Processes behind the shift from hunting-gathering to food production lifestyle are multifaceted and not yet completely understood. The Mediterranean coast of NW Africa provides an eclectic ...transitional pattern, namely, a very hesitant transition to food production. The distribution and abundance of early Neolithic domesticated species is disparate and region specific. Climate and environmental change have been often considered as an important influencing factor for this transition. This hypothesis was tested using archeological shells of the rocky intertidal gastropod Phorcus turbinatus recovered from the Ifri Oudadane site in NE Morocco. The oxygen isotope composition (δ18O) of the shell was used to examine whether the hesitant transition to food production was linked to a local climate shift in the Mediterranean Maghreb. Intrashell δ18O values suggest a marked temperature increase from >7.6 to ~7.0 cal. ka BP, the time when Neolithic innovations first appear on site. An additional increase in temperature from ~7.0 to <6.8 cal. ka BP matches with the beginning of the main occupation phase and the doubtless breakthrough of cultivation at Ifri Oudadane. This apparent warming trend, although considered preliminary, seems to match well with warming tendency observed in several published regional climate proxies. Therefore, a temperature shift may have played a role in the timing and implementation of food production in the area. Last growth episode δ18O values suggest that shellfish were harvested throughout most of the year, with noticeable intensification during the cooler half of the year. This preliminary pattern was fairly consistent throughout the Epipaleolithic and early Neolithic phases, pointing to a probable near year-round site occupation rather than a single season settlement. Future research on Ifri Oudadane and other NW African archeological records are much needed to assess whether these patterns persist in Morocco and other Epipaleolithic and early Neolithic settlements in the western Mediterranean Maghreb.
We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary ...research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Human-mediated biological exchange has had global social and ecological impacts. In sub-Saharan Africa, several domestic and commensal animals were introduced from Asia in the pre-modern period; ...however, the timing and nature of these introductions remain contentious. One model supports introduction to the eastern African coast after the mid-first millennium CE, while another posits introduction dating back to 3000 BCE. These distinct scenarios have implications for understanding the emergence of long-distance maritime connectivity, and the ecological and economic impacts of introduced species. Resolution of this longstanding debate requires new efforts, given the lack of well-dated fauna from high-precision excavations, and ambiguous osteomorphological identifications. We analysed faunal remains from 22 eastern African sites spanning a wide geographic and chronological range, and applied biomolecular techniques to confirm identifications of two Asian taxa: domestic chicken (Gallus gallus) and black rat (Rattus rattus). Our approach included ancient DNA (aDNA) analysis aided by BLAST-based bioinformatics, Zooarchaeology by Mass Spectrometry (ZooMS) collagen fingerprinting, and direct AMS (accelerator mass spectrometry) radiocarbon dating. Our results support a late, mid-first millennium CE introduction of these species. We discuss the implications of our findings for models of biological exchange, and emphasize the applicability of our approach to tropical areas with poor bone preservation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Aim
This study aims to reconstruct the evolutionary history of the
Crocidura poensis
species complex and to identify factors driving diversification within it. We tested whether: (a) there ...is a pattern of allopatric differentiation coincident with the location of hypothesized Pleistocene forest refugia, (b) sister taxa are separated by broad rivers, (c) sister taxa occupy adjacent but distinct habitat.
Location
Sub‐Saharan African forests and adjacent savanna.
Taxon
Shrews.
Methods
Analyses were based on 247 specimens collected from across the distribution of the species complex. We reconstructed the phylogeny (Bayesian and maximum likelihood methods) and assessed historical biogeography of this taxonomic group using a combination of mitochondrial and nuclear markers. We mapped the genetic diversity and estimated the divergence times by a relaxed clock model. Informed by multilocus species delimitation methods, we discussed possible taxonomic implications.
Results
This complex is composed of nine major genetic lineages (proposed species). The earliest split within this complex occurred after 2.0–2.4 Ma, which corresponds to a period of increased aridity and/or extreme environmental variability. Most other divergence events occurred after the Early‐Middle Pleistocene Transition (1.2–0.8 Ma). Divergent selection across ecological gradients could explain diversification within the West African lineage. In Central Africa, the observed phylogeographic pattern fits the Pleistocene refuge hypothesis and supports the existence of multiple small rather than a few large forest refugia during glacial maxima. Large rivers, like the Congo and Sanaga Rivers, are important barriers to gene flow for several lineages but probably were not the primary cause of differentiation.
Main conclusions
Both geographic isolation in distinct forest refugia and divergent selection along ecological gradients could explain Pleistocene diversification within this complex.
