Question

A group of animals called the horseshoe crabs also appear in the Ordovician, but unlike the eurypterids, these animals survived all five mass extinctions! They're very good at what they do! The horseshoe crabs belong to a group called the chelicerata. What is the main synapomorphy (shared, derived trait) of the chelicerates?

a. Jointed legs
b. Radial symmetry
c. Notochord
d. Limbs on the mouth for feeding

Answer 1

The main synapomorphy, or shared derived trait, of the chelicerates, is the presence of chelicerae.

Step-by-step explanation:

Chelicerae are specialized appendages or limbs that are located in front of or around the mouth. They typically take the form of pincer-like structures. These appendages are used for a variety of functions, such as feeding, defense, or capturing prey. In chelicerates, including horseshoe crabs, spiders, scorpions, and ticks, the presence of these chelicerae is what makes them stand out from other arthropod groups.

Answer: d. limbs on the mouth for feeding.