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1. Evolutionary innovation accelerates morphological diversification in pufferfishes and their relatives

   https://doi.org/10.1093/evolut/qpae127  

   Troyer, Emily M; Evans, Kory M; Goatley, Christopher_H R; Friedman, Matt; Carnevale, Giorgio; Nicholas, Benjamin; Kolmann, Matthew; Bemis, Katherine E; Arcila, Dahiana (September 2024, Evolution)

   Sherratt, Emma; Morlon, Hélène (Ed.)

   Abstract Evolutionary innovations have played an important role in shaping the diversity of life on Earth. However, how these innovations arise and their downstream effects on patterns of morphological diversification remain poorly understood. Here, we examine the impact of evolutionary innovation on trait diversification in tetraodontiform fishes (pufferfishes, boxfishes, ocean sunfishes, and allies). This order provides an ideal model system for studying morphological diversification owing to their range of habitats and divergent morphologies, including the fusion of the teeth into a beak in several families. Using three-dimensional geometric morphometric data for 176 extant and fossil species, we examine the effect of skull integration and novel habitat association on the evolution of innovation. Strong integration may be a requirement for rapid trait evolution and facilitating the evolution of innovative structures, like the tetraodontiform beak. Our results show that the beak arose in the presence of highly conserved patterns of integration across the skull, suggesting that integration did not limit the range of available phenotypes to tetraodontiforms. Furthermore, we find that beaks have allowed tetraodontiforms to diversify into novel ecological niches, irrespective of habitat. Our results suggest that general rules pertaining to evolutionary innovation may be more nuanced than previously thought. 

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2. Rampant convergent evolution of vascular oddities and a synnovation characterize the rapid radiation of Paullinieae lianas

   https://doi.org/10.1101/2025.07.12.664521  

   Cunha_Neto, Israel L; Kozma, Zachary; Lichter-Marck, Isaac H; Acevedo-Rodríguez, Pedro; Onyenedum, Joyce G (July 2025, bioRxiv)

   Abstract Climbing plants have independently evolved thousands of times and are particularly successful in tropical forests, yet their anatomical and evolutionary distinctiveness remains poorly understood. Among the most striking innovations in woody climbers—or “lianas”—are vascular variants: modifications to xylem and phloem that depart from the typical growth found in trees and shrubs. In this work, we leverage the fourth largest lineage of neotropical lianas, Paullinieae (Sapindaceae), to elucidate the evolution of development of vascular variants, and to test key innovation hypotheses in this megadiverse group. We reconstruct the largest phylogeny of any liana lineage to date (227 species, 351 nuclear genes), revealing a rapid radiation in the Miocene. Our anatomical evaluation of 462 species uncovered six patterns of vascular variants spanning three developmental categories—procambial, cambial, and ectopic cambia—which evolved repeatedly across the tree. Using stochastic mapping and a developmental complexity framework, we show that evolutionary transitions from typical growth disproportionately favored developmentally simple variants, suggesting that developmental accessibility constrains macroevolutionary trajectories. Despite the temporal overlap between the disparification of vascular variants, and the diversification rate shift, we find no evidence that vascular variants alone drive species diversification. Instead, diversification rates correlate with the presence of tendrils, climbing growth forms, and zygomorphic flowers. These results suggest a synnovation— a suite of synergistic innovations rather than a single trait—as the driver of lineage radiation in Paullinieae. Our study highlights how integrating phylogenomics, developmental anatomy, and trait evolution can illuminate the evolutionary mechanisms shaping plant diversity. Significance StatementLianas are functionally distinct from trees and are rising in abundance across neotropical forests. Yet, it remains poorly understood how these plants are developmentally constructed, and what traits underlie their success. Here, we present the largest molecular phylogeny of any climbing plant lineage and show that vascular variants—unusual stem anatomies that enhance flexibility— are remarkably diverse and have evolved repeatedly in Paullinieae. However, these striking modifications are not linked to species diversification. Instead, we find that the combination of three traits—the climbing habit, coiling tendrils, and zygomorphic flowers—collectively drove the diversification of Paullinieae. Our findings challenge traditional views of key innovations, showing that synergistic trait combinations, rather than any single trait, can catalyze evolutionary radiations and shape biodiversity. 

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3. Has past climate change affected cold-specialized species differentially through space and time?

   https://doi.org/10.1111/syen.12341  

   Schoville, S.D.; Bougie, T.A.; Dudko, R.Y.; Medeiros, M.J. (January 2019, Systematic entomology)

