Northern Species Research Articles

Corrigendum

Corrigendum

A New Jurassic Kempynine Species With Notes on Historical Distributions of Kempyninae Integrated Both Fossil and Extant Taxa (Neuroptera: Osmylidae)

The extant kempynines, a strict “southern group,” are confined to South America and Australia, while their most fossil relatives are abundantly recorded in the Northern Hemisphere. This pattern of the biogeographic distribution implies the complicated evolutionary scenario of Kempyninae. Herein, a new northern species Arbusella platyptera Ma et Wang, sp. nov. is described from the Jiulongshan Formation in Daohugou, Inner Mongolia, China. Additionally, a key to the extinct species and extant genera of Kempyninae is provided. Integrating all extant and most fossil genera of Kempyninae, we conducted phylogenetic analyses to explore the inner relationships of Kempyninae for the first time. The results corroborate the monophyly of Kempyninae and retrieve three clades within the subfamily, namely, two northern fossil genera (†Arbusellla + †Jurakempynus), constituting the basalmost clade and three other northern fossil genera (†Sauktangida + †Mirokempynus + †Ponomarenkius), forming a monophylic clade, which is sister to the third clade that includes all extant southern genera and the southern fossil genus of †Euporismites. Also, the extant kempynines were hypothesized to evolve independently from their northern Mesozoic relatives. The Dispersal-vicariance (DIVA) analysis revealed a northern and prepangean origin of Kempyninae, and the northern ancestral kempynines first colonized the Southern Hemisphere before the split of Pangea. Our results expose a more complicated evolutionary scenario of the insects with a long evolutionary history and provide new insights into the formation of distribution patterns in current relictual insects.

Climate change reshuffles northern species within their niches

Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species’ positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with changing climate remains unclear. Here we analysed four decades of data for 1,478 species of birds, mammals, butterflies, moths, plants and phytoplankton along a 1,200 km high latitudinal gradient. The relative importance of climatic drivers varied non-uniformly with progressing climate change. While species turnover among decades was limited, the relative position of species within their climatic niche shifted substantially. A greater proportion of species responded to climatic change at higher latitudes, where changes were stronger. These diverging climate imprints restructure a full biome, making it difficult to generalize biodiversity responses and raising concerns about ecosystem integrity in the face of accelerating climate change.

Anguilla sp. diseases diagnoses and treatments: The ideal methods at the crossroads of conservation and aquaculture purposes

Anguilla anguilla, A.japonica and A.rostrata are the most fished and consumed eel species. However, these species are Critically Endangered, Endangered and Endangered, respectively. A combination of factors is thought to be responsible for their decline including fisheries, climate change, habitat destruction, barriers to migration, pollution and pathogens. Among them, viruses, bacteria and parasites are causing weakening of wild eels and serious economic losses for fishermen and eel farmers. Early detection of pathogens is essential to provide appropriate responses both for conservation reasons and to limit economic losses. Classic diagnosis approaches are time consuming and invasive and usual treatments, for example, antipathogenic substances are becoming obsolete because of pathogen resistance and environmental impact problems. The need for early and non-invasive diagnostic methods as well as effective and environmentally friendly treatments has increased. Vaccine development and diet supplementation have known a growing interest since their use could allow prevention of diseases. In this review, we summarize the main pathogens-viruses, bacteria and parasites-of the three northern temperate eel species, the methods used to detect these pathogens and the different treatments used. We discussed and highlighted the need for non-invasive, rapid and efficient detection methods, as well as effective and environmentally friendly treatments for both conservation and aquaculture purposes.

Foliar nutrient concentrations of six northern hardwood species responded to nitrogen and phosphorus fertilization but did not predict tree growth.

