#malacostraca

Petrolisthes violaceus, a species of porcelain crab, in Los Molles, Chile

(Sources - 1, 2, 3, 4)

Order: Isopoda

Common Name: “isopod” is most commonly used to encompass all members of the order, but terrestrial species are commonly called “woodlice”, “pillbugs”, “rollie-pollies”, and various other names

Suborders*: 11 - Asellota (30 families), Calabozoidea (2 families), Cymothoida (28 families), Limnoriidea (3 families), Microcerberidea (2 families), Oniscidea (33 families), Phoratopidea (1 family), Phreatoicidea (6 families), Sphaeromatidea (7 families), Tainisopidae (1 family), and Valvifera (12 families)

*(I am not listing families as, as you can see above, it would take up too much space)

Anatomy: rigid, segmented exoskeleton; carapace is reduced to a "cephalic shield" covering only the head; two pairs of antennae; seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration; females brood their young in a marsupium; typically flattened dorsoventrally (ie broader than they are deep), although many species deviate from this rule, particularly parasitic forms

Diet: some eat dead or decaying plant and animal matter, others are grazers or filter feeders, a few are predators, and some are internal or external parasites

Habitat: aquatic species live in benthic habitats in both freshwater and marine environments; terrestrial species live in cool, moist environments

Evolved in: Late Carboniferous

Propaganda under the cut:

Peacock Mantis Shrimp (Odontodactylus scyllarus) with eggs, family Odontodactylidae, Tulamben, Bali, Indonesia

I love crawdads, thank you for the request!

Gippsland Burrowing Crayfish Engaeus hemicirratulus

A crayfish found in south Victoria, Australia.

Morenas negras (Muraena augusti), franja marina Teno-Rasca, Tenerife, España, 2022-01-09

📍 Location: Nags Head, North Carolina

🗓 Date: May 23, 2025

🐾 Media: Image

🌿 Species: Ocellate Lady Crab (Ovalipes ocellatus)

📝 Notes: Fast-moving marine crab found along sandy beaches and shallow coastal waters of the western Atlantic. Recognizable by its pale shell covered in circular “eye-like” spots (ocelli) and long legs adapted for rapid sideways movement and shallow burrowing.

Often encountered in surf zones, tidal flats, or just beneath wet sand. Capable of burying itself quickly when disturbed.

Carapace only.