the CARNIVOROUS DINOSAURS
- distinctly asymmetrical manus with digit II the longest digit [D&R p. 179]
- elongate posterior cervical vertebrae giving a long neck
- large curved claw on thumb (twisted digit I)
- antorbital fenestra well-developed
- large quadratojugal
- temporal musculature extends onto frontal
saurischian pelvis (primitive)
The Saurischian pelvis. Note the open acetabulum
and the anterior (to the left) pubis. Illustration from O. C. Marsh.
1896. The dinosaurs of North America. 16th Annual Report, U.S. Geological
Survey, pp. 133-244, 84 plates.
CLASSIFICATION OF THE THEROPODA
Ceratosaurus: Illustration from O. C. Marsh.
1896. The dinosaurs of North America.
Dinosaurs with a saurischian pelvis and sharp teeth and claws
- kinetic, flexible lower jaw
- large, ball-shaped occipital condyle provides extra mobility for the head [D&R p.
- 5 or more sacral vertebrae
- distal part of tail is stiff
- digits IV and V of manus (hand) reduced to absent
- digits II and III of hand elongate
- phalanges of digit V of foot lost
- digit I of pes (foot) is reduced and breaks contact with ankle
thin-walled, hollow limb bones and vertebrae
Lachrymal bone is prominently exposed on dorsal surface of skull
- Gautier (1986) lists 25 synapomorphies including; extra fenestra in the maxilla; narrow
elongate metatarsus; elongated zygopophyses on the vertebrae near the end of the tail;
- Padian, K., J. R. Hutchinson, and T. R. Holtz, Jr. 1999. Phylogenetic
definitions and nomenclature of the major taxonomic categories of the carnivorous
Dinosauria (Theropoda). Journal of Vertebrate Paleontology, 19: 69-80.
- Sereno, P. C. 1999. A rational for dinosaurian taxonomy. Journal of
Vertebrate Paleontology, 19: 788-790.
- The upper Triassic Eoraptor is
one of the
earliest dinosaurs, close to the
common dinosaur ancestor. Sereno considers it a primitive theropod, although others consider it a primitive dinosaur or
- 1 m long
- nearly-tridactyl hands indicate that it is a theropod (Sereno et al., 1993).
- Sereno, P. C., C. A. Forster, R. R. Rogers, A. M. Monetta. 1993. Primitive
dinosaur skeleton from Argentina and the early evolution of Dinosauria. Nature
- in prep. Sereno, P. C., R. N. Martinez, and O. A. Alcober. The primitive
dinosaur Eoraptor lunensis and the early evolution of Theropoda. Journal of
Vertebrate Paleontology, Supplement., MS 125 pp., 102 figs
Sereno considers the two or three genera of this family to be basal
theropods. Other suggest that they are dinosauromorphs that lack the
synapomorphies of the dinosauria. They are briefly discussed on my
ancestry of the dinosaurs page.
- reduction in hands and feet to three functional digits
- rotary wrist and a large grasping manus
- manus with fifth digit absent, fourth digit and metacarpal very
reduced to absent
- functionally three-toed foot: Digit V reduced to a splint of metatarsal and
Digit I drawn high up the metatarsals and not involved in weight
- light bones
- ?furcula (see below)
- late Triassic-late Cretaceous
- primitive theropods
- relatively small, lightly built forms (5-7 m long).
- loose attachment of premaxilla to maxilla
- narrow-boned pubis
- fusion of ilium, pubis, and ischium in adults
- neck vertebrae with two pairs of pleurocoels (hollow spaces)
- late Triassic - Early Jurassic
- Coelophysis, Late
Triassic, Chinle Group, Arizona, USA
Early Jurassic, Glen Canyon Group, Arizona, USA
- Syntarsus: -
Syntarsus kayentakatae, described by Tim Rowe in 1989, had two small crests, similar to those of larger coelophysoids like
Dilophosaurus. Learn more about this dinosaur from the UT
Digital Image Laboratory.
- late Jurassic - late Cretaceous
- includes all the theropods more advanced than the ceratosaurs.
