Sacoproteus cf. smaragdinus (Baba, 1949)
|Maximum size: about 40 mm.
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.
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)
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:
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
Note 2: It's distribution outside of Hawaii will depend on the results of further work.