A review of the Hirmeriellaceae (Cheirolepidiaceae) wood

International audienceSummary The Hirmeriellaceae are an extinct family of Mesozoic conifers. Their foliage has been described in the genera Brachyphyllum , Frenelopsis , Pseudofrenelopsis , etc., while their pollen corresponds to the genus Classopollis , the male cones to e.g. Classostrobus or Tomaxellia and the female scales were named Hirmeriella and Paraucaria , for example. Reproductive structures are necessary for a definite identification of the family. Such fossils are rarely found in connection with mature secondary xylem. As a result, very little is known about the wood anatomy of the Hirmeriellaceae. This work reviews available evidences, either from connections between wood and reproductive structures typical for the Hirmeriellaceae or from associations of such fossils within Mesozoic rocks. Connection cases are rare and are reported only for the Cretaceous and for genera Frenelopsis and Pseudofrenelopsis . Association cases are more numerous; however, they are also poorly distributed in time, being reported mostly from two intervals only, the latest Triassic–earliest Jurassic and the Early Cretaceous. Wood data are also poorly distributed taxonomically with most of them being from the frenelopsids. The fossil genera Agathoxylon , Brachyoxylon , Protocupressinoxylon and Protopodocarpoxylon were used for wood fossils which are more or less safely related to the Hirmeriellaceae. However, only the first two seem to have been rightly used, the first usually for juvenile or small diameter wood, the second for more mature wood. Even if there seems to be a privileged link between Brachyoxylon and the Hirmeriellaceae, it cannot be said to be exclusive

The Cenomanian amber of Fourtou (Aude, Southern France): Taphonomy and palaeoecological implications

International audienceThe discovery of new amber outcrops in France in the last fifteen years and the reinvestigation of outcrops that had been forgotten provide new sources of palaeontological data. One of these forgotten localities is the Cenomanian outcrop of Fourtou in the Aude department, Southern France. Mentioned in old manuscripts since 1700, perhaps known and used since the Palaeolithic, the Cenomanian amber of Aude is still poorly studied. Here we present a synthesis of the data obtained on this amber, focusing on the outcrop of Fourtou that provided the largest quantity of amber in the area. Systematic and taphonomy of Fourtou amber inclusions are described and discussed in order to propose a hypothesis about the environment in which Cenomanian Fourtou amber was produced

A Jurassic amber deposit in Southern Thailand

International audiencePublished reports of amber predating the Aptian are rare and mention only amber pieces the size of millimetric marbles. Mid Cretaceous amber records, however, show a dramatic increase in number as well as in the size of the pieces, a phenomenon which is still poorly understood. The discovery of the first Jurassic deposit with comparatively large centimetric sized pieces of amber, in southern Thailand, is significant. Taphonomy and palaeobotany indicate a dense forest surrounding a coastal lake dominated by the resin-producing Agathoxylon tree. Since the palaeoecology of other amber-producing Jurassic and Cretaceous deposits is very similar a new hypothesis needs to be sought to explain the mid Cretaceous amber boom. It is suggested here that it was the result of a geological or taphonomic bias because coastal lacustrine environments are much better preserved after the Aptian on a worldwide scale