Titanosaur
Encyclopedia
Titanosaurs were a diverse group of sauropod
dinosaur
s, which included Saltasaurus
and Isisaurus
. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus
and Paralititan
— which some believe have weighed up to 100 tonne
s (110 short ton
s). Consequently, they were named titanosaurs in honor of the mythological
Titans
, the early deities
of Ancient Greece
. Together with the brachiosaurids
and relatives, they make up the larger clade
Titanosauriformes.
and Brachiosaurus
but more elongated. Their nostrils were large ('macronaria
n') and they all had crests formed by these nasal bones. Their teeth were either somewhat spatulate (spoon-like) or like pegs or pencils, but were always very small.
Their necks were relatively short, for sauropods, and their tail
s were whip-like, but not as long as in the diplodocid
s. While the pelvis
(hip area) was slimmer than some sauropods, the pectoral (chest area) was much wider, giving them a uniquely 'wide-gauged' stance. As a result, the fossilised trackways
of titanosaurs are distinctly broader than other sauropods. Their forelimbs were also stocky but their rear limbs were longer. Their vertebrae (back bones) were solid (not hollowed-out), which may be a throwback to more primitive saurischia
ns. Their spinal column was more flexible, so they were probably more agile than their cousins and better at rearing up.
From skin impressions found with the fossil
s, it has been determined that the skin of many titanosaur species was armored
with a small mosaic of small, bead-like scales
around a larger scale. One species, Saltasaurus
, has even been discovered with bony plates, like the Ankylosaurs.
While they were all huge, many were fairly average in size compared with the other giant dinosaurs. There were even some island-dwelling dwarf species such as Magyarosaurus
, probably the result of allopatric speciation
and insular dwarfism
.
Derived titanosaurs had biconvex vertebrae. The primitive condition is either amphiplaty or amphicoely. Venenosaurus
may have had a condition intermediate between the two.
, about 90–65 million years ago and were the dominant herbivore
s of their time. The fossil evidence suggests they replaced the other sauropods, like the diplodocid
s and the brachiosaurids, which died out between the late Jurassic
and the mid-Cretaceous
Periods.
Titanosaurs were widespread. Fossils have been found on all continents except Antarctica. Four well preserved skeletons of a titanosaur species were found in Italy
, a discovery first reported on May 2, 2006. They are especially numerous in the southern continents (then part of the supercontinent
of Gondwana
). Australia had titanosaurs around 96 million years ago: fossils have been discovered in Queensland
of a creature around 25 meters long (82 feet). Remains have also been discovered in New Zealand.
associated with late Cretaceous titanosaurids has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycad
s and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledon
s, including palm
s and grasses (Poaceae
), including ancestors of rice
and bamboo
, which has given rise to speculation that herbivorous dinosaurs and grasses co-evolved
.
ing ground was discovered in Auca Mahuevo, in Patagonia
, Argentina
and another colony has reportedly been discovered in Spain
. Several hundred female saltasaurs
dug holes with their back feet, laid eggs in clutches averaging around 25 eggs each, and buried the nests under dirt and vegetation. The small egg
s, about 11–12 cm (4–5 in) in diameter
, contained fossil
ised embryo
s, complete with skin
impressions. The impressions showed that titanosaurs were covered in a mosaic armour of small bead-like scales. The huge number of individuals gives evidence of herd
behavior, which, along with their armour, could have helped provide protection against large contemporary predators such as Abelisaurus
.
-dwelling herbivore
s, has been disappointingly fragmentary for such a widespread and successful group (they represent roughly a third of the total sauropod diversity known to date). Only recently have skulls or relatively complete skeletons (see Rapetosaurus
) of any of the roughly 50 species
of titanosaur been discovered. Many species are poorly known. Much material may be reclassified and some genera renamed as understanding of the clade
grows.
