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Zoological Journal of the Linnean Society

Oxford University Press (OUP)

Preprints posted in the last 30 days, ranked by how well they match Zoological Journal of the Linnean Society's content profile, based on 14 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

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Reassessing display behavior from Bels et al. (2025) given the complexity of anthropogenic hybridization and intraspecific diversity in Iguana iguana

van den Burg, M. P.; Thibaudier, J.

2026-03-23 zoology 10.64898/2026.03.19.713079 medRxiv
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Understanding behavioral differences between non-native and closely related endangered species could be important to aid conservation management. In volume 169 of Zoology, Bels et al. (2025) reported on their comparison of display-action-patterns (DAP) between native Iguana delicatissima and non-native iguanas present on islands of the Guadeloupe Archipelago in the Caribbean Lesser Antilles. Here, we address conceptual and methodological concerns about their work and reanalyze their data given our proposed corrections, primarily a literature-informed adjustment of their "species" category. We additionally utilize online videos from South American mainland I. iguana populations, from where the non-native iguanas in the Guadeloupe Archipelago originate, to better understand the different DAPs between native and non-native iguanas in the Guadeloupe Archipelago. Significant differences in DAP characteristics among "species" categories (native I. delicatissima, non-native iguanas, and hybrids) show that Bels et al. (2025) oversimplified their data analyses by merging all non-native populations into one group. This result indicates the presence of behavioral variation among subpopulations within widely hybridizing iguanid populations, which has been poorly studied. Additionally, videos from mainland populations across two major mitochondrial clades of Iguana iguana show that non-native iguanas on Guadeloupe retained DAP characteristics of those populations from which they originate. We discuss these findings in light of the proposed hypotheses put forward by Bels et al. (2025), of which two can be excluded. Overall, our reanalysis shows that studies focusing on characteristics within settings of complex hybridization in diverse species should acknowledge this complexity.

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Cryptic diversity in Astyanax (Characiformes: Acestrorhamphidae) from the Magdalena basin, Colombia: Insights from molecular and morphometric evidence

Marquez, E. J.; Garcia-Castro, K. L.; Alvarez, D. R.; DoNascimiento, C.

2026-03-31 genetics 10.64898/2026.03.28.714954 medRxiv
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Astyanax Baird & Girard, 1854 is a widely distributed and species-rich genus of Acestrorhamphidae, whose abundant populations in Neotropical basins play a crucial ecological role at the trophic level. Taxonomic uncertainties persist within the genus, as seen in Astyanax sp. (formerly designated as A. fasciatus) from the Magdalena basin in Colombia. Concerns about its genetic status are heightened due to ecological threats posed by hydroelectric dams, from habitat loss to river connectivity. We isolated and characterized 17 microsatellite loci to assess the population genetics of this species in a broad sample from the middle and lower sections of the Cauca River, now interrupted by the Ituango dam. Furthermore, a multidisciplinary approach integrating phylogenetic analyses of mitochondrial (COI) and nuclear (rag2) markers with geometric morphometric analyses was employed to evaluate potential cryptic diversity within Astyanax sp. Microsatellites revealed two genetic groups in the studied area, strongly supported as distinct lineages by phylogenetic analyses. Unexpectedly, one of these lineages of Astyanax sp. was recovered in an unresolved clade with samples of A. microlepis and allopatric samples of A. viejita from the Maracaibo Lake basin. Each genetic group showed high genetic diversity, but also evidence of recent bottleneck events and significant-high values of inbreeding. Morphometric analyses provided evidence of significant phenotypic differentiation among A. microlepis, Astyanax sp. 1 (Asp1), and Astyanax sp. 2 (Asp2). Morphological patterns ranged from the robust profile of A. microlepis to the streamlined shape of Astyanax sp. 2 (Asp2), with Astyanax sp. 1 (Asp1) displaying intermediate traits and localized differences in head length and fin placement. Statistical support from permutation tests and a high overall classification accuracy (95.65%) underscore the existence of distinct morphospecies, suggesting that phenotypic differentiation is well-established, despite the complex evolutionary history of the group. This study suggests the presence of cryptic diversity within Astyanax sp. and provides valuable genetic information for the conservation and management of their populations in the Magdalena basin.

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Transcriptomes resolve phylogenetic relationships and reveal undescribed diversity in taildropper slugs (Genus Prophysaon)

Smith, M. L.; Moshier, S.; Shoobs, N. F.

