Glossary P
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PARACERATHERIUM
Paraceratherium (similar to Indricotherium) is a large, extinct, hornless
rhinoceros. It was one of the largest land mammals. Adults were about
26 feet (8 m) long, 18 feet (5.5 m) tall, and weighed about 15-20 tons.
The skull was 4.25 feet (1.3 m) long. This herbivore ate leaves and twigs
from the tops of trees. It had four teeth; two tusk-like front teeth in
the top jaw, pointing down and two on the bottom pointing forwards. This
extinct ungulate (hoofed mammal) had three toes on each foot and lived
from the Oligocene to the early Miocene (roughly 30 million years ago)
in central Asia (Pakistan, Mongolia and China). Paraceratherium was first
found by English paleontologist C. Forster Cooper in Pakistan in 1910.
Classification: Order Perissodactyla (odd-toed ungulates), Family Hyrachyidae
(odd-toed ungulates between tapirs and rhinos).
PARALITITAN
Paralititan (meaning: "tidal Titan") was a huge titanosaurid
sauropod that lived during the middle Cretaceous Period, about 100 million
years ago. This plant-eating dinosaur had a long neck, small head, bulky
body, and long tail. It was about 78-100 ft long (24-30 m long) and weighed
perhaps 70 tonnes. Fossils were found in Bahariya Oasis, Egypt. Paralititan
was named by Joshua B. Smith, Lamanna, Lacovara, Dodson, Smith, Poole,
Giegengack and Attia in 2001. The type species is P. stromeri (2001, named
to honor Ernst Stromer von Reichenbach, a German paleontologist and geologist
who found dinosaurs in this area in the early 1900's).
PARAPATRIC SPECIATION
Paripatric speciation (the formation of new species) occurs when a population
enters a new habitat or niche within the same geographical area of the
parent species, but becomes reproductively isolated from the parent species.
Compare with allopatric speciation and sympatry.
PARAPATRY
Paripatry means occupying overlapping geographic locations. Compare with
allopatry and sympatry.
PARAPHYLETIC GROUP
A paraphyletic group (also called a grade) consists of a common ancestor
and some, but not all, of its descendants. These are incomplete groups
based primarily on physical characteristics rather than directly on evolutionary
relationships. An example of a paraphyletic group is the dinosaurs (without
including the birds).
PARA-SACRAL SPINES
Para-sacral spines are bony spikes that extend from the hip area in stegosaurs
(like Stegosaurus and Kentrosaurus).
PARASAUROLOPHUS
(pronounced PAR-ah-saw-ROL-oh-fus) Parasaurolophus was a long-crested,
duck-billed dinosaur from the late Cretaceous Period. This beaked plant-eater
was about 33 feet (10 m) long. The type species is P. walkeri; it was
named by Parks in 1922.
PARASITE
A parasite is an organism (a plant or animal) that lives on another organism
(the host), obtaining nutrition from it and sapping or killing the host.
PARASITISM
Parasitism is arelationship between two organisms in which one organism
benefits at the other organism's expense. Lice are an example of a parasite
that affects many animals; termites are a parasite that are destructive
to many trees. Parasitism is a type of symbiosis.
PARATYPE
A paratype is all of the specimens of the type series of a species or
subspecies other than the holotype.
PAREIASAUR
Pareiasaurs are close relatices of turtles (they may be the ancestors
of turtles, but many scientists think that procolophonids are the turtles'
ancestors). These herbivores (plant-eaters) had polygonal bony scales
(scutes) on their body that acted as armor (these scutes may have evolved
into the turtle's shell). They had iguana-like teeth, a bulky body, four
short legs, a box-like skull, and a short, pointed tail. They include
the biggest terrestrial anapsids that ever lived; they were up to about
7.5 ft (2.5 m long). These reptiles lived during the late Permian (about
260 million years ago) and probably went extinct during the Permian mass
extinction. These amniotes were early anapsids. Fossils have been found
in Europe, Asia, and Africa. Some Pareiasaurs include Bradysaurus, Scutosaurus,
and Anthodon.
