Gemmula sp.

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 : 940

Gemmula sp.

Fig. 20L .

Material.— One specimen from block E ( NRM Mo 192417: H = 24.5 mm, W = 14.0 mm). Upper Miocene of the “shale quarry” within the Northern Cement Corporation quarry in Pangasinan province, Luzon, Philippines .

Remarks.—This fragmentary specimen (3.5 whorls) is quite similar to Gemmula sp. indet. illustrated by Matsubara (2011: pl. 3: 7) from Miocene shallow marine deposits of the Hokutan Group in the Tajima area, Hyôgo Prefecture, southwest Japan. Gemmula osawanoensis Tsuda, 1959 , from Middle Miocene deep-water sediments of the Higashibessho Formation in Toyama Prefecture, central Japan ( Amano et al. 2004: fig. 5.15), appears to have more distinctive spiral ornament on the base, though the absence of such ornament from the Philippine specimen might be a preservational artifact. The Gemmula species from the Miocene Yunabaru clay on Okinawa illustrated by MacNeil (1960: pl. 5) have fewer but stronger axial ribs on the central spiral cord than the specimens reported here. Further similar fossil species include Gemmula granosus ( Helbling, 1779) illustrated in Noda (1988: pl. 13: 9a, b) from the Pliocene of Okinawa, Japan, and Pleurotoma woodwardi Martin, 1883 from Java, Indonesia (Martin 1891–1906: 37, pl. 4: 91–96). A bit more compact are Bathytoma hetzeli Martin, 1933 , from the Upper Miocene of Buton, Indonesia ( Martin 1933: 21, pl. 3: 16), and Cosmasyrinx monilifera Marwick, 1931 from Miocene bathyal deposits in New Zealand ( Beu and Maxwell 1990: 250, pl. 27: S). Among extant taxa, perhaps most similar are Gemmula cosmoi (Sykes, 1830) , which occurs from Sagami Bay to Kyushu, in 50–350 m depth, and G. kieneri ( Doumet, 1840) , which occurs from Choshi (Pacific central Honshu) southward to the Philippines ( Hasegawa et al. 2000).

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.