Complete Chloroplast Genome Variants Reveal Discrete Long-Distance Dispersal Routes of Rhizophora in the Western Indian Ocean

Historical processes of long-distance migration and ocean-wide expansion feature the global biogeographic pattern of Rhizophora species. Throughout the Indian Ocean, Rhizophora stylosa and Rhizophora mucronata seem to be a young phylogenetic group with an expansion of R. mucronata toward the Western Indian Ocean (WIO) driven by the South Equatorial Current (SEC). Nuclear microsatellites revealed genetic patterns and breaks; however, the estimation of propagule dispersal routes requires maternally inherited cytoplasmic markers. Here, we examine the phylogeography of 21 R. mucronata provenances across a >4,200 km coastal stretch in the WIO using R. stylosa as an outgroup. Full-length chloroplast genome (164,474 bp) and nuclear ribosomal RNA cistron (8,033 bp) sequences were assembled. The boundaries, junction point, sequence orientation, and stretch between LSC/IRb/SSC/IRa/LSC showed no differences with R. stylosa chloroplast genome. A total of 58 mutations in R. mucronata encompassing transitions/transversions, insertions-deletions, and mononucleotide repeats revealed three major haplogroups. Haplonetwork, Bayesian maximum likelihood (ML), and approximate Bayesian computation (ABC) analyses supported discrete historical migration events. An ancient haplogroup A in the Seychelles and eastern Madagascar was as different from other haplogroups as from R. stylosa. A star-like haplonetwork referred as the recent range expansion of haplogroup B from northern Madagascar toward the African mainland coastline, including a single variant spanning >1,800 km across the Mozambique Channel area (MCA). Populations in the south of Delagoa Bight contained haplogroup C and was originated from a unique bottleneck dispersal event. Divergence estimates of pre- and post-Last Glacial Maximum (LGM) illustrated the recent emergence of Rhizophora mangroves in the WIO compared to other oceans. Connectivity patterns could be aligned with the directionality of major ocean currents. Madagascar and the Seychelles each harbored haplogroups A and B, albeit among spatially separated populations, explained from a different migration era. Likewise, the Aldabra Atoll harbored spatially distinct haplotypes. Nuclear ribosomal cistron (8,033 bp) variants corresponded to haplogroups and confirmed admixtures in the Seychelles and Aldabra. These findings shed new light on the origins and dispersal routes of R. mucronata lineages that have shaped their contemporary populations in large regions of the WIO, which may be the important information for defining marine conservation units both at ocean scale and at the level of small islands.

Dispersal of earthworms from the Rudny Altai (Kazakhstan) into Western Siberia

The aim of our study was to determine the current distribution, habitats, ecology, and possible dispersal routes of three species of the Rudny Altai (East Kazakhstan): Eisenia tracta, E. nana, and E. ventripapillata. We found that these species dispersed far beyond their original distribution into the flatland part of western Siberia (Russia) up to the central forest steppe of the Omsk oblast. E. tracta, E. nana, and E. ventripapillata were found in both floodplains and interfluvials. Hydrochory was the most plausible way of northward dispersal, while on interfluvials, they were probably introduced by humans. The studied species showed no preference for a particular habitat or river bank. The habitats were diverse and significantly different from the original ones in Rudny Altai. The factors that allowed E. tracta, E. nana, and E. ventripapillata to colonize western Siberia were probably their wide tolerance range to soil pH, temperature, density, and humidity, along with the decrease of winter soil freezing in recent decades. This is the first information about the occurrence of these species of earthworms in Siberia.

Giants Among Dwarfs: The Arrival Of A New Clade Of Southern Dinosaurs In The Latest Cretaceous Of Europe

The origin of the last sauropod dinosaur communities in Europe and their evolution in the last 15 million years of the Cretaceous has become a complex phylogenetic and paleobiogeographic puzzle portrayed by the controversy on the alleged coexistence of immigrant Gondwana-related taxa alongside relictual and insular clades. In this context, here we describe a new titanosaurian sauropod dinosaur, Abditosaurus kuhnei gen. et sp. nov., from the Upper Cretaceous (Maastrichtian) Tremp Group of Catalonia (Spain). Phylogenetic analyses recover Abditosaurus separately from the rest of European titanosaurs, within a clade of South American and African saltasaurines. The affinity of the new taxon with southern landmasses is reinforced by the spatiotemporal co-occurrence with Gondwanan titanosaur oospecies in southern Europe. The large size and the lack of osteohistological features related to insular dwarfism support the idea that Abditosaurus belongs to an immigrant lineage, unequivocally distinct from the island dwarfs of the European archipelago. The arrival of Abditosaurus lineage to the Ibero-Armorican island is hypothesized to have occurred at the earliest Maastrichtian (72 Ma), probably as a result of a global and regional sea-level drop that reactivated the ancient dispersal routes between NW Africa and SW Europe. The arrival of large-bodied titanosaurs to the European archipelago produced dramatic changes in the insular ecosystems and important evolutionary changes in the dinosaur faunas, especially with respect to the ‘island rule’ effect.

