Using three-dimensional geometric morphometric and dental topographic analyses to infer the systematics and paleoecology of fossil treeshrews (Mammalia, Scandentia)

2020 ◽  
Vol 94 (6) ◽  
pp. 1202-1212
Author(s):  
Keegan R. Selig ◽  
Eric J. Sargis ◽  
Stephen G.B. Chester ◽  
Mary T. Silcox
Keyword(s):  
Evolutionary History ◽  
Effective Means ◽  
Three Dimensional ◽  
Dental Morphology ◽  
Geometric Morphometric ◽  
Second Molar ◽  
Morphometric Analyses ◽  
History Of ◽  
Dietary Ecology ◽  
Molar Morphology

AbstractTreeshrews are small, Indomalayan mammals closely related to primates. Previously, three-dimensional geometric morphometric analyses were used to assess patterns of treeshrew lower second molar morphology, which showed that the positions of molar landmarks covary with intraordinal systematics. Another analysis used dental topographic metrics to test patterns of functional dental morphology and found that molar curvature, complexity, and relief were an effective means for examining patterns of variation in treeshrew dietary ecology. Here, we build on these analyses by adding two fossil taxa, Prodendrogale yunnanica Qiu, 1986 from the Miocene of China and Ptilocercus kylin Li and Ni, 2016 from the Oligocene of China. Our results show that Pr. yunnanica had a dental bauplan more like that of a tupaiid than that of a ptilocercid, but that the extant tupaiids, including Tupaia and Dendrogale, are more similar to one another in this regard than any are to Prodendrogale. This is contrary to our expectations as Prodendrogale is hypothesized to be most closely related to Dendrogale. Ptilocercus kylin, which has been proposed to be the sister taxon of Pt. lowii Gray, 1848, is characterized by dental morphology like that of Pt. lowii in crest and cuspal position but is interpreted to have been more frugivorous. It has been claimed that Ptilocercus has undergone little morphological change through time. Our results suggest that Pt. kylin was more ecologically distinct from Pt. lowii than previously proposed, providing a glimpse into a more complex evolutionary history of the group than had been inferred.

scholarly journals Xiphosurid from the Tournaisian (Carboniferous) of Scotland confirms deep origin of Limuloidea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Russell D. C. Bicknell ◽  
Stephen Pates
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Horseshoe Crab ◽  
New Taxon ◽  
Geometric Morphometric ◽  
Lower Carboniferous ◽  
Morphometric Analyses ◽  
Lower Ordovician ◽  
Horseshoe Crabs ◽  
History Of

AbstractHorseshoe crabs are archetypal marine chelicerates with a fossil record extending from the Lower Ordovician to today. The major horseshoe crab groups are thought to have arisen in the middle to late Palaeozoic. Here we present the oldest known limuloid from the lower Carboniferous (Tournaisian stage, c. 350 million years ago) of Scotland: Albalimulus bottoni gen. et sp. nov. A comprehensive phylogenetic analysis supports the placement of A. bottoni as a representative of the extant family Limulidae and 100 million years older than any other limulid taxon. The use of geometric morphometric analyses corroborate the erection of the new taxon and illustrates the exploitation of morphospace by xiphosurids. This new taxon highlights the complex evolutionary history of xiphosurids and the importance of documenting these unique Palaeozoic individuals.

scholarly journals Origin of raptorial feeding in juvenile euarthropods revealed by a Cambrian radiodontan

2018 ◽  
Vol 5 (6) ◽  
pp. 863-869 ◽  
Author(s):  
Jianni Liu ◽  
Rudy Lerosey-Aubril ◽  
Michael Steiner ◽  
Jason A Dunlop ◽  
Degan Shu ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Feeding Habits ◽  
Phylogenetic Position ◽  
Early Developmental Stage ◽  
Rapid Rise ◽  
Juvenile Instar ◽  
History Of ◽  
Dietary Ecology ◽  
Chengjiang Biota ◽  
Early Developmental

