Spider crab

Anatomy
The Portly Spider Crab (Libinia emarginata), though it looks somewhat frightful because of its spider-like appearance, is, for the most part, a quite harmless crab, whose round carapace is normally around 4". They are muddy brown or khaki in color, and have a long leg span of about 12". This crab moves slowly and has fairly weak, small claws. According to the Identification Guide to Marine Organisms of Texas, the body is "tubercled with spines and bumps" and has a "row of 8-9 spines down the center of the carapace." The spider camouflages by coverings of algae, shell, seaweed, and detritus.

Habitat
Portly Spider Crabs are found in bays and the Gulf from "Nova Scotia to the Florida Keys and through the Gulf of Mexico". Though they can be found in all substrates, they are usually found in muddy, shallow waters, such as those waters found in Cedar Key, Florida, from the shore to usually no more than 160ft.

Reproduction
According to Gertrude W. Hinsch, "Ovigerous females were collected from early June to early September. Females are apparently able to produce at least 3-4 consecutive broods of 25 days development each during a breeding season." On Wikipedia, the "L. emarginata male show an unusual "obstetrical behavior", in which gravid females who are about to release their larvae are held behind the male, and aggressively protected.".

Behavior
The Portly Spider Crabs show an usual behavior in that they are forward-walking crabs, rather than the normal side-walking.