2026-03-27 evolutionary biology 10.64898/2026.03.25.713997 medRxiv
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The temperate rainforests of the Pacific Northwest of North America harbor many endemic taxa whose evolutionary histories have been shaped by major climatic and geologic events. The enigmatic taildropper slugs (genus Prophysaon) are one example, notable for their ability to autonomize their tails to escape predators. Despite extensive work uncovering the evolutionary history of individual lineages, relationships among the nine recognized species of Prophysaon remain poorly understood due to insufficient molecular data. To address this, we collected transcriptomes for six of the nine currently accepted species of Prophysaon. Using these data, we were able to resolve species relationships, calling into question the existing subgeneric classification based on morphology. We also detected undescribed phenotypic diversity within the P. andersonii--P. foliolatum species complex, with molecular data supporting the distinctness of two phenotypically distinct populations from Washington. Finally, our transcriptomic data suggest a moderate role of introgression in shaping the evolutionary history of Prophysaon. Here, we synonymize the subgenus Mimetarion with nominotypical Prophysaon. Future work should further investigate whether the undescribed diversity detected here represents species level differentiation.

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Body size, dental pathology and maternal genetic diversity of ancient horses in the eastern Baltic Sea region and western Russia

Honka, J.; Salazar, D.; Askeyev, A. O.; Askeyev, I. V.; Askeyev, O. V.; Aspi, J.; Asylgaraeva, G. S.; Niskanen, M.; Mannermaa, K.; Olli, S.; Piipponen, N.; Piliciauskiene, G.; Shaymuratova, D. N.; Valiev, R. R.; Kvist, L.

2026-03-19 genetics 10.64898/2026.03.17.712305 medRxiv
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The early evolutionary history of modern domestic horses (Equus caballus/E. ferus caballus), known as the DOM2 lineage, is well documented due to numerous archaeological and ancient DNA (aDNA) studies. Although many uncertainties remain in the domestication timeline, current evidence suggests that the domestication of modern horses began in the Pontic-Caspian steppe at least [~]2700 BCE (before common era), or even earlier. However, it is not known how long remnant wild horse populations survived or when domestic horses were introduced into Northern Europe. In this study, we review the current knowledge of horse domestication, focusing on Northern Europe. We analysed prehistoric horses from western Russia to assess the body sizes of wild horses from the Ivanovskaya site (5900-3800 BCE) in the Pontic-Caspian steppe, and the body weight of one Lithuanian wild horse (4000-3800 BCE). Additionally, we analysed body sizes of Late Bronze Age-Early Roman Age horses (1100 BCE-300 CE; common era) and re-analysed body sizes and estimated rider weights of historic domestic horses from Lithuania (100-1400 CE). We searched for pathological changes and signs of bit wear indicative of bridling. Furthermore, we investigated maternal genetic diversity by sequencing ancient mitochondrial DNA. We found that wild horses from Ivanovskaya were intermediate in body size between earlier and more recent horses of the Eurasian Steppe, and that the Lithuanian wild horse weighed only [~]270 kg and Late Bronze Age-Early Roman Age horses 200-300 kg. Lithuanian domestic horses were pony-sized (< 130 cm on average). Bit wear was confirmed on one tooth, the oldest domestic horse in Lithuania (799-570 cal BCE). Another tooth showed signs of the Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) condition. Mitochondrial DNA was successfully amplified from one Ivanovskaya wild horse along with 25 other ancient samples, including Lithuanias oldest domestic horse. mtDNA diversity was high, revealing several maternal lineages.

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New insights into the postcranial morphology of Lithornis vulturinus from the Eocene London Clay

Widrig, K.; Field, D. J.

2026-03-19 paleontology 10.64898/2026.03.17.711321 medRxiv
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The deepest phylogenetic divergence within crown birds (Neornithes) is that between the reciprocally monophyletic Palaeognathae and Neognathae. Extant palaeognath diversity comprises the iconic flightless "ratites" (ostriches, rhea, kiwi, cassowaries, and emu), as well as 46 species of volant tinamous in Central and South America (Billerman et al., 2020). Although the earliest stages of palaeognath evolution remain shrouded in mystery due to a sparse fossil record, a group of apparently volant extinct palaeognaths from the Paleogene of Europe and North America, the lithornithids, can help to clarify palaeognath origins. Here, we use high resolution microCT scanning to characterize the morphology of two lithornithid specimens from the early Eocene (Ypresian) London Clay Formation: the neotype of Lithornis vulturinus (NHMUK A5204), from the Isle of Sheppey, Kent, England, and a newly discovered clay nodule containing lithornithid postcranial remains from the nearby locality of Seasalter. This three-dimensional dataset reveals bones from the L. vulturinus neotype that are partially or completely covered by matrix, allowing us to redescribe this critical specimen in new detail and present a revised differential diagnosis of L. vulturinus. We refer the new specimen from Seasalter to L. vulturinus on the basis of apomorphies such as a proximally directed lateral process of the coracoid, caudally divergent lateral margins of the sternum, an arcuate deltopectoral crest, as well as its provenance from a nearby penecontemporaneous locality. The Seasalter specimen contains abundant postcranial material that provides new insight into bones damaged or missing in the neotype, including two undamaged scapulae bearing the hooked acromion that is a diagnostic feature of lithornithids, two complete coracoids, and a nearly complete three-dimensionally preserved sternum. Its estimated body mass is one third larger than that of the neotype, indicating intraspecific variation within L. vulturinus that may reflect sexual dimorphism. Molecular divergence dates and Cretaceous neognath fossils indicate the presence of total-clade palaeognaths before the K-Pg mass extinction event; detailed anatomical descriptions of Paleogene palaeognaths will assist in the identification of the first total-clade palaeognaths from the Cretaceous, and provide insight into how and when flight was independently lost among Cenozoic crown palaeognaths.

