In this paper we show the results of a paleomagnetic study carried out along the western Andes of central Chile from 30° to 36°S. Whereas paleomagnetic analysis from Jurassic to Late Cretaceous rocks in the Pampean flat slab segment shows small or non significant clockwise vertical-axis rotations, results obtained in Late Jurassic to Neogeone rocks to the south, on the normal subduction segment...

One of the most intensively examined and abundantly documented structures in the animal world is insect mouthparts. Major structural types of extant insect mouthparts are extensive, consisting of diverse variations in element structure within each of the five mouthpart regions•labrum, hypopharynx, mandibles, maxillae, and labium. Numerous instances of multielement fusion both within and among m...

Well-preserved cranial remains of a small sphenodontian lepidosaur from the Upper Triassic Caturrita Formation of Rio Grande do Sul, Brazil, are the first record of the genus Clevosaurus Swinton, 1939 from South America. They represent a new species, Clevosaurus brasiliensis, which is distinguished by a very short antorbital region of the skull (corresponding to about 20 per cent of skull lengt...

Current characterizations of early dinosaur evolution are incomplete: existing palaeobiological and phylogenetic scenarios are based on a fossil record dominated by saurischians and the implications of the early ornithischian record are often overlooked. Moreover, the timings of deep phylogenetic divergences within Dinosauria are poorly constrained owing to the absence of a rigorous chronostrat...

Morphological similarities indicate that Palaeozoic problematic tubeworms, e.g. tentaculitids, cornulitids, microconchids, trypanoporids, Anticalyptraea, and Tymbochoos, form a monophyletic group. This group may also include hederelloids. Members of this group share affinities with lophophorates and their evolution could have partly been driven by predation. The extinction of Palaeozoic tubewor...

This paper describes and illustrates three newly discovered Late Hettangian ammonite specimens from the “Dorsale calcaire” (Calcareous Range) of the internal units of the Rif (Northern Morocco). Two additional Early Sinemurian ammonite specimens are also studied and all the Early and middle Lower Jurassic ammonites collected earlier in this area and illustrated in the literature are included in...

Growing evidence of morphological diversity in angiosperm flowers, seeds and pollen from the mid Cretaceous and the presence of derived lineages from increasingly older geological deposits both imply that the timing of early angiosperm cladogenesis is older than fossil-based estimates have indicated. An alternative to fossils for calibrating the phylogeny comes from divergence in DNA sequence d...

A new salamandroid salamander, Qinglongtriton gangouensis (gen. et sp. nov.), is named and described based on 46 fossil specimens of juveniles and adults collected from the Upper Jurassic (Oxfordian) Tiaojishan Formation cropping out in Hebei Province, China. The new salamander displays several ontogenetically and taxonomically significant features, most prominently the presence of a toothed pa...

Orbitally controlled, sedimentary cycles of the Newark Supergroup permit palyniferous Late Triassic sections to be calibrated in time. Carnian palynofloras from · the Richmond basin exhibit 2-m.y. fluctuations in the spore/pollen ratio, but taxonomic composition remains stable. Diversity of Norian and Rhaetian palynofloras increases prior to a 60% reduction at the Triassic/Jurassic boundary. Th...