Echinoderes sp.

Grzelak, Katarzyna & Sørensen, Martin V., 2022, Echinoderes (Kinorhyncha: Cyclorhagida) from the Hikurangi Margin, New Zealand, European Journal of Taxonomy 844, pp. 1-108 : 81-82

Echinoderes sp. aff. E. galadrielae / E. beringiensis

Fig. 32 ; Table 20

Material examined

NEW ZEALAND • 1 ♀; Hikurangi Slope , stn TAN1004/4; 41.6837° S, 175.6642° E; 1046 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NIWA-159427 . Mounted for LM in Fluoromount G on glass slide • 2 ♂♂; Hikurangi Slope , stn TAN1004/38; 41.5937° S, 175.8532° E; 1121 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; personal reference collection of MVS. Mounted for SEM • 1 ♀; Hikurangi Slope , stn TAN1004/76; 41.6833° S, 175.6500° E; 1282 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NHMD-921503 . Mounted for LM in Fluoromount G on HS slide • 1 ♂; same collection data as for preceding; personal reference collection of MVS. Mounted for SEM • 1 ♀, 1 ♂; Pahaua Canyon , stn TAN1004/12; 41.5508° S, 175.7250° E; 1350 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NHMD-921498 to 921499. Mounted for LM in Fluoromount G on glass slides • 2 ♂♂; Pahaua Canyon , stn TAN1004/27; 41.4983° S, 175.7043° E; 1013 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; personal reference collection of MVS. Mounted for SEM • 1 ♂; Honeycomb Canyon , stn TAN1004/53; 41.4563° S, 175.8970° E; 948 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NHMD-921500 . Mounted for LM in Fluoromount G on glass slide • 1 ♂; Honeycomb Canyon , stn TAN1004/58; 41.4080° S, 175.8977° E; 1171 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NHMD-921502 . Mounted for LM in Fluoromount G on HS slide • 1 ♀; Seamount 310, stn TAN1004/69; 41.3353° S, 176.1882° E; 670 m b.s.l.; Apr. 2010; NIWA TAN1004 Voyage; soft sediment; NHMD-921501 . Mounted for LM in Fluoromount G on glass slide .

Distribution

Hikurangi Margin, from slope, through canyon, and seamount habitats, 670–1350 m b.s.l. See Fig. 1 for a geographic overview of stations and Table 1 for station and specimen information.

Brief description and remarks

The examined specimens closely follow the morphology of E. galadrielae sp. nov. in terms of distribution of spines, tubes, glandular cell outlets, and even the middorsal division of the tergal plate of segment 11. However, E. galadrielae and E. aff. E. galadrielae / E. beringiensis differ at two important points, i.e., spine morphometrics (see Table 20) and the shape of the tergal extensions (compare Figs 30A , 31D, I with Fig. 32 ). Middorsal spines were in general longer in this current set of specimens, while the lateroventral ones were shorter than in E. galadrielae . The unidentified specimens have also markedly longer lateral terminal spines, which in most cases exceed the trunk length, resulting in markedly higher LTS/TL ratio in this species compared to E. galadrielae (average LTS/TL: 106% vs 87%, respectively). The most conspicuous difference between E. galadrielae and these unidentified specimens is expressed in the tergal extensions, which are exceptionally long in E. galadrielae ( Figs 29–31 ). This stands in strong contrast to the short, triangular tergal extensions in the unidentified specimens ( Fig. 32 ). These tergal extensions are much more similar to those in E. beringiensis as well as many other species of Echinoderes .

We would, on the other hand, hesitate in identifying the specimens as E. beringiensis , since they differ in the distribution of sensory spots and lack the midlateral glandular cell outlets type 2 that characterizes females of E. beringiensis (see Adrianov & Maiorova 2022). In addition, E. beringiensis has a longer trunk (TL: 331 µm vs 208 µm, respectively) and has proportionally shorter lateral terminal spines (LTS/TL: 50% vs 106%, respectively). In conclusion, these enigmatic specimens appear to represent an intermediate between E. galadrielae sp. nov. and E. beringiensis , and it would require a molecular comparison to unveil their true identity.

Figures

Fig. 32. Segment 11 and morphological variations of tergal extensions in Echinoderes sp. aff. E. galadrielae/E. beringiensis. A–C. Light micrographs. D–F. Scanning electron micrographs.

Fig. 1. Map showing the sampling stations. Colour codes indicate slopes (red), canyons (green), and seamounts (yellow). Inset shows New Zealand with a frame marking the sampling area.

Fig. 30. Light micrographs showing overview and details of Echinoderes galadrielae sp. nov. A. ♀, paratype (NHMD-921497). B–C. ♀, holotype (NIWA-159425). D. ♀, paratype (NHMD-921496). E. ♀, paratype (NIWA-159426). A. Ventral overview, with inset showing close-up of segment 11. B. Segments 1 to 5, dorsal view. C. Segments 1 to 7, ventral view. D. Segments 6 to 8, lateral view. E. Segments 8 to 11, lateral view. Abbreviations: see Material and methods.

Fig. 31. Scanning electron micrographs showing overviews and details of Echinoderes galadrielae sp. nov.A. Ventral overview.B. Segments 1 to 5, dorsolateral view.C. Segments 1 to 2, lateroventral view. D. Dorsal overview. E. Segments 5 to 7, ventral view. F. Segments 4 to 7, lateral view. G. Segments 8 to 10, dorsolateral view. H. Segments 10 to 11 of male, dorsolateral view. I. Segments 10 to 11 of female, dorsal view with insets showing close-up of reduced laterodorsal tubes on segment 10. Abbreviations: see Material and methods.

Fig. 29. Line art illustrations of Echinoderes galadrielae sp. nov. A. ♀, dorsal view. B. ♀, ventral view. C. ♂, segments 10–11, dorsal view. D. ♂, segments 10–11, ventral view. Abbreviations: see Material and methods.