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Thanks to an international research collaboration involving the University of Granada (UGR), a previously undescribed species of insect has been discovered: Calliarcys antiquus.
Belonging to the species of mayflies, Arnold Staniczek of Stuttgart's State Museum of Natural History discovered the species, which was embedded in a chunk of Baltic amber thought to be between 35 and 47 million years old.
The insect was able to be thoroughly examined and identified thanks to the expertise of Professor Javier Alba-Tercedor of the UGR's Department of Zoology, who used microtomography to produce clear photographs of the insect.
The findings were published in Scientific Reports on September 8.
"The conservation of the specimens trapped inside the amber is often excellent, and the transparency of the material that surrounds them enables them to be studied, under a microscope, in great detail," explains Professor Alba-Tercedor in the statement, referring to the newly found insect's discovery.
Javier Alba-Tercedor et al.
"But, in other cases, the level of transparency is not good because the areas of opacity that form preventing certain details from being examined," comments Alba-Tercedor.
When limited transparency is a problem, X-ray microtomography (a technique similar to that used in hospitals to study patients' organs) is invaluable in studying amber-preserved fossil specimens.
Compared to other species
The previously undescribed species of mayfly was then studied by comparing it to extant species of the genus thanks to the expert knowledge of Roman Godunko of the Institute of Entomology of the Czech Academy of Sciences. In addition, given the importance of molecular studies in characterizing species and determining their evolutionary position, the University of Lodz in Poland was also consulted.
Finally, Michal Grabowski and Tomasz Rewicz's team concluded their investigation by analyzing the DNA of the genus' living animals.
"In short, it all started with the discovery of a beautiful insect preserved in amber, which attracted the attention of the expert eyes of a scientist. And this ultimately required the enthusiastic collaboration and detective work of five scientists based in research centers located in four countries, who, after applying the latest techniques, were finally able to name and describe an insect that has remained locked inside a drop of amber for millions of years," says Professor Alba-Tercedor.
Abstract:
Mayflies (Ephemeroptera) are among the oldest pterygote insects, with the earliest fossils dating back to the Late Carboniferous. Within mayflies, Leptophlebiidae are a highly diverse and widespread group, with approximately 140 genera and 640 species. Whereas taxonomy, systematics, and phylogeny of extant Leptophlebiidae are in the focus of extensive studies, little is known about leptophlebiid fossil taxa. Because fossil remains of Ephemeroptera in sedimentary rocks are relatively rare, inclusions of mayflies in amber are a unique source of information on their evolution and diversity in the past. Leptophlebiidae found in Cenozoic resins mostly belong to the subfamilies Leptophlebiinae (in Eocene Baltic amber) and Atalophlebiinae (in Miocene Dominican and Mexican ambers). In the present contribution, we confirm the first finding of the genus Calliarcys from Eocene Baltic amber by using Micro-CT, which allowed confirming its generic placement by visualizing diagnostic key characters otherwise hidden by a cloud of turbidity. Additionally, we present first molecular data on the extant species Calliarcys humilis Eaton, 1881 from the Iberian Peninsula and the barcode gap analysis for Leptophlebiinae and Habrophlebiinae.
