Unrelated Clades Research Articles

Phylogenomic and molecular marker based studies to clarify the evolutionary relationships amongst Anoxybacillus species and demarcation of the family Anoxybacillaceae and some of its constituent genera.

The family Anoxybacillaceae was recently proposed encompassing the genera Anoxybacillus, Geobacillus, Parageobacillus, Saccharococcus and Thermolongibacillus. Of these genera, Anoxybacillus contains >50% of the Anoxybacillaceae species. However, Anoxybacillus species form multiple unrelated clades in phylogenetic trees and their evolutionary relationships are unclear. To clarify the evolutionary relationships of Anoxybacillus and other Anoxybacillaceae species, detailed phylogenomic and comparative analyses were conducted on 38 Anoxybacillaceae species with available genomes. In a phylogenomic tree based on 1148 core proteins, all Anoxybacillus, Geobacillus, Parageobacillus, Saccharococcus and Thermolongibacillus species, excepting Anoxybacillus sediminis, formed a strongly supported clade representing the family Anoxybacillaceae. Five conserved signature indels (CSIs) reported here are also uniquely found in these species, providing robust means for the demarcation of family Anoxybacillaceae in molecular terms. In our phylogenomic tree and in the Genomic Taxonomy Database, Anoxybacillus species formed four distinct clades designated as Anoxybacillus sensu stricto (containing the type species A. pushchinoensis), Anoxybacillus_A, Anoxybacillus_B and Anoxybacillus_C. Our analyses have identified 17 novel CSIs which offer means to reliably distinguish species from these clades based upon multiple uniquely shared molecular characteristics. Additionally, we have identified three and seven CSIs specific for the genera Geobacillus and Brevibacillus, respectively. All seven Brevibacillus-specific CSIs are also shared by Anoxybacillus sediminis, which branches reliably with this genus. Based on the strong phylogenetic and molecular evidence presented here, we are proposing that the genus Anoxybacillus should be restricted to only the species from Anoxybacillus sensu stricto clade, whereas the species from Anoxybacillus_A, Anoxybacillus_B, and Anoxybacillus_C clades should be transferred into three novel genera Anoxybacteroides gen. nov., Paranoxybacillus gen. nov. and Thermaerobacillus gen. nov., respectively. Additionally, we are also proposing the transfer of Anoxybacillus sediminis to the genus Brevibacillus. The proposed changes, which reliably depict the evolutionary relationships among Anoxybacillaceae species, should be helpful in the studies of these organisms.

Unveiling the molecular epidemiology of canine distemper virus in Namibia: An expected pathogen showing an unexpected origin

ObjectiveCanine distemper virus (CDV) is a highly infectious virus that represents a threat for domestic dogs and several wild species. Despite recognized in several African countries, current knowledge of its molecular epidemiology is scarce and poorly updated. DesignTwenty-two hemagglutinin sequences, obtained from symptomatic Namibian dogs from 2020 to 2023, were analysed through phylogenetic and phylodynamic analysis to characterize the local CDV epidemiology and contextualize it in the international scenario. ResultsTwo unrelated clades were identified, including strains sampled in different Namibian towns, in the absence of a strong geographical clustering. The ancestors of the two clades were estimated to have originated from South America, likely Brazil, and South Africa, approximately in 2000 and 2006, respectively. While the introduction from South Africa was predictable, the introduction from Brazil was unexpected. The mediation of other African countries, particularly Angola, appears to be the most likely importation pathway. ConclusionsThe occurrence of multiple introduction events, likely originating from cross-border illegal animal trade between African countries, and the absence of any geographical clustering within Namibian regions, suggest a need for further investigation into its spreading pattern, as well as improved biosecurity measures to limit foreign viral introduction into the country.

The impact of apicobasal ridges on dental load-bearing capacity in aquatic-feeding predatory amniotes

AbstractApicobasal ridges are longitudinal ridges of enamel that are particularly common in several clades of aquatic-feeding predatory amniotes, including Plesiosauria, Ichthyosauria, Mosasauridae, Crocodylia, and Spinosauridae, as well as some early members of Cetacea. Although the repeated evolution of these dental ridges in unrelated clades suggests an adaptive benefit, their primary function in feeding is debated. Hypothesized functions range from increasing tooth strength to improving prey puncture or removal efficiency, but these have never been quantitatively tested. This study utilizes finite element analysis (FEA) to assess the impact of apicobasal ridges upon tooth crown strength in aquatic-feeding amniotes. Drawing on morphometric data from fossilized tooth crowns, a set of digital models was constructed to calculate the performance of smooth and ridged tooth variants under simulated bite force loadings. The similarities in overall stress distribution patterns across models of the same tooth shape, regardless of the presence or morphology of ridges, indicate that apicobasal ridges have little impact on stress reduction within the tooth crown. Ultimately, these findings suggest that apicobasal ridges have a minimal role in improving crown strength and form a framework for future research into the remaining hypotheses.

