Character States Research Articles

Proposal for All-Electrical Skyrmion Detection in van der Waals Tunnel Junctions.

A major challenge for magnetic skyrmions in atomically thin van der Waals (vdW) materials is reliable skyrmion detection. Here, based on rigorous first-principles calculations, we show that all-electrical skyrmion detection is feasible in two-dimensional vdW magnets via scanning tunneling microscopy (STM) and in planar tunnel junctions. We use the nonequilibrium Green's function method for quantum transport in planar junctions, including self-energy due to electrodes and working conditions, going beyond the standard Tersoff-Hamann approximation. We obtain a very large tunneling anisotropic magnetoresistance (TAMR) around the Fermi energy for a graphite/Fe3GeTe2/germanene/graphite vdW tunnel junction. For atomic-scale skyrmions, the noncollinear magnetoresistance (NCMR) reaches giant values. We trace the origin of the NCMR to spin mixing between spin-up and -down states of pz and dz2 character at the surface atoms. Both TAMR and NCMR are drastically enhanced in tunnel junctions with respect to STM geometry due to orbital symmetry matching at the interface.

Nothing to it: a reply to Wheeler's "much ado about nothing".

Wheeler (Cladistics 2023, 39, 475) recently suggested that the issues with inapplicable characters in phylogenetic analysis can be dealt with directly by treating observed absences of a feature not in a separate absence/presence character but as insertion/deletion events in a complex character that describes the feature in all its variation; and that this dynamic homology view can be achieved by imposing a sequence or linear order on a set of characters and by analysing the resulting sequence character using custom alphabet tree alignment algorithms. As Wheeler observed, this approach can lead to considering inappropriate character states (such as a head state and a foot state) homologous. We show that it is also sensitive to the specific ordering assumption used and that such different character orders can lead to a preference for different trees. We present a simple four-taxon dataset with observations of absence, but no inapplicable characters or other kinds of character dependence, for which the dynamic homology framework gives different results to classic algorithms for independent characters, including an optimal tree with biologically impossible reconstructions at inner nodes (every terminal has a head but the inner nodes are headless). We show how these issues can be solved by removing the character ordering assumption that the approach requires. Doing so, the dynamic homology framework reduces in general to Maddison's (Syst. Biol. 1993, 42, 576) well-known proposal to deal with inapplicability using step matrix analysis of complex characters. If in addition costs are interpreted in terms of homology, it reduces to Goloboff et al.'s (Cladistics 2021, 37, 596) step matrix implementation for maximization of homology as applied to inapplicable characters. However, if used with homogeneous costs, as Wheeler suggested, it reduces to unordered analysis of such complex characters, which is known to treat tails that may share many observed features as irrelevant for establishing kinship when they differ in just one feature, e.g. colour.

Функционально-прагматический аспект использования парафонационных средств при выражении эмоционального состояния персонажа в романе И. С. Тургенева «Отцы и дети»

The aim of the study is to identify the functional and semantic potential of paraphonation tools for representing the emotional state of characters. The paper examines the paraphonation tools that function in I. S. Turgenev’s novel “Fathers and Sons”: verbs of speech action that have a semantic potential for expressing emotional states; specifiers complementing verbs that do not have an emotive seme in the lexical meaning; figurative names such as epithets and metaphors. The authors emphasize that the functional and semantic potential of paraphonation tools is fully precisely in the context, which allows for the semantic accuracy of emotional state description. Particular attention is paid to the contexts in which emotions are expressed by a combination of paraphonation tools and other elements of the paralinguistic system: parakinemes, paraproxemes, etc. The paper also analyzes the author’s description of phonation phenomena such as sighing, laughter, silence, which act as markers of specific emotional states. The scientific novelty lies in the fact that the paraphonation tools considered in the functional and pragmatic aspect, firstly, realize the emotive potential in a literary text to varying degrees and, secondly, affect the reader’s perception of the meanings of the text and provide a correct understanding of the author’s intention as a whole. As a result of the study, the features of paraphonation tools performing the function of representing the emotional state of characters, specifying emotions, creating a psychological portrait of a character were revealed.

A new Chinese Cyclogethes pollen beetle, with an updated key to species of the genus and notes on its phylogenetic positioning (Coleoptera: Nitidulidae: Meligethinae).

