Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 19. 2001. (Budapest, 2001)

Superfamily PNeritoidea RAFINESQUE, 1815 Family PNeritidae RAFINESQUE, 1815 Genus ?A4arntolatella KJTTL, 1894 Marmolatella? sp. (Plate 1:1-4) Material — A single inner mould. Measurements. H HL HP D WP AA AL *29 27.5 26 51 *40 Description — Inner mould of large, neritiformauriform shell. Preserved part little longer than last whorl, beeing evenly convex in beginning, but more convex at periphery near peristome. Shape suggests presence of wide, slighdy convex, ramp-like surface on last half whorl. Low, wide spiral ridge visible on base. Peristome, as well as growth lines on early whorl part and on base, strongly prosocline, prosocyrt and almost tangential to penultimate whorl. Egg-shaped peristome, narrowing towards early shell part. Little above periphery, outer lip seems to bear shallow, wide sinus that is also reflected in the scarcely preserved growth lines on the surface of the initial part of last whorl. Remarks — Auriform marine gastropods are quite common in the Triassic and post-Jurassic Neritoidea. From the Triassic genera with this shape, only Marmolatella (Neritopsidae, Naticopsinae) has already been doubtlessly found in the Jurassic (CONTI & FISCHER 1984), just in the Mediterranean Faunal Province. Some species of Marmolatella have shallow sinus on the outer lip. Another sinus-bearing neritoidean genus is the neritid Neritoma MORRIS, 1849. However, this genus has a narrow and relatively deep sinus and a globular shape therefore the Gerecse find less probably belongs to this genus. The trochoidean Stomatellidae (Triassic—Recent) is also composed of auriform genera, one of which, Mesogena, has already been found (GRECO 1899, WENDT 1972) in the Mediterranean Jurassic, but sinus bearing form has not been reported from any locality. However, because of the poor preservation, belonging to Mesogena cannot be excluded completely. Distribution — "Crocodile" section (NagyPisznice), Toarcian (Variabilis Zone). Superfamily PLittorinoidea GRAY, 1840 Family Purpurinidae ZlTTEL, 1895 There are two similarly shaped species in the material that have low littoriniform shape with narrow, almost horizontal ramp below the suture. The shape of the available inner moulds permits to range them to a wide choice of genera of different families, being not closely related. The (nearly) contemporaneous ones are: Purpurinidae (Tretospira KOKEN, 1892; Angularia KOKEN, 1892; Purpuroidea LYCETT, 1848; Purpurina D'ORBIGNY, 1850), Naticidae [(Globulariinae), Ampullospira HARRIS, 1897; Pictavia COSSMANN, 1925] or Pseudamauridae [(CerithioideaP), Pseudamaura P. FISCHER, 1885]. Some of these genera may be synonymous. The way to find the most probable systematic place is the same in case of both Gerecse species, therefore it will be sketched here separately from the detailed descriptions. Purpurina has strong collabral ridges in the shell sculpture that may cause also undulation of the inner shell surface, but its spiral ornament is not reflected on inner mould. The absence of collabral undulations, but presence of traces of spiral ornament on the available specimens suggest therefore belonging to other genus. Purpuroidea has also strong collabrals and/or nodes along ramp angulation and also spiral ornamental elements that may be reflected on inner shell surface. The trace of the characteristic siphonal outlet, i. e. a backward truncation of the peristome at the foot of columella, which is present in most Purpuroidea species, also provides a really good tool also for distinction of steinkerns. One of the specimens (see below as Purpuroidea? sp.) has traces of spiral cords or angulations and the siphonal notch. Angularia and its subgenera have rather turriculate spire and distinctly protruding siphonal oudet but these characters are not present on the Gerecse specimens. Tretospira is smooth or some species have few spiral cords and/or weak, additional angulation(s) below the ramp. Shell truncation or protrusion at the siphonal outlet are unknown. The other species is probably member of this genus (Tretospira? sp.) Other possible systematic place for the latter species could be Globulariinae {Ampullospira, Pictavià) and Pseudamauridae (Pseudamaura), in which the siphonal truncation or protrusion is lacking. (Pseudamaura is also member of Naticidae in earlier systematics, recendy KOWALKE & BANDEL (1996) have removed it into an independent family of doubtful Cerithioidean position.] However, these genera are usually without any spiral ornament or have only fine lineation or threads that are not reflected on inner shell surface. Therefore the Gerecse specimens, having distinct traces of spiral keels or cords, probably do not belong to these families.