scholarly journals Phenotypic differentiation of the slow worm lizards (Squamata: Anguis) across their contact zone in Central Europe

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12482
Author(s):  
Norbert Benkovský ◽  
Jiří Moravec ◽  
Veronika Gvoždíková Javůrková ◽  
Helena Šifrová ◽  
Václav Gvoždík ◽  
...  

Background The application of molecular-phylogenetic approaches to taxonomy has had a dramatic effect on our understanding of the diversity of reptiles. These approaches have allowed researchers to reveal previously hidden lineages as well as taxonomic overestimation in morphologically plastic taxa. Slow worms, legless lizards of the genus Anguis (Squamata: Anguidae), were previously considered to comprise either one or two species, and morphology-based intraspecific taxonomy of Anguis fragilis remained controversial throughout the 20th century. After the discovery of deep genetic divergences within the genus, its taxonomy was reconsidered, and as a result, five extant species have been recognized. In order to better understand the patterns of their interspecific differentiation, here we studied phenotypic differences between the two most widespread of them—A. fragilis and A. colchica, and their putative hybrids across the contact zone of both species in Central Europe. Methods We used multivariate and univariate statistics and analyzed ten metric, eleven meristic, and six categorical phenotypic variables in material comprising a total of 326 individuals. We also genotyped individuals from the contact zone for one mitochondrial and two nuclear DNA fragments in order to delineate the distribution of individuals of hybrid and non-hybrid origin. The clines in morphological traits were studied using HZAR. Results We show that the two species are morphologically differentiated. Anguis fragilis has a less robust head, fewer scales covering the body, lower frequency of the external ear opening presence, lower frequency of separated prefrontal scales, higher frequency of prefrontal scales in contact with each other, and body coloration more similar to the juvenile coloration than A. colchica. Slow worms from the contact/hybrid zone are characterized by an intermediate morphology, with more similarities to A. fragilis than to A. colchica. Discussion None of the analyzed characters alone proved to be fully diagnostic, although more than 90% of all individuals could be successfully assigned to one or another species based on numbers of scales around the body. Our results indicate concordant, coincident, and steep clines in character states change. We present several hypotheses on the origin and evolutionary maintenance of the morphological divergence between both species and suggest that different evolutionary histories of the taxa rather than recently acting selection explain the observed morphological variation.

ZooKeys ◽  
2020 ◽  
Vol 943 ◽  
pp. 119-144 ◽  
Author(s):  
Ning Xu ◽  
Shi-Ze Li ◽  
Jing Liu ◽  
Gang Wei ◽  
Bin Wang

A new species of the genus Megophrys is described from Guizhou Province, China. Molecular phylogenetic analyses based on mitochondrial DNA and nuclear DNA sequences all strongly supported the new species as an independent clade sister to M. minor and M. jiangi. The new species could be distinguished from its congeners by a combination of the following characters: body size moderate (SVL 43.4–44.1 mm in males, and 44.8–49.8 mm in females; vomerine teeth absent; tongue not notched behind; a small horn-like tubercle at the edge of each upper eyelid; tympanum distinctly visible, rounded; two metacarpal tubercles on palm; relative finger lengths II < I < V < III; toes without webbing; heels overlapping when thighs are positioned at right angles to the body; tibiotarsal articulation reaching the level between tympanum and eye when leg stretched forward; in breeding males, an internal single subgular vocal sac in male, and the nuptial pads with black spines on dorsal surface of bases of the first two fingers.


2017 ◽  
Vol 38 (4) ◽  
pp. 562-569 ◽  
Author(s):  
Daniel Jablonski ◽  
Bartłomiej Najbar ◽  
Renata Grochowalska ◽  
Václav Gvoždík ◽  
Tomasz Strzała

Five slow-worm species are distributed in the Palearctic region. Two species, Anguis fragilis and A. colchica, are native to Central Europe, where only limited information on the phylogeography of the genus exists. Here, we examined the situation in Poland and surrounding regions, where a mitochondrial contact zone between the species is expected. We used new mitochondrial DNA sequences and available published data from Central Europe and the northern Balkans. Haplotypes of both species were recorded in the study area. Anguis fragilis is represented by a single haplogroup, while A. colchica by three haplogroups. This suggests four independent sources/refugia for postglacial colonization of northern Central Europe. The mitochondrial contact zone seems to mirror the borders between lowlands of the North European Plain and East European Plain, and the south-eastern Poland uplands, while the Vistula River does not constitute a barrier. The presence of both species, A. fragilis and A. colchica, in Poland should also be considered for protection by the Polish conservation legislation.


