Acteonidae, Bullinidae and Ringiculidae (Gastropoda: Heterobranchia) from the Plio-Pleistocene of the Philippines
Author
Helwerda, Renate A.
text
Zootaxa
2015
3990
2
197
220
journal article
10.11646/zootaxa.3990.2.2
1740ec81-c55e-44ce-9a6d-cd62acd5d898
1175-5326
242947
BDF1BC11-4848-4858-99DC-0336A5FBEE2B
Ringicula
spec 3
(
Figure 33
)
Material.
Tiep2 (1)
RGM
961.834.
Characterization.
Shell small; H
2.15 mm
,
W
1.40
mm; protoconch slightly elevated, 1.2 whorl, DP
0.23 mm
; nucleus small, DN
0.10 mm
; teleoconch with distinct subsutural ridge and groove; additional sculpture of 16 spiral grooves on the body whorl; outer lip very thick with swollen lower half; parietal callus with lamella; columella with two folds; lower fold bears two knobs.
Remarks.
This specimen is similar to
Ringicula opima
nov. spec., but its spire is smaller and it has fewer whorls. The thought arose that this specimen is therefore a deviant specimen of this species, with a teratologically small size. However, its apertural callus is well developed, but it does not extend as far onto the base as in
Ringicula opima
nov. spec.. It also bears two knobs on the lower fold of the columella and its outer lip is only slightly projected beyond the columella. The rest of the apertural characters were obscured by sediment, but they were revealed by making a 3D reconstruction of a CT-scan of this shell. This shows that the columellar folds are also shaped differently. All in all, this specimen differs from
Ringicula opima
nov. spec. in so many characters, that it is treated separately here.