scholarly journals Late Miocene lineage divergence and ecological differentiation of rare endemicJuniperus blancoi: clues for the diversification of North American conifers

2014 ◽  
Vol 203 (1) ◽  
pp. 335-347 ◽  
Author(s):  
Alejandra Moreno-Letelier ◽  
Alicia Mastretta-Yanes ◽  
Timothy G. Barraclough
Keyword(s):  
Late Miocene ◽  
North American ◽  
Ecological Differentiation ◽  
Lineage Divergence

Spatiotemporal palaeodiversity patterns of modern crocodiles (Crocodyliformes: Eusuchia)

2019 ◽  
Vol 189 (2) ◽  
pp. 635-656 ◽  
Author(s):  
Ane De Celis ◽  
Iván Narváez ◽  
Francisco Ortega
Keyword(s):  
South America ◽  
Least Squares ◽  
Late Miocene ◽  
North American ◽  
Fossil Record ◽  
Generalized Least Squares ◽  
Global Scale ◽  
Biotic Factors ◽  
Species Dynamics ◽  
Over Time

Abstract Eusuchia is a crocodyliform clade with a rich and diverse fossil record dating back to the Mesozoic. There are several recent studies that analyse crocodyliform palaeodiversity over time, but none of them focuses exclusively on eusuchians. Thus, we estimated subsampled eusuchian palaeodiversity species dynamics over time not only at a global scale, but also by continents and main crocodylian lineages (Alligatoroidea, Crocodyloidea and Gavialoidea). These estimates reveal complex spatiotemporal palaeodiversity patterns, in which two maxima can be detected: the first during the Palaeocene and the second, which is also the biggest, in the middle-late Miocene. The Palaeocene shift is related to a North American alligatoroid diversification, whereas the middle–late Miocene maximum is related to a diversification of the three main Crocodylia lineages in Gondwanan land masses, but especially in South America. Additionally, a model-based study using generalized least squares was carried out to analyse the relationships between different abiotic and sampling proxies and eusuchian palaeodiversity. The results show that palaeotemperature is the most important factor amongst the analysed proxies, in accordance with previous studies. However, the results suggest that, along with palaeotemperature, other abiotic and/or biotic factors might also be driving eusuchian palaeodiversity dynamics.

scholarly journals A time and a place for everything: phylogenetic history and geography as joint predictors of oak plastome phylogeny

Genome ◽  
2017 ◽  
Vol 60 (9) ◽  
pp. 720-732 ◽  
Author(s):  
Kasey K. Pham ◽  
Andrew L. Hipp ◽  
Paul S. Manos ◽  
Richard C. Cronn
Keyword(s):  
Dna Sequences ◽  
North American ◽  
Introgressive Hybridization ◽  
White Oak ◽  
Gene Migration ◽  
The North ◽  
Geographic Structure ◽  
Phylogenetic Studies ◽  
Phylogenetic Informativeness ◽  
Lineage Divergence

Owing to high rates of introgressive hybridization, the plastid genome is poorly suited to fine-scale DNA barcoding and phylogenetic studies of the oak genus (Quercus, Fagaceae). At the tips of the oak plastome phylogeny, recent gene migration and reticulation generally cause topology to reflect geographic structure, while deeper branches reflect lineage divergence. In this study, we quantify the simple and partial effects of geographic proximity and nucleome-inferred phylogenetic history on oak plastome phylogeny at different evolutionary scales. Our study compares pairwise phylogenetic distances based on complete plastome sequences, pairwise phylogenetic distances from nuclear restriction site-associated DNA sequences (RADseq), and pairwise geographic distances for 34 individuals of the white oak clade representing 24 North American and Eurasian species. Within the North American white oak clade alone, phylogenetic history has essentially no effect on plastome variation, while geography explains 11%–21% of plastome phylogenetic variance. However, across multiple continents and clades, phylogeny predicts 30%–41% of plastome variation, geography 3%–41%. Tipwise attenuation of phylogenetic informativeness in the plastome means that in practical terms, plastome data has little use in solving phylogenetic questions, but can still be a useful barcoding or phylogenetic marker for resolving questions among major clades.

scholarly journals Patterns of evolution in North American Neogene mammals

1992 ◽  
Vol 6 ◽  
pp. 146-146
Author(s):  
Louis Jacobs ◽  
Christine Janis
Keyword(s):  
Late Miocene ◽  
North American ◽  
Morphological Changes ◽  
Ground Squirrels ◽  
Deer Mice ◽  
Leg Length ◽  
Vegetational Change ◽  
Late Neogene ◽  
Tree Squirrels

