Tornatella siebaldii, Helwerda, Renate A., 2015

Helwerda, Renate A., 2015, Acteonidae, Bullinidae and Ringiculidae (Gastropoda: Heterobranchia) from the Plio-Pleistocene of the Philippines, Zootaxa 3990 (2), pp. 197-220 : 198-201

Japonacteon sieboldii ( Reeve, 1842)

( Figure 1–3 )

1842 Tornatella siebaldii n. sp. —Reeve: p. 61.

2000 Acteon siebaldi ( Reeve, 1842) —Hori: p. 733, pl. 365, fig. 1. 2008 Japonacteon sieboldii ( Reeve, 1842) —Valdés: p. 601–604, figs. 6A–D, 7, 8A.

Material. Anda1 (2) RGM 961.760, Anda2 (fragments) RGM 961.761, Anda3 (2) RGM 961.762, Anda4 (5) RGM 961.763, AndaDeVos (2) RGM 961.764, Roxas (2) RGM 961.765, Tiep2 (1) RGM 961.766, Tiep5 (1) RGM 961.767.

Characterization. Shell tall; H 5.95 mm, W 2.90 mm; protoconch inclined, 1.1 whorl, DP 0.51–0.54 mm; nucleus small, DN 0.21 mm; teleoconch sculpted with punctuated spiral grooves with oval punctuations; strong spiral groove with elongated punctuations below suture; space between grooves increases along the whorl, additional grooves intercalate; aperture narrowly semicircular; columella with weak single fold; umbilicus very narrow to closed.

Distribution. Japan and South China Sea, sand bottom, in 10–30 m ( Hori, 2000). Fiji, Indonesia, New Caledonia, Tonga, Vanuatu and Wallis Island, in 182–555 m, live in 440–487 m ( Valdés, 2008).

Remarks. According to Valdés (2008), this species might represent a species complex, because of its variability in shell morphology and broad geographic and bathymetric range. Valdés (2008) further mentions that all specimens share a closed umbilicus, yet we also encountered specimens with a very narrowly open or rimate umbilicus.

Figures

FIGURE 1 – 7. 1. Japonacteon sieboldii (Reeve, 1842). RGM 961.831. Locality Anda 4. (a) rear view, (b) apertural view, (c) basal view, (d) apical view. For these and remaining figures, all material derives from the Piazencian or Gelasian of the Santa Cruz Formation of Cabarruyan Island or nearby Luzon Island, Philippines. Scale bars = 1 mm. 2. Japonacteon sieboldii (Reeve, 1842). RGM 961.830. Locality Roxas. (a) apertural view. 3. Japonacteon sieboldii (Reeve, 1842). RGM 961.739. Locality Anda 4. (a) apertural view, (b) apical view. 4. Bathyacteon valdesi nov. spec .. Paratype RGM 961.746. Locality AndaDeVos. (a) apertural view, (b) apical view. 5. Bathyacteon valdesi nov. spec .. Holotype RGM 961.786. Locality AndaDeVos. (a) rear view, (b) apertural view, (c) basal view, (d) apical view. 6. Acteon spec 1. RGM 961.768. Locality Anda 4. (a) rear view, (b) apertural view, (c) basal view, (d) apical view. 7. Acteon spec 1. RGM 961.741. Locality Anda 4. (a) apertural view, (b) apical view.