Pseudotorinia Sacco, 1892

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 : 38-39

Genus Pseudotorinia Sacco, 1892

Type species. Solarium obtusum Bronn, 1831 ; original designation by Sacco (1892: 66). Pliocene, Italy .

Original diagnosis. “ This subgenus [Torinia] … is partly based on the special form of the operculum; therefore, in the absence of this, it is only provisionally that I doubtfully attribute some fossil forms to this group, which in the external characters recall the typical Torinia. In the case that this attribution is recognized, I would propose to constitute for these forms, so different from the real solariums, the new subgenus Pseudotorinia , for which I would select S. obtusum (Bronn) as type ” (Sacco 1892: 66, translated from Italian).

Revised description. “ Shell very small to small (usually 2–8 mm), lens-shaped with distinctly rounded base to coin-shaped with strongly angular base; umbilicus moderately to extremely wide (ca. 19–53% of shell diameter); distinct axial growth marks on entire shell surface, but usually only stronger than spiral ribs on early whorls; upper (apical) side: subsutural rib usually stronger and with coarser nodules than following 2–3 midribs; upper peripheral rib prominent and stronger than midribs; peripheral keel formed by very prominent lower peripheral rib (LPR), upper point of whorl attachment here; base: infraperipheral rib hardly stronger than following 2–3 narrow, distinctly demarcated spiral ribs; inner part of base formed by 3–4 wider spiral ribs, the outer one of which representing a ± prominent basal keel, the innermost (UC) surrounding umbilicus with strong nodules; umbilical wall with axial growth lines, in most cases without, rarely with 1–2 ± weak spiral ribs ” ( Bieler 1993: 276; see also Bieler 1985b: 91) ( Fig. 2 ).

Synonyms. Awarua Mestayer, 1930 (type species Omalaxis amoena Murdoch & Suter, 1906 ; Recent, New Zealand). Calodisculus Rehder, 1935 (type species Discohelix (Discosolis) retifera Dall, 1892 ; Pliocene, Florida).

Figures

FIGURE 2. Whorl cross-sections of Architectonicidae genera. All modified after Bieler (1993) except for Simplexollata, Basisulcata and Ammotectonica. Solatisonax? refers to Solatisonax? kostejana (Boettger, 1907), Bold genera are represented in the Paratethys Sea. SSC: subsutural cord, MC: mid cord(s), UPC: upper peripheral cord, LPC: lower peripheral cord, IPC: infraperipheral cord; UC: umbilical crenae; PUC: proxumbilical cord.