Provanna azurini, Kiel & Aguilar & Kase, 2020

Kiel, Steffen, Aguilar, Yolanda M. & Kase, Tomoki, 2020, Mollusks from Pliocene and Pleistocene seep deposits in Leyte, Philippines, Acta Palaeontologica Polonica 65 (3), pp. 589-627 : 620

Provanna azurini sp. nov.

Fig. 33A–C .

Zoobank LSID: urn:lsid:zoobank.org:act:F26418F1-EC73-4512-A485-35241B398A0D

Etymology: In honour of Emolyn Azurin (Philippine Mining and Geoscience Bureau, Quezon City, Philippines) for safely driving us during the field work in Leyte.

Type material: Holotype NMNS PM 28452 , shell with three whorls and spiral sculpture . Paratypes: NMNS PM 28453 , 28454 , shells preserving few whorls and different sculptural styles from the type locality .

Type locality: Liog-Liog Point , Leyte, Philippines .

Type horizon: Upper Pliocene part of the Bata Formation .

Material.— Four specimens from the Pliocene of Liog-Liog Point : the type material and NMNS PM 28456 (six individuals, some of them fragmentary) .

Dimensions (in mm).—NMNS PM 28452, H = 3.2 (at three whorls), W = 1.8. Widest available whorl fragment (unnumbered): W = 3.0.

Diagnosis.—Small for genus; tall, slender shell, whorls angular, with two equally strong spiral cords per whorl, no axial sculpture; three spiral cords of decreasing strength on base, upper one marking basal margin; aperture slightly oval.

Description.—Tall, slender shell composed of at least 3 whorls, reaching at least 4 mm in height; whorls profile angular, shoulder nearly straight and smooth, two distinct spiral cords per whorl, with broad, smooth interspace; base with three further spiral cords of decreasing strength and beaded appearance, the uppermost marks the basal margin; aperture slightly oval with small, short siphonal notch, columellar and parietal lip callused.

Remarks.— Provanna species having exclusively spiral ornament are rare. The most similar extant species are Provanna macleani Warén and Bouchet, 1989 from seeps off of Oregon, USA ( Warén and Bouchet 1989), and Provanna cingulata Chen, Watanabe, and Ohara, 2018 , from the Shinkai seep field in the southern Mariana Trench ( Chen et al. 2018). Provanna macleani differs from Provanna azurini by having four to five spiral cords per whorl, whereas Provanna azurini has only two. Provanna cingulata has an increasing number of spiral cords per whorl, starting with two spiral cords on very early whorls. However, the whorls of Provanna cingulata are more angular and the species is overall less slender than Provanna azurini . Among fossil species, Provanna antiqua Squires, 1995 from Oligocene seeps in Washington state, USA, and northern Peru ( Squires 1995; Kiel et al. 2019), has very variable sculpture including specimens with almost exclusively spiral ornament. But as in the extant P. macleani , these are more numerous (3–4) than in Provanna azurini .

Stratigraphic and geographic range.—Late Pliocene, Leyte, Philippines.

Figures

Fig. 33. Provannid gastropods from the late Pliocene Liog-Liog Point seep deposit in Leyte, Philippines. A–C. Provanna azurini sp. nov. A. Paratype NMNS PM 28453 in apertural view. B. Paratype NMNS PM 28454 in abapertural view. C. Holotype NMNS PM 28452, specimen in apertural view with three preserved whorls but poorly preserved sculpture. D. Desbruyeresia? sp., NMNS PM 28457 in abapertural view.