Glossary ALE - ALX
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ALECTROSAURUS
(pronounced ah-LECK-troh-SAWR-us) Alectrosaurus [meaning: "Alectra's
lizard," Alectra was one of the furies in classical mythology] was
a huge, bipedal, meat-eating dinosaur from the late Cretaceous period,
about 98 million to 88 million years ago. It was a tyrannosaurid, a theropod
related to Tyrannosaurus rex, but it had larger arms and claws and very
long jaws with many teeth. Unlike most tyrannosaurids, its skull was smooth
on top. It was about 25-30 feet (8-9 m) long and weighed perhaps 1.5 tons.
It had powerful legs, tiny arms, and a stiff, pointed tail. Partial skeletons
have been found in the Gobi Desert in Mongolia. Alectrosaurus was named
by paleontologist C. W. Gilmore in 1933. The type species is A. olseni.
Algae
Simple plants made of basic cells either alone or in long chains. In large
quantities it appears as a water plant with no stem or leaves. The most
familiar larger algae are seaweeds.
ALGOASAURUS
(pronounced al-GOH-a-SAWR-us) Algoasaurus (meaning: "Algoa Bay (South
Africa) lizard") is doubtful genus of dinosaurs; it is known from
only a few bones found in Africa. This long-necked, long-tailed plant-eater
(a neosauropod and perhaps a titanosaurid) was about 30 ft (9 m) long.
It lived during the early Cretaceous period, about 145-135 million years
ago. The type species is A. bauri. Algoasaurus was named by the paleontologist
Broom in 1904.
ALIORAMUS
(pronounced AL-ee-uh-RAY-mus) Alioramus, meaning: "different branch,"
was a large, bipedal, meat-eating dinosaur from the late Cretaceous period,
about 73 million to 65 million years ago. It was a tyrannosaurid theropod
about 16-20 feet (5-6 m) long, perhaps weighing up to 1 ton. It had 6
tiny horns on its snout; four in a row on the lower snout plus a horizontal
pair near the eyes. It had powerful legs, tiny arms, and a stiff, pointed
tail. It had more teeth and a longer skull than other tyrannosaurids.
A single, fragmentary skeleton was found in Mongolia. Alioramus was named
by Kurzanov in 1976. The type species is A. remotus.
ALIWALIA
(pronounced ahl-ih-WAHL-ee-ah) Aliwalia (named for Aliwal North, South
Africa) was a carnivorous dinosaur known from only a few bones found in
south Africa. This meat-eater (a theropod) was about 25 ft (8 m) long
and weighed about 1500 kg. It lived during the late Triassic Period, about
145-135 million years ago. The type species is A. rex. Aliwalia was named
by the paleontologist Galton in 1985. The type species is A. rex.
ALLIGATOR
Alligators are large reptiles. Primitive alligators evolved during the
late Triassic period.
ALLOPATRIC SPECIATION
Allopatric speciation is the formation of new species after a population
has been separated geographically. Over time, the two isolated populations
diverge genetically. Allopatric speciation is probably the major mode
of speciation (the formation of new species). Compare with parapatric
speciation and sympatry.
ALLOPATRY
Allopatry means occupying different geographic locations. Compare with
parapatry and sympatry.
ALLOSAURUS
Allosaurus had a large powerful jaw with long, sharp, serrated teeth 2
to 4 inches long. These teeth were curved inward, shaped like a"D"
to help secure its pray. It had a massive tail, a bulky body, and thick
bones. Its arms were short and had three fingered hands with sharp claws
that were up to 6 inches long.
ALOCODON
(pronounced a-LOK-oh-don) Alocodon (meaning: "furrowed tooth")
is doubtful genus of dinosaurs; it is known from only a single tooth.
Alocodon was a small, plant-eating dinosaur of unknown length, perhaps
about about 3 feet (1 m) long. It was an ornithischia from Europe (Portugal)
during the late Jurassic Period, about 164 million years ago. The type
species is A. kuehni. Alocodon was named by the paleontologist Thulborn
in 1973.
ALPHADON
(pronounced AL-fa-don) Alphadon (meaning: "first tooth") was
a metatherian, primitive marsupial. It was not a dinosaur, but lived with
the dinosaurs. Alphadon was a small omnivore, eating fruit, insects, and
small animals. It was about 1 feet (30 cm) long. This tree-dweller had
opposable toes and a prehensile tail which it may have used to climb trees.
It lived in North America (Alberta, Canada to New Mexico, USA) during
the late Cretaceous Period, about 70 million years ago. The type species
is A. marshi. Alphadon was named by the paleontologist Simpson in 1929.
