Greetings!

This page is dedicated to keeping you updated with a list of all known genera of Mesozoic dinosaurs, arranged according to the groups to which they belong. This list is provided as an Adobe PDF format, which is readable by most web browser programs and printable on most computers. If you need to get a copy of Adobe Acrobat Reader, you can go here to download a copy of the software.

I also include an expanded version of the introduction to the dinosaur genus list. This includes material that was going to be in the published version of the book, but had to be cut out to save on space.

I will try to update this list when the opportunity arises, hopefully once a season. The first update was 31 July 2008. That update included the addition of 108 new genera and 55 new classification categories. If you are interested, here are the new additions:

• New genera added for 31 July 2008 are: 26 genera awaiting official names, plus Achillesaurus, Albertonykus, Alethoalaornis, Aniksosaurus, Aristosaurus, Asylosaurus, Australodocus, Balochisaurus, Berberosaurus, Brohisaurus, Cedrorestes, Cerasinops, Cerebavis, Dakotadon, Dalingheornis, Dashanpusaurus, Diceratus, Didactylornis, Dollodon, Dongbeititan, Dongyangosaurus, Dracovenator, Dromomeron, Elsornis, Enantiophoenix, Eocarcharia, Eoconfuciusornis, Eocursor, Eomamenchisaurus, Fusuisaurus, Futalognkosaurus, Gigantoraptor, Gigantspinosaurus, Glacialisaurus, Huanghetitan, Khetranisaurus, Koutalisaurus, Lamplughsaura, Liaoningornis, Lophostropheus, Loricatosaurus, Luanchuanraptor, Macrogryphosaurus, Mahakala, Mantellisaurus, Marisaurus, Martinavis, Maxakalisaurus, Microceratus, Muyelensaurus, Nanningosaurus, Nanosaurus, Nopcsaspondylus, Orkoraptor, Ornithotarsus, Oryctodromeus, Othnielosaurus, Pakisaurus, Paluxysaurus, Pantydraco, Paraprotopteryx, Pengornis, Pradhania, Qingxiusaurus, Sacisaurus, Sahaliyania, Shanag, Sinocalliopteryx, Sulaimanisaurus, Suzhousaurus, Theiophytalia, Turiasaurus, Uberabatitan, Urbacodon, Velafrons, Wulagasaurus, Xenoposeidon, Xuanhuaceratops, Yamaceratops, Zhejiangosaurus, Zhongornis, Zhongyuansaurus, and Zhuchengosaurus

• New genera added for 13 January 2011 are: 6 genera awaiting an official name, plus Aardonyx, Abydosaurus, Adeopapposaurus, Aerosteon, Ajkaceratops, Alamitornis, Albalophosaurus, Anatosaurus, Anchiornis, Angulomastacator, Arkharavia, Arenysaurus, Asilisaurus, Astinganosaurus, Australovenator, Austrocheirus, Austroraptor, Balaur, Banji, Baotianmansaurus, Barilium, Barrosasaurus, Bauxitornis, Beishanlong, Bishtahieversor, Blasisaurus, Bolong, Ceratonykus, Chromogisaurus, Chuxiongosaurus, Coahuilaceratops, Concavenator, Cruxicheiros, Daxiatitan, Demandasaurus, Diabloceratops, Diamantinasaurus, Duriatitan, Duriavenator, Dyoplosauurus, Dysalotosaurus, Elbretornis, Elrhazosaurus, Eodromaeus, Epidexipteryx, Flexomornis, Fruitadens, Fukuititan, Geminiraptor, Glishades, Haplocheirus, Helioceratops, Hesperonychus, Hippodraco, Hollanda, Huoshanornis, Hypselospinus, Ignavusaurus, Iguanacolossus, Intiornis, Jeyawati, Jianchangornis, Jintasaurus, Kayentavenator, Kemkemia, Kileskus, Kinnareemimus, Kol, Koreaceratops, Koreanosaurus, Kosmoceratops, Kukufeldia, Leshanosaurus, Lesnesovia, Limusaurus, Linheraptor, Liubangosaurus, Longicrusavis, Luoyanggia, Malarguesaurus, Machairasaurus, Medusaceratops, Minotaurasaurus, Miragaia, Naramguenatitan, Ojoceratops, Owenodon, Paludititan, Panamericansaurus, Panphagia, Peloroplites, Pitekunsaurus, Pneumatoraptor, Proplanicoxa, Qiaowanglong, Qiupalong, Rahiolisaurus, Rapaxavis, Raptorex, Rubeosaurus, Ruyangosaurus, Sanjaunsaurus, Sarahsaurus, Seitaad, Sellacoxa, Shanweiniao, Shaochilong, Shenshiornis, Shenqiornis, Shidaisaurus, Similicaudipteryx, Sinoceratops, Sinotyrannus, Skorpiovenator, Spinophorosaurus, Tastavinsaurus, Tatankacephalus, Tatankaceratops, Tawa, Tethyshadros, Texacephale, Tianyulong, Tianyuraptor, Titanoceratops, Tongasaurus, Traukutitan, Utahceratops, Vagaceratops, Wintonotitan, Xianshanosaurus, Xiongguanlong, Xixiankykus, Xixiasaurus, Zanabazar, Zhongjiangornis, Zhuchengceratops, and Zuolong ("General Tso's dinosaur").