- teeth lie entirely in front of orbit, beginning a trend of shortening of tooth row by
reduction of posterior teeth [D&R p. 184]
- maxillary fenestra present
- fusion of clavicle to form a furcula [D&R p. 184; synapomorphy for
- H. Bryant and A. Russell, 1993, JVP 13:171-184 considered the furcula is a possible
neomorph in maniraptorans; Chure, D. and J. Madsen, 1996, JVP 16:573-577 demonstrate a
furcula is present in allosaurids. Makovicky, P and P. Currie, 1998, JVP 18(1):143-149
provide evidence for furculae in tyrannosaurids and rerun Bryant and Russell's (1993)
congruence tests and conclude furculae are primitively present in theropods.)
- tall ascending process of the astragalus extends upward on tibia [D&R p. 185]
- end of pubis is expanded into a "boot" [D&R p. 191]
- posterior half of tail stiffened, lacks haemal arches
- three-fingered hand (digit IV is absent in adults)
is an early tetanurine that is neither a carnosaur or coelurosaur.
- Officially discovered around 1815, this is the first non-avian dinosaur to be formally
described (Buckland ,
1824). In 1676, Robert Plot
described the distal end of a megalosaur femur was described as the remains
of an elephant brought to Britain by the Romans. Richard Brooks in
1763 reillustrated the bone which he labeled Scrotum humanum [as a
descriptive appellation]. In 1768 Jean Baptiste Robinet described the
specimen a real scrotum.
- The Ardley megalosaur
- Sereno, P. C., A. L. Beck, D. B. Dutheil, B. Gado, H. C. E. Larsson, G. H.
Lyon, J.. D. Marcot, O. W. M. Rauhut, R. W. Sadleir, C. A. Sidor, D. D. Varricchio,
G. P. Wilson, and J. A.Wilson. 1998. A Long-Snouted Predatory Dinosaur from Africa
and the Evolution of Spinosaurids. Science 282:1298-1302
- Carnosauria plus Coelurosauria
- furcula (wishbone)
- sternum (breastbone)
- a rotary wrist and a large grasping manus
- loss of fourth and fifth fingers
- Pubic foot: anterior expansion of pubis
- Large meat eating dinosaurs that reached their peak in the Jurassic. Carnosaurs
formerly included Allosauridae and Tyranosauridae - the often very large dinosaurs of the
Jurassic and Cretaceous. Now it is recognized that tyrannosaurs and allosaurs are not
sister taxa and that large size evolved independently in both groups. The term is
restricted to the allosaurs, which are basal tetanurines.
- femur is usually larger than the tibia
- long, narrow skull. with large orbits
- antorbital fenestra expanded upwardly
- maxillary fenestra is expanded upwards forming a large hole in lacrimal bone
(this also occurs in tyrannosaurids)
- many allosauroids had crests on top of their heads
- Allosaurus fragilis,
Late Jurassic, Morrison Formation, Western USA
an early Cretaceous Texas carnosaur
- Fran the Acrocanthosaurus
atokensis from Oklahoma
Cretaceous (Albian-Cenomian), Africa
- A giant theropod, rivaling Tyrannosaurus in size, if not mass.
According to Paul
Sereno (in 1995), it is the largest carnivore to have walked the
earth. It has an
estimated head length of 153 cm, which is less than the 165 cm of Giganotosaurus.
- Giganotosaurus carolinenii
named in 1995 is a carcharodontosaurine from the late Cretaceous (Cenomian), Patagonia, Argentina.
hunting; more on pack
- Compsognathidae, Theriznosauridae, Tyrannosauroidea and Maniraptora
- metatarsal lII is pinched between metatarsals II and IV, making a stronger foot [D&R
- sternal plates fused (solid, bony sternum)
- elongate, slender forelimb and hand (forelimb is at least half the length of hindlimb)
- fenestra in roof of mouth.
- down-like feathers? (see Sinosauropterix). A discussion of
which dinosaurs had feathers by high-school student Grant
- Longisquama, a late Triassic gliding archosaur of uncertain
relationships, has been purported to have feathers (Jones et al., Science,
288: 2202-2205). This
a chicken-sized dinosaur (0.7-1.4 m long), Late Jurassic, Solenhofen
- also known from the Early Cretaceous, Liaoning lake beds, China.