PARKS, WILLIAM A.
William Arthur Parks (1868-1939) was a Canadian paleontologist who described
Arrhinoceratops (1925), Dyoplosaurus (1924), Lambeosaurus (1923), and
Parasaurolophus (1923). Parksosaurus was named by paleontologist Chas.
M. Sternberg in 1937 to honor Parks.
PARKSOSAURUS
(pronounced PARK-soh-SAWR-us) Parksosaurus (meaning: "[William Arthur
Parks (1868-1939), a Canadian paleontologist] Parks' lizard") was
a small, plant-eating dinosaur from the late Cretaceous period, about
68-65 million years ago. This biped was about 7 ft (2 m) long, weighing
roughly 150 pounds (70 kg). It had a long tail, strong arms, a long neck,
and short toes. Parksosaurus had a small head with wide jaws and unique
teeth (they had low, rounded ridges). Incomplete fossils of this hypsilophodontid
ornithopod has been found in Alberta, Canada and Montana, USA. Parksosaurus
was named by paleontologist Chas. M. Sternberg in 1937. The type species
is P. warrenae.
PARONYCHODON
(pronounced parr-oh-NYE-co-don) Paronychodon (meaning: "near claw
tooth") was a small, meat-eating dinosaur that lived during the late
Cretaceous Period, about 73-65 million years ago. This advanced theropod
is known only from non-serrated teeth found in Montana, New Mexico, and
Wyoming, USA. Paronychodon was named by paleontologist E. D. Cope in 1876;
the type species is P. lacustris. Paronychodon is a dubious genus since
only fossils teeth have been found; it may be the same as Troodon or another
troodontid.
PARROSAURUS
(pronounced PARR-oh-SAWR-us) Parrosaurus (meaning: "Parr lizard,
honoring Albert Eide Parr, an American zoologist") is an invalid
name for Hypsibema, an ornithopod dinosaur (probably a duckbill, but only
a few bones have been found) from the late Cretaceous period, about 83-73
million years ago. Parrosaurus missouriensis was named by paleontologist
Charles W. Gilmore in 1945.
PARSIMONY
Parsimony is the scientific idea that the simplest explanation of a phenomenon
is the best one.
PATAGONYKUS
(pronounced pat-ah-GONE-eh-kus) Patagonykus (meaning: "Patagonia
claw") was a lightly-built meat-eater with a single, clawed finger
on each hand. It was about 6.5 ft (2 m) long. It had long legs, a long
tail, and short arms. Patagonykus lived during the late Cretaceous Period,
about 90 million years ago. Patagonykus was either a bird-like dinosaur
(an advanced theropod, or a primitive bird; it possessed qualities of
both groups of animals, and there is much scientific debate over which
it is. Patagonykus was similar to Mononykus. Fossils were found in Patagonia,
a region of southern Argentina. The type species is P. puertai. Patagonykus
was named by paleontologist F. Novas in 1996.
PATAGOSAURUS
(pronounced PAT-a-go-SAWR-us) Patagosaurus (meaning: "Patagonian
or big-footed lizard") was a large, quadrupedal, plant-eating dinosaur
from the middle Jurassic Period, about 169-163 million yeas ago. This
cetiosaurid, a primitive sauropod, was about 65 feet (20 m) long; it had
a small head, a long neck, and a long tail. Patagosaurus was found in
Patagonia, in southern Argentina. Patagosaurus is similar to the European
dinosaur Cetiosaurus, and lends support to the theory of continental drift,
and South America and Europe being connected during the Jurassic period.
Patagosaurus was named by Bonaparte in 1979. The type species is P. fariasi.
