Perspective: Parsimony, explanatory power, and dynamic homology testing

Much ado about nothing: inapplicable data as insertion-deletion events

The treatment of inapplicable characters has proved especially vexing to systematists. Investigators have wrestled with alternative coding scenarios to capture both the presence and absence of a feature, and its variation when present, in a reasonable manner. Three basic issues have presented themselves: (i) impossible states at internal nodes; (ii) action at a distance among disparate parts of the tree; and (iii) "secondary" (i.e. aspect variation) characters overwhelming "primary" (i.e. character presence/absence) patterns in grouping taxa. Multiple methods have been proposed to deal with these issues in the context of standard character coding with varying levels of complexity. Here, I show that these issues can be dealt with in a direct fashion by treating presence/absence not as a character, but as insertion/deletion of a character with all its potential variation. This approach removes these three problems in simple, straightforward manner.

A new golden species of Diasporus (Anura: Eleutherodactylidae) from southwestern Colombia, with evaluation of the phylogenetic significance of morphological characters in Diasporus

A new species of Diasporus is described from the lowlands of southwestern Colombia. The new species exhibits a yellowish coloration in life, a character that it shares with other three species in the genus-Diasporus citrinobapheus, D. gularis, and D. tigrillo. The new species differs from all other congeners in having two chrome orange spots (=glandlike protrusions) on sacral region, smooth ventral skin, basal webbing between the toes, and distal papillae at tips of disc covers on fingers II-IV and toes II-IV. Further, the new species differs from all congeners by an uncorrected p-distance of > 5.56% of the 16S rRNA gene fragment examined. In addition to the new species described herein, we demonstrated that the possession of a yellowish coloration in life optimizes unambiguously as a synapomorphy of a clade within Diasporus, which may be recognized as the Diasporus diastema species group. We also discussed the phylogenetic significance of two morphological characters previously considered of systematic value in Diasporus, the occurrence of oval palmar tubercles (undivided) and longitudinal folds (of the vocal sacs) on the throat. On this basis, we demonstrated that these characters appear to be symplesiomorphies rather than synapomorphies of Diasporus. Regarding pointed disc covers (ungual flap) present in some species of Diasporus, we show that this character conflates various characters, involving variation in pad shape, dorsal outline of the disc (ungual flap), and dependence between discs of different digits. Finally, considering that phenotypic data are a valuable source of evidence in testing phylogenetic hypotheses of terraranan frogs, we encourage future research to incorporate phenotypic evidence into phylogenetic studies involved in the genus Diasporus.

Fundamental evolution of all Orthocoronavirinae including three deadly lineages descendent from Chiroptera-hosted coronaviruses: SARS-CoV, MERS-CoV and SARS-CoV-2

The severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in humans in 2002. Despite reports showing Chiroptera as the original animal reservoir of SARS-CoV, many argue that Carnivora-hosted viruses are the most likely origin. The emergence of the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 also involves Chiroptera-hosted lineages. However, factors such as the lack of comprehensive phylogenies hamper our understanding of host shifts once MERS-CoV emerged in humans and Artiodactyla. Since 2019, the origin of SARS-CoV-2, causative agent of coronavirus disease 2019 (COVID-19), added to this episodic history of zoonotic transmission events. Here we introduce a phylogenetic analysis of 2006 unique and complete genomes of different lineages of Orthocoronavirinae. We used gene annotations to align orthologous sequences for total evidence analysis under the parsimony optimality criterion. Deltacoronavirus and Gammacoronavirus were set as outgroups to understand spillovers of Alphacoronavirus and Betacoronavirus among ten orders of animals. We corroborated that Chiroptera-hosted viruses are the sister group of SARS-CoV, SARS-CoV-2 and MERS-related viruses. Other zoonotic events were qualified and quantified to provide a comprehensive picture of the risk of coronavirus emergence among humans. Finally, we used a 250 SARS-CoV-2 genomes dataset to elucidate the phylogenetic relationship between SARS-CoV-2 and Chiroptera-hosted coronaviruses.

