Florida Keys Research Articles

AEDEOMYIA (AEDEOMYIA) SQUAMIPENNIS-NEW GENUS AND SPECIES COUNTY RECORD FOR MONROE COUNTY, FLORIDA, USA.

Aedeomyia (Aedeomyia) squamipennis is a tropical mosquito that has only recently been observed in the USA. Its natural range of Central and South America has been expanded to several Caribbean islands and mainland Florida in recent years and has now been found in the Florida Keys. Despite its association with the Gamboa virus and avian malaria, concern for establishment and vectorial capacity is diminished in the Florida Keys due to Ae. squamipennis's lack of preferred larval habitat.

Aedes pertinax, A Lost and Found New Species Record for Monroe County, Florida.

Aedes pertinax, a little-studied tropical mosquito that has found its way into the USA, has recently been discovered to have existed in the Florida Keys for almost 25 years. A 2021 collection of Ae. pertinax adult females in Key Largo, FL, sparked a retrospective search for stored specimens collected in 1998 on Big Pine Key, FL. Positive identification of the specimens from the 1998 collection confirmed the specimens to be Ae. pertinax, predating the first reported specimen in the USA by 13 years.

Mosquito Surveillance and Insecticide Resistance Monitoring Conducted by the Florida Keys Mosquito Control District, Monroe County, Florida, USA.

Simple SummaryMosquitoes are the most important group of flies affecting human health and wellness. Worldwide, mosquito-borne diseases kill over 700,000 people every year and afflict millions more. Mosquitoes also adversely affect domestic and agricultural animal health and negatively impact tourism-based economies. The Florida Keys Mosquito Control District is responsible for reducing mosquito populations in an area stretching from Cross Key and Broad Creek in the northeast to Key West in the southwest. Before mosquitoes can be controlled, it is important to know how many mosquitoes there are, what species are present, and where they are located. Adult mosquito surveillance traps such as the BG Sentinel, set around homes and businesses, and light traps, set in field sites, are used to identify the number and species of mosquitoes in an area. Larval and pupal mosquito surveillance is conducted by visiting water sources in domestic and field habitats to look for immature mosquitoes. Surveillance informs operational staff of the types of treatments required to control mosquitoes present. Products currently used to kill larval and adult forms of mosquitoes are continuously evaluated for efficacy to reduce pesticide-resistant populations.Mosquito control programs in the State of Florida are charged with protecting human and animal health, fostering economic development of the State, permitting enjoyment of the natural attractions in Florida, and improving the quality of life of citizens. Mosquito control programs must accomplish these tasks in such a manner as will protect the environment and terrestrial, marine, and freshwater ecosystems. The Florida Keys Mosquito Control District provides a science-based Integrated Pest Management mosquito control program to the residents of the Florida Keys, Monroe County, Florida. Operational decisions are based on surveillance of adult and immature mosquitoes. Mosquito populations are monitored by means of carbon dioxide-baited light traps BG Sentinel traps, truck traps, gravid traps, oviposition traps, and human landing rate counts. Larvae and pupae are monitored by inspections of natural and human-made immature habitats. Due to past and current reliance on chemical pesticides for control of mosquitoes, the District maintains a pesticide resistance detection program consisting of CDC bottle bioassays and larval bioassays, challenging local mosquito species with currently used adulticides and larvicides.

No apparent cost of disease resistance on reproductive output in Acropora cervicornis genets used for active coral reef restoration in Florida

As assisted sexual reproduction interventions continue to become embedded within coral reef restoration initiatives, it is important to understand the potential for trade-offs between key traits like reproductive output and disease resistance. Oocyte size and fecundity, quantitative measures of reproductive output and important life-history traits, can be used as proxies for coral reproductive success and health. Sexual reproduction, particularly gametogenesis, is an energetically costly process and at the physiological level, trade-offs are caused by competitive allocation of limited resources to various functions. However, resource allocation trade-offs may also have a genetic basis, and thus, different genets may differ in these aspects. Therefore, the purpose of this study was to assess the reproductive output of A. cervicornis genets with known white-band disease resistance or susceptibility by quantifying the number and size of oocytes within colonies maintained within Mote Marine Laboratory’s offshore coral spawning nursery in the Lower Florida Keys, USA. We also quantified the number of eggs and sperm packaged within gamete bundles that were collected during the August 2020 spawning event. Consistent with previous studies, we found a positive correlation between colony size and fecundity. Interestingly though, we found no evidence for a trade-off between disease resistance and reproductive output and instead found a negative correlation between disease susceptibility and oocyte size. These data are relevant for population management interventions and for managing broodstock used for active restoration where a suite of corals with different genotypes and phenotypes are continuously propagated and outplanted. Having a more comprehensive understanding of the fitness differences among candidates can help guide such efforts and ensure that a diversity of fit genets is used for restoration, which should ultimately support greater adaptive potential and population resilience.

