Glossary P
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PRIMARY CONSUMER
Primary consumers are plant-eaters (also called herbivores). Most dinosaurs
were plant-eaters.
PRIMITIVE
A primitive form has characteristics similar to those of earlier forms.
PROBACTROSAURUS
(pronounced pro-BACK-troh-SAWR-us) Probactrosaurus (meaning: "before
Bactria lizard") was an early Iguanodontid dinosaur that lived during
the late Cretaceous Period, about 97.5 - 91 million years ago. This plant-eater
was about 17-20 feet (5-6 m) long. This ornithopod had a narrow snout,
an elongated lower jaw, and double layers of flat cheek teeth. Fossils
of this possible ancestor of the duck-billed dinosaurs have been found
in China. The type species is P. gobiensis. Probactrosaurus was named
by Rozhdestvensky in 1966.
PROCERATOPS
(pronounced pro-SER-uh-TOPS) Proceratops (meaning: "before Ceratops")
is an invalid genus. It represents a ceratopsian, a horned, frilled, plant-eating
dinosaur that lived during the late Late Cretaceous Period, roughly 80
to 73 million years ago. Although paleontologist C. O. Marsh found the
first Proceratops fossil in 1888, he named it Proceratops, but it was
actually Ceratops (diagnosed by Richard Swann Lull, of the Peabody Museum,
in 1906). The type species of this invalid genus is P. montanus, now called
Ceratops montanus.
PROCERATOSAURUS
(pronounced pro-ser-RAT-uh-SAWR-us) Proceratosaurus (meaning: "before
horned lizard") was a meat-eating dinosaur that was about 10 feet
(3 m) long, weighing roughly 220 pounds (100 kg). This advanced theropod,
the earliest-known coelurosaur, had a small crest on the very front of
its snout. Because of this crest, it used to be thought that Proceratosaurus
was an ancestor of Ceratosaurus. It had long legs, short arms with long
digits, and a long, stiff tail. This bipedal predator lived during the
middle Jurassic Period, about 170-164 million years ago. Proceratosaurus
is known from a partial fossilized skull found in England. It was named
by paleontologist von Huene in 1926. The type species is C. bradleyi.
PROCESS
A process is a bony projection, like a neural spine.
PROCHENOSAURUS
Prochenosaurus is an invalid genus of dinosaur - see Lambeosaurus.
PROCOLOPHONIDS
Procolophonids are extinct possible ancestors of turtles that had turtle-like
skull features (some scientists think that pareiasaurs are the turtles'
ancestors). These reptiles lived from the late Permian (about 260 million
years ago) until the late Triassic Period (about 210 million years ago).
These amniotes were early anapsids, a type of cotylosaurian (captorhinid).
Fossils have been found in South Africa and Russia. When the procolophonids
went extinct at the end of the Triassic period, the turtles were the only
remaining anapsids.
PROCOMPSOGNATHUS
(pronounced pro-komp-SOG-na-thus) Procompsognathus us (meaning: "before
pretty jaw from the Triassic period") was a small, speedy theropod
dinosaur (an early ceratosaur) from the late Triassic Period, about 222
to 219 million years ago. This carnivorous biped had long hind legs, short
arms, large hands (which it used to catch prey), a long pointed snout
with many pointed teeth, and a stiff, pointed tail. It may have been about
3.8 feet (1.2 m) long, weighing roughly 2.2 pounds (1 kg). It probably
ate insects and lizards in a relatively dry, inland environment. A very
incomplete skeleton was found in Württemberg, Germany. It was named
by Eberhard Fraas in 1913.
PRODEINODON
(pronounced pro-DIEN-oh-don ) Prodeinodon (meaning: "before Deinodon")
was a theropod dinosaur (perhaps a tyrannosaurid) from the mid-late Cretaceous
Period. Scanty fossils of this carnivorous biped were found in the Gobi
Desert in Mongolia, China. Prodeinodon was named by Osborn in 1924. The
type species is P. mongoliensis. Prodeinodon is a dubious genus.
PRODUCER
A producer (or aurotroph) is an organism that makes its own food from
light energy (using photosynthesis), or chemical energy (using chemosynthesis).
