Chewing is a rhythmic oral behavior that requires constant modifications of jaw movements in response to changes in food properties. The food-specific kinematic response is dependent on the potential for kinematic flexibility allowed by morphology and modulation of motor control. This study investigates the effects of food toughness and stiffness on the amplitude and variability of jaw movements during chewing in a typical omnivorous mammalian model (pigs). Jaw movements were reconstructed using X-ray Reconstruction Of Moving Morphology (XROMM) and kinematic data associated with the amplitude of jaw pitch (opening-closing) and jaw yaw (mediolateral rotation) were extracted for each cycle. Between-food differences were tested for the amplitude of jaw movements during each phase of the gape cycle, as well as in their respective within-food variability, or stereotypy, as indicated by coefficients of variation. With increasing toughness, jaw pitch amplitude is decreased during fast close, larger and more stereotyped during slow close, smaller but more variable during slow open, and more variable during fast open. In addition, when chewing on tougher foods, the amplitude of jaw yaw during slow close only increases in a subset of individuals, but all become less variable (i.e., more stereotyped). In contrast, increasing food stiffness has no effect on the amplitude or the variability of jaw pitch, whereas jaw yaw increases significantly in the majority of individuals studied. Our data demonstrate that food stiffness and toughness both play a role in modulating gape cycle dynamics by altering the trajectory of jaw movements, especially during the slow-close phase and tooth-food-tooth contact, albeit differently. This highlights how a generalist oral morphology such as that of pigs (e.g., bunodont teeth lacking precise occlusion, permissive temporomandibular joint allowing extensive condylar displacements in 3 dimensions) enables organisms to not only adjust chewing movements in their amplitude, but also in their variability.

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Phytoplankton are key players in global biogeochemical cycles, and the effects of ocean warming on their carbon–nitrogen–phosphorus (CNP) stoichiometry, photosynthesis, size, morphology, growth rates, and other traits are of great ecological consequence. The physiological mechanisms of adaptation to temperature in phytoplankton are poorly understood, as are the consequences of the evolution of these processes (e.g., nutrient uptake, photosynthesis) for global biogeochemistry. In general, high temperatures favor smaller cells with higher surface area‐to‐volume ratios, but repeatable patterns in cellular CNP stoichiometry across temperature remain elusive. Here, we compared thermal reaction norms for cellular C, N, P, and chlorophyll a (Chl a) content and for carbon assimilation rate in replicate populations of the marine diatom Thalassiosira pseudonana evolved for 500 generations at 16°C and 31°C. We also examined the thermal reaction norms for cell volume and morphological traits. T. pseudonana has a cylindrical frustule and likely primarily exchanges materials with the environment through the round valve faces. We found that the 31°C‐selected T. pseudonana populations had smaller cells and higher per‐biovolume densities of nutrients and Chl a than the 16°C‐selected populations across assay temperatures but there were no detectable patterns in CNP stoichiometry. The 31°C‐selected populations also had higher valve surface area‐to‐cell volume ratio that increased more with temperature, suggesting better nutrient uptake capabilities than in the 16°C‐selected populations. Our study demonstrates that temperature‐dependent physiological plasticity may evolve differently at different temperatures and suggests that future phytoplankton communities will consist of smaller, more nutrient‐dense cells.

Parocnus dominicanus sp. nov. represents a new species of megalonychid ground sloth from theAltagracia Province of southeastern Dominican Republic. Specimens of multiple individuals, including oneassociated partial skeleton, were recovered from two separate underwater caves in the Parque Nacional delEste through collaborations with museums and cave divers between 2009–2013. Parocnus dominicanus sp.nov. is distinguished by its small size compared to that of P. serus, with percent differences in limb elementlengths ranging from 13−24%. Numerous cranial and post-cranial elements also exhibit morphological characterstates that are not attributable to size variations. The recovery of multiple individuals within each localitydemonstrates a size dimorphism, possibly sexual, which parallels patterns exhibited by P. serus. The twospecies are also geographically distinct, with no examples of co-occurrence at any localities to date. Parocnusdominicanus sp. nov. and P. serus share character states that are distinct from those of the Cuban species, P.browni, and which suggest differential usage of the forelimb. The exact age of the specimens described here isunknown, however, Parocnus has been dated to the Holocene in Haiti.http://zoobank.org/urn:lsid:zoobank.org:pub:12E495D3-E261-4522-9854-D3B4C2D5FFB8

Sport fisheries are frequent drivers of nonnative fish introductions throughout the inland waters of North America. These fisheries often value aggressive, large-bodied predators, and although they satiate angling demand they are also potentially problematic in systems that support imperiled species. The Tonguetied Minnow Exoglossum laurae is a rare species that maintains a disjunct distribution across small portions of four watersheds in the eastern and Midwestern United States, all of which are stocked with nonnative Brown Trout Salmo trutta for sportfishing. This study estimated habitat preferences for Tonguetied Minnow and Brown Trout in the Great Miami River, the westernmost drainage within the Tonguetied Minnow's range. Model data were based on eight water quality variables and seven stream habitat variables. Negative binomial regressions identified gradient, maximum water temperature, substrate, pool/glide habitat, total dissolved solids, and specific conductance as important predictors of the distribution of Tonguetied Minnow, whereas maximum water temperature and substrate were identified for Brown Trout. These reduced numbers of variables then served as input into maximum entropy species distribution models for Tonguetied Minnow and Brown Trout. Only gradient (model contribution [MC] = 46.9%; permutation importance [PI] = 11.6%) and maximum water temperature (MC = 44.2%; PI = 79.8%) contributed substantially to the species distribution model for Tonguetied Minnow, while maximum water temperature (MC = 63.4%; PI = 76.2%) and substrate (MC = 36.6%; PI = 23.8%) were important contributors for Brown Trout. Water temperature appears to exert the principal influence on the distributions of both species and supports the premise that these species share similar habitat preferences within the Great Miami River. Therefore, the Tonguetied Minnow is likely unable to avoid interspecific interactions, such as predation, posed by Brown Trout that are introduced for sportfishing, thus raising concerns about the conservation of this isolated and highly imperiled population.