Search results for "Ammoniti"
showing 4 items of 14 documents
Pseudolillia Maubeuge, 1949 (Ammonitida, Hildoceratidae) in the Lower Jurassic (Toarcian) of the NE Spain
2017
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 o…
Modalités évolutives du genre bullatimorphites (Ammonitina) au Bathonien-Callovien (Jurassique moyen) en Europe occidentale
1999
Abstract The genus Bullatimorphites, (macroconchs Bullatimorphites, Kheraiceras; microconchs Bomburites, Schwandorfia, Spbaeroptycbius, Treptoceras), is characterized by an ontogenesis with three morphologic phases: serpenticone, sphaerocone and ellipticone. Within the successive populations, the relative development of these morphologies allows the defined species to be placed in an evolutive and stratigraphic lineage. The history of the genus comprises five steps: 1) emergence (Early Middle Bathonian), 2) first gradual evolution (Middle-Upper Bathonian), 3) first morphological diversification (Uppermost Bathonian), 4) second gradual evolution, 5) second morphological diversification and e…
Le Toarcien inférieur et moyen du Quercy méridional études stratigraphique, sédimentologique et paléoécologique d’après la nouvelle coupe de Caylus (…
2017
The study of a new section around Caylus (Tarn-et-Garonne) allows new biostratigraphic and sedimentological observations on the terms of passage from the Upper Pliensbachian (Formation of the Barre à Pecten) to the Toarcien (Formation de Penne) of the Quercy (France). The Schistes cartons member (Lower Toarcian, Serpentinum zone) is particularly remarkable.Four taxa of brachiopods and eleven taxa of Toarcian ammonites from the Tenuicostatum, Serpentinum and Bifrons zones, sub-zone to Sublevisoni are the subject of the following paleontological study.
Data from: Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study
2017
In biogeography, the similarity distance decay (SDD) relationship refers to the decrease in compositional similarity between communities with geographical distance. Although representing one of the most widely used relationships in biogeography, a review of the literature reveals that: (1) SDD is influenced by both spatial extent and sample size; (2) the potential effect of the phylogenetic level has yet to be tested; (3) the effect of a marked biogeographical structuring upon SDD patterns is largely unknown; and (4) the SDD relationship is usually explored with modern, mainly terrestrial organisms, whereas fossil taxa are seldom used in that perspective. Using this relationship, we explore…