Observation of suppressed viscosity in the normal state of 3He due to superfluid fluctuations.

Evidence of fluctuations in transport have long been predicted in 3He. They are expected to contribute only within 100µK of Tc and play a vital role in the theoretical modeling of ordering; they encode details about the Fermi liquid parameters, pairing symmetry, and scattering phase shifts. It is expected that they will be of crucial importance for transport probes of the topologically nontrivial features of superfluid 3He under strong confinement. Here we characterize the temperature and pressure dependence of the fluctuation signature, by monitoring the quality factor of a quartz tuning fork oscillator. We have observed a fluctuation-driven reduction in the viscosity of bulk 3He, finding data collapse consistent with the predicted theoretical behavior.

Unveiling underestimated species diversity within the Central American Coralsnake, a medically important complex of venomous taxa.

Coralsnakes of the genus Micrurus are a diverse group of venomous snakes ranging from the southern United States to southern South America. Much uncertainty remains over the genus diversity, and understanding Micrurus systematics is of medical importance. In particular, the widespread Micrurus nigrocinctus spans from Mexico throughout Central America and into Colombia, with a number of described subspecies. This study provides new insights into the phylogenetic relationships within M. nigrocinctus by examining sequence data from a broad sampling of specimens from Mexico, Guatemala, Honduras, Nicaragua, Costa Rica, and Panama. The recovered phylogenetic relationships suggest that M. nigrocinctus is a species complex originating in the Pliocene and composed of at least three distinct species-level lineages. In addition, recovery of highly divergent clades supports the elevation of some currently recognized subspecies to the full species rank while others may require synonymization.

A new species of Dipsas (Serpentes, Dipsadidae) from central Panama.

A new species of Dipsas Laurenti, 1768, from Central Panama is described based on molecular analyses, hemipenial morphology, and external characters. This is the sixth species of Dipsas to be described for the country; the snake has been suspected to exist since 1977 and has not been thoroughly studied until now. Additionally, morphological comparations including scale counts are done with other species within the genus, and the current geographic distribution of Dipsastemporalis (Werner, 1909), the sister species, is updated. Finally, a key to the species of Dipsas currently known from Middle America is presented.

ResumenDescribimos una nueva especies de Dipsas Laurenti, 1768 de la región central de Panamá en base a análisis moleculares, morfología hemipenial y caracteres de morfología externa. Esta es la sexta especie del género Dipsas descrita para el país. Se sospechaba su existencia desde 1977 pero no había sido estudiada exhaustivamente hasta ahora. Adicionalmente, presentamos comparaciones morfológicas (incluyendo lepidosis) con otras especies del género y actualizamos la distribución geográfica de su especie hermana Dipsastemporalis (Werner, 1909). Finalmente, presentamos una clave para las especies de Dipsas distribuidas en Centroamérica.

Where and with whom does a brief social-belonging intervention promote progress in college?

A promising way to mitigate inequality is by addressing students' worries about belonging. But where and with whom is this social-belonging intervention effective? Here we report a team-science randomized controlled experiment with 26,911 students at 22 diverse institutions. Results showed that the social-belonging intervention, administered online before college (in under 30 minutes), increased the rate at which students completed the first year as full-time students, especially among students in groups that had historically progressed at lower rates. The college context also mattered: The intervention was effective only when students' groups were afforded opportunities to belong. This study develops methods for understanding how student identities and contexts interact with interventions. It also shows that a low-cost, scalable intervention generalizes its effects to 749 4-year institutions in the United States.

Evaluation of the "rethink stress" mindset intervention: A metacognitive approach to changing mindsets.

