American Museum of Natural History

Phylogenetic analyses of mitochondrial and nuclear data of 31 specimens of Cyphocharax from trans‐Andean rivers support the presence of one lineage of Cyphocharax aspilos in Lago Maracaibo and three cryptic lineages of Cyphocharax magdalenae: (1) Cauca‐Magdalena and Ranchería, (2) León and Atrato, and (3) Chucunaque‐Tuira, Santa María, and Chiriquí basins of Central America. Results suggest that the Serranía del Perijá facilitated Late Miocene cladogenetic events, whereas post‐Isthmian C. magdalenae expansion was enabled by gene flow across the lower Magdalena valley and Central American lowlands. Time‐calibrated phylogenetics indicate that the C. magdalenae colonized lower Central America in the Pliocene (3.7 MYA; Ma), the divergence Atrato‐Magdalena occurred in Late Pliocene (3.0 Ma) and the split Ranchería‐Magdalena during the Middle Pleistocene (1.3 Ma). Updated geographic distribution data support the hypothesis that the Cordillera de Talamanca functions as a barrier to northward expansion of C. magdalenae in Central America.

We report the first field data on the seasonality of natural history events in the viviparous horned lizard species Phrynosoma ditmarsi. Our radiotelemetry tracking of 7 adults (6 females, 1 male) and other encounters allowed us to identify seasonal changes in movement patterns, brumation inactivity, some growth patterns of adults and juveniles, seasonal body temperatures, predation events, feeding patterns, diurnal and nocturnal site selections, mating, and parturition of young. During winter we noted females exhibit inactive brumation in poorly-concealed and mildly protective retreats. They were often in physically exposed sites and two experienced winter predations. Our video recording of a natural mating in mid-November, together with three dramatic female weight losses (mean 42% of total weight) signaling parturition events in July, established fall mating and early summer parturition as the species’ reproductive cycle, with a gestational period of 7-8 months. This clarifies our understanding of their reproductive cycle, one that facilitates rapid newborn growth and maternal resource replenishment during summer monsoonal rains, prior to fall mating by adults before the arrival of low winter activity, reduced growth, and brumation. The following summer, the previous year’s juveniles experience a second monsoonal summer growth period, probably leading to their fall maturation as 15–16 month old reproductive adults.

Genes from ancient families are sometimes involved in the convergent evolutionary origins of similar traits, even across vast phylogenetic distances. Sulfotransferases are an ancient family of enzymes that transfer sulfate from a donor to a wide variety of substrates, including probable roles in some bioluminescence systems. Here, we demonstrate multiple sulfotransferases, highly expressed in light organs of the bioluminescent ostracod Vargula tsujii, transfer sulfate in vitro to the luciferin substrate, vargulin. We find luciferin sulfotransferases (LSTs) of ostracods are not orthologous to known LSTs of fireflies or sea pansies; animals with distinct and convergently evolved bioluminescence systems compared to ostracods. Therefore, distantly related sulfotransferases were independently recruited at least three times, leading to parallel evolution of luciferin metabolism in three highly diverged organisms. Reuse of homologous genes is surprising in these bioluminescence systems because the other components, including luciferins and luciferases, are completely distinct. Whether convergently evolved traits incorporate ancient genes with similar functions or instead use distinct, often newer, genes may be constrained by how many genetic solutions exist for a particular function. When fewer solutions exist, as in genetic sulfation of small molecules, evolution may be more constrained to use the same genes time and again.