Not the Last Piece of the Puzzle: Niphargus Phylogeny in Hungary

The Palaearctic genus Niphargus is a promising model system to understand subterranean fauna genesis in Europe. The Pannonian Plain (mainly covered by Hungary) in Central Europe, once being the area of the Paratethys, is a key area for Niphargus diversification. However, our knowledge on Hungarian species of Niphargus is primarily based on sporadic taxonomical works from the pre-molecular era. Here, we studied 14 localities, covering the eight valid Hungarian species of Niphargus and including nine previously unstudied populations. Based on sequences of three gene fragments, we reconstructed their phylogeny using maximum likelihood and Bayesian approaches. We found that not all Hungarian species of Niphargus are closely related, and even species sampled at the same localities can belong to different clades. Some Hungarian species form monophyletic clades, while others are nested in various non-Hungarian lineages. The new populations are all genetically distinct from the known species. Our results suggest that the Hungarian Niphargus fauna has originated from seven unrelated clades and its diversity is underestimated due to unknown populations and cryptic species. The detection of genetically distinct species of Niphargus from non-carbonate regions calls for further research efforts. The high diversity and the number of putative new species in the N. tatrensis clade warrants further, high-resolution phylogenetic studies.

Polyphyly of the genus Stenurella (Coleoptera, Cerambycidae): Consensus of morphological and molecular data

Stenurella genus is represented by nine small-sized and widely distributed Palaearctic species. Representatives of the genus play a key role in the pollination of wild angiosperms, accelerate the detritus cycle and make a significant contribution to the forest food web. A number of species with heterogeneous morphological features found within the single Stenurella genus indicate the need for revision of the taxonomy this genus. The previous attempt to resolve the intrageneric composition of Stenurella was rather artificial because it did not take into an account evolutionary relationships. In this study we tested the existing model of Stenurella intrageneric subdivision using both morphological and molecular approaches. Our results showed that the genus Stenurella is polyphyletic and consists of two unrelated clades. The first clade comprises six species (S. jaegeri, S. novercalis, S. bifasciata, S. melanura, S. hybridula and S. approximans) and the second includes three species (S. septempunctata, S. vaucheri and S. nigra). Moreover, we found that the second clade is closely related to Rutpela due to both morphological and molecular phylogeny. Based on our findings, we revised the present structure of the genus Stenurella and transferred three species of the second clade to the genus Rutpela, sensu novo. The genus Rutpela was redescribed in the light of our results. Furthermore, we subdivided the genus Stenurella, sensu nov. into two subgenera, Stenurella, subgen. sensu nov. and Priscostenurella, subgen. sensu nov., respectively. Also, the genus Rutpela, sensu nov. was subdivided into four subgenera including Nigrostenurella, Rutpela, Eduardvivesia, subgen. nov. and Nigromacularia, subgen. nov. The assessment of the place of Stenurella, sensu novo and Rutpela, sensu novo within Lepturini based on molecular phylogeny, showed that Stenurella, sensu novo belongs to the Anoplodera-branch and Rutpela, sensu novo nested within the Leptura-branch. These together with morphological features confirmed our idea of the evolutionary distinctiveness of Stenurella, sensu novo and Rutpela, sensu novo. We assumed that the general external morphological similarity of Stenurella, sensu novo and Rutpela, sensu novo was the result of convergent evolution, driven by mimetic selection toward imitation of ants or wasps. Finally, our study establishes a natural phylogenetic taxonomy of Stenurella.

Phylogenomic and comparative genomic analyses of Leuconostocaceae species: identification of molecular signatures specific for the genera Leuconostoc, Fructobacillus and Oenococcus and proposal for a novel genus Periweissella gen. nov.

