6 - Sphaeromatidae::“Cute As Buttons”

234 FLABELL1FERA • SPHAEROMAT1DAE
morphosed. Three pairs of overlapping oostegites arising from pereonites 2-
4 (but S. terebrans has anterior pair rudimentary).
REMARKS The genus Sphaeroma is one of the few sphaeromatids in which the
number of oostegites varies, from the diagnostic three pairs, through two
normal pairs (as in S. terebrans), to having the oostegites completely absent
(as in S. annandalei).
Jacobs (1987) has provided a useful reevaluation of the European, Medi­
terranean, and northwest African species of Sphaeroma and related genera.
Key to species of Sphaeroma
1. Pleotelson posteriorly bluntly triangular, with 4 strong anterior
tubercles
terebrans
Pleotelson posteriorly broadly rounded 2
2. Pleotelson dorsally smooth or with few low tubercles quadridentata
Pleotelson dorsally with numerous strong tubercules walkeri
Sphaeroma quadridentata Say, 1818
Figure 101C
DIAGNOSIS 6 11.0 mm, 9 8.0 mm. Pleotelson anteriorly inflated, some­
times with few low rounded tubercles, posteriorly flattened to concave; pos­
terior margin entire, broadly rounded.
RECORDS New England to Florida; Gulf of Mexico, intertidal to 1 m, often
in pilings and partially submerged dead tree trunks, and commonly associ­
ated with barnacles.
Sphaeroma terebrans Bate, 1866
Figure 10 ID
DIAGNOSIS 6 10.0 mm, 9 11.5 mm. Pereonite 7 with pair of submedian
and pair of lateral tubercles. Dorsal pleon densely tuberculate. Posterior
pleonite with pair of submedian acute tubercles. Pleotelson anteriorly with
submedian pair and lateral pair of tubercles, posteriorly rounded-triangular.