Hikidea svalbardensis, Nakrem, 2017

Nakrem, Hans Arne, 2017, Gastropods from the Late Jurassic - Early Cretaceous seep deposits in Spitsbergen, Svalbard, Zootaxa 4329 (4), pp. 351-374 : 355

Hikidea svalbardensis sp. nov.

( Fig. 3A–C )

2015 Cantrainea sp.; Hryniewicz et al. 2015a, table 1.

Diagnosis. Shell turbiniform, with maximum convexity in the lower part of lateral flank. Concave ramp wide but weakly expressed at the adapical suture. Surface smooth apart from some blunt spirals or shallow spiral bands and strongly prosocline growth lines.

Holotype: PMO 217.574, H = 5.4 mm, W = 5.1 mm.

Type locality and age: Seep #9, Sassenfjorden, Svalbard; late Berriasian, Early Cretaceous.

Other material: Three additional specimens from the type locality.

Description. Protoconch unknown. Shell turbiniform with three whorls preserved, convex with weak angulation in the abapical part of the flank. Weakly expressed wide ramp at the adapical suture. Adult shell surface smooth apart from some weak spirals and/or blunt spiral bands in the abapical part of the flank. Growth lines strongly prosocline. Aperture, umbilicus, inner and outer lip not preserved.

Remarks. Hikidea svalbardensis differs from other species of the genus ( H. osoensis , H. omagariensis and H. yasukawensis ) by attaining the maximum convexity in the lower portion of the flank (vs. middle portion in the other species) which is ornamented by blunt, band-like spirals.

Distribution. Type locality only.

Etymology. After the Svalbard Archipelago.

Figures

FIGURE 3. A – C. Hikidea svalbardensis sp. nov. Seep deposit # 9, Sassenfjorden, Svalbard; late Berriasian (Early Cretaceous); holotype (PMO 217.574). D – H.? Pectinodonta borealis sp. nov. Seep deposit # 9, Sassenfjorden, Svalbard; late Berriasian (Early Cretaceous). D, E, G. Holotype (PMO 217.516). F, H. Internal mould (PMO 224.752).