The family Titanosauridae was named after and anchored on the poorly known genus Titanosaurus
, which was coined by Richard Lydekker
in 1877, on the basis of a partial femur and two incomplete caudal vertebrae. Fourteen species have since been referred to Titanosaurus, which distribute the genus across Argentina
, Europe
, Madagascar
, India
and Laos
and throughout 60 million years of the Cretaceous Period. Despite its centrality to titanosaur systematics and biogeography, a re-evaluation of all Titanosaurus species recognises only five as diagnostic. The type species T. indicus is invalid, because it is based on 'obsolescent' characters - once diagnostic features that have gained a broader taxonomic distribution over time. Consequently, use of the genus Titanosaurus has largely been abandoned. The most well known Titanosaurus specimens have since been re-assigned to other genera, including Isisaurus
.
Some paleontologists (such as Sereno
, 2005 ) have contended that Titanosaurus is too poorly known to use as a basis for classification, family names for which it is the type genus (e.g. Titanosaurinae, Titanosauridae, Titanosauroidea) should not have other genera referred to them. Weishampel et al., in the second edition of The Dinosauria, also did not use the family Titanosauridae, and instead used several smaller titanosaur families such as Saltosauridae and Nemegtosauridae.
Relationships within the Titanosauria have historically been extremely variable from study to study, complicated by the fact that clade and rank names have been applied inconsistently by various scientists. One possible cladogram
is presented here, and follows a 2007 analysis by Calvo and colleagues. The authors notably used the family Titanosauridae in a broader fashion than other recent studies, and coined the new clade name Lognkosauria.
Sauropoda
Sauropoda , or the sauropods , are an infraorder of saurischian dinosaurs. They had long necks, long tails, small heads , and thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s, which included Saltasaurus
Saltasaurus
Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...
and Isisaurus
Isisaurus
Isisaurus is a genus of dinosaur from the Late Cretaceous Period. Isisaurus was a sauropod , which lived in what is now India....
. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus
Argentinosaurus
Argentinosaurus is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered...
and Paralititan
Paralititan
Paralititan was a giant titanosaurian sauropod dinosaur genus discovered in coastal deposits in the Upper Cretaceous Bahariya Formation of Egypt. The fossil represents the first tetrapod reported from the Bahariya Formation since 1935. Its 1.69 meter long humerus is longer than that of any...
— which some believe have weighed up to 100 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s (110 short ton
Short ton
The short ton is a unit of mass equal to . In the United States it is often called simply ton without distinguishing it from the metric ton or the long ton ; rather, the other two are specifically noted. There are, however, some U.S...
s). Consequently, they were named titanosaurs in honor of the mythological
Greek mythology
Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...
Titans
Titan (mythology)
In Greek mythology, the Titans were a race of powerful deities, descendants of Gaia and Uranus, that ruled during the legendary Golden Age....
, the early deities
Deity
A deity is a recognized preternatural or supernatural immortal being, who may be thought of as holy, divine, or sacred, held in high regard, and respected by believers....
of Ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
. Together with the brachiosaurids
Brachiosauridae
Brachiosauridae are a family of dinosaurs, whose members are known as brachiosaurids. They were herbivorous quadrupeds with longer forelegs than hind legs - the name derives from the Greek for arm lizard - and long necks...
and relatives, they make up the larger clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
Titanosauriformes.
Description
Titanosaurs had small heads, even when compared with other sauropods. The head was also wide, similar to the heads of CamarasaurusCamarasaurus
Camarasaurus meaning 'chambered lizard', referring to the hollow chambers in its vertebrae was a genus of quadrupedal, herbivorous dinosaurs. It was the most common of the giant sauropods to be found in North America...
and Brachiosaurus
Brachiosaurus
Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,...
but more elongated. Their nostrils were large ('macronaria
Macronaria
Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic to Late Cretaceous Periods of what are now North America, South America, Europe, Asia and Africa. The name means 'large nostrils' , in reference to the large nasal openings high on the head that probably supported fleshy...
n') and they all had crests formed by these nasal bones. Their teeth were either somewhat spatulate (spoon-like) or like pegs or pencils, but were always very small.