The genera Convivina , Fructobacillus , Leuconostoc , Oenococcus and Weissella , which formed the family Leuconostocaceae , have recently been merged within the family Lactobacillaceae . Using genome sequences for 47 of the 52 named species from these genera, we report here comprehensive phylogenomic and comparative analyses on protein sequences from these species using multiple approaches. In a phylogenomic tree based on concatenated sequences of 498 core proteins from these five genera, and in a 16S rRNA gene tree, members of the genera Fructobacillus , Leuconostoc and Oenococcus formed distinct strongly supported clades. In contrast, Weissella species grouped into two distinct unrelated clades designated as the ‘ Weissella main clade’ and ‘ Weissella clade 2’. The presence of these clades is also seen in a matrix of pairwise average amino acid identity based on core protein sequences. In parallel, comparative genomic studies on protein sequences from Leuconostocaceae genomes have identified 46 conserved signature indels (CSIs) in diverse proteins that are unique characteristics of the different observed species clades. Of these identified CSIs, five, five and 13 CSIs are uniquely present in members of the genera Fructobacillus , Leuconostoc and Oenococcus , respectively. We also report here six and five CSIs that are exclusively present in the species from the Weissella main clade and Weissella clade 2, respectively, providing independent evidence supporting their distinctness from each other. The remaining 12 identified CSIs are commonly shared by some or all of the species from the genera Convivina , Fructobacillus and Leuconostoc , clarifying their interrelationships. The identified CSIs provide novel and reliable means for the identification/circumscription of members of the genera Fructobacillus , Leuconostoc and Oenococcus as well as the two Weissella species clades in molecular terms. Based on the strong phylogenetic and molecular evidence presented here, we propose that the genus Weissella be limited to only the species from the Weissell a main clade, whereas the species forming Weissella clade 2 should be transferred to a new genus Periweissella gen. nov.

The limits of convergence in the collective behavior of competing marine taxa.

Collective behaviors in biological systems such as coordinated movements have important ecological and evolutionary consequences. While many studies examine within‐species variation in collective behavior, explicit comparisons between functionally similar species from different taxonomic groups are rare. Therefore, a fundamental question remains: how do collective behaviors compare between taxa with morphological and physiological convergence, and how might this relate to functional ecology and niche partitioning? We examined the collective motion of two ecologically similar species from unrelated clades that have competed for pelagic predatory niches for over 500 million years—California market squid, Doryteuthis opalescens (Mollusca) and Pacific sardine, Sardinops sagax (Chordata). We (1) found similarities in how groups of individuals from each species collectively aligned, measured by angular deviation, the difference between individual orientation and average group heading. We also (2) show that conspecific attraction, which we approximated using nearest neighbor distance, was greater in sardine than squid. Finally, we (3) found that individuals of each species explicitly matched the orientation of groupmates, but that these matching responses were less rapid in squid than sardine. Based on these results, we hypothesize that information sharing is a comparably important function of social grouping for both taxa. On the other hand, some capabilities, including hydrodynamically conferred energy savings and defense against predators, could stem from taxon‐specific biology.

Homoplasy and morphological stasis revealed through multilocus phylogeny of new myrmecophilous species in Armadillidiidae (Isopoda: Oniscidea)

Abstract The terrestrial isopod family Armadillidiidae presents higher diversity in karstic areas, with fewer species present in areas with reduced suitable subterranean habitats, such as siliceous sandy soils. Myrmecophily, although not widespread in the family Armadillidiidae, can help these animals to colonize sandy substrates, as is observed in several populations of myrmecophilous Armadillidiidae species in central and southern Spain. Morphological examination and multilocus phylogenetic analyses, including mitochondrial DNA (Cox1) and nuclear DNA (18S, 28S and H3) markers, indicate that these myrmecophilous populations represent four new taxa: Iberiarmadillidium pinicola gen. & sp. nov., Iberiarmadillidium psammophilum sp. nov., Iberiarmadillidium sakura sp. nov. and Cristarmadillidium myrmecophilum sp. nov. Some of the main diagnostic characters used in the taxonomy of Armadillidiidae are not clearly apomorphic. Among head morphologies, Eluma type seems to be the ancestral state, being typical of several unrelated lineages; duplocarinate and Armadillidium types are derived states observed in unrelated lineages. The presence of a schisma is a convergent character state, because it has been identified in several taxa nested in unrelated clades. The newly described taxa present patterns of morphological stasis and homoplasy, likely to be associated with their shared myrmecophilous habits. The generic taxonomy of the family needs a deep revision including phylogenetic approaches and thorough taxon sampling.