Foliar chemistry can be useful for diagnosing soil nutrient availability and plant nutrient limitation. In northern hardwood forests, foliar responses to nitrogen (N) addition have been more often studied than phosphorus (P) addition, and the interactive effects of N and P addition have rarely been described. In the White Mountains of central New Hampshire, plots in ten forest stands of three age classes across three sites were treated annually beginning in 2011 with 30 kg N ha−1 y−1 or 10 kg P ha−1 y−1 or both or neither–a full factorial design. Green leaves of American beech (Fagus grandifolia Ehrh.), pin cherry (Prunus pensylvanica L.f.), red maple (Acer rubrum L.), sugar maple (A. saccharum Marsh.), white birch (Betula papyrifera Marsh.), and yellow birch (B. alleghaniensis Britton) were sampled pre-treatment and 4–6 years post-treatment in two young stands (last cut between 1988–1990), four mid-aged stands (last cut between 1971–1985) and four mature stands (last cut between 1883–1910). In a factorial analysis of species, stand age class, and nutrient addition, foliar N was 12% higher with N addition (p < 0.001) and foliar P was 45% higher with P addition (p < 0.001). Notably, P addition reduced foliar N concentration by 3% (p = 0.05), and N addition reduced foliar P concentration by 7% (p = 0.002). When both nutrients were added together, foliar P was lower than predicted by the main effects of N and P additions (p = 0.08 for N × P interaction), presumably because addition of N allowed greater use of P for growth. Foliar nutrients did not differ consistently with stand age class (p ≥ 0.11), but tree species differed (p ≤ 0.01), with the pioneer species pin cherry having the highest foliar nutrient concentrations and the greatest responses to nutrient addition. Foliar calcium (Ca) and magnesium (Mg) concentrations, on average, were 10% (p < 0.001) and 5% lower (p = 0.01), respectively, with N addition, but were not affected by P addition (p = 0.35 for Ca and p = 0.93 for Mg). Additions of N and P did not affect foliar potassium (K) concentrations (p = 0.58 for N addition and p = 0.88 for P addition). Pre-treatment foliar N:P ratios were high enough to suggest P limitation, but trees receiving N (p = 0.01), not P (p = 0.64), had higher radial growth rates from 2011 to 2015. The growth response of trees to N or P addition was not explained by pre-treatment foliar N, P, N:P, Ca, Mg, or K.

MIS 5e sea-level history along the Pacific coast of North America

Abstract. The primary last interglacial, marine isotope substage (MIS) 5e records on the Pacific coast of North America, from Washington (USA) to Baja California Sur (Mexico), are found in the deposits of erosional marine terraces. Warmer coasts along the southern Golfo de California host both erosional marine terraces and constructional coral reef terraces. Because the northern part of the region is tectonically active, MIS 5e terrace elevations vary considerably, from a few meters above sea level to as much as 70 m above sea level. The primary paleo-sea-level indicator is the shoreline angle, the junction of the wave-cut platform with the former sea cliff, which forms very close to mean sea level. Most areas on the Pacific coast of North America have experienced uplift since MIS 5e time, but the rate of uplift varies substantially as a function of tectonic setting. Chronology in most places is based on uranium-series ages of the solitary coral Balanophyllia elegans (erosional terraces) or the colonial corals Porites and Pocillopora (constructional reefs). In areas lacking corals, correlation to MIS 5e often can be accomplished using amino acid ratios of fossil mollusks, compared to similar ratios in mollusks that also host dated corals. Uranium-series (U-series) analyses of corals that have experienced largely closed-system histories range from ∼124 to ∼118 ka, in good agreement with ages from MIS 5e reef terraces elsewhere in the world. There is no geomorphic, stratigraphic, or geochronological evidence for more than one high-sea stand during MIS 5e on the Pacific coast of North America. However, in areas of low uplift rate, the outer parts of MIS 5e terraces apparently were re-occupied by the high-sea stand at ∼100 ka (MIS 5c), evident from mixes of coral ages and mixes of molluscan faunas with differing thermal aspects. This sequence of events took place because glacial isostatic adjustment processes acting on North America resulted in regional high-sea stands at ∼100 and ∼80 ka that were higher than is the case in far-field regions, distant from large continental ice sheets. During MIS 5e time, sea surface temperatures (SSTs) off the Pacific coast of North America were higher than is the case at present, evident from extralimital southern species of mollusks found in dated deposits. Apparently, no wholesale shifts in faunal provinces took place, but in MIS 5e time, some species of bivalves and gastropods lived hundreds of kilometers north of their present northern limits, in good agreement with SST estimates derived from foraminiferal records and alkenone-based reconstructions in deep-sea cores. Because many areas of the Pacific coast of North America have been active tectonically for much or all of the Quaternary, many earlier interglacial periods are recorded as uplifted, higher-elevation terraces. In addition, from southern Oregon to northern Baja California, there are U-series-dated corals from marine terraces that formed at ∼80 ka, during MIS 5a. In contrast to MIS 5e, these terrace deposits host molluscan faunas that contain extralimital northern species, indicating cooler SST at the end of MIS 5. Here I present a review and standardized database of MIS 5e sea-level indicators along the Pacific coast of North America and the corresponding dated samples. The database is available in Muhs et al. (2021b; https://doi.org/10.5281/zenodo.5903285).

