Teasing Apart Impacts of Human Activity and Regional Drought on Madagascar’s Large Vertebrate Fauna: Insights From New Excavations at Tsimanampesotse and Antsirafaly

Madagascar experienced a major faunal turnover near the end of the first millenium CE that particularly affected terrestrial, large-bodied vertebrate species. Teasing apart the relative impacts of people and climate on this event requires a focus on regional records with good chronological control. These records may document coeval changes in rainfall, faunal composition, and human activities. Here we present new paleontological and paleoclimatological data from southwestern Madagascar, the driest part of the island today. We collected over 1500 subfossil bones from deposits at a coastal site called Antsirafaly and from both flooded and dry cave deposits at Tsimanampesotse National Park. We built a chronology of Late Holocene changes in faunal assemblages based on 65 radiocarbon-dated specimens and subfossil associations. We collected stalagmites primarily within Tsimanampesotse but also at two additional locations in southern Madagascar. These provided information regarding hydroclimate variability over the past 120,000 years. Prior research has supported a primary role for drought (rather than humans) in triggering faunal turnover at Tsimanampesotse. This is based on evidence of: (1) a large freshwater ecosystem west of what is now the hypersaline Lake Tsimanampesotse, which supported freshwater mollusks and waterfowl (including animals that could not survive on resources offered by the hypersaline lake today); (2) abundant now-extinct terrestrial vertebrates; (3) regional decline or disappearance of certain tree species; and (4) scant local human presence. Our new data allow us to document the hydroclimate of the subarid southwest during the Holocene, as well as shifts in faunal composition (including local extirpations, large-vertebrate population collapse, and the appearance of introduced species). These records affirm that climate alone cannot have produced the observed vertebrate turnover in the southwest. Human activity, including the introduction of cattle, as well as associated changes in habitat exploitation, also played an important role.

Molecular-structural homology of proteolytic enzymеs in the studying of proteolysis mechanism and its regulation

The actual problem of experimental medicine is the substantiation of new model organisms that meet modern requirements of bioethics, cost and conditions of detention. The aim of this work was a comparative analysis of the homology degree of proteolytic enzymes in humans and pulmonary freshwater mollusks. The homology of enzymes in nucleotide sequences in humans and pulmonary freshwater mollusks in the analysis of unregulated proteolysis is 66–68 %; regulated proteolysis – 69–76 %; ubiquitin-like modifiers – 78–83 %; extracellular enzymes – 67–76 %; and intracellular enzymes – 65–72 %. The evolutionary conservatism of proteolytic enzymes and the presence of an open blood circulation, which allows the substances under study to be delivered from the hemolymph directly to target cells, make it possible to use these animals as cheap and convenient test organisms. The practical importance of a sufficiently high homology degree of proteolytic enzymes in humans and pulmonary freshwater mollusks justifies the expediency of forming mollusk aquaculture to obtain proteolytic enzyme protein preparations from their tissues within the framework of the tasks of biopharmaceuticals, cosmetics and the food industry.

DYNAMICS OF HORSE INFECTION WITH THE TREMATODE SCHISTOSOMA TURKESTANICUM SKRJABIN, 1913 IN KARAKALPAKSTAN

The dynamics of infection of horses with the trematode Schistosoma turkestanicum Skrjabin, 1913 in Karakalpakstan was studied. We carried out scientific research in various regions of the Republic of Karakalpakstan in 2016–2020. When determining the infection of horses with trematodes in the districts of Karakalpakstan, we used methods of complete and incomplete helminthological dissection by K. I. Skriabin (1928). A total of 143 horses were examined by the complete dissection method. The article presents the results of studies carried out on the territory of the Republic of Karakalpakstan. Helminths were found in all 143 horses examined during the study. The trematode Schistosoma turkestanicum Skrjabin, 1913 was among the identified helminths, which is very common in this region. The parasitic worms Schistosoma turkestanicum were found to belong to the Plathelminthes type, the Trematoda class. The study results indicate that the simultaneous presence of mixed (associative) invasions by trematodes was observed in horses. It was established that trematodes found in horses parasitize on blood vessels of the bile ducts, gallbladder, liver and intestinal mesentery. The prevalence of the trematode Schistosoma turkestanicum in horses was 18.8%, and the intensity of invasion was 3876–12538 specimens. The trematode Schistosoma turkestanicum, depending on the development cycle, develops in the presence of an intermediate host. Freshwater mollusks Lymnaea auricularia, belonging to the family Lymnaeidae perform the function of an intermediate host.