PAWPAWSAURUS
(pronounced paw-paw-SAWR-us) Pawpawsaurus (meaning: "paw-paw formation
lizard") was a large, armored, quadrupedal, plant-eating dinosaur
from the middle Cretaceous period, about 97 million yeas ago. This nodosaurid
ankylosaur had bony eyelids and armor over most of its body (it did not
have a tail club). Incomplete fossils have been found in Tarrant County,
Texas. Pawpawsaurus was named by Yuong-Nam Lee in 1996. The type species
is P. campbelli (C. Campbell discovered the fossil).
PECTINODON
(pronounced peck-TIN-oh-don) Pectinodon (meaning: "comb tooth")
was a meat-eating dinosaur from the late Cretaceous period, about 73-65
million yeas ago. Pectinodon was named by Carpenter in 1982. The type
species is P. bakkeri. Pectinodon is an invalid genus - see Troodon.PEISHANSAURUS
(pronounced PAY-shan-SAWR-us) Peishansaurus (meaning: "Peishan [China]
lizard") was a plant-eating dinosaur that lived during the late Cretaceous
period, roughly 97.5-65 million years ago. Peishansaurus was named by
Bohlin in 1953 from a fragmentary jaw with some teeth (found in China).
The type species is P. philemys. Peishansaurus is a doubtful genus; it
is either an an ankylosaur armored dinosaur) or a pachycephalosaur (thick
skulled dinosaur).
PELECANIMIMUS
(pronounced PEL-uh-kan-uh-MEEM-us) Pelecanimimus (meaning: "pelican
mimic") was a meat-eating dinosaur from the early Cretaceous Period,
roughly 132-121 million years ago. Pelecanimimus is the first ornithomimosaur
discovered in Europe. It had about 220 teeth, more than any other known
theropod. It was about 6.5 ft (2 m) long. It had a dewlap (a loose fold
of skin hanging from the chin) and a head crest made of skin. Fossils
have been found in found in Las Hoyas, Cuenca, Spain, including a skull,
partial skeleton, and some skin and muscle impressions (which were originally
though to be feathers). Pelecanimimus was named by paleontologists Perez-Moreno,
Sanz, Buscalloni, Moratalla, Ortega, and Rasskin-Gutman in 1994. The type
species is P. polyodon, polyodon meaning: "many teeth."
PELONEUSTES
Peloneustes was a plesiosaur 10 feet (3 m) long with a big head, streamlined
body, long head, and relatively few, not very sharp teeth. Fossilized
stomach containing suckers from cephalopods (e.g., squids) have been found.
From England and eastern Europe during the late Jurassic period. It was
not a dinosaur, but another type of extinct reptile.
PELOROSAURUS
(pronounced pe-LOW-roh-SAWR-us) Pelorosaurus (meaning: "monstrous
lizard") was one of the first sauropod dinosaurs ever discovered.
This long-necked plant-eater was about 80 feet (24 m) long. It was a quadruped
(it walked on four sturdy legs). It lived during the early Cretaceous
Period, about 138 to 97 million years ago. Its classification is unsure
and the genus status is doubtful; it may have been a Brachiosaurid (related
to Brachiosaurus) or a titanosauroid (related to Andesaurus). Pelorosaurus
is known from very incomplete skeletons and fossilized skin impressions
from the Wealden Formation in England and a from a single forelimb bone
found in Fervenca, Portugal. Pelorosaurus was named by the famous fossil
hunter Gideon Mantell in 1850. The skin impression showed hexagonal (six-sided)
plates that were 9-26 mm across. The type species is P. conybearei.
PELYCOSAUR
Pelycosaurs (meaning: "basin lizards") were the earliest synapsids;
they were not dinosaurs. These quadrupeds appeared during the upper Carboniferous
and went extinct during the Permian period (before the Triassic Period
when the dinosaurs evolved). Pelycosaurs began as small, lizard-like animals
and evolved into larger, more differentiated types. Some were carnivores,
some were herbivores; some had sailbacks like Dimetrodon), some did not.
These swamp dwellers with a sprawling gait were likely the ancestors of
the therapsids, which led to the mammals. Pelycosaurs are divided in to
the suborders Eupelycosauria and Caseasauria.