Species list
Next species
Additional Photos 

2nd view

2nd animal





egg mass

Sacoproteus cf. smaragdinus (Baba, 1949)
Sacoproteus cf. smaragdinus
Maximum size:  about 40 mm.

Identification:  This is a relatively large species with weak tubercles on the inner surfaces of its cerata and short white tips on its rhinophores. It is similar to Sacoproteus sp. #1 but has more numerous cerata that are spherical laterally and moderately elongate centrally. The cerata are truncated apically with small central tips. The green line on the top of its head may be complete or incomplete. A faint dusting of white flecks on the sides of the head may be present or absent.

Natural history:  Sacoproteus cf. smaragdinus is known from only a few animals. The first Kauai animal was found at about 1 m (3 ft) at a protected site. (Note 1) Later, about four juveniles were found at less than 2.5 m (8 ft) at a moderately exposed site. The Big Island animals were found in an Ocean Era sea tank on Caulpera lentillifera on which it, presumably, feeds. It lays a white egg mass in an irregular spiral composed of an irregularly flattened ribbon.

Distribution:  Big Island and Kauai: may be more widespread in the Pacific. (Note 2)

Taxonomic notes:  It was first recorded in Hawaii from Anini Beach, Kauai by Cassidy Grattan on Feb. 16, 2018. These animals seem closest to Sacoproteus smaragdinus as illustrated in Krug, et. al. (2018) with the dusting of white flecks on the head of the Kauai animal corresponding to the white line of that species. However, the central cerata seem somewhat more elongate and cylindrical than in his illustrations while the second animal lacks the white flecks on its head. So, the ID needs confirmation with more material and DNA. There's also some chance that the Hawaiian animals might represent more than one species.

Photo:  Cassidy Grattan: 15-20 mm; dusted with sediment; some central cerata autotomized: Anini Beach, Kauai; Feb. 16, 2018.

Observations and comments:

Note 1:  Cassidy Grattan reported that his animal was found at night in a resting posture similar to the resting posture of Ercolania cf. coerulea. He also said it autotomized some of its central cerata while being handled.

Note 2:  It's distribution outside of Hawaii will depend on the results of further work.
Species list
Family Next species Top