The discovery of exotic species in a typical Mediterranean Toarcian region is unusual. We report the discovery of two NW European species of Grammoceratinae from the Toarcian Rosso Ammonitico Umbro-Marchigiano Formation: Pseudolillia donovani Garcia-Gomez & Rivas, 1980 and Phlyseogrammoceras cf. dispansum (Lycett, 1860). P. donovani was found in the Scoppio section, Martani Mountains, in Umbria, at the base of a slump without accompanying fauna; above, the slump contains reworked specimens of Geczyceras cf. speciosum (Janensch, 1902). P. donovani is one of the earliest species of the genus, having been found in the Fallaciosum Subzone of the Thouarsense Zone (upper Bonarellii Zone of the Mediterranean province), and is widespread from a paleobiogeographical point of view, having been found in South-Eastern France, and the Betic and Iberian Cordilleras. P. cf. dispansum was discovered at Val Tenetra, Monte Catria group, Marche, as an ex situ specimen; P. dispansum is typical of the Pachu biohorizon of the Dispansum Zone of the NW European province. It is abundant in France, Germany, Luxembourg, and England, and is also recorded from Portugal, Bulgaria, the Caucasus and Iran. It should be noted that in the Thouarsense Zone, Sassaroli & Venturi (2005) reported the new species Pseudolillia apenninica, and Venturi et al. (2010) cited Grammoceras sp. At the top of the Speciosum Zone, in the Scoppio section, numerous specimens of Gruneria cf. gruneri (Dumortier, 1874) were found. It seems that in the Thouarsense and Speciosum Chrons, the Grammoceratinae were able to migrate towards the south, with rare, drifted specimens or ephemeral populations, possibly linked to changes in currents, sea level or climate in the Late Toarcian.

New findings of Grammoceratinae (Ammonitina: Hildoceratidae) from the Toarcian of the Central Apennines (Central Italy)

Pignatti Johannes
2022

Abstract

The discovery of exotic species in a typical Mediterranean Toarcian region is unusual. We report the discovery of two NW European species of Grammoceratinae from the Toarcian Rosso Ammonitico Umbro-Marchigiano Formation: Pseudolillia donovani Garcia-Gomez & Rivas, 1980 and Phlyseogrammoceras cf. dispansum (Lycett, 1860). P. donovani was found in the Scoppio section, Martani Mountains, in Umbria, at the base of a slump without accompanying fauna; above, the slump contains reworked specimens of Geczyceras cf. speciosum (Janensch, 1902). P. donovani is one of the earliest species of the genus, having been found in the Fallaciosum Subzone of the Thouarsense Zone (upper Bonarellii Zone of the Mediterranean province), and is widespread from a paleobiogeographical point of view, having been found in South-Eastern France, and the Betic and Iberian Cordilleras. P. cf. dispansum was discovered at Val Tenetra, Monte Catria group, Marche, as an ex situ specimen; P. dispansum is typical of the Pachu biohorizon of the Dispansum Zone of the NW European province. It is abundant in France, Germany, Luxembourg, and England, and is also recorded from Portugal, Bulgaria, the Caucasus and Iran. It should be noted that in the Thouarsense Zone, Sassaroli & Venturi (2005) reported the new species Pseudolillia apenninica, and Venturi et al. (2010) cited Grammoceras sp. At the top of the Speciosum Zone, in the Scoppio section, numerous specimens of Gruneria cf. gruneri (Dumortier, 1874) were found. It seems that in the Thouarsense and Speciosum Chrons, the Grammoceratinae were able to migrate towards the south, with rare, drifted specimens or ephemeral populations, possibly linked to changes in currents, sea level or climate in the Late Toarcian.
978-615-5270-71-0
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11573/1652500
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