Their necks were relatively short, for sauropods, and their tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
s were whip-like, but not as long as in the diplodocid
Diplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
s. While the pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
(hip area) was slimmer than some sauropods, the pectoral (chest area) was much wider, giving them a uniquely 'wide-gauged' stance. As a result, the fossilised trackways
Ichnite
An ichnite is a fossilised footprint. This is a type of trace fossil. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour of the animals that made them...
of titanosaurs are distinctly broader than other sauropods. Their forelimbs were also stocky but their rear limbs were longer. Their vertebrae (back bones) were solid (not hollowed-out), which may be a throwback to more primitive saurischia
Saurischia
Saurischia meaning 'lizard' and ischion meaning 'hip joint') is one of the two orders, or basic divisions, of dinosaurs. In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure...
ns. Their spinal column was more flexible, so they were probably more agile than their cousins and better at rearing up.
From skin impressions found with the fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s, it has been determined that the skin of many titanosaur species was armored
Armour (zoology)
Armour in animals is external or superficial protection against attack by predators, formed as part of the body , usually through the hardening of body tissues, outgrowths or secretions. It has therefore mostly developed in 'prey' species...
with a small mosaic of small, bead-like scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
around a larger scale. One species, Saltasaurus
Saltasaurus
Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...
, has even been discovered with bony plates, like the Ankylosaurs.
While they were all huge, many were fairly average in size compared with the other giant dinosaurs. There were even some island-dwelling dwarf species such as Magyarosaurus
Magyarosaurus
Magyarosaurus is a genus of dwarf sauropod dinosaur from late Cretaceous Period in what is now Romania. It is one of the smallest-known adult sauropods, measuring only six meters in length. The type species is Magyarosaurus dacus...
, probably the result of allopatric speciation
Allopatric speciation
Allopatric speciation or geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration...
and insular dwarfism
Insular dwarfism
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of the reduction in size of large animals – typically mammals – when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf...
.
Derived titanosaurs had biconvex vertebrae. The primitive condition is either amphiplaty or amphicoely. Venenosaurus
Venenosaurus
Venenosaurus named after the Poison Strip Member of the Cedar Mountain Formation in Utah, where the fossils were discovered by a Denver Museum of Natural History volunteer Tony DiCroce in 1998. Venenosaurus dicrocei was first described as a new species in 2001 by Virginia Tidwell, Kenneth...
may have had a condition intermediate between the two.
Range
The titanosaurs were the last great group of sauropods before the Cretaceous-Tertiary extinction eventCretaceous-Tertiary extinction event
The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...
, about 90–65 million years ago and were the dominant herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s of their time. The fossil evidence suggests they replaced the other sauropods, like the diplodocid
Diplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
s and the brachiosaurids, which died out between the late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
and the mid-Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Periods.
Titanosaurs were widespread. Fossils have been found on all continents except Antarctica. Four well preserved skeletons of a titanosaur species were found in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, a discovery first reported on May 2, 2006. They are especially numerous in the southern continents (then part of the supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...
of Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
). Australia had titanosaurs around 96 million years ago: fossils have been discovered in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
of a creature around 25 meters long (82 feet). Remains have also been discovered in New Zealand.
Diet
Fossilized dungCoprolite
A coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
associated with late Cretaceous titanosaurids has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledon
Monocotyledon
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...
s, including palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
s and grasses (Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
), including ancestors of rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
and bamboo
Bamboo
Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....
, which has given rise to speculation that herbivorous dinosaurs and grasses co-evolved
Co-evolution
In biology, coevolution is "the change of a biological object triggered by the change of a related object." Coevolution can occur at many biological levels: it can be as microscopic as correlated mutations between amino acids in a protein, or as macroscopic as covarying traits between different...
.
Nesting
A large titanosaurid nestNest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...
ing ground was discovered in Auca Mahuevo, in Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
and another colony has reportedly been discovered in Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. Several hundred female saltasaurs
Saltasaurus
Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...
dug holes with their back feet, laid eggs in clutches averaging around 25 eggs each, and buried the nests under dirt and vegetation. The small egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s, about 11–12 cm (4–5 in) in diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
, contained fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ised embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s, complete with skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
impressions. The impressions showed that titanosaurs were covered in a mosaic armour of small bead-like scales. The huge number of individuals gives evidence of herd
Herd
Herd refers to a social grouping of certain animals of the same species, either wild or domestic, and also to the form of collective animal behavior associated with this or as a verb, to herd, to its control by another species such as humans or dogs.The term herd is generally applied to mammals,...
behavior, which, along with their armour, could have helped provide protection against large contemporary predators such as Abelisaurus
Abelisaurus
Abelisaurus is a genus of abelisaurid theropod dinosaur from the Late Cretaceous Period of what is now South America. It was a bipedal carnivore that probably reached 7 to 9 meters in length, although it is known from only one partial skull.The generic name recognizes Roberto Abel as the...