- Ornitholestes, Late Jurassic,
Formation, Western USA
- Scipionyx, known from an exceptionally well-preserved specimen of a
juvenile shows traces of the intestines, windpipe, liver, and muscle fibers.
(Ji and Li, 1996), Early Cretaceous, Yixian Formation, Liaoning beds, China
- a chicken-sized dinosaur with a fringe of down-like structures
along its neck and backbone
- Chen, P., Z. Dong and S. Zhen 1997 "An exceptionally well preserved theropod dinosaur from the Yixian
Formation of China." Nature 391:147-152
- Tyranosauridae and Ornithomimosauria
- metatarsal III tapers to a thin wedge proximally near the ankle joint
- metatarsals are slender, deep, and elongate
- Albertosaurus, Late Cretaceous, Judith River beds, Alberta, Canada
- Learn more about the 8-10 meter long Albertosaurus from the
- Tarbosaurus, Late
- Tyrannosaurus Late Cretaceous, Hell Creek Formation, Montana; Judith River beds, Alberta
- contrast the 1915 and recent mounts at the AMNH
at the UCMP;
- The 12-14 meter long, 8 ton Tyrannosaurus is one of the largest terrestrial meat-eaters, ever,
although it has been exceeded by some recent discoveries (such as Giganotosaurus).
- Jack Horner suggests that T
rex was a scavenger, not a predator.
- T rex
as a plodder
family life: a painting by John Lanzendorf
- An astounding recent
dinosaur discovery from southwestern Saskatchewan (Chin, K., T. T. Tokaryk,
G. M. Erickson
& L. C. Clark. 1998. A king-sized theropod coprolite. Nature 393: 680-682. ) is of a
tyrannosaur coprolite 44 cm long (17 inches long, six inches wide and five inches tall,
weighing nearly 16 pounds) containing shattered bones.
- Bite marks attributable to Tyrannosaurus occur on Edmontosaurus and
Triceratops bones [Bite marks attributable to Tyrannosaurus rex: Preliminary
description and implications . G. M. Erickson, and K. H. Olson, Journal of Vertebrate Paleontology, 1996, 16(1):
175-178.]. Erickson has also demonstrated that the jaws
of Tyrannosaurus exerted a bite force of between 1,400 and 3,000 pounds,
"greater than the crushing force of any known creature though close to the maximum force exerted by the American
alligator." [Erickson, G. M., S. D. Van Kirk, J. Su, M. E. Levenston,
W. E. Caler, and D. R. Carter. 1996. Bite-force estimation for Tyrannosaurus rex from tooth-marked bones. Nature, 382:706-7]
- Body mass, bone ''strength indicator'', and cursorial potential of
J. O. Farlow, M. B. Smith, and J. M. Robinson, Journal of Vertebrate Paleontology, 1995, 15(4): 713-725
the cannibal from Jeff Polling
- Brochu, C. A. 2003. Osteology of Tyrannosaurus rex:
Insights from a nearly complete skeleton and high-resolution Computed
Tomographic Analysis of the skull. Society of Vertebrate
Paleontology, Memoir 7, Journal of Vertebrate Paleontology, 22,
Supplement to Number 4: 1-138
- slightly built; medium to large-size ostrich-like dinosaurs
- toothless jaws in later forms
- beak-like snout
- elongate hindlimbs
- non-raptorial hand
- manus with nearly equal length metacarpals; etc.
- gastroliths from ornithomimids indicate an herbivorous diet (Kobayashi et
al., 1999. Nature 402: 480-481.)
- vaned feathers for food capture, display, and/or brooding
- long arms (forelimbs are >75% length of hindlimb) [D&R p. 190]
- bowed ulna and semilunate carpal [D&R p. 191]
- pubis is backturned [D&R p. 191]
- reduced or absent prefrontal
- reduced carpus
- posterior 3/4 of tail stiffened
- pubis points down and back
- front half of pubic boot is absent
- Strange looking dinosaurs with teeth lost in front of mouth and very large claws on
- The feet have four functional toes, unlike the other three-toed theropod
- Previously considered as possible relicts of the prosauropod-ornithischian
transition Sereno considers them the sister taxon of the
Ornithomimidae. Pisani et al. include them in the Oviraptosauria.
from the early Cretaceous of China has 'feathers' similar to those of the
primitive coelurosaur Sinosauropteryx.
