The complete mitochondrial genome of Voluta musica, the type species of the type genus of the family Volutidae, was determined using Illumina sequencing and found to be a double stranded circular molecule 15,306 base pairs in length with a GC content of 37.2%. It contains 13 protein-coding genes, 2 ribosomal RNA genes, and 22 tRNA genes with the same gene order and strand orientation as in most neogastropods, including all Volutidae, for which mitogenomes have been determined. The potential origin of replication is located in a 62-bp non-coding region between tRNA-Phe and the gene for COX3. Phylogenetic analyses using maximum likelihood and Bayesian inference with nucleotide sequences of all protein coding and ribosomal genes show Voluta musica to be most closely related to Fulgoraria rupestris, support the monophyly of Volutidae, and contradict the inclusion of Cancellariidae within Volutoidea.

As thermal stress and disease outbreaks decimate coral reefs throughout the tropics, there is growing evidence that higher latitude marine environments may provide crucial refuges for many at-risk, temperature-sensitive coral species. However, our understanding of how coral populations expand into new areas and sustain themselves over time is constrained by the limited scope of modern observations. Here, we provide geological insights into coral range expansions by reconstructing the composition of a Late Holocene-aged subfossil coral death assemblage on the southeast Florida reef tract and comparing it to modern reefs throughout the region. Our findings show that the Late Holocene coral assemblages were dominated by now critically endangered Acropora species between ~3500 and 1800 years before present, mirroring classic zonation patterns characteristic of healthy pre-1970s Caribbean reefs. In contrast, the modern reefs off southeast Florida are becoming increasingly dominated by stress-tolerant species like Porites astreoides and Siderastrea siderea despite modest expansions of Acropora cervicornis over the past several decades. Our results suggest that ongoing anthropogenic stressors, not present during the Late Holocene, are likely limiting the ability of modern higher latitude reefs in Florida to function as long-term climate refugia.

In recent years, coral populations in the western Atlantic have undergone widespread declines from climate change, anthropogenic stressors, and infectious disease outbreaks. The pillar coral, Dendrogyra cylindrus , has been one of the most affected species, prompting its listing as threatened under the United States Endangered Species Act in 2014 and critically endangered under the IUCN Red List in 2022. However, due to its natural rarity, it is particularly difficult to study using conventional long-term monitoring studies or less common paleontological investigations. Here, we document for the first time, the multi-century persistence of D. cylindrus on high-latitude nearshore reefs off southeast Florida during the late Holocene. Using high-precision uranium–thorium (U-Th) dating, we constrain the ages of well-preserved subfossil D. cylindrus colonies recovered from newly described coral death assemblages. We also describe specific morphological characteristics and taphonomic indicators reflecting their unique depositional environment. Our findings demonstrate long-term persistence of D. cylindrus in southeast Florida, despite geographical isolation and historical rarity in the region.

Live and fresh dead specimens of Naria turdus, a species with a native range in the Red Sea and the western Indian Ocean, were found in shallow water off the island of Aruba in the south-western Atlantic. The most plausible pathways for the invasion of the species are considered to be the transport of larvae in ballast waters of a cargo ship, or attachment of the egg capsules to the cargo ship hull. A combination of juvenile, young adult, and fully mature specimens was observed, suggesting a new, well-established, and possibly breeding population of N. turdus in the western Atlantic.

The Cretaceous-Paleogene (KPg) boundary is demarked by two critical and intimately linked events: a global-scale impact caused by a massive extraterrestrial body, and a resultant catastrophic planet-wide mass-extinction, with pivotal long-term consequences for life on Earth. The site of impact has been identified as the ~180 km wide Chicxulub crater complex [Yucatan peninsula, Mexico] based on strong geochemical, sedimentological, and temporal evidence. However, the impactor, which was obliterated on contact during the cratering process, has eluded identification. Previous studies struggled to identify the projectile based on scant geochemical and isotopic traces admixed with the ejecta and melt-rock, plus a single heavily altered microscopic fragment possibly from the impactor. While those efforts helped to rule out some potential sources and narrowed down the best potential candidates to a CM, CR, or CO carbonaceous chondrite, the data was insufficient to provide an incontrovertible diagnosis, and the identity of the Chicxulub projectile remained a critical missing detail. Here we describe new, exceptionally-preserved fragments of cosmic origin that were directly associated with Chicxulub impact ejecta from a temporally constrained KPg boundary site in North Dakota (U.S.A.). The fragments occur as inclusions within unaltered glassy ejecta spherules, which likely protected them against chemical and physical degradation, leading to their marked preservation. The spherules themselves were also uniquely preserved in amber, which inhibited their usual breakdown to smectitic clay. Geochemical examination of the inclusions were undertaken using electron microprobe, laser-ablation inductively-coupled-plasma-mass-spectroscopy, and synchrotron X-ray techniques. Results provide multiple lines of evidence that support a cosmic origin and chemistry indicative of a CM subtype carbonaceous chondrite, offering new support of prior hypotheses. The data is also in agreement with projectile residues from the Chicxulub impact fallout. In addition to its utility in reconstructing the dynamics of the Chicxulub event, this data helps provide extra dimension to our understanding of major impact processes and their effects on Earth.

