Granosolarium semilaevis
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Heterostropha
Architectonicidae
Granosolarium
Granosolarium semilaevis

description: Granosolarium semilaevis (Sacco, 1892)
Figs 4K, 13A–D
Solarium millegranum Lam. — Ĥrnes 1848: 22 [non Granosolarium millegranum (Lamarck, 1822)].
Solarium millegranum Lam. —Ĥrnes 1856: 465, pl. 46, figs 4a–c [non Granosolarium millegranum (Lamarck, 1822)].
Solarium millegranum Lam. —Neugeboren 1856: 194 [non Granosolarium millegranum (Lamarck, 1822)].
* [Solarium (Granosolarium) millegranum] var. semilaevis Sacc. —Sacco 1892: 61.
Solarium (Granosolarium) millegranum Lmk. —Boettger 1907: 135 [non Granosolarium millegranum (Lamarck, 1822)].
Solarium millegranum Lmk. —Montanaro Gallitelli & Tacoli 1951: 177, pl. 2, fig. 5 [non Granosolarium millegranum (Lamarck, 1822)].
Architectonica (A [rchitectonica].) millegranum (Lm.) —Sieber 1958: 139 [non Granosolarium millegranum (Lamarck, 1822)].
Architectonica (Architectonica) millegranum Lamarck — Marinescu 1961: 532, pl. 5, figs 20a–f [non Granosolarium millegranum (Lamarck, 1822)].
Solarium millegranum Lamarck, 1822 —Zelinskaya et al. 1968: 133, pl. 34, figs 9–12 [non Granosolarium millegranum (Lamarck, 1822)].
semilaevis (Solarium) Sacco, 1892— Bieler & Petit 2005: 62.
non Solarium millegranum Lam. (?)— Friedberg 1923: 414, pl. 25, fig. 6 [= Nipteraxis exmoniliferus (Sacco, 1892)].
non Architectonica (Solariaxis) millegranum Lamk. — Korobkov 1955: plate captions, pl. 13, figs 19a–c [= Niperaxis exmoniliferus (Sacco, 1892)].
Type material. Holotype: NHMW 1846 /0037/0428a, SL: 6.9 mm, MD: 15.5 mm, M̂llersdorf (Austria), illustrated in Ĥrnes (1856, pl. 46, figs 4a–c), Figs 13C 1 –C 2.
Illustrated material. NHMW 1846/0037/0428b, SL: 4.3 mm, MD: 11.7 mm, M̂llersdorf (Austria), Figs 13A 1 –A 2. NHMW 2013/0078/0113a, SL: 3.1 mm, MD: 10.4 mm, Baden (Austria), Figs 13B 1 –B 2. NHMW 2013/0078/0113b, SL: 3.0 mm, MD: 9.8 mm, Baden (Austria), Figs 13D 1 –D 2. NHMW 1846/0037/0428d, SL: 3.7 mm, MD: 10.3 mm, M̂llersdorf (Austria), Fig. 4K.
Additional material. 1 spec. NHMW 1846 /0037/0428c, M̂llersdorf (Austria).
Revised description. Shell small, flattened, discoidal, periphery carinate, with flattened cyrtoconoid spire. Protoconch heterostrophic, large, of 1.2 visible whorls (diameter 1.2 mm). Teleoconch of about 4.5 whorls. SSC, UPC and LPC narrow, beaded. Two or three beaded spiral cords become successively intercalated between peripheral cords; three to four beaded spiral cords appear on mid-field separated by delicately beaded spiral threads. LPC forming sharp crenulated carina, also serving as upper point of whorl attachment. Base weakly concave below carina; laterally three finely beaded spiral cords (including LPC) and up to five delicate beaded spiral threads intercalated; medially three more coarsely beaded spiral cords; UC fine, narrow, sunken into and overhanging umbilicus. Umbilicus very wide (~40–41% of total diameter). Umbilical wall bearing prosocline growth lines. Aperture small, rounded, sharply pointed at peripheral keel; CG and PG absent.
Discussion. This species was considered conspecific with the Late Miocene to Pliocene (Proto-)Mediterranean Granosolarium millegranum (Lamarck, 1822) by most authors. Only Sacco (1892) recognized that the specimen from the Middle Miocene of the Vienna Basin illustrated by Hörnes (1856) was not conspecific with G. millegranum and introduced the varietal name semilaevis for it. Granosolarium millegranum differs from G. semilaevis in its much larger size (max. diameter 17.5 mm versus 10.4 mm), more sharply carinate periphery, the narrower umbilicus, and the more reduced sculpture of beads on the spiral cords of the dorsal and ventral side (e.g., Cavallo & Repetto 1992: 152, fig. 419; Bogi et al. 2002: 35, figs 21–22; Chirli 2013: 12, pl. 4, figs 4–9).
Paleoecology. All Austrian specimens drive from clays of the Baden Formation, which formed in middle to outer neritic environments with up to 210 m water depth (Kranner et al. 2021).
Distribution. Only known from the Langhian equivalent of the Badenian of the Central Paratethys Sea.
Central Paratethys Sea. Middle Miocene (Badenian): Alpine-Carpathian Foredeep: Žabčice (Czech Republic) (Montanaro Gallitelli & Tacoli 1951); Vienna Basin: Baden, M̂llersdorf (Austria) (Ĥrnes 1856); Făget Basin: Coşteiu de Sus, Lăpugiu de Sus (Romania) (Boettger 1907), Bahna-Orşova Basin: Racovăţ, Iloviţa (Romania) (Marinescu 1961).
description: Published as part of Harzhauser, Mathias & Landau, Bernard, 2023, The Architectonicidae and Mathildidae (Gastropoda, Heterobranchia) of the Miocene Paratethys Sea-victims of the Miocene Climatic Transition, pp. 1-74 in Zootaxa 5370 (1) on pages 25-27, DOI: 10.11646/zootaxa.5370.1.1, http://zenodo.org/record/10147814