Foveolaria, Szabó, 2016

Szabó, János, 2016, Gastropods of the Lower Jurassic Hierlatz Limestone Formation, part 2. Some new archaic type slit-bearing components from the fauna of the Hierlatz Alpe (Hallstatt, Austria) and the Bakony Mts (Hungary), Fragmenta Palaeontologica Hungarica 33, pp. 3-30 : 13-16

Genus Foveolaria n. gen.

Type species – Wortheniopsis (Sisenna) lokutensis Szabó, 2009 .

Derivation of name – Foveola (Lat.) = small hole, alluding to Pleurotomaria foveolata J. A. Eudes-Deslongchamp, 1849 , the earliest species name for a group of species, included here to Foveolaria n. gen.

Diagnosis – Turbiniform to conoidal or coeloconoidal, thin-walled shells of slightly convex whorls, being obscurely to clearly angular in latest growth stages. Base convex, narrowly phaneromphalous, some possibly anomphalous. Slit rather long, selenizone concave or flat between two threads at or below midwhorl as abapical belt of ramp or blunting angulation of whorl surface. Outer whorl face more or less concave. Abaxial rim of base angular, reinforced by cord or swollen belt, providing periphery. Apex blunt, protoconch low with evenly convex whorls. Ornament consisting of collabral riblets and spiral threads in high variability of patterns; granules frequently occurring at crossing points. Lunulae mostly on early selenizone. Growth lines delicate, more prosocline and prosocyrt adapically from selenizone, feebly prosocline to opisthocline abapically; prosocline and slightly opisthocyrt on base.

Description – Shells of Foveolaria approach turbiniform to conoidal shape with more or less gradate outline and variable spire height. They are very thin-walled, the early teleoconch whorls are simply convex but the latest whorls become obscurely to markedly angular at or below the midwhorl. The protoconch is poorly known; it has depressed turbiniform shape in the type species with evenly convex whorls and rather deeply impressed suture. The suture remains more or less impressed also along the subsequent whorls. The last whorl meets the base in a more or less rounded angulation that is reinforced by a swollen spiral belt or cord. The base as a whole has subconoidal to subglobular shape with feebly to strongly convex wall. In most species, a narrow phaneromphalus is observed; in some cases absence of the umbilicus seems probable. The slit is rather long as it is demonstrated by the only photo available ( FISCHER & WEBER 1997, Pl. 25, Fig. 12 ), it extends about 60° abaperturally. The selenizone is mostly concave or rarely flat between two threads at or, more commonly, somewhat below the midwhorl. Usually, it lies as abapical belt within the plane of the ramp and its abapical thread coincides with the ridge of angulation of the whorls but less frequently, it forms a third surface of the whorls, which blunts the angulation between the ramp and the outer face. Width of the selenizone is around 15% of the distance between two neighbouring sutures. In some species, the limiting threads are lacking or substituted by shallow striae on the last whorl. Outer face of the whorls is flat to concave and nearly parallel to the coiling axis; usually, its abapical rim corresponds to the periphery.

The ornament is composed of collabral riblets and spiral threads in high variability of patterns, frequently combined with granules and/or short riblets between pairs of spiral ridges at the crossing points. The short riblets are usually aligned collabrally forming false threads. Quirinii type ridges are also developed usually only on the base and mainly in the stratigraphically older (Sinemurian) species; rarely they occur also on the abapical part of the outer face. Lunulae occur mostly on the early selenizone parts, rarely present also on latest whorls. The growth lines are delicate, clearly prosocline and prosocyrt adapically from the selenizone but slightly prosocline to opisthocline and prosocyrt between the selenizone and the periphery, slightly prosocline and feebly opisthocyrt on the base.

Remarks – The shell form and many details are similar in Wortheniopsis and Foveolaria . Most reliable distinctive characters are the position of the selenizone, the orientation and shape of the growth lines (outer lip), the width of the outer face and the distribution of the quirinii type ridges on the shells. The selenizone is above the midwhorl in Wortheniopsis but at/or below the midwhorl in Foveolaria . Consequently, the width of the outer face is significantly narrower in Foveolaria than in Wortheniopsis . The growth lines (outer lip) are almost orthocline, just feebly prosocline in Wortheniopsis but clearly prosocline in Foveolaria in the belt adapically from the selenizone. The quirinii type ridges appear between the abapical edge of the selenizone and the axial region of the base in Wortheniopsis , however, they are present mostly on the base or, mainly in stratigraphically younger species, substituted by simple spiral threads in Foveolaria . In few cases, they are recognisable also on the outer face in strongly modified form, e.g. in F. hierlatzensis ( Szabó, 2009) or in F. kocsisi n. sp., with short riblet-like granules, rapidly diminishing abapically before reaching the next spiral ridge.

In common cases, the selenizone is the abapical belt of the ramp in Foveolaria , however, in some species, the selenizone does not lie in the plane of the ramp but blunts the angulation of the whorl surface like e.g. in Foveolaria conoidea n. sp. or Foveolaria globosa n. sp. (see below). If the selenizone is not clearly concave, like in Foveolaria hierlatzensis ( Szabó, 2009) , these forms may recall the shape of Bathrotomaria Cox, 1956 . However, in the latter genus, the selenizone is clearly convex, its adapical belt is part of the ramp and the abapical part belongs to the outer face, i.e. the selenizone itself is also mostly angular.