Most green plants, many protists (one-celled organisms like slime molds
and amoebas) and most bacteria are producers. Producers are the base of
the food chain.
PROGANOCHELYS
Proganochelys is the oldest known turtle, dating from the late Triassic
Period, evolving about 210 million years ago, only a little before the
dinosaurs and mammals evolved. This anapsid was about 2 feet (60 cm) long,
had a shell (formed by fused ribs and other bones), was an omnivore, had
no teeth, and had a large ear-opening. It had protective spikes on its
neck, which could not retract. It probably couldn't pull its other appendages
into its shell for protection either (like later turtles could). It had
a relatively long tail equipped with bony spikes and a tail club. It lived
near ponds and other small bodies of water, but was probably primarily
terrestrial. Fossils have been found in Germany and Thailand.
PROIGUANODON
(pronounced pro-ig-WAN-oh-don) Proiguanodon (meaning: "first or before
Iguanodon") was an iguanodontid dinosaur discovered by van den Broeck
in 1900. This thumb-spiked plant-eater had hoof-life feet and a toothless
beak. It lived during the Cretaceous Period. Proiguanodon was named by
van den Broeck in 1900.
PROSAUROLOPHUS
(pronounced PROH-saw-ROL-oh-fus) Prosaurolophus (meaning: "before
Saurolophus" since it may have been an ancestor of Saurolophus) was
a duck-billed dinosaur (it was an early hadrosaurine hadrosaur). It dates
from the Cretaceous Period, about 77 to 73 million years ago. This plant-eater
was about 26 feet (8 m) long, had a flat head with no crest, a large,
long skull, a toothless beak, and cheek teeth. Fossils were found in Alberta,
Canada. Prosaurolophus was named by Brown in 1916. The type species is
P. maximus.
PROSAUROPODA
(pronounced proh-sawr-OP-oh-da) The prosauropods (meaning: "before
sauropoda [lizard-footed]") were an infraorder of the sauropodomorpha
dinosaurs and were either the ancestors of the sauropods or had a common
ancestor with them. Prosauropods had a long neck, a small head, and large,
hooked claws on their 5-toed feet; they had a reduced fifth metatarsal
(toe). They ranged in size from 8-40 feet (2.4-12 m) long, and lived from
the mid Triassic Period to the early Jurassic Period. The earliest-known
sauropodomorph is a prosauropod about 230 million years old. The earliest
prosauropods were semi-quadrupedal (able to walk on two or four legs)
and were omnivores with knife-like teeth and light bones. Later prosauropods
were heavier, quadrupedal and herbivore. Prosauropods include the families:
Anchisauridae, Massospondylidae, Melanorosauridae, Plateosauridae, etc.
Prosauropod
A group of early lizard-hipped dinosaurs that appeared during the Triassic
period and died out during the Jurassic period. The group included Plateosaurus
and was closely related to the gigantic sauropods such as Diplodocus.
PROTARCHAEOPTERYX
Protarchaeopteryx (meaning: "early ancient wing") was a bird-like,
non-flying, meat-eating dinosaur that had symmetrical feathers (asymmetrical
feathers are needed for flight). The feathers covered its arms, most of
the body and the short tail. The feathers ranged from downy to structured
quills with shafts and veins. It dates from about 128-110 million years
ago during the Cretaceous Period, had long legs, short arms, and was the
size of a turkey. It lacked the typical theropod long tail but had a fan
of tail feathers. Fossils have been found in the sediment of an ancient
lake bed in China's Liaoning Province.
PROTEROZOIC
The Proterozoic (also called the Cryptozoic) was an eon in geological
time that lasted from 2.5 billion years ago to 540 million years ago.
During the Proterozoic Eon, the first multicellular life evolved, including
colonial algae, solf-bodied invertebrates, and sponges.
Protoanthus
It is a made up name to describe the earliest flowers which evolved in
the Early Cretaceous period.
PROTOAVIS
Protoavis (meaning: "first bird") is an extinct diapsid from
the late Triassic Period (80 million years earlier than Archaeopteryx).
