CRABS (BRACHYURA) OF THE GULF OF MEXICO

The Freshwater Crabs
Crabs of the Gulf of Mexico 87
The familial name, based on the genus Potamon Savigny, 1816, was corrected
from the original Potamonidae of Ortmann by an ICZN decision (Opinion 712,
p. 342, in 1964). A revision of the freshwater crabs by Bott (1955b) split this
family into two: the Pseudothelphusidae and the Trichodactylidae. Various
other schemes for classification have been proposed (Pretzmann, 1965; Bott,
1968; Smalley, 1970). Gulf region species are confined to northern Cuba and
southern Mexico, but insufficient material and information is available for most
species to yield accurate ranges or to present a satisfactory organization of taxonomic
relationships. Because these crabs are inhabitants of rivers, lakes, and
caves, species ranges tend to be restricted to small areas; several are known only
from a single type specimen. Species occurring in the center of a land mass,
such as Potamocarcinus (Typhlopseudothelphusa) mocinoi in caves near Comitan
(Chiapas) Mexico (Rioja, 1952) could be assigned to a coastal region based
on watershed drainage patterns. The Cuban species listed by Chace and Hobbs
(1969) are not localized to either the Gulf or the Caribbean side of the island
in the records cited. For these reasons, these crabs are not included in the present
work. Further references, including some older systematic papers, can be found
in the papers cited above. There exists a clear need for more extensive work on
this group of brachyurans.
Family XANTHIDAE Dana, 1851
This is a large family of crabs (about 1000 species and more than 130 genera)
that has traditionally posed a number of taxonomic problems. Many of the
species are small in size and appear morphologicallj^ similar. Individual variability
and the large number of closely related species has often made definitive
identification difficult, so that earlier collection records must be used cautiously.
Rathbun (1930) did not subdivide her account of the xanthids into subfamilies.
Guinot (1971) offers a number of systematic revisions and she comments
at some length on affinities, but she also avoids listing the 51 genera that she
treats under subfamilies. The same procedure is followed here, by arrangement
of the 33 Gulf genera in alphabetical order, without regard for proposed affinity
within the family. The xanthids are currently being revised by various workers
around the world, so that a better organized and more accurate representation
of this family should be forthcoming.
Aclaea de Haan, 1833
Aclaea acantha (H. Milne Edwards, 1834) (Hist. Nat. Crust., vol. 1, p. 379)
Rathbun, 1930, p. 261, pi. 105, fig. 5, pi. 106, figs. 1-2; Rathbun, 1933, p. 57.
Range: Bahamas; Florida Keys and Dry Tortugas; northwest coast of Cuba;
Jamaica; Haiti; Puerto Rico; Guadeloupe; St. Bartholomew; Fernando de Noronha,
Brazil.
Depth: surface to 22 m (tol2fm).