Heliacus berthae ( Boettger, 1902 )

Harzhauser, Mathias & Landau, Bernard, 2023, The Architectonicidae and Mathildidae (Gastropoda, Heterobranchia) of the Miocene Paratethys Sea-victims of the Miocene Climatic Transition, Zootaxa 5370 (1), pp. 1-74 : 27-29

Heliacus berthae ( Boettger, 1902)

Figs 14A–D

* Solarium (Torinia) berthae n. sp. — Boettger 1902: 115.

Solarium (Torinia) berthae Boettger —Boettger 1907: 136.

Solarium (Torinia) criticum n. sp. —Boettger 1907: 137.

Solarium (Pseudotorinia) berthae (Boettger) — Cossmann 1916: 166, pl. 12, figs 7–9.

Solarium (Solariaxis) criticum (Boettger) — Cossmann 1916: 170, pl. 12, figs 16–18.

Solarium (Pseudotorinia) berthae (Boettger) —Zilch 1934: 217, pl. 7, figs 15a–b.

Solarium (Solariaxis) criticum (Boettger) —Zilch 1934: 218, pl. 7, figs 18 a–c.

Architectonica (Solariaxis) criticum Boettger — Marinescu 1961: 533, pl. 5, fig. 22.

Architectonica (Pseudotorinia) berthae (Boettger, 1901) — Atanacković 1985: 98, pl. 23, figs 11–13.

berthae ( Solarium ) Boettger, 1902 — Bieler & Petit 2005: 24.

criticum ( Solarium ) Boettger, 1906— Bieler & Petit 2005: 31.

non Architectonica (Pseudotorinia) berthae (Boettger in Cossmann)— Anderson 1960: 49, pl. 9, figs 1, 1a–b [= Heliacus ].

non Architectonica (Pseudotorinia) berthae (Boettger in Cossmann). — Janssen 1967: 133, pl. 7, figs 4a–b [= Heliacus ].

non Solarium berthae Bttgr. — Csepreghy-Meznerics 1969a: 69, pl. 1, figs 11, 14 [= Heliacus miser ( Dujardin, 1837) ].

non Solarium berthae Boettger — Csepreghy-Meznerics 1969b: 20, pl. 2, figs 16, 20, 24 [= Heliacus miser (Dujardin, 1937) ].

non Architectonica (Pseudotorinia) misera berthae (Boettger, 1901) — Bałuk 1975: 118, pl. 13, figs 7–8 [= Heliacus miser ( Dujardin, 1837) ].

Type material. Lectotype (designated by Zilch 1934: 217): SMF 372698 (XII 2372a), SL: 2.3 mm, MD: 4.5 mm, Senckenberg Museum, Frankfurt/Main, Germany, Coşteiu de Sus ( Romania), illustrated in Zilch 1934: pl. 7, fig. 15, Figs 14A 1 –A 3 . SMF XII 2575a, SL: 2.25 mm, MD: 4.25 mm, Senckenberg Museum, Frankfurt/Main, Germany, Coşteiu de Sus ( Romania), holotype of Solarium (Torinia) criticum Boettger, 1907 , illustrated in Cossmann (1916: pl. 12, figs 16–18); the specimen is lost (Zilch 1934: 218).

Illustrated material. NHMW 1869/0001/0708a, SL: 3.5 mm, MD: 6.0 mm, Coşteiu de Sus ( Romania), Figs 14B 1 –B 3 . NHMW 1869/0001/0708b, SL: 3.5 mm, MD: 7.6 mm, Coşteiu de Sus ( Romania), Figs 14C 1 –C 3 . NHMW 1868/0001/0531a, SL: 4.9 mm, MD: 6.4 mm, Lăpugiu de Sus ( Romania), Figs 14D 1 –D 3 .

Additional material. 17 spec., NHMW 1868 /0001/0531, Lăpugiu des Sus ( Romania) .

