On the cover: Mucuna gigantea (Willd.) DC. In the Malesian archipelago. Photo: T. Utteridge.
On the cover: Mucuna gigantea (Willd.) DC. In the Malesian archipelago. Photo: T. Utteridge.
Whether widespread gene flow among primates is emblematic of their initial radiation or resulted from secondary contactremains a long-standing question. We address this question on ‘sinica’ group macaques, highlighting the origin of the white-cheeked macaque (Macaca leucogenys).
Eastern Himalayan highlands of Arunachal Pradesh, India.
Macaca leucogenys Li, Zhao, Fan, 2015b (Cercopithecidae).
Mitochondrial genomes and Y-chromosomal TSPY gene sequences of WCM were obtained from two distant populations through low-depth genome sequencing. Phylogenetic analyses were conducted along with sequences of other available species within the genus Macaca.
We observed the presence of a single maternal lineage but two parental lineages. Interestingly, one paternal lineage of the white-cheeked macaque clustered with a common lineage of M. assamensis and M. munzala. The other paternal lineage clustered with the sequences of the white-cheeked macaque from the type locality in Southeastern Tibet.
The result indicates a possible historic male-mediated introgression in the white-cheeked macaque, which is also present in the two other species belonging to the ‘sinica’ group. Therefore, extensive gene flow in ‘sinica’ group macaques possibly came from one or more introgression events in the past that also played a role in the origin and evolution of these macaque species.
Understanding the worldwide distribution of species has fascinated scientists at least since Alfred Russel Wallace. Global patterns of belowground biodiversity may fundamentally differ from those of aboveground organisms. Here, we examine the global pattern and potential mechanisms driving the endemism and overlap of a soil microarthropod taxon.
Global.
Oribatida, Acari.
We investigated the global distribution of oribatid mites in five biogeographic regions including North America, South America, Eurasia, Africa and Oceania using a world list on the distribution of ~11,400 described species (including subspecies) at species, genera and family levels.
We found that most “endemic” (i.e., only occurring in one of the regions) species (4297) and also genera (143) occurred in Eurasia indicating that this region was the centre of radiation of oribatid mites. Within Eurasia, oribatid mite diversity was highest in Southeast Asia (1975 species) likely reflecting the long tropical history of this region (at least 200 million years), and also high fluctuations in water levels and island formation on the Sunda Shield. On a family level, oribatid mite diversity did not differ between biogeographic regions indicating that oribatid mites are much older than the tropics and older than the existence of Pangaea supporting the view of their origin in the early Palaeozoic. Finally, among the 55 species that occurred in all biogeographic regions nearly 50% reproduce by thelytoky and colonize high latitude ecosystems, indicating that compared to sexual species a disproportionally high number of parthenogenetic species is distributed worldwide suggesting that they possess a general-purpose genotype. The other ~50% sexuals predominantly occur in tropical/subtropical regions across biogeographic regions supporting the view that resource shortage in tropical regions favours sex. Our findings highlight the importance of biogeographical studies of soil animals to better understand their diversity, distribution and life history strategies.
Dispersal and connectivity play important roles in shaping the population structure of giant kelp, Macrocystis pyrifera, across the western coast of South America. Its high potential dispersal capacity suggests the existence of metapopulations, where discrete habitat patches or groups of patches form subpopulations that interact at some level. However, the dispersal patterns of giant kelp in this region have not been quantified. This study assesses the dispersal and settlement of Macrocystis pyrifera in the southeast Pacific, specifically focusing on the impact of environmental variables and ocean currents within the Humboldt Current System.
Southeast Pacific (coast of Chile and Peru).
1997–2008.
Macrocystis pyrifera (giant kelp).
Using a combination of hydrodynamic and individual-based models, we analysed kelp fragment movements over 12 years, with a particular emphasis on the effects of the El Niño-Southern Oscillation (ENSO) and seasonal changes.
Our results highlight a key settlement area in the southern Chilean region. We found that shorter travel distances of kelp fragments increased the likelihood of reaching a suitable habitat, underscoring the importance of local environmental conditions. We delineated intricate northward dispersal paths for kelp fragments, which appear to be governed by the interplay of wind and ocean current dynamics. Seasonal variations, notably in autumn and winter, favour the likelihood of reaching a settlement area due to favourable winds. Furthermore, ENSO events appear to influence dispersal distances, with fragments travelling the longest distances during El Niño phases.
These findings are essential for informing kelp conservation strategies in the context of climate change, emphasizing the necessity of considering local and seasonal environmental factors alongside ENSO impacts.
On the cover: A poison-dart (Ameerega munduruku) frog sitting on the rocky bank of a rivulet in south Amazon. Photo: André Teles.
Endemicity is one of the main indicators to describe and compare regional biotas. Endemic species can originate from inter- or intra-regional speciation, but few studies have measured the relative contribution of these two mechanisms in the assembly of regional biotas. We investigated the relative contributions of inter- and intra-regional speciation in assembling the endemic avifauna of the Cerrado, the largest South American savanna region. We also tested hypotheses about the relationships between habitat preferences with range size and evolutionary age, as well as whether the biogeographical relationships between the Cerrado and neighbouring regions are randomly distributed around the region.
Cerrado, central South America.
Birds.
We used distributional and phylogenetic data of Cerrado endemic birds.
The proportion of endemic species in the Cerrado region is relatively low, when compared to other organisms living in the same region. Furthermore, we found that inter-regional speciation is the primary factor promoting bird endemism in the Cerrado and that sister species of Cerrado endemics are concentrated in northwestern (forest species) and southwestern (nonforest species) South America. We also found that nonforest endemic bird species do not necessarily have larger geographical ranges than forest endemic species; however, nonforest endemic species are evolutionarily older than forest species.
The assembly of the Cerrado endemic avifauna is complex and idiosyncratic. The intricate history of the Cerrado endemic avifauna suggests that it is constantly exchanging species with its neighbouring regions. Due to its high ecological heterogeneity, the Cerrado ecosystems are capable of harbouring populations of both endemic and non-endemic species acquired during periods of significant biotic exchange.
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