One of the largest members of Sigmodontinae, the extinct Megaoryzomys curioi from Santa Cruz Island in the Galápagos Archipelago (Ecuador), is traditionally treated as a representative of ...Thomasomyini. We contrasted this hypothesis based on a direct study of craniodental material of M. curioi, including a well-preserved skull assessed through CT-scan examination, within a broader sampling of brachydonts sigmodontines. M. curioi lacks or presents a poorly expressed suspensory process of the squamosal bone, while in Thomasomyini this structure is well developed. In the same way, M. curioi does not exhibit the condition in the dorsal aperture of the ectotympanic displayed by the Thomasomyini, and the morphology of the mandible also contrasts with the widespread condition shown by Thomasomyini. Besides, the procingulum of the first lower molar in M. curioi lacks the typical pattern of Thomasomyini composed of two defined conulids. Overall craniodental morphology in M. curioi favours its allocation to the Oryzomyini. This alternative hypothesis resolves two biogeographical issues connected with the target genus: (1) Galápagos Islands were colonised by members of a single sigmodontine tribe (i.e., Oryzomyini) and (2) within the sigmodontine radiation; members of the Oryzomyini were uniquely capable of reaching oceanic islands.
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Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A 2007 survey of small mammals on Mt. Mantalingahan (2,086 m elevation), southern Palawan Island, Philippines, obtained specimens of a distinctive, previously unknown shrew (Soricidae). We describe ...these specimens as representing a new, monotypic genus and species, Palawanosorex muscorum. The new species was common on Mt. Mantalingahan from 1,550 to 1,950 m (near the peak) but was not detected from 700 to 1,300 m elevation. The previously known native, syntopic shrew, Crocidura palawanensis, has a slender body, slender fore and hind feet, and a long, thin tail with a few long bristles. In contrast, the new species has a stout body, broad fore feet, long claws, and a short tail covered by short, dense fur but no bristles. The dental formula traditionally used would result in assignment of the new species to Suncus, but several distinctive external and cranial features are present, and phylogenetic analyses of thousands of ultraconserved elements suggest P. muscorum is sister to most other Crocidurinae, a clade represented throughout Southeast Asia but numerically dominated by African species. The new species is a distant relative of Suncus murinus (the type species of Suncus) and all other known Southeast Asian species, including the only other shrew known to occur on Palawan (Crocidura batakorum). A time-calibrated phylogenetic analysis estimates divergence between Palawanosorex and its closest known relatives at approximately 10 Ma.
This study presents new insights in the anatomy of genital organs of some large helicid gastropods from northern Africa. The genetic analysis with the markers COI, 16S, H3, and 5.8 S rRNA+ITS2 ...reveales a high support for
and
as separate evolutionary lineages within the Otalini. The position of
as another separate lineage within the Otalini is discussed. "
" clusters within the
clade and confirms that the genus
can be synonymised with
. The genus
differs from all other known genera by possession of a penial appendix. This character state is also found in topotypic
. Examination of the twin penial papilla system in
recovers a reduction of the proximal penial papilla in
. The position of
as a separate subspecies of
is not supported, and it is here considered to be a synonym of the latter species.
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► Recognition of 18 genetically distinct clades including at least three new species. ► Initial radiation on the Canary Islands during the Late Oligocene/Early Miocene. ► ...Re-colonization of NW Africa with continental radiation during the Middle Miocene. ► Main mode of diversification: intra-archipelago and intra-continental speciation.
Among oceanic islands, the Canary Islands offer exceptional opportunities for studying speciation processes due to their habitat diversity and well documented geological history. Based on a combined COI+ITS1 data set for more than 140 specimens, we studied the diversification of the land snail genus Theba on the Canary Islands and adjacent African and European continental areas. Phylogenetic analyses resulted in the recognition of 18 genetically distinct clades including at least three new species. Divergence time estimates suggested an evolution of Theba in the Canarian archipelago and an initial radiation on the three eastern-most islands during the Late Oligocene/Early Miocene. Despite the close proximity of NW Africa to the Canary Islands, the main mode of diversification was intra-archipelago speciation rather than independent colonization of the islands from the mainland. Notably, species from Morocco are nested among species from the Canary Islands, indicating re-colonization of the continent from the islands. The re-colonization of NW Africa occurred during the Middle Miocene and led to a remarkable continental radiation.
Archaeological or paleontological remains are often broken and consequently cannot be used as complete specimens, especially for species identification. Consequently, they are poorly studied, even if ...they could possess species–specific information. Here, we use mandibles of white-toothed shrews and a taphonomic pattern of fragmentation composed of seven pieces to test their validity in species assignment. Using an extant non-ambiguous reference sample of five species, we explore the specific assignments of fragments obtained by a k-NN method of classification, artificially derived from the complete mandible. To describe the form of each piece we use 2D anatomical landmarks and sliding semilandmarks that allow the quantification of objects with no or few true anatomical landmarks. Results show that small fragments still possess species–specific information that is nearly always enhanced when using sliding-landmarks. Moreover, morpho-functional aspects are detected that can affect the species–specific information contained in the fragments.
•We established a pattern of fragmentation on archaeological fragments of shrew mandibles.•We divided an extant referential of complete shrew mandibles into seven fragments.•We specifically classified each fragment using sliding and anatomical landmarks.•We demonstrated that sliding-landmarks offer the best solution.•We showed that even smallest fragments still possess an important specific information.
Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island ...size emphasizes the importance of geographic isolation (allopatry) in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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