Incongruent latitudinal patterns of taxonomic, phylogenetic and functional diversity reveal different drivers of caddisfly community assembly across spatial scales

AbstractAimCommunity assembly processes are difficult to observe in nature but can be inferred from species diversity patterns. However, taxonomic patterns may be consistent with multiple explanations, such as habitat filtering or biogeographical processes, which can also act differently across spatial scales. Here, we assessed multiple facets of diversity to determine the relative contributions of local versus regional processes and historical versus contemporary factors in establishing macroecological patterns.LocationFrom the Mediterranean peninsulas to northern Scandinavia.Time periodSpecies occurrence data gathered since c. 1980.Major organism group studiedTrichoptera (Insecta).MethodsBased on an extensive functional space and a phylogenetic tree including 197 and 509 species, respectively, and the composition of 180 communities, we assessed the distribution of taxonomic, functional and phylogenetic diversity within 18 ecoregions (local α‐ and β‐diversity) and among those ecoregions (regional γ‐ and β‐diversity).ResultsLocal estimates of taxonomic, functional and phylogenetic α‐ and β‐diversity were similar across Europe, which reveals that all streams have similar carrying capacity even though the local abiotic factors involved are likely different among ecoregions. In contrast, regional taxonomic and phylogenetic diversities decreased as latitude increased, whereas functional richness and functional dispersion displayed unimodal relationships. The position of species on the functional space was not conserved, while northern species pools were found to be phylogenetically clustered and southern ones overdispersed. The nestedness component mainly contributed to the taxonomic and phylogenetic β‐diversity among northern communities, whereas in southern latitudes the turnover was dominant.Main conclusionsDecoupled latitudinal patterns of taxonomic, phylogenetic and functional diversity reveal the importance of regional environmental filtering over local factors in limiting species range and shaping the regional species pool. The biogeographical signature is still present; the northern recolonizations following the Pleistocene glaciations originated exclusively from central regions, instead of Mediterranean refugia, as was previously accepted.

Atmospheric particulate matter deposition on birch catkins and pollen grains before pollination

Birch is the most allergenic tree species in Northern and Central Europe. Airborne birch pollen concentrations are observed to be on the rise for several decades. Health hazard due to birch pollen grains (BPGs) can worsen due to particulate air pollution. The prevalence of the intimate mixture of BPGs with atmospheric particulate matter (APM) at the single pollen grain level is still unraveled. In this study, APM transfer mechanisms to birch catkins and BPGs prior to pollination were investigated at an urban-industrial and a peri-urban site in Northern France. The surface of catkins was heavily polluted with micrometer-sized particles. Conversely, BPGs were relatively unpolluted with on average 0.1 particle.BPG−1. Differences in the chemical composition of adhered particles were observed as a function of the sampling sites. In contrast, no significant difference was found in terms of surface concentrations of APM adhered to BPGs and catkins between the two sites. Comparison of the number of particles deposited per pollen grain according to whether they were harvested from catkins or collected while airborne suggests that particulate pollution of pollen occurs preferentially after pollen shedding, either by impaction or coagulation mechanisms with other suspended APM or by pollen settling on dust-contaminated surfaces followed by resuspension.