#Sawfish: Social media to assess public perceptions, behaviors, and attitudes towards a critically endangered species

Monitoring population size and dynamics of threatened or low-density species is often both logistically difficult and costly. Recently, social media has emerged as a new tool for species monitoring. In this study, we expand on the use of social media posts as a tool to monitor the spatial and temporal distribution and public perceptions toward the smalltooth sawfish Pristis pectinata. We recorded 442 encounters with smalltooth sawfish from 2018 to 2021 in the form of Instagram posts. We identified locations of encounters within the following regions: Florida Keys, Everglades, South Florida (Miami/Fort Lauderdale), Caloosahatchee River, Bahamas, Upper Charlotte Harbor, Port St. Lucie, Ten Thousand Islands, Tampa, Naples, and Cape Canaveral. We found the greatest number of encounters occurred in the Florida Keys. In addition to spatiotemporal analysis, we used the captions of the posts to assess public attitudes and behaviors toward this charismatic species. This revealed individuals who encounter sawfish feel in general positive about their experience (over half described their encounter using positive language). We also found that sawfish were frequently caught as bycatch when other species (e.g., shark, tarpon, bonefish) were being targeted. Notably, in 12.6% of cases where sawfish were caught, they were being directly targeted. We also identified specific problematic or illegal handling behaviors from image and caption analysis. In addition to captured sawfish, we found sawfish are also frequently observed by beachgoers, boaters, and divers— however, in many cases these encounters may not be reported.

Cross-generational heritability analysis of physiological traits in Porites astreoides across an inshore-offshore gradient in the Lower Florida Keys

Estimating the heritable genetic variation in fitness-related traits is key to projecting the adaptive evolution of organisms in response to a changing environment. While heritability studies on reef-building corals to date support adaptive capacity, little is known about the dynamics of trait heritability across life stages in which distinct selective pressures can have long-lasting effects both within and across generations. In this study, we obtained heritability estimates for energetic and thermal stress response traits in adult, larval, and recruit Porites astreoides from two populations in the Lower Florida Keys. To induce bleaching phenotypes among individual families, larvae were exposed to a 4-day thermal stress at 32 °C, whereas adults and recruits received the same treatment for 22 days. Origin-dependent tolerance was observed in two life stages where offshore recruits lost more symbiont cells under heat than inshore recruits compared to their respective controls and heat-treated offshore adults suffered a greater loss in total protein content. Surprisingly, larvae appeared to be largely insensitive to heat regardless of origin. Broad sense heritability (H2) estimates varied greatly among traits and life stages, which may reflect changes in the relative importance of genetic and environmental variation throughout development. Over 50% of the variation in all larval traits, adult symbiont density and chlorophyll a concentration, and recruit protein content can be attributable to genetic factors. The overall moderate to high H2 estimates measured here suggest family-level variation can persist across different life stages and these corals may be equipped with considerable potential to adapt to environmental change.

Predator-Induced Nocturnal Benthic Emergence: Field and Experimental Evidence for an Unknown Behavioral Escape Mechanism along the Coral Reef–Seagrass Interface

Previously, using plankton tows, and emergence and settlement traps, we documented persistent widespread nocturnal emergence, and planktonic redistribution, of benthic macroinvertebrates along the coral reef–seagrass interface at two geographically separated locations. We also documented that emergence intensity varies with distance from the reef, leading us to hypothesize that the spatial pattern of emergence is determined by the foraging patterns of nocturnally active, bottom-feeding, mid-level consumers (mainly grunts). In this second study, we coupled those previously published data with nocturnal fish surveys concurrently conducted along belt transects placed at the same locations as the emergence trap collections, and a controlled laboratory experiment, to test this hypothesis. The results of these analyses find that variability in the density of nocturnally active, bottom-feeding fish is strongly positively correlated with emergence intensity, regardless of site or season. Results from the laboratory experiments show that nocturnal invertebrate emergence is significantly higher in the presence of one bottom-feeding fish (the blue-striped grunt Haemulon sciurus) than in microcosms that do not contain this predator. Overall, this study shows that such processes may explain how benthic prey can avoid capture by nocturnally active, bottom-feeding predators and persist in the predator-rich seagrass habitats that surround coral reefs in the Florida Keys National Marine Sanctuary. This study also points out the need to consider nocturnal processes when studying seagrass biodiversity in a predator-rich environment.