Phylogenetic relationships of the genus Mischonyx Bertkau, 1880, with taxonomic changes and three new species description (Opiliones: Gonyleptidae)

The type species of Mischonyx Bertkau 1880, Mischonyx squalidus, was described based on a juvenile. The holotype is lost. Based on a revision of publications, the genus includes 12 species, all in Brazil. The objectives of this research are: to propose a phylogenetic hypothesis for Mischonyx based on Total Evidence (TE); propose taxonomic changes based on the phylogeny; and analyze the phylogenetic hypothesis biogeographically. Using the exemplar approach to taxon selection, we studied 54 specimens, 15 outgroups and 39 ingroup taxa using seven molecular markers (28S, 12S and 16S ribosomal genes, citochrome oxidase subunit I gene, carbamoyl-phosphate synthetase gene, internal transcribed spacer subunit 2 and histone H3 gene), totaling 3,742 bp, and 128 morphological characters. We analyzed the dataset under three optimality criteria: Maximum likelihood (ML), Maximum parsimony (MP) and Bayesian. We discuss the transformation of character states throughout the phylogeny, the different phylogenetic hypotheses using different datasets and the congruence of evidence between the clades obtained by the phylogenetic analysis and the biogeographical hypothesis for the Atlantic Forest areas of endemism. We estimate that Mischonyx clade diverged 50.53 Mya, and inside the genus there are two major clades. One of them cointains species from Paraná, Santa Catarina, South of São Paulo and Serra do Mar Areas of Endemism and the other has species from Espinhaço, Bocaina, South coast of Rio de Janeiro and Serra dos Órgãos Areas of Endemism. The first split inside these two clades occurred at 48.94 and 44.80 Mya, respectively. We describe three new species from Brazil: Mischonyx minimus sp. nov. (type locality: Petrópolis, Rio de Janeiro), Mischonyx intervalensis sp. nov. (type locality: Ribeirão Grande, São Paulo) and Mischonyx tinguaensis sp. nov (type locality: Nova Iguaçu, Rio de Janeiro). The genus Urodiabunus Mello-Leitão, 1935 is considered a junior synonym of Mischonyx. Weyhia spinifrons Mello-Leitão, 1923; Weyhia clavifemur Mello-Leitão, 1927 and Geraeocormobius reitzi Vasconcelos, 2005 were transferred to Mischonyx. Mischonyx cuspidatus (Roewer, 1913) is a junior synonym of M. squalidus Bertkau, 1880. In the results of the phylogenetic analyses, Gonyleptes antiquus Mello-Leitão, 1934 (former Mischonyx antiquus) does not belong in Mischonyx and its original combination is re-established. As it is now defined, Mischonyx comprises 17 species, with seven new combinations.

The phylogeny of the Casque-headed Treefrogs (Hylidae: Hylinae: Lophyohylini)

The South American and West Indian Casque-headed Treefrogs (Hylidae: Hylinae: Lophyohylini) include 85 species. These are notably diverse in morphology (e.g. disparate levels of cranial hyperossification) and life history (e.g. different reproductive modes, chemical defences), have a wide distribution, and occupy habitats from the tropical rainforests to semiarid scrubland. In this paper, we present a phylogenetic analysis of this hylid tribe based on sequence fragments of up to five mitochondrial (12S, 16S, ND1, COI, Cytb) and six nuclear genes (POMC, RAG-1, RHOD, SIAH, TNS3, TYR). We included most of its species (> 96%), in addition to a number of new species. Our results indicate: (i) the paraphyly of Trachycephalus with respect to Aparasphenodon venezolanus; (ii) the nonmonophyly of Aparasphenodon, with Argenteohyla siemersi, Corythomantis galeata and Nyctimantis rugiceps nested within it, and Ap. venezolanus nested within Trachycephalus; (iii) the polyphyly of Corythomantis; (iv) the nonmonophyly of the recognized species groups of Phyllodytes; and (v) a pervasive low support for the deep relationships among the major clades of Lophyohylini, including C. greeningi and the monotypic genera Itapotihyla and Phytotriades. To remedy the nonmonophyly of Aparasphenodon, Corythomantis, and Trachycephalus, we redefined Nyctimantis to include Aparasphenodon (with the exception of Ap. venezolanus, which we transferred to Trachycephalus), Argenteohyla, and C. galeata. Additionally, our results indicate the need for taxonomic work in the following clades: (i) Trachycephalus dibernardoi and Tr. imitatrix; (ii) Tr. atlas, Tr. mambaiensis and Tr. nigromaculatus; and (iii) Phyllodytes. On the basis of our phylogenetic results, we analyzed the evolution of skull hyperossification and reproductive biology, with emphasis on the multiple independent origins of phytotelm breeding, in the context of Anura. We also analyzed the inter-related aspects of chemical defences, venom delivery, phragmotic behaviour, co-ossification, and prevention of evaporative water loss.