Abstract The rapid rise of arthropods during the Cambrian quickly established some clades, such as the euarthropod stem-group called Radiodonta, as the dominant and most diverse predators in marine ecosystems. Recent discoveries have shown that the size and dietary ecology of radiodontans are far more diverse than previously thought, but little is known about the feeding habits of juveniles. Here, we document a very small (∼18-mm-long), near-complete specimen of the radiodontan Lyrarapax unguispinus from the early Cambrian Chengjiang Biota of China. This specimen is the smallest radiodontan individual known, representing a juvenile instar. Its adult-like morphology—especially the fully developed spinose frontal appendages and tetraradial oral cone—indicates that L. unguispinus was a well-equipped predator at an early developmental stage, similar to modern raptorial euarthropods, such as mantises, mantis shrimps and arachnids. This evidence, coupled with the basal phylogenetic position of radiodontans, confirms that raptorial feeding habits in juvenile euarthropods appeared early in the evolutionary history of the group.

scholarly journals Gaia: A Stereoscopic Census of Our Galaxy

2009 ◽  
Vol 5 (H15) ◽  
pp. 816-816
Author(s):  
T. Prusti
Keyword(s):  
Physical Properties ◽  
Elemental Composition ◽  
Observational Data ◽  
Evolutionary History ◽  
Three Dimensional ◽  
Subsequent Evolution ◽  
The Galaxy ◽  
History Of ◽  
Space Astrometry ◽  
Modern Astronomy

AbstractGaia is a space astrometry mission, a broad survey project following the measurement and operational principles of Hipparcos. It will help solving one of the most difficult yet deeply fundamental challenges in modern astronomy: to create an extraordinarily precise three-dimensional map of about one billion stars throughout our Galaxy and beyond. In the process, it will map their three-dimensional motions, which encode the origin and subsequent evolution of the Galaxy. Through comprehensive photometric and spectroscopic classification, it will provide the detailed physical properties of each star observed: characterising their luminosity, temperature, gravity, and elemental composition. This massive stellar census will provide the basic observational data to tackle an enormous range of important problems related to the origin, structure, and evolutionary history of our Galaxy.

scholarly journals Reassessment of the phylogenetic relationships of the late Miocene apes Hispanopithecus and Rudapithecus based on vestibular morphology

2021 ◽  
Vol 118 (5) ◽  
pp. e2015215118
Author(s):  
Alessandro Urciuoli ◽  
Clément Zanolli ◽  
Sergio Almécija ◽  
Amélie Beaudet ◽  
Jean Dumoncel ◽  
...  
Keyword(s):  
Late Miocene ◽  
Phylogenetic Relationships ◽  
Three Dimensional ◽  
Semicircular Canals ◽  
Great Apes ◽  
Great Ape ◽  
Ongoing Debate ◽  
Evolutionary Patterns ◽  
Geometric Morphometric ◽  
Morphometric Analyses

Late Miocene great apes are key to reconstructing the ancestral morphotype from which earliest hominins evolved. Despite consensus that the late Miocene dryopith great apes Hispanopithecus laietanus (Spain) and Rudapithecus hungaricus (Hungary) are closely related (Hominidae), ongoing debate on their phylogenetic relationships with extant apes (stem hominids, hominines, or pongines) complicates our understanding of great ape and human evolution. To clarify this question, we rely on the morphology of the inner ear semicircular canals, which has been shown to be phylogenetically informative. Based on microcomputed tomography scans, we describe the vestibular morphology of Hispanopithecus and Rudapithecus, and compare them with extant hominoids using landmark-free deformation-based three-dimensional geometric morphometric analyses. We also provide critical evidence about the evolutionary patterns of the vestibular apparatus in living and fossil hominoids under different phylogenetic assumptions for dryopiths. Our results are consistent with the distinction of Rudapithecus and Hispanopithecus at the genus rank, and further support their allocation to the Hominidae based on their derived semicircular canal volumetric proportions. Compared with extant hominids, the vestibular morphology of Hispanopithecus and Rudapithecus most closely resembles that of African apes, and differs from the derived condition of orangutans. However, the vestibular morphologies reconstructed for the last common ancestors of dryopiths, crown hominines, and crown hominids are very similar, indicating that hominines are plesiomorphic in this regard. Therefore, our results do not conclusively favor a hominine or stem hominid status for the investigated dryopiths.

scholarly journals Evaluation of Efficacy of Various Implants in Maxillary Arch Distalization - A Finite Element Analysis