A peculiar new species of the genus Cyclogethes Kirejtshuk, 1979, C. tibialis sp. nov., is described from Southwestern China (Yunnan). The new species appears to be morphologically rather isolated from the other known members of this essentially Oriental genus (including half a dozen species from Northern Indian subcontinent, Northern Indochina, and Southwestern China). However, it could be more closely related to C. abnormis Kirejtshuk, 1979 from Northern India, Indochina, and Southwestern China, and to C. aldridgei Kirejtshuk, 1980 from Northern India and Nepal, from which it is easily distinguished by the more elongate body shape, and by the markedly sinuate hind tibiae in both sexes (a very unusual character state in Meligethinae, where only males of some species exhibit sexual secondary characters in the tibial shape). The new species also differs from other known taxa of the genus by the shape of the male and female genitalia. The larval hostplants of members of Cyclogethes are thus far unknown, although some clues, also involving the new species described herein, may suggest a relationship with small trees or shrubs of the family Asteraceae. Preliminary and incomplete molecular data on a studied member of the genus (C. abnormis) seems to not disagree with a phylogenetic positioning of Cyclogethes in a clade including the African genera Tarchonanthogethes Audisio & Cline, 2009, its allied Afrotropical taxa, and the Palaearctic genera Meligethes Stephens, 1830 and Brassicogethes Audisio & Cline, 2009. The article includes an updated identification key for all six known species of this genus and an updated map of their known geographic distribution.

Redescription of the tiger beetle Cicindelidia aeneicollis (Bates 1881) (Coleoptera: Cicindelidae) and discovery of new morphological variants from the Pacific Slope of Mexico.

The tiger beetle species, Cicindelidia aeneicollis (Bates 1881) is redescribed, as Bates original description was inadequate and did not accurately capture the character states or variation found within the species. The specific epithet aeneicollis is partially misleading as the proepisternum is mostly aeneous (bronze/copper) with the basal quarter to third being polychromatic, which the description does not convey. Some populations of this species from the western coast of Mexico exhibit significant variation in maculations, with individuals ranging from weakly marked (as in Bates description) to much more extensively marked.

The osteology of Shuvosaurus inexpectatus, a shuvosaurid pseudosuchian from the Upper Triassic Post Quarry, Dockum Group of Texas, USA.

A vast array of pseudosuchian body plans evolved during the diversification of the group in the Triassic Period, but few can compare to the toothless, long-necked, and bipedal shuvosaurids. Members of this clade possess theropod-like character states mapped on top of more plesiomorphic pseudosuchian character states, complicating our understanding of the evolutionary history of the skeleton. One taxon in this clade, Shuvosaurus inexpectatus has been assigned to various theropod dinosaur groups based on a partial skull and referred material and its postcranium was assigned to a different taxon in Pseudosuchia. After the discovery of a skeleton of a shuvosaurid with a Shuvosaurus-like skull and a pseudosuchian postcranial skeleton, it became clear Shuvosaurus inexpectatus was a pseudosuchian. Nevertheless, a number of questions have arisen about what skeletal elements belonged to Shuvosaurus inexpectatus, the identification of skull bones, and the resulting implication for pseudosuchian evolution. Here, we detail the anatomy of the skeleton Shuvosaurus inexpectatus through a critical lens, parse out the bones that belong to the taxon or those that clearly do not or may not belong to the taxon, rediagnose the taxon based on these revisions, and compare the taxon to other archosaurs. We find that Shuvosaurus inexpectatus possesses similar anatomy to other shuvosaurids but parts of the skeleton of the taxon clarifies the anatomy of the group given that they are preserved in Shuvosaurus inexpectatus but not in others. Shuvosaurus inexpectatus is represented by at least 14 individuals from the West Texas Post Quarry (Adamanian holochronozone) and all Shuvosaurus inexpectatus skeletal material from the locality pertains to skeletally immature individuals. All of the skeletons are missing most of the neural arches, ribs, and most of the forelimb. We only recognize Shuvosaurus inexpectatus from the Post Quarry and all other material assigned to the taxon previously is better assigned to the broader group Shuvosauridae.

The postcranial skeleton of Teyujagua paradoxa (Reptilia: Archosauromorpha) from the early Triassic of South America.

