Hello and welcome to my first blog on the wonders of the world of paleontology. The University of California Museum of Paleontology, states paleontology can be described as a study of how fossils can educate us about past ecologies, evolution and where humans stand in the world. It is certainly a subject which is capable of capturing the imagination of those young and old. I remember as a young child entering London's Natural History Museum for the first time and being instantly awestruck by the famous Diplodocus cast "Dippy". It as many people would testify, is an incredible experience and cannot fail to make the mind wonder in an attempt to imagine a world where magnificent beasts such as these would be common place. It was dinosaurs which triggered my interest in paleontology and it is this subject which seems a good place to start my first few publications in this blog. I hope you enjoy reading them and I always appreciate feedback whether it be positive or constructive criticism.
Dinosaur orders.
Dinosaurs roamed the Mesozoic era which started 250 million years ago and ended 65 million years ago. The fossil records show that throughout this time they would have appeared in an incredible variety of shapes and sizes. Their success is evident today in the form of their modern day relatives birds. Dinosaurs are separated into two orders, ornithischian and saurischian dinosaurs and it is those of the saurischia order who are the ancestors of birds.
Saurischian dinosaurs.
Saurischian dinosaurs the earliest on historical record, are also known as lizard hipped dinosaurs. Their pubis bone pointed downwards and forwards in contrast to ornithischian dinosaurs which had a pubis bone pointed downwards and backwards. Saurischian dinosaurs are divided into two groups, sauropods and theropods.
Sauropodomorphs.
Sauropods grew to colossal sizes which lived from the late Triassic to the end of the dinosaur era. They were incredibly successfully and populated across all continents and a variety of habitats including deserts, forests and polar regions. Sauropods had long necks, small heads, small brains, long tails and four to five toes. Despite being at least semi quadruple, all sauropods would have been able to rear up on their hind legs. Sauropods were predominantly herbivorous. They would have used their long necks, specially designed teeth and their ability to stand on their back legs to reach and strip vegetation out of reach for other herbivores. Gizzard stones have been found with sauropod remains and it is widely thought these would have been used to grind ingested food items.
http://www.nhm.ac.uk/resources-rx/images/1007/dippy-banner_125459_2.jpg
Theropods.
Although predominately made up of carnivorous species, this group also includes and omnivores and out and out herbivores. All theropods would have walked on two legs, and most would have had three claws. Their head shape and size of their heads were variable. Skull bones were often loosely attached to each other. Theropod feeding behavior ranged from acts of predation, scavenging and herbivorous feeding. Consequently, teeth size and shape showed large variations.
http://www.amnh.org/var/ezflow_site/storage/images/media/amnh/images/permanent-exhibitions/fossil-halls/hall-of-saurischian-dinosaurs2/tyrannosaurus-rex/150313-1-eng-US/tyrannosaurus-rex_dynamic_lead_slide.jpg
Ornithischian dinosaurs.
Ornithischian dinosaur species were mainly herbivorous and had a special predentary bone to help them with this lifestyle. This formed on the lower jaw and helped to form a beak, which was used for slicing, while the teeth grinded and chewed food at the back of the jaw. As previously mentioned, in contrast to saurischian dinosaurs, ornithischian dinosaurs or bird hipped dinosaurs pubis bone faced backwards. This would have allowed extra room for an enlarged digestive track. Ornithichians were highly adaptable and lived in a variety of habitats.
Lineages of Ornithischian dinosaurs.
http://www.ucmp.berkeley.edu/diapsids/ornithischia/zunicer_skull.jpg
Hadrosaurs - Hadrosaurs were Iguanodontoids which possessed a characteristic duck bill and a specialized dental battery. This comprised of a minimum three teeth in each position forming a grinding pavement, made up of hundreds of teeth. These were used to crush vegetation. These dinosaurs were present in the Americas, Eurasia and Antarctica during the late Cretaceous. Hadrosaurs laid up to twelve eggs in a pit nest with soil deposited on them.
http://museumvictoria.com.au/pages/8750/MM-hadrosaur-illustration-BIG.jpg
Ankylosauria - Ankylosaurids lived in North America and Asia during the Cretaceous period. Their body armor was truly amazing, with osteoderms all over their body, their heads were armored with triangular hornlets, and in some cases even their eyelids were reinforced. Some species also used modified tail clubs. As well as being used for protection, it has been suggested that tail clubs may have been used for display and for fighting among themselves. The front of the upper jaw possessed no teeth and the teeth that were present in other parts of the jaw were small and leaf shaped.
Sauropodomorphs.