THE SPREAD OF SHEEP FLUKES ON THE ECOLOGICALY DIFFERENT TYPES OF PASTURES IN THE DAGESTAN LOWLAND

The trematodeses (fascioliasis, dicrocoeliosis, paramphistomatosis) are widespread helminthes of sheep. Animals are infected with pathogens of these helminthes on pastures and near water sources. It is established that these trematodoses are common among sheep with different intensity on ecologically different types of pastures of the Dagestan lowland. So, fascioliasis is recorded among sheep on wet lowland with many waterholes, as well as on steppe ecosystems with irrigation and near permanently functioning artesian wells with wetlands with developed freshwater malacofauna. Paramphistomatosis occur in habitats with permanent water sources with the fauna of freshwater mollusks of the family Planorbidae. Dictyocaulosis among sheep is observed in the dry steppe territories with an abundance of land mollusks and ants. Sheep were infected with fascioles in the Dagestan lowlands with an invasion extensity (IE) of 10.0–26.6%, with an invasion intensity (II) of 5–216 copies, with paramphistomum and calicoforum 3.0–15.8% and 4–140 copies, with dicrocelium 18,0–76,6% and 120–2670 copies, respectively. Mixed infestations of trematodoses, strongylatoses, and larval teniidoses are recorded in the interfluve area of Sulak, Terek, Talovka, and Kuma, as well as near the Arakum, Lower Terek, and Shirokolsky reservoirs.

Freshwater mollusks as proxies for assessing agrochemicals hazards in Volta Grande Reservoir, Brazil

Brazil has experienced a rise in the use of agrochemicals in recent years, representing a potential threat to nearby ecosystems. The Volta Grande Reservoir (Minas Gerais/São Paulo, Brazil) has about 87% of its area surrounded by agricultural systems, and many compounds used in agriculture end up being carried into nearby water bodies. Given the potential ecological risk, our purpose was to assess pesticides in the reservoir. We collected specimens of two bivalves and three gastropods using bottom dredging and visual investigation in three different sites within the reservoir. The sampling sites were classified according to their distance from the dam, and all were close to agricultural lands. The samples were processed and frozen for qualitative toxicological analysis using mass spectrophotometry. Eight pesticides were identified, including four organochlorines (Aldrin, p,p’-DDE, Heptachlor epoxide, and Endrin) and organophosphates (Disulfoton, Malathion, Parathion- methyl, and Parathion-ethyl). All five studied species (Limnoperna fortunei, Corbicula fluminea, Melanoides tuberculata, Aylacostoma tenuilabris, and Pomacea aff. canaliculata) presented traces of pesticides in their bodies. Of the eight pesticides found in our analysis, six are illegal in Brazil, raising awareness about the continuous use of forbidden pesticides, and also the ecological risk in the Volta Grande Reservoir area. Our results suggest stricter control by environmental agencies regarding the use and commercialization of these illegal toxic compounds.

A new cheilostome bryozoan from a dinosaur site in the Upper Cretaceous (Campanian) Judith River Formation of Montana