The Neogene of North American represents a time of climatic change from an initially warm, non-arid climate to one with the development of increasing aridity, with warming temperatures through the early part and fluctuating (but basically cooler) temperatures through the later part. This reflects the classic story of a vegetational change from woodland to savanna and eventually to prairie. Note that the transition to true savanna in the Late Miocene was considerably earlier than the first savannas in the Pliocene of the Old World. The evolutionary trends in mammals reflect these climactic and vegetational changes.Some general broad trends are as follows: the replacement of terrestrial and subfossorial moles and geomyid rodents with more specialized fossorial ones; a decrease in the diversity of brachydont rodents and an increase in the diversity of hypsodont ones (including saltatorial forms), and a late Neogene diversification of microtines and deer mice; a decline in the diversity of tree squirrels and terrestrial beavers, and an increase in diversity of ground squirrels and aquatic beavers; the replacement of carnivores belong to more archaic families by more modern types; taxa and an increase in body size, leg length, and hypsodonty in most ungulate taxa, including oreodonts, protoceratids, camelids, antilocaprids, rhinos and equine horses although a couple of taxa show an apparent reversal of these trends: dromomerycids (cervoids) and some anchitherine horses show other morphological changes that suggest progressively more woodland-adapted (rather than savanna-adapted) forms. Tapirs and (to a lesser extent) peccaries seem little affected by the Neogene changes, and persist until the Recent.The Neogene was also punctuated by immigration events (primarily from Asia) and extinctions. The start of the Neogene shows surprisingly little change, with many Paleogene “holdovers”: some new forms appear as either the result of evolution in situ (e.g. equine horses and osteoborine dogs) or as immigrants (e.g. chalicotheres and hemicyonine “dog bears”). The initial major immigrations are during the late Early Miocene, marked by the Asian appearances of true felids (replacing the “false saber-tooths” or nimravids), pecoran ruminants (replacing the hypertragulids), more derived rhinos (replacing the diceratherine rhinos), neomustelids and procyonids. Archaic suoids such as anthracotheres and entelodonts become extinct at this time, and only the more derived ticholeptine oreodonts survive this period. The start of the Middle Miocene is notable for the appearance of proboscideans and deer mice. The Late Miocene sees the decline and eventual disappearance of hedgehogs, archaic carnivores (hemicyonine bears and amphicyonids), most browsing ungulates (oreodonts, protoceratids, many camelids, anchitherine horses, dromomerycids, merycodontine antilocaprids, hornless ruminants, chalicotheres, bunodont gomphotheres), and rhinos. New taxa appearing including ursine bears (immigrants), oversized camels and more derived gomphotheres (in situ evolution). The Pliocene marks a new wave of immigration: microtines, hyenas, true saber-tooths, and cervids come in from Asia; ground sloths (two families appearing in the Late Miocene), glyptodonts, armadillos and capybaras come in from South America. Most mammals that survived the end Miocene extinctions persist, but for many of them (such as horses, camels and antilocaprids) the generic diversity is greatly reduced.

scholarly journals New insights on the Early Pleistocene equids from Roca-Neyra (France, central Europe): implications for the Hipparion LAD and the Equus FAD in Europe

2020 ◽  
pp. 1-20
Author(s):  
Omar Cirilli ◽  
Raymond L. Bernor ◽  
Lorenzo Rook
Keyword(s):  
Central Europe ◽  
Late Miocene ◽  
North American ◽  
Statistical Analyses ◽  
Early Pleistocene ◽  
Morphological Description ◽  
The North ◽  
Azov Sea

Abstract We undertake a redescription of the equid sample from the Early Pleistocene of Roca-Neyra, France. This locality has been recently calibrated at the Pliocene/Pleistocene boundary (2.6 ± 0.2 Ma) and therefore it is of interest for the first appearance of the genus Equus and last appearance of hipparionine horses. The Roca-Neyra equid sample, re-analyzed herein using morphological, morphometrical, and statistical analyses, has revealed the co-occurrence of Plesiohipparion cf. ?P. rocinantis and Equus cf. E. livenzovensis. The analysis undertaken on several European, African, and Asian “Hipparion” sensu lato species from late Miocene to Early Pleistocene has revealed different remnant Hipparion lineages in the Plio-Pleistocene of Europe: Plesiohipparion, Proboscidippaion, and likely Cremohipparion. The discovery of the first European monodactyl horse, Equus cf. E. livenzovensis correlates Roca-Neyra with other 2.6 Ma European localities in Italy, Spain, and in the Khapry area (Azov Sea region). The morphological description of the Equus cf. E. livenzovensis lower cheek teeth has highlighted intermediate features between the North American Pliocene species Equus simplicidens and Early Pleistocene European Equus stenonis. Our study supports the hypothesis that E. livenzovensis is a plausible evolutionary predecessor for the Equus stenonis group. These observations underscore the importance of Roca-Neyra as an important locality for the last European hipparions and the first Equus in the Early Pleistocene of Europe.

