Intraspecific variation and micro-macroevolution connection: illustration with the late Miocene genus Progonomys (Rodentia, Muridae)

Paleobiology ◽  
2010 ◽  
Vol 36 (4) ◽  
pp. 641-657 ◽  
Author(s):  
Vincent Lazzari ◽  
Jean-Pierre Aguilar ◽  
Jacques Michaux
Keyword(s):  
Intraspecific Variation ◽  
Late Miocene ◽  
Population Level ◽  
Geological Time ◽  
Tooth Morphology ◽  
Murine Rodents ◽  
Mammalian Teeth ◽  
Morphological Differences ◽  
Evo Devo ◽  
Rats And Mice

Recent progresses in our knowledge of mouse odontogenesis have enhanced rodent tooth morphology as a model for Evo-Devo studies. Deciphering the connection between macroevolution and microevolution, however, especially in the case of mammalian teeth, requires examples to illustrate how morphological differences among species, or higher taxa, can stem from population-level processes. In this paper we use paleontological material to study intraspecific variation of tooth morphology in the late Miocene species Progonomys clauzoni, over a short span of geological time in a restricted area. Progonomys is of particular interest as a stem genus of all murine rodents (Old World rats and mice). We use morphometrical and statistical methods to illustrate how change in the amplitude in variation at the population level through geological time is associated with the emergence of new characters. Some of these new characters, including functional ones, become fixed in parallel in distinct murine lineages. Nine million years ago, Progonomys clauzoni displayed variational properties of the developmental system shared by the Murinae, which can also explain some singular tooth characteristics that now are scattered among the diverse lineages. Further morphometric studies, however, are necessary to explain how the variety of cusp patterns observed in Progonomys clauzoni can be explained by developmental properties.

scholarly journals Ancylotherium pentelicum (Mammalia, Chalicotheriidae) from the late Miocene of Kerassia (Greece) and remarks on its intraspecific variability

2021 ◽  
Author(s):  
Panagiotis Kampouridis ◽  
Socrates J. Roussiakis ◽  
Ioannis X. Giaourtsakis ◽  
Nikolaos Kargopoulos ◽  
Georgia Svorligkou ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Intraspecific Variation ◽  
Late Miocene ◽  
Eastern Mediterranean ◽  
Intraspecific Variability ◽  
Individual Variability ◽  
The Other ◽  
Other Hand ◽  
Morphological Differences

AbstractThe first detailed description of Ancylotherium pentelicum (Gaudry and Lartet, 1856) from the late Miocene (Turolian) of Kerassia (Greece) is provided based on three metapodial elements. Potential intraspecific variability of this species in the Eastern Mediterranean has been previously discussed, but no decisive conclusions could be drawn. The present comparison of metapodial elements of A. pentelicum from Kerassia, Pikermi, Samos (Greece), Pinaryaka, Salihpaşalar (Turkey), Kiro Kuchuk (North Macedonia), and Hadjidimovo (Bulgaria) provides evidence for the existence of notable intraspecific variation in both the morphology and especially the size of the species. The morphological differences in the shape and occurrence of some metapodial articular facets are probably associated with the anticipated individual variability and not with sexual dimorphism. On the other hand, the notable metrical variability observed among metapodials of A. pentelicum may be indicative of sexual dimorphism, as has been previously documented in other chalicotheriids.

Development and Molecular Genetics of Marchantia polymorpha

2021 ◽  
Vol 72 (1) ◽  
Author(s):  
Takayuki Kohchi ◽  
Katsuyuki T. Yamato ◽  
Kimitsune Ishizaki ◽  
Shohei Yamaoka ◽  
Ryuichi Nishihama
Keyword(s):  
Model Organism ◽  
Land Plant ◽  
Marchantia Polymorpha ◽  
Annual Review ◽  
Publication Date ◽  
Molecular Tools ◽  
Genetic Redundancy ◽  
Morphological Differences ◽  
Evo Devo ◽  
Basal Position

