushy Basin where it briefly overlapped with C. supremus. This immediate succession of species as well as similarities suggests that C. supremus evolved directly from C. lentus.

EUHELOPUS

It was discovered in 1913 by a Catholic priest names Father R. Mertens and was the first dinosaur scientifically investigated in China.

FUKUITITAN

Described in 2010, this titanosaur from Japan is just fun to say.

LOURINHASAURUS

A camarasaurid found in Portugal in 1949. It comes from onw of the Morrison's sister formation, the Lourinha. It is incredibly similar to Camarasaurus with slightly longer front limbs.

VENENOSAURUS

A brachiosaurid from the early Cretaceous Cedar Mountain Formation. An adult and juvenile were found in 1998 in the Poison Strip Member.

ABYDOSAURUS

A brachiosaurid known from a complete skull. Found in the Mussentuchit Member of the Cedar Mountain Formation in Dinosaur National Monument, it was very similar to Giraffatitan with narrower teeth and a smaller nose.

BRACHIOSAURUS

Found during the Bone Wars in 1900 by Elmer Riggs in Fruita, Colorado, it was the largest dinosaur ever found at the time. Despite it's popularity though, very little is actually known about this dinosaur.

CEDAROSAURUS

Another brachiosaurid found in the Cedar Mountain Formation but in the Yellow Cat Member. Seems brachiosaurids lasted a bit in North America.

EUROPASAURUS

A brachiosaurid from late Jurassic Germany, it was identified as an example of insular dwarfism resulting from isolation on an island. It was only 20ft (6.2m) long!

GIRAFFATITAN

A brachiosaurid from the other Morrison sister formation, the Tendaguru. Once thought to be a species of Brachiosaurus, most reconstructions are actually based on this genus. It is the largest sauropod known from relatively complete material. The mounted specimen in Berlin is actually a subadult at about 73.7ft (22.46m) long and 40ft (12m) tall.

ARGENTINOSAURUS

A titanosaur from late Cretaceous Argentina, it is often considered the largest sauropod ever but with so little to go off that really is a bit of a leap. We need more skeletal remains.

ALAMOSAURUS

The only titanosaur found in North America. Remains have been recovered in Texas, Utah, New Mexico, and possibly Wyoming. Despite it's name, it was actually found in New Mexico first. This one is probably kore accurately the largest sauropod as we have more material.

#paleontology #fossils #dinosaur #fun facts #sauropod #Macronaria #brachiosaurus #camarasaurus #giraffatitan #argentinosaurus #alamosaurus

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a-dinosaur-a-day · 5 years ago

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Utahraptor ostrommaysi

By Nix, CC BY-NC 4.0

Etymology: Thief from Utah

First Described By: Kirkland et al., 1993

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Dromaeosauridae, Eudromaeosauria, Dromaeosaurinae

Status: Extinct

Time and Place: Between 129 and 120 million years go, from the Barremian to the Aptian ages of the Early Cretaceous

Utahraptor is known from the Yellow Cat and Poison Strip members of the Cedar Mountain Formation

Physical Description: Utahraptor was a very large raptor dinosaur, and had the associated bodily characteristics - a bulky trunk, shorter legs, long arms, large head, and long, stiffened tail. It was really and truly huge, about 7 meters long and 500 kilograms in weight - about the size of a modern Grizzley or Polar Bear, though they might have been heavier than previously thought. Like other raptors, it had huge sickle claws on its feet, and the claws were probably around 24 centimeters long - or even longer, if they had been covered in a keratin sheath as potentially thought. The skull of Utahraptor has not yet been described, so for now we can only say that it had a long, triangular head like other raptors, with sharp serrated teeth. As with other raptors, it would have been feathered - with very large wings for flapping, and a distinctively huge tail fan. The legs of Utahraptor would have been slightly less feathered, but still distinctive. In short, it was a big and fluffy bird-bear, and the largest predator in its environment.

By Matt Martyniuk, CC BY-SA 3.0

Diet: Utahraptor was a large predator and, accordingly, ate large sources of food such as ornithopods and younger sauropods.

