TY - JOUR AB - An annelids’ theory of myzostomid origin is reviewed, and a comparative morphological and embryological diagnostic traits of myzostomids are described. The analysis of these traits gives evidence of myzostomid closeness to molluscs and dinophilids than to annelids. Among Trochozoa two new groups of superphylun level are distinguished: First one Trochozoa oligomera include the most primitive trochophore animals – phylum Mollusca, phylum Myzostomida and class Dinophilida that have larval body only. Second group Trochozoa polymera includes phylogenetically more advanced phylum Annelida and phylum Arthropoda with body that have both larval and postlarval segments. There is created new phylum Myzostomida with description of its diagnosis. The differential diagnosis for each order and families of myzostomids are described. A1 - Wagin, V.L. (Vladimir Lvovich) JO - Uchenye Zapiski Kazanskogo Universiteta. Seriya Estestvennye Nauki N1 - World Polychaeta Database (WPolyDb). Note that this article was posthumous, published in memoriam. Wagin (1907-1984) had died in 1984. C1 - 149 (3): 31–41. (In Russian) TI - On the annelid theory about the origin of myzostomids, their position in the system of Trochozoa, and identification of the new phylum Myzostomida. UR - https://elibrary.ru/item.asp?id=11137617 PY - 2007 Y2 - 2024-03-28 ER -