| SYSTEMATIC BIOLOGY |
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| CLASS ARCHOSAUROMORPHA |
Archosauromorpha (ar-ko-SOR-o-MOR-fa) is made up of three Greek roots that mean "ancient lizard forms" [ancient- archaios (αρχαίος), lizard- savra (σαύρα), and form- morphi (μορφή)]. The reference is to the ancient lizards (i.e. dinosaurs) that make up most of the members of this class.
This group of vertebrates is remarkably diverse and has exploited environments on the land, water, and air since its appearance in the Permian. This monophyletic group of diapsids is sister to the Lepidosauromorpha and includes crocodilians, pterosaurs, rhynchosaurs, dinosaurs, and birds. Although the basal archosaurs were somewhat sprawling and lizard-like in their gaits, many evolved a more upright and bipedal stance. The crocodilian line appears to have evolved from a line that was bipedal, or partly bipedal (alternating between bipedal and quadripedal stances). Furthermore, bipedalism seems to have freed the forearms and allowed for the evolution of winged flight in two separate lines (pterosaurs and birds). The ankles of the crocodilians could rotate while most of the other archosaurs evolved a more simple hinge-like ankle joint.
Crocodilians as a group have returned to a semi-aquatic existence. Thus, they have returned to a sprawling, lizard-like stance with a deep, flattened tail for propulsion in the water. The once diverse group has been reduced to 23 species, which tend to be the top predators of tropical and subtropical wetlands.
Pterosaurs (from two Greek roots meaning "winged lizard") evolved true flight on outstretched bat-like wings during the Triassic Period. The skin was stretched tight and supported by an elongated fourth finger. Although thin, the skin of the wings, which could have a span of 13-15 meters for Quetzacoatlus, was strengthened by bands of collagen fibers. Traces of hair on the bodies of some pterosaur fossils suggests that they were endothermic. Thus, their presumed physiology and wing structure support the view that they were strong and agile fliers.
Dinosaurs (from two Greek roots meaning "terrible lizard"), or, more appropriately, the non-avian dinosaurs, appeared during the Triassic Period as small bipedal carnivores, and they formed two large groups defined by the structure of the pelvic girdle: the Saurischia ("lizard-hipped dinosaurs") and the Ornithischia ("bird-hipped dinosaurs) that flourished in the Jurassic and Cretaceous Periods. The saurischia include the theropods and sauropods, the most popular of the dinosaurians. Theropods ("beast-footed dinosaurs"), which remained bipedal and carnivorous, included Tyrannosaurus, Coelophysis, Velociraptor, and Troodon. Some of these taxa likely had feathers. The resemblance to birds is more than superficial. In fact, from a cladistic perspective, all birds are embedded within the theropods. The sauropods ("lizard-footed dinosaurs") included herbivorous taxa that returned to a quadrupedal stance and included the largest terrestrial vertebrates that have ever lived (e.g. Apatosaurus, Camarasaurus, Brachiosaurus, and Diplodocus). Typically, they had long necks, small heads, immense bodies on pillar-like legs, and long tails. Sauropods had weak teeth that could do little more than tear away plant stems, leaves, twigs, etc., but did allow them to consume large masses of food that they processed in large fermentation chambers.
The ornithischians were entirely herbivorous and included the armored ornithischians (thyreophores - "shield-bearers"), the horned ornithischians (ceratopsians- "horn-faced dinosaurs"), and the ornithopods (bird-footed dinosaurs). The thyreophores were quadrupedal animals with small heads, short necks, and large bodies on pillar-like legs. Their bodies were covered by nodules of bony armor or plates and most had defensive spikes or clubs on the ends of their tails. Some of the principle taxa included Stegasaurus and Ankylosaurus. The ceratopsians appeared as bipedal animals in the lower Cretaceous, but most evolved to become large quadrupeds by the middle of the Cretaceous. They were characterized by having an anterior shearing beak, the back of the skull expanded into a frill, and one or more horns on the face and/or frill. Common taxa included Protoceratops and Triceratops. The ornithopods remained bipedal or facultatively bipedal. The principle feature of the head was the evolution of batteries of cheek teeth that were inset, suggesting that they had a cheek and could masticate plants material much like a cow does. Most evolved a beak in the front of the jaw, which gave them the name, duck-billed dinosaurs. Complex crests that may have served as resonating chambers on many taxa point to the likelihood of communication by sound, a characteristic of highly social vertebrates. Indeed, evidence suggests that all of the dinosaurs lived in social groups.