Molecular phylogenetic analysis of the Prostanthera phylicifolia (Lamiaceae) assemblage resolves relationships of the ‘Critically Endangered’ P. gilesii and other putative new species

Prostanthera gilesii is a critically endangered species from the Central Tablelands of New South Wales. A conservation management strategy is currently underway for this species, whose phylogenetic affinities are not known. Morphologically, P. gilesii resembles P. phylicifolia and a population of uncertain identity from Evans Crown Nature Reserve in the Central Tablelands of New South Wales (P. sp. Evans Crown). The taxonomy of P. phylicifolia, however, is unclear. Prostanthera phylicifolia was described from populations in the Victorian Alps and Monaro; however, populations spanning from Victoria to southern Queensland have been variously identified as either P. phylicifolia or P. scutellarioides despite substantial geographic disjunctions and morphological dissimilarity. To examine the relationship between populations identified as P. phylicifolia, P. gilesii and P. sp. Evans Crown, nuclear (external transcribed spacer, ETS) and chloroplast (trnH-psbA intergenic spacer) regions were sequenced and combined with an existing Prostanthera dataset and analysed with maximum-likelihood and Bayesian-inference methods. Prostanthera gilesii and P. sp. Evans Crown were recovered as sister taxa within a clade consisting of populations morphologically similar to the type of P. phylicifolia from the Victorian Alps and Snowy Mountains, Monaro and Southern Tablelands of New South Wales. Populations from northern New South Wales and southern Queensland identified as P. phylicifolia or P. scutellarioides were recovered as an assemblage of unrelated clades. The molecular phylogeny supports P. gilesii and P. phylicifolia as closely related as hypothesised based on morphology and supports P. sp. Evans Crown as a population which requires additional study to assess its taxonomic status.

Evolution of habitat preference in 243 species of Bent-toed geckos (Genus Cyrtodactylus Gray, 1827) with a discussion of karst habitat conservation.

Understanding the processes that underpin adaptive evolutionary shifts within major taxonomic groups has long been a research directive among many evolutionary biologists. Such phenomena are best studied in large monophyletic groups that occupy a broad range of habitats where repeated exposure to novel ecological opportunities has happened independently over time in different lineages. The gekkonid genus Cyrtodactylus is just such a lineage with approximately 300 species that range from South Asia to Melanesia and occupy a vast array of habitats. Ancestral state reconstructions using a stochastic character mapping analysis of nine different habitat preferences were employed across a phylogeny composed of 76% of the known species of Cyrtodactylus. This was done in order to ascertain which habitat preference is the ancestral condition and from that condition, the transition frequency to more derived habitat preferences. The results indicate that a general habitat preference is the ancestral condition for Cyrtodactylus and the frequency of transitioning from a general habitat preference to anything more specialized occurs approximately four times more often than the reverse. Species showing extreme morphological and/or ecological specializations generally do not give rise to species bearing other habitat preferences. The evolution of different habitat preferences is generally restricted to clades that tend to occur in specific geographic regions. The largest radiations in the genus occur in rocky habitats (granite and karst), indicating that the transition from a general habitat preference to a granite or karst‐dwelling life style may be ecologically uncomplicated. Two large, unrelated clades of karst‐associated species are centered in northern Indochina and the largest clade of granite‐associated species occurs on the Thai‐Malay Peninsula. Smaller, independent radiations of clades bearing other habitat preferences occur throughout the tree and across the broad distribution of the genus. With the exception of a general habitat preference, the data show that karst‐associated species far out‐number all others (29.6% vs. 0.4%–10.2%, respectively) and the common reference to karstic regions as “imperiled arcs of biodiversity” is not only misleading but potentially dangerous. Karstic regions are not simply refugia harboring the remnants of local biodiversity but are foci of speciation that continue to generate the most speciose, independent, radiations across the genus. Unfortunately, karstic landscapes are some of the most imperiled and least protected habitats on the planet and these data continue to underscore the urgent need for their conservation.