The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae)

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups of Dendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized in Dendropsophus, we performed a total evidence phylogenetic analysis. The molecular dataset included sequences of three mitochondrial and five nuclear genes from 210 terminals, including 12 outgroup species, the two species of Xenohyla, and 93 of the 108 recognized species of Dendropsophus. The phenomic dataset includes 46 terminals, one per species (34 Dendropsophus, one Xenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly of Dendropsophus and Xenohyla. Some species groups of Dendropsophus are paraphyletic (the D. microcephalus, D. minimus, and D. parviceps groups, and the D. rubicundulus clade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus, D. microcephalus, and D. parviceps groups) we recognize some nominal clades to highlight specific morphology or relationships and facilitate species taxonomy. We further discuss the evolution of oviposition site selection, where our results show multiple instances of independent evolution of terrestrial egg clutches during the evolutionary history of Dendropsophus.

A new genus of fossil frog (Anura) from lower Cretaceous deposits in South America

The frog clade Neobatrachia or "advanced frogs" represents more than 95% of the diversity within Anura. The neobatrachian fossil record is incomplete due to the small size and fragile nature of their bones but provides some clues on the time and rate of the current diversification of modern-day amphibians. The Crato Formation (Aptian) of northeastern Brazil is known for the presence of, at least, five species of neobatrachian fossils. Herein, we describe a well-preserved fossil that represents a new neobatrachian taxon from the Crato Formation (Cretaceous) in the Araripe Basin, northeastern Brazil, and perform phylogenetic analysis to assess its higher-level relationships. The new specimen is an almost complete and articulated skeleton with soft tissue preservation. Phylogenetic analysis recovered the specimen nested in the clade Hyloidea and our results highlight the remarkable value of the Crato Formation as a Laggerstätte.

Phylogenetic relationships of the Boana pulchella Group (Anura: Hylidae)

In this paper we present a phylogenetic analysis of the treefrogs of the Boana pulchella Group with the goals of (1) providing a rigorous test of its monophyly; (2) providing a test of relationships supported in previous studies; and (3) exploring the relationships of the several species not included in previous analyses. The analyses included>300 specimens of 37 of the 38 species currently included in the group, plus 36 outgroups, exemplars of the diversity of Boana and the other genera of the hylid tribe Cophomantini. The dataset included eight mitochondrial genes (12S, 16S, CytB, COI, ND1, tRNA^Ile, tRNA^Leu, and tRNA^Val) and five nuclear genes (RHO, TYR, RAG-1, CXCR4, SIAH1). The phylogenetic analyses recover the monophyly of the B. pulchella Group with lower support than previous studies, as a result of the inclusion of the B. claresignata Group, which is recovered as its sister taxon. Within the B. pulchella Group, the inclusion of almost all species of the group had little impact on previous notions of its phylogeny, except for the rejection of the hypothesized B. polytaenia Clade (B. goiana and B. phaeopleura are nested in the clade here called the B. prasina Clade), which is redefined. Phylogenetic support is strong for five major clades, which collectively include all but three of the species sampled: the B. balzani Clade (B. aguilari, B. balzani, B. gladiator, B. melanopleura, B. palaestes), the redefined B. polytaenia Clade (B. botumirim, B. buriti, B. cipoensis, B. jaguariaivensis, B. leptolineata, B. polytaenia, B. stenocephala, and two undescribed species), the B. prasina Clade (B. bischoffi, B. caingua, B. cordobae, B. goiana, B. guentheri, B. marginata, B. phaeopleura, B. prasina, B. pulchella, and one undescribed species), the B. riojana Clade (B. callipleura, B. marianitae, B. riojana), and the B. semiguttata Clade (B. caipora, B. curupi, B. joaquini, B. poaju, B. semiguttata, B. stellae, and two undescribed species). The monophyly of the B. prasina + B. riojana Clades, and that of the B. polytaenia + B. semiguttata Clades are well-supported. The relationships among these two clades, the B. balzani Clade, B. ericae + B. freicanecae, and B. cambui (representing the deepest phylogenetic splits within the B. pulchella Group) are recovered with weak support. We discuss the phenotypic evidence supporting the monophyly of the B. pulchella Group, and the taxonomy of several species, identifying three new synonyms of Boana polytaenia, one new synonym of Boana goiana, and one new synonym of B. riojana.

