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1. Synopsis of the Central Asian Salvia species with identification key

   https://doi.org/10.11646/phytotaxa.543.1.1  

   TURDIBOEV, OBIDJON A.; SHORMANOVA, AIJAMAL A.; SHELUDYAKOVA, MARIYA B.; AKBAROV, FERUZ; DREW, BRYAN T.; CELEP, FERHAT (April 2022, Phytotaxa)

   The genus Salvia is comprised of about 1000 species and has diversity hotspots in the Americas, East Asia, southwest Asia and the Mediterranean region. Central Asia also possesses considerable Salvia species diversity but is understudied relative to the aforementioned diversity hotspots. To help remedy this deficiency, we present a synopsis of Central Asian Salvia species based on extensive fieldwork, herbarium consultation, and literature surveys focusing on Uzbekistan, Kyrgyzstan, Tajikistan, Kazakhstan, and Turkmenistan (i.e., Central Asia). According to our final taxonomic revision, there are 41 species of native Salvia in the flora of Central Asia, 24 of which are endemic. Salvia ariana from Tajikistan and S. spinosa from Kazakhstan are documented from the respective countries for the first time, and the presence of S. tianschanica from Tajikistan and S. verticillata from Kazakhstan has been confirmed. In addition, the neotypification of S. deserta and three lectotypifications (Perovskia abrotanoides, S. bucharica and S. trautvetterii) are provided. Furthermore, we synonymized six species of Salvia that were previously reported from Central Asia, including S. intercedens, S. kopetdaghensis, S. linczevskii, S. lipskyi, S. semilanata and S. stepposa. Finally, a new species identification key for Central Asian Salvia is presented based on the new nomenclature changes and our taxonomic revision. 

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2. Spiranthes bightensis (Orchidaceae), a New and Rare Cryptic Hybrid Species Endemic to the U. S. Mid-Atlantic Coast

   https://doi.org/10.11646/phytotaxa.498.3.2  

   Pace, Matthew C. (April 2021, Phytotaxa)

   null (Ed.)

   Recognizing species diversity is challenging in genera that display interspecific similarity and intraspecific variation; hybridization and the evolution of cryptic hybrid species amplifies these challenges. Recent molecular and morphological research focused on the systematics of Spiranthes (Orchidaceae) support hybrid speciation as an important driver of species diversity, particularly within the S. cernua species complex. Working under an integrated history-bound phylogenetic species concept, new molecular and morphometric data provide evidence for a new and rare cryptic hybrid species resulting from the ancient hybridization of S. cernua × S. odorata, here described as S. bightensis. Although S. bightensis is regionally sympatric with S. cernua it does not co-occur with that species, and it is allopatric with respect to S. odorata. Endemic to a narrow region extending from the Delmarva Peninsula to Long Island, New York, this new species occurs in the shadow of the Northeast megalopolis and appears to have undergone a major population decline over the last 200 years. By recognizing this distinct evolutionary lineage as a new species, this research is the first step towards developing conservation protocols for this rare species and highlights the importance of the North American Geologic Coastal Plain for biodiversity conservation and evolution. 

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3. Persistence of a Geographically-Stable Hybrid Zone in Puerto Rican Dwarf Geckos

   https://doi.org/10.1093/jhered/esz015  

   Pinto, Brendan J; Titus-McQuillan, James; Daza, Juan D; Gamble, Tony (March 2019, Journal of Heredity)

   Abstract Determining the mechanisms that create and maintain biodiversity is a central question in ecology and evolution. Speciation is the process that creates biodiversity. Speciation is mediated by incompatibilities that lead to reproductive isolation between divergent populations and these incompatibilities can be observed in hybrid zones. Gecko lizards are a speciose clade possessing an impressive diversity of behavioral and morphological traits. In geckos, however, our understanding of the speciation process is negligible. To address this gap, we used genetic sequence data (both mitochondrial and nuclear markers) to revisit a putative hybrid zone between Sphaerodactylus nicholsi and Sphaerodactylus townsendi in Puerto Rico, initially described in 1984. First, we addressed discrepancies in the literature on the validity of both species. Second, we sampled a 10-km-wide transect across the putative hybrid zone and tested explicit predictions about its dynamics using cline models. Third, we investigated potential causes for the hybrid zone using species distribution modeling and simulations; namely, whether unique climatic variables within the hybrid zone might elicit selection for intermediate phenotypes. We find strong support for the species-level status of each species and no evidence of movement, or unique climatic variables near the hybrid zone. We suggest that this narrow hybrid zone is geographically stable and is maintained by a combination of dispersal and selection. Thus, this work has identified an extant model system within geckos that that can be used for future investigations detailing genetic mechanisms of reproductive isolation in an understudied vertebrate group. 