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Ghostbusting the national bird checklist: integrative evidence shows that Pionus fuscus does not occur in Colombia

Carrillo-Restrepo, J. C.; Velasquez-Tibata, J.

2026-03-26 ecology 10.64898/2026.03.23.713821 medRxiv
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Natural history collections underpin our understanding of species distributions, yet some historical records remain embedded in modern avifaunal checklists despite limited documentation and no independent verification. One such case concerns the Dusky Parrot Pionus fuscus in Colombia: although reported from specimens collected by Melbourne A. Carriker Jr. in 1942 in the Serrania de Perija, the species has not been observed in the country for nearly eight decades yet continues to be included in national checklists and conservation assessments. We reassessed the validity of this record by applying a multi-evidence framework integrating historic archival reconstruction, specimen-based morphological comparisons, climatic niche analyses, biogeographic limit assessment and contemporary survey-effort data. Historical documentation and morphological evidence based on high-resolution specimen images and associated curatorial records demonstrate that the Carriker specimens correspond to Pionus chalcopterus, not P. fuscus. Climatic niche analyses reveal minimal environmental overlap between P. chalcopterus and P. fuscus, and place the Perija locality within the climatic niche of P. chalcopterus, while regional biogeography and extensive modern birdwatching coverage provide no support for the occurrence of P. fuscus in Perija. Together, these concordant lines of evidence demonstrate that P. fuscus does not occur in Colombia. Our findings support its removal from national bird lists and conservation assessments and highlight how integrated, multi-evidence reassessments of historical records strengthen ornithological baselines, improve biogeographic inference and ensure that conservation priorities rest on verifiable evidence.

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Contrasting Species-Level and Genus Level Disparity Patterns within the ammonoid family Acanthoceratidae

Howard, L.; Wagner, P. J.

2026-03-23 paleontology 10.64898/2026.03.20.713222 medRxiv
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Paleobiologists commonly use genera as a proxy for species in biodiversity studies. However, a lingering concern is that patterns among genera might not always faithfully reflect patterns among species. To date, the concern has focused chiefly on measured patterns of richness over time and on implied origination and extinction rates. However, similar issues might arise for studies of morphological disparity. Moreover, there potentially are additional implications of disparity patterns among species versus those among genera concerning the range of observable anatomical characters and whether disparity within genera is comparable to disparity among genera. If clades have some relatively slowly changing characters that workers have used to denote different genera, then we would expect to see congeneric species to cluster in morphospace; however, if such characters are rare, then within-genus disparity might approach among-genus disparity. Here, we use genus-level and species-level disparity patterns among acanthoceratid ammonoids from the Late Cretaceous. In particular, we examine whether these different level imply different evolutionary dynamics over a major ecological event (Ocean Anoxic Event 2) and how disparity within genera (i.e., among congeneric species) compares to disparity among genera. We find genus-level disparity somewhat inflates early acanthoceratid disparity but implies similar patterns over the OAE2. We also find that within-genus disparity is slightly lower than among-genus, but not hugely so. The combined results suggest that acanthoceratoid shell anatomy does not really show "genus" level characters, even if congeneric species do tend to be more similar to each other than to species in other genera. Thus, this might provide more of a warning for other types of studies using anatomical data (e.g., phylogenetic studies) than for disparity studies. Non-technical SummaryMany paleobiologists use genera to examine scientific questions. This leads to questions over whether this broader approach misses important species-level patterns. This study uses acanthoceratid ammonoids from the Late Cretaceous to examine disparity patterns at both the genus-level and the species-level. We specifically examine the disparity at both levels of this group over a time of high stress for this group, Ocean Anoxic Event 2 (OAE2). Our results show that genus-level disparity slightly exaggerates early acanthoceratid disparity but lowers to a similar pattern to the species-level disparity during OAE2. Within-genus disparity is shown to be slightly lower than among-genus, but not enough to be startling. Together, these results indicate that while some species within the same genus tend to be more alike to each other than those in other genera, there isnt a set of true "genus" level characters. This outcome leads to a warning against using anatomical data in phylogenetic studies, but less so for disparity studies.