Assessment of the thermotolerance of leaves of spontaneous oak species in northern and central Republic of Moldova

Understanding how the leaves of oak species trees respond to the action of thermal stress is essential in assessing their ability to adapt and in predicting their spread in the conditions of future increase in ambient temperature. In this study, the thermotolerance of tree leaves of the species was investigated: pedunculate oak, sessile oak and downy oak after the exposure of limb foliate samples to thermal shock with a temperature of 59° C for different periods of time. With the help of the electrolyte leakage method, the functional resistance of the leaves to the oak species was compared, not avoiding the avoidance phenomena. Based on the index of relative leakage of electrolytes from the tissues, the functional features of the leaves of oak species, which grow under certain environmental conditions in the Republic of Moldova, were examined. It has been shown that the thermotolerance of oak species changes depending on their biological characteristics and the environmental conditions in which the trees grow. Based on the lethal dose values (LD50), it was established that in the northern part of the Republic of Moldova the leaves of pedunculate oak are characterized by a slightly higher resistance, while those of downy oak show a somewhat higher sensitivity. In the stands in the center of the Republic of Moldova, the resistance of the downy oak leaves has obviously increased and the tolerance of the pedunculate oak ones has decreased.

Characterization of Hantavirus N Protein Intracellular Dynamics and Localization.

Hantaviruses are enveloped viruses that possess a tri-segmented, negative-sense RNA genome. The viral S-segment encodes the multifunctional nucleocapsid protein (N), which is involved in genome packaging, intracellular protein transport, immunoregulation, and several other crucial processes during hantavirus infection. In this study, we generated fluorescently tagged N protein constructs derived from Puumalavirus (PUUV), the dominant hantavirus species in Central, Northern, and Eastern Europe. We comprehensively characterized this protein in the rodent cell line CHO-K1, monitoring the dynamics of N protein complex formation and investigating co-localization with host proteins as well as the viral glycoproteins Gc and Gn. We observed formation of large, fibrillar PUUV N protein aggregates, rapidly coalescing from early punctate and spike-like assemblies. Moreover, we found significant spatial correlation of N with vimentin, actin, and P-bodies but not with microtubules. N constructs also co-localized with Gn and Gc albeit not as strongly as the glycoproteins associated with each other. Finally, we assessed oligomerization of N constructs, observing efficient and concentration-dependent multimerization, with complexes comprising more than 10 individual proteins.

Southern hemisphere plants show more delays than advances in flowering phenology

Abstract Shifts in flowering phenology have been studied in detail in the northern hemisphere and are a key plant response to climate change. However, there are relatively fewer data on species' phenological shifts in the southern hemisphere. We combined historic field data, data from herbarium specimens dating back to 1842 and modern field data for 37 Australian species to determine whether species were flowering earlier in the year than they had in the past. We also combined our results with data compiled in the southern and northern hemispheres, respectively, to determine whether southern hemisphere species are showing fewer advances in flowering phenology through time. Across our study species, we found that 12 species had undergone significant shifts in flowering time, with four species advancing their flowering and eight species delaying their flowering. The remaining 25 species showed no significant shifts in their flowering phenology. These findings are important because delays or lack of shifts in flowering phenology can lead to mismatches in trophic interactions between plants and pollinators or seed dispersers, which can have substantial impacts on ecosystem functioning and primary productivity. Combining our field results with data compiled from the literature showed that only 58.5% of southern hemisphere species were advancing their flowering time, compared with 81.6% of species that were advancing their flowering time in the northern hemisphere. Our study provides further evidence that it is not adequate for ecologists to assume that southern hemisphere ecosystems will respond to future climate change in the same way as ecosystems north of the Equator. Synthesis. Field data and data from the literature indicate that southern hemisphere species are showing fewer advances in their flowering phenology through time, especially in comparison to northern hemisphere species.

Deep and cold: are Boreal and Arctic finned octopods, Stauroteuthis syrtensis and Cirroteuthis muelleri (Cephalopoda, Octopoda, Cirrata), ecological analogues?