Trait Variation in Moths Mirrors Small-Scaled Ecological Gradients in A Tropical Forest Landscape

Simple SummaryTropical rainforests are still lost at alarming rates due to timber extraction or conversion into plantations. While losses of species diversity are well documented, less is known about how the functional integrity of insect communities changes with such interventions. Using light-trap samples taken from species-rich moth assemblages in one region in SW Costa Rica, we asked whether the body size of moths and the contribution of warningly colored species change from old-growth forest across disturbed forest toward oil palm plantations. Across three topographic types of old-growth forest, differences were small. Moth species occurring in plantations were substantially smaller than their relatives thriving in natural forest. Similarly, the incidence of warning coloration dropped massively in plantations. Two different types of mimicry (moths imitating wasps or poisonous beetles, respectively) showed their own patterns of variation across ecosystems, yet both color types were very rare in plantations. These results confirm that not only insect species diversity becomes greatly diminished when tropical forests are destroyed: the functional composition and integrity of the insect fauna that remains in plantations is eroding as well.Along environmental gradients, communities are expected to be filtered from the regional species pool by physical constraints, resource availability, and biotic interactions. This should be reflected in species trait composition. Using data on species-rich moth assemblages sampled by light traps in a lowland rainforest landscape in Costa Rica, we show that moths in two unrelated clades (Erebidae-Arctiinae; Geometridae) are much smaller-sized in oil palm plantations than in nearby old-growth forest, with intermediate values at disturbed forest sites. In old-growth forest, Arctiinae predominantly show aposematic coloration as a means of anti-predator defense, whereas this trait is much reduced in the prevalence in plantations. Similarly, participation in Müllerian mimicry rings with Hymenoptera and Lycidae beetles, respectively, is rare in plantations. Across three topographic types of old-growth forests, community-weighted means of moth traits showed little variation, but in creek forest, both types of mimicry were surprisingly rare. Our results emphasize that despite their mobility, moth assemblages are strongly shaped by local environmental conditions through the interplay of bottom–up and top–down processes. Assemblages in oil palm plantations are highly degraded not only in their biodiversity, but also in terms of trait expression.

Resurrection of the Genus Heptapleurum for the Asian Clade of Species Previously Included in Schefflera (Araliaceae)

The polyphyly of the pantropical genus Schefflera J. R. Forst. & G. Forst. (Araliaceae) is now well established, and consequently the genus has had to be restricted to its type (S. digitata J. R. Forst. & G. Forst.) and seven closely related Pacific Island species. Taxonomic transfers of the members of four other, unrelated clades have mostly been completed, including those from Africa and Madagascar, the Neotropics, and Oceania. Here we treat the final and largest group, from Asia, reinstating the genus Heptapleurum Gaertn. for the 317 species that belong to the Asian clade of Schefflera. This synopsis provides 256 new combinations for 246 species and 10 varieties, along with one replacement name, and types are designated for five generic and infrageneric names. With the completion of these transfers, Heptapleurum is now the largest genus in Araliaceae.

Contrasting bacteriome of the hornwort Leiosporoceros dussii in two nearby sites with emphasis on the hornwort-cyanobacterial symbiosis

Symbioses between plants and nitrogen-fixing cyanobacteria are benchmark biological systems to understand mutualism and patterns of coevolution. The diversity of cyanobacteria associated to non-vascular land plants is still being unraveled, with a huge gap in knowledge from tropical areas, especially in hornworts. We focus on the Neotropical hornwort Leiosporoceros dussii, which has a semi-permanent association with cyanobacteria. Unlike other hornworts, the peculiar Nostoc canals suggest cyanobiont specificity and selectivity. Here, we characterize the first hornwort bacteriome and focus on the endophytic cyanobacteria by describing its morphology, metagenomic diversity and phylogeny between two sampling sites in Panama. First, we use a metagenomic analyses (16S) from gametophytes from Rio El Guayabo and Rio Indio in Panama to identify the endophytic bacteria community of L. dussii. To provide more information on the cyanobacterial endophytes, we have extracted cyanobacterial endophytes to measure cell size variation and use the markers trnL and rbcLX to determine their phylogenetic relationships. Finally, we use stable isotope δ 15N to assess nitrogen flow in the plants. We find little diversity in Leiosporoceros bacteriome but observe significant community variations between sites. Results indicate a lack of cyanobacterial specificity of cyanobacteria associated to Leiosporoceros, with six unrelated clades of Nostoc forming a polyphyletic assemblage. Four clades are nested within bacteria collected as free-living taxa suggesting that typically non-symbiotic cyanobacteria can be associated with this hornwort. Finally, the little nitrogen fractioning of the plant suggests the role of the cyanobacterial symbionts in nitrogen fixation. This study provides the first hornwort bacteriome and is an important step in the characterization of tropical bryophyte symbioses.

A new, fast method to search for morphological convergence with shape data.

