The genetic history of Mayotte and Madagascar cattle breeds mirrors the complex pattern of human exchanges in Western Indian Ocean

Despite their central economic and cultural role, the origin of cattle populations living in Indian Ocean islands still remains poorly documented. Here, we unravel the demographic and adaptive histories of the extant Zebus from the Mayotte and Madagascar islands using high-density SNP genotyping data. We found that these populations are very closely related and both display a predominant indicine ancestry. They diverged in the 16th century at the arrival of European people who transformed the trade network in the area. Their common ancestral cattle population originates from an admixture between an admixed African zebu population and an Indian zebu that occurred around the 12th century at the time of the earliest contacts between human African populations of the Swahili corridor and Austronesian people from Southeast Asia in Comoros and Madagascar. A steep increase of the estimated population sizes from the beginning of the 16th to the 17th century coincides with the expansion of the cattle trade. By carrying out genome scans for recent selection in the two cattle populations from Mayotte and Madagascar, we identified sets of candidate genes involved in biological functions (cancer, skin structure and UV-protection, nervous system and behavior, organ development, metabolism and immune response) broadly representative of the physiological adaptation to tropical conditions. Overall, the origin of the cattle populations from Western Indian Ocean islands mirrors the complex history of human migrations and trade in this area.

Volcaniclastic deposits and sedimentation processes around volcanic ocean islands: the central Azores

Geological histories of volcanic ocean islands can be revealed by the sediments shed by them. Hence there is an interest in studying cores of volcaniclastic sediments that are particularly preserved in the many flat-floored basins lying close to the Azores islands. We analyse four gravity cores collected around the central group of the islands. Three sedimentary facies (F1-F2a, F2b) are recognized based on visual core logging, particle morphometric and geochemical analyses. F1 is clay-rich hemipelagite comprising homogeneous mud with mottled structures from bioturbation. F2a and F2b are both clay-poor volcaniclastic deposits, which are carbonate-rich and carbonate-poor, respectively. More biogenic carbonate in F2a reflects the incorporation of unconsolidated calcareous material from island shelves or bioturbation. Within F2a and F2b we identify deposits emplaced by pyroclastic fallout, primary or secondary turbidity currents by combining multiple information from lithological composition, sedimentary structures, chemical composition of volcanic glass shards and morphometric characteristics of volcanic particles. Primary volcaniclastic sediments were found in all four cores, echoing activity known to have occurred up to historical times on the adjacent islands. These preliminary results suggest that greater details of geological events could be inferred for other volcanic islands by adopting a similar approach to core analysis.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5602176

New intertidal crickets from Comoros and Mascarene islands (Orthoptera: Trigonidiidae: Nemobiinae: Burcini)

Nemobiinae crickets of the tribe Burcini Gorochov, 1986 are described for the first time from the shores of South Western Indian Ocean islands. The new genus Makalapobius n. gen. is proposed to include M. aigrettensis n. gen. n. sp. from Mauritius and M. masihu n. gen. n. sp. from Grande Comore, and the new genus Gabusibius n. gen. to include G. ndzilu n. gen. n. sp. from Anjouan, G. mosi n. gen. n. sp., from Mohéli, and G. dzindzanu n. gen. n. sp. from Mayotte. The species Speonemobius littoreus Vannini & Chelazzi, 1978 from Somalia coast is tentatively placed in the genus Gabusibius n. gen. as G. ? litoreus (Vannini & Chelazzi, 1978) n. gen. n. comb. The songs of G. mosi n. gen. n. sp. and M. aigrettensis n. gen. n. sp. are described. The threats to SWIO Burcini and endemism of Orthoptera from SWIO coastal areas are discussed.

The African Species of Drepanolejeunea Vesiculosa Group with Description of Drepanolejeunea Vanderpoortenii Spec. Nova (Jungermanniopsida) from Madagascar

Drepanolejeunea clavicornis and D. friesii were previously synonymised with D. physaefolia or all of them with D. vesiculosa. In the meantime, Drepanolejeunea vandenberghenii was described from the same species group, as new. In this paper many African specimens are compared with the original descriptions of the above species. Morphological investigations of these and their distributional patterns suggested that the former synonymisation was not justified. In addition, a new, rheophytic species from the same group: Drepanolejeunea vanderpoortenii, is described, as new to science. As a result, from the taxa related to Drepanolejeunea vesiculosa, now six species are recognised from Africa, including its Indian Ocean islands. For these 6 morphotaxa an identification key is provided. The results need confirmation by a future molecular analysis.

Emergence of Chikungunya Virus in Pakistan: What should be done?

