During this period, the remains of small hollow-crested duckbills were described as their own genera and species.
The genus has had a complicated taxonomic history, in part because small-bodied crested hadrosaurids now recognized as juveniles were once thought to belong to their own genera and species.
Thus, the endemics are often treated within their own genera.
Furthermore, Mabuyidae apparently refers to the clade containing Chioninia, Dasia, Mabuya, Trachylepis, with each of these genera placed in its own subfamily (Chioniniinae, Dasiinae, Mabuyinae, and Trachylepidinae).
As a consequence of this, Zombia and related genera were places in their own tribe, Cryosophileae.
Instead, he published a broad analytical study where he proposed a new plan of classification for the Eocene mammals, in which he discarded Marsh's genera in favor of his own.
Aristolochiaceae (including Lactoris, which used to be in its own family, Lactoridaceae) contains 480 species in 5 8 genera distributed in the tropics of both hemispheres, and several genera occur in the temperate zone.
This flora makes up its own floristic region and includes more than 1,500 genera, 30 percent of which are native nowhere else in the world.
These authors concluded from own and literature data for 43 species, 33 genera, 23 25 families and 9 orders of the Agaricomycetes that their ballistospores exhibit electric loads.
His own exegesis applies a variety of techniques: categorizing genera and species, distinguishing between essential and non-essential qualities, asserting the symmetry of relation, understanding the law of contradiction, recognizing valid and invalid syllogisms, as well as logical fallacies.
Scientific efforts to systematize the whole living world such as those by Linnaeus revealed to be never ending and unconclusive, leading to put in debate their own fundamental concepts ("does a species really exist? Do genera really exist?", Chapter 5).
