Prosomas

Part of speech: noun

Definitions

1. The anterior part of an arthropod's body that includes the head and thorax fused into a single segment
2. A zone in certain crustaceans where the head and trunk are not distinctly separated
3. A region within some invertebrate animals that serves various physiological roles related to head-like structures

Etymology: "Prosomas" is the plural of "prosoma", the fused head-and-thorax region found in spiders, scorpions, horseshoe crabs and their relatives. The word is built from two Greek parts: "pro", meaning "front", and "soma", meaning "body", which comes from the Ancient Greek "sōma". Put together, the name describes the front section of the animal's body, the part that holds the head and the parts that sit on it. Because the term is a straightforward combination of familiar Greek elements, it needs no hidden story: a zoologist simply joined "front" and "body" to name a body region that had no existing label. The same pattern lies behind the paired term "opisthosoma", the rear section, which uses "opistho", meaning "behind".

Synonyms: cephalothoraxes