CRABS (BRACHYURA) OF THE GULF OF MEXICO

124 Lawrence W. Powers
Habitat: commensal in a variety of bivalve molluscs; young of both sexes and
often adult males are free-swimming; most common in the mantle cavities of
mussels, Mytilus edulis; in tubes of the polychaetes Arenicola and Chaetopterus
(C. pergamentaceus and C. variopedatus); from mud, sand, shell and gravel
substrates. Other molluscan hosts include: Atrina rigida, A. seminuda, A. serrata,
Anomia simplex, Argopecten gibba, A. irradians, Cyrtopleura costata. Modiolus
modiolus, M. tulipa, Mya arenaria, and Placopecten magellanica.
Remarks: This species has a large literature, catalogued by Schmitt, McCain
and Davidson (1973). Larval stages were described by 0. W. Hyman (1924),
Aikawa (1937) and Costlow and Bookhout (1966b). Life history data is provided
in MacGinitie and MacGinitie (1968) and by Christensen and McDermott
(1959). Caine (1975) studied feeding behavior and physiology and Kruczynski
(1975) measured food intake and digestion. Pearce (1964) described reproductive
aspects. Larval shadow responses were studied by Forward (1977) and behavior
in relation to hosts was described by SasUy and Menzel (1962) and by
Eidemiller (1969). The effects of this crab on the growth and biology of its
scallop hosts were studied by Kruczynski (1971, 1972). Sandifer (1973) commented
on larval ecology in Virginia and Fotheringham and Brunenmeister
(1975) described this crab as it occurs in the Gulf of Mexico. Regional lists include
Florida (Wass, 1955; Tabb and Manning, 1961; Abele, 1970; Menzel,
1971; Godcharles and .laap, 1973) and Texas (Leary, 1967). Listed from Brazil
by Rodrigues da Costa (1971) and Coelho and Ramos (1972).
Pinnotheres inoseri Rathbun, 1918 (Bull. U.S. Nat. Mus. 97: 94)
Rathbun, 1918, p. 94, text-fig. 47, pi. 21, figs. 3-4; Schmitt, McCain & Davidson,
1973, p. 58.
Range: west coast of Florida.
Depth: 1.5to5.5m (lto3fm).
Habitat: commensal in sea squirts (tunicates) and from the brachial cavity of
an ascidian, Polycarpa obtecta; off rocky bottoms with grass and thin layers of
sand and mud.
Remarks: Rathbun (1918) did not list sea squirts as commensals, only as
present in the dredges in which the crabs were found. Pearce (1966) provided
information on life histoiy and Hartnoll (1964a) described a larval stage. Listed
from Florida by Godcharles and Jaap (1973), including data from the collection
locality.
Pinnotheres ostreum Say, 1817 (J. Acad. Nat. Sci. Philadelphia 1: 67)
Common Names: Oyster Crab; Common Pea Crab
Hay & Shore, 1918, p. 543, pi. 35, fig. 9; Rathbun, 1918, p. 66, text-fig. 30, pi. 15,
figs. 3-6; Williams, 1965, p. 203, figs.. 187-189; Felder, 1973a, p. 75, pi. 10, figs.
12-14; Schmitt, McCain & Davidson, 1973, p. 61.
Range: Massachusetts to south Florida; Texas; northwest Cuba; Guadeloupe;
Pernambuco to Santa Catarina, Brazil.
Habitat: parasitic in oysters and present in other bivalve molluscs, including:
Crassostrea virginica, C. rhizophorae, Anomia simplex, Mytilus edulis, and