Relative sea-level change in South Florida during the past ~5000 years

A paucity of detailed relative sea-level (RSL) reconstructions from low latitudes hinders efforts to understand the global, regional, and local processes that cause RSL change. We reconstruct RSL change during the past ~5 ka using cores of mangrove peat at two sites (Snipe Key and Swan Key) in the Florida Keys. Remote sensing and field surveys established the relationship between peat-forming mangroves and tidal elevation in South Florida. Core chronologies are developed from age-depth models applied to 72 radiocarbon dates (39 mangrove wood macrofossils and 33 fine-fraction bulk peat). RSL rose 3.7 m at Snipe Key and 5.0 m at Swan Key in the past 5 ka, with both sites recording the fastest century-scale rate of RSL rise since ~1900 CE (~2.1 mm/a). We demonstrate that it is feasible to produce near-continuous reconstructions of RSL from mangrove peat in regions with a microtidal regime and accommodation space created by millennial-scale RSL rise. Decomposition of RSL trends from a network of reconstructions across South Florida using a spatio-temporal model suggests that Snipe Key was representative of regional RSL trends, but Swan Key was influenced by an additional local-scale process acting over at least the past five millennia. Geotechnical analysis of modern and buried mangrove peat indicates that sediment compaction is not the local-scale process responsible for the exaggerated RSL rise at Swan Key. The substantial difference in RSL between two nearby sites highlights the critical need for within-region replication of RSL reconstructions to avoid misattribution of sea-level trends, which could also have implications for geophysical modeling studies using RSL data for model tuning and validation.

2021 AMCA Presidential Address.

2021 AMCA Presidential Address.

Use of Vitex doniana (black plum) and Abutilon hirtum (Florida keys) extracts as an integral part of phytomedicine in tackling multidrug-resistant Salmonella.

The high prevalence and global spread of antibiotic resistance is driving the search for new antibacterial agents. Screening small molecules against specific bacterial targets has not yielded new compounds therefore functional assays and phenotypic screens are now being used. In Nigeria, drug resistance towards Salmonella is a major public health concern. Nine fully characterized clinical Salmonella isolates, from the Department of Medical Microbiology, Jos University Teaching Hospital, Plateau State, Nigeria, were screened by broth microdilution for susceptibility to fractionated ethanol extracts of Vitex doniana and Abutilon hirtum. This was compared to the control organism ATCC25922 and a range antibiotics: CH (chloramphenicol), SP (sparfloxacin), AM (amoxicillin), CN (gentamicin), S (streptomycin), PEF (pefloxacin). The most common resistance profile was AM,CN,S with most isolates susceptible to fluoroquinolones. Activity was detected from both plant extracts with MICs of extracted fractions ranging from 150 - 300 µg/mL. Interestingly both plants produced extracts with bactericidal activity from 300 - 600 µg/mL. V. doniana exhibited better activity against the resistant Salmonella strains in terms of greater inhibition zones, but A. hirtum extracts were more consistently active against all isolates. In comparison with the synthetic drugs, both plant extracts exhibited activity against more isolates - this activity was bactericidal. Nigeria needs better anti-salmonella products and these results represent a starting point for antibiotic drug discovery.

Millennia-old coral holobiont DNA provides insight into future adaptive trajectories.

