| Pachygrapsus transversus,
also known as the Mottled Shore Crab is a small rocky intertidal crab
inhabiting shorelines of tropical regions in the Atlantic,
eastern Pacific, and the Mediterranean (Vaccaro). Like many other
crab species they have also been known to be transported to new
locations in the bilge water of cargo ships (Vaccaro). It
typically reaches a size of 2 cm in width and can be
identified due to its square shape and single tooth on the
front of the carapace (Ruppert). The coloration of these crabs is
brownish-green with striping on the anterior end of the carapace
and a mottled appearence on the legs and rest of the body. P. transversus
has a somewhat different development from other similar crab species.
The species breeds in the summer and the larval stage is quite
long with an estimated development time of four months (Flores).
The juveniles develop in about 2-3 months during the winter due
to the milder climates they live in (Flores). Due to this, they
are able to molt during the winter unlike many other crabs which gives
them an advantage as an adult once spring and summer comes (Flores).
This life cycle helps to explain why P. tranversus is so prevalent in warmer intertidal waters. P. transversus
is thought to be a fairly recent invader of the Mediterranean
(Vaccaro). This dispersal is hypothesized to have occurred due to
attachment of larvae to the outside of wooden ships during the
beginning of long distance shipping (Vaccaro). |
