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—as of November 7, 2008

The Dinosaur Genera List became a standalone website on December 4, 2000
on America Online's Hometown domain. AOL closed the domain down
on Halloween, 2008, so the List was carried over to the www.polychora.com
domain in early November, 2008. The final visitor count before AOL Hometown was closed
down was 93661, on October 30, 2008.

Download a PDF of this web page here.

HIS ALPHABETIZED LIST comprises all dinosaur generic names based on skeletal material known to have been published anywhere, with or without formal scientific descriptions. Names printed in bold italics are scientifically valid; other names are vernacular, preoccupied, or otherwise scientifically invalid. Occasionally it is found that two different names have been given to the same genus. Such names are known as synonyms, and instances of synonymy are annotated in the List (see Synonymies in List section below). Being a synonym by no means invalidates a generic name, since the junior synonym is usually available in case a synonymy is refuted or the senior synonym is found to be preoccupied.

The names appear in this List without regard to their validity or synonymy, but each name is associated in some way, formally or informally, with real fossil material. Names of dinosaur footprint and egg genera, however, or of fictional, fictitious, or fraudulent dinosaurs, are not included. Published Japanese common names, usually ending in “-ryu,” are not included unless they have been Latinized elsewhere in print. Also not included are names that have appeared solely on the Internet, or in e-mails, in advance of publication (there are usually four or five such floating around at any particular time). Author(s) and year of publication are provided for each name, to facilitate locating original references. For more information on any genus, simply enter its name into a Google search, or subscribe to Tracy Ford’s Paleofile website.

Different authors with the same surname are distinguished by their initials or by entire first names if initials are not sufficient. Prior to August 2007, the List did this haphazardly, particularly for Oriental authors, but thanks to bibliographic research by Rob Taylor, I was able to make the entries quite consistent throughout, with only a few remaining ambiguities (we are working on them). Also, when an author has used different surnames in different references, I provide a consistent surname throughout but indicate in parentheses the surname as it appears in the description, when it is different. Chinese and Korean authors are standardly listed surname first, regardless of how their names were cited. This should facilitate using the List in computer searches by author. Because there are many, I have not indicated these changes with green text. A few typos may persist in the additions for a while until they are caught and weeded out.

For the purposes of this List, a dinosaur is defined as any archosaur more closely related to modern birds than to modern crocodylians that is not itself a true bird. I call the stem-based clade of archosaurs more closely related to modern birds than to modern crocodylians Ornithes, the clade of modern birds Aves (by tradition, the common ancestor of all extant birds together with all its descendants), and the clade of true birds Avialae (by tradition, the common ancestor of modern birds and Archaeopteryx together with all its descendants). If dinosaurs were defined here as a clade instead of as the difference between two clades, then all birds would be dinosaurs, and the Dinosaur Genera List would be obliged to include the names of thousands of fossil and extant bird genera along with the names of the genera that most of us are accustomed to calling dinosaurs: interesting, but probably not what one might be looking for as a list of dinosaur names.

So, according to this scheme, dinosaurs become “non-avialan ornithans.” But note that this definition also includes what have been termed “pre-dinosaurs,” or “dinosaur precursors,” that is, archosaurs on the stem that joins the common ancestor of crocodylians and birds to the most basal known dinosaurs. So far, no convincing (to me) dinosaur precursors have been identified in the fossil record, although many consider the lagosuchians from South America, and some others, to be such. The successively more inclusive clades Dinosauriformes Novas, 1992 and Dinosauromorpha Benton, 1985 have been created to include these forms as outgroups to Dinosauria, so those archosaurs become “non-dinosaurian dinosauriforms” and “non-dinosauriform dinosauromorphs.” To me, this is outrageous hairsplitting, particularly since the forms in these groups are few in number and most appear to me to be basal theropods rather than basal dinosaurs. Until more convincing arguments are published on why such forms should not be called dinosaurs, I'll retain them in the Dinosaur Genera List without further annotation. Perhaps later, when I perform a List overhaul, I may annotate them as “precursor dinosaurs.”

This is the Mother of All Internet Dinosaur Lists. It was first posted to the Dinosaur Mailing List (see archive) on October 23, 1995. Thereafter, it was gradually corrected and tuned to weed out misspellings and other inappropriate generic names, eventually evolving into its present form. Before October 1995, there was simply no complete list of dinosaur genera available on the Internet; all the other Internet dinosaur lists, some with much additional information, sprang up after this one became available. The initial Dinosaur Genera List tabulated 770 names, after a few non-dinosaurian genera that had crept in were removed. The entire List was published as part of The Dinosaur Folios #1 in May 1996, when it had grown to 787 names long. It was also published in 1997, when the name count stood at 806, at the back of Encyclopedia of Dinosaurs (Currie & Padian, eds.). On or about May 24, 1997, the entire List, with the name count at 805, was posted on the Dinogeorge website home page. There it remained until it became the present separate web page on December 3, 2000, with the name count at 895.