Ancient DNA (aDNA) has been applied to evolutionary questions across a wide variety of taxa. Here, for the first time, we utilized aDNA from millennia-old fossil coral fragments to gain new insights into a rapidly declining western Atlantic reef ecosystem. We sampled four Acropora palmata fragments (dated 4215 BCE to 1099 CE) obtained from two Florida Keys reef cores. From these samples, we established that it is possible both to sequence aDNA from reef cores and place the data in the context of modern-day genetic variation. We recovered varying amounts of nuclear DNA exhibiting the characteristic signatures of aDNA from the A. palmata fragments. To describe the holobiont sensu lato, which plays a crucial role in reef health, we utilized metagenome-assembled genomes as a reference to identify a large additional proportion of ancient microbial DNA from the samples. The samples shared many common microbes with modern-day coral holobionts from the same region, suggesting remarkable holobiont stability over time. Despite efforts, we were unable to recover ancient Symbiodiniaceae reads from the samples. Comparing the ancient A. palmata data to whole-genome sequencing data from living acroporids, we found that while slightly distinct, ancient samples were most closely related to individuals of their own species. Together, these results provide a proof-of-principle showing that it is possible to carry out direct analysis of coral holobiont change over time, which lays a foundation for studying the impacts of environmental stress and evolutionary constraints.

No Longer “Confined to the Lower Keys of Florida”: Mainland United States Cultivation of Breadfruit (Artocarpus altilis) in a Changing Climate

Breadfruit (Artocarpus altilis) is a domesticated tree crop found throughout the insular Pacific and in other tropical regions of the world where it has been introduced, most notably in the Caribbean. Although breadfruit thrives in Hawai‘i, as it has since before European contact, efforts to introduce breadfruit to the mainland United States have been challenged by the tree’s intolerance for even mildly cold temperatures. Historically, only extreme southern Florida has been consistently warm enough to support breadfruit cultivation. Today, however, likely owing to warming temperatures associated with global climate change, but possibly also the selection of breadfruit varieties with improved cold tolerance, an increasing number of growers based throughout Florida are finding success cultivating breadfruit trees and producing fruit. Using a mixed-methods approach including interviews and surveys among forty-three Florida-based breadfruit growers, this article investigates the current status and geographical range of breadfruit in the mainland United States and considers both the sustainability implications and the remaining environmental challenges regarding its cultivation.

Norm power of scuba diving and snorkeling behaviors in the Florida Keys

The sustainability of recreation and tourism in coral reefs depends on ecological health and environmentally responsible behaviors in those ecosystems, which are partly guided by social norms. The power of social norms lies in the behavioral obligations imposed by a group, and in the informal sanctions enforced by others or felt by oneself when conforming to or violating those obligations. This study examined the norm power of 12 coral reef behaviors of non-resident SCUBA divers and snorkelers in the Florida Keys. In a mail questionnaire, respondents rated how obligated they were to do each of the 12 behaviors when diving or snorkeling on a coral reef, and how embarrassed (informal sanction) they would feel if they were seen violating each of those behaviors. Overall, the results showed that divers and snorkelers were obligated to do all 12 types of behaviors, but the amount of norm power was distinguished by the level of embarrassment varying between the two groups. High norm power values suggest that SCUBA divers and snorkelers self-regulate and enforce desirable behaviors within their activity groups. Relatively low norm power behaviors should be monitored and may need targeted communication strategies or management interventions to help instill a sense of obligation and sanction. These findings have important implications for monitoring behavioral compliance, promoting ocean stewardship, and establishing management policies to sustain coral reef ecosystem services.

Readiness at what cost? Trauma, displacement and opportunism in the Florida Keys

As more jurisdictions adopt climate and disaster readiness plans in response to disaster risk, the merits of climate resiliency, adaptation, and recovery processes and initiatives should be assessed based upon their outcomes as opposed to their stated or implied intentions. This should involve assessment of the experiences of early adopters, to assist localities with plans currently under development. The key question explored is what factors combine to exacerbate displacement risk in the long tail of a disaster aftermath, especially at the understudied intersection of political economy and disaster trauma? To address this question, I use in-depth interviews with residents of the lower Florida Keys in the aftermath of 2017's devastating Hurricane Irma, identifying a complex of drivers through which risk of unequal residential displacement took shape. Specifically, post-Irma bureaucratic delays contributed to trauma promoted displacement in local working communities; in some cases, these processes resulted from preparedness initiatives themselves. In addition to the well-known displacement that occurs immediately after a storm, this suggests that displacement risk may develop over long timeframes as residents are emotionally and materially worn down by repeated frustrations. Identifying how disaster readiness initiatives contribute to these processes emphasizes the need for enhanced attention to the places and populations that they are intended to protect, as well as the generative power of their interactions with everyday bureaucracy and government function. Furthermore, this community's experiences invite future research to better understand how resilience, adaptation, and public safety initiatives interact with political economic context in ways that can result in sociospatial inequality, providing caution and suggesting avenues for reform.

