How many species of dinosaurs have been named since the first skeletons were uncovered?

The number of species named depends on the text from 250 to more than 1,000 have been mentioned. Suffice it to say that hundreds of dinosaurs have been named since the first skeletons were dug up in the nineteenth century. Between the lack of consensus in terms of species and new fossils found every year, unraveling dinosaur patterns of evolution has been a major obstacle in dinosaur research.

How do the number of known dinosaur species compare to some modern species?

Even if there are truly 700 valid dinosaur species, the number is still less than one- tenth the number of currently known bird species; less than one-fifth the number of known mammal species; and less than one-third the number of known spider species.

How is a dinosaur currently defined using cladistic analysis?

Cladistics is a method of classifying all organisms by a common ancestry, and it is based on the branching of the organisms evolutionary family tree. Those that share common ancestors and thus have similar features fall into taxonomic groups called clades. Thanks to cladistic analysis, all dinosaurs were found to have many unique characteristics in common. In fact, these reptiles are defined as a monophyletic group descending from a common ancestor. And with the development of modern cladistic testing, true dinosaurs can be distinguished from their closely related, but non-dinosaur, contemporaries.

Using cladistic analysis, a reptile is a dinosaur if it has several specific characteristics in its fossilized skeleton, including some of the following: an elongated deltopectoral crest on the humerus; three or fewer phalanges in the fourth finger of the hand; the absence of a postfrontal bone; a crest on the tibia; three or more sacral vertebrae; a fully open hip socket; a ball-like head on the femur; and a well-developed ascending process on the astragalus, fitting on the front face of the tibia. In other words, identifying a dinosaur has a great deal to do with its skeletal anatomy. Although these characteristics are very technical, the main point is that scientists now have a clear test to determine if a fossil skeleton is truly that of a dinosaur.

How are dinosaurs named?

Dinosaur names come from a number of places, but in general, they are named after a characteristic body feature (for example, the Hypsilophodon, or high-crowned tooth); after the place in which the first bones were found (for example, the Muttaburrasaurus); or after the person(s) involved in the discovery (for example, the Leaellynasaura).

In most cases, the names include two Greek or Latin words, or even combinations of the words. For example, Tyrannosaurus rex is a combination of Greek and Latin translated as king of the tyrant lizards. Overall, the two names, known as the genus and species names, are used by biologists to describe all organisms on Earth, such as humans (Homo sapiens sapiens), domestic dogs (Canis familiaris), or rattlesnakes (Crotalus horridus).

How did dinosaurs evolve?

Its hard to determine which charts are right or wrong when it comes to dinosaur evolution, mainly because, since 1980, over 150 evolutionary trees of dinosaurs have been published, most of them looking at small groups of species.

How are dinosaurs classified?

The following table explains how dinosaur species are organized by order, suborder, infraorder, and family.

Classifications for Dinosauria*

*This is only one representation of how dinosaurs may be classified. There are actually many other dinosaur classifications, depending on the scientific study, and there will continue to be more as fossils are discovered and interpreted.