Bathyacteon valdesi

Helwerda, Renate A., 2015, Acteonidae, Bullinidae and Ringiculidae (Gastropoda: Heterobranchia) from the Plio-Pleistocene of the Philippines, Zootaxa 3990 (2), pp. 197-220 : 201

publication ID	https://doi.org/ 10.11646/zootaxa.3990.2.2
publication LSID	lsid:zoobank.org:pub:BDF1BC11-4848-4858-99DC-0336A5FBEE2B
DOI	https://doi.org/10.5281/zenodo.6116497
persistent identifier	https://treatment.plazi.org/id/03FA878C-9514-FE4E-FF26-E6F1027DCD90
treatment provided by	Plazi
scientific name	Bathyacteon valdesi
status

Treatment

Bathyacteon valdesi View in CoL nov. spec.

( Figures 4–5 View FIGURE 1 – 7. 1 )

Type material. Holotype RGM 961.786 (Type locality). Paratype RGM 961.746 (Type locality) and 7 paratypes RGM 961.848 (Type locality).

Other material. Anda3 (1) RGM 961.781, Anda6 (8) RGM 961.782, AndaDeVos (65) RGM 961.783, AndaClif3 (3) RGM 961.784, Roxas (6) RGM 961.785.

Type locality. AndaDeVos.

Derivatio nominis. Named after Dr. Ángel Valdés, who made a major contribution to our knowledge on Acteonidae and other “cephalaspid” heterobranchs.

Diagnosis. Shell wide, thick; H 2.44 mm, W 1.78 mm; protoconch large, low, 1.2 whorl, DP 0.80 mm; nucleus large, DN 0.38 mm; teleoconch weakly shouldered, smooth except for growth lines and few spiral grooves on base; aperture wide; inner lip and columella covered with callus; umbilicus closed.

Description. Shell small, relatively wide for a species of Acteonidae , rather thick-shelled, with a rounded shoulder and convex sides. Largest specimen has a total of 2.8 whorls, including a protoconch of 1.2 whorl. Protoconch smooth, shiny, margin indistinct. Teleoconch glossy, smooth except for weak prosocyrt growth lines and 3–5 weak spiral grooves without punctuations on base. Aperture wide and rather short, teardrop-shaped. Parietal callus present, thickest on columella. One weak fold present on columella in large specimens. Umbilicus closed.

Differentiation. Bathyacteon aequatorialis (Thiele, 1925) is similar to B. valdesi nov. spec. in its general shape and size, but B. aequatorialis (Thiele, 1925) has a smaller protoconch, which is usually corroded, but appears to have 0.8 whorl and a diameter of 500 µm. Furthermore, there are weak, punctuated spiral grooves, with large gaps in between, present on most of the teleoconch whorl in Bathyacteon aequatorialis (Thiele, 1925) . A lack of punctuated spiral grooves is rare within Acteonidae . It also occurs in Pupa nitidula (Lamarck, 1816) , but this species has a coeloconoid spire, a strong, double columellar fold and a lamella on the parietal area.

Remarks. This species is tentatively placed in genus Bathyacteon , because it resembles the type species B. aequatorialis (Thiele, 1925) much more strongly than any other Acteonidae , with respect to its shell shape and sculpture. This placement is tentative, because Bathyacteon is delimited from other acteonid genera using radular characters.