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"Pygmies."
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Insights into the Demographic History of African Pygmies from Complete Mitochondrial Genomes
Pygmy populations are among the few hunter-gatherers currently living in sub-Saharan Africa and are mainly represented by two groups, Eastern and Western, according to their current geographical distribution. They are scattered across the Central African belt and surrounded by Bantu-speaking farmers, with whom they have complex social and economic interactions. To investigate the demographic history of Pygmy groups, a population approach was applied to the analysis of 205 complete mitochondrial DNA (mtDNA) sequences from ten central African populations. No sharing of maternal lineages was observed between the two Pygmy groups, with haplogroup L1c being characteristic of the Western group but most of Eastern Pygmy lineages falling into subclades of L0a, L2a, and L5. Demographic inferences based on Bayesian coalescent simulations point to an early split among the maternal ancestors of Pygmies and those of Bantu-speaking farmers (∼70,000 years ago [ya]). Evidence for population growth in the ancestors of Bantu-speaking farmers has been observed, starting ∼65,000 ya, well before the diffusion of Bantu languages. Subsequently, the effective population size of the ancestors of Pygmies remained constant over time and ∼27,000 ya, coincident with the Last Glacial Maximum, Eastern and Western Pygmies diverged, with evidence of subsequent migration only among the Western group and the Bantu-speaking farmers. Western Pygmies show signs of a recent bottleneck 4,000–650 ya, coincident with the diffusion of Bantu languages, whereas Eastern Pygmies seem to have experienced a more ancient decrease in population size (20,000–4,000 ya). In conclusion, the results of this first attempt at analyzing complete mtDNA sequences at the population level in sub-Saharan Africa not only support previous findings but also offer new insights into the demographic history of Pygmy populations, shedding new light on the ancient peopling of the African continent.
Journal Article
Lophotettix verhaaghi (Orthoptera, Tetrigidae), a new species of pygmy grasshoppers from Peru with a 3D scan of the holotype
The genus Lophotettix Hancock, 1909 belongs to a small subfamily of Tetrigidae, Lophotettiginae Hancock, 1909. To date, it included six species that are rarely observed and lack reliable distribution data. In this paper, we describe a new species, L. verhaaghi sp. nov., from Peru and provide a digital 3D model of its holotype. The new species resembles L. alticristatus but has rounded lateral lobes and fewer projections on the anterior margin of the pronotal crest. The distribution patterns of Lophotettiginae across multiple zones of endemism in the Amazonian region are discussed.
Journal Article
Two new pygmy squids, Idiosepius kijimuna n. sp. and Kodama jujutsu n. gen., n. sp. (Cephalopoda: Idiosepiidae) from the Ryukyu Islands, Japan
Two new pygmy squid from the Ryukyu archipelago, Japan, are described: Kodama jujutsu, n. gen., n. sp. and Idiosepius kijimuna, n. sp. They differ from all other nominal species in a combination of traits, including the number of tentacular club suckers, shape of the funnel-mantle locking-cartilage, modification of the male hectocotylus and the structure of the gladius and nuchal-locking cartilage, in addition to mitochondrial DNA markers (12S, 16S and COI). They are both known from Okinawa Island and there is some overlap in their distributions. In a molecular phylogeny that includes all nominal Idiosepiidae, Kodama jujutsu, n. gen., n. sp. is sister taxon to a clade containing Xipholeptos Reid & Strugnell, 2018 and Idiosepius Steenstrup, 1881. Xipholeptos and Idiosepius are sister taxa. Idiosepius spp. now includes seven nominal species. In addition, aspects of the behaviour of the new species are described.
Journal Article
Xylem form and function under extreme nutrient limitation
• Xylem anatomy and function have large implications for plant growth as well as survival during drought, but the impact of nutrient limitation on xylem is not fully understood. This study examines the pygmy forest in California, a plant community that experiences negligible water stress but is severely stunted by low-nutrient and acidic soil, to investigate how nutrient limitation affects xylem function.
• Thirteen key anatomical and hydraulic traits of stems of four species were compared between pygmy forest plants and nearby conspecifics growing on richer soil.
• Resistance to cavitation (P50), a critical trait for predicting survival during drought, had highly species-specific responses: in one species, pygmy plants had a 26% decrease in cavitation resistance compared to higher-nutrient conspecifics, while in another species, pygmy plants had a 56% increase in cavitation resistance. Other traits responded to nutrient limitation more consistently: pygmy plants had smaller xylem conduits and higher leaf-specific conductivity (K
L) than conspecific controls.
