DOI: 10.3391/ai.2025.20.2.152871

Authors: Anna J. Phillips, Jason Reilly, Don Ashton, Dennis J. Richardson, Makiri Sei, William E. Moser

Abstract: The Common North American Turtle Leech, Placobdella parasitica, was reported in 2023 using the Northwestern Pond Turtle, Actinemys (Emys) marmorata, as a host in the Lower Rogue River, southwestern Oregon, USA. Molecular analysis and haplotype networks based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence revealed that this introduced population has very low haplotype diversity and is likely the result of a single introduction of a gravid adult, an adult brooding eggs or hatchlings, or a small number of related individuals. While we determined that the precise source population was not represented in our sampling, there was strong similarity between the representatives from Oregon and those from near the Arkansas-Missouri border. Molecular evidence also supports this as a recent introduction, likely via human activity, and potential pathways of introduction are considered. Our results agreed with a previous study of morphological and molecular data of P. parasitica samples from throughout its native range in North America that found the species to be widely distributed, morphologically conservative, and molecularly variable. Using COI sequence data with Bayesian Inference, we evaluated species cohesiveness using species delimitation analyses (ABGD, mPTP, bPTP, and GMYC) that revealed 13 species entities that were clustered by geographic region. Identifying the source population and possible invasion pathways of this introduced population and assessing the dispersal capabilities of P. parasitica could slow and prevent further range expansion in the western USA. Introduced P. parasitica has not been recognized as a threat to the health of the Northwestern Pond Turtle or the Rogue River ecosystem so its presence has not been systematically monitored, but any introduced parasite is concerning given that the U.S. Fish and Wildlife Service has proposed this turtle species for Threatened status under the Endangered Species Act.

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DOI: 10.3391/ai.2025.20.1.136400

Authors: Elena K. Kupriyanova, Guillemine Daffe, Samaneh Pazoki, Manal Al-Kandari

Abstract: Spirobranchus tetraceros (Schmarda, 1861), originally described from New South Wales, Australia, was later reported as a widely distributed succesful species of Indo-Pacific origin, including as Lessepsian migrant to the Mediterranean, until evidence has accumulated that the nominal taxon is a large complex of morphologically similar species. Specimens of Spirobranchus cf. tetraceros recently discovered in the Western Mediterranean (Valencia, Spain) morphologically resembled those of S. multicornis from the Red Sea rather than S. tetraceros sensu stricto from Australia. However, genetic studies proved that sequences of the introduced specimens match neither those of the S. tetraceros morphotype from warm temperate Australia (NSW) nor those of S. multicornis from the Red Sea. Subsequently, Kupriyanova et al. (2022) designated a neotype of S. tetraceros from New South Wales supported by DNA sequence data and demonstrated that several species of the S. tetraceros complex exist in Australia alone. This study examined several populations of the S. tetraceros complex world-wide in search of the source population for the Western Mediterranean invader and demonstrated its identity with S. arabicus widely distributed in the Persian (Arabian) Gulf.

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DOI: 10.3391/ai.2025.20.1.134650

Authors: Emily M. Zavacki, Nathalie B. Reyns, Jeffrey A. Crooks, Michel A. Boudrias

Abstract: The non-indigenous bryozoan, Amathia verticillata, has a worldwide distribution and commonly colonizes anthropogenic structures such as docks. Although widely recognized to house marine invertebrates within its structure, little is known regarding how the biogenic material produced by A. verticillata influences the marine community dynamics. The purpose of this study was to document the temporal patterns of A. verticillata and their associated marine invertebrate community in an urbanized estuary, Mission Bay, San Diego, CA, USA. We quantified A. verticillata percent cover and the abiotic conditions between July 2021–2022. The percent cover of A. verticillata varied temporally with temperature, with highest percent cover on docksides when temperatures were warmest. We also collected A. verticillata colonies of varying morphology and size to determine if abundance, density, and diversity of the marine invertebrate community associated with A. verticillata was influenced by its biogenic material and structural complexity. All invertebrates were identified to the lowest taxonomic level possible. We identified 20 families, 19 genera, and 12 organisms to species, representing 2 non-indigenous species (NIS), 2 likely NIS, 3 cryptogenic, and 5 native species. The most abundant taxonomic groups were marine amphipods, isopods, tanaids, and polychaetes. Furthermore, we identified juvenile stages and females with eggs living within A. verticillata. The invertebrate community varied significantly by A. verticillata morphotype and structural complexity. In general, there was greater invertebrate diversity in the elongated versus compact morphotype, and the invertebrate counts and diversity increased with structural complexity. Collectively, our results suggest that A. verticillata functions as a habitat-producing ecosystem engineer that may be providing an important nursery habitat for diverse groups of marine invertebrates, including other NIS, on anthropogenic structures.

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