Stauroteuthis syrtensis and Cirroteuthis muelleri were studied based on representative material collected in Greenland, Iceland, and the Barents Sea and adjacent deep-sea areas (96 stations and 165 individuals for S. syrtensis, and 82 stations and 215 individuals for C. muelleri). The species occur on the border of the Arctic and the northern North Atlantic; S. syrtensis is a southern species and C. muelleri is a northern species, in the area from the Denmark and Davis Straits and associated underwater ridges. These species were demonstrated to be ecological analogues since they: a) occupy the same depths; b) reach the same abundance density; c) reach virtually the same biomass density when corrected for size differences; and d) their food spectra largely coincide. Temperature, not depth, is a principal factor that prevents these species from crossing the border between the Arctic and the northern North Atlantic, with mean habitat temperatures of 3.5 ± 0.06 °C for S. syrtensis and 0.3 ± 0.06 °C for C. muelleri. This study provides unprecedented density estimates for the North Atlantic and Arctic Cirrata: the highest in the world ocean in terms of biomass and second highest in terms of numerical abundance. Food spectra of the studied species consist of Calanoida (including eurybathic Paraeucheta spp. and Calanus spp., and deep-sea Bradyidius similis), Mysidacea and Isopoda (including deep-sea Eurycopinae) (Crustacea), and in C. muelleri also Cumacea, Amphipoda (Crustacea) and Polychaeta (Polynoidae). Additionally, this study: a) provides specific growth and morphometric equations; b) provides equations to estimate mantle length (ML) and body mass (BM) from beak measurements, and BM of fresh individuals (for modelling purposes or predators diet analyses) from BM of fixed individuals; c) reports maximum sizes for C. muelleri (ML 170 mm, total length 400 mm, BM 781.0 g); and d) reports findings of rarely encountered juvenile cirrates.

Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America

Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America

Dissimilar use of an external heat source for thermoregulation by shrews from different geographic regions

Ambient temperature has a substantial influence on the thermoregulation costs of small mammals due to their high surface-to-volume ratio. Shrews are among the smallest of mammals and have adopted different behavioral and physiological strategies to deal with cold temperatures. In this study, we assessed the use of an external heat source in the thermoregulatory strategy of two Crocidurinae species, Crocidura russula and C. suaveolens, and one Soricinae species, Sorex araneus. Crocidura russula inhabits western Europe and is better adapted to a Mediterranean climate; C. suaveolens inhabits central Europe; and S. araneus inhabits northern Europe and is better adapted to a Palearctic climate. We predicted that C. russula (most southern species) would spend larger amounts of time using an external heat source because it is the most cold-sensitive species, while S. araneus (most northern species) would spend less time using an external heat source or not respond to it. Shrews were experimentally tested in captivity inside a terrarium where they had access to a heat rock, which could be turned off (cold) or on (heated), depending on treatment. Our results confirmed our initial prediction: C. russula was the species that spent significantly more time on the heated rock, followed by C. suaveolens. Only a quarter of S. araneus individuals spent large amounts of time on the heat rock, which suggests this thermoregulation strategy is not generally adopted by this species, but may be rather associated with some individual personalities. We also analyzed the influence of the heat rock on rewarming from heterothermy, but heterothermy was not different between rock treatments. Overall, our results show that shrew species use external heat sources for thermoregulation according to their sensitivity to cold.

Range expansion of tropical shallow-water marine molluscs in the NE Atlantic during the last interglacial (MIS 5e): Causes, consequences and utility of ecostratigraphic indicators for the Macaronesian archipelagos

