Turritella saposa Olssoni 1944

Turritella saposa Olsson, 1944 (Figure 5 (h))

Turritella saposa Olsson 1944, 71, pl. 10, figs. 4, 6, 7, 9, 11, 12.

Turritella saposa austera Pilsbry 1944, 139, pl. 9, figs. 5 – 7.

Diagnosis

Whorls with three strong primary spiral cords, nearly evenly spaced between sutures. Basal primary spiral cord bracketed by strong secondary spiral cords.

Emended description

Estimated shell length to 30 mm, pleural angle about 20°. Protoconch unknown. Spire with estimated 10 whorls. Whorls straight-sided to convex, imbricate, spiral formula from later teleoconch whorls only D1u1C 1t 1B1s1A1, becoming v1D1u1C 1t 1B1s1s2A1; subsutural spiral cords, if present, not preserved. Spacing formula C30B55A86 (n = 1). Lateral growth line weakly prosocline, nearly orthocyrt. Lateral sinus very shallow, apex centred on spiral ‘ B ’. Base not preserved. Allmon formula?-3-S-B-P.

Remarks

In the Caballas Formation, specimens of Turritella saposa occur together with specimens of T. capistrata sp. nov. and Cristispira caballasensis sp. nov. In northern Peru, specimens of T . saposa occur alone in the upper Campanian lower Tortuga Formation (Jaillard et al. 2005). Turritella desolata Olsson, 1944, which closely resembles T. capistrata sp. nov., occurs alone in the Maastrichtian ‘ Baculites ’ beds of the Tortuga Formation. Cristispira prechira (Olsson, 1944), which is similar to C. caballasensis, occurs alone in the upper Campanian La Mesa Formation (Jaillard et al. 2005).

Specimens of Turritella saposa austera Pilsbry, 1944 were described from shaley limestone beds near Isla Chonta, along the Rio Pachitea in eastern Peru (Singewald 1926; Pilsbry 1944), in beds now recognised as the Upper Cretaceous Chonta Formation (CGS Consultores Associados S.A 1997).

Material

UWBM 107602, B8770, L (15.5), W (10.4); UWBM 107640, B8770, L (15.9), W (6.2).

Occurrence

Upper Cretaceous, Tortuga Formation, Talara Basin, northern Peru, and Chonta Formation, eastern Peru; Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.