Teyujagua paradoxa is a remarkable early archosauromorph from the Lower Triassic Sanga do Cabral Formation, Brazil. The species was originally described from an almost complete skull and a few associated cervical vertebrae, and no further postcranial elements were known at that time. Additional fieldwork in the Sanga do Cabral Formation, however, was successful in recovering a fairly complete postcranial skeleton attributable to the holotype. Here, we describe this new postcranial material, which is composed of cervical, dorsal, sacral and caudal vertebrae, limbs, pectoral and pelvic girdles, ribs, and gastralia. The description of its postcranial skeleton makes T. paradoxa one of the best-known early-diverging archosauromorphs. The cladistic analysis performed after the scoring of postcranial data recovered T. paradoxa in the same position initially described, close to the node that defines the Archosauriformes. Teyujagua paradoxa shares morphological features with representatives of early-diverging archosauromorphs and archosauriforms, with certain traits demonstrating a mosaic of plesiomorphic and apomorphic character states. We also performed partitioned morphospace and disparity analysis to elucidate the morphological disparity and evolutionary patterns among archosauromorphs. Teyujagua paradoxa occupies a notable position, suggesting an intermediate morphology between early archosauromorphs and proterosuchids. Disparity estimates highlighted Pseudosuchia and Avemetatarsalia as having the highest median disparity, reflecting their diverse cranial and postcranial morphologies, respectively. These findings offer valuable insights into archosauromorph macroevolution and adaptation.

Morphological Diversity of Turtle Hyoid Apparatus is Linked to Feeding Behavior.

The hyoid apparatus of tetrapods is highly diverse in its morphology. It plays an important role in feeding, breathing, sound production, and various other behaviors. Among turtles, the diversity of the hyoid apparatus has been recurrently linked to their habitat. The ossification of the hyoid corpus is often the main trait used in correlations with "niche" occupancy, an ossified corpus being associated with aquatic environments and a cartilaginous corpus with terrestrial life. Most studies conducted so far have focused on species belonging to Testudinoidea, the clade that occupies the biggest diversity of habitats (i.e., terrestrial, semi-terrestrial, and aquatic animals), while other turtle lineages have been largely understudied. We assessed the adult anatomy of the hyoid apparatus of 92 turtle species from all "families", together with ossification sequences from embryological series of 11 species, some described for the first time here. Using nearly 40 different discrete anatomical characters, we discuss the evolutionary patterns and the biological significance of morphological transformations in the turtle hyoid elements. Morphological changes are strongly associated to feeding modes, with several instances of convergent evolution within and outside the Testudines clade, and are not as strongly connected to habitat as previously thought. Some of the hyoid character states we describe are diagnostic of specific turtle clades, thus providing phylogenetically relevant information.

Ontophylo: Reconstructing the evolutionary dynamics of phenomes using new ontology‐informed phylogenetic methods

Abstract Reconstructing ancestral states for discrete characters is essential for understanding trait evolution in organisms. However, most existing methods are limited to individual characters and often overlook the hierarchical and interactive nature of traits. Recent advances in phylogenetics now offer the possibility of integrating knowledge from anatomy ontologies to reconstruct multiple discrete character histories. Nonetheless, practical applications that fully harness the potential of these new approaches are still lacking. This paper introduces ontophylo, an R package that extends the PARAMO pipeline to address these limitations. Ontophylo enables the reconstruction of phenotypic entities composed of amalgamated characters, such as anatomical regions or entire phenomes. It offers three new applications: (1) reconstruction of evolutionary rates of amalgamated characters using phylogenetic non‐homogeneous Poisson process (pNHPP) that allows modelling rate variation across tree branches and time; (2) reconstruction of morphospace dynamics; and (3) visualization of evolutionary rates on vector images of organisms. Ontophylo incorporates ontological knowledge to facilitate these applications. Benchmarking confirms the accuracy of pNHPP in estimating character rates under different evolutionary scenarios, and example applications demonstrate the utility of ontophylo in studying morphological evolution in Hymenoptera using simulated data. Ontophylo can be easily integrated with other ontology‐oriented and general‐purpose R packages and offers new opportunities to examine morphological evolution on a phenomic scale using new and legacy data.

Taxonomy, Distribution and Habitat of the Giant Trechus Beetles Endemic to Mt. Choke, Ethiopia (Coleoptera: Carabidae)

The Holarctic ground beetle genus Trechus Clairville, 1806, is highly diverse in the Ethiopian highlands, both in terms of species numbers and morphology. Particularly noteworthy are the extraordinarily large species of the subgenus Abyssinotus Quéinnec and Ollivier, 2021, with a body length up to 8.5 mm, that occur on Mt. Choke in northern Ethiopia. Recent, intensive field work on Mt. Choke resulted in a significantly large number of specimens that are the basis for our taxonomic revision of the species related to the giant species, T. dimorphicus Pawłowski, 2001 and T. gigas Pawłowski, 2001. We describe three new species and one new subspecies and discuss a likely interspecific hybrid that combines morphological character states of representatives of the dimorphicus and gigas subgroups of Abyssinotus. An iconography of males and females as well as photographs of the aedeagi of all the considered species are presented. The distributions of the species are detailed and knowledge of the species-specific habitat preferences is summarized. Based on the distributions and habitat specificity, a threat assessment based on the current land use pattern at Mt. Choke is provided.

