Porcellio expansus 'Orange' (Tortosa) Isopods

This is the isopod that looks like a trilobite. Porcellio expansus takes its name from its dramatically widened, flared sides, which give it a broad, flat, faintly prehistoric silhouette unlike anything else in a typical collection, and the Tortosa locality wears that shape in warm, clean orange. At up to nearly 4 cm it is a genuine Spanish giant with real presence in an enclosure. A striking, long-lived display animal for a keeper ready for one.

Introduction

This is Porcellio expansus 'Orange' from the Tortosa locality, described by Dollfus in 1892 and endemic to Catalonia in north-eastern Spain; "Tortosa" names the Catalan city in the Ebro Delta its stock comes from. It belongs to the giant Spanish Porcellio tier alongside the Titan, and sits beside its own sister lines, the standard 'Orange' and the La Senia locality, in the genus. Locality matters here, and Tortosa is known for its warmer, more vivid orange.

Appearance

A large, flat isopod reaching roughly 26 to 38 mm, defined by the expanded lateral margins that flare out from the body and give it its trilobite-like outline. The Tortosa orange is clean and warm, deepening as adults mature, and it reads beautifully against dark bark. It is bold and often out during the day rather than hiding, which for an animal this size makes it a proper display piece. Like all Porcellio it does not conglobate; it scurries and clamps flat rather than rolling.

Care

The one thing that kills Spanish giants is damp, so the setup runs against normal isopod instinct: keep it mostly dry, around 30 to 55% humidity, with strong ventilation and a single small moist corner the colony can visit. Mist that corner sparingly when it dries and never spray the open substrate or the animals. Build a low-moisture, gritty substrate, topsoil used sparingly with a good proportion of sand for drainage, limestone through it for calcium and decaying white-rotted hardwood worked in, kept only 4 to 6 cm deep so moisture cannot pool at the base. Coco coir holds far too much water for this group and is the wrong choice. Give plenty of flat cork bark, which the flared body is built to clamp against.

Diet

A substantial isopod with a substantial appetite: a generous base of hardwood leaf litter and decaying hardwood, vegetable once or twice a week, and protein once or twice a week, which the big breeding females in particular benefit from. Keep several calcium sources available at all times for those large adults, and clear uneaten fresh food promptly to keep the dry setup clean. A springtail culture around the damp corner handles what little mould appears.

Breeding

Expansus breed slowly, as the giant Spanish Porcellio do: growth is gradual, broods moderate and spaced out, and a colony develops over months rather than weeks. The reward for the patience is a group of genuinely impressive adults. Give them the dry-with-a-damp-corner balance, strong airflow, constant calcium and regular protein, start with a group rather than a pair, and leave them to establish undisturbed.

Who is this for?

The Tortosa Expansus suits the experienced keeper who wants a substantial Spanish giant, the collector building an Iberian Porcellio cluster, and the display keeper drawn to that trilobite silhouette. It is not a beginner's isopod and it punishes damp hard, so it is a poor fit for a humid tropical setup or anyone who tends to over-water; the hardy Scaber Mix is the place to learn Porcellio first.

Our stock ships under our live arrival guarantee, in a well-ventilated deli tub inside a double-walled box. We post Monday to Thursday by Royal Mail next day before 1pm, with a 20% overcount in every order. Setup kit is in our accessories range.