Experimental research has demonstrated that a stress-is-enhancing mindset can be induced and can improve outcomes by presenting information on the enhancing nature of stress. However, experimental evidence, media portrayals, and personal experience about the debilitating nature of stress may challenge this mindset. Thus, the traditional approach of focusing on the more "desired" mindset without arming participants against encounters with the less desired mindsets may not be sustainable in the face of conflicting information. How might this limitation be resolved? Here, we present three randomized-controlled interventions that test the efficacy of a "metacognitive approach." In this approach, participants are given more balanced information about the nature of stress along with metacognitive information on the power of their mindsets aimed at empowering them to choose a more adaptive mindset even in the face of conflicting information. In Experiment 1, employees of a large finance company randomized to the metacognitive mindset intervention reported greater increases in stress-is-enhancing mindsets and greater improvements in self-reported measures of physical health symptoms and interpersonal-skill work performance 4 weeks later compared to a waitlist control. Experiment 2, adapted to be distributed electronically via multimedia modules, replicates the effects on stress mindset and symptoms. Experiment 3 compares the metacognitive stress mindset intervention with a more traditional stress mindset manipulation. The metacognitive approach led to greater initial increases in a stress-is-enhancing mindset relative to the traditional intervention, and these increases were sustained after exposure to contradictory information. Taken together, these results provide support for a metacognitive approach to mindset change. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A new species of Sceloporus of the torquatus group (Reptilia: Phrynosomatidae) from West Mexico.

We describe Sceloporus huichol sp. nov., a new species of spiny lizard of the genus Sceloporus, that is found in the mountainous regions of Jalisco and Nayarit in western Mexico. The new species belongs to the torquatus species group and has previously been confused with Sceloporus melanogaster, from which it differs by its smaller size, head color and nuchal collar. Additionally, Sceloporus huichol sp. nov. is different from the rest of its congeners by relevant genetic and morphologicall data. Despite having a complete nuchal collar, characteristic of Sceloporus torquatus, S. huichol sp. nov. is more closely related phylogenetically to S. melanogaster. Recognition of this new species brings the number of species in the torquatus group to nine.

Phylogeographic inference of Sumatran ranids bearing gastromyzophorous tadpoles with regard to the Pleistocene drainage systems of Sundaland.

Rivers are known to act as biogeographic barriers in several strictly terrestrial taxa, while possibly serving as conduits of dispersal for freshwater-tolerant or -dependent species. However, the influence of river systems on genetic diversity depends on taxa-specific life history traits as well as other geographic factors. In amphibians, several studies have demonstrated that river systems have only minor influence on their divergence. Here, we assess the role of the paleodrainage systems of the Sunda region (with a focus on the island of Sumatra) in shaping the evolutionary history of two genera of frogs (Sumaterana and Wijayarana) whose tadpoles are highly dependent on cascading stream habitats. Our phylogenetic results show no clear association between the genetic diversification patterns of both anurans genera and the existence of paleodrainage systems. Time-calibrated phylogenies and biogeographical models suggest that these frogs colonized Sumatra and diversified on the island before the occurrence of the Pleistocene drainage systems. Both genera demonstrate phylogenetic structuring along a north-south geographic axis, the temporal dynamics of which coincide with the geological chronology of proto Sumatran and -Javan volcanic islands. Our results also highlight the chronic underestimation of Sumatran biodiversity and call for more intense sampling efforts on the island.

A new species of Oreosaurus (Squamata: Gymnophthalmidae) from the Turimiquire Massif, northeastern Venezuela.

We describe a new species of gymnophthalmid lizard, Oreosaurus bisbali sp. nov., from the Turimiquire Massif in northeastern Venezuela. It is one of three reptile species known to be endemic to the region and the fifth species of Oreosaurus from Venezuela. It can be distinguished from all congeners by a combination of rectangular dorsal scales at midbody, having two scales separating femoral pores medially, and lacking a nasoloreal suture. The new species is likely to be restricted in distribution to the highlands of the Turimiquire Massif, which have been significantly degraded by agriculture.

Hidden in the plain sight: a new species of Rhabdophis (Serpentes: Natricinae) from the Rhabdophis himalayanus complex.