Since 10 years, Chikungunya – a virus spread through Aedes spp mosquitoes – has reemerged in Africa, southern and southeastern Asia, and the Indian Ocean Islands.1 In SouthEast Asia, epidemics have been documented in India, Malaysia, Sri Lanka, Myanmar, Thailand, Indonesia, the Philippines, Cambodia, Vietnam, Hong Kong, and Pakistan

Long-distance dispersal of migrant butterflies to the Arctic Ocean islands, with a record of Nymphalis xanthomelas at the northern edge of Novaya Zemlya (76.95°N)

Although migrant butterflies are rare (or sporadically seen) guests on the Arctic Ocean islands, there is a slowly growing dataset on repeated occurrences of these insects in insular tundra and polar deserts. Altogether six long-distance migrant butterfly species were found to cross wide marine barriers north of the Arctic Circle (66.56°N), i.e. Vanessa atalanta, V. cardui, Nymphalis antiopa, N. xanthomelas, Aporia crataegi, and Pieris napi. Migrant individuals of V. cardui discovered on Svalbard (up to 78.27°N in 1978) reflect the farthest dispersal event of butterflies to the Arctic ever reported. Our record of N. xanthomelas at the northern margin of Novaya Zemlya (76.95°N) represents the northernmost finding of this species globally, reflecting the world’s second farthest record of northern poleward immigration of butterflies. This occurrence coincides with an exceptionally warm summer season, when the third highest July and second highest August air temperature occurred (since global records began in 1880). Furthermore, the immigration into Novaya Zemlya coincides with a population explosion and massive expansion of N. xanthomelas in Siberia in 2019–2020. Our air current reconstructions indicate that this species most likely immigrated into Novaya Zemlya from mainland regions situated south-southeast (Polar Urals, Yugorsky Peninsula, and western Yamal) and east (Taymyr) of the archipelago. Overall, our findings reveal that long-distance dispersal events of butterflies to the Arctic islands are always linked to massive expansions of the corresponding species in mainland areas.

Characterizing plume-plate interactions at ocean hotspots from the vertical motion history of volcanic ocean islands

<p>Geologic evidence of island uplift and subsidence can provide important observational constraints on the rheology, thermal evolution, and dynamics of the lithosphere and mantle – all of which have implications for understanding Earth’s heat budget, the styles of deformation that develop at plate boundaries, and the surface expression of mantle convection. Hotspot ocean islands, like the Hawaiian Islands, result from mantle plumes, which may originate as deep as the core-mantle boundary. They often host paleoshorelines, which preserve a geologic record of surface deformation, and they can also be situated far from complex plate boundaries that obscure evidence of dynamic topography – long wavelength, low amplitude topography resulting from mantle flow. Ocean islands therefore provide a unique window to deep earth processes operating today and in the geologic past.<br><br>We examine the relative contribution of lithosphere and mantle processes to surface deflection at ocean hotspots. The seafloor surrounding ocean hotspots is typically 0.5 - 2 km shallower than expected for its age over areas hundreds to >1000 km wide, but the processes generating these bathymetric swells are uncertain. Swells may result from reheating and thinning of the lithosphere and the isostatic effect of replacing colder, denser lithosphere with hotter, less dense upper mantle. Alternately, they may be supported by upward flow of ascending mantle plumes and/or hot, buoyant plume material ponded beneath the lithosphere. Because these two end-member models predict different patterns of seafloor and island subsidence, swell morphology and the geologic record of island drowning may reveal which of these mechanisms dominates the process of swell uplift. We examine swell bathymetry and island drowning at 14 hotspots and find a correspondence between island lifespan and residence time atop swell bathymetry, implying that islands drown as tectonic plate motion transports them past mantle sources of uplift. This correspondence argues strongly for dynamic uplift of the lithosphere at ocean hotspots. Our results also explain global variations in island lifespan on fast- and slow-moving tectonic plates (e.g. drowned islands in the Galápagos <4 Myr old versus islands >20 Myr old above sea level in the Canary Islands), which strongly influence island topography, biodiversity, and climate.<br><br>Over shorter timescales, paleoshorelines on hotspot ocean islands may constrain transient changes in local swell morphology. Accounting for flexural isostatic adjustment of the lithosphere to volcanic loading, we also examine patterns in the residual deflection of paleoshorelines across the Hawaiian Islands that might correspond to non-steady state behavior of the Hawaiian plume. Together, these analyses highlight the unique constraints that island paleoshorelines and topo-bathymetry can place on plume-plate interactions at ocean hotspots.</p>