LSC 294 — Dinosaurs

Udo Savalli Home

Lab 11
Carnivorous Dinosaurs

Herrerasauridae

Primitive group of Saurischian Dinosaurs Bipedal runner: long hind legs, short forelegs Relatively small size Squarish skull Superficially resemble Theropod dinosaurs Carnivorous Evolutionary relationships are uncertain (may be primitive members of Theropoda)

Herrerasaurus skeleton, Middle Triassic, Argentina (MAL1)

Theropoda

Coelophysoids The most primitive group of theropods 4 fingers per hand (an ancestral trait) Small to medium-sized Generally have a slender build Skull usually fairly elongated Some have crests on their heads Known from Triassic and early Jurassic Periods	Coelophysis fossil, Late Triassic Period, New Mexico (WDC2)

Ceratosauria Primitive, with 4 fingers per hand Medium to large size Some exhibit fairly typical proportions for large predatory dinosaurs Abelisauridae is a distinctive subgroup: Short, deep skulls with various knobs, bumps or horns Forelimbs greatly reduced, vestigial (but with 4 fingers)	Ceratosaurus skeleton, Late Jurassic Period, North America, Europe, Africa (MAL)

Carnosauria All subsequent theropods belong to the clade Tetanurae 3 Fingers (or fewer) per hand Tail relatively stiff 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) Note: in lab, the following group, the Megalosauridae, will be included with this group under the category "Carnosaurs"

Giganotosaurus skeleton, Late Cretaceous Period, Argentina (FMNH3)

Megalosauridae Megalosaurs are medium to large Very generalized theropod morphology; few obvious specializations Generally lack crests or horns on head Includes Megalosaurus, the first named dinosaur Note: in lab, this group will be included with the above in the "Carnosaurs"	Torvosaurus skeleton, Late Jurassic Period, North America (MAL)

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)	Suchomimus skull, Early Cretaceous Period, Africa (MAL)

Compsognathidae All subsequent Tetanurans belong to the clade Coelurosauria Enlarge sacrum Stiffened tail Tibia (lower leg) longer than femur (upper leg) Perhaps all had some sort of feathers or protofeathers Compsognathids were small, agile dinosaurs Proportionately long tails At least some (or all?) had simple proto-feathers

Compsognathus skeleton, Late Jurassic Period, Europe (MAL)

Tyrannosauroidea All have relatively blunt snout United by various subtle skeletal characteristics Primitive forms were relatively small, resembled other coelurosaurs Some primitive forms known to have simple protofeathers Derived Tyrannosaurids distinctive: Large size Proportionately large head Greatly reduced arms with only 2 fingers	Tyrannosaurus skeleton, Late Cretaceous Period, North America (MAL)

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 No evidence for or against feathers	Struthiomimus skeleton, Late Cretaceous Period, North America (MAL)

Oviraptosauria 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 skull, Late Cretaceous Period, Asia (WDC)

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 (AMNH4)

Deinonychosauria 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 The sister group to the birds Troödontids (Troödon and Anchiornis) had smaller slashing claws and smaller heads but larger brains	Velociraptor skeleton, Late Cretaceous Period, Asia (WDC)