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1. Allopolyploid origin and diversification of the Hawaiian endemic mints

   https://doi.org/10.1038/s41467-024-47247-y  

   Tomlin, Crystal_M; Rajaraman, Sitaram; Sebesta, Jeanne_Theresa; Scheen, Anne-Cathrine; Bendiksby, Mika; Low, Yee_Wen; Salojärvi, Jarkko; Michael, Todd_P; Albert, Victor_A; Lindqvist, Charlotte (April 2024, Nature Communications)

   Abstract Island systems provide important contexts for studying processes underlying lineage migration, species diversification, and organismal extinction. The Hawaiian endemic mints (Lamiaceae family) are the second largest plant radiation on the isolated Hawaiian Islands. We generated a chromosome-scale reference genome for one Hawaiian species,Stenogyne calaminthoides, and resequenced 45 relatives, representing 34 species, to uncover the continental origins of this group and their subsequent diversification. We further resequenced 109 individuals of twoStenogynespecies, and their purported hybrids, found high on the Mauna Kea volcano on the island of Hawai’i. The three distinct Hawaiian genera,Haplostachys,Phyllostegia, andStenogyne, are nested inside a fourth genus,Stachys. We uncovered four independent polyploidy events withinStachys, including one allopolyploidy event underlying the Hawaiian mints and their direct western North American ancestors. While the Hawaiian taxa may have principally diversified by parapatry and drift in small and fragmented populations, localized admixture may have played an important role early in lineage diversification. Our genomic analyses provide a view into how organisms may have radiated on isolated island chains, settings that provided one of the principal natural laboratories for Darwin’s thinking about the evolutionary process. 

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2. Two new endemic species of blueberry (Vaccinium L., Ericaceae) from Luzon and Mindanao islands, Philippines

   https://doi.org/10.11646/phytotaxa.564.2.1  

   TAMAYO, MAVERICK N.; FRITSCH, PETER W. (September 2022, Phytotaxa)

   Two new species of Vaccinium from the Philippines are described and illustrated from historical herbarium collections. Vaccinium burburan from Luzon Island, Northern Philippines is morphologically similar to V. tenuipes, but is distinguished by having shorter petioles, pedicels and corolla, adaxially pubescent leaf blades with cordate base, apically pubescent corollas, and pubescent filaments throughout. It is only one of two species of Vaccinium in the Philippines known to have a cordate leaf blade base. Vaccinium burburan is considered critically endangered. Vaccinium jubatum from Mindanao Island, Southern Philippines, is morphologically similar to V. sylvaticum, but is distinguished by having a dentate leaf blade margin, shorter inflorescences and pedicels, a glabrous calyx, and shorter filaments. The dentate leaf blade margin of V. jubatum uniquely distinguishes it from other Philippine Vaccinium species. The conservation status of V. jubatum is considered data deficient. These discoveries further increase the current number of known Vaccinium species in the Philippines to 40. 

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3. Skull evolution and lineage diversification in endemic Malagasy carnivorans

   https://doi.org/10.1098/rsos.240538  

   Law, Chris J; Linden, Tate J; Flynn, John J (October 2024, Royal Society Open Science)

   Madagascar is one of the world’s foremost biodiversity hotspots with more than 90% of its species endemic to the island. Malagasy carnivorans are one of only four extant terrestrial mammalian clades endemic to Madagascar. Although there are only eight extant species, these carnivorans exhibit remarkable phenotypic and ecological diversity that is often hypothesized to have diversified through an adaptive radiation. Here, we investigated the evolution of skull diversity in Malagasy carnivorans and tested if they exhibited characteristics of convergence and an adaptive radiation. We found that their skull disparity exceeds that of any other feliform family, as their skulls vary widely and strikingly capture a large amount of the morphological variation found across all feliforms. We also found evidence of shared adaptive zones in cranial shape between euplerid subclades and felids, herpestids and viverrids. Lastly, contrary to predictions of adaptive radiation, we found that Malagasy carnivorans do not exhibit rapid lineage diversification and only marginally faster rates of mandibular shape evolution and to a lesser extent cranial shape evolution, compared to other feliforms. These results reveal that exceptional diversification rates are not necessary to generate the striking phenotypic diversity that evolved in carnivorans after their dispersal to and isolation on Madagascar. 

