Diagnosis: rostrum in adults not reaching scaphocerite end, shorter than carapace (brooked at south Atlantic examined specimen); branchiostegal spine strong, flared outwards, with distinct carina extending backwards on to carapace for three times the spine length (Figs.
Diagnosis: rostrum usually as long as carapace, overreaching scaphocerite, ventral margin straight, with six teeth, dorsal margin with eight teeth; antennal spine present; branchiostegal spine present with distinct carina extending twice the length of the spine.
Diagnosis: rostrum directed anterodorsally, large at base tapering to tip, short, reaching a maximum of 3/4 scaphocerite length, dorsal margin slightly concave, with 7-8 teeth at all rostrum length, ventral margin sinuous with or without 0-3 sub-distal teeth; antennal spine present, branchiostegal spine absent, pterygostomian spine present without carina; hepatic groove present; cervical groove well developed; branchiostegal suture not well developed; eyes with cornea weakly developed, more slender than the ocular peduncle; scaphocerite with short distal spine not overreaching blade; stylocerite short, not overreaching the antennular peduncle first segment distal margin (Fig.
amazonicum can be recognized by the long slender rostrum, which reaches distinctly beyond the scaphocerite, the anterior tip directed upwards.
jelskii are: the slender rostrum with the tip curved upwards, reaching beyond the scaphocerite. The dorsal margin bears 6 to 7 (rarely 5 to 8) teeth, excluding the subapical.
The morphological characters of the first postlarva are 43 scaphognathite setae on the maxilla, three scaphocerite spines on the outer margin of antenna, and sternal plate spines: 2,2,0,1,1.
7B): Biramous; protopod two-segmented; endopod and exopod unsegmented; endopod with three naked setae; exopod (scaphocerite) with 12 marginal plumose setae.