Primates from the Baynunah Formation

Fossil primates of the Baynunah Formation are represented by only two cercopithecoid specimens: AUH 35, a male lower canine of an indeterminate cercopithecid from site JDH-3, and AUH 1321, a lower molar of a guenon from site SHU 2-2. Although rare, these cercopithecoid primates are significant in terms of their age and biogeographic implications. AUH 1321 is the earliest known guenon in the fossil record, and at ~8 – 6.5 Ma, it is also one of the earliest cercopithecines known. The age and geographic position of both specimens in the Arabian Peninsula supports late Miocene Eurasian dispersal scenarios for cercopithecoid primates out of Africa and through Arabia before the Messinian Crisis. Whether or not this dispersal included both cercopithecines (macaques) and colobines is unclear, and it re- mains possible that both groups also dispersed across the Mediterranean Basin or Straits of Gibraltar during the Messinian as well. Among the potential Arabian dispersal routes, there is perhaps some support for the southern path over the Straits of Bab el Mandeb based on the presence of ~8 – 5.5 Ma cercopithecine and colobine fossils in the East African fossil record, geographically close to the Horn of Africa.

What's in a mass?

This short essay pretends to make the reader reflect on the concept of biological mass and on the added value that the determination of this molecular property of a protein brings to the interpretation of evolutionary and translational snake venomics research. Starting from the premise that the amino acid sequence is the most distinctive primary molecular characteristics of any protein, the thesis underlying the first part of this essay is that the isotopic distribution of a protein's molecular mass serves to unambiguously differentiate it from any other of an organism's proteome. In the second part of the essay, we discuss examples of collaborative projects among our laboratories, where mass profiling of snake venom PLA2 across conspecific populations played a key role revealing dispersal routes that determined the current phylogeographic pattern of the species.

Modeling Potential Dispersal Routes for Giant Pandas in Their Key Distribution Area of the Qinling Mountains, China

The national surveys on giant panda (Ailuropoda melanoleuca) population and habitat quality have shown a high-density population of this species in the Qinling Mountains, China. We investigated five adjacent nature reserves (NR), i.e., the key distribution area of giant pandas in the Qinling Mountains, to model and identify the potential dispersal routes for giant pandas. We hypothesized that giant pandas will spread to neighboring areas when the population of the species keeps increasing. Habitat suitability was firstly evaluated based on environmental and disturbance factors. We then identified source and sink patches for giant pandas’ dispersal. Further, Minimum Cumulative Resistance (MCR) model was applied to calculate cost of movement. Finally, the Current Theory was adopted to model linkages between source and sink patches to explore potential dispersal routes of giant pandas. Our results showed that (1) the three large source patches and eight potential sink patches were identified; (2) the 14 potential corridors were predicted for giant pandas dispersing from source patches to the neighboring areas; (3) through the predicted corridors, the giant pandas in the source patches could disperse to the west, the south and the east sink patches. Our research revealed possible directional patterns for giant pandas’ dispersal in their key distribution area of the Qinling Mountains, and can provide the strong recommendations in policy and conservation strategies for improving giant panda habitat management in those identified sink patches and also potential dispersal corridors.

Potential mammalian species for investigating the past connections between Amazonia and the Atlantic Forest

Much evidence suggests that Amazonia and the Atlantic Forest were connected through at least three dispersion routes in the past: the Eastern route, the central route, and the Western route. However, few studies have assessed the use of these routes based on multiple species. Here we present a compilation of mammal species that potentially have dispersed between the two forest regions and which may serve to investigate these connections. We evaluate the present-day geographic distributions of mammals occurring in both Amazonia and the Atlantic Forest and the likely connective routes between these forests. We classified the species per habitat occupancy (strict forest specialists, species that prefer forest habitat, or generalists) and compiled the genetic data available for each species. We found 127 mammalian species presently occurring in both Amazonia and the Atlantic Forest for which, substantial genetic data was available. Hence, highlighting their potential for phylogeographic studies investigating the past connections between the two forests. Differently from what was previously proposed, the present-day geographic distribution of mammal species found in both Amazonia and the Atlantic Forest points to more species in the eastern portion of the dry diagonal (and adjoining forested habitats). The Central route was associated with the second most species. Although it remains to be seen how this present-day geography reflects the paleo dispersal routes, our results show the potential of using mammal species to investigate and bring new insights about the past connections between Amazonia and the Atlantic Forest.

Reconnaissance of Paleolithic sites in Faid area, region of Ha’il in northern Saudi Arabia, A project progress report. Ahmed Nassr, Ahmed Elhassan, Mohammed al-Hajj, Ali Tueaiman

The ongoing archaeological survey and excavations in Faid area north of Saudi Arabia uncovered remains of a large early Islamic settlement. During excavation of season 2019 Paleolithic artefacts discovered in the building foundations indicated of Paleolithic site buried partially by the settlement ruins. An archaeological exploration carried out in the area around the site during March 2020, where are three Paleolithic sites documented Faid 1 – Faid 3). In February 2021 archaeological survey extended to the east and west, where are new four Paleolithic sites have been discovered (Faid 4 – Faid 7). The archaeological sites represented two main Paleolithic traditions, Acheulean identified from the bifaces and Middle Paleolithic horizon represented by prepared core production and bifacial point referable to Levallois meth. Faid 2 is a unique Acheulean site, where a systematic survey shows agglomeration of LCTs covered an area of 15 hectares. Bifaces (handaxes and cleavers) are the most conspicuous artefacts characteristics. Thus the archaeological sites localities and lithics technocomplex has direct relevance for assessing hominin dispersal routes along Arabia to Eurasia.