Bryophytes occupy a basal position in the monophyletic evolution of land plants and have a life cycle in which the gametophyte generation dominates over the sporophyte generation, offering a significant advantage in conducting genetics. Owing to its low genetic redundancy and the availability of an array of versatile molecular tools, including efficient genome editing, the liverwort Marchantia polymorpha has become a model organism of choice that provides clues to the mechanisms underlying eco-evo-devo biology in plants. Recent analyses of developmental mutants have revealed that key genes in developmental processes are functionally well conserved in plants, despite their morphological differences, and that lineage-specific evolution occurred by neo/subfunctionalization of common ancestral genes. We suggest that M. polymorpha is an excellent platform to uncover the conserved and diversified mechanisms underlying land plant development. Expected final online publication date for the Annual Review of Plant Biology, Volume 72 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals IV. On the nature and limits of reptilian character in mammalian teeth

1888 ◽  
Vol 44 (266-272) ◽  
pp. 129-141 ◽  
Keyword(s):  
Geological Time ◽  
Mammalian Teeth

Approximations between reptiles and mammals have been recognised in many parts of the skeleton. They are most marked between certain genera and orders of the two classes. The oldest known fossil representatives of both groups certainly approximate closer towards each other in all known parts of skeletons than do the orders which survive; so it may be a legitimate induction that, in an earlier period of geological time, the characters of both groups were so blended, that there existed neither the modern reptile, which has specialised by losing mammalian attributes, nor the modern mammal, which has specialised by losing the skeletal characters which have come to be regarded as reptilian.

scholarly journals The first Miocene fossils of Lacerta cf.trilineata(Squamata, Lacertidae) with a comparative study of the main cranial osteological differences in green lizards and their relatives

2019 ◽  
Author(s):  
Andrej Čerňanský ◽  
Elena V. Syromyatnikova
Keyword(s):  
Comparative Study ◽  
Late Miocene ◽  
Fossil Record ◽  
Calibration Point ◽  
Lizard Species ◽  
Podarcis Muralis ◽  
Modern Species ◽  
Zootoca Vivipara ◽  
Morphological Differences ◽  
Important Evidence

AbstractWe here describe the first fossil remains of a green lizardof theLacertagroup from the late Miocene (MN 13) of the Solnechnodolsk locality in southern European Russia. This region of Europe is crucial for our understanding of the paleobiogeography and evolution of these middle-sized lizards. Although this clade has a broad geographical distribution across the continent today, its presence in the fossil record has only rarely been reported. In contrast to that, the material described here is abundant, consists of a premaxilla, maxillae, frontals, parietals, jugals, quadrate, pterygoids, dentaries and vertebrae. The comparison of these elements to all extant green lizard species shows that these fossils are indistinguishable fromLacerta trilineata. Thus, they form the first potential evidence of the occurrence of this species in the Miocene. This may be also used as a potential calibration point for further studies. Together with other lizard fossils, Solnechnodolsk shows an interesting combination of survivors and the dawn of modern species. This locality provides important evidence for the transition of an archaic Miocene world to the modern diversity of lizards in Europe. In addition, this article represents a contribution to the knowledge of the comparative osteological anatomy of the selected cranial elements in lacertid. This study gives special emphasis to the green lizards, but new data are also presented for related taxa, e.g.,Timon lepidus, Podarcis muralisorZootoca vivipara. Although the green lizards include several cryptic species for which determination based on isolated osteological material would be expected to be difficult, our comparisons show several important morphological differences.

scholarly journals New data to the knowledge of Gaeolaelaps mites (Acari: Mesostigmata: Laelapidae)

Acarologia ◽  
2018 ◽  
Vol 58 (3) ◽  
pp. 710-734
Author(s):  
Alireza Nemati ◽  
Dariusz J. Gwiazdowicz ◽  
Arsalan Khalili-Moghadam
Keyword(s):  
Intraspecific Variation ◽  
Morphological Changes ◽  
Morphological Difference ◽  
Morphological Characters ◽  
Type Material ◽  
Taxonomic Confusion ◽  
Morphological Differences ◽  
Distinguishing Features

