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1. Unveiling mesophotic diversity in Hawai‘i: two new species in the genera Halopeltis and Leptofauchea (Rhodymeniales, Rhodophyta)

   https://doi.org/10.4490/algae.2022.37.10.31  

   Alvarado, Erika A.; Cabrera, Feresa P.; Paiano, Monica O.; Fumo, James T.; Spalding, Heather L.; Smith, Celia M.; Leonard, Jason C.; Lopes Jr., Keolohilani H.; Kosaki, Randall K.; Sherwood, Alison R. (December 2022, Algae)

   Two genera of the Rhodymeniales, Halopeltis and Leptofauchea, are here reported for the first time from the Hawaiian Islands and represent the deepest records for both genera. Molecular phylogenetic analyses of cytochrome oxidase subunit I (COI), rbcL, and large subunit ribosomal DNA (LSU) sequences for Hawaiian specimens of Leptofauchea revealed one well-supported clade of Hawaiian specimens and three additional lineages. One of these clades is described here as Leptofauchea huawelau sp. nov., and is thus far known only from mesophotic depths at Penguin Bank in the Main Hawaiian Islands. L. huawelau sp. nov. is up to 21 cm, and is the largest known species. An additional lineage identified in the LSU and rbcL analyses corresponds to the recently described L. lucida from Western Australia, and is a new record for Hawai‘i. Hawaiian Halopeltis formed a well-supported clade along with H. adnata from Korea, the recently described H. tanakae from mesophotic depths in Japan, and H. willisii from North Carolina, and is here described as Halopeltis nuahilihilia sp. nov. H. nuahilihilia sp. nov. has a distinctive morphology of narrow vegetative axes that harbor constrictions along their length. The current distribution of H. nuahilihilia includes mesophotic depths around W. Maui, W. Moloka‘i, and the island of Hawai‘i in the Main Hawaiian Islands. Few reproductive characters were observed because of the small number of specimens available; however, both species are distinct based on phylogeny and morphology. These descriptions further emphasize the Hawaiian mesophotic zone as a location harboring many undescribed species of marine macroalgae. 

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2. Species delimitation, biogeography, and natural history of dwarf funnel web spiders (Mygalomorphae, Hexurellidae, Hexurella) from the United States / Mexico borderlands

   https://doi.org/10.3897/zookeys.1167.103463  

   Monjaraz-Ruedas, Rodrigo; Mendez, Raymond Wyatt; Hedin, Marshal (June 2023, ZooKeys)

   The rarely encountered spider genusHexurellaGertsch & Platnick, 1979 includes some of the smallest mygalomorph spiders in the world, with four poorly known taxa from central and southeastern montane Arizona, southern California, and northern Baja California Norte. At time of description the genus was known from fewer than 20 individuals, with sparse natural history information suggesting a vagrant, web-building, litter-dwelling natural history. Here the first published taxonomic and natural history information for this taxon is provided in more than 50 years, working from extensive new geographic sampling, consideration of male and female morphology, and sequence capture-based nuclear phylogenomics and mitogenomics. Several new species are easily diagnosed based on distinctive male morphologies, while a complex of populations from central and northern Arizona required an integrative combination of genomic algorithmic species delimitation analyses and morphological study. Four new species are described, includingH. ephedrasp. nov.,H. uwiiltilsp. nov.,H. xericasp. nov., andH. zassp. nov.Females ofH. encinaGertsch & Platnick, 1979 are also described for the first time. It is predicted that additional new species will ultimately be found in the mountains of central and northwestern Arizona, northern mainland Mexico, and the Mojave Desert of California. 

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3. Comparison between p‐distance and single‐locus species delimitation models for delineating reproductively tested strains of pennate diatoms (Bacillariophyceae) using cox 1, rbcL and ITS

   https://doi.org/10.1111/jeu.12986  

   Franco, Andréa de; Ashworth, Matt P.; Odebrecht, Clarisse (September 2023, Journal of Eukaryotic Microbiology)