FLAVi: An Enhanced Annotator for Viral Genomes of Flaviviridae

Responding to the ongoing and severe public health threat of viruses of the family Flaviviridae, including dengue, hepatitis C, West Nile, yellow fever, and Zika, demands a greater understanding of how these viruses emerge and spread. Updated phylogenies are central to this understanding. Most cladograms of Flaviviridae focus on specific lineages and ignore outgroups, hampering the efficacy of the analysis to test ingroup monophyly and relationships. This is due to the lack of annotated Flaviviridae genomes, which has gene content variation among genera. This variation makes analysis without partitioning difficult. Therefore, we developed an annotation pipeline for the genera of Flaviviridae (Flavirirus, Hepacivirus, Pegivirus, and Pestivirus, named "Fast Loci Annotation of Viruses" (FLAVi; http://flavi-web.com/), that combines ab initio and homology-based strategies. FLAVi recovered 100% of the genes in Flavivirus and Hepacivirus genomes. In Pegivirus and Pestivirus, annotation efficiency was 100% except for one partition each. There were no false positives. The combined phylogenetic analysis of multiple genes made possible by annotation has clear impacts over the tree topology compared to phylogenies that we inferred without outgroups or data partitioning. The final tree is largely congruent with previous hypotheses and adds evidence supporting the close phylogenetic relationship between dengue and Zika.

High-throughput DNA sequencing of museum specimens sheds light on the long-missing species of the Bokermannohyla claresignata group (Anura: Hylidae: Cophomantini)

The two species of the Bokermannohyla claresignata species group (Anura: Hylidae) have not been collected for the last four decades. It is the only species group of the hyline tribe Cophomantini that has not yet been analysed genetically. Its phylogenetic position is thus uncertain, and it has a combination of adult and larval character states that make this group a crucial missing piece that hinders our understanding of Cophomantini phylogenetics and character evolution. We obtained DNA sequences from a museum larval specimen of Bok. claresignata, using specialized extraction methods and high-throughput DNA sequencing, and combined the molecular phylogenetic results with available phenotypic information to provide new insights into the taxonomy and phylogenetic relationships of its species group. Our phylogenetic results place Bok. claresignata as sister to the Boana pulchella group, supporting its inclusion in Boana, together with Bokermannohyla clepsydra. In light of this new finding, we recognize a newly defined Boana claresignata group to accommodate these species, thus resolving both the polyphyly of Bokermannohyla and the paraphyly of Boana. Considering the phylogenetic relationships of the Boana claresignata group, we also discuss the evolution of suctorial tadpoles and mature oocyte/egg pigmentation in Cophomantini.

Vastly underestimated species richness of Amazonian salamanders (Plethodontidae: Bolitoglossa) and implications about plethodontid diversification

We present data showing that the number of salamander species in Amazonia is vastly underestimated. We used DNA sequences of up to five genes (3 mitochondrial and 2 nuclear) of 366 specimens, 189 corresponding to 89 non-Amazonian nominal species and 177 Amazonian specimens, including types or topotypes, of eight of the nine recognized species in the region. By including representatives of all known species of Amazonian Bolitoglossa, except for one, and 73% of the currently 132 recognized species of the genus, our dataset represents the broadest sample of Bolitoglossa species, specimens, and geographic localities studied to date. We performed phylogenetic analyses using parsimony with tree-alignment and maximum likelihood (ML) with similarity alignment, with indels as binary characters. Our optimal topologies were used to delimit lineages that we assigned to nominal species and candidate new species following criteria that maximize the consilience of the current species taxonomy, monophyly, gaps in branch lengths, genetic distances, and geographic distribution. We contrasted the results of our species-delimitation protocol with those of Automated Barcode Gap Discovery (ABGD) and multi-rate Poisson Tree Processes (mPTP). Finally, we inferred the historical biogeography of South American salamanders by dating the trees and using dispersal-vicariance analysis (DIVA). Our results revealed a clade including almost all Amazonian salamanders, with a topology incompatible with just the currently recognized nine species. Following our species-delimitation criteria, we identified 44 putative species in Amazonia. Both ABGD and mPTP inferred more species than currently recognized, but their numbers (23-49) and limits vary. Our biogeographic analysis suggested a stepping-stone colonization of the Amazonian lowlands from Central America through the Chocó and the Andes, with several late dispersals from Amazonia back into the Andes. These biogeographic events are temporally concordant with an early land bridge between Central and South America (~10-15 MYA) and major landscape changes in Amazonia during the late Miocene and Pliocene, such as the drainage of the Pebas system, the establishment of the Amazon River, and the major orogeny of the northern Andes.