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Socotra Cormorants in the Arabian Gulf represent a large, but isolated population with low genetic diversity

Almansoori, N. M.; Razali, H.; Muzaffar, S. B.; Chabanne, D. B. H.; Natoli, A.; Almusallami, M.; Naser, H.; Khamis, A.; Al Harthi, F.; Aldhaheri, L. S. R.; Alaleeli, M. M. B.; Al Diwani, F. M.; Manlik, O.

2026-04-03 ecology 10.64898/2026.04.01.712451 medRxiv
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The Socotra Cormorant (Phalacrocorax nigrogularis) is a threatened seabird endemic to the coastal areas of the Arabian Gulf and the Arabian Sea, two regions separated by the Strait of Hormuz. Conserving threatened species requires clear delineation of population boundaries and the evaluation of genetic diversity. However, information on population structure and genetic variation, necessary for such an assessment, is lacking for the Socotra Cormorants. In this study, we assessed population structure and genetic diversity of Socotra Cormorants using two contrasting genetic markers: (1) maternally inherited mtDNA cytochrome oxidase 1 (COI) and (2) a nuclear non-coding region, {beta}-fibrinogen intron 7 (FIB7). A total of 279 individuals were sampled from four colonies in the Arabian Gulf and one colony on Hasikiyah Island in the Arabian Sea. Findings based on COI-variation suggest that the Arabian Gulf colonies represent one large population with extensive gene flow between Gulf colonies--except for the most distant pair of colonies--but isolated from Hasikiyah in the Arabian Sea. COI-variation indicated significant differentiation between the colonies inside the Gulf and the Hasikiyah colony. This is consistent with the reported distribution patterns, and may reflect phylogeographic processes of the region. The Gulf population showed substantially lower COI-diversity, with significantly lower nucleotide and haplotype diversity compared to Hasikiyah. In contrast, FIB7 results indicated extensive connectivity among colonies, with no detectable population structure or significant differences between the Gulf population and Hasikiyah. This study presents the first characterization of population structure and genetic diversity of Socotra Cormorants. The low genetic diversity coupled with relative isolation of the Gulf Socotra Cormorants raises conservation concerns regarding their long-term viability by potentially reducing fitness and eroding their evolutionary capacity to adapt to environmental change. LAY SUMMARYO_LIThe Socotra Cormorant is a threatened seabird found in the Arabian Gulf and Arabian Sea, but little was previously known about its population structure and genetic diversity. C_LIO_LIWe analyzed 279 birds from five nesting colonies (4 in the Gulf and 1 in the Arabian Sea), using two genetic markers to assess population connectivity and variation. C_LIO_LIWe found that the Socotra cormorants inside the Gulf appear to form a large, genetically isolated population with relatively low genetic diversity. C_LIO_LIThis is the first study that evaluates population structure and genetic diversity of this endangered seabird. C_LIO_LIThis is important information for the conservation of the Gulf Socotra cormorants because low genetic diversity, coupled with relative isolation, is associated with reduced fitness, and suggests that they may have a lower chance to adapt to environmental changes. C_LI

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The Monophyly of Nycteria and Polychromophilus Parasites A Missing Piece in the Evolution of Malaria and Other Haemosporida

Pacheco, M. A.; Schaer, J.; Werb, O.; Mello, B.; Escalante, A. A.

2026-04-10 evolutionary biology 10.64898/2026.04.07.717123 medRxiv
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Haemosporida is a diverse order of vector-borne apicomplexan parasites infecting terrestrial vertebrates worldwide, including humans, but the evolutionary relationships among its genera remain unresolved. The phylogenetic placement of two bat-restricted genera, Nycteria and Polychromophilus, both of which lack erythrocytic schizogony, has varied across studies depending on taxon sampling and marker choice. To address this problem, an expanded dataset of near-complete mitochondrial (mtDNA) genomes together with nine nuclear loci were analyzed. Phylogenetic analyses of mtDNA recovered Nycteria and Polychromophilus as a strongly supported monophyletic clade. In contrast, analyses based only on the three mitochondrial coding genes (CDS) or a reduced nuclear dataset failed to recover their monophyly and showed low support and extensive topological conflict at deeper nodes. These results indicate that near-complete mitochondrial genomes recover phylogenetic signal that is not captured by reduced mitochondrial coding sequences or partial nuclear datasets. Molecular dating analyses further showed that divergence estimates for a putative Nycteria-Polychromophilus clade are compatible with the proposed times for bats diversification, and consistent with the broader haemosporidian timescale. When the Nycteria-Polychromophilus clade was incorporated as a calibration prior, divergence-time estimates became more precise without altering the overall evolutionary timeframe. Substantial mitochondrial gene-order rearrangements in a distinct Nycteria lineage were confirmed, highlighting structural divergence within this bat-associated group. In addition, heterogeneity in rates across mtDNA haemosporidian lineages was observed. Together, these findings support the existence of a distinct bat-associated clade whose deeper placement and evolutionary significance should be tested with broader phylogenomic sampling. Author SummaryMalaria parasites belong to a diverse group of organisms that infect many kinds of vertebrates, including birds, reptiles, and mammals (such as humans). Understanding how these parasites are related to each other is important for explaining how key biological traits have evolved. However, the relationships among major groups of haemosporidian parasites, including malaria parasites, remain unclear, particularly for those infecting bats. In this study, we focused on two groups of bat parasites, Nycteria and Polychromophilus, which share unusual biological features. The inferred evolutionary relationships of these two genera to other haemosporidians have been inconsistent across previous studies. By analyzing near-complete mitochondrial genomes, we found strong evidence that these two groups descended from a common evolutionary ancestor. In contrast, smaller datasets including nuclear genes failed to recover this relationship and produced conflicting results, suggesting that they lack sufficient information to resolve deep evolutionary relationships. We also found that this bat-associated lineage likely originated around the same time as early bats. In addition, we identified structural changes in the mitochondrial genome of one lineage, highlighting its evolutionary distinctiveness. Together, our results suggest that bats host a unique group of malaria parasites and demonstrate that more complete genetic data are essential for resolving their evolutionary history.