Birds are the most successful of all tetrapods with more than 9,500 living species. They are characterized by having a body covered with feathers, a light skull with no teeth, a highly reduced tail, and thoracic/lumbar vertebrae that are fused. They retain the bipedal stance and foot structure characteristic of their theropod ancestors with the forelegs modified into wings that form airfoils made of relatively long flight feathers. Within this basic body plan, living birds show remarkable diversity in which they have exploited aerial environments as well as terrestrial, arboreal, and aquatic environments. They range in size from the ostrich (up to 3m tall and nearly 200kg) to the hummingbird that is no longer that 7 cm and weighs less than 2-5 g. More than 60% of all living birds belong to a single order (Passeriformes), commonly called the songbirds. In general, birds are highly social animals with elaborate behaviors that include complex vocalizations and ornate displays which often feature brightly colored plumage.
| HIERARCHICAL TAXONOMY OF THE CLASS ARCHOSAUROMORPHA. The following descriptions come from Benton (2005) and the Animal Diversity Web from the University of Michigan Museum of Zoology. The structure of the following system is also based, in part, on the phylogenetic treatment by Mikko's Phylogeny Web (from the Finnish Museum of Natural History). Taxa in red are extinct. |
 Photo of a crocodile in Costa Rica (left) and a painting of a pterosaur (right). |
 Painting of a hadrosaur, a member of the ornithischian dinosaurs (left) and a photo of a cockatiel, Nymphicus (right). |
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Image of Pterosaur from: http://www.nmnh.si.edu/paleo/PaleoArt/Historical/Highlights/pterosaur.html Image of Hadrosaur from : http://www.copyrightexpired.com/earlyimage/prehistoriclifebeforekt/hadrosaurus01.html Images of the crocodile and the cockatiel are from the Systematic Biology Biodiversity Archive. CLASS ARCHOSAUROMORPHA This is one of the most diverse
groups of extant and extinct vertebrates. It
includes crocodilians, pterodactyls, dinosaurs, and birds.
According to The class can divided into the following major groups: EXTINCT TOOTHED BIRDS PELACONIFORM+CICIONIIFORM
CLADE PERCHING
BIRD ASSEMBLAGE MOUSEBIRD-TROGON-HORNBILL-KINGFISHER
CLADE This
is a paraphyletic group of very different basal archosaurs.
They appeared in the upper Permian and disappeared by the end of the
Triassic. ORDER
UNNAMED BASAL ARCHOSAUR FAMILIES FAMILY
TRILOPHOSAURIDAE Herbivores.
These animals had heavy skulls with broad, flattened cheek teeth and an
anterior beak (ensheathed in horn?). These
secondarily lost the lower temporal fenestra. Upper
Triassic Trilophosaurus FAMILY
RHYNCHOSAURIDAE Herbivores.
They had specialized shearing teeth in the cheek region (two rows) and a
beak with a large overbite. These
characters suggest that they must have fed on very tough plants.
The hind feet had specialized claws that seem to have functioned in
digging. These were very successful
herbivores throughout the Triassic. Some
animals were up to 2m long. Triassic Hyperodapedon ORDER
PROLACERTIFORMES Carnivores,
somewhat lizard-like with very long necks. Some
likely were aquatic and fed on fish and cephalopods.
These were among the first of the archosauromorphs.
Upper
Permian to upper Triassic Protorosaurus, Tanystropheus, Prolacerta These animals all have the following characters: · Antorbital fenestra · Laterosphenoid · Lateral mandibular fenestra · Laterally flattened, not rounded, teeth INFRACLASS
UNNAMED+ ORDER
UNNAMED FAMILY
PROTEROSUCHIDAE These
were small (to 1.5m), slender and some-what sprawling carnivores.
Lower
Triassic Proterosuchus FAMILY
ERYTHROSUCHIDAE Very
large carnivores (up to 5m). They
had evolved a 3-pronged pelvis; a fourth trochanter on the femur, and an
elongate metatarsal 3 (longer than metatarsal 4). Middle
Triassic Vjushkovia FAMILY
EUPARKERIIDAE Members
of this family seem to have been quadripedal and bipedal.
They had evolved an s-shaped femur and dermal scales (osteoderms) that
went down the back. Middle
Triassic Euparkeria INFRACLASS CRUROTARSI (the crocodilian line) These animals, mainly carnivores, were characterized by an ankle joint that allowed rotation between the astragulus and the calcaneum. Unassigned Taxa: Doswellia, Tarjadia, Parringtonia. SUPERORDER
UNNAMED+ ORDER
PHYTOSAURIA FAMILY
PHYTOSAURIDAE Piscivores,
but also took tetrapods and carrion. They
had a nostril mound just before the eyes. Upper
Triassic Parasuchus,
Paleorhinus, Belodon, Ebrachosuchus, Mesorhinosaurus, Rutiodon, Smilosuchus,
Leptosuchus, Phytosaurus, Angistorhinopsis, Coburgosuchus, Nicrosaurus,
Mysteriosuchus, Redondasaurus, Pseudopalatus. FAMILY
ORNITHOSUCHIDAE (INCERTAE SEDIS) Carnivore.
These animals superficially resembled early dinosaurs in that they were
bipedal and quadripedal; however, they had the crocodilian ankle joint.
Upper
Triassic Ornithosuchus FAMILY
STAGONOLEPIDIDAE (INCERTAE SEDIS) Herbivores.
