Galathowenia

DIAGNOSIS (adapted from Capa et al. 2012). — Cylindrical head, anteriorly truncated, terminal mouth extending mid-ventrally as an elongated slit and presence of ventral pharyngeal organ. Breakage groove between first and second chaetiger. Y-shaped oesophageal commissure. First three segments uniramous, with capillaries on notopodia. Following segments biramous, notopodia with capillary chaetae only and neuropodial uncini with two obliquely arranged teeth.

REMARKS Galathowenia was established by Kirkegaard (1959) for G. africana, the holotype was collected during the “ GALATHEA’ ’ expedition on the west coast of Africa. In addition to being differentiated based on the shape of the prostomium (anteriorly truncated) with a ventral cleft, G. africana species was characterised by having an “ achaetous peristomium fused with the prostomium, the presence of two eye-spots and three thoracic segments without neuropodial hooks ”. The validity of Galathowenia was later agreed upon by several taxonomists because of the shape of the prostomium (Fauchald 1977; Kirkegaard 1983, 1996; Blake 1984, 2000; Imajima & Morita 1987; Parapar 2003 b). Currently, Galathowenia is featured by having a terminal mouth extending mid-ventrally as an elongated slit, the presence of a breakage groove between the first and the second segments, notopodia with only capillary chaetae on both uniramous and biramous segments, and uncini with a teeth of similar size and generally arranged obliquely (Capa et al. 2012). Among all genera, Galathowenia is more similar to Myriochele because of the lack of distal appendages. However, they can also be distinguished by: 1) the truncated and elongated head of Galathowenia; in contrast to the rounded head of Myriochele; 2) the absence of acicular notochaetae in Galathowenia, which are present in Myriochele; and 3) the presence of a breakage groove between segments 1 and 2 in Galathowenia, which is absent in Myriochele. The species discrimination in Galathowenia is based on: 1) the presence / absence of eyes on head structures; 2) the number, relative length, and distribution of the anterior uniramous thoracic chaetigers; 3) the relative length of the first biramous abdominal segment; 4) the position of the longest chaetiger; 5) the shape and dentition of the uncini; and 6) through the posterior end which bears a different number and structure of lobes.

T YPE SPECIES. — Galathowenia africana Kirkegaard, 1959, by original designation.