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Forensic Identification of Confiscated Helmeted Hornbill (Rhinoplax vigil) Casques and Implications for Individual Quantification in Wildlife Crimes

Shen, Y.; He, K.; Wang, W.; Huang, L.; Chen, J.

2026-04-06 zoology 10.64898/2026.04.02.715475 medRxiv
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In wildlife forensic practice, species identification and estimation of the Minimum Number of Individuals (MNI) for highly processed specimens have long relied on weight-based conversion methods, which may result in underestimation of the number of individuals involved in a case. Focusing on confiscated casque products of the helmeted hornbill (Rhinoplax vigil), this study combines macroscopic morphological examination with mitochondrial DNA barcoding (16S rRNA, COI, and Cytb) to explore a more robust approach for individual quantification. The results demonstrate that the conventional "weight-based" approach overlooks critical biological information contained in anatomical structures and cannot accurately reflect the actual number of individuals involved. Based on this, we propose an anatomy-based criterion centered on the principle of structural uniqueness: specimens retaining biologically unique beak or casque structures should be directly assigned to a single individual, whereas weight-based estimation should only be applied when original anatomical features are entirely absent. In addition, considering material loss during processing, we propose approximately 85 g as a reference threshold for estimating the number of individuals in heavily processed solid casque products. This approach improves the scientific rigor and accuracy of forensic identification and provides reliable technical support for the conviction, sentencing, and law enforcement of wildlife trafficking cases involving helmeted hornbill and other endangered species.

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Estimates of habitat selection reveal distinct habitat associations across life-stages in three coral-reef damselfish.

Sciamma, G.; Fakan, E. P.; Hoey, A.

2026-03-27 ecology 10.64898/2026.03.26.714170 medRxiv
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Understanding habitat association of animals and how they change through ontogeny is critical to predict the likely effects of habitat change on populations. We investigated how fine scale habitat associations of three common coral reef damselfish species changed among life-stages on reefs surrounding Lizard Island, northern Great Barrier Reef. All three species showed distinct habitat selection at settlement, however the degree to which these initial associations changed through ontogeny were species specific. Pomacentrus amboinensis associated with sandy areas throughout all life-stages; Pomacentrus chrysurus settled to areas with high cover of sand and rubble, but displayed no clear habitat preferences as juveniles or adults. Pomacentrus moluccensis settled to areas with high cover of fine branching corals before shifting to areas with relatively high cover of soft corals as adults. We also compared two different approaches to estimate habitat selection; one that quantified the benthic composition within the approximate home range of individuals versus a more widely used approach of recording a single point underneath the focal individual when they were first observed. Although results were broadly similar, the benthic composition approach revealed details that was overlooked using the single point method. Decreases in the availability of any of these preferred benthic habitats may adversely affect future populations, therefore understanding habitat associations and their transitions among life stages will be crucial in predicting future reef fish communities under ongoing coral loss and habitat change. This will require to systematically study a broader range of species, integrating relevant spatial and temporal scales.

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Disentangling shape and size in a population of unusually large Threespine Stickleback (Gasterosteus aculeatus) from Vancouver Island, British Columbia

Perry, S.; Duclos, K. K.; Jamniczky, H.