A new species of natricine snake of the genus Rhabdophis is described from Northeast India. Morphologically the new species is similar to Rhabdophis himalayanus but it can be distinguished from it by lacking a nuchal groove and nuchal glands, being relatively smaller, and having a distinct neck, ventral, and subcaudal coloration. In overall coloration it resembles R. chrysargos, from which it is distinguished by several aspects of its morphology and genetic differences. The discovery of Rhabdophis bindi sp. nov. reveals that forested regions in the northeastern part of India needs further biological exploration.

A tiny new species of Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae) from Belitung Island and Southeastern Sumatra, Indonesia.

A tiny new species of narrow-mouthed frog of the genus Microhyla is described from the island of Belitung and southeastern Sumatra, Indonesia. The most distinctive feature of the new frog is its diminutive adult size, snout-vent length ranging only from 12.3 to 15.8 mm in adult males. Phylogenetic analyses based a fragment of the mitochondrial 16S rRNA gene, along with detailed morphological and acoustic comparison differentiate the new taxon from all known congeners. The new species, formally described as Microhyla sriwijaya sp. nov., is a member of the M. achatina species group and the sister taxon to M. orientalis. It is diagnosable from other congeners by a combination of characters: (1) smaller male snout-vent size 16 mm; (2) snout obtusely rounded in dorsal view; (3) absence of mid-dorsal line and skin fold; (4) first finger reduced (finger I length less than half of finger II length); (5) dorsum with a prominent dark median mark extending posteriorly, narrow anteriorly near the level of the shoulder and expanding dorsolaterally up to the vent; margins of the dorsal marking concave with broad reddish-brown or orange colouration on either side; (6) foot webbing rudimentary, reaching just up to the first subarticular tubercle on all toes; (7) dorsal skin with prominent tubercles, especially in life; (8) tibiotarsal articulation of adpressed limb reaching beyond the snout tip; and (9) males produce a single type of call with pulsatile temporal structure, calls of relatively short duration ranging between 31.862.8 s, with two to three pulses delivered at a rate ranging between 32.236.0 pulses per second, and the mean overall dominant frequency of 4.3 kHz. The uncorrected pairwise genetic distances between Microhyla sriwijaya sp. nov. and all other known congeners are > 3.8% for the studied 16S gene fragment. The new species was discovered from wayside rural areas with oil palm plantations at four localities in the small island of Belitung (type locality), and from coffee plantation and secondary forest at Lampung in southeastern Sumatra. It is not known from any protected area and appears to be threatened due to tin mining activity, intensive logging, oil palm, and other commonly practiced agriculture activities.

Two new species of Megophrys Kuhl and Van Hasselt (Amphibia: Megophryidae) from Sumatra, Indonesia.

We evaluated the taxonomic status of the genus Megophrys in Sumatra using molecular and morphological data. Mitochondrial phylogenetic inference and morphological data revealed two undescribed species, one in southern SumatraM. selatanensis sp. nov. and one in northern SumatraM. acehensis sp. nov. We also detected a potential cryptic species within M. parallela, but refrain from describing this lineage here due to insufficient data. Genetic variation within Sumatran Megophrys is highly structured and will require additional geographic sampling to understand the interplay between geography and genetics in Sumatran Megophrys.

Phylogeny and biogeography of Sumatra´s cloud forest lizards of the genus Dendragama and status of Acanthosaura schneideri.