Morphological convergence is an intensely studied macroevolutionary phenomenon. It refers to the morphological resemblance between phylogenetically distant taxa. Currently available methods to explore evolutionary convergence either: rely on the analysis of the phenotypic resemblance between sister clades as compared to their ancestor, fit different evolutionary regimes to different parts of the tree to see whether the same regime explains phenotypic evolution in phylogenetically distant clades, or assess deviations from the congruence between phylogenetic and phenotypic distances. We introduce a new test for morphological convergence working directly with non-ultrametric (i.e. paleontological) as well as ultrametric phylogenies and multivariate data. The method (developed as the function search.conv within the R package RRphylo) tests whether unrelated clades are morphologically more similar to each other than expected by their phylogenetic distance. It additionally permits using known phenotypes as the most recent common ancestors of clades, taking full advantage of fossil information. We assessed the power of search.conv and the incidence of false positives by means of simulations, and then applied it to three well-known and long-discussed cases of (purported) morphological convergence: the evolution of grazing adaptation in the mandible of ungulates with high-crowned molars, the evolution of mandibular shape in sabertooth cats, and the evolution of discrete ecomorphs among anoles of Caribbean islands. The search.conv method was found to be powerful, correctly identifying simulated cases of convergent morphological evolution in 95% of the cases. Type I error rate is as low as 4–6%. We found search.conv is some three orders of magnitude faster than a competing method for testing convergence.

Phylogenetic re-evaluation of Thielavia with the introduction of a new family Podosporaceae.

The genus Thielavia is morphologically defined by having non-ostiolate ascomata with a thin peridium composed of textura epidermoidea, and smooth, single-celled, pigmented ascospores with one germ pore. Thielavia is typified with Th. basicola that grows in close association with a hyphomycete which was traditionally identified as Thielaviopsis basicola. Besides Th. basicola exhibiting the mycoparasitic nature, the majority of the described Thielavia species are from soil, and some have economic and ecological importance. Unfortunately, no living type material of Th. basicola exists, hindering a proper understanding of the classification of Thielavia. Therefore, Thielavia basicola was neotypified by material of a mycoparasite presenting the same ecology and morphology as described in the original description. We subsequently performed a multi-gene phylogenetic analyses (rpb2, tub2, ITS and LSU) to resolve the phylogenetic relationships of the species currently recognised in Thielavia. Our results demonstrate that Thielavia is highly polyphyletic, being related to three family-level lineages in two orders. The redefined genus Thielavia is restricted to its type species, Th. basicola, which belongs to the Ceratostomataceae (Melanosporales) and its host is demonstrated to be Berkeleyomyces rouxiae, one of the two species in the “Thielaviopsis basicola” species complex. The new family Podosporaceae is sister to the Chaetomiaceae in the Sordariales and accommodates the re-defined genera Podospora, Trangularia and Cladorrhinum, with the last genus including two former Thielavia species (Th. hyalocarpa and Th. intermedia). This family also includes the genetic model species Podospora anserina, which was combined in Triangularia (as Triangularia anserina). The remaining Thielavia species fall in ten unrelated clades in the Chaetomiaceae, leading to the proposal of nine new genera (Carteria, Chrysanthotrichum, Condenascus, Hyalosphaerella, Microthielavia, Parathielavia, Pseudothielavia, Stolonocarpus and Thermothielavioides). The genus Canariomyces is transferred from Microascaceae (Microascales) to Chaetomiaceae based on its type species Can. notabilis. Canariomyces is closely related to the human-pathogenic genus Madurella, and includes three thielavia-like species and one novel species. Three monotypic genera with a chaetomium-like morph (Brachychaeta, Chrysocorona and Floropilus) are introduced to better resolve the Chaetomiaceae and the thielavia-like species in the family. Chrysocorona lucknowensis and Brachychaeta variospora are closely related to Acrophialophora and three newly introduced genera containing thielavia-like species; Floropilus chiversii is closely related to the industrially important and thermophilic species Thermothielavioides terrestris (syn. Th. terrestris). This study shows that the thielavia-like morph is a homoplastic form that originates from several separate evolutionary events. Furthermore, our results provide new insights into the taxonomy of Sordariales and the polyphyletic Lasiosphaeriaceae.

