shell & gill
Runcina sp. #2
|Maximum size: 4 mm.
a tiny, oval species with a featureless notum and no obvious
shell. The posterior margin conceals a small folded gill on the right
side and a small plate-like shell on the left side. It has a reddish
background color with both minute brown flecks and larger cream flecks
on its notum.
Natural history: Runcina
sp. #2 is a moderately common species. It may be found
occasionally in shallow, moderately protected rocky habitats at depths of 7 m (23 ft) or less. (Note 1) However, it appears to occur primarily in Halimeda kanaloana beds
at depths of 13 to 29 m (43 to 95 ft).
Taxonomic notes: This species was formerly lumped with Runcina
sp. #1. However, the consistent association of reddish color and
flecks plus it's different habitat suggest that the two forms are likely
to prove distinct species with future work (though, it remains possible that they could be "re-lumped"). It was probably first
recorded in Hawaii from Airport Beach, Maui by PF on Oct. 22, 1994.
Photo: CP: 2 mm: Airport Beach, Maui; July 19, 2005.
Observations and comments:
1: All photographed specimens of Runcina sp. #1 and Runcina
sp. #2 are unambiguously assignable to one or the other based on the
background color and spotting. However, some of our notes regarding
unphotographed animals found in the shallows at Hekili Point, Maui
between 1991 and 1997 are ambiguous with regard to those characters.
This may have been due to using different standards for the
descriptions when we were still lumping them under one species or it may
indicate that Runcina sp. #2 also occasionally occurs in shallow rocky habitats at depths of at little as 1 m (3 ft).