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RESEARCH PRODUCT

Pseudolillia Maubeuge, 1949 (Ammonitida, Hildoceratidae) in the Lower Jurassic (Toarcian) of the NE Spain

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In the present paper, 147 specimens assigned to the genus Pseudolillia Maubeuge, 1949 are studied. This is a considerably high number of samples in comparison with those known in other geographical areas where they have been cited, such as northern France, the Pyrenees, the Betic Range, Morocco, Portugal, Italy, Hungary and Bulgaria. The six taxa described, P. murvillensis, P. hispanica, P. emiliana, P. donovani, Pseudolillia ? n. sp. (en García-Gómez & Rivas, 1980), and Pseudolillia ? sp., come from 22 sites in the Cantabrian and Iberian Ranges and the Isle of Majorca. Their presence in expanded sections enabled us to situate the stratigraphic position of the genus between the upper part of the Thouarsense Chronozone (Fallaciosum Subchronozone) to the Dispansum Chronozone (Gruneri Subchronozone), with maximum abundance found in the Dispansum Chronozone (Insigne Subchronozone). The origin of the genus is unclear, and a possible derivation from the last representatives of Grammoceras (close to G. striatulum) or more likely from Esericeras (close to E. fascigerum) has been suggested. The known palaeobiogeographic range of Pseudolillia is limited to the NW-European Province and to the W of the Tethys, and with the exception of P. emiliana, the species’ distribution ranges are short. In NE Spain, where the highest number of known specimens comes from, P. donovani (typical of the Mediterranean province) is the species presenting the oldest record (Chronozone Thouarsense, Subchronozone Fallaciosum), although it did not necessarily live and reproduce in very nearby areas. P. murvillensis (typical of the NW-European Province), was found in the Chronozone Dispansum (Subchronozone Insigne) together with P. emiliana and P. hispanica in the eastern Pyrenees and particularly in the central sector of the Iberian Range.