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

The nymph of Callibaetis dominguezi Gillies (Ephemeroptera: Baetidae)

Callibaetis dominguezi Gillies was described based on male and female imagines from the northwest of Argentina. Herein the nymph of this species is described for the first time. It can be distinguished from other species in the genus mainly by (1) distal margin of labrum with deep median emargination; (2) maxillary palp almost two times the length of galea-lacinia; (3) abdomen with segments I–X with a reddish brown spot along midline. Diagnoses for male and female imagines are emended after studying specimens reared from nymphs. In males the distal 1/3 of the forewings is pigmented while in females the costal and subcostal areas are brown; this character is unique for this species.Callibaetis dominguezi Gillies fue descripta a partir de machos y hembras del Noroeste de Argentina. Aquí la ninfa de esta especie se describe por primera vez. Se puede distinguir de las otras especies del género principalmente por (1) el margen distal del labro con una profunda emarginación media; (2) palpo maxilar casi dos veces el largo de la galea-lacinia; (3) abdomen con los segmentos I–X con una mancha castaña rojiza alargada en la línea media. Las diagnosis para los machos y las hembras adultas están mejoradas después de estudiar los especimenes criados a partir de las ninfas. En los machos el tercio distal de las alas anteriores está pigmentado mientras que en las hembras las áreas costal y subcostal son castañas, este carácter es único para esta especie.Fil: Nieto Peñalver, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Cs.naturales E Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Cruz, Paulo Vilela. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; Brasi