2021 ◽  
pp. 1-7
Author(s):  
Václav Gvoždík ◽  
Zdeněk Harca ◽  
Alexandra Hánová ◽  
Daniel Jablonski ◽  
Mihails Pupins ◽  
...  

Abstract Five European slow worms (Anguis) have mostly parapatric distributions. Two species, A. fragilis and A. colchica, are widely distributed across the western and eastern parts of the genus range. Their contact zone runs from the north-eastern Balkans, through Pannonia to northern Central Europe. In northern Poland, the contact zone has been located approximately between the North and East European Plains. Here, we present the first mitochondrial and nuclear DNA data from Finland and the coastal Baltics. We demonstrate that A. fragilis enters the East European Plains, where it is presumably distributed along the Baltic coast. Our data indicate that A. colchica is present more inland and to the north of Riga. The genetic structure suggests three independent postglacial colonization events in the Baltics (two by A. colchica). The presence of the two species, A. fragilis and A. colchica, should be considered by the conservation legislations of Lithuania, Latvia and Russia.


Birds ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 138-146
Author(s):  
Eduardo J. Rodríguez-Rodríguez ◽  
Juan J. Negro

The family Ciconiidae comprises 19 extant species which are highly social when nesting and foraging. All species share similar morphotypes, with long necks, a bill, and legs, and are mostly coloured in the achromatic spectrum (white, black, black, and white, or shades of grey). Storks may have, however, brightly coloured integumentary areas in, for instance, the bill, legs, or the eyes. These chromatic patches are small in surface compared with the whole body. We have analyzed the conservatism degree of colouration in 10 body areas along an all-species stork phylogeny derived from BirdTRee using Geiger models. We obtained low conservatism in frontal areas (head and neck), contrasting with a high conservatism in the rest of the body. The frontal areas tend to concentrate the chromatic spectrum whereas the rear areas, much larger in surface, are basically achromatic. These results lead us to suggest that the divergent evolution of the colouration of frontal areas is related to species recognition through visual cue assessment in the short-range, when storks form mixed-species flocks in foraging or resting areas.


The Auk ◽  
2021 ◽  
Author(s):  
Scott F Lovell ◽  
M Ross Lein ◽  
Sean M Rogers

Abstract Eastern (Vireo gilvus gilvus) and western (V. g. swainsoni) forms of the Warbling Vireo have essentially allopatric breeding ranges across north-central North America, but come into contact in central Alberta, Canada. In 1986, Jon Barlow presented preliminary morphological and song evidence suggesting that the Warbling Vireo complex might comprise more than one valid species. However, to date, Barlow’s suggestion is supported by only limited DNA evidence, demonstration of molt and migration differences between the taxa, and anecdotal accounts of differences in song, morphology, plumage, and ecology. We analyzed variation in both mitochondrial and nuclear DNA in birds from Alberta and surrounding areas to determine the levels of genetic differentiation and hybridization occurring in the contact zone, and whether the two taxa warrant recognition as separate biological species. Our analyses reveal that Warbling Vireos in Alberta and the surrounding areas are separated into two well-defined, genetically differentiated, and monophyletic clades corresponding to previously recognized taxonomic groups. The two taxa come into contact in a narrow (~85 km) zone in Barrhead County, northwest of Edmonton, Alberta. They show evidence of limited hybridization. The distinct genetic differences are maintained in the contact zone, where individuals of the two taxa may occupy neighboring territories. Differences in spring arrival dates, molt schedules, and migration routes indicate that a migratory divide may play an important role in reproductive isolation. We suggest that the two taxa are distinct cryptic species: an eastern form, Vireo gilvus, and a western form, Vireo swainsoni.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Jimi ◽  
Shinta Fujimoto ◽  
Mami Takehara ◽  
Satoshi Imura