Lizards of the genus Dendragama are endemic to the highland cloud forests of Sumatra's Barisan Mountain Range in western Indonesia, and recent studies have uncovered widespread diversity within the genus. Here, a suite of morphological characters and mitochondrial DNA are used to compare three geographically isolated populations of D. boulengeri from (1) Mount Kerinci in Jambi province, (2) Mount Marapi of west Sumatra, and (3) the Karo Highlands of north Sumatra. Additional phylogeographic analyses with two recently described sister species, D. australis and D. dioidema were conducted. Five genetically distinct clades of Dendragama, all distributed allopatrically of one another were identified and some are suspected to inhabit small distributions. Morphological and genetic data confirm the Karo Highlands population D. schneideri (previously Acanthosaura schneideri Ahl, 1926) should be revalidated from the synonymy of D. boulengeri. Dendragama schneideri is endemic to montane forests of the Karo Highlands surrounding Lake Toba in Sumatra Utara province. Pairwise genetic distances of 6-11% separate D. schneideri from congeners. Two distinct clades of D. boulengeri from Mount Kerinci and Mount Marapi were identified, which are 5.0% genetically distant from one another. Using morphological characters, we provide the first key for distinguishing between species of Dendragama. Based on biogeographic patterns and levels of genetic variation it is suspected that at least 18 other isolated cloud forest locations may hold new species or divergent populations of Dendragama but lack survey work. Collectively, these comparisons among populations of montane lizards further elucidate the complex biogeographic history of Sumatra's montane forest species and the first phylogeny of the genus Dendragama.

Taxonomic evaluation of two similar bent-toed geckos Squamata: Gekkonidae: Cyrtodactylus Gray, 1827) from East Java, Indonesia.

The bent-toed geckos of the genus Cyrtodactylus are the most speciose land vertebrates of Southeast Asia (about 300 species so far) and new species continue to be recognized at a rapid rate. Within the last decade three new species were described from Java, Indonesia, C. semiadii, C. petani, and C. klakahensis. The latter two are very similar, except for differences in the precloacal depression in adult males. These two species have relatively close type localities, separated from each other by only about 50 km, and with similar habitat type and elevation. Our study aimed to evaluate the taxonomic status of C. klakahensis and C. petani using both morphological and genetic evidence. These two species are genetically similar, with a genetic divergence of only 1.5 to 1.6%. This divergence is well below the level of typically characterizes sister species of Cyrtodactylus (approximately 4% in the mitochondrial ND2 gene), and is more in line with population variation due to geographic distance. Further examination of specimens, from both type localities, showed no diagnostic morphological characters between the two species. Thus, we conclude that C. klakahensis and C. petani are conspecific, and following article 23 of the ICZN, C. klakahensis is herein considered a junior synonym of C. petani.

Possible osteosarcoma reported from a new world elapid snake and review of reptilian bony tumors.

Cancer chiefly occurs in vertebrates. Rare in amphibians, and perhaps common in reptiles, various neoplasms and malignant cancers have been reported with erratic frequency by museums, paleontologists, veterinarians, and pet hobbyists. Unsurprisingly, most herpetofaunal diversity has never been systematically surveyed for the presence of neoplasms owing to the extreme rarity or obscurity of many species. Museum collections can fill these gaps in knowledge, especially when researchers use non-destructive techniques. In this study, we used X-ray computed tomography (CT) to discover and characterize a possible osteosarcoma of the spine in a rare South American coralsnake, Micrurus ancoralis. Two spinal vertebrae were completely fused and adjacent vertebrae showed evidence of corruption. The fused vertebrae contained a hollow inner network thought to be vascular tissue. We also review previous reports of neoplasms in the Elapidae and all bony neoplasms in non-avian reptiles. The rarely reported technique of X-ray CT for tumor discovery could greatly improve our understanding of the species diversity and perhaps underlying causes of neoplasia.

Impacts of the Toba eruption and montane forest expansion on diversification in Sumatran parachuting frogs (Rhacophorus).

