Identifying and describing fossil thrips (Thysanoptera) sometimes touches the limits of feasibility. Complications handling these tiny fossils are not only caused by their size, their position or fragmentary nature, but also by the state and condition of the matrices surrounding them. Due to poor preservation in some matrices (such as lime, potash and lignite) their identification often remains uncertain (Ulitzka 2015a). Amber, however, considered as a window on times past (Gröhn et al. 2015), presents a wide range of insect inclusions in excellent condition. Nevertheless, many problems can impede our visibility through this 'window'. Fissures, opacity or clouding in the fossil resin, as well as inclusions or bubbles of air, can cover specific characteristics of an included specimen. Curvature of the amber surface results in optical distortions that can impede a reliable assessment of certain features, and the deeper an inclusion is in the amber the greater are the problems. For these reasons cutting or grinding the amber as close as possible to a specimen is essential. In the future, synchrotron X-ray microtomography may be an alternative (Henderickx et al. 2012; van de Kamp et al. 2014), but at present is too complex and expensive.
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http://dx.doi.org/10.11646/zootaxa.4231.4.7 | DOI Listing |
Curr Biol
December 2024
Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
Predation is an important driver of species-level change in modern and fossil ecosystems, often through selection for defensive phenotypes in prey responding to predation pressures over time. Records of changes in shell morphology and injury patterns in biomineralized taxa are ideal for demonstrating such adaptive responses. The rapid increase in diversity and abundance of biomineralizing organisms during the early Cambrian is often attributed to predation and an evolutionary arms race.
View Article and Find Full Text PDFCladistics
December 2024
Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Miguel Lillo 205, CP 4000, San Miguel de Tucumán, Tucumán, Argentina.
The royal ferns (Osmundales) are a morphologically diverse group of leptosporangiate ferns, the fossil record of which dates back to the Permian. Despite there being numerous described permineralized species, the phylogenetic relationships between extinct species remain contentious. Although several analytical approaches have been applied to infer well-resolved phylogenetic hypotheses-even methods that are arguably conceived to be better at dealing with data conflict and uncertainty, many taxa have not been assigned to specific taxonomic categories.
View Article and Find Full Text PDFZoological Lett
December 2024
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Av. dos Estados, 5001. Bairro Bangu, Santo André, SP, 09210-580, Brazil.
Among the insects with wings clad in scales, the butterflies are the best known and those showing greatest variety of scale types. In the Diptera, some families or particular genera of two large groups are known to bear scales on wings, i.e.
View Article and Find Full Text PDFSci Rep
December 2024
Negaunee Integrative Research Center, Field Museum, 1400 S. Dusable Lake Shore Drive, Chicago, IL, 60605, USA.
Enantiornithes are the most successful early-diverging avian clade, their fossils revealing important information regarding the structure of Cretaceous avifaunas and the parallel refinement of flight alongside the ornithuromorph lineage that includes modern birds. The most diverse recognized family of Early Cretaceous enantiornithines is the Bohaiornithidae, known from the Jehol Biota in northeastern China. Members of this clade enhance our understanding of intraclade morphological diversity and elucidate the independent evolution of this unique lineage.
View Article and Find Full Text PDFJ Hum Evol
December 2024
Department of Anthropology, University at Albany (SUNY), 1400 Washington Avenue, Albany, NY 12222, USA; College of Fellows, Institute of Advanced Study, Durham University, Cosin's Hall, Palace Green, Durham, DH1 3RL, UK; Department of Anthropology, Durham University, Dawson Building, South Road, Durham, DH1 3LE, UK. Electronic address:
The degree of sexual size dimorphism in fossil hominins is important evidence for the evaluation of evolutionary hypotheses, but it is also difficult/impossible to measure directly. Multiple methods have been developed to estimate dimorphism in univariate and multivariate datasets, including when data are missing. This paper introduces 'dimorph', an R package that implements many of these methods and associated resampling-based significance tests and evaluates their performance in terms of Type I error rates and power.
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