Controlled by ecological and physical factors, marine species distribution may vary due to global climatic changes that result from range expansion or contraction (the latter caused by local disappearances, i.e., extirpations). Spanning from 13° to 39°N, the Macaronesian region encompasses five archipelagos located within warm-temperate to tropical climatic zones and influenced by a surface water current regime that favours a N–S range expansion of marine species. The extensive and well-preserved Macaronesian fossil record makes these islands excellent candidates for evolutionary studies. It documents a northward range expansion of tropical species with a Cabo Verdean-Mauritanian-Senegalese biogeographic provenance during the Last Interglacial (LIG). For the first time, a thorough revision and update of marine molluscs’ checklist from the Macaronesian archipelagos for the LIG is presented. On this basis, we hypothesize that the range expansion occurred during the last phase of glacial Termination 2 and was enhanced by ephemeral sea surface currents that created windows of opportunity for the long-distance dispersal of marine species along sweepstake routes. During these short intervals of time, numerous tropical and subtropical species expanded their geographic range northwards, towards what today are subtropical and temperate archipelagos. Simultaneously, however, a smaller number of northern species expanded their ranges southward, some reaching Cabo Verde. This work yields a set of 24 mollusc “ecostratigraphic indicators” (10 bivalve and 14 gastropod species) that are important to identify fossiliferous deposits from the Last Interglacial epoch in Macaronesian archipelagos. Longitudinal range expansions from West African shores to the Cabo Verde archipelago and the Canary Islands were also detected. These are related to coeval weaker upwelling systems which now constitute effective barriers for the exchange of species/individuals between continental and insular shores (e.g., Senegal/Cabo Verde; Morocco/Canaries). Finally, an ecological filter-effect also existed, which we associate with the increasingly longer distances to cover, as many of the most typical representatives of the warm water fauna with Cabo Verde/Senegalese affinities failed to reach the northern Azores and Madeira archipelagos.

Emergence phenology of Tasmanian mayflies (Ephemeroptera) in a first-order creek and comparison with northern hemisphere confamilials

Context Australian mayflies are hypothesised to differ from those in the Northern Hemisphere by having longer, more variable emergence seasons that overlap more widely among taxa. Aim To test this hypothesis by comparing the behaviour of related northern and southern hemisphere species in similar habitats and at similar spatial scales. Methods Emergence dates were recorded fortnightly over two consecutive years, one ‘warm’ and one ‘cool’, in a rocky creek in south-eastern Tasmania, and at a coarser scale for Tasmania as whole, spanning an ∼20-year period. The results are compared with emergence patterns at two sites in the northern hemisphere climatically similar to Tasmania. Key results Durations of emergence seasons in Tasmania did not differ significantly at either the single site or whole of island scales from those in the northern hemisphere, but unlike in the latter, the start of emergence does not appear to be temperature-dependent. Conclusions Apparent regional differences are likely to result primarily from climatically inappropriate comparisons rather than from fundamental differences in behaviour. Implications Differences in the factor(s) that cue emergence suggest that the life histories of mayflies in Tasmania, and possibly elsewhere in Australia, are determined less by physiology than by aquatic ecology.

Cladocera remains in reconstructions of past ecological conditions of the Yamal Peninsula

Abstract. The aim of this study is to explore the Cladocera community from the bottom sediments of small unnamed lake (21-Ya-02B) whilst attempt to reconstruct the ecological and climatic conditions for the Yamal Peninsula. In total, remains of 37 taxa were identified in bottom sediments of the lake. Cladocera community in the lower layers at the column is represented by low taxonomic abundance and typical northern species. On the depth of 65-40 cm the maximum number of taxa was identified, which allows it to be considered the temperature optimum zone of Cladocera. Changes in the upper layers of the column may indicate climate warming in the study area and, as a consequence, thawing of permafrost.

Ecology, conservation status, and phylogenetic placement of endemic Pristimantis frogs (Anura: Craugastoridae) in Trinidad and Tobago and genetic affinities to northern Venezuela

AbstractTrinidad and Tobago are home to three endemic species in the anuran genus Pristimantis, of which two (Pristimantis charlottevillensis and Pristimantis turpinorum) occur in Tobago alone and the third (Pristimantis urichi) is present on both islands. Earlier, the IUCN assessed the conservation status of these species as: P. urichi, Endangered (EN); P. charlottevillensis, Least Concern (LC); P. turpinorum, Vulnerable (VU). However, these assessments were based on very little field‐based evidence. Here, we present survey results which contributed to reassessments as LC, VU and Data Deficient for these three species, respectively. Despite the close proximity of Trinidad to northern Venezuela, the islands do not share any Pristimantis species with the mainland, which holds a rich endemicity of Pristimantis regionally. In this study, we used genetic sequencing from several island populations and compared them to northern Venezuelan endemics to assess genetic divergence for the first time. The time tree analyses found that only the northern Tobago species P. turpinorum is closely related to mainland Pristimantis, with a genetic split dating to the Late Miocene, suggesting a vicariant event of mainland and island species. Pristimantis urichi, although identical between the two islands, remains highly divergent from the mainland species. Similar results were found for P. charlottevillensis. In addition, there was a high level of divergence between P. urichi and P. charlottevillensis. These findings indicate different island colonization events by different lineages. Sequencing other Venezuelan species remains pivotal to unravel the complexity of the colonization episodes in the region, likely influenced by the changing topography and multiple connection and isolation episodes of the islands by eustatic sea‐level changes.