By PaleoNeolitic, in the Public Domain

Behavior: As a raptor, Utahraptor would have been most analogous to a cat - probably stalking alone rather than in packs, and utilizing ambush behavior to trap its prey. Since it had somewhat stubby legs and wasn’t very fast at all, it couldn’t have relied on pursuit to attack its food, even if its food was just as slow as it was. Instead, these powerful legs helped Utahraptor to jump onto its food and surprise it, even from the ground where it spent its time. It then could use raptor prey restraint (RPR) to stay balanced on the prey, flapping its wings rapidly as the prey moved around and tried to escape. Those impossibly large sickle claws then were used to strategically stab at places where the prey would bleed out - important veins and arteries - rather than slash. In addition to this, Utahraptor would have been able to flap its wings rapidly and run up steep surfaces - a technique called Wing-Assisted Inclined Running (WAIR) - even vertical ones, like cliff faces and trees. This allowed Utahraptor to reach strategic vantage points and search for prey - and even jump down onto it from high heights. These techniques allowed Utahraptor to not only hunt the similarly-sized Ornithopods of the time, but also potentially attack the even larger Sauropods with which it shared its home. When it needed a smaller snack, that large claw could be used to pin down struggling furry mammals and lizards, in order for Utahraptor to then take a bite.

By Fred Wierum, CC By-SA 4.0

Though Utahraptor did not hunt in packs, that doesn’t mean it wasn’t social - and, indeed, there is considerable evidence not yet described that it lived in dense family groups. This would probably mean that adult Utahraptor would go out hunting on their own, while the little ones would gather their own food, before coming together in the same space for safety from other Utahraptor and just to spend the night. It is very likely that Utahraptor took care of its own young based on its relatives - and there’s hopefully more evidence on the way to corroborate this. This was a very complex social animal, using those fancy wings and tail fan to display to other Utahraptor - by holding up the wings and lifting the tail fan to display, it could communicate with others that it was a threat, that it wanted to mate, or to stay away from its nest. In general, it would have behaved very bird-like - walking around, bobbing its head, and moving its head to look for food and for each other rather than moving the eyes. And, like birds, it would have been very active, and warm-blooded.

By Ashley Patch

Ecosystem: When the Cedar Mountain Formation supported Utahraptor, it was a very large floodplain environment, that periodically flash flooded and filled the valley with mud. This was a seasonally wet environment with a variety of rivers, forests, prairies, and open woodlands. The ecosystem had a short wet system and a very long, tedious dry season. Utahraptor shared this environment with countless creatures - the tuataran Toxolophosaurus, the turtle Glyptops, a variety of fish, the mammaliaform Cifelliodon, and - of course - other dinosaurs. There was the ankylosaur Gastonia, the large Iguanodon-like Ornithopods Cedrorestes, Hippodraco, and Iguanacolossus; the Sauropods Cedarosaurus and Mierasaurus; the Therizinosaurs Martharaptor and Falcarius; the Troodontid Geminiraptor; the Ornithomimosaur Nedcolbertia; and another raptor - Yurgovuchia! This gave Utahraptor a wide variety of things to hunt in its environment.

By Emily Willoughby, CC By-SA 3.0

By the time of the later Poison Strip environment, things were changing rapidly in Cedar Mountain. Dry seasons were longer now, and a significant amount of sand was washing through the ecosystem. This made life higher in the floodplain, and probably eliminated many of the forests and river-woods that had been present prior to, leaving only a somewhat scrubland-esque plain. Accordingly, creature diversity actually went down - it was something of an ecosystem collapse. There was still food for Utahraptor to eat - the Ornithopod Planicoxa, and the sauropods Moabosaurus and Venenosaurus; but that was it. Utahraptor, thus, was living in a miniature extinction event - and disappears from the environment by the time the mud and rainy seasons returned in the Ruby Ranch Environment, and the large predator niche was replaced by the carnosaur Acrocanthosaurus.

By Calum O’Halloran

Other: Utahraptor was the largest raptor known, and we actually have many fossils of it - but they’re trapped in a block! Well, there isn’t funding to remove them from the block, anyway. So much more could be (and will be, dammit!) written about this excellent dinosaur if it was adequately funded to be researched properly. Check out the Utahraptor Project if you want to learn more about Utahraptor - and consider donating! Literally every penny helps. Utahraptor is also one of the inspirations for the raptors of Jurassic Park, along with Deinonychus - though, obviously, those creatures do not resemble their real counterparts in the slightest.

~ By Meig Dickson

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