Family Serpulidae Rafinesque, 1815

‘Bexhaven tubes’

(Fig. 3)

Material. BXG, many small-diameter tubes occurring clustered together (Fig. 3A). Collected by C. T. S. Little.

Occurrence. Bexhaven locality, northern Hawke’s Bay area, east coast of North Island, New Zealand (~ 38 º 3 ' S, 178 º 5 ' E). Seep carbonates occurring as isolated lenses in mudstone, Bexhaven Limestone Formation, Tolaga Group, Middle Miocene (Campbell et al. 2008; Saether 2011).

Description. Carbonate tubes 0.5–1.9 mm in diameter, non-branching, somewhat sinuous (wavy) (Fig. 3A), and appearing to have been originally rigid as they demonstrate clean fractures (Fig. 3E). Tubes do not taper in the fragments observed. Tube wall surfaces exhibit numerous fine, parallel transverse wrinkles (Fig. 3B). Tubes are clearly attached to each other (Fig. 3C, D), and show chevron-like multi-layered tube wall structure (Fig. 3E), while in some cases the tube walls have been replaced (Fig. 3D). Tube walls do not appear to contain preserved organic matter (Fig. 25).

Remarks. The attachment exhibited by the tubes and the chevron-like structure of their walls clearly point to the tubes having been made by Serpulidae Rafinesque, 1815, and they are identified as such by both cluster and cladistic analyses (Figs 22, 24). The tube wall ornamentation of fine closely spaced transverse wrinkles is also seen in many members of this family (e.g. Serpula spp.). Serpulids have also tentatively been suggested to occur at the Haunui and Ugly Hill localities (Saether 2011).