Its partly toothless jaw and keel-like breast bone were like those of
birds. It also had a tail, dinosaur-like rear legs, and hollow bones.
There is some dispute about whether this animal was a bird (which would
make it the earliest-known bird) or a theropod dinosaur; the answer depends
partly on whether the Protoavis fossil belongs to two different genera
(a chimera) or one (a valid genus). Fossils of this carnivore have been
found in Texas, USA. Protoavis was named by Chatterjee in 1991. The type
species is P. texensis.
Protoceratops
(pronounced PRO-toh-SER-ah-tops) Protoceratops (meaning: "first horned
face") was a small, frilled, plant-eating dinosaur up to 6 feet long
(1.8 m), weighing about 900 pounds (400 kg). This ceratopsian lived in
the late-Cretaceous Period, about 86 to 71 million years ago in what is
now Mongolia. Eggs and dozens of fossilized skeletons have been found.
It was named by Granger and Gregory in 1923. The type species is P. andrewsi.
PROTOHADROS
(pronounced PRO-toe-HAD-ros) Protohadros (meaning: "first hadrosaur")
is the oldest-known duck-billed dinosaur, dating from about 95 million
years ago, during the Cretaceous Period, and seems to indicate a North
American origin for hadrosaurs. Protohadros was a large, plant-eating,
duck-billed dinosaur with relatively large, deep jaws. Its fossils were
found in 1994 in North Central Texas (the Cenomanian Woodbine Formation),
USA. Protohadros was named by paleontologist Jason J. Head in 1988, and
was found by Gary Byrd (an amateur paleontologist). The type species is
P. byrdi.
PROTOSUCHUS
(pronounced PRO-toh-SOOK-us) Protosuchus (meaning: "first crocodile")
was a primitive terrestrial crocodile that lived during the early Jurassic
Period, roughly 200 million years ago. This carnivore (meat-eater) had
a long tail, a large, wide, short skull with powerful jaws and many large,
dagger-like teeth. On the lower jaw, two large teeth extended past the
other teeth and fit into notches in the upper jaw. The rear legs were
longer than the front legs. It had five-toed, clawed feet. Protosuchus
was about 3 feet (1 m) long. Fossils of this meat-eater have been found
in Arizona, USA, North America. Protosuchus was not a dinosaur; it was
an early crocodilian.
PROTOZOA
Protozoans (meaning: "first animals") are a phylum of primitive
animals that include the following classes: Mastigophora (flagellates),
Sarcodina (amoebas), Sporozoa (Parasites), and Ciliata (Ciliates).
PROXIMAL
Proximal means closest from the point of attachment to the body (compare
with distal, its opposite).
PSEUDOFOSSIL
A pseudofossil is false or fake fossil. Sometimes minerals (like manganese
oxide) can discolor rocks naturally and the result is a fossil-like impression.
Some pseudofossils are fake fossils manufactured by people.
PSEUDOTETRASAUROPUS
Pseudotetrasauropus was a lightly-built bipedal prosauropod dinosaur that
is is known only from its five-toed fossilized tracks. This primitive
plant-eating ichnogenus lived from the late Triassic Period to the Early
Jurassic Period and had a broad range in what is now North America.
PSITTACOSAURUS
(pronounced SIT-ah-co-SAWR-us) Psittacosaurus (meaning: "parrot lizard")
was a small, very primitive ceratopsian. This fast-moving plant-eater
had a narrow, horny beak with no teeth, and cheek teeth towards the rear
of the mouth. It had a boxy skull with short, horn-like projections on
the cheeks. It had four long fingers on each hand; the arms were much
shorter than the legs. Psittacosaurus could walk on two or four legs.
Psittacosaurus was about 5.6 feet (2 m) long and weighed about 50 pounds
(25 kg). It lived from 119-97.5 million years ago during the early Cretaceous
Period. Fossils have been found in Mongolia, China, and Thailand. It was
named by paleontologist Henry F. Osborn in 1923. The type species is Psittacosaurus
mongoliensis.