Real-time dynamics of vibronic wavepackets within Rydberg and ion-pair states of molecular iodine.

Real-time dynamics of vibrationally and electronically excited I2 molecules has been investigated experimentally using the pump-probe technique. A 2-photon excitation was performed either at 269 nm or 266 nm. An electronic and vibrational wavepacket was built as coherent superposition of a few (269 nm excitation) or many (266 nm excitation) Rydberg states of the and series partly coupled with ion-pair states. The probe operated by ionisation or photodetachement. The energy and angular distribution of the resulting photoelectrons, I+ photocations and I- photoanions were monitored. During the dynamics that is turned on by the pump excitation, the wavepacket splits and explores a variety of electronic states of Rydberg and ion-pair character. The experimental results were complemented by molecular dynamics calculations. This provided invaluable information to identify wavepacket motion along ion-pair potential energy curves.

Delocalisation enables efficient charge generation in organic photovoltaics, even with little to no energetic offset.

Organic photovoltaics (OPVs) are promising candidates for solar-energy conversion, with device efficiencies continuing to increase. However, the precise mechanism of how charges separate in OPVs is not well understood because low dielectric constants produce a strong attraction between the charges, which they must overcome to separate. Separation has been thought to require energetic offsets at donor-acceptor interfaces, but recent materials have enabled efficient charge generation with small offsets, or with none at all in neat materials. Here, we extend delocalised kinetic Monte Carlo (dKMC) to develop a three-dimensional model of charge generation that includes disorder, delocalisation, and polaron formation in every step from photoexcitation to charge separation. Our simulations show that delocalisation dramatically increases charge-generation efficiency, partly by enabling excitons to dissociate in the bulk. Therefore, charge generation can be efficient even in devices with little to no energetic offset, including neat materials. Our findings demonstrate that the underlying quantum-mechanical effect that improves the charge-separation kinetics is faster and longer-distance hops between delocalised states, mediated by hybridised states of exciton and charge-transfer character.

Antonyms in 19th-Century Prose: Quantitative Analysis and Its Idiostylistic Interpretation

This article explores the use of corpora to identify characteristic and individual authorial peculiarities in the use of antonyms in nineteenth-century prose, based on sources such as major antonym dictionaries and corpora for texts by A. P. Chekhov, F. M. Dostoevsky, I. A. Goncharov, I. S. Turgenev, and L. N. Tolstoy. The analytical unit in question is a lexical bigram, i.e. two words in a single phrase, five words apart — left or right. The selection consists of 1933 antonym pairs in context. Comparative statistical analysis has revealed the existence of antonyms used by all the authors in question, a certain “core” of Russian literary antonymy. The most ubiquitous are juxtapositions with semantics such as: alive and dead, good and evil, as well as categories of time, space and emotion. The author identifies textual preconditions for the emergence of antonymous pairs. They are reflections on complex questions of existence, human psychology, interpersonal relationships, social life, etc. Antonyms are often used to describe a person’s appearance, character and psychological state. The article identifies idiostylistic features of the use of antonyms in the works of five Russian writers. A. P. Chekhov’s works are characterised by the use of antonyms to describe emotional and physical qualities of a person. In Dostoevsky, antonymy is prominent in themes of belief and disbelief. I. A. Goncharov points to controversies in the philosophy of life, while in Frigate “Pallada” he appears as a traveller, noting contrasting or complementary qualities of different ethnic groups. Rare examples of authorial use of antonymy in Turgenev’s work support the idiostylistic importance of emotional traits. Antonymy in Tolstoy’s prose is primarily linked to social and family spheres, to the understanding of history, and to the development of the state. The article outlines further directions for research on authorial antonyms based on a wider range of material.