Frogs and tuns and tritons – A molecular phylogeny and revised family classification of the predatory gastropod superfamily Tonnoidea (Caenogastropoda)

The Tonnoidea is a moderately diverse group of large, predatory gastropods with ∼360 valid species. Known for their ability to secrete sulfuric acid, they use it to prey on a diversity of invertebrates, primarily echinoderms. Tonnoideans currently are classified in seven accepted families: the comparatively well known, shallow water Bursidae, Cassidae, Personidae, Ranellidae, and Tonnidae, and the lesser-known, deep water Laubierinidae and Pisanianuridae. We assembled a mitochondrial and nuclear gene (COI, 16S, 12S, 28S) dataset for ∼80 species and 38 genera currently recognized as valid. Bayesian analysis of the concatenated dataset recovered a monophyletic Tonnoidea, with Ficus as its sister group. Unexpectedly, Thalassocyon, currently classified in the Ficidae, was nested within the ingroup as the sister group to Distorsionella. Among currently recognized families, Tonnidae, Cassidae, Bursidae and Personidae were supported as monophyletic but the Ranellidae and Ranellinae were not, with Cymatiinae, Ranella and Charonia supported as three unrelated clades. The Laubierinidae and Pisanianuridae together form a monophyletic group. Although not all currently accepted genera have been included in the analysis, the new phylogeny is sufficiently robust and stable to the inclusion/exclusion of nonconserved regions to establish a revised family-level classification with nine families: Bursidae, Cassidae, Charoniidae, Cymatiidae, Laubierinidae, Personidae, Ranellidae, Thalassocyonidae and Tonnidae. The results reveal that many genera as presently circumscribed are para- or polyphyletic and, in some cases support the rescue of several genus-group names from synonymy (Austrosassia, Austrotriton, Laminilabrum, Lampadopsis, Personella, Proxicharonia, Tritonoranella) or conversely, support their synonymization (Biplex with Gyrineum). Several species complexes are also revealed that merit further investigation (e.g., Personidae: Distorsio decipiens, D. reticularis; Bursidae: Bursa tuberosissima; Cassidae: Echinophoria wyvillei, Galeodea bituminata, and Semicassis bisulcata). Consequently, despite their teleplanic larvae, the apparently circumglobal distribution of some tonnoidean species is the result of excessive synonymy. The superfamily is estimated to have diverged during the early Jurassic (∼186 Ma), with most families originating during a narrow ∼20 My window in Albian-Aptian times as part of the Mesozoic Marine Revolution.

DNA barcoding of the medically important freshwater snail Physa acuta reveals multiple invasion events into Africa

The medically important freshwater snail Physa acuta is highly invasive and has been reported in several freshwater environments across Africa. To identify species and provide initial insights into the origins of P. acuta into African freshwater environments standard molecular barcoding analyses, using the mitochondrial cytochrome c oxidase subunit I gene (COI), was performed on P. acuta isolates from Angola, Burundi and South Africa. Phylogenetic analyses of isolates from Africa could not be distinguished from P. acuta populations from other countries. Comparisons of COI sequences between isolates of P. acuta showed there to be no geographically specific clusters and the African isolates were distributed across four distinct unrelated clades suggesting several independent invasion events. Haplotype analyses indicated that there were a high number of haplotypes with low variation between them, which led to significant differences in AMOVA analyses between countries. This was further evidence of multiple invasion events suggesting multiple novel haplotypes being continually and independently introduced to each country. This approach not only provides initial insight into the invasion of Africa by P. acuta but a molecular method to monitor and manage the use of an agent of biological control.

Understanding processes at the origin of species flocks with a focus on the marine Antarctic fauna.