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4. Ecological diversification reveals routes of pathogen emergence in endemic Vibrio vulnificus populations

   https://doi.org/10.1073/pnas.2103470118  

   López-Pérez, M; Jayakumar, JM; Grant, TA; Zaragoza-Solas, A; Cabello-Yeves, PJ; Almagro-Moreno, S (January 2021, Proceedings of the National Academy of Sciences of the United States of America)

   Pathogen emergence is a complex phenomenon that, despite its public health relevance, remains poorly understood. Vibrio vulnificus, an emergent human pathogen, can cause a deadly septicaemia with over 50% mortality rate. To date, the ecological drivers that lead to the emergence of clinical strains and the unique genetic traits that allow these clones to colonize the human host remain mostly unknown. We recently surveyed a large estuary in eastern Florida, where outbreaks of the disease frequently occur, and found endemic populations of the bacterium. We established two sampling sites and observed strong correlations between location and pathogenic potential. One site is significantly enriched with strains that belong to one phylogenomic cluster (C1) from which the majority of clinical strains belong to. Interestingly, strains isolated from this site exhibit phenotypic traits associated with clinical outcomes, whereas strains from the second site belong to a cluster that rarely causes disease in humans (C2). Analyses of C1 genomes indicate unique genetic markers in the form of clinical-associated alleles with potential role in virulence. Finally, metagenomic and physicochemical analyses of the sampling sites indicate that this marked cluster distribution and genetic traits are strongly associated with distinct biotic and abiotic factors (e.g. salinity, nutrients, or biodiversity), revealing how ecosystems generate selective pressures that facilitate the emergence of specific strains with pathogenic potential in a population. This knowledge can be applied to assess the risk of pathogen emergence from environmental sources, and integrated towards the development of novel strategies for the prevention of future outbreaks. 

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5. Molecular phylogenetic estimates of evolutionary affinities and the first reports of phenotypic variation in two secretive, endemic reptiles from the Romblon Island Group, central Philippines) from Luzon Island, the Philippines

   https://doi.org/10.26757/pjsb2020b14002  

   Meneses, C.G. (January 2020, Philippine Journal of Systematic Biology)

   null (Ed.)

   We report on the first molecular estimates of phylogenetic relationships of Brachymeles dalawangdaliri (Scincidae) and Pseudogekko isapa (Gekkonidae), and present new data on phenotypic variation in these two poorly known taxa, endemic to the Romblon Island Group of the central Philippines. Because both species were recently described on the basis of few, relatively older, museum specimens collected in the early 1970s (when preservation of genetic material was not yet standard practice in biodiversity field inventories), neither taxon has ever been included in modern molecular phylogenetic analyses. Likewise, because the original type series for each species consisted of only a few specimens, biologists have been unable to assess standard morphological variation in either taxon, or statistically assess the importance of characters contributing to their diagnoses and identification. Here we ameliorate both historical shortfalls. First, our new genetic data allowed us to perform novel molecular phylogenetic analyses aimed at elucidating the evolutionary relationships of these lineages; secondly, with population level phenotypic data, from the first statistical sample collected for either species, and including adults of both sexes. We reaffirm the distinctiveness of both named taxa as valid species, amend their diagnoses to facilitate the recognition of both, distinguish them from congeners, and consider the biogeographic affinities of both lineages. Our contribution emphasizes the conservation significance of Sibuyan Island’s Mt. Guiting-Guiting Natural Park, the diverse, idiosyncratic biogeographic histories of its variably-assembled, highly endemic reptile fauna, and the critical importance of multiple, repeated, survey–resurvey studies for understanding forest community species composition and the evolutionary history of Philippine biodiversity. 

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