Description. Small, lentiform shell with low conical spire. Protoconch heterostrophic, medium-sized of <1 visible whorl (diameter 1.0 mm). Teleoconch of 2.5 whorls. Teleoconch whorls faintly convex, initially with SSC, UPC and LPC of roughly equal strength, relatively coarsely beaded; beads axially arranged. Later whorls with two beaded MCs (upper one more prominent). Axial growth lines forming weakly cancellate sculpture on last whorl. Periphery with prominent, strongly beaded, rounded keel formed by LPC. Beaded IPC forming second angulation closely below. Base with three beaded spiral cords on basal field separated by relatively wide interspaces and broader, indistinctly beaded PUC. UC prominent, overhanging umbilicus, delimited from PUC by deep groove. Umbilicus moderately wide (~26% of MD), cylindrical. Umbilical wall with delicate growth lines. Aperture circular; CG shallow; PG absent.

Synonyms. Solarium (Torinia) criticum Boettger, 1907 was separated by Boettger (1907) from H. berthae based on the presence of only one keel. The illustrations in Cossmann (1916) and Zilch (1934), however, show a distinct, though weaker, second keel formed by the IPC. Comparing these illustrations those herein of Heliacus berthae does not support a separation, and we consider Solarium (Torinia) criticum Boettger, 1907 as subjective junior synonym of Heliacus berthae .

Discussion. This species has been placed in Pseudotorinia by several authors. However, the second keel formed by the IPC, and the conical spire suggest placement in Heliacus . Moreover, the relatively large, oblique protoconch differs from the smaller and relatively depressed protoconchs seen in many Pseudotorinia species (compare extant Heliacus and Pseudotorinia species in Bieler 1993).

This species could be mistaken for a juvenile Heliacus miser ( Dujardin, 1837) and the spire whorls are very similar in both species at the same growth stage. The delicate spiral cord between the two keels in P. miser is not developed in juvenile shells, which increases the similarity. However, in P. miser the beads on the base are much coarser and there are short axial folds on the PUC. In addition, the tuberculate periphery of H. berthae differs from the comparatively smooth keel in H. miser . The Late Oligocene Solarium mariae Báldi in Báldi, Kecskeméti, Nyirő & Drooger, 1961 is distinguished by its wider umbilicus, stronger axial folds on the base and a prominent UPC (see Báldi in Báldi et al. 1961: 97, pl. 4, figs 10a–c. Báldi 1973: 256, pl. 27, figs 5–6).

Distribution. Known so far only from the middle Badenian (late Langhian) of the Central Paratethys Sea. Occurrences from the Middle Miocene of the North Sea Basin ( Anderson 1960; Janssen 1967) are based on misidentifications (see Janssen 1972).

Central Paratethys Sea. Middle Miocene (Badenian): Pannonian Basin: Szokolya ( Hungary) ( Báldi 1960); Hrvaćani ( Bosnia and Herzegovina) ( Atanacković 1985); Bahna-Orşova Basin: Ogaşul Curchia ( Romania) ( Marinescu 1961); Făget Basin: Coşteiu de Sus, Lăpugiu de Sus ( Romania) (Boettger 1907).

Figures

FIGURE 1. Descriptive terms used in descriptions of Architectonicidae (modified from Bieler 1993).

FIGURE 3. Descriptive terms used in descriptions of Mathildidae.

FIGURE 14 A1–A3. Heliacus berthae (Boettger, 1902), lectotype, SMF 372698, Coşteiu de Sus (Romania). B1–B3. Heliacus berthae (Boettger, 1902), NHMW 1869/0001/0708a, Coşteiu de Sus (Romania). C1–C3. Heliacus berthae (Boettger, 1902), NHMW 1869/0001/0708b, Coşteiu de Sus (Romania). D1–D3. Heliacus berthae (Boettger, 1902), NHMW 1868/0001/0531a, Lăpugiu de Sus (Romania).