Also called aetosaurs, they had stocky bodies that were covered with bony
plates. They had a short skull with
a shovel snout that suggests rooting in the soil for tubers, etc. Upper
Triassic Stagonolepis FAMILY
RAUISUCHIDAE (INCERTAE SEDIS) Carnivores,
some quite large (6-7m). This may be
a paraphyletic group of up to 4 families. Some
of these likely had an erect gait (pillar-like legs) and could move bipedally or
quadripedally. Upper
Triassic Saurosuchus FAMILY
POPOSAURIDAE (INCERTAE SEDIS) Carnivore.
Sometimes placed together with the rauchosuchids.
These had a high skull with recurved teeth, somewhat like the skulls of
theropod dinosaurs. Upper
Triassic Postosuchus SUPERORDER CROCODYLOMORPHA Major wrist bones modified as rods; coracoid with a long backward-pointing spine; pelvis with an open acetabulum. Also, specializations of the skull. Unassigned Taxa: Barbarenasuchus+, Clarencea+, Dyoplax+, Hallopus+, Macelognathus+, Parrishia+, Trialestes+. ORDER
UNNAMED+ FAMILY
SALTOPOSUCHIDAE Carnivore.
Long skull, and long hind legs, likely bipedal.
Animals small (0.5m). Upper
Triassic Saltoposuchus FAMILY
SPHENOSUCHIDAE Carnivore.
This animal had a heavier build and was larger (1.4m).
It could run fast, but it was a quadruped.
It showed other specializations in the skull that are diagnostic for
crocodilians. Upper
Triassic to lower Jurassic Sphenosuchus ORDER CROCODYLIA Unassigned Taxa: Eopneumatosuchus+, Microchampsa+, Artzosuchus+. FAMILY
PROTOSUCHIDAE+ The
protosuchids were small quadripedal animals with hind legs longer than the
forelegs (a consequence of a bipedal ancestry).
Posterior region of the skull is pneumatic. Lower
Jurassic Protosuchus,
Orthosuchus, Platyognathus, Dianosuchus, Erythrochampsa, Nothochampsa,
Stegmosuchus, Tagarosuchus, Hemiprotosuchus, Gobiosuchus. MESOEUCROCODYLIAN
CLADE FAMILY
TELEOSAURIDAE+ Marine
crocodilians with narrow snouts were piscivores of shallow coastal seas.
Lower
to middle Jurassic FAMILY
METRIORHYNCHIDAE+ These
animals were wholly aquatic with a tail fin (the end of the tail was down-turned
like the ichthyosaurs), the limbs were modified into paddles, and they had no
body armor. Upper
Jurassic Geosaurus FAMILY
NOTOSUCHIDAE+ These
were highly modified to a terrestrial existence.
They were small (a mater or less) and had modified teeth (sharp front
teeth and flattened ‘molars’. Some
may even have been herbivorous. Lower
Cretaceous Argentinosuchus,
Chimerasuchus FAMILY
SEBICIDAE+ Carnivores
with large skulls, high snouts, and laterally flattened teeth.
Paleocene
to Miocene Sebecus NEOSUCHIAN
CLADE These are
all heavily armored aquatic reptiles that superficially resemble lizards.
They are all somewhat aquatic. The
teeth are thecodont. Modern taxa
have webbed feet and nostrils on top of the head which can be closed by flaps.
The eyes can be covered by a clear membrane.
They have a muscular partition (similar to a diaphragm), alveoli in
the lungs, and a four-chambered heart. FAMILY
GONIOPHOLIDIDAE+ Aquatic
crocodilians with long snouts. Found
in marine and freshwater deposits. Middle
Jurassic to upper Cretaceous Coelosuchus,
Dakotasuchus, Microsaurus, Pinacosuchus, Pliogonodon, Polydectes, Kansajsuchus,
Oweniasuchus, Symptosuchus, Turanosuchus, Vectisuchus, Goniopholis, Sunosuchus,
Calsoyasuchus, Eutretauranosuchus. Bernissartia,
Gilchristosuchus, Rugosuchus. FAMILY
DYROSAURIDAE+ Some
of these were very large. The skull
of one large species was 1.8 m long and the estimated weight was 8 tons. Early
Cretaceous through the Eocene Chenanisuchus,
Sokotosuchus, Phosphatosaurus, Dyrosaurus, Arambourgisuchus, Congosaurus,
Rhabdognathus, Hyposaurus, Sarcosuchus EUSUCHIAN CLADE Unassigned Taxa:
Hylaeochampsa+,
Allodaposuchus+, Borealosuchus+, Pristichamphus+.. GAVIALOIDEA FAMILY GAVIALIDAE Gavials.