2026-04-03 evolutionary biology 10.64898/2026.04.01.715936 medRxiv
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Sarita Lake, British Columbia houses a distinctive population of threespine stickleback (Gastrosteus aculeatus L.) with a phenotype characterized by unusually large individuals relative to nearby conspecifics. We tested the hypothesis that members of this population are not isometrically larger but rather exhibit variation in allometric trajectories that reflect changes in developmental timing impacting the developmental-genetic architecture of the phenotype. We used 3D geometric morphometrics to characterize the size and shape of skulls, pectoral girdles and pelvic girdles from a sample of individuals from nearby freshwater and marine populations and compare them to a sample from Sarita Lake. We showed that individuals from the Sarita Lake population are larger in each body region compared to most other populations examined. Further, these individuals have dorsally expanded skulls and relatively robust pelvic armour. We also showed that the relationship between size and shape is differently structured among body regions and is heavily influenced by non-uniform sexually-mediated variation across populations sampled. Our results reflect complex underlying developmental trajectories, and we suggest that the large phenotype observed may be driven by fecundity selection on female size in combination with a limnetic trophic niche and relatively increased predation pressure in Sarita Lake.

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Genomes of two arid-zone marsupials uncover contrasting responses to climatic change

Feigin, C. Y.; Trybulec, E.; Ferguson, R.; Scicluna, E. L.; Sauermann, R.; Hartley, G. A.; O'Neill, R. J.; Pask, A. J.

2026-04-02 genomics 10.64898/2026.03.30.708387 medRxiv
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Small marsupials in the family Dasyuridae are a key component of Australias arid and semi-arid fauna, whose high species richness is proposed to reflect an opportunity-driven adaptive radiation. Despite growing interest in this group from both ecological and evolutionary perspectives, genomic data for most species is non-existent, or limited to a few marker loci. Here, we generated a chromosome-level reference genome and a de novo mitochondrial genome for the desert-dwelling Wongai ningaui (Ningaui ridei). The nuclear genome assembly is highly contiguous, with a scaffold N50 of 594.484 MB and high BUSCO gene recovery (93.84%). Additionally, we produced a draft assembly for the related, semi-arid slender-tailed dunnart (Sminthopsis murina). We then used these assemblies to explore the demographic histories of these species. We find evidence for contrasting patterns of population growth during the late Pleistocene and early Holocene, corresponding with differences in local climate, potentially consistent with differences in optimal habitat. The new genomic resources and demographic findings presented here provide a foundation for future studies on adaptive specialisation in this group of Australian marsupials. Significance StatementDasyurid marsupials are the primary carnivorous and insectivorous mammals in Australia. This diverse family includes species such as the endangered Tasmanian devil (Sarcophilus harrisii) and quolls (Genus Dasyurus), as well as an emerging laboratory model species, the fat-tailed dunnart (Sminthopsis crassicaudata). Despite the species richness within dasyurids, most species remain under-studied. This is particularly true of arid and semi-arid zone species, who are often small in size, live in remote habitats and are cryptic by nature. By creating genome assemblies for two dasyurid species, this study provides resources to support a variety of phylogenetic, population genetic and evolutionary developmental lines of research. Importantly, the studys finding that arid and semi-arid dasyurids show distinct trajectories of demographic change in response to historical climatic shifts may point to local adaptations with implications for the resilience of these species to ongoing and future climate change.

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Semen collection, short term storage, and cryopreservation in the Texas horned lizard (Phrynosoma cornutum)

Julien, A. R.; Griffioen, J. A.; Perry, S. M.; Doege, R.; Burger, I. J.; Barber, D. R.

2026-04-06 zoology 10.64898/2026.04.03.716302 medRxiv
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As global reptile populations continue to decline, improving reproductive success in managed populations of listed species, such as Phrynosoma cornutum (the Texas horned lizard) has become increasingly critical for species survival. One understudied area of reproductive research in reptile species is gamete collection and storage, a crucial component for maintaining genetic diversity. In Texas, semen was collected from wild P. cornutum (n = 20) in June 2025. Semen collection was performed via electroejaculation (EEJ) under alfaxalone anesthesia. Prior to semen collection, snout-vent-lengths (SVL) and weights were recorded and testes measurements were taken using a portable ultrasound. Average sperm motility and concentration across all lizards was 83.7% and 85.7 x 106 sperm/mL, respectively. While lizards with longer SVLs had higher sperm motility, weight and testis size did not affect sperm parameters. Samples were extended in INRA96 and divided for use in cold-storage longevity or cryopreservation trials. Samples under cold-storage conditions were assessed for motility daily for 10 days. Motility was not significantly reduced until 48 hours post-collection and maintained 19% motility at day 10. For cryopreservation, samples were diluted 1:1 in INRAFreeze cryopreservation media and frozen in liquid nitrogen, then immediately thawed. Average post-thaw sperm motility was 13.9%, with the highest post-thaw motility recorded at 38.2%. This is the first report of semen storage and cryopreservation in Phrynosoma and provides valuable insight into semen storage potential in reptile species.

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Gene Flow Creates Fuzzy Species Boundaries in Fence Lizards

Leache, A.; Davis, H.; Guerra, E.; Herrera, A.; Lemos-Espinal, J.; Fujita, M.; Myers, T. C.; Singhal, S.

