CRABS (BRACHYURA) OF THE GULF OF MEXICO

64 Lawrence W. Powers
Jachowski (1963) noted a similar relationship with Aurelia aurita. Wass (1955)
noted that one female crab was covered with 93 barnacles {Balanus) and Pearse
(1952) reported copepods in the gills and on the carapace of this crab in Texas
waters.
Development of this species in the laboratory was described by Sandifer and
van Engel (1971). Ayres (1938) compared relationships between habitat and
oxygen consumption and Gray (1957) correlated habitat and gill surface area
in this species. Other physiological studies include tolerance to desiccation and
salinity changes (Pearse, 1929) and the physiological activitj^ and neurosecretions
of the pericardial organs (Berlind and Cooke, 1970).
Libinia eniarginala Leach, 1815 (Zool. Misc., 2: 130)
Common Name: Common Spider Crab
Hay & Shore, 1918, p. 456, pi. 38, fig. 6; Rathbun, 1925, p. 311, text-figs. 103-104',
pis. 110-113; Williams, 1965, p. 232, figs. 231, 233H; Felder, 1973a, p. 52, pi. 7,
fig. 7.
Range: Nova Scotia to south Florida; Florida Keys; west coast of Florida to
Mexico. Pacific coast records are probably erroneous (Garth, 1958).
Depth: shore to 49m (to27fm),rarely to 124 m (68 fm).
Habitat: on all types of substrates, but most common on mud and mud-sand
in shallow waters.
Remarks: Gulf records of this species and L. dubia may be confused due to
similarity of the juvenile stages. Wass (1955) compares the key morphological
features of the two species. Listed from Florida (Wass, 1955; Menzel, 1971),
Mississippi (Richmond, 1962; Franks ei al, 1972), Louisiana (Behre, 1950;
Hoese and Valentine, 1972), Texas (Gunter, 1950; Hildebrand, 1954; Parker,
1959; Leary, 1967), Mexico (Hildebrand, 1954), and the Gulf of Mexico (Chace,
1956).
Hildebrand (1954) states that this species is the most common large spider
crab in the westez-n Gulf of Mexico, reversing the numerical dominance relationship
with L. dubia that is found in the eastern Gulf. Like L. dubia, young L.
cmarginala are often associated with the cabbagehead jellyfish, Siomolophus
meleagris. Ovigerous females are present in the western Gulf in February and
are common in July. Hoese and Valentine (1972) collected a crab from the
Chandeleur Islands that was covered with the bryozoan, Bugula. Musick and
McEachran (1972) reported a depth range of 18 to 51 m for this crab in Chesapeake
Bight. Aldrich (1976) reported predaticn by this crab on the starfish,
Asterias. Forward (1977) described shadow responses of the larval stages.
Other studies include: measurement of gill surface area in relation to habitat
(Gray, 1957), biochemical adaptations to temperature variation (Vernberg and
Vernberg, 1968), osmoregulation (Gilles, 1970), physiology of molting (Skinner
and Graham, 1972), sterol synthesis in larval stages (Whitney, 1969), vitellogenesis
(Hinsch and Cone, 1969), sperm structure (Hinsch, 1973), growth biometrics
(Aldrich, 1974), reproductive physiology (Hinsch, 1970), neural fine
structure (Skobe and Nunnemacher, 1970), antennule chemosensitivity (Haz-