Freshwater from Eocene to present Gavialis,
Eothoracosaurus+, Thoracosaurus+, Argochampsa+,
Eosuchus+, Eogavialis+, Gryposuchus+, Ikanogavialis+, Sisquisiquesuchus+,
Piscogavialis+, Hesperogavialis+. CROCODYLOIDEA FAMILY CROCODYLIDAE Crocodiles
and False Gavials. Freshwater, brackish water and marine environments; Late Cretaceous to present Unassigned
Taxa: Prodiplocynodon+,
Asiatosuchus+, Aigialosuchus+, Charactosuchus+, Dollosuchus+, Holopsisuchus+,
Lianghusuchus+, Megadontosuchus+, Necrosuchus+, Planocrania+. Subfamily
Mekosuchinae+: Pallimnarchus, Australosuchus, Kembara, Baru, Trilophosuchus, Quinkana,
Volia, Mekosuchus. Subfamily
Crocodylinae: Crocodylus, Mecistops,
Osteolaemus, Euthecodon+. Subfamily
Tomistominae: Tomistoma, Cavialosuchus, Kentisuchus+,
Gavialosuchus+, Paratomistoma+, Thecachampsa+, Rhamphosuchus+. ALLIGATOROIDEA Unassigned Taxa: Leidyosuchus+,
Deinosuchus+, Strangerochampsa+, Brachychampsa+, Allodaposuchus+, Dinosuchus+,
Balanerodus+, Eoalligator+, Hispanochampsa+, Marrocosuchus+. FAMILY
DIPLOCYNODONTIDAE+ Tadzhikosuchus,
Baryphracta, Diplocynodon. FAMILY ALLIGATORIDAE Alligators.
Freshwater; Late Cretaceous to present Listrognathosuchus+,
Brachygnathosuchus+. Subfamily
Alligatorinae: Alligator, Akantosuchus+,
Albertochampsa+, Chrysochampsa+, Hassiacosuchus+, Navahosuchus+, Ceratosuchus+,
Allognathosuchus+, Wannaganosuchus+. Subfamily
Caimaninae: Caiman, Melanosuchus,
Paleosuchus, Necrosuchus+, Eocaiman+, Paleosuchus+,
Parussaurus+. FAMILY
NETTOSUCHIDAE+ Mourasuchus,
Orthogenysuchus, Nettosuchus. INFRACLASS
AVEMETATARSALIA+ SUPERORDER
FOR SCLEROMOCHLUS+ This
animal was the most basal of the Avemetatarsalia so far known.
That is, it is a sister to the Dinosauria+Pterosauria clade.
It was small (<0.2m) long and had several avian features.
It may have been a climber or a glider.
It might even have been able to hop.
Upper
Triassic Scleromochlus SUPERORDER
ORNITHODIRA The
ankle joint is simplified to a hinge joint.
The animal stands on its toes in a digitigrade posture. These
animals flew almost as a bat with wing membrane stretched by the hand.
However, in this case, only the fourth finger is elongated.
Their bodies seem to have been covered with hair.
They also had five long toes on their feet. SUBORDER
RHAMPHORHYNCHOPHORIDA These
likely are paraphyletic and include the collection of basal taxa.
Mostly fish eaters, they had long tails.
Upper
Triassic to Lower Cretaceous Eudimorphodon, Ramphorhynchus, Dimorphodon SUBORDER
PTERODACTYLOIDEA These
animals radiated into many ecological niches and some were as large as a small
airplane. In general, they had a
reduced tail and reduced, or highly
modified dentition. Some like Pteranodon
lost its teeth all together. Lower
to upper Cretaceous Pteranodon, Dsungaripteris, Ornithocheirus,
Pterodaustro, Ctenochasma, Quetzalcoatlus ORDER INCERTAE
SEDIS+ LAGERPETON, MARASUCHUS These
taxa appear to be basal dinosaurids and sisters to the rest of the dinosaurians
(including birds). Lagerpeton is known from fragmentary evidence while Marasuchus
is more completely known. Marasuchus was a small carnivore with an s-shaped neck, very long
hind limbs and features of the pelvis and leg that suggest it was a fully
bipedal animal. Its long tail also
served as a counter balance. Middle
Triassic Lagerpeton, Marasuchus The
lizard-hipped dinosaurs SUBORDER
UNNAMED FAMILY
HERRERASAURIDAE Carnivore.
Represented by two genera, both bipeds. They
both had a dinosaurian leg, pelvis, ankle, and skull which was relatively narrow
and high. There was a reduction of
toes in the fore and hind feet. Upper
Triassic Herrerasaurus,
Eoraptor This
includes all of the carnivorous dinosaurs (and technically also the birds) INFRAORDER
COELOPHYSOIDEA This
group had light bodies, long graceful necks and long tails.
It had a skull that was long and narrow.
The ischium was 2/3 or less as long as the pubis.
Well known. Coelophysis
ranges from 0.8-3.1m. Upper
Triassic to lower Jurassic Coelophysis INFRAORDER
CERATOSAURIA Theropods
with crests. FAMILY
CERATOSAURIDAE These
animals had crests or horn-like protuberances, which likely were for sexual
display. Jurassic Dilophosaurus,
Ceratosaurus FAMILY
ABELISAURIDAE These
had very short skulls with expansions of bone to form protuberances.