Exploring the impact of morphology, multiple sequence alignment and choice of optimality criteria in phylogenetic inference: a case study with the Neotropical orb-weaving spider genus Wagneriana (Araneae: Araneidae)

We present a total evidence phylogenetic analysis of the Neotropical orb-weaving spider genus Wagneriana and discuss the phylogenetic impacts of methodological choices. We analysed 167 phenotypic characters and nine loci scored for 115 Wagneriana and outgroups, including 46 newly sequenced species. We compared total evidence analyses and molecular-only analyses to evaluate the impact of phenotypic evidence, and we performed analyses using the programs POY, TNT, RAxML, GARLI, IQ-TREE and MrBayes to evaluate the effects of multiple sequence alignment and optimality criteria. In all analyses, Wagneriana carimagua and Wagneriana uropygialis were nested in the genera Parawixia and Alpaida, respectively, and the remaining species of Wagneriana fell into three main clades, none of which formed a pair of sister taxa. However, sister-group relationships among the main clades and their internal relationships were strongly influenced by methodological choices. Alignment methods had comparable topological effects to those of optimality criteria in terms of ‘subtree pruning and regrafting’ moves. The inclusion of phenotypic evidence, 2.80–3.05% of the total evidence matrices, increased support irrespective of the optimality criterion used. The monophyly of some groups was recovered only after the addition of morphological characters. A new araneid genus, Popperaneus gen. nov., is erected, and Paraverrucosa is resurrected. Four new synonymies and seven new combinations are proposed.

A total evidence analysis of the phylogeny of hatchet-faced treefrogs (Anura: Hylidae: Sphaenorhynchus)

The Neotropical hylid genus Sphaenorhynchus includes 15 species of small, greenish treefrogs widespread in the Amazon and Orinoco basins, and in the Atlantic Forest of Brazil. Although some studies have addressed the phylogenetic relationships of the genus with other hylids using a few exemplar species, its internal relationships remain poorly understood. In order to test its monophyly and the relationships among its species, we performed a total evidence phylogenetic analysis of sequences of three mitochondrial and three nuclear genes, and 193 phenotypic characters from all species of Sphaenorhynchus. Our results support the monophyly of Sphaenorhynchus with molecular and phenotypic evidence, with S. pauloalvini as the earliest diverging taxon, followed by S. carneus, as the sister taxon of all remaining species of the genus. We recognize three species groups in Sphaenorhynchus (the S. lacteus, S. planicola and S. platycephalus groups), to facilitate its taxonomic study; only three species (S. carneus, S. pauloalvini and S. prasinus) remain unassigned to any group. Sequence data were not available for only two species (S. bromelicola and S. palustris) for which we scored phenotypic data; wildcard behaviour was detected only in S. bromelicola nested inside the S. platycephalus group. On the basis of the resulting phylogenetic hypothesis, we discuss the evolution of oviposition site and a number of phenotypic characters that could be associated with heterochronic events in the evolutionary history of this group.

Parsimony analysis of unaligned sequence data: some clarifications

De Laet (2015) claimed that minimization of ad hoc hypotheses of homoplasy does not lead to a preference for trivial optimizations when analysing unaligned sequence data, as claimed by Wheeler (2012; see also Kluge and Grant, 2006). In addition, De Laet asserted that Kluge and Grant's (2006) parsimony rationale is internally inconsistent in terms of Baker's (2003) theoretical framework. We argue that De Laet used extraneous presuppositions to critique Wheeler's position and, as such, his criticism should be considered cautiously in terms of its scope. Finally, we demonstrate that considering Kluge and Grant's parsimony rationale as inconsistent rests on De Laet's misunderstanding of the ideographic character concept and the consequences of relating it to Baker's rationale.