• Edaphic stress, even in the absence of water stress, altered xylem structure and thus had substantial impacts on water transport. Importantly, nutrient limitation shifted cavitation resistance in a species-specific and unpredictable manner; this finding has implications for the assessment of cavitation resistance in other natural systems.
Journal Article
New genera and species of Ripipterygidae (Orthoptera, Tridactyloidea) from mid-Cretaceous Kachin amber
Two new genera and species of Ripipterygidae Ander, 1939 are described from mid-Cretaceous Kachin amber of Northern Myanmar. Ozymandipteryx campana gen. et sp. nov. is remarkable for its absent or very reduced metatarsus. In modern species of Tridactyloidea, a reduced metatarsus can only be found in the Tridactylidae Brullé, 1835 genera Ellipes Scudder, 1902 and Xya Latreille, 1809, but not in Ripipterygidae. Magnidactylus robustus Xu et al., 2020, type species of the genus, is found to share the character of a fully reduced metatarsus (apical spurs were previously misinterpreted as metatarsus), but M. robustus differs from O. campana in several important characters and hence remains a separate genus. However, a new genus Yakkhapipteryx is erected to include the other two former Magnidactylus species M. mirus Gu et al., 2022 ( Yakkhapipteryx mirus comb. nov. ) and M. gracilis Gu et al., 2022 ( Yakkhapipteryx gracilis comb. nov. ), which both have a metatarsus in normal condition. Another newly described taxon is Ciconipteryx bidactylus gen. et sp. nov. This species is the first fossil Ripipterygidae with only two dactyls on its protibia, a feature it shares with the modern species Mirhipipteryx pulicaria (Saussure, 1896). Ciconipteryx bidactylus stands out due to its long mid- and hindlegs in relation to its body size. This character may have enabled it to perform very efficient jumps. The new species add to the diversity of Ripipterygidae from Kachin amber, expanding our knowledge of this little studied family and raising new possibilities for interpreting their evolutionary history.
Journal Article
The Future Is in the Younger Generations: Baka Children in Southeast Cameroon Have Extensive Knowledge on Medicinal Plants
In the context of global change, understanding the knowledge and values given to plants is crucial for choosing relevant approaches towards a more sustainable future. Children are central holders of ethnobotanical knowledge, yet they are still under-considered in ethnobotany. Our study explored the medicinal knowledge of children of the Baka, forager-horticulturalists from Cameroon. We assessed the diversity of medicinal plants they know, the different ailments treated, and whether they could name complete herbal recipes. Using a mixed-methods approach, we combined ex situ interviews (freelisting and knowledge surveys) with in situ methods (walk-in-the-woods trips with voucher collection) with 106 children from 5 to 16 years old. They listed 128 local names of medicinal plants, which we linked to 126 different plant species. While the ex situ and in situ methods had some overlap in the diversity of medicinal plants reported, they also revealed substantial knowledge unique to each method. Our insights provide further evidence of children’s considerable ethnobotanical knowledge and the extent to which different field methods can retrieve such knowledge. We discuss the methodological tools to be developed with and for children to put childhood at the center stage of ethnobotanical approaches for the future.
Journal Article
The evolution of body size and shape in the human career
Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the ‘best’ for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus. The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans.
This article is part of the themed issue ‘Major transitions in human evolution’.
Journal Article
Differences between Pygmy and Non-Pygmy Hunting in Congo Basin Forests
We use data on game harvest from 60 Pygmy and non-Pygmy settlements in the Congo Basin forests to examine whether hunting patterns and prey profiles differ between the two hunter groups. For each group, we calculate hunted animal numbers and biomass available per inhabitant, P, per year (harvest rates) and killed per hunter, H, per year (extraction rates). We assess the impact of hunting of both hunter groups from estimates of numbers and biomass of prey species killed per square kilometre, and by examining the proportion of hunted taxa of low, medium and high population growth rates as a measure of their vulnerability to overhunting. We then map harvested biomass (kg -1 P -1 Yr -1 ) of bushmeat by Pygmies and non-Pygmies throughout the Congo Basin. Hunting patterns differ between Pygmies and non-Pygmies; Pygmies take larger and different prey and non-Pygmies sell more for profit. We show that non-Pygmies have a potentially more severe impact on prey populations than Pygmies. This is because non-Pygmies hunt a wider range of species, and twice as many animals are taken per square kilometre. Moreover, in non-Pygmy settlements there was a larger proportion of game taken of low population growth rate. Our harvest map shows that the non-Pygmy population may be responsible for 27 times more animals harvested than the Pygmy population. Such differences indicate that the intense competition that may arise from the more widespread commercial hunting by non-Pygmies is a far more important constraint and source of conflict than are protected areas.
Journal Article