AbstractThe phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species’ body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species’ spicules and also the species' progenetic origin.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4790 ◽  
Author(s):  
Abhimanyu S. Ahuja

Mitochondria are small, energy-producing structures vital to the energy needs of the body. Genetic mutations cause mitochondria to fail to produce the energy needed by cells and organs which can cause severe disease and death. These genetic mutations are likely to be in the mitochondrial DNA (mtDNA), or possibly in the nuclear DNA (nDNA). The goal of this review is to assess the current understanding of mitochondrial diseases. This review focuses on the pathology, causes, risk factors, symptoms, prevalence data, symptomatic treatments, and new research aimed at possible preventions and/or treatments of mitochondrial diseases. Mitochondrial myopathies are mitochondrial diseases that cause prominent muscular symptoms such as muscle weakness and usually present with a multitude of symptoms and can affect virtually all organ systems. There is no cure for these diseases as of today. Treatment is generally supportive and emphasizes symptom management. Mitochondrial diseases occur infrequently and hence research funding levels tend to be low in comparison with more common diseases. On the positive side, quite a few genetic defects responsible for mitochondrial diseases have been identified, which are in turn being used to investigate potential treatments. Speech therapy, physical therapy, and respiratory therapy have been used in mitochondrial diseases with variable results. These therapies are not curative and at best help with maintaining a patient’s current abilities to move and function.


2021 ◽  
pp. 20-23
Author(s):  
S. V. Pashukevich ◽  

The work conducts laboratory tests on the rubber of the first group of GOST 8752-70 with the introduction of the metal components. The filler is introduced into the rubber mixture on laboratory rollers. Fine powders of copper (Cu), tin (Sn) and lead (Pb) are used as fillers. The dependences of the temperature in the contact zone of the sample and the body of revolution on the concentration of the filler and the dependence of wear on the concentration of the filler for the same loads and sliding speeds are obtained, the fillers that give the rubber the greatest wear resistance are revealed, and the rational amount of the filler is determined. The positive results of laboratory tests give grounds to recommend various equipment including aerospace equipment for use in sealing devices of hydraulic systems, rubber products with metal fillers in the indicated concentrations, which will extend their service life and increase their reliability


2012 ◽  
Vol 279 (1737) ◽  
pp. 2396-2401 ◽  
Author(s):  
Rachunliu G. Kamei ◽  
Diego San Mauro ◽  
David J. Gower ◽  
Ines Van Bocxlaer ◽  
Emma Sherratt ◽  
...  

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India—an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.


Author(s):  
Shûhei YAMAMOTO ◽  
Alexey V. SHAVRIN ◽  
Kristaps KAIRIŠS

ABSTRACT Phloeocharinae is a small and likely non-monophyletic subfamily of rove beetles. The enigmatic genus Charhyphus Sharp, 1887 has long been placed in Phloeocharinae, whereas recent studies have found it to be phylogenetically very distant from the core members of this subfamily, suggesting the possibility that it actually deserves its own separate subfamily status. So far, the sole definitive fossil record for Charhyphus is known based on a single male from Eocene Baltic amber as represented by †Charhyphus balticus Shavrin, 2020. Here, we describe and illustrate another new Charhyphus species, †Charhyphus serratus sp. nov. Yamamoto & Shavrin, from Baltic amber based on a well-preserved female fossil. Considering the general proportions of the body and the head, this new species is most similar to †C. balticus. The new species differs from all known species by the development of strong serration of the lateral edges of the pronotum and features of the shape of the apical margin of the mesoventrite. By using X-ray micro-computed tomography, we succeeded in visualising not only the general habitus but also each individual body part, recovering a previously undocumented sclerite on the female internal genital segments in the genus. Morphological features of extinct and extant species of Charhyphus are briefly discussed. Figures of all extant Charhyphus species and a key for the genus are also provided. Our study is important for considering possible higher palaeodiversity, more common occurrence, and palaeobiogeography of Charhyphus.


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