Siphopteron sp. 1 (ca. 3mm)

Opisthobranch of the Week Data


Frequency on Okinawa: Collection Data:
[brackets indicate range for all Okinawa-collected specimens of the species]

Species Account:

        Siphopteron sp. 1 is considered to be very rare in the waters of Okinawa's main island as I have seen and collected only the single above featured animal. It was found as a collaterally-collected specimen shortly following a SCUBA excursion. Later at home while observing material in a sorting bowl, originally composed of a zip-loc bag of misc. cnidaria, algae, coral rubble and sand, this tiny gastropterid was found swimming about by actively flapping its parapodia. This behavior was noted again moments later in a small glass photo tank.

        Rudman (1999) commenting in the Sea Slug Forum feels that this animal should perhaps be considered a species of Gastropteron as there is no indication of the siphonal crest characteristic of the genus Siphopteron. Ono (2004) illustrates several similar 3mm & 4mm animals in his recent book* (as Gastropteron spp. 1 & 2, pp. 24-25). Until the taxonomy is confirmed I'll leave the animal as an unknown species of Siphopteron.

* This beautifully illustrated book is available from:


Literature Cited:

Page Date: 26 July '04
Page Modification Date: 26 Jul '04
Digitally manipulated photo
Copyright © 2004 Robert F. Bolland