• Genera removed for 6 January 2011: Diceratus (now in Triceratops) and Homalocephale (now in Prenocephale).

• New genera added for 10 January 2012 are: eight genera awaiting an official name, plus Acristavus, Ahshishapelta, Albinykus, Amtocephale, Angolatitan, Arcusaurus, Atacamatitan, Bohaiornis, Bonapartenykus, Brontomerus, Cathayornis, Daemonosaurus, Delapparentia, Diodorus, Drusilasaura, Epichirostenotes, Gracilornis, Gryphognathus, Haya, Huaixasaurus, Leonerasaurus, Leyesaurus, Linhenykus, Linhevenator, Manidens, Mystiornis, Nambalia, Jaklapallisaurus, Ojoraptorsaurus, Osmakasaurus, Oxalaia, Pampadromaeus, Pamparaptor, Parahonshanornis, Petrobrasaurus, Propanoplosaurus, Qiliania, Ratchasimasaurus, Spinops, Talos, Tapuiasaurus, Teratophoneus, Unescoceratops, Uteodon, Veterupristisaurus, Xiaotingia, Xuwulong, Yueosaurus, Zuchengtyrannus

• Genera removed for 31 December 2011: Bugensaura (now in Thescelosaurus (Chapter 30); Dollodon and Proplanicoxa (now in Mantellisaurus) and Kukufeldia and Sellicoxa (now in Barilium) (Chapter 31); Anatotitan (now in "Anatosaurus") (Chapter 32)

• New genera added for 19 January 2015 are: Acheroraptor, Ajancingenia, Alnashetri, Anzu, Aorun, Arcovenator, Aurornis, Bicentenaria, Camarillasaurus, Changyuraptor, Datanglong, Eoabelisaurus, Eosinopteryx, Fosterovenator, Gobivenator, Gryphoceratops (replaces "Gryphognathus"), Hexing, Ichthyovenator, Ignotosaurus, Jianchangosaurus, Jiangxiasaurus, Juratyrant, Leptorhynchos, Lutungutali, Lythronax, Martharaptor, Nankangia, Nanuqsaurus, Ningyuansaurus, Nyasasaurus, Ostafrikasaurus, Panguraptor, Pectinodon, Philovenator, Qianzhousaurus, Siats, Sauroniops, Tachiraptor, Wulatelong, Yulong, Yurgovuchia, Yutyrannus

• Genera removed for 19 January 2015: Crosbysaurus, Galtonia, Gryphognathus (replaced with Gryphoceratops), Krzyzanowskisaurus, Lucianosaurus, Pekinosaurus, Protecovasaurus, Razanandrongobe, Sigilmassasaurus (now in Spinosaurus), Tecovasaurus, Trialestes, Wellnhoferia (now in Archaeopteryx)

• New classification categories added for 31 July 2008 are (in order of appearance in the book and table): Lagerpetonids, Silesaurs (Chapter 11); Dilophosaurids and relatives (Chapter 13); "Megalosaurs", Megaraptors (Chapter 14); Primitive Oviraptorids, Elmisaurines, "Ingeniines" (Chapter 19); Sapeornithids, Confuciusornithids, Primitive Enantiornithines, Primitive Euenantiornithines, Avisaurids, Gobipterygids, Longipterygids, Primitive Euornithines, Yanornithiforms, Advanced Euornithines (Chapter 21); Primitive Sauropodomorphs, Plateosaurids, Riojasaurids, Massospondylids, Near-Sauropods (Chapter 22); Primitive Sauropods, Vulcanodontids, Primitive Eusauropods, Primitive Cetiosaurids, Mamenchisaurines, Turiasaurs, Primitive Neosauropods (Chapter 23); Apatosaurines, Diplodocines (Chapter 24); Argyrosaurids, Aeolosaurids, Lognkosaurs, Antarctosaurids, Nemegtosaurids (Chapter 25); Primitive Stegosaurs, Stegosaurids (Chapter 28); Primitive Neornithischians, Zephyrosaurs(Chapter 30); Dryosaurids, Camptosaurids, Primitive Styracosternans (Chapter 31); Primitive Lambeosaurines, Parasaurolophinins, Corythosaurinins, Primitive Hadrosaurines, Gryposaurinins, Saurolophinins, Edmontosaurinins (Chapter 32); Primitive Pachycephalosaurs, Pachycephalosaurids (Chapter 33); Chaoyangsaurids and Other Primitive Ceratopsians, Psittacosaurids (Chapter 34)

