On the publication date, authorship, and type species of Umbraculum and Tylondina (Gastropoda : Opisthobranchia : Tylodinoidea)

The genus name Umbraculum Schumacher, 1817 is a senior synonym of Umbrella Lamarck, 1819, Gastroplax de Blainville, 1819, Ombrella de Ferussac, 1821, Umbella delle Chiaje, 1831, and Operculatum Morch, 1852. Other names previo usly introduced for this genus are not available in the meaning of the Inte rnational Code of Zoological Nomenclature. Several authors have alternative ly considered Patella sinica Gmelin, 1791, or Patella umbracula Light-foot, 1786, to be the type species of Umbraculum. However, since none of these s pecies was listed in the original description of this genus, they are not e ligible to be the type species. Acardo umbella Lamarck, 1801 [= Umbraculum umbraculum (Lightfoot, 1786)] is here selected to be the type species of Um braculum. In addition, a valid designation of type species for Umbrella, Om brella, and Operculatum could not be found in the literature; Umbrella indi ca Lamarck, 1819, is here selected to be the type species of these genera. Thus, these three names become objective synonyms. The genus name Tylodina Rafinesque, 1814, type species Tylodina punctulata Rafinesque, 1814 [= Tylo dina perversa (Gmelin, 1791)], by monotypy, was published in 1814 and not i n 1819.