scholarly journals A high-resolution growth series of Tyrannosaurus rex obtained from multiple lines of evidence

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9192 ◽  
Author(s):  
Thomas D. Carr

Background During the growth of complex multicellular organisms, chronological age, size and morphology change together in a hierarchical and coordinated pattern. Among extinct species, the growth of Tyrannosaurus rex has received repeated attention through quantitative analyses of relative maturity and chronological age. Its growth series shows an extreme transformation from shallow skulls in juveniles to deep skulls in adults along with a reduction in tooth count, and its growth curve shows that T. rex had a high growth rate in contrast to its closest relatives. However, separately, these sets of data provide an incomplete picture of the congruence between age, size, and relative maturity in this exemplar species. The goal of this work is to analyze these data sets together using cladistic analysis to produce a single hypothesis of growth that includes all of the relevant data. Methods The three axes of growth were analyzed together using cladistic analysis, based on a data set of 1,850 morphological characters and 44 specimens. The analysis was run in TNT v.1.5 under a New Technology search followed by a Traditional search. Correlation tests were run in IBM SPSS Statistics v. 24.0.0.0. Results An initial analysis that included all of the specimens recovered 50 multiple most parsimonious ontograms a series of analyses identified 13 wildcard specimens. An analysis run without the wildcard specimens recovered a single most parsimonious tree (i.e., ontogram) of 3,053 steps. The ontogram is composed of 21 growth stages, and all but the first and third are supported by unambiguously optimized synontomorphies. T. rex ontogeny can be divided into five discrete growth categories that are diagnosed by chronological age, morphology, and, in part, size (uninformative among adults). The topology shows that the transition from shallow to deep skull shape occurred between 13 and 15 years of age, and the size of the immediate relatives of T. rex was exceeded between its 15th and 18th years. Although size and maturity are congruent among juveniles and subadults, congruence is not seen among adults; for example, one of the least mature adults (RSM 2523.8) is also the largest and most massive example of the species. The extreme number of changes at the transition between juveniles and subadults shows that the ontogeny of T. rex exhibits secondary metamorphosis, analogous to the abrupt ontogenetic changes that are seen at sexual maturity among teleosts. These results provide a point of comparison for testing the congruence between maturity and chronological age, size, and mass, as well as integrating previous work on functional morphology into a rigorous ontogenetic framework. Comparison of the growth series of T. rex with those of outgroup taxa clarifies the ontogenetic trends that were inherited from the common ancestor of Archosauriformes.

Zootaxa ◽  
2012 ◽  
Vol 3238 (1) ◽  
pp. 39 ◽  
Author(s):  
FELIPE LORENZ SIMÕES ◽  
AUGUSTO FERRARI ◽  
JOCÉLIA GRAZIA

The genus Elsiella Froeschner, 1981 is validated based on the analysis of a recently found male specimen of E. plana(Walker, 1867). A cladistic analysis comprising a data set of 40 morphological characters and 22 taxa, including the generaElsiella, Serdia Stål, Similliserdia Fortes & Grazia, Neotibilis Grazia & Barcellos, and Tibilis Stål, was performed. Elsiellaplana is redescribed and illustrated. Maps are provided for Elsiella and Serdia with biogeographical considerations for Serdia.


1995 ◽  
Vol 43 (6) ◽  
pp. 557 ◽  
Author(s):  
MS Springer ◽  
LJ Hollar ◽  
JAW Kirsch