Species flocks (SFs) fascinate evolutionary biologists who wonder whether such striking diversification can be driven by normal evolutionary processes. Multiple definitions of SFs have hindered the study of their origins. Previous studies identified a monophyletic taxon as a SF if it displays high speciosity in an area in which it is endemic (criterion 1), high ecological diversity among species (criterion 2), and if it dominates the habitat in terms of biomass (criterion 3); we used these criteria in our analyses. Our starting hypothesis is that normal evolutionary processes may provide a sufficient explanation for most SFs. We thus clearly separate each criterion and identify which biological (intrinsic) and environmental (extrinsic) traits are most favourable to their realization. The first part focuses on evolutionary processes. We highlight that some popular putative causes of SFs, such as key innovations or ecological speciation, are neither necessary nor sufficient to fulfill some or all of the three criteria. Initial differentiation mechanisms are diverse and difficult to identify a posteriori because a primary differentiation of one type (genetic, ecological or geographical) often promotes other types of differentiation. Furthermore, the criteria are not independent: positive feedbacks between speciosity and ecological diversity among species are expected whatever the initial cause of differentiation, and ecological diversity should enhance habitat dominance at the clade level. We then identify intrinsic and extrinsic factors that favour each criterion. Low dispersal emerges as a convincing driver of speciosity. Except for a genomic architecture favouring ecological speciation, for which assessment is difficult, high effective population sizes are the single intrinsic factor that directly enhances speciosity, ecological diversity and habitat dominance. No extrinsic factor appeared to enhance all criteria simultaneously but a combination of factors (insularity, fragmentation and environmental stability) may favour the three criteria, although the effect is indirect for habitat dominance. We then apply this analytical framework to Antarctic marine environments by analysing data from 18 speciose clades belonging to echinoderms (five unrelated clades), notothenioid fishes (five clades) and peracarid crustaceans (eight clades). Antarctic shelf environments and history appear favourable to endemicity and speciosity, but not to ecological specialization. Two main patterns are distinguished among taxa. (i) In echinoderms, many brooding, species-rich and endemic clades are reported, but without remarkable ecological diversity or habitat dominance. In these taxa, loss of the larval stage is probably a consequence of past Antarctic environmental factors, and brooding is suggested to be responsible for enhanced allopatric speciation (via dispersal limitation). (ii) In notothenioids and peracarids, many clades fulfill all three SF criteria. This could result from unusual features in fish and crustaceans: chromosome instability and key innovations (antifreeze proteins) in notothenioids, ecological opportunity in peracarids, and a genomic architecture favouring ecological speciation in both groups. Therefore, the data do not support our starting point that normal evolutionary factors or processes drive SFs because in these two groups uncommon intrinsic features or ecological opportunity provide the best explanation. The utility of the three-criterion SF concept is therefore questioned and guidelines are given for future studies.

The biomechanical consequences of longirostry in crocodilians and odontocetes

Unrelated clades of aquatic tetrapod have evolved a similar range of skull shapes, varying from longirostrine (elongate and narrow rostrum) to brevirostrine (short rostrum). However, it is unclear which aspects of organismal performance are associated with this convergence in the range of skull shapes. Furthermore, it is not known how fundamental anatomical differences between groups influence these relationships. Here we address this by examining the load bearing capabilities of the skulls of two of the most diverse groups of living aquatic tetrapod: crocodilians and odontocetes. We use finite element analysis to examine the abilities of different cranial morphologies to resist a range of biologically relevant feeding loads including biting, shaking and twisting. The results allow for form/function relationships to be compared and contrasted between the two groups. We find that cranial shape has similar influences on performance during biting, shaking or twisting load cases at the anterior tooth positions, e.g. brevirostrine species experienced less strain than longirostrine species. The pattern of this form/function relationship is similar for both crocodilians and odontocetes, despite their fundamentally different anatomies. However, when loading teeth at the posterior end or middle of the tooth row the results do not follow the same pattern. Behavioural differences in bite location plays a key role in determining functional abilities in aquatic tetrapod taxa.

Biogeography and diversification dynamics of the African woodpeckers

The dynamics of species accumulation of African terrestrial vertebrates over time remains underexplored in comparison with those in the New World, despite Africa hosting about 25% of the world’s avian diversity. This lack of knowledge hampers our understanding of the fundamental processes that drive biodiversity and the dynamics of speciation. To begin to address this gap, we reconstructed species-level phylogenies of two unrelated clades of African woodpeckers (12 species of Geocolaptes/Campethera and 13 species of Chloropicus/Mesopicos/Dendropicos/Ipophilus) that diverged from their closest Indo-Malayan relatives at similar times. Our results demonstrate that the current taxonomy is misleading: three (Campethera, Dendropicos and Mesopicos) out of four polytpic genera/subgenera are not monophyletic. Our results also show that current estimates of diversity at the species level are significantly understated, as up to 18 species for the ‘Campethera clade’ and 19 for the ‘Dendropicos clade’ could be recognized. The first splits within both clades involve species that are largely restricted to the Guineo-Congolian biogeographic regions, followed by later adaptations to particular habitats (forest versus savannah) and colonization of other regions (e.g. Southern Africa), each of which occurred multiple times in both clades. Assuming a conservative species delimitation scheme, our results indicate that diversification rates are decreasing through time for both clades. Applying a more extreme species recognition scheme (18 and 19 species for the Campethera and Dendropicos clades, respectively), our results support a decrease in diversification rates only for the Dendropicos clade and thus underline the importance of the number of species included in our diversification analyses. Greater ecological diversity of the Campethera clade where multiple species exhibit either an arboreal or terrestrial foraging strategy might explain the constant diversification rates through time we found under the eighteen species scheme.