2026-04-10 evolutionary biology 10.64898/2026.04.07.717035 medRxiv
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Species delimitation is a fundamental challenge in systematic biology, particularly for geographically variable taxa with hierarchical population structure and gene flow. Migration-aware coalescent models provide a powerful framework for investigating lineage divergence and accurately defining species boundaries. In this study, we combine statistical evaluations of gene flow with phylogenetic and population structure analyses to delimit species of fence lizards within the Sceloporus undulatus complex, a group characterized by extensive population subdivision, mitochondrial DNA introgression, and nuclear gene flow. We find that the undulatus complex exhibits uneven variation in genetic, morphological, and bioclimatic traits, resulting in variable distinctiveness among groups. In some cases, species boundaries are recognized by clear genetic discontinuities without gene flow. In others, shallow divergence, paraphyly, and gene flow produce leaky boundaries and fuzzy species limits. Mitochondrial introgression is extensive and concentrated at species boundaries, whereas nuclear gene flow occurs between only a few species and at much lower levels than within species. Neither within-species populations or species are substantially diverged across morphology or bioclimatic space, highlighting the limited utility of these traits for diagnosing species in this group. By integrating estimates of gene flow with phylogenetic and population structure analyses, this study provides a robust and biologically meaningful revised taxonomic framework for the undulatus complex that identifies independently evolving lineages as species.

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Bed and breakfast in the bush: Selection of resting sites and kill sites by leopards (Panthera pardus) on Namibian farmland

Sabeder, N.; Oliveira, T.; Portas, R.; Hocevar, L.; Flezar, U.; Wachter, B.; Melzheimer, J.; Krofel, M.

2026-03-20 ecology 10.64898/2026.03.18.712594 medRxiv
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Sleeping and feeding are crucial for survival of any animal. In case of large predators, knowing where these activities occur can help us understand their behavioural adaptations for coexisting with people and could help mitigating human-carnivore conflicts. Leopard (Panthera pardus) is an elusive and highly adaptable large felid that mostly lives outside protected areas and can survive also in close proximity to humans. However, most leopard research in Africa has been conducted in protected areas and we poorly understand leopards habitat selection while resting and hunting. To shed light on their coexistence with humans, we investigated habitat features influencing leopard selection of resting and kill sites on farmlands in central Namibia, using generalized linear mixed models (GLMM) under a use-availability study design and blinded field-sampling. Leopards primarily selected resting sites that were located in mountainous, steep, rugged terrain and sites with good concealment while kill sites were selected in mountainous habitats. Human infrastructure did not affect leopard resting and kill site selection. Thus, the capacity of leopards to perform essential life-supporting behaviours while coexisting with people appears to be primarily driven by their ability to remain concealed, rather than spatially avoiding humans.

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The effect of chronic, latent Toxoplasma gondii infection on human behavior: Testing the parasite manipulation hypothesis in humans

Valenta, K.; Grebe, N.; Kelly, T.; Applebaum, J. W.; Stern, A.; Traff, J.; Satishchandran, S.; Rosenbaum, S.; Lantigua, V.; Lee, A. C. Y.

2026-03-20 evolutionary biology 10.64898/2026.03.16.712071 medRxiv
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Parasitism is one of the key, structural, interspecific interactions in ecology. One remarkable parasitic strategy that has been documented in multiple systems is the behavioral manipulation of hosts to increase parasite fitness. While not yet documented in humans, we propose that a ubiquitous zoonotic parasite - Toxoplasma gondii - may change human behavior to favor the parasite by increasing the fitness of the parasites definitive host - cats. Specifically, we assess the possibility that human behavioral changes resulting from chronic, latent T. gondii infection lead to measurable changes in attitudes, actions and dopaminergic responses towards cats that function to increase domestic cat fitness. We assessed the potential role of humans in the T. gondii lifecycle by identifying and testing behavioral changes in humans that benefit the parasite; specifically, human affection for cats. We assessed T. gondii infection status in 68 participants using T. gondii serum antibody testing, and assessed their attitudes towards cats in three ways: i) surveys, ii) participant behavior in the presence of domestic cats, and iii) participant oxytocin levels before and after interactions with cats to assess dopaminergic changes. Only 2 of 68 participants were positive for T. gondii antibodies, limiting statistical power. However, our results indicated that T. gondii-positive participants both reported a greater affection for cats in surveys, and spent more time engaged with cats during behavioral trials than T. gondii-negative participants (87% of study time engaging with cats vs 75%). Oxytocin results were inconclusive.

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Extreme disparity in the appendicular skeleton of domestic dogs (Canis familiaris)

Roberts, L. E.; Binfield, O. F.; Charles, J. P.; Comerford, E. J.; Bates, K. T.; Goswami, A.