Intra-habitat structural complexity drives the distribution of fish trait groups on coral reefs

Three-dimensional (3D) habitat complexity is a primary driver of organism distribution and community structure across ecosystems. Identifying the specific metrics and spatial scales at which complexity is functionally important for communities is therefore a critical component in forecasting ecosystem function. Here we pair fish species traits with multiple metrics from habitat photogrammetry to evaluate the most important measures and scales of 3D complexity driving ecological functions within one of the most structurally diverse ecosystems on the planet: coral reefs. From May to July 2019, we collected high-resolution (1 cm) large- and small-scale intra-habitat (25 m2) structural complexity data across eight reefscapes (∼2500 m2) and conducted co-located fish functional group surveys in the Florida Keys, FL, USA. We used a hierarchical clustering analysis to group 80 observed fish species by four traits related to habitat use (social level, body size, crypsis, activity period) and feeding guild to generate mechanistic predictions about fish-habitat relationships. Evaluating relationships between the resulting trait-based functional groups (k = 9) and four metrics of intra-habitat complexity (large-scale vertical relief, and small-scale vector ruggedness [VRM], VRM deviation, and profile curvature) revealed that trait groups respond independently to the various measures and scales of reef complexity. While large-scale complexity (relief) is strongly related to the presence of solitary, cryptic, nocturnal carnivores, likely due to prey availability as well as day-time refuge opportunities, herbivore abundance is unaffected by increasing vertical relief, potentially due to predator avoidance. Instead, gregarious (i.e., schooling) herbivores increase with small-scale complexity measured by VRM and VRM deviation across reefscapes, while less gregarious herbivores only respond to small-scale complexity when these same measures occur in low-relief habitat, possibly due to a tradeoff between grazing resource availability and predator visibility. Our results reveal how unique elements of complexity provided by both biotic benthic communities as well as large-scale habitat features like vertical relief are differentially important to fish functional groups. The general relationships we identified using traits provide a framework for predicting fish community responses to changes in specific measures of structural complexity on coral reefs globally. Our work illustrates how preserving 3D habitat complexity by protecting or augmenting (e.g., via restoration) structure-forming organisms can support diverse organismal communities and overall ecosystem productivity.

Viruses of Atlantic Bonefish (Albula vulpes) in Florida and the Caribbean show geographic patterns consistent with population declines.

Atlantic Bonefish (Albula vulpes) are economically important due to their popularity with recreational anglers. In the State of Florida, USA, bonefish population numbers declined by approximately 60% between the 1990s and 2015. Habitat loss, water quality impairment, chemical inputs, and other anthropogenic factors have been implicated as causes, but the role of pathogens has been largely overlooked, especially with respect to viruses. We used a metagenomic approach to identify and quantify viruses in the blood of 103 A. vulpes sampled throughout their Western Atlantic range, including populations in Florida that have experienced population declines and populations in Belize, Mexico, Puerto Rico, and The Bahamas that have remained apparently stable. We identified four viruses, all of which are members of families known to infect marine fishes (Flaviviridae, Iflaviridae, Narnaviridae, and Nodaviridae), but all of which were previously undescribed. Bonefish from Florida and Mexico had higher viral richness (numbers of distinct viruses per individual fish) than fish sampled from other areas, and bonefish from the Upper Florida Keys had the highest prevalence of viral infection (proportion of positive fish) than fish sampled from any other location. Bonefish from Florida also had markedly higher viral loads than fish sampled from any other area, both for a novel narnavirus and for all viruses combined. Bonefish viruses may be indicators of environmentally driven physiological and immunological compromise, causes of ill health, or both.Supplementary informationThe online version contains supplementary material available at 10.1007/s10641-022-01306-9.

Sequencing Bait: Nuclear and Mitogenome Assembly of an Abundant Coastal Tropical and Subtropical Fish, Atherinomorus stipes.