Pollinator losses threaten ecosystems and food security, diminishing gene flow and reproductive output for ecological communities and impacting ecosystem services broadly. For four focal families of bees and butterflies, we constructed over 1400 ensemble species distribution models over two time periods for North America. Models indicated disproportionally increased richness in eastern North America over time, with decreases in richness over time in the western US and southern Mexico. To further pinpoint geographic areas of vulnerability, we mapped records of potential pollinator species of conservation concern and found high concentrations of detections in the Great Lakes region, US East Coast, and southern Canada. Finally, we estimated asymptotic diversity indices for genera known to include species that visit flowers and may carry pollen for ecoregions across two time periods. Patterns of generic diversity through time mirrored those of species-level analyses, again indicating a decline in pollinators in the western U.S. Increases in generic diversity were observed in cooler and wetter ecoregions. Overall, changes in pollinator diversity appear to reflect changes in climate, though other factors such as land use change may also explain regional shifts. While statistical methods were employed to account for unequal sampling effort across regions and time, improved monitoring efforts with rigorous sampling designs would provide a deeper understanding of pollinator communities and their responses to ongoing environmental change.

Thank you to the 1396 reviewers who provided 2328 reviews during 2023 to ensure the quality and integrity of JGR‐Oceans manuscripts.

Understanding genetic incompatibilities and genetic introgression between incipient species are major goals in evolutionary biology. Mitochondrial genes evolve rapidly and exist in dense gene networks with coevolved nuclear genes, suggesting that mitochondrial respiration may be particularly susceptible to disruption in hybrid organisms. Mitonuclear interactions have been demonstrated to contribute to hybrid dysfunction between deeply divergent taxa crossed in the laboratory, but there are few empirical examples of mitonuclear interactions between younger lineages that naturally hybridize. Here, we use controlled hybrid crosses and high‐resolution respirometry to provide the first experimental evidence in a bird that inter‐lineage mitonuclear interactions impact mitochondrial aerobic metabolism. Specifically, respiration capacity of the two mitodiscordant backcrosses (with mismatched mitonuclear combinations) differs from one another, although they do not differ significantly from the parental groups or mitoconcordant backcrosses as we would expect of mitonuclear disruptions. In the wild hybrid zone between these subspecies, the mitochondrial cline centre is shifted west of the nuclear cline centre, which is consistent with the direction of our experimental results. Our results therefore demonstrate asymmetric mitonuclear interactions that impact the capacity of cellular mitochondrial respiration and may help to explain the geographic discordance between mitochondrial and nuclear genomes observed in the wild.

A new species of frog-biting midge in the genus Corethrella Coquillett from Death Valley National Park, California, United States of America, is described, based on a single female. The species belongs to the rotunda species group, which are otherwise known to have hyporheic larvae. The species is placed phylogenetically within the group, and a modified portion of a Nearctic key is presented. The rotunda species group now contains 13 species, three of which are in the Nearctic, and the remaining 10 of which are in the Neotropical region.

Insect monitoring is pivotal for assessing biodiversity and informing conservation strategies. This study delves into the complex realm of insect monitoring in the Global South—world developing and least-developed countries as identified by the United Nations Conference on Trade and Development—highlighting challenges and proposing strategic solutions. An analysis of publications from 1990 to 2024 reveals an imbalance in research contributions between the Global North and South, highlighting disparities in entomological research and the scarcity of taxonomic expertise in the Global South. We discuss the socio-economic factors that exacerbate the issues, including funding disparities, challenges in collaboration, infrastructure deficits, information technology obstacles and the impact of local currency devaluation. In addition, we emphasize the crucial role of environmental factors in shaping insect diversity, particularly in tropical regions facing multiple challenges including climate change, urbanization, pollution and various anthropogenic activities. We also stress the need for entomologists to advocate for ecosystem services provided by insects in addressing environmental issues. To enhance monitoring capacity, we propose strategies such as community engagement, outreach programmes and cultural activities to instill biodiversity appreciation. Further, language inclusivity and social media use are emphasized for effective communication. More collaborations with Global North counterparts, particularly in areas of molecular biology and remote sensing, are suggested for technological advancements. In conclusion, advocating for these strategies—global collaborations, a diverse entomological community and the integration of transverse disciplines—aims to address challenges and foster inclusive, sustainable insect monitoring in the Global South, contributing significantly to biodiversity conservation and overall ecosystem health. This article is part of the theme issue ‘Towards a toolkit for global insect biodiversity monitoring’.