The Dinosaur Genera List is freely available to anyone who desires to publish it in book or magazine form, to link to it, or to display it at a website, provided only that George Olshevsky be informed of such publication or Internet display, and be properly credited as compiler.

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What are genera?
Genus (plural: genera) is a major category invented in the mid-1750s by the botanist Carolus Linnaeus (or Karl von Linne) for his system of classifying nature. His Systema Naturae is still, more than 250 years later, in use by naturalists and biologists worldwide. The lowest-ranking major category is the species, and the genus is the next lowest-ranking major category. Originally, Linnaeus simply grouped anatomically similar species into genera. Now, however, we understand that organisms are similar because they evolved from an earlier common ancestor most of whose features they retain. So a more modern definition of a genus would be: a group of species having a closer common ancestor than other species in the same family.

To designate each species, Linnaeus combined two names into what is known as a species binomen. The first part, or generic name, is the name of the genus to which the species belongs. The second part, known as the species epithet or trivial name, uniquely distinguishes the species within the genus. These names are Latinized, a relic of the days of Linnaeus, when Latin was the language of science. In a species binomen, the generic name is always a Latinized noun, and the species epithet acts as a Latin modifier of that noun. Some genera may include hundreds of species, others may include only one species. Most dinosaur genera, however, include just one species, because of the difficulty of distinguishing species among fossils. The generic name is the more important name, so practically all dinosaurs are popularly known by just their generic names. (The one major exception, of course, is Tyrannosaurus rex, in which Tyrannosaurus is the generic name and rex is the species epithet. Everybody knows this dinosaur by its full species binomen.) Because of their importance in dinosaur science, the Dinosaur Genera List collects in alphabetical order all the generic names ever given to non-avian dinosaurs (that is, dinosaurs that are not also birds, or “non-avialan ornithans”).

It is one of biology’s dark secrets that there is no way to decide whether two different species are related closely enough to belong to the same genus. The generic level, and all classification levels in the Linnaean system above the species, are quite arbitrary. Classification of organisms was, and still is, done according to the experience, judgment, and common sense of the classifiers, rather than according to hard and fast rules. A classification is ratified when scientists everywhere use it in their work. Some people are uncomfortable with the lack of objectivity in classification, so a movement exists to abolish Linnaean ranks above the species level. But the convenience and utility of the Linnaean system of ranks and groups, including genera and species, will likely keep it around for quite a while longer.

Type specimens and type species:
In zoological nomenclature, every named species (except for very common and familiar ones, such as Homo sapiens) has a type specimen: a physical specimen against which other specimens may be compared to determine whether or not they belong to that species. Type specimens are usually kept in museums or similar institutions where scientists can readily access them. Likewise, every genus has a type species, the species against which other species may be compared to determine whether or not they belong to that genus. (In dinosaurs, for example, the type species of the genus Tyrannosaurus is Tyrannosaurus rex, and the type specimen of Tyrannosaurus rex is the mounted skeleton on display at the Carnegie Museum in Pittsburgh. If you want to know whether your dinosaur fossil is a Tyrannosaurus rex, you go to the Carnegie Museum and compare it with that skeleton, or you compare it against the original published description of the Carnegie skeleton.)

If, and only if, the type species of a genus is ever placed in another genus, then it carries the name of its genus into synonymy with the other genus, and the older generic name (senior synonym: see Synonymies in List below) becomes the new generic name of the species. In dinosaurs, for example, the type species, Brontosaurus excelsus, of the sauropod genus Brontosaurus Marsh, 1879 was referred to the earlier sauropod genus Apatosaurus Marsh, 1877 by Elmer S. Riggs in 1903. It was then renamed Apatosaurus excelsus, and Brontosaurus was “sunk” as a junior synonym of Apatosaurus. (The type species of Apatosaurus is Apatosaurus ajax, which remains distinct from Apatosaurus excelsus.) Some dinosaur species have been renamed this way several times during the course of dinosaur paleontology. The names of the type species of all the dinosaur genera, as well as of all other dinosaur species and all their renamings, are tabulated by continent in my publication Mesozoic Meanderings #3, which can be ordered by following the instructions at Dinogeorge’s Home page. There are lots of species, renamings, and emendations, too many to be tabulated conveniently at this website; but all of my most up-to-date files of dinosaur species names may be downloaded for free from T. Mike Keesey’s Dinosauricon website.

The type specimen is usually designated when a species is initially described (in which case it is called a holotype specimen); if not, then it may be designated subsequently, in further work on the species (in which case it is called a lectotype specimen). Once designated, the type specimen may be changed only by a formal petition to and subsequent ruling by the International Commission on Zoological Nomenclature (which doesn’t happen very often!). A species without a type specimen is called a nomen nudum and has no formal standing in zoology. Likewise, the type species of a genus is usually designated when the genus is formally described, but it may be designated subsequently if none was designated in the original description. (This occurred sometimes in the old days; nowadays, no genus can be formally created without a named type species.) A generic name informally published without a type species (this occasionally happens in news stories about forthcoming descriptions, for example), or with a type species that is a nomen nudum, remains a nomen nudum without scientific standing until it is formally described in a scientific paper and acquires a valid type species.