.
Systematics
The fossil record of titanosaurs, as plainsPlains
Plains is the plural of plain, a geographical feature. It is a big flat area of a land. Plains or The Plains may also refer to:-Locations:Canada*Three Mile Plains, Nova Scotia*Five Mile Plains, Nova ScotiaUnited States*Great Plains...
-dwelling herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s, has been disappointingly fragmentary for such a widespread and successful group (they represent roughly a third of the total sauropod diversity known to date). Only recently have skulls or relatively complete skeletons (see Rapetosaurus
Rapetosaurus
Rapetosaurus is a genus of sauropod dinosaur that lived in Madagascar from 70 to 65 million years ago, at the end of the Cretaceous Period. Only one species Rapetosaurus is a genus of sauropod dinosaur that lived in Madagascar from 70 to 65 million years ago, at the end of the Cretaceous Period....
) of any of the roughly 50 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of titanosaur been discovered. Many species are poorly known. Much material may be reclassified and some genera renamed as understanding of the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
grows.
The family Titanosauridae was named after and anchored on the poorly known genus Titanosaurus
Titanosaurus
Titanosaurus is a genus of sauropod dinosaur, first described by Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India...
, which was coined by Richard Lydekker
Richard Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
in 1877, on the basis of a partial femur and two incomplete caudal vertebrae. Fourteen species have since been referred to Titanosaurus, which distribute the genus across Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and Laos
Laos
Laos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...
and throughout 60 million years of the Cretaceous Period. Despite its centrality to titanosaur systematics and biogeography, a re-evaluation of all Titanosaurus species recognises only five as diagnostic. The type species T. indicus is invalid, because it is based on 'obsolescent' characters - once diagnostic features that have gained a broader taxonomic distribution over time. Consequently, use of the genus Titanosaurus has largely been abandoned. The most well known Titanosaurus specimens have since been re-assigned to other genera, including Isisaurus
Isisaurus
Isisaurus is a genus of dinosaur from the Late Cretaceous Period. Isisaurus was a sauropod , which lived in what is now India....
.
Some paleontologists (such as Sereno
Paul Sereno
Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...
, 2005 ) have contended that Titanosaurus is too poorly known to use as a basis for classification, family names for which it is the type genus (e.g. Titanosaurinae, Titanosauridae, Titanosauroidea) should not have other genera referred to them. Weishampel et al., in the second edition of The Dinosauria, also did not use the family Titanosauridae, and instead used several smaller titanosaur families such as Saltosauridae and Nemegtosauridae.
Taxonomy
Family-level taxonomy follows Holtz (2011).- Clade Titanosauria
- Superfamily Titanosauroidea
- ChubutisaurusChubutisaurusChubutisaurus is a genus of dinosaur from the Early Cretaceous Period. It lived in South America. It is classified as a sauropod, specifically one of the titanosaurs. The type species, C. insignis, was described by del Corro in 1975. Its fossils were found in the Cerro Barcino Formation, Albian...
(Argentina) - LigabuesaurusLigabuesaurusLigabuesaurus is a genus of dinosaur from the Early Cretaceous . It was a basal titanosaurid sauropod which lived in what is now Argentina. The type species, Ligabuesaurus leanzai, was described by Jose Bonaparte, Gonzalez Riga, and Sebastián Apesteguía in 2006, based on a partial skeleton...
(Argentina) - ?MongolosaurusMongolosaurusMongolosaurus is a genus of sauropod dinosaur which lived during the Early Cretaceous of China.In 1928 a team from the American Museum of Natural History, headed by Roy Chapman Andrews, at On Gong Gol near Hukongwulong in Inner Mongolia, in Quarry 714 discovered a sauropod tooth. In 1933 Charles W...
