lecture 10 Flashcards
Megalosauroidea
(incl. spinosaurs)
* Megalosaurus
* Baryonyx
* Spinosaurus
Allosauroidea
(incl. carcharodontosauridae)
* Allosaurus
* Carcharodontosaurus
* Giganotosaurus
Megalosaurs
Members of megalosauroidea are characterized
by especially long skulls (very long snouts).
- This feature characterizes the megalosauridae but is
even more accentuated amongst spinosauridae.
- We will also see that the teeth of spinosaurs are unique.
Megalosaurus (“great lizard”)
was the first dinosaur
discovered and named, following the discovery of a
jaw fragment found in a coal mine in 1824.
- It is known from deposits in England that date to 166 Ma.
- Almost 200 years later and still no complete skeleton has
ever been found.
Megalosauroidea has two main
branches:
megalosauridae &
spinosauridae.
The spinosaurids
(“spined lizards”)
appear in the Late Jurassic and
persist until the early part of the Late
Cretaceous, an age often informally
dubbed the ‘Mid-Cretaceous’
The megalosaurids lineage dies out by the end of the__________
Jurassic.
Spinosauridae
Spinosaurs are large, specialized theropods with crocodile-like skulls
and long conical teeth well adapted to a piscivorous lifestyle.
Laterally-compressed jaws thicken and flare at the tip of the snout.
(fish eating theropods)
- See slide 5
Baryonyx
(“heavy claw”)
lived 130-125 Ma in England.
was the first fisheating dinosaur discovered.
We know this from fish tales being discovered in its stomach cavity
Slide 7
Spinosaurus (‘spine lizard’)
lived in northern Africa during the
‘mid-Cretaceous’. At one time it was thought to be as long as 17 m
but now the more likely max. length is 14-15 m. New discoveries
have dramatically changed how we think about this dinosaur.
Had a crocodile like tail which heped it move through water
Spinosaurus Holotype
In 1912 fossil elements were discovered in
Egypt by German paleontologist Ernst Stromer.
The holotype specimen was formally
described and named in 1915.
Nizar Ibrahim
Spinosaurus bones were rediscovered and in 2013 Nizar
Ibrahim and many colleagues excavated the only Spinosaurus
dig site in the world.
Spinosaurus
The discovery of skeletal elements of the
tail has led to interpretations of a semiaquatic lifestyle.
Allosauroidea
Allosaurs
(Allosauroidea) are
the least derived of
the avetheropods.
Evolutionary novelty
for this clade/group?
Pubic boot
Allosauridae
Allosauroidea include the allosaurids of Jurassic North
America, and the carcharodontosaurids of the Early and
‘mid’ Cretaceous southern continents.
¡ Some carcharodontosaurs reached massive size
Allosaurus (“different lizard”)
was the apex
predator during the Late Jurassic in North
America, preying on Stegosaurus, ornithopods,
and sauropods.
Carcharodontisauridae
Some of the largest and most impressive theropods of all
time belong to the carcharodontosauridae clade.
Carcharodontosaurus, Giganotosaurus and
Mapusaurus rival or are even bigger than T-rex.
Carcharodontosaurus
(“sharp
tooth lizard”) lived during the
‘mid’-Cretaceous Egypt. Fossils
were collected and described by
Ernst Stromer. These initial finds
were also destroyed by WWII
bombings, along with Spinosaurus.
Giganotosaurus
(jig-e-not-o-saur-us)
(“giant southern lizard”) lived in Patagonia,
Argentina during the ‘mid’-Cretaceous
(~97 Ma).