Biogeographic studies have generally relied on methods that use a few, large predefined areas, which may overlook fine‐scale patterns. Here we test previous hypotheses about the biogeographic history of a diverse bat clade regarding its association with major Neotropical geological formations, particularly the Antilles, the South American Dry Diagonal, the Andes and the Panamanian land bridge, by applying a recently available method that uses actual distributions instead of predefined areas. We compiled and curated spatially explicit, georeferenced data of 173 bat species (Mammalia: Chiroptera: Noctilionoidea) from the online database Global Biodiversity Information Facility. By taking a previous comprehensive phylogeny as an evolutionary framework, we performed computationally intensive analyses using the Geographically‐explicit Event Model. This method uses the observed species distributions to reconstruct the ancestral areas and biogeographic events at each phylogeny node. We found that sympatric speciation was the most frequently reconstructed event, and involved mainly the Panamanian Isthmus and northern South America (SA), but all sympatry reconstructions were different and specific to each node. Allopatric events were important in the Andes; vicariance caused both west/east and north/south disjunctions that went unnoticed previously. Founder events indicated bidirectional dispersal between the mainland and the Antilles since the Miocene, and across the incomplete Panamanian bridge and the SA Dry Diagonal since the early Pliocene. Overall, we found support for previous hypotheses on the influence of major Neotropical paleogeographic events in the diversification of the group, but additionally revealed multi‐scale patterns that are embedded within the mainland and were previously overlooked. Our results highlight a trans‐isthmian centre of diversification in the biogeographic history of Noctilionoidea including the Panamanian Isthmus and Northern SA.

Despite the recent recognition of ¹⁷O‐excess as a promising new tracer for hydrological processes, our knowledge of the control mechanisms underlying ¹⁷O‐excess in tropical regions remains limited. To understand how microphysical processes during tropical convection affect precipitation isotope ratios, particularly ¹⁷O‐excess, in Singapore, we collected precipitation samples at minute intervals from six rain events associated with cold surges during the Northeast Monsoon seasons and analyzed their triple oxygen isotopes. Our results show that precipitation δ¹⁸O decreases in the convective zones and then gradually increases in the stratiform zones, while d‐excess exhibits an inverse trend. This correlation between δ¹⁸O and d‐excess indicates that rain evaporation plays a crucial role in regulating precipitation isotopes. Moreover, the rain events with a higher upstream rainout amount have lower δ¹⁸O and higher ¹⁷O‐excess values, suggesting that precipitation δ¹⁸O and ¹⁷O‐excess likely reflect the integrated upstream convective activity. Microphysical processes associated with upstream convection, such as rain evaporation and vapor recycling, are potential mechanisms that increase ¹⁷O‐excess values along moisture transport pathways for a rain event, and hence, undermine the effectiveness of ¹⁷O‐excess as a tracer of moisture source humidity. Contrary to the negative correlation observed in monthly precipitation, there is generally a positive correlation between d‐excess and ¹⁷O‐excess at the event scale. However, this correlation weakens as convective rain intensifies, suggesting that stronger convection can attenuate the positive correlation between d‐excess and ¹⁷O‐excess. Therefore, it is crucial to consider how tropical convection alters ¹⁷O‐excess when utilizing this tracer to interpret atmospheric dynamics and hydrological processes.

