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Thursday, December 8th, 2022
| Time | Event | ||
| 4:36a | [Entomology • 2022] Calvisia (Calvisia) khlongsokana • A New Species of Calvisia (Phasmida: Lonchodidae: Necrosciinae) from Thailand and Myanmar and Notes on C. (Calvisia) sangarius from Peninsular Malaysia
A colourful new species of Calvisia Stål, 1875, Calvisia (Calvisia) khlongsokana sp. nov., is described from Southwest Thailand and South Myanmar based on both sexes, nymphs and eggs. The new species is placed in the subgenus C. (Calvisia) Stål, 1875 and compared to the closely related species C. (Calvisia) sangarius (Westwood, 1859). The female of C. (Calvisia) sangarius (Westwood, 1859) and both sexes and egg of C. (Calvisia) khlongsokana sp. nov. are illustrated and a distribution map for both species is provided. Females of the new species occur in two distinct colour forms presumed to be aposematic. Several hypotheses are provided for the natural occurrence of these two morphs with frequency-dependant selection as a possible driver. Keywords: Stick insect, Phasmatodea, aposematism, sexual dichromatism, sex-limited polymorphism.      Joachim Bresseel, Jérôme Constant, Kawin Jiaranaisakul and Christian Hübner. 2022. A New Species of Calvisia (Calvisia) from Thailand and Myanmar and Notes on C. (Calvisia) sangarius from Peninsular Malaysia (Phasmida, Lonchodidae, Necrosciinae). Belgian Journal of Entomology. 133:1-23.  | ||
| 12:37p | [Paleontology • 2022] Zuul crurivastator • Palaeopathological Evidence for Intraspecific Combat in Ankylosaurid Dinosaurs
Abstract Ankylosaurid dinosaurs were heavily armoured herbivores with tails modified into club-like weapons. These tail clubs have widely been considered defensive adaptations wielded against predatory theropod dinosaurs. Here we argue instead that ankylosaurid tail clubs were sexually selected structures used primarily for intraspecific combat. We found pathological osteoderms (armour plates) in the holotype specimen of Zuul crurivastator, which are localized to the flanks in the hip region rather than distributed randomly across the body, consistent with injuries inflicted by lateral tail-swinging and ritualized combat. We failed to find convincing evidence for predation as a key selective pressure in the evolution of the tail club. High variation in tail club size through time, and delayed ontogenetic growth of the tail club further support the sexual selection hypothesis. There is little doubt that the tail club could have been used in defence when needed, but our results suggest that sexual selection drove the evolution of this impressive weapon. This changes the prevailing view of ankylosaurs, suggesting they were behaviorally complex animals that likely engaged in ritualized combat for social dominance as in other ornithischian dinosaurs and mammals. Keywords: Dinosauria, Ankylosauria, sexual selection, animal weaponry     Victoria M. Arbour, Lindsay E. Zanno and David C. Evans. 2022. Palaeopathological Evidence for Intraspecific Combat in Ankylosaurid Dinosaurs. Biol. Lett. 18: 20220404. DOI: 10.1098/rsbl.2022.0404 | ||
| 5:13p | [Paleontology • 2022] A 2-Million-year-old Ecosystem in Greenland uncovered by environmental DNA
Abstract Late Pliocene and Early Pleistocene epochs 3.6 to 0.8 million years ago had climates resembling those forecasted under future warming. Palaeoclimatic records show strong polar amplification with mean annual temperatures of 11–19 °C above contemporary values. The biological communities inhabiting the Arctic during this time remain poorly known because fossils are rare5. Here we report an ancient environmental DNA6 (eDNA) record describing the rich plant and animal assemblages of the Kap København Formation in North Greenland, dated to around two million years ago. The record shows an open boreal forest ecosystem with mixed vegetation of poplar, birch and thuja trees, as well as a variety of Arctic and boreal shrubs and herbs, many of which had not previously been detected at the site from macrofossil and pollen records. The DNA record confirms the presence of hare and mitochondrial DNA from animals including mastodons, reindeer, rodents and geese, all ancestral to their present-day and late Pleistocene relatives. The presence of marine species including horseshoe crab and green algae support a warmer climate than today. The reconstructed ecosystem has no modern analogue. The survival of such ancient eDNA probably relates to its binding to mineral surfaces. Our findings open new areas of genetic research, demonstrating that it is possible to track the ecology and evolution of biological communities from two million years ago using ancient eDNA.  Kurt H. Kjær, Mikkel Winther Pedersen, Bianca De Sanctis, Binia De Cahsan, Thorfinn S. Korneliussen, Christian S. Michelsen, Karina K. Sand, Stanislav Jelavić, Anthony H. Ruter, Astrid M. A. Schmidt, Kristian K. Kjeldsen, Alexey S. Tesakov, Ian Snowball, John C. Gosse, Inger G. Alsos, Yucheng Wang, Christoph Dockter, Magnus Rasmussen, Morten E. Jørgensen, Birgitte Skadhauge, Ana Prohaska, Jeppe Å. Kristensen, Morten Bjerager, Morten E. Allentoft, Eric Coissac, PhyloNorway Consortium, Alexandra Rouillard, Alexandra Simakova, Antonio Fernandez-Guerra, Chris Bowler, Marc Macias-Fauria, Lasse Vinner, John J. Welch, Alan J. Hidy, Martin Sikora, Matthew J. Collins, Richard Durbin, Nicolaj K. Larsen and Eske Willerslev. 2022. A 2-Million-year-old Ecosystem in Greenland uncovered by environmental DNA. Nature. 612; 283–291. DOI: 10.1038/s41586-022-05453-y https://phys.org/news/2022-12-disco  The lost world: The cover shows an artist’s impression of the rich ecosystem that existed in parts of northern Greenland some 2 million years ago. The ecosystem is reconstructed from ancient DNA in this week’s issue by Eske Willerslev and colleagues. Working at the Kap København Formation in Peary Land, the researchers gathered sediment samples rich in organic material from 5 different geological sites. By extracting and sequencing DNA from these samples, they were able to piece together a picture of the flora and fauna present around 2 million years ago. The team found evidence of open boreal forest mixed with Arctic species such as cedar, spruce and birch, as well as signs of animals including hares, mastodons, reindeer and geese. The evidence affirms that this part of Greenland, now a polar desert, was 11–17 °C warmer than it is today and suggests it was home to an ecosystem composition that no longer exists anywhere in the world. — Cover image: Beth Zaiken/bethzaiken.com twitter.com/BZaiken |
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