As its name suggests this
crab has very long legs. It has a very triangular shell and it looks like
a Daddy Long-legs.
If it is caught in a net
or stranded at low tide, it resembles a crumpled up twig. However, when
under water it swims with a curious bicycle-like motion. It often places
weed all over its legs and shell which gives it its other name of Decorator
Crab. There are several species of crabs in the genus Macropodia
and differentiating them is very tricky.
Although not clear from the
photographs, all the spider crabs have ten legs including the major claws.
Photograph by Brian May
these species are so close that it is near impossible to separate them
in the sea and rockpools and difficult in captivity
and difficult with dead specimens under a magnifying glass.
Spain,where I worked on it, Dictyota linearis is the alga of choice
of Guam Marine Laboratory
the specimens I have collected (hundreds) have not been decorated with
weed, and associated with hydroids. My collection are is on the shore off
the Sussex coast, English Channel, e.g. Kingston
Beach, Shoreham-by-Sea, where it is common just below Chart
Datum in autumn.
& 30 Ocotber 2014
Long-legged Spider Crabs
were discovered on Maenporth
Cornwall, mostly decorated with red seaweed but some of them in the rockpools
had green seaweed atatched to their legs and carapace.
they are six metre plus high tides, the water does not recede every far
only down to 0.8 metres above Chart Datum,
so the rockpooling was only to collect a few
prawns for the wrasse in my home
appearance of four large Long-legged
Spider Crabs (1)
was unexpected, although they have been caught in July before.The largest
specimen measured 18 mm from the rear of the carapace to the eyes but the
spread of legs and claws was 100 mm.
of the Seashore (Link)
Information wanted: Please
send any records of this crab, with location, date, who discovered it,
how it was identified, prevalence, common name and any other details to
Project EMail Glaucus@hotmail.com
All messages will receive a reply.