Few bryozoans have been described from the Cretaceous Western Interior Seaway (WIS), which is consistent with the low diversity of other typically stenohaline groups in this large expanse of relatively shallow marine water. Here we describe a new cheilostome bryozoan, Conopeum flumineum n. sp., based on well-preserved material from the Campanian Judith River Formation of the Upper Missouri River Breaks National Monument in north-central Montana. The new species shows strong morphological similarities with Conopeum seurati, a Recent species that is often categorized as brackish, but which is euryhaline and can also be found in marine and stenohaline environments. The new Campanian bryozoan species was found in a locality also containing fragmentary remains of dinosaurs and other terrestrial vertebrates, as well freshwater mollusks and terrestrial plant debris. The sedimentology and facies associations of the fossil-bearing site suggest that the depositional setting was a swamp or tidally influenced fluvial backwater on the Judith River coastal plain. The proximity of the site to the western shoreline of the WIS presumably made it susceptible to occasional marine flooding during storms or extreme tides. Previous occurrences of Conopeum in the Cretaceous of the Western Interior have also been associated with dinosaur remains, corroborating the very nearshore and at times even ‘upstream’ distribution of this euryhaline genus. UUID: http://zoobank.org/bb1fdc8a-5017-44c5-9251-9e24ef3995e3.

A perspective on Plio-Pleistocene hydrosystems of the northern Turkana Depression (East African Rift System) reconstructed from the study of freshwater mollusk communities

<p>The northern Turkana Depression of the East African Rift System in Northern Kenya and Southwestern Ethiopia has one of the most complete and well-documented late Cenozoic continental fossil records worldwide, including remarkable finds of early hominins and associated African Cenozoic vertebrates. Most previous paleoenvironmental reconstructions of the depression were developed using terrestrial vertebrate faunas and paleolandscapes, leaving freshwater ecosystems and associated hydrosystems (lakes, tributaries, river deltas, and wetlands) largely unaddressed. African Cenozoic freshwater mollusks were long considered to be good biostratigraphic indicators, given that their communities are able to represent long phases of morphological stability and at other times rapid morphological changes. However, to what extent changes in freshwater mollusk assemblages match with changes in sedimentary landscapes and lake level fluctuations remains unclear. Here, we address this question through integrative studies on Plio-Pleistocene fossil freshwater mollusks assemblages. Specifically, we are developing a taxonomic framework on fossil freshwater bivalves belonging to the families Unionidae, Iridinidae, Etheriidae and Corbiculidae to create a standardized overview of stratigraphically well-characterized fossil assemblages. Subsequently, we integrate this paleontological dataset with sedimentological characterizations of the depositional environments in which shell beds accumulated at high resolution around faunal turnover events. A detailed reconstruction of environmental changes and how these changes affected freshwater ecosystems in the northern Turkana Depression may allow us to recognize key environmental drivers that triggered faunal turnover events. Such an understanding of drivers from the past perhaps provides our best hope to anticipate how future environmental changes will alter freshwater ecosystems in tropical Africa, and, ultimately, the availability of various freshwater resources on which humanity depends.</p>

Mixed course of Fasciolosis and Paramphistomatosis in sheep in Uzbekistan

The purpose of the research to study the mixed course of sheep infection, caused by pathogens of fasciolosis and paraphistomatosis, in the conditions of Samarkand and Tashkent regions. Materials and methods. The research material was fallen and forcibly killed sheep from two regions of Uzbekistan, simultaneously infected by Fasciola gigantica and Paramphistomum spp. (Gastrothylax crumenifer, Calicophoron calicophorum). The animals' liver was subjected to complete helminthological dissection, followed by the presence of young immature in the parenchyma, and in the bile ducts – sexually mature fasciola. To detect pathogens of paramphistomatosis, we examined the scar and mesh, and, if necessary, the mucous membranes of the abomasum and the initial part of the small intestine. To kill the collected F. gigantica and complete bleeding with a Paramphistomum spp., they were kept in water for one and three to four days, respectively. After they took their natural form, their type, age and number were determined, and then fixed in Barbagallo fluid. If necessary, coprological studies of sheep and malacological studies of biotopes of freshwater mollusks, intermediate hosts of the studied trematodes, were carried out. Results and discussion. In recent years, cases of a mixed course in sheep fasciolosis (F. gigantica) and paramphistomatosis in farms of Uzbekistan have become more frequent. When opening the liver of the fallen sheep, up to 278 specimens were found immature F. gigantica and up to 3994 sp. G. crumenifer. In some farms, the death of individual owners' sheep from calicophorosis caused by C. calicophorum was observed with an intensity of infection of 592 sp. of C. calicophorum.