They were held back by the fact that a group of species may possibly be related in many different ways.

The examples given below may support both uses of the term "species group."

This is a taxonomically difficult group of very similar species.

After that they moved into the back rooms, where smaller groups of species were gathered.

And between the two groups of seeded species, the dead belt.

Rats from this species group have been used as laboratory animals.

In regards to whether or not members of a species group share a range, sources differ.

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

A number of these genes have been found in the melanogaster species group.

This study identified both particularly sensitive and insensitive groups of species.