For more on naming dinosaurs, see my article “Naming the Dinosaurs,” pp. 128–139 of The Scientific American Book of Dinosaurs, edited by Gregory S. Paul (St. Martin’s Press, November 2000).

Notes for List:
[nomen dubium] = “doubtful name”: generic name the type specimen of whose type species is too incomplete to be distinguished from like material belonging to at least two otherwise distinct species; a nomen dubium genus may be a synonym of another genus, but its known material is not considered complete enough to formalize such synonymy; being a nomen dubium does not invalidate a name but does render equally doubtful any other taxonomic names based on that genus

[nomen ex dissertatione –>] = “name from dissertation”: generic name created in a dissertation; a particular kind of nomen nudum (see below) excluded from availability because dissertations are not considered publications by the International Commission on Zoological Nomenclature; because copies of many dissertations are available by purchase to anyone from University Microfilms International, however, generic names created in them are in fact published in accordance with the criteria of the Dinosaur Genera List, so they are listed here when known, and the publication year is the year the document became available from UMI; a nomen ex dissertatione may change when the author formally describes the genus, in which case the replacement name is indicated

[nomen manuscriptum] = “manuscript name”: formally unpublished name that appears in a manuscript in preparation for publication that has been made publicly available, for example via the Internet; such a name is here counted as a vernacular name, dated the year the manuscript was first made available; if the name is later formally described, its nomen manuscriptum listing is converted into a valid-name listing, with new author(s) and/or date if necessary; if the name is changed upon formal publication, the old vernacular name is retained in the list, along with a pointer to its new valid name

[nomen nudum –>] = “naked name”: generic name lacking a description and/or a type specimen for its type species; indicated name, when given, is the scientific name subsequently applied to the material; a nomen nudum is treated as a vernacular name and is not valid in scientific nomenclature

[nomen oblitum] = “forgotten name”: generic name unused in the scientific literature for at least 50 years after publication and hence at least potentially invalid

[nomen rejectum –>] = “rejected name”: generic name rejected by the International Commission on Zoological Nomenclature in favor of the indicated name; depending on the terms of rejection, a nomen rejectum may or may not be a scientifically valid name

vide = “see”: name attributed to the first indicated author(s) in the paper of the second; the author(s) of the genus is(are) taken as the first author(s), while the date of publication of the name is taken as the date associated with the second author(s)

/ = name preoccupied by the second indicated author(s); indicated name, if given, is replacement name or senior synonym; a preoccupied name is not scientifically valid and must be replaced by a new name when discovered

* = genus not presently considered to be dinosaurian [followed in brackets by its current identification]

Synonymies in List:
[JOS –>] = junior objective synonym of the indicated genus, whose name is to be used in preference; genera are objective synonyms if their type species are based on the same type specimen (this often happens when a replacement name is proposed for a preoccupied name that turns out not to need one); the genus whose name was published first is the senior synonym, the other genus is the junior synonym; the senior synonym becomes the scientific name of the genus unless it has been formally rejected or is otherwise unavailable
[JSS –>] = junior subjective synonym of the indicated genus; genera are subjective synonyms if the type species of one genus has been referred to the other genus or synonymized with a species in the other genus
[PSS –>] = possible subjective synonym of the indicated genus, either junior or senior; usually used here with nomen dubium designation to indicate a better-established genus to which the doubtful genus might be referred
[SSS –>] = suppressed senior synonym: a subjective senior synonym that has been rejected by the International Commission on Zoological Nomenclature in favor of the indicated junior synonym

Note: Different workers have different judgments concerning subjective synonymies and nomina dubia. This List provides the compiler’s present judgment, based on the current literature. Subjective synonymies and nomina dubia designations in this List can and will change from time to time as information from new studies is incorporated. This List is sparing in declaring a name a nomen dubium; others may consider more names to be nomina dubia than this List does.

Generic names appearing in bold italics in this List that remain with no annotations (except perhaps a vide or a PSS) are to be considered unequivocally valid dinosaur names. The synonymies were added as of June 9, 2001, and they have been tuned until they are fully consistent with the compiler’s current publications. On October 14, 2003, when the genera total was 1012 and the visitor count stood at 16,944, the Generic Name Counts table was added to the front end of this document. The generic names are sorted into seven different categories of validity and counted, and the counts are totaled by initial letter and by category. Each name is placed into exactly one category. Vernacular names are either nomina nuda or dissertation names. Genera not presently considered to be dinosaurs (that is, those flagged with asterisks in their listings), are sorted into their own category and are not further subdivided. The genera total for the entire Dinosaur Genera List appears in the bottom right cell of the table.

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