Sauropods grew to colossal sizes which lived from the late Triassic to the end of the dinosaur era. They were incredibly successfully and populated across all continents and a variety of habitats including deserts, forests and polar regions. Sauropods had long necks, small heads, small brains, long tails and four to five toes. Despite being at least semi quadruple, all sauropods would have been able to rear up on their hind legs. Sauropods were predominantly herbivorous. They would have used their long necks, specially designed teeth and their ability to stand on their back legs to reach and strip vegetation out of reach for other herbivores. Gizzard stones have been found with sauropod remains and it is widely thought these would have been used to grind ingested food items.
http://www.nhm.ac.uk/resources-rx/images/1007/dippy-banner_125459_2.jpg
Theropods.
Although predominately made up of carnivorous species, this group also includes and omnivores and out and out herbivores. All theropods would have walked on two legs, and most would have had three claws. Their head shape and size of their heads were variable. Skull bones were often loosely attached to each other. Theropod feeding behavior ranged from acts of predation, scavenging and herbivorous feeding. Consequently, teeth size and shape showed large variations.
http://www.amnh.org/var/ezflow_site/storage/images/media/amnh/images/permanent-exhibitions/fossil-halls/hall-of-saurischian-dinosaurs2/tyrannosaurus-rex/150313-1-eng-US/tyrannosaurus-rex_dynamic_lead_slide.jpg
Ornithischian dinosaurs.
Ornithischian dinosaur species were mainly herbivorous and had a special predentary bone to help them with this lifestyle. This formed on the lower jaw and helped to form a beak, which was used for slicing, while the teeth grinded and chewed food at the back of the jaw. As previously mentioned, in contrast to saurischian dinosaurs, ornithischian dinosaurs or bird hipped dinosaurs pubis bone faced backwards. This would have allowed extra room for an enlarged digestive track. Ornithichians were highly adaptable and lived in a variety of habitats.
Lineages of Ornithischian dinosaurs.
Ceraptopsians - The earliest ceratopsians were small and bipedal, while later species would have lived life as large quadrupeds. Species such as the famous triceratops had bony protective frills and horns. Horns may also have been used as a way for species to identify each other. Ceraptopsians had narrow skulls and parrot like beaks, while their teeth would have sheered and sliced plants.
http://www.ucmp.berkeley.edu/diapsids/ornithischia/zunicer_skull.jpg
Hadrosaurs - Hadrosaurs were Iguanodontoids which possessed a characteristic duck bill and a specialized dental battery. This comprised of a minimum three teeth in each position forming a grinding pavement, made up of hundreds of teeth. These were used to crush vegetation. These dinosaurs were present in the Americas, Eurasia and Antarctica during the late Cretaceous. Hadrosaurs laid up to twelve eggs in a pit nest with soil deposited on them.
http://museumvictoria.com.au/pages/8750/MM-hadrosaur-illustration-BIG.jpg
Ankylosauria - Ankylosaurids lived in North America and Asia during the Cretaceous period. Their body armor was truly amazing, with osteoderms all over their body, their heads were armored with triangular hornlets, and in some cases even their eyelids were reinforced. Some species also used modified tail clubs. As well as being used for protection, it has been suggested that tail clubs may have been used for display and for fighting among themselves. The front of the upper jaw possessed no teeth and the teeth that were present in other parts of the jaw were small and leaf shaped.
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| Images taken by author. |
Stegosauria - Stegosaurids had a wide range throughout the late Jurassic and early Cretaceous period. Like ankylosaurs, they no teeth at the front of their upper jaw and the teeth they did have were small and leaf shaped. Their skulls were small, long and narrow. Early stegosaurs had spikes along their backs while later species would develop plates made of osteoderms.
http://blogs.smithsonianmag.com/dinosaur/files/2011/03/stegosaurus-carnegie.jpg
Pachycephalosaurids - These dinosaurs lived during the Cretaceous period and would have been found in the northern hemisphere. Pachycephalosaurids are separated into two groups, flat headed and dome headed. It is considered likely that the flat headed group may be just young or female individuals from the dome headed group. It is theorized these skulls were used for species recognition and or as a battering ram.
http://blogs.smithsonianmag.com/dinosaur/files/2011/03/stegosaurus-carnegie.jpg
Pachycephalosaurids - These dinosaurs lived during the Cretaceous period and would have been found in the northern hemisphere. Pachycephalosaurids are separated into two groups, flat headed and dome headed. It is considered likely that the flat headed group may be just young or female individuals from the dome headed group. It is theorized these skulls were used for species recognition and or as a battering ram.
http://cdn4.sci-news.com/images/enlarge/image_1247_1e-Pachycephalosaurus.jpg
Well that concludes my first publication for this blog. I really hope you have enjoyed reading it. Next week I will go into more detail about dinosaur predatory and defensive adaptions. As I said earlier any feedback is massively appreciated, and thank you for reading.
George.
Twitter- reallywildwykes.
George.
Twitter- reallywildwykes.
Information was sourced as a result of my own studies online with Coursea, Dinosaurs a Field Guide by Gregory S Paul and from this link http://www.ucmp.berkeley.edu/paleo/paleowhat.html.
