Neodexiospira alveolata

About Neodexiospira alveolata

Neodexiospira alveolata is represented on Kauaʻi by the source name Neodexiospira nipponica Okuda, 1934 in Coles and colleagues’ 2004 marine survey report. Appendix A, printed page 91, marks its present-study occurrence at Ka4, rather than at all four Kauaʻi stations. Other marks on that row belong to other islands. This is evidence from the report’s 2002 survey, not a newly confirmed island-wide population or a 2026 observation. The source classified the organism as cryptogenic, meaning its native or introduced origin was uncertain.

Current registry usage accepts N. nipponica as Neodexiospira alveolata (Zachs, 1933). The Atlas preserves the source name as an alias and keeps its historical evidence attached to the accepted display name. It does not substitute a photograph of the superficially similar N. brasiliensis or treat an unidentified Neodexiospira as this species. Microscopic characters remain important: the 1975 revision distinguished Japanese nipponica material using the anterior pegs of the thoracic hooks and the opacity of the brood chamber. A large ecological illustration cannot establish those characters in a Kauaʻi specimen.

Uchida’s 1971 account describes a chalky-white, dextrally coiled tube, approximately 2–2.5 mm across, with three longitudinal ridges and two projections at the opening. The living worm has an orange three-segment thorax without adult eye spots, a long intervening region, and a pale-orange abdomen of about fifteen bristle-bearing segments. Yellowish-brown digestive pigment may be visible. Seven slender pale-orange branchial radioles bear paired fine branches and long bare tips. Their crown collects suspended food and can withdraw into the tube.

The operculum changes during development and reproduction. An immature individual has a primary conical operculum with a short skirt; the breeding form develops a cylindrical chamber beneath its calcareous plate. Uchida described greenish-gray embryos brooded there. These are meaningful structural differences, rather than a male/female color contrast. The plate therefore combines a brooding adult with an immature form, retaining the complete crown, segmented body and posterior of both.

The tubes are represented opened in a continuous submerged hard-substrate setting so the ordinarily concealed bodies remain inspectable. This is a disclosed morphological reconstruction, not an observation of worms naturally living in broken tubes. The Japanese descriptions and drawings supply anatomical context; their collection sites, reproductive timing and abundance are not transferred to Kauaʻi. Re-examination of local vouchers, including tube, operculum and chaetae, would strengthen the link between the historical source identification and the modern species concept.