Putting the Pacific marine heatwave into perspective: The response of larval fish off southern California to unprecedented warming in 2014-2016 relative to the previous 65 years.

The 2014-2016Northeast Pacific marine heatwave (MHW) induced the warmest 3-year period on record in the California Current Ecosystem. We tested whether larval fish assemblage structure, phenology, and diversity dynamics were comparable to past warming events from 1951 to 2013. First, we hypothesized, based on past observations of biological effect of warming, that mesopelagic species with southern distributions relative to southern California and Pacific sardine Sardinops sagax (a coastal pelagic species) would increase during the MHW while northern mesopelagics and northern anchovy Engraulis mordax (coastal pelagic) abundances would decline. Similar to past warming, southern mesopelagics increased and northern mesopelagics decreased. Unexpectedly, however, a common southern mesopelagic, Mexican lampfish Triphoturus mexicanus, was approximately three times more abundant than the previous annual high. Furthermore, whereas sardine abundance did not increase, larval anchovy abundance rose to near-record highs in summer 2016. Second, we hypothesized that fishes would spawn earlier during the MHW. Fishes did not spawn in an earlier season within a year, but five of six southern mesopelagic taxa spawned earlier than typical within winter and spring. Third, we predicted that species richness would increase moderately due to an influx of southern and exodus of northern species. Richness, however, was very high in all seasons and the highest ever during the summer as multiple species with primarily southern distributions were recorded spawning for the first time in southern California. The richness of northern species was also unexpectedly high during the MHW. Northern species likely persisted in the study area because in addition to the warm water, pockets of cold water were consistently present. If, as predicted, conditions similar to the MHW become more common as oceans warm, this unique and largely unexpected combination of fishes may reflect future biological conditions.

Phylogenomic analyses resolve relationships among garter snakes (Thamnophis: Natricinae: Colubridae) and elucidate biogeographic history and morphological evolution

Garter snakes (Thamnophis) are a successful group of natricines endemic to North America. They have become important natural models for ecological and evolutionary research, yet prior efforts to resolve phylogenetic relationships have resulted in conflicting topologies and weak support for certain relationships. Here, we use genomic data generated with a reduced representation double-digest RADseq approach to reassess evolutionary relationships across Thamnophis. We then use the resulting phylogeny to better understand how biogeography and feeding ecology have influenced lineage diversification and morphological evolution. We recovered highly congruent and strongly supported topologies from maximum likelihood and Bayesian analyses, but some discordance with a multispecies coalescent approach. All phylogenomic estimates split Thamnophis into two clades largely defined by northern and southern North American species. Divergence time estimates and biogeographic analyses indicate a mid-Miocene origin of Thamnophis in Mexico. In addition, historic vicariant events thought to explain biogeographic patterns in other lineages (e.g., Isthmus of Tehuantepec, Rocky Mountain Range, and Trans-Mexican Volcanic Belt) appear to have influenced patterns of diversification in Thamnophis as well. Analyses of morphological traits associated with feeding ecology showed moderate to strong phylogenetic signal. Nevertheless, phylogenetic ANOVA suggested significant differences in certain cranial morphologies between aquatic specialists and garter snakes that are terrestrial-aquatic generalists, independent of evolutionary history. Our new estimate of Thamnophis phylogeny yields an improved understanding of the biogeographic history and morphological evolution of garter snakes, and provides a robust framework for future research on these snakes.