Changes to the Fossil Record of Insects through Fifteen Years of Discovery

The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and only about ten percent have unchanged ranges. Despite these significant additions to knowledge, the broad pattern of described richness through time remains similar, with described richness increasing steadily through geological history and a shift in dominant taxa, from Palaeoptera and Polyneoptera to Paraneoptera and Holometabola, after the Palaeozoic. However, after detrending, described richness is not well correlated with the earlier datasets, indicating significant changes in shorter-term patterns. There is reduced Palaeozoic richness, peaking at a different time, and a less pronounced Permian decline. A pronounced Triassic peak and decline is shown, and the plateau from the mid Early Cretaceous to the end of the period remains, albeit at substantially higher richness compared to earlier datasets. Origination and extinction rates are broadly similar to before, with a broad decline in both through time but episodic peaks, including end-Permian turnover. Origination more consistently exceeds extinction compared to previous datasets and exceptions are mainly in the Palaeozoic. These changes suggest that some inferences about causal mechanisms in insect macroevolution are likely to differ as well

Host‐plants of leaf‐miners in Australian subtropical rainforest

Leaf‐miners are endophytic insect herbivores that are considered to be relatively host‐specific compared with other types of insect herbivores, often depending on one or a few congeneric hosts. Because of their degree of host‐specificity, they may be particularly vulnerable to environmental change. Despite this, little is known about the host‐plants and life histories of the Australian leaf‐mining fauna. Here we present new information on the host‐plant use of leaf‐miners occurring in Australian subtropical rainforest. We repeatedly hand‐collected leaf‐miners at 14 sampling sites in the ‘Tweed Caldera’ subtropical rainforest region of south‐eastern Queensland and north‐eastern New South Wales, Australia. Leaf‐miners and their host‐plants were identified to species (or morphospecies in the case of some leaf‐miners). Within the region, a total of 106 plant species was recorded as leaf‐miner hosts, on which a total of 12 679 individual leaf‐miners was counted, belonging to 50 different species. We measured the local host‐plant range of each leaf‐miner species for which we had reliable incidence records across sampling sites (24 species). Local host‐specificity was relatively high with 66.7 % of species recorded from a single or two congeneric host‐plants. 16.7 % of species were restricted to a single plant family and 16.7 % were recorded on a few to several plants of the same plant order or across a range of unrelated host‐plants

Imaging of Jurassic fossils from the Talbragar Fish Bed using fluorescence, photoluminescence, and elemental and mineralogical mapping

<div><p>The Talbragar Fish Bed is one of Australia’s most important Jurassic deposits for freshwater fishes, land plants and aquatic and terrestrial insects. The site has yielded many well preserved fossils, which has led to the formal description of numerous new species and higher taxa. The excellent preservation of many fossils has allowed detailed anatomical studies, e.g. of the early teleost fish <i>Cavenderichthys talbragarensis</i> (Woodward, 1895). Here we report on the fluorescent characteristics and mineral composition of a range of Talbragar fossils. Most specimens fluoresce under ultraviolet, blue and green light. Elemental and mineralogical analyses revealed that the Talbragar fossils consist predominantly of quartz (SiO₂), a mineral that is likely to account for the observed fluorescence, with trace kaolinite (Al₂Si₂O₅(OH)₄) in some of the fish fossils. Rock matrices are predominantly composed of quartz and goethite (FeO(OH)). Closer inspection of a plant leaf (<i>Pentoxylon australicum</i> White, 1981) establishes fluorescence as a useful tool for the visualisation of anatomical details that are difficult to see under normal light conditions.</p></div