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Abstract Most species exhibit morphological stasis following speciation, and this is a key feature of the concept of punctuated equilibria. Stasis results in species often having long durations on geological timescales. Durational data are fundamental to many types of paleobiological analyses and are ideally based on occurrence data represented by specimens in museum collections. Often, however, durational data are presented without supporting information about voucher specimens that document stratigraphic ranges, including first and last appearances. We use the iconic Devonian trilobiteEldredgeops ranato demonstrate that durational data can be challenging to determine at multiple taxonomic levels. Further, we show that different datasets—including Sepkoski’s published databases, the Paleobiology Database, and iDigBio—give discordant results concerning first and last occurrences. We argue that paleontologists should adopt two general best practices to help address these problems. First, systematists should clearly identify voucher specimens that represent stratigraphic occurrences of species. Second, we recommend that high-quality photographs of occurrence vouchers be placed in open access websites and be assigned public domain licensing before being paywalled by journals. Such voucher images also have a role to play in training artificial intelligence (AI) systems that will be applied to future paleobiological questions. 

The Plio-Pleistocene turnover event in the western Atlantic following the closure of the Central American Seaway involved high rates of extinction for both gastropod and bivalve molluscs. This extinction was associated with declining nutrient conditions and has been presumed to be associated with a decrease in molluscan body size. Previous work which has been concordant with this expectation, however, has either focused on bivalves or not considered the effects of the recovery post extinction. In three phylogenetically diverse clades, we found that body-size evolution in gastropods across the turnover event is likely tied to ecology. One clade increased in size, one decreased, and another exhibited no substantial change. Individual species lineages exhibit a mixture of microevolutionary changes from the Pliocene to today. This study indicates that gastropod body-size evolution may be more complex than in bivalves, with ecology and other functional traits playing a significant role. Macroevolutionary processes, especially whether a clade re-radiated post extinction, were found to be important. Indeed, a low portion of extant diversity consists of survivors from clades that increased in size or have similar size distributions among their species relative to the Pliocene. 

The neogastropod clade Conoidea includes the familiar cone snails (Conidae) and 17 additional families, all but one of which (Cryptoconidae) are extant. There are over 5,000 extant species and 380 genera of Conoidea, all of which are venomous predators. Many conoideans other than Conidae and Terebridae (auger snails) are often called “turrids” and are often characterized by the presence of an indented “turrid notch” at the terminal edge of the shell's sutural ramp. Conoideans have a rich fossil record that extends to the Cretaceous, but a combination of hyperdiversity, subtle differences between species, often small shell size, and taxonomic complexity has resulted in them being little studied, despite their evolutionary success. We have begun to explore the fossil record of conoideans from the Plio-Pleistocene of the southeastern United States as part of a broader project to catalog and document the fossil records of all gastropod and bivalve species from this system. A newly developed database derived from literature and museum collections shows that nearly 200 species-group names have been applied to conoideans (excluding Conidae) from this system, fewer than 10 of which were described in the past 50 years. We present preliminary assessments of the Pliocene to Recent diversity patterns of individual subclades from the Southeast. Preliminary data from the Paleobiology Database demonstrate that occurrences assigned to the conoidean family Turridae from this study region are much less likely to be assigned to species than most other co-occurring mollusk families, with about 56% of occurrences assigned to a species. Online specimen data derived from the Florida Museum of Natural History similarly show that just under 50% of records from this system assigned to Turridae are also assigned to species. Because records unidentified to species are unevenly distributed among molluscan families, attempts to restrict analyses to only records which are well-resolved taxonomically may impact our overall understanding of biodiversity and ecology, especially when they result in the exclusion of species-rich clades. Our results highlight the importance of primary systematic research and museum collections for assessing important but understudied components of the biodiversity of fossil molluscan faunas. 