The present paper is devoted to the study of some morphological changes in the laelapid genus Gaeolaelaps, based on observations on G. queenslandicus (Womersley, 1956), G. angustus (Karg, 1965) and G. tripodiger (Berlese, 1916) [new comb]. According to our observations on the type material of G. angustus, previous redescription of G. queenslandicus (sensu Costa 1966, based on holotype), specimens of this species from Australia and numerous specimens from Iran identified as either G. angustus or G. queenslandicus, notable variations were observed in some morphological characters, which had previously been considered as distinguishing features between the two species. Our analysis indicates that these morphological differences represent intraspecific variation, and therefore the two species names are synonyms. Furthermore, observation of type material of G. tripodiger shows that the two first mentioned species are junior synonyms of G. tripodiger. The original descriptions of G. trifurcatus (Wang and Li, 1965) [new comb.] and G. trifurcatoides (Yan and Ma, 1999) ([new comb.] show no authentic morphological difference from G. tripodiger and those are also junior synonyms of the later. The oldest available name for this species is Gaeolaelaps tripodiger. However, that name is almost unknown, and to use it as a valid name would cause taxonomic confusion. Therefore, we continue to use the widely known name Gaeolaelaps queenslandicus for this species, in the interests of stability.

scholarly journals Early Late Miocene Murine Rodents from the Upper Part of the Nagri Formation, Siwalik Group, Pakistan, with a new fossil calibration point for the Tribe Apodemurini (Apodemus/Tokudaia)

2017 ◽  
Vol 73 (1-2) ◽  
pp. 197-212 ◽  
Author(s):  
Yuri Kimura ◽  
Lawrence J. Flynn ◽  
Louis L. Jacobs
Keyword(s):  
Late Miocene ◽  
Middle Miocene ◽  
Northern Pakistan ◽  
Calibration Point ◽  
Fossil Calibration ◽  
Murine Rodents ◽  
Siwalik Group ◽  
Fossil Genus ◽  
Early Late ◽  
A New Species

Abstract The early late Miocene is an interval of increased diversification for murine rodents. Whereas the genus Progonomys became widespread throughout Eurasia by 10 Ma, it appears from the known paleontological record that southern Asia is the arena of evolution and diversification at the base of the Murinae. The Siwalik fossil record of the Potwar Plateau in northern Pakistan preserves fossil evidence relevant to unraveling this history. Murine rodents are recorded there throughout the middle Miocene, and diversification began in Siwalik assemblages before 11 Ma. The well-established Progonomys and Karnimata lineages were already present between 11 and 10 Ma, and these represent extant murine crown groups. Here we document diversity in Siwalik murines dating to 10.5 to 10.1 Ma, and clarify their recognition by naming a new species of Karnimata and referring specimens of Progonomys from this interval to P. hussaini. In addition, we define at least two other uncommon murine species that coexist with them. One of these is an early record of Parapodemus, a fossil genus of Tribe Apodemurini, which constitutes a calibration point for the Apodemus/Tokudaia split. Together, these fossil taxa provide further evidence bearing on the major split among murines leading to the clades Murini and Arvicanthini.

Heteropoda species from limestone caves in Laos (Araneae: Sparassidae: Heteropodinae)

Zootaxa ◽  
2009 ◽  
Vol 2143 (1) ◽  
pp. 1-23 ◽  
Author(s):  
STEFFEN BAYER ◽  
PETER JÄGER
Keyword(s):  
Intraspecific Variation ◽  
Cave System ◽  
Morphological Differences ◽  
First Time

Two new Heteropoda species from Laos are described, Heteropoda steineri sp. nov. (male, female) from the Xe Bangfai cave system in Khammouan Province, and Heteropoda aemulans sp. nov. (male, female) from caves close to Vang Vieng in Vientiane Province. Two further species, Heteropoda maxima Jäger, 2001 from Khammouan Province and Heteropoda simplex Jäger and Ono, 2000 from northern Laos and Japan, are recorded. Heteropoda simplex is recorded for the first time from Laos, the female is described for the first time. Main morphological differences between species are recognised from copulatory organs and colouration. Intraspecific variation is illustrated for all species.

scholarly journals Morphological variation among populations of Hemigrammus coeruleus (Characiformes: Characidae) in a Negro River tributary, Brazilian Amazon

