The Sally Lightfoot (Percnon gibbesi)

It is a species of brachyuran crab that is normally found in tropical and subtropical regions, mainly in the Atlantic Ocean and the Pacific Ocean. It is characterized by its flat body, about 3 to 4 cm long, long, thin legs, and a distinctive coloration that includes blue, green, and reddish tones. The spider crab is an agile and fast species, adapted to move along rocky surfaces in shallow waters between 0 and 4 meters deep.

It is native to the coasts of the Atlantic Ocean (from Florida to Brazil and from Madeira to the Gulf of Guinea) and the Pacific Ocean (from California to Chile). Experts consider it to be an invasive species in the Mediterranean Sea, where it was first detected in 1999. Humans have facilitated its expansion in the region, which can be attributed to transport in ballast water (used in maritime navigation) and fishing nets, as well as to its larvae carried by marine currents.

This crab prefers rocky habitats, where it can protect itself from predators such as octopuses. It is mainly herbivorous, feeding on algae, although it can occasionally consume small crustaceans or fish. It reproduces in summer, and the females release larvae that become part of the zooplankton.

As an invasive species, Percnon gibbesi can compete with other native crab species such as Pachygrapsus marmoratusAlthough there is no clear evidence of serious ecological damage, their presence could alter the natural balance in some ecosystems of the Mediterranean Sea.

Illustration made as part of the mini course Illustrating Crustaceans. Iara Chapuis was in charge of teaching it during the 1st International Congress of Online Scientific Illustration by Illustraciencia.

Year: 2021
Technique: Watercolor illustration and digital layout.
Illustration type: Scientific.
Type of project/Client: Course project.