Genetic data from nonmodel species can inform ecology and physiology, giving insight into a species’ distribution and abundance as well as their responses to changing environments, all of which are important for species conservation and management. Moreover, reduced sequencing costs and improved long-read sequencing technology allows researchers to readily generate genomic resources for nonmodel species. Here, we apply Oxford Nanopore long-read sequencing and low-coverage (∼1x) whole genome short-read sequencing technology (Illumina) to assemble a genome and examine population genetics of an abundant tropical and subtropical fish, the hardhead silverside (Atherinomorus stipes). These fish are found in shallow coastal waters and are frequently included in ecological models because they serve as abundant prey for commercially and ecologically important species. Despite their importance in sub-tropical and tropical ecosystems, little is known about their population connectivity and genetic diversity. Our A. stipes genome assembly is about 1.2 Gb with comparable repetitive element content (∼47%), number of protein duplication events, and DNA methylation patterns to other teleost fish species. Among five sampled populations spanning 43 km of South Florida and the Florida Keys, we find little population structure suggesting high population connectivity.

Using recreational tournament records to construct a 53-year time series of the Florida Keys recreational Bonefish fishery

Using recreational tournament records to construct a 53-year time series of the Florida Keys recreational Bonefish fishery

The past, present, and future of coral reef growth in the Florida Keys.

Coral‐reef degradation is driving global‐scale reductions in reef‐building capacity and the ecological, geological, and socioeconomic functions it supports. The persistence of those essential functions will depend on whether coral‐reef management is able to rebalance the competing processes of reef accretion and erosion. Here, we reconstructed census‐based carbonate budgets of 46 reefs throughout the Florida Keys from 1996 to 2019. We evaluated the environmental and ecological drivers of changing budget states and compared historical trends in reef‐accretion potential to millennial‐scale baselines of accretion from reef cores and future projections with coral restoration. We found that historically, most reefs had positive carbonate budgets, and many had reef‐accretion potential comparable to the ~3 mm year−1 average accretion rate during the peak of regional reef building ~7000 years ago; however, declines in reef‐building Acropora palmata and Orbicella spp. corals following a series of thermal stress events and coral disease outbreaks resulted in a shift from positive to negative budgets for most reefs in the region. By 2019, only ~15% of reefs had positive net carbonate production. Most of those reefs were in inshore, Lower Keys patch‐reef habitats with low water clarity, supporting the hypothesis that environments with naturally low irradiance may provide a refugia from thermal stress. We caution that our estimated carbonate budgets are likely overly optimistic; comparison of reef‐accretion potential to measured accretion from reef cores suggests that, by not accounting for the role of nonbiological physical and chemical erosion, census‐based carbonate budgets may underestimate total erosion by ~1 mm year−1 (−1.15 kg CaCO3 m−2 year−1). Although the present state of Florida's reefs is dire, we demonstrate that the restoration of reef‐building corals has the potential to help mitigate declines in reef accretion in some locations, which could allow some key ecosystem functions to be maintained until the threat of global climate change is addressed.

Allogromia Arnoldi n. sp.: Distribution, Phylogenetic Placement, Culture Methods, and Fine Structure of a New Monothalamid Foraminiferan

ABSTRACT Allogromiids, organic-walled foraminifera, are common members of foraminiferal associations in reef and back-reef settings of the Florida Keys and other locales, and many live in cryptic or otherwise protected microhabitats associated with macroalgae and seagrasses. A new species of Allogromia was isolated from the alga Dasycladus vermicularis (Scopoli) collected from prop-roots of the red mangrove, Rhizophora mangle (Linneaus), in Zane Grey Creek, Long Key, Florida. This species, Allogromia arnoldi n. sp., genetically matches sequences of undescribed and uncharacterized allogromiids deposited in GenBank from Cyprus and Jamaica. Allogromia arnoldi is genetically and morphologically distinct from A. laticollaris Arnold, A. laticollaris strain CSH, A. sp. NF (Lee & Pierce, 1963), environmental DNA sequences of morphologically unknown allogromiids, a number of freshwater forms, and several undescribed marine allogromiids known in the literature by nicknames (e.g., “squatter,” “rubble dome,” “twinkle”). This new species of Allogromia belongs to Clade M of the monothalamid foraminifera. Allogromia arnoldi appears to be broadly distributed, and it is fairly easy to isolate and rear in culture. Individuals typically have bright orange cytoplasm, a variable number of apertures, and can assume a wide range of shapes. Transmission electron microscopy (TEM) following high-pressure freezing and freeze substitution shows that the test has a complex fine structure that varies in thickness. It consists of two layers: a thick inner layer with a “herringbone” fine structure, and a thinner, outer electron-opaque mesh-like layer that occurs in patches. The number of nuclei varies per individual, and the non-reproductive nucleus is morphologically similar to that of many other monothalamid foraminifera.