Lysidice unicornis

About Lysidice unicornis

Lysidice unicornis is retained from the Bishop Museum’s 2004 harbor and nearby reef census. Appendix A, printed page 85, reports Nematonereis unicornis Schmarda, 1861 in all four Kauaʻi present-study columns, Ka1–Ka4; the 1996 DeFelice compilation also marks Ka1 and Ka3. These are source-bounded occurrence statements. They do not establish current abundance, population trend or an island-wide present distribution.

The source authorship is preserved rather than silently discarded. The World Polychaeta Database treats both Nematonereis unicornis Schmarda, 1861 and the Grube combination as synonyms of Lysidice unicornis (Grube, 1840). This reconciles the reported name with the Atlas display name without creating a second species or a new observation. The 2021 Eunicida review nevertheless flags the historically broad unicornis distribution as requiring further scrutiny; nomenclatural agreement is not a new diagnostic examination of the Kauaʻi voucher.

Published treatments describe a very slender worm, with a rounded anterior prostomium, a single occipital antenna and a conspicuous eye pair. Two apodous peristomial rings precede the chaetigers. Its low uniramous parapodia carry dorsal and ventral cirri and several microscopic chaetal types, including capillaries, comb chaetae, compound falcigers and subacicular hooks. Fauvel’s 1953 account gives pink iridescence, orange anterior coloration and a greenish posterior in its material. Schmarda’s original account describes a pale red worm with a reddish-brown rear. These accounts supply morphology references, not measurements of Kauaʻi color or body size.

Miura’s 1979 Japanese treatment illustrates the head, parapodia and jaws but explicitly describes two incomplete specimens. The retrieved sources do not resolve a complete species-specific terminal structure well enough to add unseen appendages or a tail copied from another eunicid. The former image is therefore retained as a secondary reference while the primary remains unavailable. This is an evidence gap, not a deletion of the local record.

Gambi and Cigliano’s Mediterranean study documents separate sexes without external sexual dimorphism, with enlarged eyes and a fragile swollen posterior in mature unicornis material. The photographed reproductive female has a partially detached rear. Neither that image nor a fragment is substituted for a complete primary, and its spawning timing is not transferred to Kauaʻi. A complete local voucher or a well-resolved named-species posterior reference, followed by comparison of jaws and chaetae, would allow a scientifically defensible whole-animal plate. Local diet and breeding ecology remain unmeasured by this census entry.