Every name on this site's Index -- from Tyrannosaurus to the most obscure single-tooth genus -- went through the same formal process, but the evidence behind that name can vary enormously. Understanding that difference is the key to reading a stub page correctly.
It starts with a type specimen
When a paleontologist believes they've found a new genus, they designate one fossil -- the holotype -- as the permanent physical reference for that name. Every future comparison, every "is this the same animal or a new one" debate, gets checked against that specific specimen, usually held in a named museum collection. The name is published in a peer-reviewed paper alongside a formal description of what makes the specimen distinct, following rules set by the International Commission on Zoological Nomenclature (ICZN) -- the same body that governs naming for all animals, not just dinosaurs.
This is why a name like Tyrannosaurus rex is really two names in one: a genus (Tyrannosaurus) and a species (rex), together forming a binomial. It's also why you'll sometimes see old names quietly retired -- if two genera turn out to be the same animal, the earlier-published name almost always wins, and the newer one becomes a junior synonym.
Most names come from body fossils -- but not all
The overwhelming majority of genera on this site are diagnosed from actual skeletal material: bone, teeth, sometimes skin impressions. That's the default assumption for any named genus. But two categories of name work differently, and they're worth knowing how to spot.
Ichnotaxa -- names from trace fossils. Footprints, trackways, burrows, even fossilized nests can be distinctive enough to earn their own scientific name, even with zero body fossil ever recovered. These are called ichnotaxa (from the Greek ichnos, "track"), and they follow a parallel naming system precisely because a footprint can't be matched to a specific skeletal genus with certainty -- a single trackmaker's footprints, and a related species' footprints, can look identical. You can usually spot an ichnotaxon by its name: many end in -ichnus, -pus, or similar footprint-referencing suffixes. An ichnotaxon is not a "lesser" or fake dinosaur -- some are important evidence for animals whose body fossils have never been found in that region. But an ichnotaxon name should never be read as if it names a distinct skeletal animal alongside its "real" body-fossil relatives; it names the tracks themselves.
Nomen dubium -- names too uncertain to use confidently. Sometimes the original fossil material used to name a genus is too fragmentary, too damaged, or too generic to reliably distinguish it from other known animals. Paleontologists call this a nomen dubium ("doubtful name"). The name still exists in the historical record and still gets cataloged, but it isn't treated as a confidently valid, distinct genus the way a well-supported name is.
What this means when you're browsing
Because of this, not every name on the Index carries the same evidential weight. A stub page with no summary yet might simply be a genus this site hasn't gotten to researching. But a page explicitly flagged as trace-fossil-only or dubious is telling you something different: the science itself is less settled, not just the write-up. Where we know a genus falls into one of these categories, we say so directly on its page, rather than presenting every name with the same false confidence.
This is also why well-documented, thoroughly studied dinosaurs surface first when you browse the Index by default -- not because obscure or uncertain names matter less, but because "how much do we actually know about this one" is a genuinely different question from "does this name exist in the fossil record." Searching for a specific name by title always finds it regardless of how much is currently written about it.