The influence of functional traits on species survivorship has been evaluated in various contexts in both modern and ancient ecosystems, but an important direction for research is to integrate datasets that include both extinct and extant taxa. This approach can provide a more reliable understanding of the effects of functional traits on macroecological and macroevolutionary dynamics. Knowledge of the links between individual traits and survivorship is crucial for developing accurate extinction risk predictive models. Here we test the impact of numerous functional traits on the survival and extinction of species through time, using bivalve and gastropod species from the rich fossil record of the western Atlantic over the last ~3 million years, along with the associated extant biota. We also compare the impact of these organismic traits on survival relative to a group level trait: geographic distribution. Analyses use a dataset of 12 functional traits including life habit, feeding behavior and basal metabolic rate (BMR), for 115 species from 36 families. Traits were observed and measured from specimens in the collections of the Paleontological Research Institution, Florida Museum of Natural History, and University of Kansas, as well as surveys of the literature and online databases such as the Neogene Marine Biota of Tropical America (NMITA). Results derived from Principal Coordinates Analysis (PCoA) show there is a clear distinction between extinct and extant species, overall, when comparing them based on life habit, maximum body size, shell composition and BMR. Most traits showed little direct relation with survival, except BMR and associated maximum body size, supporting the Metabolic Theory of Ecology. Since many functional traits do not explain survival, their function may be mis- or over-interpreted, and traits posited to represent important organismic adaptations may not play a prominent role in long-term species survival, especially during the major climate changes over the last ~ 3 million years. Some traits do show significant interactions, and these were more fully explored using additional multivariate analyses. The relative importance of geographic range size suggests group-level characters may be the primary determinant of extinction patterns over macroevolutionary time scales. 

Predicting the effects of anthropogenic climate change on Earth’s marine mollusk species is highly relevant, as many are critical human food resources and indispensable members of marine ecosystems. To predict which species will go extinct and which will survive, it is essential to understand the past climate species have experienced, as well as determine the relationship between functional traits, which provide a direct connection to organismal ecology, and survival. Many extant West Atlantic (WA) mollusks, especially gastropods and bivalves, survived the Mid-Pliocene Warm Period and the Last Interglacial, warm intervals compared to the present, that can serve as analogues for predicted future conditions of anthropogenic climate change. WA mollusks have an exceptional Neogene fossil record, which makes them an ideal group to study to develop a predictive extinction risk framework. The present research focuses on the correlation between functional traits and extinction in over 80 species of WA mollusks, both extant and extinct. Functional trait data such as body size, mobility, diet, bathymetric depth range, and organism-substrate relationship, which correlate with metabolic requirements, a known factor in extinction risk, and degree and type of ornamentation, shell shape in bivalves, and narrowness of the aperture in gastropods, which correlate with predation resistance, were collected across these species. These comprise both continuous and discrete character data. Various statistical tests were applied to the database to examine variable correlation/interaction, and the relative contributions of traits to extinction risk. Traits related to metabolism were strong predictors of survival; traits related to predation resistance play a less important role. While this study focuses on organismic traits, the aim of future research will be to explore how group characteristics such as geographic range are associated with functional traits and extinction risk for these species. A predictive framework is developed using patterns of extinction in the fossil record to infer survival of various species in the future, which will be relevant for evaluating the potential consequences of climate change, global change biology, and for determining which species should be targeted for conservation efforts. 

Preliminary data indicate between the latest Pliocene and recent approximately 85% of bivalves and 90% of gastropod species in Florida and the Atlantic Coastal Plain became extinct, with high levels of origination resulting in similar total species richness in the region today. We expected this event may have impacted molluscan body size as body size in mollusks is generally correlated with nutrient availability and primary productivity, which decreased following the Pliocene closure of the Central American Seaway. Previous work indicated small body size is associated with extinction survival during this event in both bivalves and gastropods. Where all extant and Pliocene members of surviving bivalve clades have been compared, these have also declined in size; comparable studies of all extant and Pliocene members of gastropod clades have not yet, however, been undertaken. We investigated 3 families of gastropods of differing ecology with both high turnover and at least one boundary-crossing lineage in order to assess the impact of the turnover event on each clade’s body size. These were the predatory Conidae, the herbivorous Tegulidae, and the suspension-feeding Turritellidae. These had approximately 65%, 75%, and 90% extinction, respectively, with modern­ diversity at 110%, 100%, and 10% of their respective Pliocene species richness in the region. Despite high levels of turnover, we found no general pattern of body-size change associated with the event either within clades or among boundary-crossing lineages. While many of the largest species of Conidae and Turritellidae did become extinct, this was balanced by the loss of smaller-bodied species, while the Tegulidae increased in size. Among ancestor-descendant pairs, 1 turritellid decreased in size while 1 remained unchanged, 4 Conidae decreased in size while 2 increased in size, and 1 tegulid increased in size. These data suggest that for gastropods there were complex interactions between ecology, extinction, origination, and body-size evolution associated with this event and that a more phylogenetically-diverse dataset is needed to determine whether generalizable patterns exist which may be used to predict responses to future environmental change.