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WhetherNanotyrannus lancensisrepresents a distinct taxon or an immatureTyrannosaurus rexis a decades-long controversy. TheN. lancensisholotype (CMNH 7541) is an isolated skull and ceratobranchials, but limb osteohistology ofNanotyrannus-like individuals implies that these individuals were immatureTyrannosaurus, suggesting that theN. lancensisholotype is also immature. We demonstrate that ceratobranchial (“hyoid”) histology is useful for ontogenetic assessment in extant and extinct archosaurs. The ceratobranchial histology of theN. lancensisholotype indicates that it was nearing or had reached skeletal maturity, suggesting that it is taxonomically distinct from the coevalTyrannosaurus rexand that Hell Creek (and equivalent) ecosystems supported a diverse assemblage of predatory dinosaurs approaching the Cretaceous-Paleogene extinction. 

Abstract Depuration, or the process of clearing impurities from the gut, is commonly applied to marine food products due to its efficacy in removing human pathogens from shellfish and edible ascidians. Recent studies also reported that depuration of filter-feeding animals helped reduce transient bacteria and identify resident symbionts in gut microbiome studies. Here, we examined the impact of depuration on bacteria in the branchial sac, gut, and hepatic gland of the solitary ascidian Pyura vittata. Replicates were kept in filtered seawater for 4 days prior to dissection (aquaria-depuration) and compared to samples that were immediately processed following collection (wild-no depuration) and replicates kept in unfiltered seawater for 4 days (aquaria-control). 16S rRNA gene sequence analysis revealed no significant differences among ascidian sources for microbial alpha-diversity but significant shifts in beta-diversity. Depuration reduced the number of core bacteria markedly (66%–84%) across all body regions, and bacteria that remained postdepuration consisted of genera associated with enhanced host health and resilience within other marine symbioses. Our results suggest that microbial profiles obtained following depuration do not substantially differ from those of nondepurated animals, but depuration can help differentiate transient from core and resident taxa in complex host–microbiome symbioses. 

California faces cycles of drought and flooding that are projected to intensify, but these extremes may impact water users across the state differently due to the region's natural hydroclimate variability and complex institutional framework governing water deliveries. To assess these risks, this study introduces a novel exploratory modeling framework informed by paleo and climate‐change based scenarios to better understand how impacts propagate through the Central Valley's complex water system. A stochastic weather generator, conditioned on tree‐ring data, produces a large ensemble of daily weather sequences conditioned on drought and flood conditions under the Late Renaissance Megadrought period (1550–1580 CE). Regional climate changes are applied to this weather data and drive hydrologic projections for the Sacramento, San Joaquin, and Tulare Basins. The resulting streamflow ensembles are used in an exploratory stress test using the California Food‐Energy‐Water System model, a highly resolved, daily model of water storage and conveyance throughout California's Central Valley. Results show that megadrought conditions lead to unprecedented reductions in inflows and storage at major California reservoirs. Both junior and senior water rights holders experience multi‐year periods of curtailed water deliveries and complete drawdowns of groundwater assets. When megadrought dynamics are combined with climate change, risks for unprecedented depletion of reservoir storage and sustained curtailment of water deliveries across multiple years increase. Asymmetries in risk emerge depending on water source, rights, and access to groundwater banks. 

Marine isopod fossils represent a small component of the crustacean fossil record, contrasting the exceptional modern diversity of marine representatives of Isopoda. Examination of previously documented isopod species therefore presents an opportunity to derive additional paleobiological and taphonomic insight of these rare fossils. Here we consider two clusters of Archaeoniscus brodiei from the Lower Cretaceous (middle to upper Berriasian) Intermarine Member of the Durlston Formation, England. The individuals within the clusters are mostly complete, of similar size ranges, and are preserved on two different bedding planes. After examining these individuals, we illustrate, for the first time, appendages and eyes of A. brodiei. The appendage morphology supports the interpretation of A. brodiei as an isopod adapted to a benthic lifestyle. We propose that isopods from the Durlston Formation follow similar taphonomic pathways to arthropods preserved within plattenkalk-like deposits, resulting in enrichment in calcium carbonate and phosphate. Finally, the clusters reflect gregarious activities that were preserved during hypoxic events brought on by concurrent decay of algal blooms. 

ABSTRACT ObjectiveThe objective of this study was to examine the movements of Common Snook Centropomus undecimalis, a tropical euryhaline species, out of the Shark River, Everglades National Park, Florida, USA, and gain a better understanding of their long-distance regional movements. MethodsThis study used 7 years (2017–2023) of acoustic telemetry data from the Shark River Florida Coastal Everglades Array and from five other collaborative telemetry arrays in southwestern Florida to assess out-of-system movements for 119 Common Snook. Generalized linear models were used to assess the relationships between out-of-system movements and biological and environmental variables. ResultsMost Common Snook departures took place during the spawning season, with 121 departures (80.1%). Of 67 departed individuals, 26 were detected by the collaborative arrays (both north and south of our array, 38.8%). Of the departed Common Snook, 35 returned to the Shark River (52.2%), with most returning to the lower river (62.7%), and with a trend for larger fish to have a higher probability of return. Last, Common Snook that spent less time outside were more likely to return to the upper part of the Shark River. ConclusionsOur study leveraged five collaborative acoustic telemetry arrays to investigate long-distance movements of Common Snook across southwest Florida, revealing that the true scales of movement and population connectivity remain largely unknown. Despite limited receiver coverage, detections of Common Snook outside the Shark River were higher than expected, with half of the individuals exhibiting site fidelity by returning to the river. These findings underscore that a single river system may only represent a portion of an organism’s home range, highlighting the need for further studies and expanded receiver coverage to elucidate broader patterns of snook movement and population connectivity.