Andersen's 1912 monograph on megachiropterans remains the definitive work on the systematics of this group. Andersen argued that the Macroglossinae, containing the eonycterine and notopterine sections, are a monophyletic sister-group to other fruitbats (i.e. Andersen's Rousettus, Cynopterus and Epomophorus sections). Two recent molecular studies (DNA hybridisation and restriction mapping of ribosomal cistrons), as well as an analysis of female reproductive characters, challenge the monophyly of the Macroglossinae and several of Andersen's other conclusions such as the phylogenetic position of Nyctimene. We performed a cladistic analysis on 36 morphological characters, including 33 that were gleaned from Andersen, to determine whether phylogenetic hypotheses based on modem phylogenetic methods are in agreement with Andersen's original conclusions and to compare morphological and molecular phylogenetic hypotheses. Minimum-length trees based on parsimony are largely consistent with Andersen and support (1) a monophyletic Macroglossinae, within which the eonycterine section is paraphyletic with respect to a monophyletic notopterine section, (2) a monophyletic Cynopterus section, excepting the exclusion of Myonycteris, (3) a monophyletic Epomophorus section, excepting the exclusion of Plerotes, and (4) a paraphyletic Rousettus section, with several of the Rousettus-like forms branching off near the base of the tree. Bootstrapping analyses on a reduced data-set that included taxa shared in common with the DNA hybridisation study did not provide strong support (greater than or equal to 95%) for any clades but did provide moderate support (greater than or equal to 70) for several clades, including a monophyletic Macroglossinae. These findings are in marked contrast to the DNA hybridisation phylogeny. A high index of between-data-set incongruence is further evidence for the clash between DNA hybridisation and morphology. A phylogenetic framework was constructed on the basis of morphological data and DNA hybridisation data using a criterion of moderate support and shows little resolution, whereas employing a criterion of strong support produced a framework resolving several additional nodes. One implication of this framework is that characteristic macroglossine features such as a long tongue with a thick carpet of filiform papillae have evolved independently on several occasions (or evolved once and were lost several times). Rates of character evolution for the morphological characters employed in our analysis were calculated using divergence times estimated from DNA hybridisation data. Rates have apparently been fastest in the interior branches, and slower along the external branches, which suggests an early adaptive radiation in the history of fruitbats.


1990 ◽  
Vol 64 (2) ◽  
pp. 255-277 ◽  
Author(s):  
B. D. E. Chatterton ◽  
D. J. Siveter ◽  
G. D. Edgecombe ◽  
A. S. Hunt

Up to four discrete protaspid larval stages are described for calymenid trilobites of Ordovician to Devonian age. The earliest growth stages are nonadult-like planktonic protaspides; later protaspides are adult-like and benthonic. In contrast, the related homalonotid trilobites apparently lack planktonic protaspides, but have up to two large benthonic protaspid stages that are similar in form to calymenid benthonic protaspides. These differences in life history patterns between these families are reflected in their paleobiogeographic distributions. Calymenids werre widely dispersed from Ordovician to Devonian times, both being common in warm, low latitude provinces (particularly from the Late Ordovician onwards) and well represented in cooler, higher latitude regions. The paleogeographic distribution of the homalonotids during the Ordovician (Arenig to the Ashgill) was concentrated in high paleolatitudes, with only a few forms occurring at low paleolatitudes (often in deeper, cooler environments?). Both families survived the Ordovician–Silurian mass extinction, with the calymenids again being widely dispersed but the homalonotids being best represented in the cool-water Malvinokaffric Province and in other regions where they are largely restricted to clastic facies.So few complete growth series of calymenine trilobites are known that it is unlikely that the ontogenies of taxa that form parts of ancestor–descendant clades can be identified. However, some evidence for heterochronic, particularly paedomorphic (neotenic), evolution is suggested for larval stages of members of both the Calymenidae and the Homalonotidae. Such possible neotenic evolution leading to very large planktonic larval stages of calymenid trilobites during the Devonian could have enhanced dispersal during a period of widespread warm and equable climates. Comparisons of homalonotid protaspides with equivalent stages of calymenids support the close relationship of these families within the Calymenina. A data matrix based upon characters of protaspides of two calymenine trilobites (Flexicalymene Shirley, 1936, and Brongniartella Reed, 1918) and eight other trilobites, belonging to the Phacopina (Calyptaulax), Cheirurina (Physemataspis and Hyrokybe), Proetida (Scharyia), Lichida (Acanthopyge), Odontopleurida (Diacanthaspis), Corynexochida (Bathyuriscus), and Ptychopariida (Crassifimbra) was subjected to cladistic analysis using the parsimony program “Hennig 86.” The shortest length cladogram produced is consistent with the inclusion of the Homalonotidae in the Calymenina, and inclusion of the Calymenina in the order Phacopida. “Cheirurina” is the paraphyletic “stem group” of Phacopina. The hypothesis that Lonchocephalidae is most closely related to part of post-Cambrian Phacopida is poorly supported by protaspid characters.


