Records and Descriptions of Epitoniidae (Orthogastropoda: Epitonioidea) from the Deep Sea off Northeastern Brazil and a Checklist of Epitonium and Opalia from the Atlantic Coast of South America
Table 1
Main differences in morphology of mouthparts and other structures involved in food acquisition.
Structure
Gammarus pulex
Gammarus fossarum
Echinogammarus berilloni
Antennal flagellum
Annuli medio-laterally broadened; each with a row of 12 posteriorly directed setae together building a flag-like brush
Each annulus with a group of 2–5 simple setae on median and lateral side
Antero-posteriorly flattened and therefore broadened; setation sparse; setae short
Cuspidate setae on distal margin of basipodal endites of maxillula
Lateral setae with three finger-like secondary spines
2-3 lateral setae distally flattened and broadened like chisels with three humps on distal edge
4 lateral setae with thickened shafts, distally flattened; distal margin blunt with 2-3 humps
Setation of carpus and propodus of 2nd gnathopod
Long and closely arranged setae with curled distal ends
Long and closely arranged setae with curled distal ends
Less numerous and shorter setae than in G. pulex and G. fossarum
Third uropod
Endopod 3/4 as long as exopod; plumose setae on medial and lateral margins of endopod and exopod
Endopod half as long as exopod, plumose setae on median margin of endopod and exopod; simple setae on lateral margin of exopod
Endopod very short; only simple setae on lateral and median margin of exopod