6 - Sphaeromatidae::“Cute As Buttons”

Exosphaeroma Stebbing, 1900
Exosphaeroma alba 229
DIAGNOSIS Maxillipedal palp articles 2-4 produced medially into lobes.
Pereonites 6 and 7 dorsally unarmed. Pleopod 3, exopod biarticulate. 6:
Penes short, separate. Copulatory stylet of pleopod 2 elongate, slender.
Pleotclson lacking strong apical notch. 9: Mouthparts not metamorphosed.
Broodpouch of three pairs of oostegites on pereonites 2-4; oostegites short,
not reaching midline. Brood held in four pairs of internal pouches.
Key to species of Exosphaeroma
1. Pleotelson with posterior margin entire, evenly convex 2
Pleotelson with posterior margin faintly notched or trilobed 3
2. Frontal lamina with length less than 1.5 times greatest width diminuta
Frontal lamina with length almost two times greatest width
productatelson
3. Pleotelson with posterior margin faintly trilobed, and with three low
rounded tubercles anteriorly yucatanum
Pleotelson with posterior margin faintly notched 4
4. Pleotelson posteriorly broadly notched; two rounded submedian
tubercles on inflated midregion antillense
Pleotelson with faint narrow notch posteriorly; lacking dorsal tubercles
Exosphaeroma alba Menzies and Glynn, 1968
Figure 100A-C
DIAGNOSIS 8 2.0 mm, 9 2.3 mm. Frontal lamina anteriorly broadly
rounded, basally slightly wider than midlength. Pleotelson similar in 8 and
9; anterodorsally inflated and unornamented, posteriorly tapering to slight
median notch, seen in dorsal view. Uropodal rami distally shallowly serrate,
exopod 2.5 times longer than wide.
RECORDS Puerto Rico, intertidal to 0.5 m; in algae on rocks, and under
Chiton tuberculatus and C. marmoratus.
alba