   Quaternary climate change has been strongly linked to distributional shifts and recent species diversification. Montane species, in particular, have experienced enhanced isolation and rapid genetic divergence during glacial fluctuations, and these processes have resulted in a disproportionate number of neo-endemic species forming in high elevation habitats. In temperate montane environments, a general model of alpine population history is well supported, where cold-specialized species track favorable climate conditions downslope during glacial episodes and upslope during warmer interglacial periods, which leads to a climate-driven population or species diversification pump. However, it remains unclear how geography mediates distributional changes and whether certain episodes of glacial history have differentially impacted rates of diversification. We address these questions by examining phylogenomic data in a North American clade of flightless, cold-specialized insects, the ice crawlers (Insecta: Grylloblattodea: Grylloblattidae: Grylloblatta). These low vagility organisms have the potential to reveal highly localized refugia and patterns of spatial recolonization, as well as a longer history of in situ diversification. Using continuous phylogeographic analysis of species groups, we show that all species tend to retreat to nearby low elevation habitats across western North America during episodes of glaciation, but species at high latitude exhibit larger distributional shifts. Lineage diversification was examined over the course of the Neogene and Quaternary periods, with statistical analysis supporting a direct association between climate variation and diversification rate. Major increases in lineage diversification appear correlated to warm and dry periods, rather than extreme glacial events. Finally, we identify substantial cryptic diversity among ice crawlers, leading to high endemism across their range. This diversity provides new insights into highly localized glacial refugia for cold-specialized species across western North America. 

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4. The Sequential Direct and Indirect Effects of Mountain Uplift, Climatic Niche, and Floral Trait Evolution on Diversification Dynamics in an Andean Plant Clade

   https://doi.org/10.1093/sysbio/syae011  

   Dellinger, Agnes S; Lagomarsino, Laura; Michelangeli, Fabián; Dullinger, Stefan; Smith, Stacey D (March 2024, Systematic Biology)

   Särkinen, Tiina (Ed.)

   Abstract Why and how organismal lineages radiate is commonly studied through either assessing abiotic factors (biogeography, geomorphological processes, and climate) or biotic factors (traits and interactions). Despite increasing awareness that both abiotic and biotic processes may have important joint effects on diversification dynamics, few attempts have been made to quantify the relative importance and timing of these factors, and their potentially interlinked direct and indirect effects, on lineage diversification. We here combine assessments of historical biogeography, geomorphology, climatic niche, vegetative, and floral trait evolution to test whether these factors jointly, or in isolation, explain diversification dynamics of a Neotropical plant clade (Merianieae, Melastomataceae). After estimating ancestral areas and the changes in niche and trait disparity over time, we employ Phylogenetic Path Analyses as a synthesis tool to test eleven hypotheses on the individual direct and indirect effects of these factors on diversification rates. We find strongest support for interlinked effects of colonization of the uplifting Andes during the mid-Miocene and rapid abiotic climatic niche evolution in explaining a burst in diversification rate in Merianieae. Within Andean habitats, later increases in floral disparity allowed for the exploitation of wider pollination niches (i.e., shifts from bee to vertebrate pollinators), but did not affect diversification rates. Our approach of including both vegetative and floral trait evolution, rare in assessments of plant diversification in general, highlights that the evolution of woody habit and larger flowers preceded the colonization of the Andes, but was likely critical in enabling the rapid radiation in montane environments. Overall, and in concert with the idea that ecological opportunity is a key element of evolutionary radiations, our results suggest that a combination of rapid niche evolution and trait shifts was critical for the exploitation of newly available niche space in the Andes in the mid-Miocene. Further, our results emphasize the importance of incorporating both abiotic and biotic factors into the same analytical framework if we aim to quantify the relative and interlinked effects of these processes on diversification. 

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5. Adaptive radiation despite conserved modularity patterns in San Salvador Island Cyprinodon pupfishes and their hybrids

   https://doi.org/10.1093/evolinnean/kzae013  

   Chan, HoWan; Colaco, Emma; Martin, Christopher H; Evans, Kory M (January 2024, Evolutionary Journal of the Linnean Society)

   Abstract Adaptive radiations are striking examples of rapid speciation along ecological lines. In adaptive radiations, fast rates of lineage diversification often pair with rapid rates of morphological diversification. Such diversification has often been documented through the lens of ecological drivers, overlooking the intrinsic structural constraints that may also have a key role in configuring patterns of trait diversification. Covariation within and between traits has been hypothesized to govern the axes of trait evolution, either by increasing the degree of covariation between traits (i.e. integration), which promotes morphological coordination, or by strengthening the degree of covariation within traits (i.e. modularity), which allows organisms to explore novel trait combinations and different regions of morphospace. Here, we study the modularity of the skull within an adaptive radiation of pupfishes that is endemic to San Salvador Island, Bahamas. This radiation exhibits divergent craniofacial morphologies, including generalist, snail-eating specialist, and scale-eating specialist species. We assessed morphological disparity, integration strength, and modularity patterns across the sympatric San Salvador Island pupfish radiation, lab-reared hybrids, and closely related outgroup species. Our findings revealed an unexpected uniformity in the pattern of modularity across diverse species, supporting a five-module functional hypothesis comprising the oral jaw, pharyngeal jaw, neurocranium, hyoid apparatus, and hyomandibula. Despite this conserved modularity pattern, all species exhibited weak but significantly varying strengths of overall between-module integration and significant disparity across all cranial regions. Our results suggest rapid morphological diversification can occur even with conserved patterns of modularity. We propose that broadscale patterns of modularity are more conserved while between-module associations are more evolvable between species. 

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