Catastrophic events, such as volcanic eruptions, can have profound impacts on the demographic histories of resident taxa. Due to its presumed effect on biodiversity, the Pleistocene eruption of super-volcano Toba has received abundant attention. We test the effects of the Toba eruption on the diversification, genetic diversity, and demography of three co-distributed species of parachuting frogs (Genus Rhacophorus) on Sumatra. We generate target-capture data (~950 loci and ~440,000 bp) for three species of parachuting frogs and use these data paired with previously generated double digest restriction-site associated DNA (ddRADseq) data to estimate population structure and genetic diversity, to test for population size changes using demographic modelling, and to estimate the temporal clustering of size change events using a full-likelihood Bayesian method. We find that populations around Toba exhibit reduced genetic diversity compared with southern populations, and that northern populations exhibit a shift in effective population size around the time of the eruption (~80 kya). However, we infer a stronger signal of expansion in southern populations around ~400 kya, and at least two of the northern populations may have also expanded at this time. Taken together, these findings suggest that the Toba eruption precipitated population declines in northern populations, but that the demographic history of these three species was also strongly impacted by mid-Pleistocene forest expansion during glacial periods. We propose local rather than regional effects of the Toba eruption, and emphasize the dynamic nature of diversification on the Sunda Shelf.

Phylogeography of montane dragons could shed light on the history of forests and diversification processes on Sumatra.

Biogeographical evidence, both, for and against the "regional endemism paradigm" hypothesis has been uncovered across the Greater Sunda Region (Sundaland) of Southeast Asia. Additionally, there are competing hypotheses regarding how Pleistocene forests may have impacted biological patterns and processes in Sumatra. Using montane agamid lizards from Sumatra, we derived and analyzed a phylogenetic dataset, genetic divergence estimates, and contemporary distributional patterns among species. We tested whether (1) Sumatra's highland Draconinae diversification fits the regional endemism paradigm hypothesis and (2) Draconinae phylogeography provides biological evidence for Pleistocene forest extent at various points in history. Our results suggest in situ diversification was the main driver behind montane Draconinae lizard diversification in Sumatra, rejecting the "regional endemism paradigm". Contemporary distribution of endemic species and their genetic relationships may potentially provide biologicalevidence for determining more precise elevational lower limits of montane forests during the Pleistocene epoch. Our data suggests montane forests did not retreat more than 700-750 m during glacial maxima because lower retreating forests would have become interconnected, allowing for widespread dispersal, exchange of gene flow and sympatric distributions contemporarily. To the contrary, our divergence estimates show that cloud forest dragons have been isolated for millions of years, suggesting there may have been a continuous disconnect between some areas, predating the Pleistocene. There may also be other ecological and evolutionary factors that impacted Draconinae distributions, such as competition, making this an excellent system for testing questions regarding montane biogeography. Additionally, we provide the first phylogeny for a wide range of Sundaland agamid species and identify some biogeographic pressures that may have triggered montane Draconinae diversification in Sumatra.

Genome-wide SNPs clarify lineage diversity confused by coloration in coralsnakes of the Micrurus diastema species complex (Serpentes: Elapidae).

New world coralsnakes of the genus Micrurus are a diverse radiation of highly venomous and brightly colored snakes that range from North Carolina to Argentina. Species in this group have played central roles in developing and testing hypotheses about the evolution of mimicry and aposematism. Despite their diversity and prominence as model systems, surprisingly little is known about species boundaries and phylogenetic relationships within Micrurus, which has substantially hindered meaningful analyses of their evolutionary history. Here we use mitochondrial genes together with thousands of nuclear genomic loci obtained via ddRADseq to study the phylogenetic relationships and population genomics of a subclade of the genus Micrurus: The M. diastema species complex. Our results indicate that prior species and species-group inferences based on morphology and color pattern have grossly misguided taxonomy, and that the M. diastema complex is not monophyletic. Based on our analyses of molecular data, we infer the phylogenetic relationships among species and populations, and provide a revised taxonomy for the group. Two non-sister species-complexes with similar color patterns are recognized, the M. distans and the M. diastema complexes, the first being basal to the monadal Micrurus and the second encompassing most North American monadal taxa. We examined all 13 species, and their respective subspecies, for a total of 24 recognized taxa in the M. diastema species complex. Our analyses suggest a reduction to 10 species, with no subspecific designations warranted, to be a more likely estimate of species diversity, namely, M. apiatus, M. browni, M. diastema, M. distans, M. ephippifer, M. fulvius, M. michoacanensis, M. oliveri, M. tener, and one undescribed species.