PTERANODON
(pronounced ter-AN-oh-don) Pteranodons were large, Cretaceous period pterosaurs,
flying prehistoric reptiles. They were not dinosaurs. They were toothless
hunters who scooped up fish from the seas. They were named by paleontologist
O. Marsh in 1876.
Pteridophyte
A major division of plants that includes primitive vascular groups such
as the ferns, horsetails and clubmosses. All three of these share a common
history, originating in the Devonian period. For sexual reproduction,
all pteridophytes require the presence of standing water and the new plant
can only grow at the site of fertilization. Thus they are uncommon in
environments that are dry all year-round, or strongly seasonal.
PTERIDOSPERMS
Pteridosperms (Seed ferns) were primitive seed plants (not ferns at all)
that lived in swampy areas from the Mississipian Epoch through the Mesozoic
Era. They had woody stems studded with dried out leaf bases. The tops
had fern-like fronds which bore seeds. Some seed ferns include Glossopteris
(pictured above), Dicroidium, Caytonia, Denkania, and Lidgettonia.
PTERODACTYLS
(pronounced ter-oh-DAK-tils) Pterodactyls or pterodactyloids (meaning:
"winged finger") were flying, prehistoric reptiles. They were
a subgroup of pterosaurs and were not dinosaurs.
PTERODACTYLUS
(pronounced ter-oh-DAK-til-us) Pterodactylus (meaning: "wing finger")
was a pterosaur with a 2.5 foot (0.75 m) wide wingspan. Its head contained
long, narrow jaws and sharp teeth, but it had no head crest on top. It
is known to have lived in what is now Tanzania, England, France, and Germany
during the late Jurassic Period. It was not a dinosaur, but type of extinct,
flying reptile that lived during the late Jurassic Period. It reproduced
by laying eggs. Pterodactylus was named by Rafinesque in 1815.
PTERODAUSTRO
Pterodaustro (meaning: "southern wing") was a pterosaur with
a 4 foot (1.2 m) wide wingspan. Its jaws were very long, thick, and blunt,
with long teeth in the lower jaw and tiny teeth in the upper jaw. It may
have gathered food by skimming it from the ocean surface. It was from
what is now Argentina during the late Jurassic Period. It was not a dinosaur,
but a related, extinct, flying reptile that lived during the eaerly Cretaceous
Period. It was named by paleontologist J. Bonaparte 1969.
pterosaur
(pronounced TER-o-SAWR) Pterosaurs (meaning: "winged lizard")
were flying, prehistoric reptiles. They were not dinosaurs, but were closely
related to them. Pterosaurs were named by Kaup in 1834.
PTERYGOTUS
Pterygotus was an Eurypterid, an extinct "sea scorpion." This
ancient marine arthropod (a segmented invertebrate with a chitinous exoskeleton
and jointed legs) was over 6.5 ft (2 m) long. One specimen in NY, USA
was 9 ft (2.75 m) long. These hunters had a scorpion-like stinger which
may have contained poison, 3 pairs of jointed legs, 2 clawed arms, 2 paddles,
and strong jaws. They may have swum on their backs. This fierce hunter
lived in the seas during the Silurian period, over 400 million years ago.
PUBIS
The pubis is a bone that is part of the hip, or pelvic girdle. It points
downwards and slightly towards the front in saurischians (theropods and
sauropods) and downwards and towards the tail in ornithischians.
PUNCTUATED EQUILIBRIA
Punctuated equilibria is a theory that addresses the rate of evolutionary
change over time. In this theory, long periods of relatively little evolutionary
changes are followed by bursts of rapid evolutionary changes in which
new species appear. Punctuated equilibria was described by Niles Eldredge
and Stephen Jay Gould (1972). (Also see phyletic gradualism.)
PYRORAPTOR
Pyroraptor (meaning: "fire thief"; given this name because it
was found after a forest fire) was a meat-eating dinosaur that lived during
the late Cretaceous period. A very incomplete skeleton of this deinonychosaur
(an advanced theropod) was found in France. Pyroraptor may be the same
as Variraptor. Pyroraptor was named by Allain and Taquet in 2000. The
type species is P. olympius.