2020 ◽  
Vol 10 (1) ◽  
pp. 44-54
Author(s):  
Sneha Sanap ◽  
Vinit Swami ◽  
Amol Patil ◽  
Shailesh Deshmukh ◽  
Veera Bhosale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Effective Means ◽  
Three Dimensional ◽  
Element Model ◽  
Class Ii ◽  
Maximum Amount ◽  
Element Analysis ◽  
Second Molar ◽  
Maxillary Arch

Introduction: Orthodontic correction of Angle’s class II molar relation has, for long, been one of the challenges in orthodontics, with various researchers attempting to correct the class II molar relationship by diverse methods. One of the techniques that has gained popularity in recent times is maxillary arch distalization by infrazygomatic screws and miniscrews. The objective of the study is to measure and compare the amount of maxillary arch distalization and its effects, on adjacent teeth, by varying the positions of mini-implants by Finite Element Analysis. Materials & Method: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. In this study, three models were prepared. Model-1: The (miniscrews) were placed between upper first and second premolar, and between second premolar and first molar bilaterally. Model-2: Infrazygomatic screws was placed between upper first and second molar bilaterally. Model-3: Infrazygomatic screws was placed on the mesio-buccal root of upper first molar bilaterally. The displacement of each tooth was calculated on x, y, and z axes when 200 gm of force was applied on each side. Result: Maximum amount of maxillary arch distalization was seen when infrazygomatic screws placed between upper first and second molar in model-2. Whereas maximum amount of maxillary arch intrusion and less distalization was observed when miniscrews placed between upper first premolar and second premolar and in between second premolar and upper first molar in model-1. The difference was statistically significant (p=0.005*). There was no bucco-palatal rotation of teeth observed among all three finite element models. Conclusion: Thus infrazygomatic screws and miniscrews are the effective means of maxillary arch distalization for the correction of Class II malocclusion.

scholarly journals A hominin first rib discovered at the Sterkfontein Caves, South Africa

2016 ◽  
Vol Volume 112 (Number 5/6) ◽  
Author(s):  
Gaokgatlhee Tawan ◽  
Daniel García-Martínez ◽  
Jennifer Eyre ◽  
Markus Bastir ◽  
Lee Berger ◽  
...  
Keyword(s):  
South Africa ◽  
South African ◽  
Fossil Record ◽  
Three Dimensional ◽  
Great Apes ◽  
Small Individual ◽  
Geometric Morphometric ◽  
First Rib ◽  
Morphometric Analyses ◽  
Fossil Hominin

Abstract First ribs – the first or most superior ribs in the thorax – are rare in the hominin fossil record, and when found, have the potential to provide information regarding the upper thorax shape of extinct hominins. Here, we describe a partial first rib from Member 4 of the Sterkfontein Caves, South Africa. The rib shaft is broken away, so only the head and neck are preserved. The rib is small, falling closest to small-bodied Australopithecus first ribs (AL 288-1 and MH1). Given that it was recovered near the StW 318 femur excavation, which also represents a small individual, we suggest that the two may be associated. Three-dimensional geometric morphometric analyses were used to quantify the rib fragment morphology and compare it to extant hominoid and other fossil hominin ribs. While only the proximal end is preserved, our analyses show that South African Australopithecus share derived features of the proximal first rib more closely resembling A. afarensis and later hominins than great apes.

scholarly journals Phylogeny and adaptation shape the teeth of insular mice

2016 ◽  
Vol 283 (1824) ◽  
pp. 20152820 ◽  
Author(s):  
Ronan Ledevin ◽  
Pascale Chevret ◽  
Guila Ganem ◽  
Janice Britton-Davidian ◽  
Emilie A. Hardouin ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Size Variation ◽  
Wood Mouse ◽  
Relative Role ◽  
Resource Exploitation ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Competition Level ◽  
History Of

By accompanying human travels since prehistorical times, the house mouse dispersed widely throughout the world, and colonized many islands. The origin of the travellers determined the phylogenetic source of the insular mice, which encountered diverse ecological and environmental conditions on the various islands. Insular mice are thus an exceptional model to disentangle the relative role of phylogeny, ecology and climate in evolution. Molar shape is known to vary according to phylogeny and to respond to adaptation. Using for the first time a three-dimensional geometric morphometric approach, compared with a classical two-dimensional quantification, the relative effects of size variation, phylogeny, climate and ecology were investigated on molar shape diversity across a variety of islands. Phylogeny emerged as the factor of prime importance in shaping the molar. Changes in competition level, mostly driven by the presence or absence of the wood mouse on the different islands, appeared as the second most important effect. Climate and size differences accounted for slight shape variation. This evidences a balanced role of random differentiation related to history of colonization, and of adaptation possibly related to resource exploitation.

