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

description: Solatisonax? kostejana (Boettger, 1907)
Figs 4G, 12A–D
* Solarium (Granulosolarium) kostejanum n. sp. —Boettger 1907: 135.
Solarium (Solariaxis) kostejense Boettger — Cossmann 1916: 170, pl. 12, figs 10–12.
Solarium (Solariaxis) kostejanum (Boettger) —Zilch 1934: 218, pl. 7, figs 17a–c.
Architectonica (Solariaxis) kostejanum Boettger — Marinescu 1961: 533, pl. 5, figs 21a–c.
kostejanum (Solarium) Boettger, 1906— Bieler & Petit 2005: 45.
kostejense (Granosolarium) (Boettger)— Bieler & Petit 2005: 45.
non Architectonica (Solariaxis) kostejanum (Boettger, 1906) — Atanacković 1985: 98, pl. 23, figs 14–17 [= Niperaxis exmoniliferus (Sacco, 1892)].
non Architectonica (Solariaxis) kostejana (Boettger, 1907) — Bałuk 2006: 195: pl. 7, figs 6–7 [= Pseudotorinia marthae (Boettger, 1902)].
Type material. Lectotype (designated by Zilch 1934: 218): SMF 372696 (XII 2370 a), Senckenberg Museum, Frankfurt/Main, Germany, Coşteiu de Sus (Romania), illustrated in Zilch (1934: pl. 7, fig. 17), Figs 12D 1 –D 2.
Illustrated material. NHMW 2023/0269/0001, SL: 3.3 mm, MD: 8.1 mm, Bad Vöslau (Austria), Figs 12A 1 –A 2. NHMW 2023/0269/0002, SL: 3.8 mm, MD: 10.1 mm, Bad Vöslau (Austria), Figs 12B 1 –B 2. NHMW 2012/0229/0049b, SL: 5.1 mm, MD: 12.3 mm, Traiskirchen (Austria), Figs 4G, 12C 1 –C 3.
Description. Shell small, solid, relatively flattened lentiform, periphery angled, profile weakly convex above, weakly convex below. Protoconch heterostrophic, medium-sized, of 1.2 visible whorls (diameter 1.0 mm). Transition to teleoconch marked by protoconch lip. Teleoconch of 3.75 whorls. First quarter whorl smooth, UPC and LPC appear simultaneously, then SSC appears after half a whorl. MCs only appear on second teleoconch whorl. Number of MCs increasing to 5–7 on later whorls by bifurcation. LPC forming convex, finely crenulated keel, also serving as upper point of whorl attachment. Base with relatively broad LPC and slightly weaker, beaded IPC; weak, beaded spiral thread intercalated between LPC and IPC. Basal field with three additional densely beaded spiral cords. Broad flat PUC with prominent axial ribs separated from spiral cords by narrow groove. PUC may be bisected by additional middle groove. Distinct but narrow groove delimits UC from proxumbilical cord. UC prominent, axially elongated, overhanging umbilicus. Umbilicus wide (25–30% of MD), narrowly funnel-shaped. Umbilical wall with delicate spiral threads. Aperture small, rounded, angled at LPC, with moderately deep CG, PG absent.
Discussion. This species is characterized by its broad inner basal field with axial ribs and the depressed, lenticular outline. Both features allow a separation from the otherwise similar Nipteraxis exmoniliferus, which bears also more spiral cords on the basal field. Solatisonax? kostejana is superficially reminiscent of Nipteraxis Cossmann, 1916 but its basal field cords have been pushed peripherally by the broad inner basal field, and it lacks the tubercular UC characteristic of Nipteraxis. Solarium kostejense is an unjustified emendation of Solarium kostejanum by Cossmann (1916: 170).
The Pliocene Mediterranean ‘ Solarium’ zanclea G. Seguenza, 1876 differs from Solatisonax? kostejana mainly in its coarser axial sculpture on the basal field (e.g., L. Seguenza 1903: pl. 17, figs 11–12; Rindone 1991: figs 1a–c). ‘ Solarium’ zanclea seems to be still living in the Mediterraean Sea but is confused with Solatisonax alleryi (G. Seguenza, 1876) (e.g., Bogi et al. 2002: figs 7–9; https://www.marinespecies.org/aphia.php?p=image&tid=138776 &pic=99328). Solatisonax alleryi (G. Seguenza, 1876), as described by L. Seguenza (1903: pl. 17, figs 6–8), lacks the broad inner basal field and does not develop axial ribs.
Paleoenvironment. The occurrence in the Baden Formation suggests middle to outer neritic water depths (Kranner et al. 2021).
Distribution. Only known from the Langhian equivalent of the Badenian in the Central Paratethys Sea. Central Paratethys Sea. Badenian (Middle Miocene): Făget Basin: Coşteiu de Sus (Romania) (Boettger 1907); Bahna-Orşova Basin: Ogaşul Curchia (Romania) (Marinescu 1961).
Genus Granosolarium Sacco, 1892
Type species. Solarium millegranum Lamarck, 1822; original designation by Sacco (1892: 59). Italy, Late Miocene to Pliocene.
Original diagnosis. “ Testa cingulis et cingulellis granosus ornate; saepe ad peripheram compressa, squamosa. Umbilicus amplus, cingulis granoso-nodosis circumscriptus ” [Shell with granulose spiral cords; often compressed at the periphery, scaly. The umbilicus is large, surrounded by granular-nodular spiral cords] (Sacco 1892: 59).
Revised description. “ Shell medium sized (c. 8–30 mm), flat conical with sharp keel and wide umbilicus (umbilical diameter ~c. 40% of shell diameter); in larger specimens whorls ± convex, concave on both sides keel. Fine growth lines on entire shell; upper side: usually with 4 distinct, beaded spiral cords with finer intermediate cords; followed by two stronger spiral cords in peripheral region (~upper and lower peripheral cords) and several intervening finer cords; this peripheral region variable: either uniformly continuous with the other spiral cords of the upper side with lower peripheral cord forming keel, or adjacent to upper side lower peripheral cord forming keel with concave region, or distinctly angled from upper side, upper peripheral cord forming keel and lower peripheral cord forms basal keel. Attachment of whorls at peripheral keel; nodes of keel often extended to form numerous narrow or few planar marginal ‘spines’; base: flat or convex with numerous fine, nodular spiral cords, broader towards umbilicus; innermost spiral cord of base (crenae umbilici) deeply recessed into umbilicus (appearing like umbilical wall cord), thereby area between crenae umbilici and next, often stronger proxumbical cord either nearly vertical or oblique to base; umbilical wall with growth lines, partly with very fine spiral sculpture ” (Bieler 1985a: 246; translated and slightly shortened from German) (Fig. 2).
Synonyms. Solariaxis Dall, 1892, type species Solarium elaboratum Conrad, 1833; original designation by Dall (1892: 323). Eocene, Alabama, USA. Claraxis Iredale, 1936, type species Claraxis illustris Iredale, 1936; by monotypy (Iredale, 1936: 327). Present-day, New South Wales, Australia.
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 23-25, DOI: 10.11646/zootaxa.5370.1.1, http://zenodo.org/record/10147814