Evolutionary Patterns and Processes in Ferns

1979 ◽  
Vol 69 (1) ◽  
pp. 16
Author(s):  
David B. Lellinger ◽  
J. D. Lovis
Keyword(s):  
Evolutionary Patterns ◽  
Patterns And Processes

Redescription of Mastigias papua (Scyphozoa, Rhizostomeae) with designation of a neotype and recognition of two additional species

Zootaxa ◽  
2018 ◽  
Vol 4457 (4) ◽  
pp. 520 ◽  
Author(s):  
MARIANA ROCHA DE SOUZA ◽  
MICHAEL N DAWSON
Keyword(s):  
Pacific Islands ◽  
Parallel Evolution ◽  
Morphological Characters ◽  
The Philippines ◽  
Type Specimens ◽  
Additional Species ◽  
Evolutionary Patterns ◽  
Molecular Analyses ◽  
Taxonomic Approach ◽  
Patterns And Processes

Mastigias, the ‘golden’ or ‘spotted’ jellyfish, is distributed throughout the Indo-Pacific. Specimens are identified routinely as Mastigias papua, although eight species were described historically, and molecular analyses evince at least three phylogenetic species. Understanding species diversity in Mastigias has become a priority because of its growing relevance in studies of boom-bust dynamics related to environmental change, cryptic species, local adaptation, parallel evolution, and peripatric speciation. However, species delimitation and identification are inhibited by a dearth of type specimens for most species, including M. papua. We address these issues by resampling Mastigias from the type locality in Waigeo, West Papua, as well as in the Philippines, and by comparing cytochrome c oxidase subunit I and up to 34 morphological characters of 268 Mastigias specimens from surrounding regions in the Indo-Pacific. We also gathered data from the historical descriptions of the eight species of Mastigias to estimate the identity of the two other currently revealed clades. Using this integrative taxonomic approach, we re-describe Mastigias papua as endemic to the tropical western Pacific islands (including Papua, Palau, Enewetak) and designate a neotype for the species. Additionally, based on morphological similarity and geographic overlap, we identified a second clade most probably as M. albipunctatus (from Japan, Komodo, Berau and Philippines) and a third clade tentatively as either M. andersoni or M. ocellatus. This study highlights the benefits of combining molecular analyses, samples from type locations, traditional descriptions and statistical analyses of morphological variation in systematic studies, and the concomitant potential of such studies to increase understanding of evolutionary patterns and processes in Scyphozoa.

Morphological evolution of the bivalvePtychomyathrough the Lower Cretaceous of Argentina

Paleobiology ◽  
2018 ◽  
Vol 44 (1) ◽  
pp. 101-117
Author(s):  
Pablo S. Milla Carmona ◽  
Darío G. Lazo ◽  
Ignacio M. Soto
Keyword(s):  
Time Series ◽  
Morphological Variation ◽  
Morphological Evolution ◽  
The Other ◽  
Upward Trend ◽  
Shell Size ◽  
Evolutionary Patterns ◽  
Upper Hauterivian ◽  
Patterns And Processes ◽  
Early Late

AbstractThe complex morphological evolution of the bivalvePtychomyathroughout the well-studied Agrio Formation in the Neuquén Basin (west-central Argentina, lower/upper Valanginian–lowest Barremian) constitutes an ideal opportunity to study evolutionary patterns and processes occurring at geological timescales. Ptychomyais represented in this unit by four species, the morphological variation of which needs to be temporally assessed to obtain a thorough picture of the evolution of the group. Here we use geometric morphometrics to measure variation in shell outline, ribbing pattern, and shell size in these species. We bracket the ages of our samples using a combination of ammonoid biostratigraphy and absolute ages and study the anagenetic pattern of evolution of each trait by means of paleontological time-series analysis and change tracking. We find that evolution inPtychomyais mostly speciational, as the majority of traits show stasis, with the exceptions of shell size inP. coihuicoensisand shell outline inP. windhauseni, which seem to evolve directionally toward larger and higher shells, respectively.Ptychomyadisplays changes in its average morphology and disparity, which are the result of a mixture of taxonomic turnover and mosaic evolution of traits. Pulses of speciation would have been triggered by ecological opportunity, as they occur during the recovery of shallow-burrowing bivalve faunas after dysoxic events affecting the basin. On the other hand, the presence of directional patterns of evolution inP. coihuicoensisandP. windhauseniseems to be the result of a general shallowing-upward trend observed in the basin during the upper Hauterivian–lowest Barremian, as opposed to the cyclical paleoenvironmental stability inferred for the early/late Valanginian–early Hauterivian, which would have prompted stasis inP. koeneniandP. esbelta.