• New classification categories added for 6 January 2011 are (in order of appearance in the book and table): Silesaurids (replaces silesaurs) (Chapter 11); Herrerasaurs (replaces "Herrerasaurids"), Primitive Theropods (Chapter 12); Elaphrosaurs, Ceratosaurids (Chapter 13); Primitive Megalosauroids, Megalosaurids (Chapter 14); Primitive Carcharodontosaurs, Primitive Neovenatorids, Megaraptorans (Chapter 15); Coelurids (Chapter 16); Proceratosaurids, Near-Tyrannosaurids (replaces "Primitive Tyrannosaurids") (Chapter 17); Primitive Alvarezsauroids, Parvicursorines (replaces "Mononykines") (Chapter 18); Saurornitholestines (Chapter 20); Archaeopterygids, Scansoriopterygids, Omnivoropterygids (replaces "Sapeornithids") (Chapter 21); Guaibasaurids (Chapter 22); Huayangaosauridae, Primitive Stegosaurids, Dacentrurines, Stegosaurines (Chapter 28); Thescelosaurids (Chapter 30); Primitive Hadrosaurians (replaces "Primitive Hadrosauroids"), Maiasaurinins (Chapter 32); Bagaceratopsids (Chapter 34); Primitive Ceratopsids, Chasmosaurines (replaces "Ceratopsines") (Chapter 35)

• New classification categories added for 12 December 2012 are (in order of appearance in the book and table): Elmisaurids (replaces "Elmisaurines"), Oviraptorids (replaces "Oviraptorines") (Chapter 19); Primitive Ankylosaurids and Ankylosaurines (former just "Ankylosaurids") (Chapter 29); Changchungsaurs (previously included in "Primitive Ornithopods") (Chapter 30); Primitive Saurolophines and Brachylophosaurinins (the latter replaces "Maiasaurinins") (Chapter 32)

• New classification categories added for 19 January 2015 are (in order of appearance in the book and table): Primitive Neotheropods, Primitive Abelisaurids, Majungasaurines, Primitive Brachyrostrans, Carnotaurinins (the last four replace "Abelisaurids") (Chapter 13); Piatnitzkysaurids (replaces part of "Primitive Megalosauroids"), Primitive Megalosaurids, Afrovenatorines, Megalosaurines (the last three replace "Megalosaurids"), Primitive Spinosaurids, Baryonychines, Spinosaurines (the last three replace "Spinosaurids") (Chapter 14); Primitive Metriacanthosaurids, Metriacanthosaurines (the last two replace "Sinraptorids"), Primitive Carchaodontosaurids, Gigantosaurinins (the last two replace "Carcharodontosaurids"), Primitive Megaraptorans, Megaraptorids (the last two replace "Megaraptors") (Chapter 15); Deinocheirids (Chapter 18); Caudipterids (Chapter 19); Primitive Eumaniraptorans, Anchiornithines, Jinfengopterygines, Advanced Troodontids (the last three replace "Troodontids") (Chapter 20)

• Classification categories removed for 2 January 2015 are (in order of original appearance in the book and table): Dilophosaurids (now found to be a collection of primitive theropods from different parts of the family tree) (Chapter 13); Primitive Caenagnathoids (Chapter 19); Archaeopterygids (Chapter 21);

These new additions are highlighted on the list with an "*" if it is a new genus, with a "^" it is a new name for a genus without a genus name in the original list; and a "**" if it is a new classification category.

