Galathowenia quelis, Capa & Parapar & Hutchings, 2012

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 : 246-248

GALATHOWENIA QUELIS SP. NOV.

FIGURES 2E–H , 4 , TABLES 1, 2

Holotype: New South Wales, Pittwater, AM W37821, west of Sand Point , 33°35′44″S, 151°18′20″E, sandy mud, 15.6 m, 2.xii.2004.

Paratypes: New South Wales, Pittwater, AM W37822, same sample (six specs); Botany Bay , AM W37823, east end of runway 34 R, 33°58′33″S, 151°11′42″E, sandy mud, 16.5 m, 15.ix.2004 (eight specs) , AM W37824, 800– 1000 m off Port Botany, 33°58′45″S, 151°11′1″E, 7 m, 28.vii.1992 (one spec.), AM W37825, 800– 1000 m off Port Botany , 33°58′45″S, 151°11′1″E, 7 m, 28.vii.1992 (one spec.), AM W37826, 33°58′16″S, 151°11′58″E, 7 m, 27.vii.1992 (one spec.) .

Other material examined (Appendix 1): New South Wales (256 specs): Botany Bay, Malabar, Port Jackson, Pittwater; Queensland (12 specs): Shoalwater Bay; Northern Territory (two specs): Arafura Sea.

Description of holotype: Slender, thread-like body, measuring 13.0 mm long, 0.15 mm wide, with 20 chaetigers; cylindrical in cross section ( Figs 2E–G , 4A–C ). Head elongated, cylindrical, of same width as anterior segments; anterior end truncated, with terminal ciliated mouth opening ( Figs 2E, F , 4A, B, D, E ), extending midventrally as an elongated slit. Head smooth, with no folds or grooves, continuing to first segment with no apparent external division, with a pair of ventrolateral brownish eyespots. Anterior region with three short uniramous segments, each with notochaetae only. Second segment twice as long as first and third; RLUS = 1:2:1 ( Figs 2E, F , 4B, C ). Deep groove encircling the body, between first and second chaetiger, except for a short dorsal portion ( Fig. 4A–C ). Oesophageal commissures with Y shape in anterior segments. Biramous chaetigers six to ten times longer than wide, becoming shorter and compact in last three posterior segments; chaetiger 6 longest. Notochaetae of all segments similar, capillaries, decreasing in length ventrally within each fascicle, with proximal part smooth or slightly striated and mid and distal end with sculpture resembling scales ( Fig. 4F, G ). Acicular chaetae absent. Posterior chaetigers with fewer but longer chaetae than anterior segments ( Fig. 4 K, L ). Neurochaetae, as uncini, present from chaetiger 4 in long and broad lateroventral tori, decreasing posteriorly in size and number of uncini. Anterior uncinal fields with around six to eight transverse rows of uncini ( Fig. 4H ); tori of posterior part much shorter. Each uncinus bifid, provided with two nearly equally convex teeth, one offset slightly higher than the other and arranged in an oblique row ( Fig. 4I, J ). Anus terminal surrounded by a ciliated rim ( Fig. 4 K–M ), with two low blunted lobes on each side ( Fig. 2G ). Tube three to four times longer than animal, with thin secreted layer encrusted with sand grains ( Fig. 2H ). Colour in alcohol pale yellow, with no pigment pattern ( Fig. 2E–G ).

Variation: The specimens examined vary between 15 to 20 segments and 6–16 mm in length. Some paratypes and additional material show the anterior end weakly rounded instead of truncated. Eyespots have faded in some specimens, probably related to the time of storage in alcohol. Shape of pygidium varies slightly amongst specimens and probably as a result of methods of fixation and/or manipulation for observation; specimens studied under the dissecting microscope showed a well-marked bilobed pygidium ( Fig. 2G ) whereas in specimens observed under SEM, the pygidium resembled a short rim with a slightly enlarged dorsal border ( Fig. 4 K–M ). We believe that this difference may be because of the critical point drying method. Some specimens are slightly brownish after preservation but none of the material examined exhibited any distinguishable colour pattern.

