#malacostraca

[snototter]

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

by Diego Gutierrez

[saritawolf]

Atlantic Ghost Crab (Ocypode quadrata) - (c) SaritaWolf - please do not repost

[bestanimal]

Round 3 - Malacostraca - Isopoda

(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

Do you have a favorite in Isopoda?

One or more of my favorite animals is in Isopoda

I love at least one or more of these animals

I like at least one or more of these animals

I am neutral about all of these animals

I dislike all of these animals

Voting ended onAug 24, 2025

Propaganda under the cut:

Some species of isopod are able to roll themselves into a ball as a defense mechanism or to conserve moisture, particularly the terrestrial species of the family Armadillididae, the “pillbugs”.

The Baltic Isopod (Idotea balthica) is the first known underwater pollinator, and the first known animal to help algae reproduce. It is specifically a pollinator of the Irish Moss (Gracilaria gracilis) algae.

Woodlice (suborder Oniscidea) are one of the few lineages of crustacean to have transitioned into a fully terrestrial environment.

While some isopod species are kept purely as pets, some can also be used as an addition to bioactive terrariums, due to their ability to break down decaying organic materials.

The Giant Isopods (genus Bathynomus) (see gif above) are deep sea isopods that include the largest isopods in the world, including Bathynomus giganteus and kensleyi. These species reach a typical length between 19 and 36 cm (7.5 and 14.2 in), with the largest confirmed being around 50 cm (20 in) long.

[herpsandbirds]

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

photograph by Ronen Avigdor

[have-you-seen-this-animal]

i dunno if youve done it before, but what about Cambarellus Diminutus, AKA the least crayfish. Its the smallest crayfish out there with males reaching only 2.5cm and females getting up to 4cm at times, usually only around 3 though.

I love crawdads, thank you for the request!

Have you seen the least crayfish (Cambarellus diminutus)?

I have now

Yes, in photos/videos

Yes, irl

I'm not sure

Voting ended onFeb 6

The first photo is thanks to Chris Lukhaup!

[every-day-creechur]

Automate anacanthopus

A shrimp from the South China Sea. The "pistol shrimp" are characterized by having an enlarged and highly modified chelae ("claws") on one leg of their first pair, which is used for various purposes.

image by Arthur Anker, et al.

[wikipediapictures]

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

“Moray eels (Muraena augusti) and a cleaner shrimp (Lysmata grabhami), Teno-Rasca marine strip, Tenerife, Spain. It belongs to the family of moray eel and is endemic of the Canary Islands, Madeira and Azores. It is non-migratory, and dwells at a depth range of 0 to 250 metres (0 to 820 ft), most often at around 0 to 50 metres (0 to 164 ft). Muraena augusti is active during the night and hides in holes or crevices during the day. It can reach up to 100 centimetres (39 in) length and is a carnivore that feeds on small fishes, shrimps and crabs. Like all other moray eels their vision is poor but their sense of smell extraordinary.” - via Wikimedia Commons

[flighty-flycatcher]

📍 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.

🔗 iNaturalist: https://www.inaturalist.org/observations/283457165