BIO 113 — Dinosaurs

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Lab 11
Carnivorous Dinosaurs

Theropoda

Basal Theropods

Coelophysidae A primitive group of theropods 4 fingers per hand (an ancestral trait) Mostly small, with a slender build Skull usually fairly elongated Known primarily from Triassic Period	Coelophysis fossil, Late Triassic Period, New Mexico (WDC [Museums are identified at bottom of page])
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Dilophosauroids 1 finger reduced (appear to have only 3) Medium-sized, with moderately slender build Thin bone crests on head Known primarily from early Jurassic Period Paraphyletic: Dilophosaurus more closely related to ceratosaurs and tetanurans (below)	Sinosaurus fossil, Early Jurassic Period, China
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Ceratosauroids

Ceratosauridae 4 fingers per hand Medium to large size Fairly typical proportions for large predatory dinosaurs Several small horns on head	Ceratosaurus skeleton, Late Jurassic Period, North America, Europe, Africa (MAL)
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Noasauridae Small, slender dinosaurs Head small Some with projecting teeth (for fish catching?) Others were toothless	Masiakasaurus knopfleri skull cast, Late Cretaceous Period, Madagascar (CFM)

Abelisauridae Forelimbs greatly reduced, vestigial, but with 4 fingers Medium to large size Skulls are deep, and fairly short in derived forms Crests and bumps on head or face are typical	Carnotaurus skeleton, Late Cretaceous Period, Argentina (LAMNH)
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Tetanurans

"Carnosaurs"

Megalosauridae Megalosaurs are medium to large generalized theropods Few obvious specializations; lack crests or horns on head Large claw on thumb Includes Megalosaurus, the first named dinosaur Formerly included with other large theropods in the "Carnosauria"	Torvosaurus skeleton, Late Jurassic Period, North America (MAL)
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Spinosauridae Large to very large size Long, narrow snout with enlarged tip Small centrally-located crest on forehead Teeth conical, without serrations Most likely were piscivorous (fish eaters); some where semi-aquatic (the only known aquatic dinosaurs)	Spinosaurus aegyptiacus skeleton, Late Cretaceous Period, North Africa (CFM)
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Allosauroids A large, diverse group of generalized predators Mostly large to very large size Generally have somewhat elongated skulls with large orbits Many have ridge or horn above eye (but not unique to this group)	Giganotosaurus skeleton, Late Cretaceous Period, Argentina (FMNH)
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Theropods of Uncertain Relationships Relationships uncertain Probably not closely related to any major group (or each other) They will be treated as generic "Carnosaurs"	Monolophosaurus skeleton, Late Cretaceous Period, Argentina (WDC)

Coelurosauria

Compsognathidae (& other basal Coelurosaurs) Compsognathids were small, agile dinosaurs Proportionately long tails At least some (or all?) had simple proto-feathers This group may not be monophyletic: some, such as Sciurumimus are juveniles that may belong to another theropod group	Scipionyx juvenile fossil, Early Cretaceous Period, Europe (BHI)
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Tyrannosauroidea

Basal Tyrannosauroids Relatively primitive, similar to other basal coelurosaurs Small to medium size 3 fingers per hand (like most other theropods) Some known to have had feathers Megaraptors Medium sized, slender build Long, narrow skulls Long arms with 3 fingers; enlarged thumb claw Poorly known & only recently recognized; position in Tyrannosauroids is not certain	Suskityrannus skeleton, Late Cretaceous Period, NM (AZMNH)
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Tyrannosauridae Most derived group from the latest Cretaceous Large size Proportionately large head Greatly reduced arms with only 2 fingers

Tyrannosaurus skeleton, Late Cretaceous Period, North America (MAL)

View Larger Image Our Changing Views of Dinosaurs: Tyrannosaurus See lab manual Exercise 17 for more information View Larger Image Dinosaur Growth & Development: Tyrannosaurus See lab manual Exercise 17 for more information View Larger Image Species Differences: Tyrannosaurs See lab manual Exercise 17 for more information View Larger Image Anagenesis: Daspletosaurus See lab manual Exercise 17 for more information View Larger Image

Maniraptoriformes

Ornithomimosauria Ostrich Dinosaurs Slender build, with long legs, long slender necks Small heads that were toothless in most (or with tiny peg-like teeth) Gastroliths present; probably herbivorous or omnivorous One species known to have feathers	Struthiomimus skeleton, Late Cretaceous Period, North America (MAL)
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Alvarezsauridae Small, with long legs and neck Small heads with tubular snout Very short but powerful arms Single, massive claw on each hand Loose, filamentous feathers known from one species May have been termite specialists

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Therizinosauroidea Very unusually shaped theropods Size varies from small to large Body broad and heavy, with wide hips and short tail Long necks with small heads Very long arms with enormous claws Probably herbivorous Loose, filamentous feathers known from one species	Nothronychus skeleton, Late Cretaceous Period, Southwestern USA (AZMNH)
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Oviraptorosauria Long arms and short tails distinctive Most were small (but at least one large species) Very short skulls with (usually) toothless, parrot-like beak Some had prominent crests on their heads Feathers with flat vanes that may have functioned in display Diet uncertain: evidence for both herbivory and carnivory	Conchoraptor skeleton, Late Cretaceous Period, Mongolia (DRC)
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Scansoriopterygidae Eongated 3rd finger Finger and modified wrist bone support membranous wing in some Blunt, downcurved snout with large front teeth (projecting in some) Unique ribbon-like tail feathers Small size 4 known species Probably tree climbers and gliders

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Dromeosauridae Commonly referred to as "raptors" Very small to medium size Agile, with fairly long arms, long fingers Inner hind toe with a greatly enlarged, retractible slashing claw Skulls elongated Tails long and stiff Well developed feathers with vanes Some capable of gliding flight	Velociraptor skeleton, Late Cretaceous Period, Asia (WDC)
View Larger Image Our Changing Views of Dinosaurs: Deinonychus See lab manual Exercise 17 for more information View Larger Image

Troodontidae Similar to the Dromeosaurs, but with smaller slashing claw Mostly small sized Smaller heads than Dromeosaurs with distinctive teeth Relatively large-brained Well developed feathers with vanes	"Troodon" egg clutch, Late Cretaceous Period, MT (MotR)
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Anchiornithidae Probably the sister-group to birds (Class Aves) Formerly thought to be related to Troodontidae Generally shorter-snouted than Troodontids or Dromeosaurs Mostly small sized Well developed feathers with vanes: very bird-like

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