Expanded Introductory Information:

In the following list, I've arranged all the known genera of Mesozoic dinosaurs according to the groups to which they belong. A genus, as you may recall, (if not, see chapter 7) is the one-word name that we typically use when talking about dinosaurs. Tyrannosaurus, Triceratops, and Ankylosaurus are all examples of a genus. Each genus is a group of one or more species. Most dinosaur genera are known from only a single species, but a few (such as Psittacosaurus, Apatosaurus, and Edmontosaurus) are known from several different species. Each group of genera is shown in the same order as their respective chapters in this book.

Some things to note: I have not included genera of Cenozoic dinosaurs--that is, modern birds and the other birds that lived after 66 million years ago--in this list. There are simply too many of them! And since dinosaurs are being discovered and named at a rate of about two new genera per month, this list will lack a few recent names. (In an illustrated book such as this, there is a minimum time of approximately three months between when the text is released to print and when finished books are available in bookstores and libraries.) Also, in some cases, the placement of a particular genus in a group is very uncertain. This can happen when a genus is known only from a very incomplete fossil, or when it has a confusing mixture of features. I've excluded dinosaur genus names that are based on material so fragmentary that it is very difficult to say what groups they belong to.

Some dinosaurs are currently without proper names. For example, there is a dinosaur that was once called "Ingenia." Unfortunately, there is also a nematode worm called Ingenia, and it was named first! So by the proper rules of naming, the worm keeps the name and the dinosaur needs a new one. In 2013, the "Ingenia" dinosaur was given the new genus name Ajancingenia.

Also, there are dinosaur fossils that were once considered new species in previously named genera, but which turn out not to really belong to those, or to any other already named, genera. These will eventually get their own genus name when newer studies are completed. Because some of these species are interesting (maybe they are the only member of their group from a particular time or region; maybe they have some peculiar feature), I've put them in the appendix, too. These unnamed (or at least un-genus-named) dinosaurs are being studied, and as those names are finally given I'll make sure they get included in future versions of this list.

Also, paleontologists and biologists who work on modern animals, I might add, sometimes disagree on whether two particular species belong to the same genus or to two different genera (see chapter 7). I've tried to indicate some of these differences of opinion in this list, which is based on my interpretations of the best classifications.

For each genus, I list the name and what it means.

I also give the dinosaurs age: both the geologic epoch it comes from and approximately when (in millions of years ago) it lived. Unfortunately, our understanding of how old a dinosaur was is only as good as our understanding of the age of the rocks it was found in. The ages of some rocks are pretty well known: for these dinosaurs, we have very narrow time ranges. For others, though, the geologic ages are much less certain, so I list much longer possible ages for the oldest and youngest that dinosaur might be. Future studies should narrow those ranges down. In the 2015 updates the range of some of these ages have become very narrow. This is because some long on-going projects to precisely plot where each fossil specimen was found in certain geologic units--and when in time those particular layers were deposited--have finally been published. This much greater precision is giving us a better idea of which dinosaurs lived at the same time as each other. It also suggests that MOST dinosaur genera probably lasted for only a million years or so; if we knew the geology better, and had more samples to examine, we could probably narrow down the age ranges of most of the dinosaurs on this list to just a million years.

I give the length for these dinosaurs, based on the largest specimens. (Of course, for dinosaurs that are only known from babies, those "largest specimens" are a LOT smaller than the adult would be!) Since most dinosaurs are known from incomplete fossils, these measurements are often just guesses. Particularly wild guesses are marked with a question mark. (After all, since many dinosaurs are mostly tail and neck, and since tails and necks vary widely in some groups, it is pretty tough to make even a reasonable guess.) And since some dinosaurs are known from just a few tail bones or the like, there is no way to be accurate for these lengths. In these cases, I have just put a question mark. Keep these facts in mind. Also, keep in mind that the largest individuals may not be a typical individual. After all, consider really tall basketball players or really massive (American) football linesmen: they show that there are people who are much larger than the average individual, but still part of the normal variation of our species. The same was true of dinosaur species: not all Tyrannosaurus rex adult males would have been exactly the same size!

Keep in mind also that many dinosaurs are known from only a few individuals, so are unlikely to be large individuals. And even more importantly, they might not even be adults! In fact, even in some of the best known dinosaurs (Allosaurus and Apatosaurus are two good examples) we do not have definite adult individuals known, so the actual largest size of these genera is not yet known.

Weights are even tougher to determine. A baby dinosaur of just a few pounds could grow up to be a dinosaur weighing dozens of tons. So where I can, I give the weight of the biggest individuals. Instead of given exact numbers (which sound pretty accurate, but are really just guesses), I list a modern animal of around the same size as that dinosaur. Here is the list of modern animals, the weight they represent, and other modern animals in that size range: