Annelida Lamarck, 1809

Georgieva, Magdalena N., Little, Crispin T. S., Watson, Jonathan S., Sephton, Mark A., Ball, Alexander D. & Glover, Adrian G., 2019, Identification of fossil worm tubes from Phanerozoic hydrothermal vents and cold seeps, Journal of Systematic Palaeontology 17 (4), pp. 287-329 : 291

publication ID	https://doi.org/ 10.1080/14772019.2017.1412362
DOI	https://doi.org/10.5281/zenodo.10912357
persistent identifier	https://treatment.plazi.org/id/03C0814B-9039-FFBE-3F6E-FC064A42FB96
treatment provided by	Felipe
scientific name	Annelida Lamarck, 1809
status

Treatment

Phylum Annelida Lamarck, 1809 View in CoL View at ENA

Family incertae sedis

‘Rocky Knob tubes’

( Fig. 1 View Figure 1 )

2008 worm tubes Campbell, Francis, Collins, Gregory, Nelson, Greinert, & Aharon: 90, fig. 4b, c.

2010 worm tubes Saether, Little, & Campbell: 510, fig. 3c.

2011? Siboglinidae Saether : 73, fig. 5.1e–i.

Material. RK-5, block of many large-diameter tubes, mostly in the same orientation. RK-15B-6, block of small-diameter tubes mostly in the same orientation. RNT1, many similar-sized tubes, mostly in the same orientation. RNT2, dense aggregation of small-diameter tubes in a range of orientations. 12-RK, small and larger diameter tubes, mostly in the same orientation. Donated by K. A. Campbell and collected by C. T. S. Little.

Occurrence. Rocky Knob, northern Hawke’s Bay area, east coast of North Island, New Zealand (~ 38 º 19’S, 177 º 56’E). Seep carbonates occurring as isolated lenses in mudstone, Bexhaven Limestone Formation, Tolaga Group, Middle Miocene ( Campbell et al. 2008; Saether et al. 2010; Saether 2011).

Description. Carbonate tubes mostly straight and exhibiting a wide range of diameters, from 1.0 to 7.9 mm, preserved in clusters mostly of similar-sized tubes ( Fig. 1A, B View Figure 1 ). In some clusters, tubes are preserved in the same orientation ( Fig. 1B View Figure 1 ). The tubes are non-branching, large-diameter fragments taper somewhat ( Fig. 1A View Figure 1 ), and some tube walls appear to be touching others ( Fig. 1B, F View Figure 1 ). Tube walls are mostly smooth ( Fig. 1C View Figure 1 ); however, one tube exhibits small round textures on its surface ( Fig. 1D View Figure 1 ) while another small-diameter tube bears fine, long, continuous longitudinal wrinkles ( Fig. 1B View Figure 1 ). Tube walls appear to have been originally fibrous as in places torn fibres are preserved ( Fig. 1E View Figure 1 ), and some of the tubes also seem to have been originally flexible due to the occurrence of irregular tube cross-sections ( Fig. 1F View Figure 1 ). The tubes show pronounced organic content ( Fig. 1G View Figure 1 ; Supplementary File 1, Table S9). The tubes also appear originally to have been multi-layered ( Fig. 1E, G, H View Figure 1 ), with delamination occurring between some layers ( Fig. 1H View Figure 1 ). Some tube sections show well-consolidated lamination that is many layers thick ( Fig. 1G, H View Figure 1 ).

Remarks. Tubes from Rocky Knob have previously been tentatively ascribed to siboglinids ( Saether 2011). However, cluster and cladistic analyses ( Figs 22 View Figure 22 , 24 View Figure 24 ) failed to place these tubes among the siboglinids or any other annelid families included in the analyses. Noting their similarity to vestimentiferan tubes, we therefore assign these tubes to the annelids only, as more information would be required to assign them to siboglinids. The abundance of these tubes at this ancient seep, large diameter range, generally smooth organic tube walls, and the thick, neatly multi-layered tube wall appearance in some of the specimens do suggest a vestimentiferan affinity. The round structures ( Fig. 1D View Figure 1 ) present on the surface of a large-diameter tube may constitute the circular bases of aragonite botryoids ( Fig. 1F View Figure 1 ).