Members of genus X, a hypothetical taxon of invertebrates, have antennae with a variable number of segments. Species A and B have 10 segments; species C and D have 9 segments; species E has 8 segments. In all other genera in this family (including genus Y), all species have antennae with 10 segments. Which of the following character states is a synapomorphy that would be useful for determining evolutionary relationships within genus X?
A) 10-segment antennae in species A and B
B) 10-segment antennae in genus Y and in two species of genus X
C) Antennae with fewer than 10 segments in species C, D, and E
D) 8-segment antennae in species E
E) Both c and d

Question

Quizplus · Accepted Answer

A synapomorphy is a shared derived character state. Antennae with fewer than 10 segments in species C, D, and E is a derived trait within genus X, distinguishing these species from those with the ancestral 10-segment condition.

Members of Genus X, a Hypothetical Taxon of Invertebrates, Have