scholarly journals Universal rules of life: metabolic rates, biological times and the equal fitness paradigm

2021 ◽  
Author(s):  
Joseph Burger ◽  
Chen Hou ◽  
Charles Hall ◽  
James Brown
Keyword(s):  
Structure And Function ◽  
The Other ◽  
Metabolic Rates ◽  
Synthetic Theory ◽  
Evolutionary Patterns ◽  
Single Origin ◽  
The One ◽  
Patterns And Processes ◽  
And Function ◽  
Dynamics Of Populations

Here we review and extend the equal fitness paradigm (EFP) as an important step in developing and testing a synthetic theory of ecology and evolution based on energy and metabolism. The EFP states that all organisms are equally fit at steady state, because they allocate the same quantity of energy, ~22.4 kJ/g/generation to production of offspring. On the one hand, the EFP may seem tautological, because equal fitness is necessary for the origin and persistence of biodiversity. On the other hand, the EFP reflects universal laws of life: how biological metabolism – the uptake, transformation and allocation of energy – links ecological and evolutionary patterns and processes across levels of organization from: i) structure and function of individual organisms, ii) life history and dynamics of populations, iii) interactions and coevolution of species in ecosystems. The physics and biology of metabolism have facilitated the evolution of millions of species with idiosyncratic anatomy, physiology, behavior and ecology but also with many shared traits and tradeoffs that reflect the single origin and universal rules of life.

scholarly journals The systematic relationships and biogeographic history of ornithischian dinosaurs

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1523 ◽  
Author(s):  
Clint A. Boyd
Keyword(s):  
North America ◽  
South America ◽  
Wide Distribution ◽  
Sister Taxon ◽  
Evolutionary Patterns ◽  
Biogeographic History ◽  
Early Diversification ◽  
Systematic Relationships ◽  
Patterns And Processes ◽  
Comprehensive Framework

The systematic relationships of taxa traditionally referred to as ‘basal ornithopods’ or ‘hypsilophodontids’ remain poorly resolved since it was discovered that these taxa are not a monophyletic group, but rather a paraphyletic set of neornithischian taxa. Thus, even as the known diversity of these taxa has dramatically increased over the past two decades, our knowledge of their placement relative to each other and the major ornithischian subclades remained incomplete. This study employs the largest phylogenetic dataset yet compiled to assess basal ornithischian relationships (255 characters for 65 species level terminal taxa). The resulting strict consensus tree is the most well-resolved, stratigraphically consistent hypothesis of basal ornithischian relationships yet hypothesized. The only non-iguanodontian ornithopod (=basal ornithopod) recovered in this analysis isHypsilophodon foxii. The majority of former ‘hypsilophodontid’ taxa are recovered within a single clade (Parksosauridae) that is situated as the sister-taxon to Cerapoda. The Parksosauridae is divided between two subclades, the Orodrominae and the Thescelosaurinae. This study does not recover a clade consisting of the Asian taxaChangchunsaurus,Haya, andJeholosaurus(=Jeholosauridae). Rather, the former two taxa are recovered as basal members of Thescelosaurinae, while the latter taxon is recovered in a clade withYueosaurusnear the base of Neornithischia.The endemic South American clade Elasmaria is recovered within the Thescelosaurinae as the sister taxon toThescelosaurus. This study supports the origination of Dinosauria and the early diversification of Ornithischia within Gondwana. Neornithischia first arose in Africa by the Early Jurassic before dispersing to Asia before the late Middle Jurassic, where much of the diversification among non-cerapodan neornithischians occurred. Under the simplest scenario the Parksosauridae originated in North America, with at least two later dispersals to Asia and one to South America. However, when ghost lineages are considered, an alternate dispersal hypothesis has thescelosaurines dispersing from Asia into South America (via North America) during the Early Cretaceous, then back into North America in the latest Cretaceous. The latter hypothesis may explain the dominance of orodromine taxa prior to the Maastrichtian in North America and the sudden appearance and wide distribution of thescelosaurines in North America beginning in the early Maastrichtian. While the diversity of parksosaurids has greatly increased over the last fifteen years, a ghost lineage of over 40 myr is present between the base of Parksosauridae and Cerapoda, indicating that much of the early history and diversity of this clade is yet to be discovered. This new phylogenetic hypothesis provides a comprehensive framework for testing further hypotheses regarding evolutionary patterns and processes within Ornithischia.