- PhuwiangosaurusPhuwiangosaurusPhuwiangosaurus is the name given to a genus of dinosaur from the Early Cretaceous. It was a titanosaur which lived in Thailand. The type species, P. sirindhornae, was described by Martin, Buffetaut, and Suteethorn in 1994, it was named to honour Princess Maha Chakri Sirindhorn of Thailand on her...
(ThailandThailandThailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
) - RuyangosaurusRuyangosaurusRuyangosaurus is a genus of sauropod dinosaur recovered from the Late Cretaceous Mangchuan Formation of China. The type species is R. giganteus, described in 2009 by a group of scientists from the Chinese Academy of Sciences and the Henan Geological Museum.Along with Huanghetitan and Daxiatitan,...
(ChinaChinaChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
) - TangvayosaurusTangvayosaurusTangvayosaurus is a genus of sauropod dinosaur from the Aptian-Albian age Lower Cretaceous Grès Supérior Formation of Savannakhet, Laos...
(LaosLaosLaos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...
) - UberabatitanUberabatitanUberabatitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Brazil. It is known from bones including neck, back, and tail vertebrae, pelvic bones, and limb bones...
- Family Andesauridae
- AndesaurusAndesaurusAndesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, it would have had a small head on the end of a long neck and an equally long tail...
(ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
)
- Andesaurus
- Family AeolosauridaeAeolosauridaeAeolosauridae is an extinct family of titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Brazil. Thomas Holtz assigned Adamantisaurus, Aeolosaurus, Gondwanatitan, Muyelensaurus, Panamericansaurus, Pitekunsaurus and Rinconsaurus to Aeolosauridae. Rodrigo M. Santucci and...
- Family ArgyrosauridaeArgyrosauridaeArgyrosauridae is a family of large titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Egypt....
- Clade LognkosauriaLognkosauriaLognkosauria is a group of giant long-necked sauropod dinosaurs within the clade Titanosauria, and includes some of the largest and heaviest dinosaurs to ever walk the earth.-Defining characteristics:...
- Clade Lithostrotia
- NarambuenatitanNarambuenatitanNarambuenatitan is a genus of lithostrotian titanosaur sauropod from late Cretaceous deposits of northern Patagonia of Argentina. Narambuenatitan is known from the holotype MAU-Pv-N-425, an incomplete skeleton. It was collected in 2005 and 2006 from the Anacleto Formation in northern Patagonia....
- Family AntarctosauridaeAntarctosauridaeAntarctosauridae is a family of titanosaurian dinosaurs known from the late Cretaceous period. They were widespread, and their fossils have been found in North America, South America, India, Mongolia, China and Australia....
- Family NemegtosauridaeNemegtosauridaeNemegtosauridae is a family of probably titanosaurian sauropod dinosaurs based originally on two late Cretaceous Mongolian species known only from their diplodocid-like skulls: Nemegtosaurus and Quaesitosaurus. Authorities disagree as to the relationship of these two genera with other sauropods,...
- Family SaltasauridaeSaltasauridaeSaltasauridae is a family of titanosaurian dinosaurs known from the late Cretaceous period of South America, Spain, Madagascar and Mongolia....
- Narambuenatitan
- Uncertain Placement (incertae sedis)
- AmargatitanisAmargatitanisAmargatitanis is a genus of titanosaur sauropod dinosaur from the Barremian-age La Amarga Formation of Neuquén, Argentina...
(Argentina) - AustrosaurusAustrosaurusAustrosaurus was a sauropod dinosaur from the Allaru Mudstone, from the early Cretaceous of Central-Western Queensland in Australia.-Discovery and species:...
(AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
) - BaurutitanBaurutitanBaurutitan was a genus of sauropod dinosaur that appeared in the Late Cretaceous Period. This plant eater grew up to 79 feet long. It was a titanosaur which lived in what is now present-day Brazil....
(Brazil) - BruhathkayosaurusBruhathkayosaurusBruhathkayosaurus might have been the largest dinosaur that ever lived. The accuracy of this claim, however, has been mired in controversy and debate...
