Saisonale und morphogeographische Differenzierung bei Leptomysis lingvura und zwei verwandten Spezies (Crustacea, Mysidacea)

The seasonal and morphogeographic differentiation of populations of Leptomysis lingvura (Sars), L. heterophila n. sp., and L. posidoniae n. sp. is studied in detail. Main diagnostic features are scales at the outer ventral margin of the mandibula in L. heterophila n. sp., the eyestalks completely covered with scales in L. posidoniae n. sp., and the lack of both features together with large size of body chromatophores in L. lingvura (Sars). The latter species occurs in three morphologically distinct forms: at Atlantic coasts L. lingvura lingvura (Sars) with the exopod of fourth pleopod of males 10 to 11-segmented; in the central and west Mediterranean and in the Aegean Sea the revalidated L. lingvura marioni (Gourret) having this pleopod 8 to 9-segmented and the first thoracic epipod with a large seta; and in the Adriatic and the Ionian Sea L. lingvura adriatica n. ssp. without this seta. Adriatic populations of L. lingvura and L. heterophila each show morphologically different over-wintering and summer generations. These differences are weaker or do not exist in west or in central Mediterranean populations, respectively.