Shifts in phenology have been one of the most frequently documented effects of climate change across a wide variety of taxonomic groups. These shifts can alter both species and ecosystem level processes and, for species of conservation concern, may impact the effectiveness of ongoing management programs. Here, we used ten breeding seasons (2010–2020) of drift fence data to quantify the breeding phenology of the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi) at two breeding wetlands in Florida. We then used downscaled climate projections from three Global Circulation Models (GCMs; Hadley Centre Global Environment Model 2 Earth Systems, Hadley Centre Global Environment Model 2 Carbon Cycle, and the Community Climate System model version 4) each with two emission scenarios to forecast how flatwoods salamander breeding phenology may change from 2030–2099. We combined these forecasts with an existing hydrologic model that was built using the same climate data to examine how wetland hydrology and phenology may interact to impact salamander recruitment in future years. We found that large movements (≥ 5 individuals) of adult salamanders moving into breeding wetlands were tightly linked to precipitation events with minimum temperatures above freezing, while juvenile emigration was less strongly tied to precipitation and occurred on more days than adult immigration. Under all six GCM-emission scenario combinations, only one scenario suggested that there would be fewer immigration opportunities by the year 2099, and two scenarios (both high emission) indicated that the timing of immigration may shift to later in the fall breeding period. All projections predicted that only a few years will have an ideal intersection of phenology and hydrology for flatwoods salamander reproduction but that many years would have marginal conditions where recruitment may still be possible. Because the frequency of successful breeding years affects population viability in flatwoods salamanders, ongoing management programs must ensure that populations are reproducing frequently enough to remain viable. Overall, our results indicate that altered wetland hydrology (e.g., shorter hydroperiods during the breeding season) and other effects of climate change (e.g., sea level rise) are more likely to contribute to flatwoods salamander declines over the next several decades than phenological shifts.

There are presently four recognized species of clinid (kelpfish family: Clinidae) on the west coast of North America: Gibbonsia elegans, G. metzi, G. montereyensis, and Heterostichus rostratus. In addition, Clark L. Hubbs proposed an endemic subspecies in the genus Gibbonsia on Guadalupe Island. Later investigations using allozymes indicated low levels of genetic diversity between populations and treated subspecies names as synonyms, leading to the present-day status of three species in the genus. Here, we use high-throughput sequencing and a combination of nuclear and mitochondrial markers to revisit the systematics and population structure of the genus Gibbonsia. We find that Guadalupe Island specimens that are morphologically identified as G. elegans form a distinct genetic lineage for both nuclear and mitochondrial markers, supporting Hubbs's hypothesis of a Guadalupe Island endemic, Gibbonsia erroli. Further, we find that while dispersal potential is high for all species in the genus, genome-wide markers and outlier analyses show population structure at short geographic distances, suggesting fine scale environmental variation leading to local adaptation.

Adaptation and modularity are two major features of morphological evolution that are increasingly investigated by modern macroevolutionary biologists. However, many such studies assume that adaptive processes or modularity are constant across species. Evolution of morphology and its modularity both relate to the ecological role of morphological traits. Here, we investigate whether morphological adaptation and modularity vary across families of the Neotropical superfamily Doradoidea, comprising the Aspredinidae (banjo catfishes), Auchenipteridae (driftwood catfishes), and Doradidae (thorny catfishes). We quantified morphological diversity using three-dimensional geometric morphometrics and estimated evolutionary rates, shifts between adaptive regimes, and evolutionary modularity and integration differences among families. We found that doradoids diversified into nine adaptive regimes across morphospace. We also found some significant differences in modularity and integration between families. Major morphological shifts have surprising correspondence to previously or currently recognized taxa within the Doradoidea. We found repeated, parallel evolution of body elongation across adaptive regimes, implying a role for selection in driving parallel evolution across a primary axis of shape diversification. However, modularity and integration do not necessarily shift in correspondence with shifts in morphological adaptive peaks.

Predators have evolved a variety of novel mechanisms for efficient prey location that rely on specific sensory modalities. Strike-induced chemosensory searching (SICS) is a behavior pattern common across squamate reptiles (snakes and lizards) where a series of specific searching behaviors are activated in the predator following the envenomating strike and immediate release of prey. Of all squamates, rattlesnakes (Crotalus spp.) have been studied most extensively for their SICS behavior, but field documentation of such behaviors is sparse and often lacking in detail. Our study took advantage of a wild population of Timber Rattlesnakes (Crotalus horridus) in the Ozark Mountains of northwest Arkansas. Individuals were implanted with radio transmitters as part of a larger study on the effects of supplemental rodent prey on the physiological ecology of C. horridus. From these supplemental feeding trials, we filmed n 5 10 successful episodes of SICS as rattlesnakes (n 5 7) struck, released, and relocated rodent prey. All rattlesnakes exhibited the typical phases of SICS (quiescence, searching, trailing), and though the duration of each phase did not differ, rates of tongue-flicking (RTF) and breathing significantly increased from quiescence to trailing. We noted rapid, shallow ventilation patterns in the rattlesnakes, burst-like ventilation (BLV), and propose that BLV functions to surveil volatile chemical cues in the environment. Rates of tongue-flicking are well known proxies for measuring vomerolfaction in squamates, and we suggest BLV may similarly serve as a proxy for estimating rates of olfaction. The short cycles of air exchange we quantified as BLV flush air across the olfactory epithelium and thus could serve to detect volatile chemical cues. Quantification of BLV may enable researchers to capture more information about the sensory processes involved in squamate foraging behavior.

Reliable length frequency distributions are useful tools for the assessment and management of fish populations. However, in situ estimation of fish length with single-camera video systems may be inaccurate. The use of allometric changes of eye diameter (ED) and head height (HH) was proposed as a promising technique to estimate fish length from single-camera footage. However, the method, so far, has proven to be effective for a limited number of species and families, and the replicability among taxa remains uncertain. We described the allometric patterns of eye diameter and head height for a set of Osteichthyes and Chondrichthyes bearing heterogeneous morphological, taxonomical, and habitat-type features from northern Patagonia, Argentina. To assess the usefulness of the method, we regressed fish length on the HH:ED ratio for each of 12 common species by using artificial neural network models and compared the results with those obtained by standard regression models. We found relevant variability in allometry among the species analyzed and described four general cases. Furthermore, artificial neural network models outperformed conventional regression, although both models converged to similar results for several species. Overall, our findings highlighted the utility of the allometry method and suggested an association of both allometric patterns and model performance with fish morphology and habitat type. Whereas osteichthyan reef species were highly suitable for using this technique, models obtained for chondrichthyans and fusiform body-shaped species were less accurate. Our findings have practical implications for the estimation of fish length using single-camera systems and provide a framework to understand the differential suitability of the allometric approach.

In the tadpoles of some anuran species, there is a set of one or more anterior labial tooth rows that are divided by the upper jaw sheath, which we call paraoral tooth rows. We studied the taxonomic distribution of these tooth rows based on published information and preserved specimens in 4,595 species of anurans from all currently recognized families. Paraoral rows were recorded in 594 species, most belonging to Ranoides and Anomocoela, but also occurring in Myobatrachoidea and a few notogaeanurans. The reconstruction of ancestral states indicated at least 15 independent origins of the character state during the evolutionary history of the anurans. The paraoral rows are a typical character of Anomocoela and Ranoides. The presence of paraoral rows was retained in both clades during their evolutionary history when specialized morphologies evolved, as long as labial teeth were not lost.