Numerical simulation for evolutionary history of three-dimensional basin

1994 ◽  
Vol 15 (5) ◽  
pp. 435-446 ◽  
Author(s):  
Yi-rang Yuan ◽  
Wen-qia Wang ◽  
Dan-ping Yang ◽  
Yu-ji Han ◽  
Cheng-shun Yang
Keyword(s):  
Numerical Simulation ◽  
Evolutionary History ◽  
Three Dimensional ◽  
History Of

scholarly journals New insights into the earlier evolutionary history of epiphytic macrolichens

2021 ◽  
Author(s):  
Qiuxia Yang ◽  
Yanyan Wang ◽  
Robert Lucking ◽  
H. Thorsten Lumbsch ◽  
Xin Wang ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Evolutionary History ◽  
Terrestrial Ecosystems ◽  
Molecular Dating ◽  
Geometric Morphometric ◽  
New Family ◽  
Family Level ◽  
History Of ◽  
New Material ◽  
Geometric Morphometric Analysis

Lichens are well known as pioneer organisms colonizing bare surfaces such as rocks and therefore have been hypothesized to play a role in the early formation of terrestrial ecosystems. Given the rarity of fossil evidence, our understanding of the evolutionary history of lichen-forming fungi is primarily based on molecular dating approaches. These studies suggest extant clades of macrolichens diversified after the K-Pg boundary. Here we corroborate the mid-Mesozoic fossil Daohugouthallus ciliiferus as an epiphytic macrolichen that predates the K-Pg boundary by 100 Mys. Based on new material and geometric morphometric analysis, we demonstrate that the Jurassic fossil is morphologically most similar to Parmeliaceae, but cannot be placed in Parmeliaceae or other similar family-level clades forming macrolichens as these evolved much later. Consequently, a new family, Daohugouthallaceae, is proposed here to accommodate this fossil, which reveals macrolichens may have been diverse long before the Cenozoic diversification of extant lineages.

Morphological Variation of the Baka Pygmies’ Deciduous Second Molars 

2021 ◽  
Author(s):  
Petra G. Šimková ◽  
Gerhard W. Weber ◽  
Fernando Ramirez-Rozzi ◽  
Lotfi Slimani ◽  
Jérémy Sadoine ◽  
...  
Keyword(s):  
Distal Region ◽  
Dental Morphology ◽  
Second Molar ◽  
Natural Logarithm ◽  
Dental Crowns ◽  
Human Sample ◽  
Molar Morphology ◽  
South Americans ◽  
Deciduous Molars ◽  
General Size

Abstract The Baka pygmies are known for their short stature resulting from a reduced growth rate during infancy. They are peculiar also for their teeth erupt earlier than in any other African population, and their posterior dentition is larger than in non-pygmies. However, the Baka’s dental morphology, as several other aspects of their biology, is still understudied. In this study we explore the Baka’s upper and lower second deciduous molars variation in comparison to a human sample including Africans, Asians, Europeans, and South Americans by means of 3D geometric morphometrics. We analyzed both the outer and inner aspect of the dental crowns, as well as their general size based on the natural logarithm of centroid sizes. Our results show largely overlapping morphologies between populations, especially for the lower molars. The distal region of the second molars is the most variable, with the Baka’s lower second molars showing the most extreme range of variation for this aspect and in terms of crown height. Upper and lower second molars showed high morphological covariation (RV=0.82). The Baka and South Americans’ second molars were confirmed among the largest in our sample. Despite of the Baka’s particular growth pattern, long-lasting isolation and extreme dental variation, it is not possible to distinguish them from other populations on the basis of their second molar morphology only.

Sign in / Sign up

Export Citation Format

Share Document