Humptulipsia nobuharai, Kaim, Andrzej, Jenkins, Robert G., Tanabe, Kazushige & Kiel, Steffen, 2014

Kaim, Andrzej, Jenkins, Robert G., Tanabe, Kazushige & Kiel, Steffen, 2014, Mollusks from late Mesozoic seep deposits, chiefly in California, Zootaxa 3861 (5), pp. 401-440 : 417-418

Humptulipsia nobuharai sp. nov.

( Fig. 7 G, J–M)

Type locality and strata: Sada Limestone, Shikoku, Japan; Campanian-Maastrichian (Late Cretaceous); for details see Nobuhara et al. (2008).

Holotype: UMUT MM31170, two moderately well-preserved whorls 26.8 mm high and 15.4 mm wide.

Paratypes: UMUT MM31230, adult specimen, UMUT MM31171, UMUT MM31172, two juvenile shells, UMUT MM31173 fragmentary specimen displaying the humptulipsid slit on the shell base.

Additional material: Many unprepared specimens from the type locality. This gastropod occurs in mass accumulations at the type locality.

Diagnosis. Tall shell with largest whorl diameter in mid-flank. Adult shell smooth apart from prosocyrt growth. Shell base with narrow slit in its abapical portion.

Description. Tall shell with largest whorl diameter at mid-whorl. Protoconch and juvenile teleoconch unknown. Adult shell smooth apart from prosocyrt growth lines. Shell base with narrow slit in its abapical portion. Suture weakly incised. Aperture poorly preserved, drop-shaped.

Remarks. Humptulipsia nobuharai is the third species of Humptulipsia described so far. The type species H. raui is known from Eocene/Oligocene hydrocarbon seeps in Washington state (Kiel 2008) and differs from H. nobuharai in having a much wider slit that is located much higher on the whorls. Humptulipsia macsotayi Kiel et al., 2010 described from Hauterivian (Early Cretaceous) presumed seep carbonates in southeastern France (Kiel et al. 2010) differs from H. nobuharai by being ornamented throughout the entire shell ontogeny. We include Humptulipsia in the Hokkaidoconchidae due to the hokkaidoconchid-like ornamentation of the juvenile shell in H. raui (see Fig. 1.9 in Kiel 2008 and Fig. 7 H herein). A slit similar to that of Humptulipsia is present in the members of family Pseudolividae de Gregorio, 1880, which differ, however, in ornamentation style of the early whorls (see e.g., Pacaud & Schnetler 1999) and are known in the fossil record from Maastrichtian, Late Cretaceous ( Kaim & Beisel 2005).

Etymology. For Takami Nobuhara who made the field trip to the Sada Limestone deposit possible.

Figures

FIGURE 7. A – D. Ascheria? sp. from Eocene-Miocene Joes River seep sites in Barbados. A – C. NMB-H 20154, 20155, 20158 from Loc. 10039. D. NMB-H 20162 from Loc. 10070. E-F. Ascheria gigantea (Kiel et al. 2008) from? Early Cretaceous seep carbonates at East Berryessa, Napa County, California, USA. E. Holotype (UCMP 555095). F. Paratype (UCMP 555096), the arrow indicates subsutural constriction. G, J – M. Humptulipsia nobuharai sp. nov. from seep carbonates in Campanian- Maastrichtian (Late Cretaceous) Sada Limestone, Shikoku, Japan. G. UMUT MM 31173 fragmentary specimen displaying the humptulipsid slit (arrow) on the shell base. J. Holotype (UMUT MM 31170), the arrow indicates humtulipsid slit. K. Paratype (UMUT MM 31230). L. Paratype (UMUT MM 31171). M. Paratype (UMUT MM 31172). H, I. Humptulipsia raui (Goedert & Kaler, 1996) from seep carbonates in Western Washington State. H. Possibly a juvenile specimen (USNM 531408) of H. raui from late Oligocene Lincoln Creek Formation. I. Adult specimen (UWBM 97854) from middle Eocene Humptulips Formation (see also Kiel 2008).