- Xu, X., Z. Tang and X. Wang 1999 "A therizinosauroid dinosaur with integumentary structures from
China". Nature 399:350-354.
- Therizinosaurus, Late
- Segnosaurus, Late
Previously considered ornithomimids, now included in maniraptors. Oviraptor
was first discovered in Mongolia near what was thought to be the nest of a Protoceratops,
presumably intent on stealing an egg. In fact, inside the eggs are skeletons of
fetuses of Oviraptor. A recent
discovery is of an Oviraptor on top of a nest of eggs which she may have been
brooding like a bird. To learn much more about oviraptosaurs, visit Jaime A. Headden's Qilong
- skull deep, highly fenestrate, with a large crest
- lacking teeth, having instead a toothless beak
- bulbous, relatively large braincase
- many small teeth with large denticles
- Some consider this family to be the sister taxon of the Ornithomimidae
- Troodon, Late Cretaceous, Judith River beds, Alberta, Canada
- Sinornithoides, Early Cretaceous, Mongolia
- down-like feathers on body and tail for insulation
- vaned, symmetrical feathers forming a fan along the tail.
Flying birds have asymmetrical feathers.
- Kesey considers it to be a primitive maniraptoran
- Qiang, J., P. Currie, M. Norell, and J. Shu-An 1998 "Two feathered dinosaurs from
northeastern China." Nature 393:753-761
Dromaeosauridae see Currie; 1995; Journal of Vertebrate
- giant, hook-like claw on digit II of foot
- posterior 80% of tail stiffened with very elongate haemal and neural arches
- Deinonychus antirrhopus , Early Cretaceous, Cloverly Formation,
- Velociraptor mongoliensis, Late Cretaceous, Mongolia
- Dromaeosaurus, late Cretaceous, Alberta, Canada.
- Megaraptor late
- a maniraptoran with a large claw, but may not be a dromaeosaur. Megaraptor has a page
comparing it with Deinonychus and Utaraptor. about 8 m long
- 39 cm long, but 24 cm's of that was a long straight tail.
(Xu, X. 2000. Nature vol 408, p 705)
- Feathers on the front and hind limb ("four-winged") for
gliding. (Xu et al. 2003, Nature, 421:335)
- sideways-flexing wrist
- longer arms and hand
- feathers with shaft, vane and barbs
- primary feathers attached to digit II (longest finger)
Ji, Currie, Norell, & Ji, 1998
- not quite capable of powered flight
- feather impressions at tail, back, thigh, and neck
- short arms and long legs
- specimen contains gastroliths
interprets this genus as a more primitive maniraptoran.
- Yixian Formation, Liaoning Province, China; early Cretaceous
- Ji, Q., Currie, P.J., Norell, M.A., and Ji, S.-A. 1998. Two feathered dinosaurs from
northeastern China. Nature 393: 753-761.
Geographic press release
This deinonychosaur may be the sister taxon to the birds. It has filamentous
feathers. Its arms are proportionally very long -- 80% as long as the legs.
The shoulder girdle has features like those of flying birds; it
could flap its arms..
- Yixian Formation, Liaoning Province, China; early Cretaceous
- Xing Xu, Xiao-Lin Wang, and Xiao-Chun Wu, Nature 401, September 16, 1999, pp.
- Xu, X., Zhou, Z.-h., and Prum, R. O. 2001. Branched integumental structures in
Sinornithosaurus and the origin of feathers. Nature 410(6825):200-204.
"Here we describe our observations of the filamentous integumental appendages of the basal dromaeosaurid dinosaur
Sinornithosaurus millenii, which indicate that they are compound structures composed of
multiple filaments. Furthermore, these appendages exhibit two types of
branching structure that are unique to avian feathers: filaments joined in a
basal tuft, and filaments joined at their bases in series along a central filament."