Classification: Subclass Prototheria, Order Pantotheria, Infraclass Metatheria,
Genus Alphadon.
ALTICAMELUS
Alticamelus (meaning: "tall camel") is the old name of Aepycamelus.
It was a prehistoric camel that lived from the middle through late Miocene.
This giraffe-like early camel was about 10 ft (3 m) tall at the head;
it had a small back hump and a short tail. It had very long legs, and
small hooves on its two toes and broad pads. It probably moved in a manner
similar to modern-day camels. Fossils of this mammal have been found in
Colorado, USA.
ALTIRHINUS
(pronounced al-ti-RINE-us) Altirhinus (meaning: "high snout")
was an iguanodontid, a plant-eating dinosaur about about 23-26 feet (7-8
m) long. Altirhinus had a tall beak on its rounded snout and a spiked
thumb on each hand. This big-nosed dinosaur may have had a good sense
of smell. It walked on two long legs but could also eat on all four imbs
- the arms were a bit smaller than the legs. It was an ornithischia from
Mongolia during the early Cretaceous Period. The type species is A. kurzanovi.
Altirhinus was named by the paleontologist David Norman in 1998. Altirhinus
used to be known as Iguanodon bernissartensis, (Rozhdestvensky, 1952).
ALTISPINAX
(pronounced AL-tee-SPY-nax) Altispinax (meaning: "high spine")
is doubtful genus of dinosaurs; it is known from only a single tooth.
The vertebral material originally found (which gave this dinosaur its
name) has been assigned the name Becklespinax. Altispinax was a large
meat-eating dinosaur of unknown length, perhaps about about 30 feet (9
m) long, weighing roughly 1000 kg. It was a theropod, a bipedal, meat-eating,
stiff-tailed predator from Europe (England) during the early Cretaceous
Period, about 123-119 million years ago. The type species is A. dunkeri.
Altispinax was named by the paleontologist von Huene in 1923.
ALVAREZ, LUIS
Luis Alvarez (1911-1988) was a physicist who, with his son Walter Alvarez
(a geologist), hypothesized that the a huge asteroid hit Earth the Earth
65 million years ago, causing a mass extinction. The Alvarez Theory of
Extinction is widely accepted. Luis Alvarez received a Nobel Prize in
physics (1968) for his work on subatomic particles.
ALVAREZ THEORY OF EXTINCTION
This theory is that a large asteroid, meteor, or comet hit the Earth 65
million years ago, causing huge atmospheric and geologic disruptions,
leading to a mass extinction which killed the dinosaurs and many other
species.
ALVAREZSAURUS
(pronounced Al-vuh-rez-SAWR-us) Alvarezsaurus was a small, lightly-built,
bird-like, bipedal theropod (a meat-eating dinosaur) that was about 6
feet (2 m) long, weighing roughly 20 kg. This fast runner had very long
legs, long feet, very short arms, a long, s-shaped neck, and an extremely
long, thin, flat tail. The tail was over half of the dinosaur's length.
It had no ridges on its back, like most other theropods. It lived during
the late Cretaceous Period, 80 million years ago, in what is now Argentina.
It and the family of Alvarezsaurids were named for the historian Don Gregorio
Alvarez by José Bonaparte in 1991. The type species is A. calvoi.
ALWALKERIA
(pronounced al-wah-KEER-ee-a) Alwalkeria was a small, early theropod (a
bipedal, meat-eating dinosaur). It lived during the late Triassic Period,
roughly 220 million years ago. An incomplete fossil was found in what
is now India. It was named by Chatterjee and Creisler in 1994, honoring
the British vertebrate paleontologist Alick D. Walker. The type species
is A. maleriensis.
ALXASAURUS
(pronounced AWL-shah-SAWR-us) Alxasaurus (meaning: "Alxa [Desert
of Inner Mongolia] lizard") was an advanced theropod (a meat-eating
dinosaur) that was about 11.5-13 feet (3.5-4 m) long and weighed about
800-900 pounds (350 to 400 kg). This bipedal carnivore had long legs with
clawed feet, relatively long arms, a long, s-shaped neck, a toothless
beak, and a short tail. Alxasaurus was the most primitive therizinosauroid
(bird-like asian theropods with unusual feet). It lived during the Cretaceous
Period, about 99 million years ago, in what is now Mongolia. It was named
by paleontologists D. A. Russell and Dong in 1995. The type species is
A. elesitaiensis.