Comparative morphology of the foregut of four Gnathophausia species (Crustacea; Mysidacea; Lophogastrida). Relationships with other taxa

Abstract

The features of the foregut of Gnathophausia ingens Dohrn, 1870, G. zoea W.-Suhm, 1875, G. longispina G. O. Sars, 1883 and G. gracilis W.-Suhm, 1875 (Crustacea, Mysidacea, Lophogastrida, Lophogastridae) are described, based on scanning electron microscopy. Comparisons are made with the foregut of related taxa, particularly with Eucopia, the only genus constituting the second family (Eucopiidae) of the Lophogastrida. The foreguts of Gnathophausia and Eucopia exhibit (1) common features, which might be characteristic of the sub-order Lophogastrida, (2) more similarities with those of the Decapoda than those of the sub-order Mysida. But preliminary observations suggest that the stomach is obviously smaller than that of the similarly sized Decapoda. The foregut of Gnathophausia is morphologically unique to this genus, although each species exhibits small specific differences.

Keywords :

• Foregut
• morphology
• Crustacea
• Mysidacea
• Lophogastrida
• Gnathophausia