- the first birds, powered flight
- long flight-feathers on forelimb
- hallux (digit I) is reversed [D&R p. 192]
- arms at least as long as legs
- greatly enlarged brain
- fewer than 25 caudal vertebrae
- flight feathers
- furcula (fused clavicles) present, as in modern birds
- expanded sternum absent
- thecodont teeth
- long tail without a pygostyle
- metacarpals separate, not fused--claws on hands
- hand reduced to 3 digits
- pubis oriented intermediate between theropod and bird
- capable of gliding or powered flight as evidenced from the structure of the feathers and
- The postcranial skeleton is predominantly reptilian, the skull shows a combination of
primitive avian and archosaurian characters
- These small, strange looking dinosaurs have been difficult to place
taxonomically. They have odd-shaped single-digit forelimbs.
Ornithothorraces: all other birds. They are better adapted for powered flight
- pygostyle present;
- strutlike coracoid
- sternum present
Order Enantiornithoformes (Cretaceous)
- the predominant land birds of the Cretaceous; teeth and gastralia are
- Apsaravis ukhaana
- Norell, M.A. and Clarke, J.A. 2001. Fossil that fills a critical gap in avian
evolution. Nature 409(6817):181-184.
- loon-like sea birds of the Cretaceous
- teeth are present
Infraclass Neornithes ("New Birds")
- loss of teeth
Superorder PALEOGNATHAE (Cenozoic)
- mostly flightless birds; which have a flat sternum with poorly developed pectoral
muscles, that live primarily on Southern Continents
- ratites (kiwis, emus, cassowaries, rheas, ostriches, moas) and tinamous
- usual absence of flight feathers
- paleognathous palate (large vomers, small palatines, with pterygoid-vomer articulation
- sternum reduced, usually without a keel
- pygostyle poorly developed or absent.
- Aepyornis [fig. 17-21a], the elephantbird of Madagascar, stood around 3 m tall
and weighed about 660 kg, 20 lb. egg, 1 ft. long, 2 gallons; herbivore
- Dinornis, a moa from New Zealand stood 3.6 m tall and weighed up to 300 kg,
- Ostrich: largest living bird; 2.6 m tall; lives in Africa; eats plants and small
animals; ostrich up to 150 kg
- Emu: lives in Australia and reaches 6'
- Cassowary: lives in Australia & New Guinea
- Kiwi: 3 species that live in New Zealand
- Rhea: South America
- Tinamous: only group of ratites that fly, found in South America, Central America, and
Superorder NEOGNATHAE (Cenozoic)
- all other living birds Table 18-1
- carinates - the flying birds that have a keeled sternum on which the powerful flight
muscles insert. Some carinates have become flightless
- neognathous palate (small vomers, large palatines, pterygoid not reaching vomer
- About 22 orders, including the following:
- Order Podicipediformes: grebes;
- Order Anseriformes: waterfowl
- including ducks, geese, and swans:
- Trumpeter swan is the heaviest flying bird: trumpeter swan--17 kg;
- Order Pelicaniformes: marine birds;
- including pelicans, cormorants, anhingas
- Order Ciconiiformes: wading birds
- egrets, herons, ibises, spoon bills, and storks:
- new world vultures are probably closely related to storks
- The largest flying bird was the extinct giant condor, Argentavis, a
Teratornithidae (related to New World vultures) from the late Miocene of Argentina, that
weighed 75 kg, stood 2 m tall and had a wingspan of up to 8 m.
- Order Falconiformes: birds of prey;
- including hawks, eagles, falcons and Old World vultures
- Order Galliformes: fowl; including the chicken, turkey, grouse, and pheasants:
- Order Gruiformes:
- 12 families, including cranes, coots, rails
- terror cranes: extinct, flightless, giant (over 2 m tall), cursorial predators
evolved independently at least twice in the Gruiformes
- Diatryma: [Paleocene and Eocene of North America and Europe]
- Phorusrhacus [Miocene and Pliocene of South America] and Titanis
[Pliocene and Pleistocene of North America]
- Order Charadriiformes: shorebirds; including plovers, sandpipers, gulls, terns, and
- Order Gaviiformes: loons;
- Order Columbiformes: including pigeons, doves, and the recently extinct dodo:
- Order Psittaciformes: parrots and macaws;
- Order Strigiformes: owls;
- Order Apodiformes: hummingbirds and swifts;
- Order Piciformes: woodpeckers and toucans;
- Order Passeriformes: perching birds/songbirds;
- 64 families
- comprise about 1/2 of all species (4000 species) of birds,