Middle
to upper Cretaceous Carnotaurus INFRAORDER
TETANURIDAE These
have the following features: Large
maxillary fenestra; teeth do not extend back of the antorbital fenestra; dorsal
vertebrae pleurocoelus CARNOSAURIA These
are the basal tetanurids, and they all have a distinctive maxilla, opisthocoelus
cervical vertebrae, and a very strong first metatarsal. FAMILY
MEGALOSAURIDAE Skull
narrow; orbit was high and smaller than the antorbital fenestra.
Middle
to upper Jurassic Megalosaurus,
Magnosaurus FAMILY
SPINOSAURIDAE These
had spiny sails on their backs, a characteristic large claw on the forefoot, and
an elongate alligator-like mouth. Cretaceous Baryonyx,
Suchomimus FAMILY
ALLOSAURIDAE Larger
than Megalsaurus, tall narrow orbit with heavy bony crests over them.
11-12m. Upper
Jurassic Allosaurus FAMILY
CARCHARODONTOSAURIDAE These
were very large with skulls 1.6m long. Cretaceous Carchodontosaurus COELOSAURIA
(SISTER TO THE AVES) The
coelosaurs share the following characters: enlarged maxillary fenestra,
premaxillary teeth without serrations. FAMILY
COELURIDAE The
basal coelosaurians. These were
small (0.7-1.4m) and had feathers. Upper
Jurassic Composgnathus,
Sinosauropteryx FAMILY
TYRRANOSAURIDAE Very
large predators (scavengers?). They
had an extra joint between dentary and post-dentary elements that increased the
gape and perhaps the force of the bite. They
had very small forelimbs with two or three digits.
The ankle was specialized such that all three metatarsals were locked
together (the arctometatarsus). Likely,
they could go no faster than 40km/hr. Upper
Cretaceous Tyrannosaurus,
Albertosaurus FAMILY
ORNITHOMIMIDAE These
animals had an ostrich-like body with long forelimbs, each terminating in three
digits. Early taxa had teeth, but
later ones had entirely toothless jaws that were covered with a horny beak.
The beak was ridged on the inside like that of a mallard duck
(function?). Upper
Jurassic to upper Cretaceous. Struthiomimus,
Dromiceiomimus THE MANIRAPTORA FAMILY
ALVAREZSAURIDAE These
animals were slender with oddly reduced forelimbs (Mononykus had only digit one
that was modified into a powerful spike). They
had certain avian featured that included a keeled sternum.
Femur shorter than the tibia and fibula reduced to a spike (as in a
chicken leg). Upper
Cretaceous Mononykus FAMILY
THERIZINOSAURIDAE These
animals were large (up to 5m) with a heavy pelvis, stocky legs, short tail and
relatively long forelimbs with three long digits.
The skull was small and had a few peg-like teeth and a beak at the front.
Likely it was a herbivore (foliage-eaters?). Upper
Cretaceous Alxasaurus
FAMILY
DROMAEOSAURIDAE These
were relatively small animals (up to 3 m) that were characterized by having a
specialized claw 2 that could swivel and slash.
Clearly predators, these animals may have hunted in packs.
Lower
Cretaceous Deinonychus,
Velociraptor FAMILY
TROODONTIDAE These
animals had slender necks and a head with very large orbits that faced forward
(binocular vision?). For a dinosaur,
its braincase was relatively large. Adapted
as a runner, its middle hind toe (toe 3) was the longest one as in birds.
Upper
Cretaceous Troodon OVORAPTOSAURS (SEE AVES) INFRAORDER
UNNAMED These
had 4 fused sacral vertebrae, a straight femur, no distal tarsals. BASAL
SAUROPOD FAMILY This
early animal shows the features common to the sauropod clade: a small head with
a down-turned lower jaw, lanceolate teeth with serrated crowns, long neck with
more than 10 cervical vertebrae, large thumb claw and no claws on toes 4&5,
a short blade on the ilium. This is
from a single genus, a relatively small (2.5m) bipedal animal. Upper
Jurassic Thecodontosaurus FAMILY
PLATEOSAURIDAE The
most typical of the prosauropods, the platyosaurids.
These animals could be quadrupedal or bipedal.
Upper
Triassic Plateosaurus,
Riojasaurus, Melanosaurus FAMILY
MASSOSPONDYLIDAE INFRAORDER
SAUROPODA NEOSAUROPODS The
fenestra on the lower jaw has been lost and the lower temporal fenestra lies
beneath the orbit. The legs are pillar-like.
Phalanges are lost FAMILY
CETIOSAURIDAE These
seem to be the precursors to the diplodocids and brachiosaurids, its hind legs
still are longer than the front legs. Middle
Jurassic Cetiosaurus FAMILY
OMEISAURIDAE These
animals had unusually long necks, even for sauropods. Upper
Jurassic Mamenchisaurus FAMILY
DIPLODOCIDAE Long
broad snout with long pencil-shaped teeth at the front of the jaws.
Their teeth angled out from the jaw, perhaps serving as a pincer to crop
vegetation. Nostrils are near the
top of the head between the eyes. There
has been much debate about the way in which the diplodocids used their necks.