scholarly journals Vertebrate palaeontology of Australasia into the twenty-first century

2011 ◽  
Vol 7 (6) ◽  
pp. 804-806 ◽  
Author(s):  
Jacqueline M. T. Nguyen ◽  
Martyna Molak ◽  
Karen H. Black ◽  
Erich M. G. Fitzgerald ◽  
Kenny J. Travouillon ◽  
...  
Keyword(s):  
Western Australia ◽  
First Century ◽  
Vertebrate Evolution ◽  
Dental Microwear ◽  
Evolutionary Patterns ◽  
New Techniques ◽  
Vertebrate Palaeontology ◽  
Technological Advances ◽  
Patterns And Processes ◽  
The University

The 13th Conference on Australasian Vertebrate Evolution Palaeontology and Systematics (CAVEPS) took place in Perth, Western Australia, from 27 to 30 April 2011. This biennial meeting was jointly hosted by Curtin University, the Western Australian Museum, Murdoch University and the University of Western Australia. Researchers from diverse disciplines addressed many aspects of vertebrate evolution, including functional morphology, phylogeny, ecology and extinctions. New additions to the fossil record were reported, especially from hitherto under-represented ages and clades. Yet, application of new techniques in palaeobiological analyses dominated, such as dental microwear and geochronology, and technological advances, including computed tomography and ancient biomolecules. This signals a shift towards increased emphasis in interpreting broader evolutionary patterns and processes. Nonetheless, further field exploration for new fossils and systematic descriptions will continue to shape our understanding of vertebrate evolution in this little-studied, but most unusual, part of the globe.

scholarly journals Rates of ecomorphological trait evolution in passerine bird clades are independent of age

2020 ◽  
Vol 129 (3) ◽  
pp. 543-557
Author(s):  
Anna G Phillips ◽  
Till Töpfer ◽  
Katrin Böhning-Gaese ◽  
Susanne A Fritz
Keyword(s):  
Passerine Bird ◽  
Evolutionary Patterns ◽  
Trait Evolution ◽  
Best Fitting ◽  
Adaptive Radiations ◽  
Divergence Pattern ◽  
Patterns And Processes ◽  
The Relationship ◽  
Fitting Model ◽  
Key Innovations

Abstract Although the links between species richness and diversification rates with clade age have been studied extensively, few studies have investigated the relationship between the rates of trait evolution and clade age. The rate of morphological trait evolution has repeatedly been shown to vary through time, as expected, for example, for adaptive radiations, but the strength and sources of this variation are not well understood. We compare the relationship between the rates of trait evolution and clade age across eight monophyletic clades of passerine birds by investigating ecomorphological traits, i.e. morphological traits that influence the ecology of the species directly. We study the ecomorphological divergence pattern using analyses of the disparity through time and determine the best-fitting model of evolution for each trait in each clade. We find no support for a consistent dependence of evolutionary rates on clade age across wing, tail, tarsus and beak shape in our eight clades and also show that early burst models of trait evolution are rarely the best-fitting models within these clades. These results suggest that key innovations or adaptive radiations might be less common evolutionary patterns and processes than generally thought or might depend on the taxonomic level investigated.