Exploring the Frontier of Password Cracking: Methods, Effectiveness, and Defense Strategies

The manner of attacker's behavior cannot be underestimated; hackers use simple traditional attacks such as brute-force and dictionary attacks as well as sophisticated algorithms including: Markov models, probabilistic context-free grammars (PCFG), and generative adversarial networks (GANs). These are one of among the most advanced approaches which utilize artificial intelligence and machine learning to identify the patterns in passwords, guess them and crack them. Markov models calculate transitions from one character state to another, so they estimate password guesses as a probability which is sampled from the distribution. PCFGs further advance the concept by making use of context-specific inputs for producing the passwords, and as a result it is possible to come up with the candidates who are balanced and have the contextually valid characters. Years ago, the CPA attack was considered the ultimate approach for password cracking. Today, GANs have taken their place, implementing adversarial networks that use them as generators to generate valid password examples. It is evident from the research that abusing users' habits and context during password cracking has been proved that it can lead to a tremendous speed gain of the cracking process. The crackers exploit here patterns in the behavior and environmental features and tailor the cracking strategies. Besides that, recurrent neural networks (RNNs) and convolutional neural networks (CNNs) are considered to be good options in password modeling as well, where the ongoing researches are devoted to the structures of neural network so that the guessing powers of networks can improve. These new approaches have demonstrated an improvement of at least 10-15% over the outdated ones, thus they are credible in forming the password cracking paradigm shift. Thus, for defeating such sophisticated threats, companies should take into account such robust passphrase policies, teach the user about safety of passwords and implementation of rigid access mechanisms. Educating people on cyber threats basics and development of the reasonable cybersecurity culture are the factors that provide the impact reduction of attacks based on users’ behavior and contextual information.

Diverse Motion In-betweening from Sparse Keyframes with Dual Posture Stitching.

In-betweening is a technique for generating transitions given start and target character states. The majority of existing works require multiple (often ≥ 10) frames as input, which are not always available. In addition, they produce results that lack diversity, which may not fulfill artists' requirements. Addressing these gaps, our work deals with a focused yet challenging problem: generating diverse and high-quality transitions given exactly two frames (only the start and target frames). To cope with this challenging scenario, we propose a bi-directional motion generation and stitching scheme which generates forward and backward transitions from the start and target frames with two adversarial autoregressive networks, respectively, and stitches them midway between the start and target frames. In contrast to stitching at the start or target frames, where the ground truth cannot be altered, there is no strict midway ground truth. Thus, our method can capitalize on this flexibility and generate high-quality and diverse transitions simultaneously. Specifically, we employ conditional variational autoencoders (CVAEs) to implement our autoregressive networks and propose a novel stitching loss to stitch the bi-directional generated motions around the midway point.

More than a name: Mid‐Cretaceous amber fossils link crickets and mole crickets (Orthoptera, Ensifera)

AbstractGrylloidea (crickets) and Gryllotalpoidea (mole crickets and ant crickets) are relatively ancient lineages within Orthoptera but their fossil records are not very rich. They are currently considered sister clades within the Gryllidea but with obvious differences in morphology and ecological adaptations. We report a new gryllidean family, †Pseudogryllotalpidae fam. nov. with three new genera and four new species, viz. †Pseudogryllotalpa scalprata gen. et sp. nov., †Unidigitus longialatus gen. et sp. nov., †Petilus zhengi gen. et sp. nov. and †Chunxiania fascia sp. nov. from the mid‐Cretaceous of northern Myanmar (ca. 99 million years ago). Their external and short ovipositors and their modified fossorial forelegs suggest a soil‐inhabiting preference. This new family exhibits a series of ‘intermediate’ character states between Grylloidea and Gryllotalpoidea and seems to be a ‘transitional’ fossil group linking these two superfamilies. This new family was resolved as a sister group of the extant Gryllotalpoidea and provides a new insight into the relationship and evolution of Grylloidea and Gryllotalpoidea.

PSYCHOLOGISM IN THE WORKS OF S. LENZ ("THE OLDEST WOMAN")