The structure of the neck suggests that it could not flex the neck up
into an s-shape, but remained outstretched or raised only slightly. Upper
Jurassic Diplodocus MACRONARIA Enlarged
nasal ridge. Front legs longer than
the hind legs. Contains the most
massive terrestrial vertebrates known. FAMILY
CAMARASAURIDAE They
had hollow chambers in the vertebrae and forked neural spines.
The animals had a deep body and relatively long cervical ribs.
Camarasaurus,
Aragosaurus, Lourinhasaurus. FAMILY
BRACHIOSAURIDAE This
animal was a dinosaurian giraffe. It
could flex its neck upwards. Upper
Jurassic Brachiosaurus FAMILY
EUHELOPODIDAE The
jaws of these animals suggest that they ate tough vegetation. Middle
Jurassic Shunosaurus FAMILY
TITANOSAURIDAE These
were huge animals that reached the theoretical limits
of a terrestrial vertebrate. The
skull was similar to that of Diplodocus.
Some had armor plates embedded in their skin. Lower
to upper Cretaceous Argentinosaurus,
Nemegtosaurus, Quesitosaurus These
animals had a pubis that pointed backwards and all were herbivores. SUBORDER
UNNAMED The basal Ornithischia FAMILY
PISANOSAURIDAE This
is known from fragmentary evidence of the dentary and maxilla.
The cheek teeth had a deep root and blunt serrations.
The teeth are set back from the outer jaw suggesting that they had a
cheek for chewing. Upper
Triassic Pisanosaurus FAMILY
FABROSAURIDAE These
were small animals (less than a meter) with the ornithischian pelvis.
It had typical ornithiscian characters of the skull including a
predentary, the tip of which was toothless, in the lower jaw.
Lower
Jurassic Lesothosaurus These
were the armored ornithiscians. INFRAORDER
UNNAMED FAMILY
SCELIDOSAURIDAE These
were bipedal with rows of keeled scutes on the back and in rows on the sides. Lower
to middle Jurassic Scelidosaurus,
Scutellosaurus INFRAORDER
STEGOSAURIA They
were quadripeds with low, tube-like skulls.
The back had two rows of alternating triangular plates and a tail that
terminated in two rows of spikes. Upper
Jurassic Stegosaurus INFRAORDER
ANKYLOSAURIA FAMILY
NODOSAURIDAE These
had rows of spiny plates on the back and bony armor over the pelvis. Middle
Jurassic to Early Cretaceous Polocanthus FAMILY
ANKYLOSAURIDAE They
became heavily armored with armored skulls and bodies.
Their tail terminated in a large bony club.
Lower
to upper Cretaceous Ankylosaurus,
Euoplocephalus INFRAORDER
PACHYCEPHALOSAURIA These
bipedal animals had unusually thickened skull roofs and likely engaged in head
butting like modern sheep. Also,
their skeletons seem to have evolved to dissipate the force of a heavy blow to
the top of the head. Upper
Cretaceous Pachycephalosaurus, Prenocephale, Stegoceras,
Homalocephale INFRAORDER
CERATOPSIA These
animals had a beak-like rostral bone, which was covered with a horny beak, at
the tip of the upper jaw. FAMILY
PSITTACOSAURIDAE These
were bipedal with an ornithopod body, but a clearly ceratopsian head.
Lower
Cretaceous Psittacosaurus FAMILY
PROTOCERATOPSIDAE These
were quadripedal and had a characteristic frill and an incipient horn on the
nose. Middle
Cretaceous Protoceratops FAMILY
CERATOPSIDAE These
had limbs adapted for running and galloping.
They had tall neural spines on the back to which powerful neck muscled
were attached. The taxa varied
according to the frill and number and placement of horns.
The frills and horns likely served multiple purposes, among them, species
signaling and display, and defense. Upper
Cretaceous Triceratops,
Centrosaurus, Torosaurus FAMILY
HETERODONTOSAURIDAE These
animals had differentiated teeth: incisors, canines, and cheek teeth that were
inset suggesting a cheek. The
canines seem to have been part of their sexual dimorphism (some specimens,
presumably female, lacked them). Lower
Jurassic Heterodontosaurus FAMILY
HYPSILOPHODONTIDAE These
were similar to the heterodontosaurids, but they lacked tusks and their
forelimbs were relatively longer. They
had stiff tails and the proportions of the hind limbs suggest that they were
very fast runners. Upper
Jurassic to upper Cretaceous. Hypsilophodon FAMILY
IGUANODONTIDAE These
animals had a tail stiffened by ossified tendons and forelegs terminating in a
“hand” with small hooves and a thumb spike.
They could be bipeds or quadipeds. Lower
Cretaceous Iguanodon,
Ouranosaurus FAMILY
HADROSAURIDAE These
were the duck-billed dinosaurs. Their
jaws were toothless in the front which was sheathed by a horny beak.
Their cheek teeth grew in batteries of 5-6 rows with 45-60 teeth each,
clear adaptations to chewing tough plant material.
