Galathowenia Kirkegaard, 1959; Fauchald, 1977; Blake, 1984, 2000.
Clymenia Ørsted, 1844 [not Münster (Ammonoidea)].
Psammocollus Grube, 1866.
Emended diagnosis: Head cylindrical, anteriorly truncated, terminal mouth extending midventrally as an elongated slit and with ventral pharyngeal organ. Breakage groove between first and second chaetiger. Oesophageal commissure Y-shaped. First three segments generally uniramous, with capillaries on notopodia. Following segments biramous, notopodia with capillary chaetae only and neuropodial uncini with two teeth generally obliquely arranged.
Type species: Galathowenia africana Kirkegaard, 1959, by original designation.
Remarks: The presence of a breakage groove between the first and second chaetiger has been identified in several species of the genus (Blake, 1984; Parapar, 2001, 2003a), including the type material of the type species (as drawn by Kirkegaard, 1959 and studied by J. P.), as a line of autotomy. Although it has not been described in several other Galathowenia species it could have been overlooked and represents a potential synapomorphy for the genus (Fig. 1B). Other main features characterizing Galathowenia are the presence of a cylindrical head with a truncated anterior end, an attribute shared with Owenia but differing from this genus in lacking a tentacular crown, and the presence of a ventral slit with prominent lateral lips. An exception to this head shape, with the ventral slit not well developed, is G. australis (Grube, 1866), which has been shown here not to belong to this group (Fig. 1C, D), contrary to earlier studies (Parapar, 2003b).