Type of wall: Spinose, spines are supported by spine collars which coalesce to form ridges. Pore concentrations ranging from 120-160 pores/50 μm2 test surface area and pore diameters range from around 1.2-2 μm.

Test morphology: Test trochospiral generally consisting of 3 whorls, it may became slightly planispiral in the last whorl, 5-6 chambers in the last whorl often strongly radially elongated and developing a knob-like distal termination, the size and development of this feature varies significantly among species, sutures straight and depressed to slightly arched on both sides. Aperture at the base of the last chamber interiomarginal but strongly tending to encompass the peripheral margin, a symmetrical arch, sometimes bordered by a distinct rim.

DISTINGUISHING FEATURES.— This genus differs from Globigerinella by the presence of markedly elongate and digitate chambers in the final whorl and by the higher pore concentrations ranging from 120-160 pores/50 μm2.

DISCUSSION.— The new genus Quiltyella Coxall and Spezzaferri has been erected to distinguish globigerinellids with distinctly elongate, sometimes extreme, chambers in the final whorl. Based on their typical wall texture and morphology, the species Q. nazcaensis and Q. clavacella cannot be attributed to existing digitate genera showing comparable morphologies such as Clavigerinella, Hastigerina/Hastigerinella and Beella. In particular, Quiltyella differs from Hastigerina/Hastigerinella by its higher pore concentration wall texture, and no evidence of triradiate spines typical of the latter (e.g., Hemleben and others, 1989). It differs from Clavigerinella by having a spinose wall texture with spines supported by spine collars which coalesce to form ridges typical of the bulloides-type wall texture (e.g., Hemleben and others, 1989; Hemleben and Olsson, 2006) and not weakly cancellate as in Clavigerinella (Coxall and Pearson, 2006). In the genus Beella the degree of elongation varies significantly between specimens (Coxall and others, 2007) whereas in adult specimens of Quiltyella all chambers of the last whorl are strongly elongated.

PHYLOGENETIC RELATIONSHIPS.— We tentatively propose that the genus evolved from Globigerinella roeglina n. sp. in mid-Oligocene Zone O4. However, it is possible that species of Quiltyella, like many other clavate/digitate forms discussed here, represent independent derivations from a globigerinellid form close to G. obesa.

GEOGRAPHIC DISTRIBUTION.— Highly restricted in some levels from the Paratethys and the Pacific Ocean.

STRATIGRAPHIC RANGE.— The stratigraphic range of Quiltyella is uncertain because its occurrence is extremely sporadic. Based on the limited data we suggest it ranges from the lower Oligocene Zone O4 to somewhere in the lower or middle Miocene (Quilty, 1976).

STABLE ISOTOPE PALEOBIOLOGY.— Although no data are available on the species belonging to this genus, Coxall and others (2007) based on isotopic evidence, suggested that digitate morphologies are typical of deep, subthermocline (>150 m) habitat, characterized by lower temperatures, reduced oxygen content, and enrichment of dissolved inorganic carbon.

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