<p>Dinosaurs and pterosaurs, critical components of late Mesozoic terrestrial biomes, have thus far never been reported in-situ from deposits immediately below the Cretaceous-Paleogene (KPg) boundary. Strata from the KPg boundary preserve worldwide evidence of a massive cosmic impact that resulted in grave consequences for Earth’s biota, triggering a rapid global mass extinction that ultimately claimed ~75% of species. While trends in long-term biotic effects are well-documented, little is known about the fate of biota coeval with the impact because well-preserved fossil evidence is lacking for that brief time interval. Here we report the first-known occurrences of in-situ dinosaur and pterosaur remains coincident with the KPg boundary, providing a vantage point that is closer in temporal proximity to the Chicxulub impact than any prior known records for these clades. The fossils, preserved in a Chicxulub impact-triggered surge deposit and mass-death assemblage in the Hell Creek Formation, U.S.A., consist of a well-developed semi-articulated prenatal pterosaur in ovum and partially articulated remains of a subadult ornithischian dinosaur (Family Thescelosauridae). Examination via synchrotron rapid scanning X-ray fluorescence (SRS-XRF), scanning electron microscopy (SEM), and traditional light microscopy revealed extensive preservation of soft tissue consisting of distinct signatures of organic residues as well as three-dimensional structure. The pterosaur embryo, which comprises the first known from the Late Cretaceous and the only example thus far from North America, contributes information pivotal to understanding the prenatal development and early ontogeny of these animals from a time interval for which no such data exists. The ornithischian (c.f. <em>Thescelosaurus</em> sp.) dinosaur, which includes a remarkably complete articulated hind limb enclosed within three-dimensional lithified tubercular skin envelope, provides important data regarding the osseous and soft-tissue anatomy of the Thescelosauridae. In addition to contributing invaluable new anatomical and physiological insights, these specimens constitute the first conclusive evidence of the direct participation of pterosaurs and dinosaurs in the terminal-Cretaceous extinction event.</p>

The Holocene reefs off southeast Florida provide unique insights into the biogeographical and ecological response of western Atlantic coral reefs to past climate change that can be used to evaluate future climate impacts. However, previous studies have focused on millennial-scale change during the stable mid-Holocene, making it difficult to make inferences about the impact of shorter-term variability that is relevant to modern climate warming. Using uranium-series dating of newly discovered subfossil coral rubble deposits, we establish a new high-resolution record of coral community development off southeast Florida during a period of variable climate in the late Holocene. Our results indicate that coral communities dominated by reef-building Acropora palmata and Orbicella spp. persisted in the nearshore environments off southeast Florida ~75 km north of their primary historical ranges between ~3500 and 1800 years before present. This timing coincides with regional warming at the northern extent of the Atlantic Warm Pool, suggesting a likely link between regional oceanographic climate and the expansion of cold-sensitive reef-building coral communities to the high-latitude reefs off southeast Florida. These findings not only extend the record of coral-reef development in southeast Florida into the late Holocene, but they also have important implications for future range expansions of reef-building coral communities in response to modern climate change.

Climate plays a central role in coral-reef development, especially in marginal environments. The high-latitude reefs of southeast Florida are currently non-accreting, relict systems with low coral cover. This region also did not support the extensive Late Pleistocene reef development observed in many other locations around the world; however, there is evidence of significant reef building in southeast Florida during the Holocene. Using 146 radiometric ages from reefs extending ~ 120 km along Florida’s southeast coast, we test the hypothesis that the latitudinal extent of Holocene reef development in this region was modulated by climatic variability. We demonstrate that although sea-level changes impacted rates of reef accretion and allowed reefs to backstep inshore as new habitats were flooded, sea level was not the ultimate cause of reef demise. Instead, we conclude that climate was the primary driver of the expansion and contraction of Florida’s reefs during the Holocene. Reefs grew to 26.7° N in southeast Florida during the relatively warm, stable climate at the beginning of the Holocene Thermal Maximum (HTM) ~ 10,000 years ago, but subsequent cooling and increased frequency of winter cold fronts were associated with the equatorward contraction of reef building. By ~ 7800 years ago, actively accreting reefs only extended to 26.1° N. Reefs further contracted to 25.8° N after 5800 years ago, and by 3000 years ago reef development had terminated throughout southern Florida (24.5–26.7° N). Modern warming is unlikely to simply reverse this trend, however, because the climate of the Anthropocene will be fundamentally different from the HTM. By increasing the frequency and intensity of both warm and cold extreme-weather events, contemporary climate change will instead amplify conditions inimical to reef development in marginal reef environments such as southern Florida, making them more likely to continue to deteriorate than to resume accretion in the future.

Fossil and subfossil specimens of the West Indian Top Shell, Cittariuin pica (Linnaeus, 1758) are found in the Pleistocene rocks and Holocene Native American middens in southeastern Florida. The occurrence of both living and fossil C. pica corresponds to hard substrate, represented by rocks exposed both above and below the water level. Pleistocene specimens are found in the Miami Limestone in Miami-Dade County and, for the first time, in the Anastasia Formation in Martin County. In both localities, C. pica are found in the vicinity of Pleistocene rocky shorelines. The same pattern is found for Holocene occurrences from archeological digs. Absence of C. pica in southern Florida today is likely related to the elimination of suitable habitats during the Holocene marine transgression.

SignificanceThe Chicxulub impact played a crucial role in the Cretaceous–Paleogene extinction. However the earliest postimpact effects, critical to fully decode the profound influence on Earth’s biota, are poorly understood due to a lack of high-temporal-resolution contemporaneous deposits. The Tanis site, which preserves a rapidly deposited, ejecta-bearing bed in the Hell Creek Formation, helps to resolve that long-standing deficit. Emplaced immediately (minutes to hours) after impact, Tanis provides a postimpact “snapshot,” including ejecta accretion and faunal mass death, advancing our understanding of the immediate effects of the Chicxulub impact. Moreover, we demonstrate that the depositional event, calculated to have coincided with the arrival of seismic waves from Chicxulub, likely resulted from a seismically coupled local seiche.