Bats appear in the fossil record on multiple continents during the early Eocene. More than seventy Eocene bat species have been named to date, including stem bats, probable members of crown families, and others of uncertain affinity. Most phylogenetic analyses of Eocene bat relationships have focused on the handful of taxa known from nearly complete skeletal material, whereas the taxonomic relationships of more incomplete fossils have been based largely on phenetic similarities. Here we evaluate the evolutionary relationships of over 60 species of Eocene bats—including many taxa known only from fragmentary craniodental remains—in an explicitly phylogenetic context. Our analysis is based on nearly 700 morphological characters scored in 82 taxa, including 20 extant species representing all living bat families other than Pteropodidae. We found that phylogenetic relationships of Eocene bats are more complex than previously thought. Numerous families (e.g., †Archaeonycteridae, †Mixopterygidae, †Palaeochiropterygidae) and genera (e.g., †Archaeonycteris, †Icaronycteris, †Carcinipteryx) were found to be non-monophyletic as previously recognized, requiring adjustments to chiropteran taxonomy. Four major clades of stem bats were recovered in our analyses. †Microchiropteryx folieae (~ 54 Ma, India) was recovered as the earliest crown bat, occurring as the most basal lineage of Vespertilionoidea, whereas many putative crown bats were recovered among stem Chiroptera. †Tachypteron franzeni was found to be a crown bat in our analyses, as in previous studies, but it was recovered unexpectedly as a stem miniopterid. The phylogenetic relationships presented here represent the most comprehensive analysis of Eocene bat relationships completed to date, substantially improving our understanding of the position of many fossil taxa within Chiroptera and providing a foundation for future analyses of bat evolution.

It is a pleasure to be invited to contribute to the celebration of the publication of “punctuated equilibria” (“punk eek”) 50 years ago—the canonical version I did with Steve Gould (Eldredge and Gould 1972) at the behest of Tom Schopf for his visionary project to inject more thought, more interpretation and theory, into the working lives of paleontologists.

The Cretaceous-Paleogene (K-Pg) mass extinction precipitated one of the most profound restructurings of biodiversity in recent geological history. Despite the extinction of many iconic groups, particularly the non-avian dinosaurs, there is emerging evidence that previously overlooked taxa experienced stark morphological and evolutionary stasis. In this study, we report both adult and larva of beetles of the genus Loricera preserved in mid-Cretaceous Kachin amber (Figure 1), which display striking similarity to extant congeners, indicating a stasis of their specialized feeding behavior persisting at least 100 million years.

Environmental DNA (eDNA) workflows contain many familiar molecular-lab techniques, but also employ several unique methodologies. When working with eDNA, it is essential to avoid contamination from the point of collection through preservation and select a meaningful negative control. As eDNA can be obtained from a variety of samples and habitats (e.g., soil, water, air, or tissue), protocols will vary depending on usage. Samples may require additional steps to dilute, block, or remove inhibitors or physically break up samples or filters. Thereafter, standard DNA isolation techniques (kit-based or phenol:chloroform:isoamyl [PCI]) are employed. Once DNA is extracted, it is typically quantified using a fluorometer. Yields vary greatly, but are important to know prior to amplification of the gene(s) of interest. Long-term storage of both the sampled material and the extracted DNA is encouraged, as it provides a backup for spilled/contaminated samples, lost data, reanalysis, and future studies using newer technology. Storage in a freezer is often ideal; however, some storage buffers (e.g., Longmires) require that filters or swabs are kept at room temperature to prevent precipitation of buffer-related solutes. These baseline methods for eDNA isolation, validation, and preservation are detailed in this protocol chapter. In addition, we outline a cost-effective, homebrew extraction protocol optimized to extract eDNA.

This chapter provides a reference glossary for the protocols in this volume. We have chosen only the very basic terms in the DNA barcode lexicon to include, and provide clear and concise definitions of these terms. We hope the reader finds this glossary useful.

This chapter discusses methods for incorporating DNA barcode information into formal taxonomic descriptions. We first review what a formal description entails and then discuss previous attempts to incorporate barcode information into taxonomic descriptions. Several computer programs are listed that extract diagnostics from DNA barcode data. Finally, we examine a test case (Astraptes taxonomy).

A new genus and species of halictine bees (Halictinae: Halictini: Mexalictina) is described and figured from a mid-elevation forest in northwestern Costa Rica. Meliamelitta vulcanus gen. and sp. n. is allied to Mexalictus Eickwort but differs in the structure of the labral basal elevation, the obtuse epistomal sulcus, the elongate mandibles, the pectinate inner metatibial spur, the unique pterostigma, and the sculpturing of the basal area of the propodeum, among other features. A key is appended to the genera and subgenera of Mesoamerican, Central American, and Caribbean Halictinae to facilitate the recognition of the genus.