Some have a variety of crests, likely for display (visual and sound). Upper
Cretaceous Edmontosaurus,
Kritosaurus, Anatosaurus, Brachylophosaurus, Saurolophus, Parasauroolophus,
Lambeosaurus, Corythosaurus. INFRACLASS
UNNAMED These
animals had long bony tails and teeth. ORDER
UNNAMED FAMILY
ARCHAEOPTERYGIDAE In
most details like a small theropod. In
addition, they had at least 3 of the 5 air sacs found in birds.
The pubis seems to have been vertical (also seen in some theropods).
Its toe 1 is reflexed to lie at the back of the foot (reflexed hallux).
No evidence of a beak. Upper
Jurassic Archaeopteryx RAHONAVIS This
bird appears to be basal in structure but not in time.
It was a flyer with an enlarged 2nd toe.
Likely a member of the Archaeopterygidae but with some advanced features.
Upper
Cretaceous Rahonavis JEHOLORNIS This,
too appears to be close to Archaeopteryx, but it shows significantly advanced hand. INFRACLASS PYGOSTYLIA Animals with a tail reduced to a pygostyle. SUPERORDER
UNNAMED+ ORDER
UNNAMED FAMILY
CONFUCIUSORNITHIDAE They
have no teeth, but do have a horny beak. The
sacrum is fused to form the synsacrum characteristic of modern birds and the
tail has been reduced to 7 fused caudal vertebrae.
Lower
Cretaceous Confuciusornis,
Changchengornis ORDER
OVORAPTOROSAURIA These
animals are tentatively placed in the birds.
They were flightless, had a highly modified toothless skull, and a
pygostyle. Upper
Cretaceous Ovoraptor SUPERORDER
ORNITHOTHORACES+ ORDER
ENANTIORNITHES Birds
with teeth and short backs (<13 thoracic vertebrae) and other features of
modern birds. Characterized by the
presence of a tarsometatarsus (fused distal tarsals and metatarsals).
Lower
to upper Cretaceous Gobipteryx, Sinornis, Otogornis, Bolouchia,
Liaoxiornis, Longipteryx, Iberomesornis, Concornis, Eoalulavis ORDER INCERTAE
SEDIS PATAGONOPTERYX This
was a flightless bird with adaptations for running, an ecological equivalent to
the ratites (but not directly related to them).
Upper
Cretaceous Patagonopteryx VORONA Known
only from a hind leg. This animal
showed more complete fusion of the metatarsals than the eantionithes.
Upper
Cretaceous Vorona ORDER
HESPERORNITHIFORMES These
were toothed flightless diving birds whose wings were almost entirely reduced.
Upper
Cretaceous Hesperornis, Baptornis ORDER
ICHTHYORNIFORMES These
were diving birds that were good fliers. They
had large beaks lined with small sharp teeth.
Likely, the fished as terns do today.
Upper
Cretaceous Ichthyornis Other
upper Cretaceous Ornithurine birds of uncertain affinities include: Ambiortus,
These birds have a characteristic
palate (extensive vomer-pterygoid joint) ORDER
LITHORNITHIFORMES+ Variable
in size (hen to crane-sized). Some
could fly, others were flightless. Paleocene
to Eocene Lithornis,
Palaeotis RATITES These are represented by the tinnamous and ostriches-rheas-cassowaries-emus. They have become complete ground-dwelling animals and have lost the sternal keel. ORDER STRUTHIONIFORMES Typically, they are large to very large flightless birds that are adapted to running. They have a southern continental distribution. FAMILY APTERYGIDAE Kiwis.
Flightless birds of forests and open woodlands of Apteryx. FAMILY CASUARIIDAE Cassowaries.
Flightless birds of the rainforests and savannah woodlands of Papua-New
Guinea and northern Casuarius. FAMILY
DINORNITHIDAE+ Moas. Anomalopteryx,
Dinornis, Emeus, Euryapteryx, Megalapteryx, Pachyornis. FAMILY DROMAIIDAE Emus.
Flightless birds of the savannahs and semi-arid areas of Pleistocene to the present. Dromaius. FAMILY RHEIDAE Rheas.
Flightless birds of the pampas and scrub lands of tropical and temperate Pterocnemia,
Rhea. FAMILY STRUTHIONIDAE Ostriches.
Flightless birds of savannas and semi-arid regions of Struthio. ORDER TINAMIFORMES FAMILY TINAMIDAE Tinamous.
They are weak fliers of forests and savannah of most of Souh Miocene to the present Subfamily Rhynchotinae (Steppe Tinamous): Eudromia, Nothoprocta, Nothura, Rhynchotus, Taoniscus, Tinamotis. Subfamily
Tinaminae ( The largest group of extant
birds. They also have a
characteristic ankle in which the calcaneum, not the astragulus (as in the
ratites and theropods) forms the ascending process on the tibia. GALLOANSERAE Ducks and Fowl make up a
clade of birds that is the sister group of all other neognaths.
