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Monday, July 1st, 2024
| Time | Event | ||||
| 12:06p | [PaleoMammalogy • 2024] Temporal Dynamics of Woolly Mammoth Genome Erosion prior to Extinction
Highlights: • Analysis of long-term genomic changes using 21 high-coverage woolly mammoth genomes • Severe bottleneck of the last surviving population when Wrangel Island was isolated • The population partially recovered within a few generations and then remained stable • Inbreeding depression and purging persisted for thousands of years after the recovery Summary: A number of species have recently recovered from near-extinction. Although these species have avoided the immediate extinction threat, their long-term viability remains precarious due to the potential genetic consequences of population declines, which are poorly understood on a timescale beyond a few generations. Woolly mammoths (Mammuthus primigenius) became isolated on Wrangel Island around 10,000 years ago and persisted for over 200 generations before becoming extinct around 4,000 years ago. To study the evolutionary processes leading up to the mammoths’ extinction, we analyzed 21 Siberian woolly mammoth genomes. Our results show that the population recovered quickly from a severe bottleneck and remained demographically stable during the ensuing six millennia. We find that mildly deleterious mutations gradually accumulated, whereas highly deleterious mutations were purged, suggesting ongoing inbreeding depression that lasted for hundreds of generations. The time-lag between demographic and genetic recovery has wide-ranging implications for conservation management of recently bottlenecked populations. Keywords: Mammuthus primigenius, woolly mammoth, extinction, ancient DNA, paleogenomics, mutation load, inbreeding, bottleneck, climate, Wrangel Island
M. Dehasque, H. E. Morales, et al. 2024. Temporal Dynamics of Woolly Mammoth Genome Erosion prior to Extinction. Cell. DOI: 10.1016/j.cell.2024.05.033 New genetic study reveals the woolly mammoths' journey towards extinction  | ||||
| 12:58p | [PaleoMammalogy • 2024] New insights on the Ecology and Behavior of Machairodus aphanistus (Carnivora: Felidae: Machairodontinae) through the Paleopathological Study of the Fossil Sample from the Late Miocene (Vallesian, MN 10) of Cerro de los Batallones
Abstract The Late Miocene natural traps of Cerro de los Batallones (Madrid, Spain) have yielded thousands of fossils of vertebrates, mostly carnivoran mammals such as hyaenids, amphicyonids, ailurids, mustelids, ursids, and felids, especially Batallones-1 and Batallones-3. Among these carnivorans, the tiger-sized saber-toothed felid Machairodus aphanistus was the top predator of the association, and one of the most abundant taxa, represented by thousands of fossils, including several examples of bone pathologies that have never been studied. In this work, we carry out a paleopathological analysis of some of these pathologies from the Batallones sample of this large early machairodontine, with a description of the pathological changes that occurred in the affected bones, a possible diagnosis, and the ethological and ecological consequences of the presence of these diseases in the living animal. The pathological sample of M. aphanistus studied here included a calcaneus and a Mc III from Batallones-1, and a mandible from Batallones-3. The fossils were X-rayed, and their pathologies were described and compared to non-pathological bones. The calcaneus showed a bone callus indicative of osteitis/osteomyelitis or a tumor; the mandible had evidence of the development of an abscess located in the left mandibular body; and the Mc III shows a marked osteosclerosis. These injuries affected the hunting ability of these individuals and gradually weakened them, very likely contributing to their final entrapment in the Batallones cavities, where they were attracted by the presence of previously trapped animals. Keywords: Bone pathology, Cenozoic, Felidae, Paleontology
Manuel J. Salesa, Bárbara Hernández, Pilar Marín, Gema Siliceo, Irene Martínez, Mauricio Antón, María Isabel García-Real, Juan Francisco Pastor and Rosa Ana García-Fernández. 2024. New insights on the Ecology and Behavior of Machairodus aphanistus (Carnivora, Felidae, Machairodontinae) through the Paleopathological Study of the Fossil Sample from the Late Miocene (Vallesian, MN 10) of Cerro de los Batallones (Torrejón de Velasco, Madrid, Spain). Journal of Mammalian Evolution. 31, 21. DOI: 10.1007/s10914-024-09721-8  | ||||
| 1:23p | [Herpetology • 2024] Trimeresurus cyanolabris • A New Species of Green Pitviper of the Trimeresurus macrops complex (Serpentes: Viperidae) from South Central Coastal Region of Vietnam
Abstract We describe a new species of green pitviper from southern and central parts of coastal Vietnam based on morphological and molecular (2406 bp from cyt b, ND4, and 16S rRNA mitochondrial DNA genes) lines of evidence. Trimeresurus cyanolabris sp. nov. is distinguished from its congeners by the combination of the following morphological characters: small size, maximum known SVL of 638 mm; dorsal scales in 21 (rarely 23)–21–15 rows, moderately keeled except the outermost rows; ventral scales 166–178; subcaudal scales 52–75, all paired; hemipenis forked, calyculate, reaching the 8th subcaudal; eye bright yellow in both sexes; dorsal surface deep green lacking cross-bands; postocular white stripe missing in both sexes; ventrolateral stripe faintly present on the first few dorsal scale rows in males, absent in females; throat, chin, and lower labials in shades of blue. The new species forms a distinct clade on the phylogenetic tree of the genus Trimeresurus and differs from the morphologically similar T. rubeus by a significant divergence in cytochrome b mitochondrial DNA gene sequences (p = 6.0%). The new species is currently known from low- to mid-elevations (ca. 90–400 m a.s.l.) in tropical forests of central-southern Vietnam. This discovery further underlines the importance of this area as a local center of herpetofaunal diversity and endemism, which is under great threat of deforestation. Reptilia, Trimeresurus cyanolabris sp. nov., Vietnam, new species, morphology, molecular phylogeny, systematics   Rắn lục mép xanh dương Trimeresurus cyanolabris     Sabira S. Idiiatullina, Tan Van Nguyen, Andrey M. Bragin, Parinya Pawangkhanant, Dac Xuan Le, Gernot Vogel, Patrick David and Nikolay A. Poyarkov. 2024. A New Species of Green Pitviper of the Trimeresurus macrops complex (Reptilia: Serpentes: Viperidae) from South Central Coastal Region of Vietnam. Zootaxa. 5474(4); 375-411. DOI: doi.org/10.11646/zootaxa.5474.4.3 facebook.com/groups/siasr/permalink/7931 facebook.com/100088301342746/posts/44148 |
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