Phylogeny of Riama (Squamata: Gymnophthalmidae), impact of phenotypic evidence on molecular datasets, and the origin of the Sierra Nevada de Santa Marta endemic fauna

Riama is the most speciose genus of the Neotropical lizard family Gymnophthalmidae. Its more than 30 montane species occur throughout the northern Andes, the Cordillera de la Costa (CC) in Venezuela, and Trinidad. We present the most comprehensive phylogenetic analysis of Riama to date based on a total evidence (TE) approach and direct optimization of molecular and morphological evidence. Analyses use DNA sequences from four loci and 35 phenotypic characters. The dataset consists of 55 ingroup terminals representing 25 of the 30 currently recognized species of Riama plus five undescribed taxa, including an endemic species from the Sierra Nevada de Santa Marta (SNSM) in Colombia, and 66 outgroup terminals of 47 species. Analysis results in a well-supported hypothesis in which Riama is polyphyletic, with its species falling into three clades. The Tepuian Anadia mcdiarmidi nests within one clade of Riama, and the recently resurrected Pantodactylus nests within Cercosaura. Accordingly, we propose a monophyletic taxonomy that reflects historical relationships. Analysis of character evolution indicates that the presence/absence of prefrontals-a cornerstone of the early genus-level taxonomy of cercosaurines-is optimally explained as having been plesiomorphically present in the most recent common ancestor of Cercosaurinae and lost in that of the immediately less inclusive clade. Multiple independent reversals to present and subsequent returns to absent occur within this clade. To evaluate the impact of phenotypic evidence on our results, we compare our TE results with results obtained from analyses using only molecular data. Although phenotypic evidence comprises only 1.2% of the TE matrix, its inclusion alters both the topology and support values of the clades that do not differ. Finally, current phylogenetic evidence reveals a SNSM-CC-Trinidad-tepuis biogeographical link. We hypothesize that an ancient connection facilitated the exchange of species between the SNSM and the CC.

Piecemeal Buildup of the Genetic Code, Ribosomes, and Genomes from Primordial tRNA Building Blocks

The origin of biomolecular machinery likely centered around an ancient and central molecule capable of interacting with emergent macromolecular complexity. tRNA is the oldest and most central nucleic acid molecule of the cell. Its co-evolutionary interactions with aminoacyl-tRNA synthetase protein enzymes define the specificities of the genetic code and those with the ribosome their accurate biosynthetic interpretation. Phylogenetic approaches that focus on molecular structure allow reconstruction of evolutionary timelines that describe the history of RNA and protein structural domains. Here we review phylogenomic analyses that reconstruct the early history of the synthetase enzymes and the ribosome, their interactions with RNA, and the inception of amino acid charging and codon specificities in tRNA that are responsible for the genetic code. We also trace the age of domains and tRNA onto ancient tRNA homologies that were recently identified in rRNA. Our findings reveal a timeline of recruitment of tRNA building blocks for the formation of a functional ribosome, which holds both the biocatalytic functions of protein biosynthesis and the ability to store genetic memory in primordial RNA genomic templates.

Ribosomal accretion, apriorism and the phylogenetic method: a response to Petrov and Williams

Historical (ideographic) and non-historical (nomothetic) studies of ribosomal accretion appear to arrive at diametrically opposite conclusions. Phylogenetic analysis of thousands of RNA molecules and protein structures in hundreds of genomes supports the structural origin of the ribosome in RNA decoding and ribosomal mechanics. Predictions from extant features in a handful of rRNA structural models of the large ribosomal subunit support its origin in protein biosynthesis. In recent correspondence, one of us reported that correcting dismissals of conflicting data and avoiding unwarranted assumptions of the nomothetic method reconciled conclusions. In response, Petrov and Williams dismissed our arguments claiming we did not understand their algorithmic model of ribosomal apical growth. Instead, they controverted the historical approach. Here we show that their objections to the phylogenetic method are unjustified, that their algorithm subjectively guarantees back-in-time molecular deconstructions toward the protein biosynthetic core, and that processes of ribosomal growth are much more complex. We prompt abandoning apriorism, decreasing ad hoc hypotheses and integrating historical and non-historical scientific methods.

REP provides meaningful measurement of support across datasets

The relative optimality of the best and next-best hypotheses indicates the strength of support for the optimal hypothesis and may be calculated as either the difference or ratio of their optimality scores. The Goodman-Bremer support measure (GB) calculates the support for a given clade in the most parsimonious tree as the difference between the length of the optimal tree and the optimal tree that lacks that clade. The ratio of explanatory power (REP) support measure calculates support as the ratio of optimality scores, which simplifies to the ratio of observed GB and the maximum possible GB, GB/GB(max). In this paper we show that REP support provides a logical basis for comparison of support across datasets and that recent claims to the contrary are incorrect.