Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 75. (Budapest 1983)
Szabó, J.: Lower and Middle Jurassic Gastropods from the Bakony Mountains (Hungary). Part V.: Supplement to Archaeogastropoda; Caenogastropoda
.Subclass uncertain .Superfamily uncertain Family Mathildidae COSSMANN. 1912 Genus MATHILDA SEMPER Subgenus ITricarüda GRÜNDEL, 1973 Mathilda (Tricarilda?) sp. (Plate III: fig. 11) Measurements: H HL HA D W A Plate 111: fig. 11. — — — 3 — 36 5 Material — One unpreparable and an other, relatively well-preserved specimen (this latter is the figured one). Shape — Dextral, small shell with high spire. The whorls are convex, tricarinate initially and bicarinate later. The uppermost carina is represented on the last whorl as only a hardly visible line. The basis is convex, anomphalous. The embryonal shell and the peristome are unknown. Ornament — Beyond the carinae, secondary spiral lines appear also during growth: one between the two lower carinae on the preserved sixth whorl, one in the narrow zone between the uppermost carina and the suture on the third whorl — this disappears on the penultimate whorl, three between the two uppermost carinae, one on the third whorl, and two on the fifth whorl. The base is covered with spiral threads of which some on the marginal part are similar to the carinae, in strength. The transverse ornament results from periodically repeated threads, which are parallel to the fine, slightly opisthocyrt growth lines. The threads are represented on the base, too. but here these are substantially weaker. The style of the sculpture is cancellate. and in the intersections tiny tubercles appear commonly. Distribution — Bakony Mts., Somhegy: condensed Subfurcatum and Garantiana Zones. Remarks — Suggesting the arrangement of Mathildidae into the superfamily Pyramidellacea (Subclassis Opisthobranchia) KNIGHT et al. (1960) made the higher systematic position of this family uncertain. Similarly uncertain is the subgeneric arrangement of this form based on the number of the spiral carinae (GRÜNDEL 1973): of the three initial carinae ("Primärspiralen") the uppermost one disappears almost completely till the last whorl. Most similar of the published species is that described by WALTHER (1951) under the name Promathilda euglypha (Laube). However, the indentification of this bicarinate form seems wrong, because the species of LAUBE (1867) is pagodiform, i.e. unicarinate. The bad state of preservation of the available specimens makes the clearing up of the satisfactory indentification impossible. % • % With this contribution, the systematic treatment of the faumans of the localities listed in Part I. of this series (v. 71., same journal) is nearing completion. The 85-90 percent of the species have already been treated, the remaining part represents such strongly fragmentary species which were not indentifiable but recognizable as independent units. The writer hopes he can in the near future revisit the problems left open, by examining newly collected materialis and some museum collections. *** Acknowledgements — I am thankful to Professor DR. BARNABÁS GÉCZY (Eötvös Loránd University. Dept. Palaeontology, Budapest) and DR. JÓZSEF KONDA (Hungarian Geological Institute, Budapest), who made possible the studying of the material on which my work is mainly based. I am indebted to Dr. ANDRÁS GALÁCZ (Eötvös Loránd University, Dept. Palaentology. Budapest), who not only translated Part F, II. and V. of this series, but also critically read the papers.
