New Monocotylidae (Monogenea), branchial parasites of Dasyatis pastinaca (L) (Euselachii, Dasyatidae) - Complements to a description of Heterocotyle pastinacae Scott, 1904

Heterocotyle scotti n. sp. and H. similis n. sp., two gill parasites of Das yatis pastinaca, are described. H. pastinacae Scott, 1904, is redescribed f rom the gills of the same Mediterranean host species. New features concerni ng haptor morphology are reported. The disposition of the sinuous ridges on the haptor of these three species is discussed. All three species possess a spermatophore. The variation in vaginal anatomy of H. pastinacae leads to the suggestion of a sequence explaining the development or destruction of the spermatophore. The specificity of these parasites and their relationshi ps with Heterocotyle from the Atlantic coast of America are discussed.