Galathowenia undetermined

Capa, Maria, Parapar, Julio & Hutchings, Pat, 2012, Phylogeny of Oweniidae (Polychaeta) based on morphological data and taxonomic revision of Australian fauna, Zoological Journal of the Linnean Society 166 (2), pp. 236-278 : 252

GALATHOWENIA SP.

FIGURE 6I–P, TABLES 1,2

Material examined (Appendix 1): Queensland, Halifax Bay, north of Townsville , around 19°10′S, 146°37′E (44 specs from seven samples) .

Description: Thin and fragile specimens, most broken and incomplete. Body cylindrical ( Fig. 6I–K ), around 7 mm long, 0.1 mm wide, with 18 chaetigers. Head elongated, truncated anteriorly, with terminal ciliated mouth extending midventrally as an elongated slit ( Fig. 6J ). A pair of ventrolateral brownish eyespots in prostomium. Two transverse grooves present, between head and first segment and first and second segments ( Fig. 6J, K ). Anterior three segments uniramous, each with notochaetae only. Second segment twice the length of first and third (RLUS = 1:2:1). Oesophageal commissures as white ventral longitudinal band with Y shape in anterior segments. First biramous segment similar in length to uniramous ( Fig. 6I–K ). Second biramous chaetiger (segment 5) longest, around eight times longer than wide. Only capillary notochaetae observed, with proximal third smooth and distal end ornamented with scales, with few chaetae in each fascicle ( Fig. 6J, K ). Neurochaetae present from chaetiger 4 in long and narrow ventral tori ( Fig. 6L–N ). Uncini arranged in five to seven transverse rows; each uncinus provided with two nearly equal curved teeth, slightly obliquely arranged, almost vertical and almost fused to each other ( Fig. 6O, P ). Anterior biramous segments with a lateral flap behind chaetae ( Fig. 6M, N ), connected ventrally by a ventral groove ( Fig. 6L ). Pygidium as a rim around anus, appearing as two low lobes under dissection microscope. Tube with thin secreted layer encrusted with small sand particles. Colour in alcohol brownish or pale yellow.

Ecological notes: Species only found in Halifax Bay ( Fig. 14 ), in soft bottoms.

Remarks: Most specimens examined are small, incomplete, or damaged. Some of the relevant diagnostic features, like the presence of the parapodial flaps in the anterior biramous segments have been verified only in two specimens under SEM and are not seen under optical microscopy. The designation of these specimens to an already-described species or their description as a new one is not possible with the limited data available and the poor condition of the material.

Figures

Figure 6. A–H, Galathowenia arafurensis sp. nov. A, anterior segments, lateral view. B, anterior end, ventral view. C, anterior end, lateral view. D, anterior end, dorsal view. E, mouth. F, anterior capillary chaetae. G, neuropodial uncini field, segment 5. H, uncini, same segment, oblique view. I–P, Galathowenia sp. I, anterior segments, dorsal view. J, anterior end, ventral view. K, anterior end, dorsal view. L, detail of groove between segment 1 and 2, ventral view. M, detail of lateral flap, segment 5. N, detail of lateral flap, segment 6. O, neuropodial uncinal field, segment 6. P, uncini, segment 6, oblique view. Abbreviations: b1-b3, biramous segment 1 to 3; gh-1, groove between head and segment 1; g1-2, groove between segment 1 and 2; u1-u3, uniramous segments 1 to 3; vph, ventral pharyngeal organ. Registration numbers: A–H, AM W34017: I–P, AM W37065. Scale bars: A = 200 Mm, B–E = 100 Mm; F, G, N = 10 Mm; H = 2 Mm; I, K = 100 Mm, J, L, M = 20 Mm; O = 2 Mm; P = 1 Mm.

Figure 14. Distribution of Australian oweniids except for members of genus Owenia.