1995 ◽  
Vol 73 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Zhi-Qiang Zhang

Two morphological data sets for eight trombidioid genera (Acari: Parasitengona) were analyzed separately and in combination using cladistic methods. One data set comprised 15 adult morphological characters, whereas the other comprised 29 larval morphological characters. Analyzed separately, the data on adults produced five equally parsimonious trees and the data on larvae produced three equally parsimonious trees. Analyses of both data sets revealed two distinct clades in Trombidiidae: clade A (Podothrombium, Pollicotrombium, Paratrombium, and Trombidium) and clade B (Dinothrombium, Clinotrombium, and Allothrombium). However, the within-clade generic relationships were resolved by data from larvae only in clade A and by data from adults only in clade B. Analysis of the combined data produced a single most parsimonious tree, with both clade A (Podothrombium (Pollicotrombium (Paratrombium, Trombidium))) and clade B (Dinothrombium (Clinotrombium, Allothrombium)) completely resolved. Thus, data on larvae and postlarvae are not only congruent but also complementary in revealing the phylogenetic relationships of these mites. The results support the principle of total evidence and the use of all available data for a single parsimony analysis.


Zootaxa ◽  
2020 ◽  
Vol 4886 (1) ◽  
pp. 1-77
Author(s):  
RICARDO ANTONIO GONÇALVES ◽  
ANTONIO DOMINGOS BRESCOVIT

A taxonomic revision and phylogenetic analysis of the spider genus Epicratinus Jocqué & Baert, 2005 is presented. The phylogenetic analysis is based on a data set including 16 Epicratinus species plus 9 outgroups representing by five related zodariid gen­era and one of them considered most basal as the root. These taxa were scored for 49 morphological characters. Parsimony was used as the op­timality criterion and a sensitivity analysis was performed using different character weighting concavities. Five unambiguous synapomorphies support the monophyly of Epicratinus. Some internal clades within the genus are well-supported and their relationships are discussed. Epicratinus includes 16 species, all with males and females. A species identification key and distribution maps are provided for all. New morphological data are also pre­sented for five previously described species. All 16 species occur only in the New World. The following species are transferred to Epicratinus: E. perfidus (Jocqué & Baert), comb. nov. from Tenedos; Epicratinus perfidus Jocqué & Baert comb. nov. and newly synonymized with E. santacruz Grismado & Izquierdo and this last species is treated as the junior synonym. Epicratinus petropolitanus (Mello-Leitão) has the male described for the first time. The following 11 species are newly described as new: E. zangief sp. nov.; E. pegasus sp. nov.; E. pikachu sp. nov.; E. stitch sp. nov.; E. ehonda sp. nov.; E. anakin sp. nov.; E. vader sp. nov.; E. omegarugal sp. nov.; E. zelda sp. nov.; E. dookan sp. nov. and E. mauru sp. nov., all from Brazil. 


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12160
Author(s):  
Jessie Atterholt ◽  
Holly N. Woodward

Bone histology of crown-group birds is a research topic of great interest, permitting insight into the evolution of remarkably high growth rates in this clade and variation across the altricial-precocial spectrum. In this study, we describe microanatomical characteristics of the humerus and femur in partial growth series from 14 crown group birds representing ten major clades (Struthioniformes, Galliformes, Apodiformes, Columbiformes, Charadriiformes, Accipitriformes, Strigiformes, Psittaciformes, Falconiformes, and Passeriformes). Our goals were to: (1) describe the microanatomy of each individual; (2) make inter-and intra-taxonomic comparisons; (3) assess patterns that correspond with developmental mode; and (4) to further parse out phylogenetic, developmental, and functional constraints on avian osteological development. Across taxa, the femoral and humeral tissue of neonates can be broadly characterized as highly-vascularized, disorganized woven bone with great variation in cortical thickness (inter-and intrataxonomically, within an individual specimen, and within a single section). The tissue of precocial chicks is relatively more mature at hatching than in altricial, but other categories along the developmental spectrum were less easy to distinguish, thus we were unable to identify a definitive histological proxy for developmental mode. We did not find evidence to support hypotheses that precocial chicks exclusively have thicker cortices and more mature bone in the femur than the humerus at time of hatching; instead, this is a characteristic of nearly all taxa (regardless of developmental mode), suggesting deep evolutionary origins and the effects of developmental channeling. Bone tissue in adults exhibited unexpected variation, corresponding to differences in body size. Large-bodied birds have cortices of fibrolamellar bone, but organization of tissue increases and vascularity decreases with diminishing body size. The outer circumferential layer (OCL) also appears at earlier growth stages in small-bodied taxa. Thus, while the OCL is indicative of a cessation of appositional growth it is not always indicative of cortical maturity (that is, maximum organization of bony tissue for a given taxon). Small size is achieved by truncating the period of fast growth; manipulation of the timing of offset of bone growth is therefore an important factor in changing growth trajectories to alter adult body size.