2026-03-25 zoology 10.64898/2026.03.22.713490 medRxiv
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Domestic dogs (Canis familiaris) display more morphological variation than any other mammal. Cranial morphology has been extensively studied, as have the relationships with function, development, genetics, veterinary medicine, and breed welfare. Postcrania remain comparatively understudied, despite well-documented breed-specific predispositions to musculoskeletal disease. Here, we apply three-dimensional landmark-free morphometrics to quantify the shape of 743 elements from 213 dogs, including the scapula, humerus, radius, ulna, pelvic girdle, femur, tibia, and fibula. We assess integration among limb elements and investigate drivers of shape variation within and between breeds. Across most breeds, limb bone shape is strikingly similar. Dachshunds, however, exhibit distinct morphology across all elements and one to two orders of magnitude greater variation than any other breed. Despite this disparity, integration remains high between all element pairs. Remarkably, we find no significant relationship between bone shape and body mass, age, or pathology, but comparison with historic specimens reveals marked changes in dachshund long bone shape over the past [~]150 years. These extreme differences are not shared by other sampled chondrodysplastic breeds, underscoring the need to understand morphological diversity beyond simple categorisation. These findings provide a quantitative framework for linking postcranial morphology with function, disease risk, and evidence-based improvements to canine welfare.

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Comparative studies of transmission mode and localisation patterns of common RNA viruses in Queensland fruit fly (Bactrocera tryoni) reveal most are vertically transmitted

Bidari, F.; Morrow, J. L.; Pradhan, S. K.; Riegler, M.

2026-03-23 microbiology 10.64898/2026.03.20.713308 medRxiv
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RNA viruses are common in tephritid fruit flies including the Queensland fruit fly, Australias most significant horticultural pest. For many their transmission, tissue tropism and load across host development remain unexplored. Yet these factors are important for host biology, ecology and pest management. We investigated Bactrocera tryoni orbivirus (OV), Bactrocera tryoni xinmovirus (XV), Bactrocera tryoni toti-like virus (TLV) and Bactrocera tryoni iflavirus species 2 (IVsp.2) that commonly coinfect B. tryoni laboratory populations. OV and XV transmission was vertical within and on eggs, while TLV transmission was vertical within eggs. IVsp.2 was not detected in eggs but was present in adults; however, IVsp.2 was horizontally transmitted, with viral load increasing with cohabitation time with infected flies. Horizontal transmission was not observed for the other viruses. OV had a similar load across all tissues, while XV was consistently more abundant in ovaries. TLV had a high viral load in the brain whereas IVsp.2 was abundant in the thorax, foregut and midgut. Besides differences in eggs, the viruses were detected in all other developmental stages, but viral load patterns differed: viral load remained constant for TLV, fluctuated for OV and XV, and was low in pre-adult stages and high in adults for IVsp.2. Our findings demonstrate distinct transmission strategies and tissue tropism among the viruses, providing new insights into their epidemiology and role in host biology. Furthermore, contrary to prevailing views that viruses are generally horizontally transmitted, most known RNA viruses of B. tryoni are vertically transmitted affecting the evolution of host-virus interactions.

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Intertidal Gastropods (Gastropoda: Mollusca): Insights on diversity and distribution in the Mumbai Metropolitan Region, India

Ansari, R. M.; Patade, P.; Modi, S.

2026-03-30 zoology 10.1101/2025.11.20.689409 medRxiv
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Marine biodiversity documentation from the Mumbai Metropolitan Region (MMR) remains neglected despite the region having diversity of marine coastal habitats. The regions intertidal is one such habitat where species documentation remained heavily deficient due to lack of assessments and general apathy towards the habitat. This study addresses the issue of data deficiency of one of the largest taxa, Gastropoda through a decade long citizen science project, Marine Life of Mumbai. There exist large gaps in taxonomic research that have led to inconsistencies in species identification and inadequate ecosystem representation. This study addresses these issues by focusing on one of the largest taxa, the Molluscan class Gastropoda within the MMR. We present the spatial distribution of gastropod assemblages from 28 rocky, sandy and muddy intertidal sites within the Mumbai Metropolitan Region, on west coast of India. A total of 163 species were recorded from 2164 observations of marine gastropods. Among these, 29 species, 34 genera and one family Limapontiidae are new records for the region. Additionally, this study reports rediscoveries of 7 species from their type locality, with 5 species of Heterobranchs recorded after 78 years: one species from Neogastropoda, Lataxiena bombayana, after 131 years and one from Siphonariida, Siphonaria bassiensis after 31 years, from their type locality. These species are herein illustrated with detailed morphological descriptions and their local distribution on 28 sites in the Mumbai Metropolitan Region. Through this study we elucidate that the citizen science efforts and the subsequent taxonomic analysis provide an effective and low-cost method for filling data gaps from large, understudied geographical areas.