<p>Notes:</p><table style="width: 479px;" border="0" cellspacing="0" cellpadding="0"><tbody><tr height="17"><td class="xl66" width="479" height="17">Primno macropa and P. latreillei differ in: 1) size- P. macropa reaches 21 mm; 2) sequence of smaller and larger denticles on the 5th segment of pereopods V; and 3) geographic distribution- P. latreillei inhabits tropical and subtropical waters while P. macropa replaces it in temperate and subpolar regions. The remaining differences are less significant. In such a situation it would appear that P. macropa and P. latreillei are cold- and warm-water subspecies of the same species. In the cold-water regions the period of maturation of the crustaceans could be protracted and before achieving full maturity, they might undergo several more molts to reach much larger sizes (the number of segments in the rami of pleopods in the illustration of P. macropa by Bowman is more than in P. latreillei, which confirms the greater number of molts which the former species passed). Further, with an increase in number of molts, additional denticles could appear in the basal part of the subchela of pereopods V. Generally, ornamentation with denticles, spines, and setae in hyperiids is subject to wide variation. The applies also to the ornamentation of the posterior margin of the 6th segment of pereopods VI with small setae; this is "very distinctly" seen in P. macropa while in P. lattreillei this margin is "distinctly smooth, the smallest setae seen only under high magnification" (Bowman, 1978). Naturally, in smaller crustaceans all the structural details appear coarser than in smaller ones. The absence of sympatry in the distribution of the above two species also does not preclude the suggestion of the possible subspecific nature of their differences. The ultimate resolution of the status of P. macropa and P. latreillei requires investigations of the character and range of variation of the morphological features in the genus Primno. In the present key we include P. latreillei in the same form as was described by Bowman. </td></tr></tbody></table>
Sumber: Pelagic Invertebrates