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Henrique Lazzarotto ◽  
Thiago Barros ◽  
José Louvise ◽  
Érica Pellegrini Caramaschi
Keyword(s):  
Morphological Variation ◽  
Phenotypic Variation ◽  
Population Level ◽  
Brazilian Amazon ◽  
Additional Species ◽  
Geometric Morphometric ◽  
Blackwater River ◽  
Ecological Selection ◽  
Negro River ◽  
Morphological Differences

ABSTRACT We explored patterns of phenotypic variation in Hemigrammus coeruleus from the Unini River basin, a blackwater river in the Brazilian Amazon. Geometric morphometrics was used to evaluate variation in body shape among populations from four tributaries (UN2-UN5). We found no evidence for sexual dimorphism in body size and shape. However, morphological differences among populations were detected as the analyses recovered significant groups corresponding to each sub-basin, with some overlap among them. The populations from UN2, UN3 and UN5 had more elongate bodies than fish from UN4. The most morphologically divergent population belonged to UN4, the tributary with the most divergent environmental conditions and the only one with seasonally-muddy waters. The morphological variation found among these populations is likely due to phenotypic plasticity or local adaptation, arising as a product of divergent ecological selection pressures among sub-basins. This work constitutes one of the first to employ a population-level geometric morphometric approach to assess phenotypic variation in Amazonian fishes. This method was able to distinguish subtle differences in body morphology, and its use with additional species can bring novel perspectives on the evaluation of general patterns of phenotypic differentiation in the Amazon.

Randomness in Evolution

2013 ◽  
Author(s):  
John Tyler Bonner
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Biological Diversity ◽  
Large Mammals ◽  
Geological Time ◽  
Central Tenet ◽  
Morphological Differences

This book challenges a central tenet of evolutionary biology. The book makes the bold and provocative claim that some biological diversity may be explained by something other than natural selection. The book makes an argument for the underappreciated role that randomness—or chance—plays in evolution. Due to the tremendous and enduring influence of Darwin's natural selection, the importance of randomness has been to some extent overshadowed. The book shows how the effects of randomness differ for organisms of different sizes, and how the smaller an organism is, the more likely it is that morphological differences will be random and selection may not be involved to any degree. The book then traces the increase in size and complexity of organisms over geological time, and looks at the varying significance of randomness at different size levels, from microorganisms to large mammals. The book also discusses how sexual cycles vary depending on size and complexity, and how the trend away from randomness in higher forms has even been reversed in some social organisms.

Redescription of two species and proposal of a new synonym in the genus Mycotretus Lacordaire, 1842 (Coleoptera: Erotylidae: Tritomini) 

Zootaxa ◽  
2017 ◽  
Vol 4282 (1) ◽  
pp. 147 ◽  
Author(s):  
ITALO SALVATORE DE CASTRO PECCI-MADDALENA ◽  
CRISTIANO LOPES-ANDRADE
Keyword(s):  
Intraspecific Variation ◽  
Geographic Distribution ◽  
Phylogenetic Signal ◽  
Taxonomic Revision ◽  
Junior Synonym ◽  
Female Genitalia ◽  
Male And Female ◽  
New Synonym ◽  
Morphological Differences ◽  
First Descriptions

Mycotretus Lacordaire, 1842 is a Neotropical genus of beetles, being the second most speciose genus within Erotylidae. The older descriptions of Mycotretus species are anecdotal and none include information on male and female genitalia, which can have great taxonomic value. Our objective in the present work is to redescribe Mycotretus chilensis Crotch, 1876 and Mycotretus trifasciatus Guérin, 1956 providing the first descriptions of their mouthparts, metendosternite, male and female terminalia, as well as new data on their geographic distribution and host fungi. Additionally, the lectotype of M. chilensis is designated and Mycotretus bicinctus Guérin, 1949 is proposed as a new junior synonym of M. chilensis. Both M. chilensis and M. trifasciatus have great intraspecific variation and are sympatric or syntopic in a few localities. We conclude that morphological differences of the penial flagellum and the metendosternite can be used to diagnose species and may also have phylogenetic signal for Mycotretus species. The present work is our first step in an ongoing taxonomic revision of the genus Mycotretus. 

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