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4. Persistence of a Geographically-Stable Hybrid Zone in Puerto Rican Dwarf Geckos

   https://doi.org/doi.org/10.1093/jhered/esz015  

   Pinto, B. J.; Titus-McQuillan, J.; Daza, J. D.; Gamble, T. (January 2019, Journal of heredity)

   Determining the mechanisms that create and maintain biodiversity is a central question in ecology and evolution. Speciation is the process that creates biodiversity. Speciation is mediated by incompatibilities that lead to reproductive isolation between divergent populations and these incompatibilities can be observed in hybrid zones. Gecko lizards are a speciose clade possessing an impressive diversity of behavioral and morphological traits. In geckos, however, our understanding of the speciation process is negligible. To address this gap, we used genetic sequence data (both mitochondrial and nuclear markers) to revisit a putative hybrid zone between Sphaerodactylus nicholsi and Sphaerodactylus townsendi in Puerto Rico, initially described in 1984. First, we addressed discrepancies in the literature on the validity of both species. Second, we sampled a 10-km-wide transect across the putative hybrid zone and tested explicit predictions about its dynamics using cline models. Third, we investigated potential causes for the hybrid zone using species distribution modeling and simulations; namely, whether unique climatic variables within the hybrid zone might elicit selection for intermediate phenotypes. We find strong support for the species-level status of each species and no evidence of movement, or unique climatic variables near the hybrid zone. We suggest that this narrow hybrid zone is geographically stable and is maintained by a combination of dispersal and selection. Thus, this work has identified an extant model system within geckos that that can be used for future investigations detailing genetic mechanisms of reproductive isolation in an understudied vertebrate group. 

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5. Strong postmating reproductive isolation in Mimulus section Eunanus

   https://doi.org/10.1111/jeb.14219  

   Farnitano, Matthew C.; Sweigart, Andrea L. (October 2023, Journal of Evolutionary Biology)

   Abstract Postmating reproductive isolation can help maintain species boundaries when premating barriers to reproduction are incomplete. The strength and identity of postmating reproductive barriers are highly variable among diverging species, leading to questions about their genetic basis and evolutionary drivers. These questions have been tackled in model systems but are less often addressed with broader phylogenetic resolution. In this study we analyse patterns of genetic divergence alongside direct measures of postmating reproductive barriers in an overlooked group of sympatric species within the model monkeyflower genus, Mimulus. Within this Mimulus brevipes species group, we find substantial divergence among species, including a cryptic genetic lineage. However, rampant gene discordance and ancient signals of introgression suggest a complex history of divergence. In addition, we find multiple strong postmating barriers, including postmating prezygotic isolation, hybrid seed inviability and hybrid male sterility. M. brevipes and M. fremontii have substantial but incomplete postmating isolation. For all other tested species pairs, we find essentially complete postmating isolation. Hybrid seed inviability appears linked to differences in seed size, providing a window into possible developmental mechanisms underlying this reproductive barrier. While geographic proximity and incomplete mating isolation may have allowed gene flow within this group in the distant past, strong postmating reproductive barriers today have likely played a key role in preventing ongoing introgression. By producing foundational information about reproductive isolation and genomic divergence in this understudied group, we add new diversity and phylogenetic resolution to our understanding of the mechanisms of plant speciation. Abstract Hybrid seed inviability and other postmating reproductive barriers isolate species in Mimulus section Eunanus. Variation in seed size may help explain hybrid seed failure. Whole-genome sequencing indicates a complex history of divergence, including signals of ancient introgression and cryptic diversity. 

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