evolutionary grade

The term 'evolutionary grade' is sometimes used for such groups.

An evolutionary grade is a group of species united by similarities.

The group is thus an evolutionary grade rather than a clade.

He also argued that human fossils could be assigned a date, a race, and an evolutionary grade.

Labyrinthodonts are an evolutionary grade, and the group is no longer a term in taxonomy.

Instead, the three bryophyte groups form an evolutionary grade of those land plants that are not vascular.

Paraphyletic taxa will often, but not always, represent evolutionary grades.

In other words, they are a evolutionary grade that is thought to have given rise to both ammonoids and coleoids.

It is probably an evolutionary grade, not monophyletic.

Evolutionary grade 1959: a level of evolutionary advance, in contrast to a clade.

Their name may still be very useful to biologists, because its members may be an important evolutionary grade.

Evolutionary grades, being united by gross morphological traits, are often eminently recognizable in the field.

The group is an evolutionary grade (a polyphyletic or paraphyletic group) of species which look rather similar.

Therefore, at its widest extent, the order Insectivora represented an evolutionary grade rather than a clade.

"Plagiaulacida" is paraphyletic, representing the more primitive evolutionary grade.

In phylogenetic nomenclature evolutionary grades (or any other form of paraphyly) are not accepted.

These labyrinthodonts are often grouped together as the order Ichthyostegalia, though the group is an evolutionary grade rather than a clade.

The name of a wastebasket taxon may in some cases be retained as the designation of an evolutionary grade, however.

"Hypsilophodontidae" and "hypsilophodont" are better understood as informal terms for an evolutionary grade, not a true clade.

More recent research suggests that this is not a distinct clade-a group of closest relatives and nothing else-but an evolutionary grade instead.

Below is a cladogram from the analysis, with bold lines representing the evolutionary grade of acanthodians:

The protists were understood to be "primitive forms", and thus an evolutionary grade, united by their primitive unicellular nature.

Lizards as a unit represent an evolutionary grade, defined by their retention of limbs relative to snakes and Amphisbaenans.

Some studies consider the family a paraphyletic group, representing an evolutionary grade of basal epicynodonts rather than an actual clade.

With the rise of phylogenetic nomenclature, the use of evolutionary grades as formal taxa has come under debate.