The roles of vicariance and dispersal in the differentiation of two species of the Rhinella marina species complex.

The high levels of Neotropical biodiversity are commonly associated with the intense Neogene-Quaternary geological events and climate dynamics. Here, we investigate the evolutionary history of two species of Neotropical closely related amphibians (R. horribilis and R. marina). We combine published data with new mitochondrial DNA sequences and multiple nuclear markers, including 12 microsatellites. The phylogenetic analyses showed support for grouping the samples in two main clades; R. horribilis (Central America and Mexico) and R. marina (South America east of the Andes). However, the phylogenetic inferences also show an evident mito-nuclear discordance. We use Approximate Bayesian Computation (ABC) to test the role of different events in the diversification between the two groups recovered. We found that both species were affected primarily by a recent Pleistocene divergence, which was similar to the divergence estimate revealed by the Isolation-with-Migration model, under persistent bidirectional gene flow through time. We provide the first evidence that R. horribilis is differentiated from the South American R. marina at the nuclear level supporting the taxonomic status of R. horribilis, which has been controversial for more than a century.

New species, diversity, systematics, and conservation assessment of the Puppet Toads of Sumatra (Anura: Bufonidae: Sigalegalephrynus).

Using a combination of morphological and molecular data we recognize three new species of Puppet Toad, Sigalegalephrynus Smart, Sarker, Arifin, Harvey, Sidik, Hamidy, Kurniawan Smith, a recently described genus endemic to the highland forests of Sumatra, Indonesia. Phylogenetic analysis of mitochondrial DNA sequences recovered a monophyletic relationship among all Puppet Toads, with two distinct evolutionary clades, a northern and a southern. The northern clade includes Sigalegalephrynus gayoluesensis sp. nov., and S. burnitelongensis sp. nov., and the southern clade includes S. harveyi sp. nov., S. mandailinguensis, and S. minangkabauensis. With the discovery of these three new species, Sigalegalephrynus contains more endemic species than any other genus of toad in Indonesia. We used maximum entropy, implemented in MaxEnt, to identify suitable habitats and occurrence probability of additional undescribed new species from the island. The most important predictors of Sigalegalephrynus distribution were elevation (64.5%) and land cover (7.11%). Based on the probability of presence, it is likely that there are many more species of the genus awaiting discovery in Sumatra. Our analysis, based on IUCN Red List of Threatened Species category and criteria, shows that all of the five species of Sigalegalephrynus are in great risk of extinction and should be placed into the Endangered (EN) category of IUCN Red List.

Rediscovery of Micryletta inornata (Boulenger, 1890) from Sumatra: redescription, molecular identity, and taxonomic implications.

Micryletta inornata (Boulenger 1890), the type species of the genus Micryletta, was originally described from the island of Sumatra in Indonesia. Subsequently, this species has been widely reported from Sundaland (Sumatra and Malay Peninsula), Indo-China, Northeast India and South Andaman, up to southern China and Taiwan. However, since the original description there has been no further report of this species from the type locality or the island. During a herpetofaunal survey in Sumatra, several specimens that are morphologically concordant with the original description and the syntypes of M. inornata were found, and thus the species was rediscovered after 125 years. Here, we provide a redescription of the species based on the freshly collected specimens, along with a detailed morphological and molecular comparison with known congeners. Further, using molecular data from the mitochondrial 16S rRNA gene, our study recovered the Sumatran M. inornata as a phylogenetically distinct lineage from all other populations previously referred to this species. This confirms that all known Micryletta 'inornata' populations from regions outside Sumatra constitute several other lineages representing either new species or previously available names currently considered as synonyms, consequently requiring taxonomic validation in the future.