Wikipedia:WikiProject Palaeontology/Guidelines

Which articles should be created

Editors sometimes wonder whether it is necessary to create a separate article for every species in a genus. In the case of monospecific genera, the general WP:TOL guideline is to create a single article at the genus level. For example, an article exists at Saadanius and a redirect at Saadanius hijazensis. Exceptions exist when the genus name needs WP:disambiguation.

It has been agreed that species should generally be redirected to a genus page, as there is usually much less info available for prehistoric than extant species to create substantial articles. If there eventually is enough text about each species, they may have a separate section in the genus article; see Cimoliopterus for an example. If a single species is well-known enough and eventually generates enough content to make the genus article too WP:too long, a separate species article can be created; other species in said genus should only be split from the main article when their texts grows too long as well (as is for example the case with many mammoth species).

In the case of genera that contain multiple species, a degree of common sense is necessary. Wikipedia:MERGE lists three reasons that it may be appropriate to combine the species into a single page:

• There may be a substantial overlap in the content of the articles (for instance, if the species are found in the same locality and are morphologically and biologically very similar);
• There may be very little text that can be written about individual species (if a species is very similar to others in its genus and only differs in minor featutres, an article may simply read "Orthoconus grandi is a species of Orthoconus whose shell is greater than 2 mm in height").
• It may be necessary to have context from a broader article in order for readers to understand the species' context. For instance, the phylogenetic context of Halkieria requires lengthy explanation, so in this instance it is appropriate to have multiple genera in a single article.

Extinct species placed in extant genera should normally receive separate articles, since fossil-specific information such as taphonomy, site geology, repositories, collectors, paleorange and paleoecology cannot easily be covered in the genus article.

Dubious genera warrant separate articles and should not be redirected. Dubious species and species that have been incorrectly placed in a specific genus should be redirected to the closest higher level taxon it can be assigned to. Articles should not be created for any specimens or taxa that have not been assigned a valid scientific name.

How to categorize articles

1. Categories are to be based off of the established mainspace articles and their names following WP:C2D and WP:C2C and WP:CROSSCAT
   • Mainspace articles can include topics such as taxonomic clades, formations, geologic time units, scientists, and lists etc.
   • This also means all categories should follow the exact name as the mainspace article (ie. "Ornithischia" rather than "ornithischians")
2. Where categories exceed a reasonable article count they may be split following WP:DIFFUSE into the main category and subcategories
   • This "reasonable article count" lies between 200 and 400 articles, as categories under default preferences display up to 200 pages on a single list
   • Diffusion should follow boundaries between WikiProjects or established mainspace articles to maximize scope and consistency across and within projects
     • ie. Category:Campanian diffused into Category:Campanian life and/or Category:Campanian dinosaurs as the boundary between WP:GEO and WP:PALEO and WP:DINO
3. Container categories should be limited to categorization by the topics seen in for example WP:BIRD and WP:MAMMAL: by location, by classification, by year of description, and by geologic time.
   • As geographic locations change over time, location should reference modern geography as in WP:BIRD and WP:MAMMAL with both continent and country categories acceptable
   • "[Taxon] by classification" categories are not needed if nested taxonomies are used as exemplified by Category:Saurischia
4. Creation of categories that do not follow the above, or are questionable, should be discussed prior, so that categorization can stay consistent and understood
5. Articles should be categorized within the least inclusive category that exists for each topic it can be categorized according to, subject to discretion
   • ie. A taxon of uncertain age or multiple age ranges may be categorized according to epoch, period, or era depending which is considered more "useful" by the editor
6. Categories themselves should be categorized according to increasing inclusivity while following the same guideline for creation
   • ie. Category:Chaoyangsauridae, a taxonomic clade category, is a child category of Category:Ceratopsia, a taxonomic clade category, but not Category:Dinosaurs of China, a location category, despite the mainspace article Chaoyangsauridae being categorizable within both
   • Exceptions exist for categories that serve as both containers for their respective WikiProjects as well as a mainspace article (eg. Category:Birds) which should be parent to all categories that reflect content under the scope of their WikiProject, including container categories