Species – With the name Pleurotomaria foveolata, J. A. EUDES-DESLONGCHAMPS (1849) covered six different but doubtlessly related shell forms that he regarded as varieties ( trochoidea , subturrita , turrita , procera , pinguis and ellipsoidea ). D’ORBIGNY (1854) raised these varieties, with some modifications, to species rank with indication of own authorship: Pleurotomaria subturrita , P. pinguis , P. ellipsoidea , P. subfaveolata , P. procera . The name subturrita in d’Orbigny’s interpretation contains also var. turrita J. A. Eudes-Deslongchamps ; the name subfaveolata is given instead of var. ellipsoidea J. A. Eudes-Deslongchamps. By the ICZN (1999) rules, the true author of these species names is J. A. Eudes-Deslongchamps, except subfaveolata , and the original species name ( foveolata ) becomes a nomen nudum. This name remains applicable only if a reviser (1) rejects any subdivision, or (2) reduces the rank of the varieties as FISCHER & WEBER (1997) have done it; in their species interpretation the former varieties are treated as “morphes”. In either cases lectotype or neotype selection is necessary like in FISCHER & WEBER (1997). Following the arguments in SZABÓ (2009, p. 28), J. A. EUDES-DESLONGCHAMPS (1849) varieties are treated as species also in this paper but without a deep revision.

Foveolaria trochoidea (J. A. Eudes-Deslongchamps, 1849) , p. 73, Pl. XV, Figs 2a, b . Foveolaria subturrita (J. A. Eudes-Deslongchamps, 1849) , p. 73, Pl. XV, Figs 3a, b . Foveolaria turrita (J. A. Eudes-Deslongchamps, 1849) , p. 74, Pl. XV, Figs 4a, b . Foveolaria procera (J. A. Eudes-Deslongchamps, 1849) , p. 74, Pl. XV, Figs 5a, b . Foveolaria pinguis (J. A. Eudes-Deslongchamps, 1849) , p. 75, Pl. XV, Figs 6a, b, c . Foveolaria ellipsoidea (J. A. Eudes-Deslongchamps, 1849) , p. 75, Pl. XV, Figs 7a, b . Foveolaria urkutensis ( Szabó, 2009) , p. 29, Figs 23 A-E.

Foveolaria hierlatzensis ( Szabó, 2009) , p. 30, Figs 24 A-F.

Foveolaria jancsii ( Szabó, 2009) , p. 31, Figs 25 A-P.

Foveolaria lokutensis ( Szabó, 2009) , p. 32, Figs 26 A-E.

Foveolaria bicarinata n. sp.

Foveolaria conoidea n. sp.

Foveolaria globosa n. sp.

Foveolaria suemegensis n. sp.

Foveolaria kocsisi n. sp.

Foveolaria sp.

Distribution – Sinemurian to Pliensbachian (Jurassic) in deposits of the Western Tethys and the Western European epicontinental seas.

Figures

Figs 4–14.Wortheniopsisspecies fromtheHierlatz LimestoneFormation.– 4–10.Wortheniopsisrakusi n.sp.from the Sinemurian to lowermost Pliensbachian interval (Lower Jurassic) of the Hierlatz Limestone in the Hierlatz Alpe,Hallstatt, Austria,GBA 2017/001/0002,all ×4.– 4. Dorsal view.– 5. Peristomal view.– 6. Basal view. – 7–9. Same views as 4–6 but in natural (×1) size. – 10. Details of the ornament on thespire whorls,×7.– 11–14.Wortheniopsis bakonyensis n. sp.,?Lower Sinemurian (Lower Jurassic) Hierlatz Limestone variety with rich micrite content, Csárdahegy, Úrkút, Bakony Mts, Hungary, GGIH J.08.3.1. – 11. Peristomal view of the holotype, ×4. – 12. Lateral view to show the best preserved outline part, ×4.– 13–14. The same views as in figures 11–12 but in natural (×1) size

Figs 1–3. The peculiar “quirinii type” ridges, occurring in Wortheniopsis Böhm, 1895, Foveolaria n. gen. and some probably related forms. – 1. Copy of KITTL’s (1899, p. 14, Fig. 2) sketch. – 2. The ridges on the outer face and on the base of Wortheniopsis rakusi n. sp. – 3. The ridges on the base of Foveolaria conoidea n. sp.

Figs 15–29. New species of Foveolaria n. gen. from the Sinemurian to lowermost Pliensbachian interval (Lower Jurassic) of the Hierlatz Limestone in the Hierlatz Alpe, Hallstatt, Austria. – 15–18. Holotype of Foveolaria bicarinata n. sp., GBA 2017/001/0003, all ×3.8. – 15. Dorsal view. – 16. Apical view. – 17. Basal view. – 18. Peristomal view. – 19–22. Holotype of Foveolaria conoidea n. sp., GBA 2017/001/0004, all ×4. – 19. Dorsal view. – 20. Apical view. – 21. Basal view. – 22. Peristomal view.– 23–26. Holotype of Foveolaria globosa n. sp., GBA 2017/001/0005, all ×4. – 23. Dorsal view. – 24. Apical view. – 25. Basal view. – 26. Peristomal view. – 27–29. Foveolaria sp., GBA 2017/001/0006, all ×4. – 27. Apertural view. – 28. Basal view. – 29. Dorsal view