6 - Sphaeromatidae::“Cute As Buttons”

Thermarcturus Paul and Menzies, 1971
VALVIFERA • IDOTEIDAE 255
DIAGNOSIS Pereonite 1 not fused with cephalon. Pereonite 4 subequal in
length to pereonite 3, not markedly elongate. Pereopods 2—4 having dactyli
but lacking elongate setae. Body cylindrical, flexed between pereonites 4 and
5. Pleon consisting of two free pleonites plus pleotelson.
Thermarcturus venezuelensis Paul and Menzies, 1971
Figure 107H
DIAGNOSIS 9 4.5 mm. Cephalon, all pereonites, and anterior two pleonites
each with submedian pair of dorsal tubercles, those on pereonites 2 and 3
broad and expanded. Pleonite 2 with pair of bulbous lateral swellings, pos­
terior margin triangular. Pleotelson with lateral shoulder anteriorly, posteri­
orly triangular.
RECORDS Off Venezuela, 95 m.
REMARKS Only the holotype (which seems to be lost) is known of this spe­
cies. Considerable uncertainty exists regarding some of the features.
Family Idoteidae Fabricius, 1798
Subfamily Idoteinae Dana, 1852
DIAGNOSIS Flagellum of antenna either multiarticulate; clavate, i.e., with
large basal articles and with or without one to four reduced distal articles; or
Key to genera of Idoteinae
1. Antennal flagellum multiarticulate Idotea
Antennal flagellum clavate 2
2. Pereopod 4 reduced, considerably smaller than pereopods 3 or 5 .... 3
Pereopod 4 not reduced, of similar size to pereopods 3 and 5
Erichsonella
3. Pleon consisting of three complete and one incomplete pleonites plus
pleotelson Cleantioides
Pleon consisting of two complete and two incomplete pleonites plus
pleotelson Miratidotea