   Abstract Several automated molecular methods have emerged for distinguishing eukaryote species based on DNA sequence data. However, there are knowledge gaps around which of these single‐locus methods is more accurate for the identification of microalgal species, such as the highly diverse and ecologically relevant diatoms. We applied genetic divergence, Automatic Barcode Gap Discovery for primary species delimitation (ABGD), Assemble Species by Automatic Partitioning (ASAP), Statistical Parsimony Network Analysis (SPNA), Generalized Mixed Yule Coalescent (GMYC) and Poisson Tree Processes (PTP) using partialcox1,rbcL,5.8S + ITS2,ITS1 + 5.8S + ITS2 markers to delineate species and compare to published polyphasic identification data (morphological features, phylogeny and sexual reproductive isolation) to test the resolution of these methods. ASAP, ABGD, SPNA and PTP models resolved species ofEunotia,Seminavis, Nitzschia, SellaphoraandPseudo‐nitzschiacorresponding to previous polyphasic identification, including reproductive isolation studies. In most cases, these models identified diatom species in similar ways, regardless of sequence fragment length. GMYC model presented smallest number of results that agreed with previous published identification. Following the recommendations for proper use of each model presented in the present study, these models can be useful tools to identify cryptic or closely related species of diatoms, even when the datasets have relatively few sequences. 

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4. Astronomical Cardiology: A Search For Heartbeat Stars Using $\text{Gaia}$ and $\text{TESS}$

   https://doi.org/10.33232/001c.142226  

   Callahan, Jowen; Rowan, D M; Kochanek, C S; Stanek, K Z (January 2025, The Open Journal of Astrophysics)

   Heartbeat stars are a subclass of binary stars with short periods, high eccentricities, and phase-folded light curves that resemble an electrocardiogram. We start from the $\text{𝐺𝑎𝑖𝑎}$catalogs of spectroscopic binaries and use $\text{𝑇𝐸𝑆𝑆}$photometry to identify 112 new heartbeat star systems. We fit their phase-folded light curves with an analytic model to measure their orbital periods, eccentricities, inclinations, and arguments of periastron. We then compare these orbital parameters to the $\text{𝐺𝑎𝑖𝑎}$spectroscopic orbital solution. Our periods and eccentricities are consistent with the $\text{𝐺𝑎𝑖𝑎}$solutions for 85 $\%$of the single-line spectroscopic binaries but only 20 $\%$of the double-line spectroscopic binaries. For the two double-line spectroscopic binary heartbeat stars with consistent orbits, we combine the $\text{𝑇𝐸𝑆𝑆}$phase-folded light curve and the $\text{𝐺𝑎𝑖𝑎}$velocity semi-amplitudes to measure the stellar masses and radii with $\text{𝙿𝙷𝙾𝙴𝙱𝙴}$. In a statistical analysis of the HB population, we find that non-giant heartbeat stars have evolved off the main sequence and that their fractional abundance rises rapidly with effective temperature. 

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5. Stemflow dissolved organic matter in mixed temperate forests: temporal and interspecific variation of optical indices and development of a stemflow-specific PARAFAC model

   https://doi.org/10.1007/s10533-024-01158-8  

   O’Halloran, Robyn_C; Guerard, Jennifer_J; Levia, Delphis_F (June 2024, Biogeochemistry)

   Abstract Stemflow is a conduit for the transport of canopy-derived dissolved organic matter (DOM) to the forest floor. This study examined the character of stemflow DOM for four tree species over four phenophases (leafless, emergence, leafed, and senescence for deciduous species and leafed-winter, emergence, leafed- spring/summer, and senescence for coniferous species) occurring in temperate forests; namely,Betula lentaL. (sweet birch),Fagus grandifoliaEhrh. (American beech),Liriodendron tulipiferaL. (yellow poplar), andPinus rigidaMill. (pitch pine). American beech exhibited the lowest average specific UV absorbance at 254 nm (SUVA₂₅₄) values, while yellow poplar displayed the highest values. SUVA₂₅₄values were largest in senescence and smallest in emergence. The spectral slope ratio was lower for pitch pine than the deciduous tree species. Humification index (HIX) values decreased across all species during the emergence phenophase. The developed and validated stemflow-specific four-component parallel factor analysis (PARAFAC) model demonstrated the combined influence of interspecific and temporal fluctuations on the composition of humic and protein-like substances within stemflow. By separating and examining stemflow DOM independent of throughfall, our study provides fresh insights into the spatiotemporal dynamics of stemflow inputs to near-trunk soils that may inform hot spots and hot moments theories. 

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