Ecological notes: This species has been found mostly in estuaries and sheltered bays in muddy and sandy sediments between 1 and 60 m in depth, but some specimens were also found in deeper exposed environments along the temperate and tropical coast of eastern Australia ( Fig. 14 ). Galathowenia quelis sp. nov. cohabits with G. annae sp. nov. in some New South Wales estuaries. The holotype and other specimens were found with one parasitic copepod living inside the tube and attached to the worm body by its anterior end.

Etymology: This species is dedicated to Ángeles Iglesias-Díaz (nickname Quelis), who was supportive of the project.

Remarks: Galathowenia quelis sp. nov. could be another example of a species belonging to what we have named the G. oculata complex, as it shares with this species the general combination of features mentioned above. However, G. quelis sp. nov. differs from previous descriptions of G. oculata in some features (see Table 2). The RLUS (= 1:2:1), differs from the European, west Greenland, and Californian specimens (1:1:1, Nilsen & Holthe, 1985; as per Blake & Dean, 1973 and Blake, 2000: fig. 5.1a) and those from Japan (1:1:0.5, Imajima & Morita, 1987). Galathowenia haplosoma ( Gibbs, 1972) was described from the Cook Islands as a Myriochele species. Owing to the shape of the head and the lacking references to the acicular chaetae, we consider that it should be moved to Galathowenia . Members of this species are small (4.0 to 7.5 mm length) and share with G. quelis sp. nov. the presence of eyes and a pygidium divided by a small cleft ( Gibbs, 1972: fig. 8a–c), but differ in the relative length of uniramous segments (1:1:0.5 in G. haplosoma vs. 1:2: 1 in G. quelis sp. nov.).

Galathowenia quelis sp. nov. also resembles G. annae sp. nov. described above, as both have anterolateral eyespots, a groove between the first and second segments, a similar number and relative length of anterior segments (RLUS), and the same type of sediment attached to the tube. Moreover, these two species are sympatric in New South Wales (even being found in the same samples). However, they are easily distinguished by conspicuous pigmentation on the head (an attribute of G. annae sp. nov.) and by the pygidium (as a low rim or bilobed in G. quelis sp. nov. against three digitiform lobes in G. annae sp. nov.).

Figures

Figure 2. A–D, Galathowenia annae sp. nov. Paratype, AM W37233. A, anterior end, ventrolateral view. B, anterior end, lateral view. C, posterior end, ventral view. D, tube. E–H, Galathowenia quelis sp. nov. AM W37821-37822. E, anterior end, ventral view. F, anterior end, dorsal view. G, posterior end, ventral view. H, tube. Abbreviations: b1, biramous segment; g1-2, groove between segment 1 and 2; u1-u3, uniramous segments 1 to 3. Scale bars: A–D = 50 Mm; E–H = 75 Mm.

Figure 4. Galathowenia quelis sp. nov. A, anterior end, ventral view. B, anterior end, ventrolateral view. C, anterior end, dorsal view. D, detail of small spheres (diatoms?) located between the buccal ciliature. E, mouth and ventral slit, ventral view. F, anterior capillary chaetae, proximal end. G, detail of scale covering in capillary chaetae, segment 3. H, neuropodial uncinal field, segment 4 (first biramous chaetiger). I, uncini, same segment, top view. J, uncini, same segment, side view. K, posterior end, ventral view. L, posterior end, lateral view. M, anus, posterior view. Abbreviations: b1, biramous segment 1; g1-2, groove between segment 1 and 2; u1-u3, uniramous segments 1 to 3. Registration numbers: A, AM W37195; B–D, F–J, W37191; E, AM W37192; K–M, AM W37193. Scale bars: A–C = 100 Mm; D, G, I, J = 2 Mm; E, H, K–M = 10 Mm; F = 4 Mm.

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