character weighting
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Author(s):  
Jozef Klembara ◽  
Marcello Ruta ◽  
Miroslav Hain ◽  
David S. Berman

The braincase anatomy of the Pennsylvanian diadectomorph Limnoscelis dynatis is described in detail, based upon high-resolution X-ray microcomputed tomography. Both supraoccipitals and most of the prootics and opisthotics are preserved. The known portions of the left prootic, opisthotic, and supraoccipital enclose complete sections of the endosseous labyrinth, including the anterior, posterior, and lateral semicircular canals, the vestibule, the cochlear recess, and the canal for the endolymphatic duct. The fossa subarcuata is visible anteromedial to the anterior semicircular canal. The presumed endolymphatic fossae occur in the dorsal wall of the posteromedial portion of the supraoccipital. Both the fossa subarcuata and the fossa endolymphatica lie in the cerebellar portion of the cranial cavity. In order to investigate the phylogenetic position of L. dynatis we used a recently published data matrix, including characters of the braincase, and subjected it to maximum parsimony analyses under a variety of character weighting schemes and to a Bayesian analysis. Limnoscelis dynatis emerges as sister taxon to L. paludis, and both species form the sister group to remaining diadectomorphs. Synapsids and diadectomorphs are resolved as sister clades in ∼90% of all the most parsimonious trees from the unweighted analysis, in the single trees from both the reweighted and the implied weights analyses, as well in the Bayesian tree.


2021 ◽  
pp. 142-185
Author(s):  
Andrew V. Z. Brower ◽  
Randall T. Schuh

This chapter evaluates “quantitative cladistics” in detail, including the issues of fit, parsimony algorithms, and character weighting. Although systematists have long associated characters with taxa, the relationship between character data and “phylogeny” has not always been obvious. The ideas of Willi Hennig clarified this relationship, and the formalization of these concepts in a quantitative method, via the parsimony criterion, allowed for computer implementation of phylogenetic inference and the feasible solution of previously intractable problems. It is this computational capability that took the study of taxonomic relationships from an almost purely qualitative and speculative enterprise to one dominated by the use of computer software and “objective” methodologies. The chapter then discusses the use, advantages, and disadvantages of maximum likelihood and Bayesian techniques as alternative approaches to the application of parsimony.


2021 ◽  
Vol 45 (1) ◽  
pp. 77-89
Author(s):  
O. Petrova ◽  
K. Bulatov ◽  
V.V. Arlazarov ◽  
V.L. Arlazarov

The scope of uses of automated document recognition has extended and as a result, recognition techniques that do not require specialized equipment have become more relevant. Among such techniques, document recognition using mobile devices is of interest. However, it is not always possible to ensure controlled capturing conditions and, consequentially, high quality of input images. Unlike specialized scanners, mobile cameras allow using a video stream as an input, thus obtaining several images of the recognized object, captured with various characteristics. In this case, a problem of combining the information from multiple input frames arises. In this paper, we propose a weighing model for the process of combining the per-frame recognition results, two approaches to the weighted combination of the text recognition results, and two weighing criteria. The effectiveness of the proposed approaches is tested using datasets of identity documents captured with a mobile device camera in different conditions, including perspective distortion of the document image and low lighting conditions. The experimental results show that the weighting combination can improve the text recognition result quality in the video stream, and the per-character weighting method with input image focus estimation as a base criterion allows one to achieve the best results on the datasets analyzed.


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. 


2020 ◽  
Vol 52 (2) ◽  
pp. 197-211
Author(s):  
Christoph Germann ◽  
Vasily V. Grebennikov

We describe Zembrus perseus gen. et sp. nov., a new weevil from Yunnan, China. A single flightless male was sifted from under Rhododendron bush in the alpine zone of the Cangshan Mountain Range. The specimen’s appearance suggests affinities to the molytine subtribe Cotasteromimina, which currently comprises six named species in four genera distributed between Japan, the Andaman Islands, Borneo and the Philippines. To test the species’ phylogenetic affinities, we analysed 73 morphological characters of adult specimens of 23 molytine and one rooting species. Besides Z. perseus, the ingroup includes four named species, each representing a named genus of Cotasteromimina, and two other, likely closely related unnamed species. Phylogenetic analysis using the parsimony criterion and four character-weighting and/or ordering strategies consistently failed to detect a clade of Cotasteromimina, either with or without Z. perseus. The most parsimonious trees are inconsistent, the bootstrap consensus trees are almost entirely unresolved, and previously published DNA data are phylogenetically indecisive. We conclude that either adult morphological characters constitute an inadequate data source to test monophyly of Cotasteromimina or that the subtribe is not monophyletic or both. We illustrate the relevant adult structures of Z. perseus and most of the in- and out-group taxa used in the analysis.


2020 ◽  
Author(s):  
Johannes S Neumann ◽  
Rob Desalle ◽  
Apurva Narechania ◽  
Bernd Schierwater ◽  
Michael Tessler