Objective. The objective of the article is to identify and characterise the peculiarities of the forms and types of psychologism in the works of S. Lenz translated into Ukrainian (on the basis of “The Oldest Woman” translated by Volodymyr Vasyliuk). Methods. The main scientific results are obtained through a component analysis of the manifestations of the psyche of the characters in the story "The Oldest Woman". The main attention is paid to the psychoanalytic interpretation of emotions, states, feelings of the main character, and the means of expressing the psychological character of the work. Results. In national literary studies, the works of the twentieth-century German writer S. Lenz have not often been the object of attention, although the themes and issues of this writer's works are quite relevant. The problem of the psychologism of S. Lenz's short fiction, his mastery of depicting the psyche and psychology of the characters in his works has been touched upon tangentially in academic works. In “The Oldest Woman”, the organisation of the text plays an important role in achieving psychologicalism. The psychological tension is maintained by an inexplicable dramatic change in the main character's state and moods. For the character of the short story "The Oldest Woman", the decisive feeling is fear. Such a contrast in the tone of the narrative also creates a considerable psychological tension both in the text itself and for the reader. Because of the fear of losing her pension, the woman completely and consciously changes her lifestyle. At first, due to the enthusiastic description at the beginning of the novel, it does not occur to the reader that someone like Birta could be afraid of anything. The author does not reveal the reasons for Birta's frailty until the end of the novel. In addition, the description of the protagonist's states, moods, and feelings is constantly accompanied by a vivid artistic detail, which sometimes reveals the essence of the experience. The narrator in the work helps the reader create a psychological portrait of the characters, revealing their characteristics, thoughts, and aspirations. Particularly valuable are the statements and comments on the characterisation of Birt. The reader's perception and understanding of the character's character and main experiences is based on the narrator's vision of her: he shares his admiration for the physical strength of 92-year-old Birta and creates an image of a strong and unwavering, physically enduring woman, which he supports throughout the text with comments, encouragements to the reader to think, imagine, etc.

Indicating intellectual and emotional states in narrating

The focus of this study is on how children in their retelling of oral stories indicate their understanding of the intentions and feelings of fictional characters. The method used is video documentation of storytelling activities in a preschool, involving 15 children aged 3–5 years and their teachers. The findings clarify how the children indicate the intellectual and emotional states of the fictional characters of stories in three ways: through (i) explicating, (ii) certain forms of gesturing and facial expressions, and (iii) sound symbolism. The educational implications of the findings are discussed in terms of how sound symbolism and gesturing in storytelling are critical to social justice – in allowing children not speaking the majority language to participate in storytelling.

Anatomy of the endocrine pancreas in actinopterygian fishes and its phylogenetic implications

The anatomy and organisation of the endocrine pancreas in ray-finned fishes vary widely. The two main morphoanatomical character states are diffuse versus compact pancreatic tissue. The latter are called Brockmann Bodies (BBs), or principal islets. The present study is the first comprehensive survey on the anatomy of the endocrine pancreas (diffuse versus compact) across 322 actinopterygian species in 39 orders and 135 families based on literature, specimen dissections, and Magnetic Resonance Imaging (MRI). The data obtained show that large endocrine pancreatic islets (BB) have appeared several times in teleost evolution: in some ostariophysian clades and within the Salmoniformes and Neoteleostei. Acanthomorpha (spiny-rayed fishes) is the largest clade of the Neoteleostei. Within this clade, an absence of BBs is only observed in flying fishes (Exocoetidae), parrotfishes (Scarinae), and some of the scarine relatives, the Labridae. The presence of BBs in examined jellynose fish species from the Ateleopodiformes indicates support for its sister-group relationship to the Ctenosquamata (Myctophiformes + Acanthomorpha). More investigations are still needed to corroborate the presence or absence of BBs as a putative synapomorphy for a clade comprising Ateleopodiformes and Ctenosquamata.

The interglenoid tubercle of the atlas is ancestral to lissamphibians.

Lissamphibians, represented today by frogs, salamanders, and caecilians, diverged deep in the tetrapod tree of life. Extensive morphological adaptations to disparate lifestyles have made linking extant lissamphibians to one another and to their extinct relatives difficult and controversial. However, the discovery of a feature on the atlas of the frog Xenopus laevis, may add to the small set of osteological traits that unite lissamphibians. In this study, we combine our observations of atlas development in X. laevis with a deep examination of atlantal interglenoid tubercle (TI) occurrence in fossil taxa. The TI is shown herein to occur transiently on the ossifying atlas of roughly one-third of X. laevis tadpoles but is absent in adults of this species. In ancestral character state estimations (ACSE), within the evolutionary context of lissamphibians as dissorophoid temnospondyls, this feature is found to be ancestrally shared among lissamphibians, its presence is uncertain in stem batrachians, and then the TI is lost in extant caecilians and frogs. However, our data suggests apparent TI loss around the origin of frogs may be explained by its ontogenetically transient nature. The only nonamphibian tetrapods with a TI are "microsaurs," and this similarity is interpreted as one of many convergences that resulted from convergent evolutionary processes that occurred in the evolution of "microsaurs" and lissamphibians. The TI is thus interpreted to be ancestral to lissamphibians as it is found to be present in some form throughout each extant lissamphibian clade's history.