They have a fossil record that may go back to the upper Cretaceous.
Diatryma was large flightless
bird with a large beak (a predator?). ORDER ANSERIFORMES FAMILY ANATIDAE Swans, Geese, and Ducks. Aquatic birds of freshwater, brackish water, and marine environments of all continents, oceanic islands, and continental margins. They are medium to moderatedly large birds (0.30-1.80m) with wingspans of 0.43 to 2m. They have flattened bills that generally are adapted to filter feeding. They have long necks, large bodies, and short tails. Their diets include plants, fish, animal foods like fish eggs and invertebrates. Many are migratory. Subfamily Dendrocyninae (Whistling Ducks): Dendrocygna. Subfamily
Anserinae (Swans and Geese): Cyngus, Anser,
Branta, Tadorna, Plectopteris. SubfamilyAnatinae
(True Ducks): Alopochen, Nettapus, Aix, ,
Anas, Marmaronetta, Netta, Aythya, Somateria, Polysticta, Histrionicus,
Melanitta, Bucephala, Clangula, Mergus, Oxyura. FAMILY ANHIMIDAE Screamers. Anhima,
Chauna. FAMILY ANSERANATIDAE Magpie Geese. Anseranas. ORDER GALLIFORMES fowl FAMILY PHASIANIDAE Pheasants,
Partridges, Quails. Terrestrial
birds of forest and open habitats through Lower Eocene to the present. Subfamily Perdicinae (Partridges): Alectoris, Ammoperdix, Aneurophasis, Arborophilia, Bambusicola, Caloperdix, Coturnix, Francolinus, Galloperdix, Haematortyx, Lerwa, Margaroperdix, Melanoperdix, Ophrysia, Perdicula, Perdix, Ptilopachus, Rhizothera, Rollulus, Tetraogallus Tetraophasis, Xenoperdix Subfamily
Phasianinae (Pheasants): Afropavo,
Argusianus, Catreus, Chrysolophus, Crossoptilon, Gallus, Ithiginis, Lophophorus,
Lophura, Phasianus, Pavo, Polyplectron, Pucrasia, Rheinardia, Syrmaticus,
Tragopan. FAMILY MEAGRIDIDAE (SOME SYSTEMS PLACE THESE INTO THE PHASIANIDAE) Miocene to the present. Meleagris. FAMILY TETRAONIDAE (SOME SYSTEMS PLACE THESE INTO THE PHASIANIDAE) Grouse. Terrestrial birds of forests in the cold temperate and subarctic habitats of the Northern Hemisphere. Grouse have compact bodies and medium-sized to moderately large birds (0.30-0.90m) with short legs. They generally are terrestrial but can burst into a short flight. Not migratory. Bonasa,
Centrocercus, Dendragapus, Falcipennis, Lagopus, Tetrao, Tympanuchus. FAMILY ODONTOPHORIDAE Lower Oligocene to the present. Callipepla,
Colinus, Cyrtonyx, Dactylortyx, Dendrortyx, Odontophorus, Oreortyx, Philortyx,
Rhynchortyx. FAMILY NUMIDIDAE Guinea
Fowls. Birds of raiforest to
semi-arid habitats in Acryllium,
Agelastes, Guttera, Numida. FAMILT CRACIDAE Chachalacas,
Curassows, and Guans. Arboreal birds
of tropical Middle Eocene to the present. Subfamily Cracinae (Curassows): Crax, Mitu, Nothocrax, Pauxi. Subfamily
Penelopinae: Aburria, Chamaepetes,
Oreophasis, Ortalis, Penelope, Penelopina, Pipile. FAMILY MEGAPODIIDAE Megapodes.
Birds of tropical forests and semi-arid woodlands in Aepypodius,
Alectura, Eulipoa, Leipoa, Macrocephalon, Megapodius, Talegalla. FAMILY TURNICIDAE Button Quails Turnix ‘WATERBIRD ASSEMBLAGE’ The waterbirds make up another large clade of birds. Eocene to present.
ORDER GRUIFORMES FAMILY EURYPYGIDAE Sunbittern. Eurypyga. FAMILY HELIORNITHIDAE Finfoot. Heliopais,
Heliornis, Podica. FAMILY ARAMIDAE Limpkin.
Wading bird found in freshwater wetlands of temperate South America to Aramus. FAMILY CARIAMIDAE Seriemas. Cariama,
Chunga. FAMILY GRUIDAE Cranes. Wading birds of all continents except South America and Antarctica. They are moderately large to large (0.90-1.76m) and have wingspans of 1.8-2.2m. They have long legs and long necks. Most of them have elaborate displays. Cranes are opportunistic omnivores. Some species are migratory. Subfamily
Balearicinae: Balearica. Subfamily
Gruinae: Anthropoides, Bugeranu, Grus. FAMILY PSOPHIIDAE Trumpeters. Psophia. ORDER RALLIFORMES Rails,
Crakes, and Coots. Birds of
wetlands, but aquatic environments, or terrestrial habitats and with global
distribution; absent only from the |