scholarly journals Mountain uplift and the threshold for sustained Northern Hemisphere Glaciation

2009 ◽  
Vol 5 (6) ◽  
pp. 2439-2464 ◽  
Author(s):  
G. L. Foster ◽  
D. J. Lunt ◽  
R. R. Parrish
Keyword(s):  
Northern Hemisphere ◽  
Late Miocene ◽  
North American ◽  
Isotope Composition ◽  
Ice Sheet ◽  
Threshold Value ◽  
North American Cordillera ◽  
North American Continent ◽  
The North ◽  
Cordilleran Ice Sheet

Abstract. The Miocene (~24 to ~5 million years ago) was a period of relative global warmth (e.g. Zachos et al. 2001) characterised by the glaciation of Antarctica only. Paradoxically, the majority of available proxy data suggest that during the Miocene pCO2 was similar, or even lower, than the pre-industrial levels (280 ppmv; Pagani et al., 1999; Pearson and Palmer, 2000; Kürschner et al., 1996, 2008) and at times probably crossed the modelled threshold value required for sustained glaciation in the Northern Hemisphere (DeConto et al., 2008). Records of ice rafted debris and the oxygen isotope composition of benthic foraminifera suggest that at several times over the last 25 million years substantial amounts of continental ice did build up in the Northern Hemisphere but none of these led to sustained glaciation. In this contribution we review evidence that suggests that in the Miocene the North American Cordillera was, at least in parts, considerably lower than today. We present new GCM simulations that imply that Late Miocene uplift of the North American Cordillera would have resulted in significant cooling of Northern North American Continent. Offline ice sheet modelling, driven by these GCM outputs, suggests that with a reduced topography inception of the Cordilleran ice sheet is prohibited, and there is a small, but potentially significant, reduction in the amount of ice grown on Baffin Island. This suggests uplift of the North American Cordillera in the Late Miocene may have played an important role in priming the climate for the intensification of Northern Hemisphere glaciation in the Late Pliocene.

scholarly journals A polygenic architecture with conditionally neutral effects underlies ecological differentiation in Silene

2021 ◽  
Author(s):  
Susanne Gramlich ◽  
Xiaodong Liu ◽  
Adrien Favre ◽  
C. Alex Buerkle ◽  
Sophie Karrenberg
Keyword(s):  
Native Species ◽  
Genetic Architecture ◽  
Natural Habitat ◽  
Silene Dioica ◽  
Ecological Differentiation ◽  
Reduced Representation ◽  
Negative Effect ◽  
Lineage Divergence ◽  
Hidden Variation ◽  
Positive Effect

Ecological differentiation can drive speciation but it is unclear how the genetic architecture of habitat-dependent fitness contributes to lineage divergence. We investigated the genetic architecture of cumulative flowering, a fitness component, in second-generation hybrids between Silene dioica and S. latifolia transplanted into the natural habitat of each species. We used reduced-representation sequencing and Bayesian Sparse Linear Mixed Models (BSLMMs) to analyze the genetic control of cumulative flowering in each habitat. Our results point to a polygenic architecture of cumulative flowering. Allelic effects were mostly beneficial or deleterious in one habitat and neutral in the other. The direction of allelic effects was associated with allele frequency differences between the species: positive-effect alleles were often derived from the native species, whereas negative-effect alleles, at other loci, tended to originate from the non-native species. We conclude that ecological differentiation is governed and maintained by many loci with small, conditionally neutral effects. Conditional neutrality may result from differences in selection targets in the two habitats and provides hidden variation upon which selection can act. Polygenic architectures of adaptive differentiation are expected to be transient during lineage divergence and may therefore be unrelated to high genetic differentiation at the underlying loci.

Sign in / Sign up

Export Citation Format

Share Document