Marine Invertebrates

Amphipod

Amphipod (Amphipoda): biology, diversity and ecological roles

Bivalve

Bivalve (Bivalvia): two‑valved molluscs — overview, anatomy, ecology, uses

Bivalves are aquatic molluscs with two hinged shells. This article summarizes their anatomy, feeding, habitats, reproduction, evolution, ecological roles and human uses.

Chelicerata

Chelicerata: anatomy, evolution, diversity and ecological roles

Chondrophore

Chondrophore (Porpitidae): colonial, surface‑dwelling hydrozoans

Coleoidea

Coleoidea — the modern shell‑less cephalopods

Coleoidea is the cephalopod subgroup that includes octopuses, squids and cuttlefish, distinguished by reduced or internal shells, advanced nervous systems, and diverse marine ecolo