Abstract There are considerable phylogenetic incongruencies between morphological and phylogenomic data for the deep evolution of animals. This has contributed to a heated debate over the earliest-branching lineage of the animal kingdom: the sister to all other Metazoa (SOM). Here, we use published phylogenomic data sets ($\sim $45,000–400,000 characters in size with $\sim $15–100 taxa) that focus on early metazoan phylogeny to evaluate the impact of incorporating morphological data sets ($\sim $15–275 characters). We additionally use small exemplar data sets to quantify how increased taxon sampling can help stabilize phylogenetic inferences. We apply a plethora of common methods, that is, likelihood models and their “equivalent” under parsimony: character weighting schemes. Our results are at odds with the typical view of phylogenomics, that is, that genomic-scale data sets will swamp out inferences from morphological data. Instead, weighting morphological data 2–10$\times $ in both likelihood and parsimony can in some cases “flip” which phylum is inferred to be the SOM. This typically results in the molecular hypothesis of Ctenophora as the SOM flipping to Porifera (or occasionally Placozoa). However, greater taxon sampling improves phylogenetic stability, with some of the larger molecular data sets ($>$200,000 characters and up to $\sim $100 taxa) showing node stability even with $\geqq100\times $ upweighting of morphological data. Accordingly, our analyses have three strong messages. 1) The assumption that genomic data will automatically “swamp out” morphological data is not always true for the SOM question. Morphological data have a strong influence in our analyses of combined data sets, even when outnumbered thousands of times by molecular data. Morphology therefore should not be counted out a priori. 2) We here quantify for the first time how the stability of the SOM node improves for several genomic data sets when the taxon sampling is increased. 3) The patterns of “flipping points” (i.e., the weighting of morphological data it takes to change the inferred SOM) carry information about the phylogenetic stability of matrices. The weighting space is an innovative way to assess comparability of data sets that could be developed into a new sensitivity analysis tool. [Metazoa; Morphology; Phylogenomics; Weighting.]


Author(s):  
Jonathan P Rio ◽  
Philip D Mannion ◽  
Emanuel Tschopp ◽  
Jeremy E Martin ◽  
Massimo Delfino

AbstractDiplocynodon is a genus of basal alligatoroid comprising nine species, which spanned the late Palaeocene to middle Miocene of Europe. Despite recent revisions of most Diplocynodon species, one of the earliest named and most complete, Diplocynodon hantoniensis, has not been re-described for over 150 years. This species is known from the remains of numerous individuals from the Priabonian (late Eocene) Headon Hill Formation, which crops out at Hordle (Hordwell) Cliff in Hampshire, United Kingdom. Here we re-describe and diagnose Diplocynodon hantoniensis, providing the first detailed description of postcranial anatomy in Diplocynodon, and indeed any basal alligatoroid. Diplocynodon hantoniensis is diagnosed by four autapomorphies, including retention of the ectopterygoid–pterygoid flexure through ontogeny and a unique anterior process of the ectopterygoid adjacent to the posteriormost maxillary alveoli. A critical review of previously referred remains from elsewhere in Europe and the USA restricts Diplocynodon hantoniensis to the late Eocene of the UK. Through comparisons with extant crocodylians, the well-preserved postcranial skeleton enables the interpretation of numerous muscle attachments in the forelimbs and hindlimbs, providing a potentially rich source of character data for future phylogenetic analyses. Based on a comparison of humeral morphology between a large sample of crocodylian species, we outline two new morphological characters in the humerus. We include D. hantoniensis in a phylogenetic analysis, including all putative Diplocynodon species (103 taxa scored for 187 characters). We use four different character-weighting schemes: equal weighting, implied weighting (k value = 8) and extended implied weighting with k-values of 4 and 8. In general, these weighted analyses produce congruent results with the equal-weights analysis, and increase the resolution within Diplocynodon. We recover a monophyletic Diplocynodon in three of the four analyses. However, the fourth analysis, with the strongest downweighting of homoplastic characters and missing data (extended implied weighting with k = 4), recovers the Palaeocene Diplocynodon remensis outside Diplocynodon. Our comprehensive revision of one of the most completely known Diplocynodon species facilitates comparisons in the genus, as well as between other basal alligatoroids, and forms the basis for comparing postcranial anatomy in other fossil crocodylians.


2017 ◽  
Vol 31 (4) ◽  
pp. 442 ◽  
Author(s):  
Miguel Machado ◽  
Renato A. Teixeira ◽  
Arno A. Lise

The present paper presents a cladistic analysis of the spider genus Tobias Simon, 1895. The analyses were based on a matrix with 29 terminal taxa scored for 86 morphological characters, with a dataset tested under two methodologies for character weighting (i.e. equal and implied weighting). Both analyses supported the paraphyletic relationship of Tobias with Epicadus Simon, 1895, with the former considered a junior synonym of the latter (new synonymy). Onocolus, Epicadinus and Epicadus form a clade supported by two synapomorphies, corroborating previous taxonomic assumptions regarding the proximity of these genera. Epicadus has two lineages: the ‘pustulosus clade’, comprising bark-like individuals that camouflage themselves on tree trunks and branches, and the ‘heterogaster clade’, which consists of a group of spiders that present a wide range of polychromatism and use flowers as hunting sites. Synonymies are presented and a new combination for all species previously assigned as part of Tobias is proposed. Epicadus now comprises nine species.


2015 ◽  
Vol 3 (1) ◽  
pp. 84-117
Author(s):  
Christina Michelle Skelton

Phylogenetic systematics is an increasingly popular tool in historical linguistics for reconstructing the evolutionary histories of groups of languages. One problem in applying phylogenetic methods to languages is that phylogenetic methods assume evolution takes place strictly by descent with modification, whereas borrowing between languages is common. This paper tests two different methods for addressing borrowing in phylogenetic analysis of language on a dataset representing the dialects of ancient Greek: character weighting and preliminary cluster analysis. Both methods show promise; they correctly recovered the subgrouping of the Greek dialects and were able to improve the resolution of the tree compared to the preliminary analysis. However, they recovered conflicting subgroupings of the West Greek dialects. This result is most likely due to a circular dialect continuum within West Greek. Using phylogenetic methods in situations which match their assumptions is crucial; for the West Greek dialects, phylogenetic network methods would be more appropriate.


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