2019 ◽  
Vol 118 (8) ◽  
pp. 236-240
Author(s):  
Dr.R. Murugesan ◽  
M. Leelavathi ◽  
Dr. K. Ravindran

towards jumping from the category of developing economy to developed economy there is one big factor that stops and poses a hindrance in its path of advancement and that obstacle is termed as Poverty. The Indian economic policy focuses on a high growth rate along with a equal participation of the poor so that they avail the opportunities available in the market economy. And in order to ensure the participation of the poor it has become important for the country to create a platform where the poor can easily access the various financial products. Microfinance is one such strategy for inclusive growth. Microfinance can change the life of the poor though not completely but a reasonable change can be ensured. In different phases of life women play a crucial role despite the discrimination that is faced by them. But equality can be endowed to women by enhancing the entrepreneurial skills in them. This is possible through Self Help Groups (SHGs). In India women produce around 30% of the total food consumed but she gets only 10% of the property or wealth of the country. Development of women is inevitable for the development and growth of any economy. SHGs happen to be a positive step in this direction. Along with these mediums there should be a cheap and easy source of credit for them and Microfinance fulfills the requirement. This study aims to find the role of this strong medium of Microfinance in the advancement of SHGs in India


2013 ◽  
Vol 740-742 ◽  
pp. 323-326
Author(s):  
Kassem Alassaad ◽  
François Cauwet ◽  
Davy Carole ◽  
Véronique Soulière ◽  
Gabriel Ferro

Abstract. In this paper, conditions for obtaining high growth rate during epitaxial growth of SiC by vapor-liquid-solid mechanism are investigated. The alloys studied were Ge-Si, Al-Si and Al-Ge-Si with various compositions. Temperature was varied between 1100 and 1300°C and the carbon precursor was either propane or methane. The variation of layers thickness was studied at low and high precursor partial pressure. It was found that growth rates obtained with both methane and propane are rather similar at low precursor partial pressures. However, when using Ge based melts, the use of high propane flux leads to the formation of a SiC crust on top of the liquid, which limits the growth by VLS. But when methane is used, even at extremely high flux (up to 100 sccm), no crust could be detected on top of the liquid while the deposit thickness was still rather small (between 1.12 μm and 1.30 μm). When using Al-Si alloys, no crust was also observed under 100 sccm methane but the thickness was as high as 11.5 µm after 30 min growth. It is proposed that the upper limitation of VLS growth rate depends mainly on C solubility of the liquid phase.


2013 ◽  
Vol 687 ◽  
pp. 255-261 ◽  
Author(s):  
Sandra Cunha ◽  
José Barroso Aguiar ◽  
Victor Ferreira ◽  
António Tadeu

Increasingly in a society with a high growth rate and standards of comfort, the need to minimize the currently high energy consumption by taking advantage of renewable energy sources arises. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing for an increase in the level of thermal comfort and reduction of the use of heating, ventilation and air conditioning (HVAC) equipment, using only the energy supplied by the sun. However, the incorporation of PCM in mortars modifies some of its characteristics. Therefore, the main objective of this study was the characterization of mortars doped with two different phase change materials. Specific properties of different PCM, such as particle size, shape and enthalpy were studied, as well as the properties of the fresh and hardened state of these mortars. Nine different compositions were developed which were initially doped with microcapsules of PCM A and subsequently doped with microcapsules of PCM B. It was possible to observe that the incorporation of phase change materials in mortars causes differences in properties such as compressive strength, flexural strength and shrinkage. After the study of the behaviour of these mortars with the incorporation of two different phase change materials, it was possible to select the composition with a better compromise between its aesthetic appearance, physical and mechanical characteristics.


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