Volvulella aff. minoensis Itoigawa, 1958

Kiel, Steffen, Fernando, Allan Gil S., Magtoto, Clarence Y. & Kase, Tomoki, 2022, Mollusks from Miocene hydrocarbon-seep deposits in the Ilocos-Central Luzon Basin, Luzon Island, Philippines, Acta Palaeontologica Polonica 67 (4), pp. 917-947 : 941

Volvulella aff. minoensis Itoigawa, 1958

Fig. 20N .

Material.— One specimen from block I ( NRM Mo 192641: H = 12.8 mm, W = 7.4 mm). Upper Miocene of the “shale quarry” within the Northern Cement Corporation quarry in Pangasinan province, Luzon, Philippines .

Remarks.—The pointed apex characteristic for Volvulella is eroded away in the only available specimen, but its former presence is indicated by the blunt apical peg and the apically broken aperture. The type specimens of V. minoensis illustrated by Itoigawa (1958: 178, pl. 26: 8, 9) from the Middle Miocene Mizunami Group in south-central Honshu, are reported to have fine incisions at both ends; these, too, may have been eroded away in NRM Mo 192641. The other Miocene Japanese Volvulella species reported by Itoigawa (1958) are more slender than V. minoensis .

Similar in shape, size and having a smooth shell is the extant Volvulella ovulina (Adams in Sowerby, 1850) which occurs in 10–477 m depth, from Japan to southeastern Indonesia ( Valdés 2008). Slightly more globular and with fine incisions near the base is Volvulella volvulaeformis ( Seguenza, 1879) from the Italian Pliocene ( Brunetti 2020), whereas the Early Miocene V. staphylemorpha Harzhauser, 2014 , from shallow-marine deposits in Kerala, SW India, has a more slender shell ( Harzhauser 2014).

Figures

Fig.20.Caenogastropoda and Opisthobranchia from Upper Miocene seep deposits of theAmlang Formation in Pangasinan province, Luzon, Philippines. A. Naticidae gen. et sp. indet., NRM Mo 192628, imperfect specimen in apical and apertural views. B, C. Very large Fusinus? sp., imperfect specimens in abapertural view. B. NRM Mo 192662. C. NRM Mo 192663. D–F. Enigmaticolus semisulcata (Martin, 1933), imperfect specimens in apertural and abapertural views. D. NRM Mo 192632. E. NRM Mo 192586. F. NRM Mo 192633. G. Enigmaticolus sp., NRM Mo 192640, specimen with broken apertural base, abapertural and apertural view. H. Mitridae gen. et sp. indet., NRM Mo 192639, imperfect specimen, abapertural view. I. Terebridae gen. et sp. indet., NRM Mo 192627, fragment of spire, lateral view. J, K. Acanthodaphne? sp., imperfect specimens in apertural view. J. NRM Mo 192637. K. NRM Mo 192638. L. Gemmula sp., NRM Mo 192417, imperfect specimen, apertural view. M. Xylodiscula? sp., NRM Mo 192619, specimen embedded in rock matrix in apical view. N. Volvulella aff. minoensis Itoigawa, 1958, NRM Mo 192641, nearly complete specimen, apertural view. O. Ringiculidae gen. et sp. indet., NRM Mo 192642, imperfect specimen, apertural view.