scholarly journals Phylogenetic taxonomy and classification of the Crinoidea (Echinodermata)

2017 ◽  
Vol 91 (4) ◽  
pp. 829-846 ◽  
Author(s):  
David F. Wright ◽  
William I. Ausich ◽  
Selina R. Cole ◽  
Mark E. Peter ◽  
Elizabeth C. Rhenberg
Keyword(s):  
Phylogenetic Relationships ◽  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Major Goal ◽  
Evolutionary Patterns ◽  
Phylogenetic Taxonomy ◽  
Phylogenetic Perspective ◽  
Phylogenetic Hypotheses ◽  
Patterns And Processes

AbstractA major goal of biological classification is to provide a system that conveys phylogenetic relationships while facilitating lucid communication among researchers. Phylogenetic taxonomy is a useful framework for defining clades and delineating their taxonomic content according to well-supported phylogenetic hypotheses. The Crinoidea (Echinodermata) is one of the five major clades of living echinoderms and has a rich fossil record spanning nearly a half billion years. Using principles of phylogenetic taxonomy and recent phylogenetic analyses, we provide the first phylogeny-based definition for the Clade Crinoidea and its constituent subclades. A series of stem- and node-based definitions are provided for all major taxa traditionally recognized within the Crinoidea, including the Camerata, Disparida, Hybocrinida, Cladida, Flexibilia, and Articulata. Following recommendations proposed in recent revisions, we recognize several new clades, including the Eucamerata Cole 2017, Porocrinoidea Wright 2017, and Eucladida Wright 2017. In addition, recent phylogenetic analyses support the resurrection of two names previously abandoned in the crinoid taxonomic literature: the Pentacrinoidea Jaekel, 1918 and Inadunata Wachsmuth and Springer, 1885. Last, a phylogenetic perspective is used to inform a comprehensive revision of the traditional rank-based classification. Although an attempt was made to minimize changes to the rank-based system, numerous changes were necessary in some cases to achieve monophyly. These phylogeny-based classifications provide a useful template for paleontologists, biologists, and non-experts alike to better explore evolutionary patterns and processes with fossil and living crinoids.

Testing the Darwinian legacy of the Cambrian radiation using trilobite phylogeny and biogeography

1999 ◽  
Vol 73 (2) ◽  
pp. 176-181 ◽  
Author(s):  
Bruce S. Lieberman
Keyword(s):  
Early Cambrian ◽  
Evolutionary Patterns ◽  
Earth History ◽  
Tectonic Events ◽  
Biological Meaning ◽  
History Of ◽  
Cambrian Radiation ◽  
Special Rules ◽  
Late Neoproterozoic ◽  
Patterns And Processes

Since the publication of Darwin (1859), the biological meaning of the Cambrian radiation has been debated. Most commentators agree, however, that the Cambrian radiation is fundamentally a time of major metazoan cladogenesis. In and of itself this does not necessarily mean that unique evolutionary processes operated during the Cambrian radiation. Phylogenetic analysis has been used to study the tempo of speciation during the radiation, and thus far there is no need to invoke special rules relating to the tempo of evolution. Instead, what seems unique about the Cambrian radiation is its place as an important episode in the history of life—that is, as the first major radiation of the Metazoa. Although the tempo of evolution during the Cambrian radiation may not have been uniquely high, there were largely unique tectonic events that transpired during the late Neoproterozoic and Early Cambrian, such as extensive cratonic fragmentation. Biogeographic analysis of Early Cambrian olenelloid trilobites reveals that these tectonic events powerfully influenced evolutionary and distributional patterns in this diverse and abundant trilobite group. This emphasizes the importance of physical earth history in generating evolutionary patterns. In the general study of macroevolutionary patterns and processes, earth history phenomena emerge as powerful forces influencing the history of life and provide insights into evolution that can best be inferred by paleontological data.

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