(India) - GobititanGobititanGobititan is a genus of dinosaur from the mid-Cretaceous. The genus is based on one partial skeleton, composed of spinal vertebrae and a partial limb. Based on the partial skeleton, it is believed to have been a basal titanosaur, a type of sauropod. The type species, Gobititan shenzhouensis, was...
(China) - HypselosaurusHypselosaurusHypselosaurus was a long titanosaurid sauropod that lived in Europe during the Late Cretaceous Period .Hypselosaurus was scientifically described by geologist Pierre Émile Philippe Matheron in 1846 and formally named in...
(Europe) - IuticosaurusIuticosaurusIuticosaurus is the name given to a genus of dinosaur from the Early Cretaceous of the Isle of Wight. Iuticosaurus was a sauropod, specifically a titanosaur....
(UK) - JainosaurusJainosaurusJainosaurus is a large titanosaurian dinosaur of India and wider Asia, which lived in the Maastrichtian ....
(India) - JiangshanosaurusJiangshanosaurusJiangshanosaurus was a titanosaurian sauropod that lived approximately 105 million years ago, during the Albian stage of the Early Cretaceous. Its remains were discovered in Lixian Village, Jiangshan county, in the eastern Chinese province of Zhejiang. The type and only known species,...
(China) - KarongasaurusKarongasaurusKarongasaurus is the name given to a genus of dinosaur from the Early Cretaceous. It was a titanosaurid sauropod. Its fossils, consisting solely of part of a lower mandible and a few teeth, were found in Malawi...
(Malawi) - LaplatasaurusLaplatasaurusLaplatasaurus is a genus of titanosaurid sauropod dinosaur that lived during the Late Cretaceous in South America....
(Argentina, Uruguay) - MaxakalisaurusMaxakalisaurusMaxakalisaurus is a genus of aeolosaurid dinosaur, found in Brazil, 45 kilometers from the city of Prata, in the state of Minas Gerais in 1998...
(Brazil) - PaludititanPaludititanPaludititan is a genus of titanosaurian dinosaur which existed in what is now Haţeg Basin, Romania during the late Cretaceous period. The type species is Paludititan nalatzensis, after its finding place Nǎlaţ-Vad. The type species was determined and described by Zoltán Csiki, Vlad Codrea, Cǎtǎlin...
(Romania) - PuertasaurusPuertasaurusPuertasaurus is a genus of titanosaurid sauropod that appeared during the Late Cretaceous. It lived in what is now Patagonia. The type species, Puertasaurus reuili, is named in honor of Pablo Puerta and Santiago Reuil, the co-discoverers in January 2001 of the specimen...
(Argentina) - TitanosaurusTitanosaurusTitanosaurus is a genus of sauropod dinosaur, first described by Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India...
(India) - VenenosaurusVenenosaurusVenenosaurus named after the Poison Strip Member of the Cedar Mountain Formation in Utah, where the fossils were discovered by a Denver Museum of Natural History volunteer Tony DiCroce in 1998. Venenosaurus dicrocei was first described as a new species in 2001 by Virginia Tidwell, Kenneth...
(USA) - WintonotitanWintonotitanWintonotitan is a genus of titanosauriform dinosaur from late Albian -age rocks of Australia. It is known from partial postcranial remains.-Description and history:...
, nicknamed "Clancy" (Australia)
- Amargatitanis
- Chubutisaurus
- Superfamily Titanosauroidea
Phylogeny
In the second edition of The Dinosauria, the clade Titanosauria was defined as all sauropods closer to Saltasaurus than to Brachiosaurus. A few scientists, such as Paul Sereno, use definitions which exclude Euhelopus as well as Brachiosaurus.Relationships within the Titanosauria have historically been extremely variable from study to study, complicated by the fact that clade and rank names have been applied inconsistently by various scientists. One possible cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
is presented here, and follows a 2007 analysis by Calvo and colleagues. The authors notably used the family Titanosauridae in a broader fashion than other recent studies, and coined the new clade name Lognkosauria.
External links
- Titanosauria on DinoData
- The Geological Society article Best ever titanosaur skeleton discovered in Madagascar.
- National Geographic article, Eggs Hold Skulls of Titanosaur Embryos.
- Channel 4 article, Titanosaur eggs in France.