Neogogatea Chandler and Rausch, 1947, is a small genus of cyathocotylid digeneans parasitic in the intestines of birds of prey. The genus contains only 3 species: 2 from the Nearctic and 1 from the Palearctic. No sequence data from mature, properly identified representatives of Neogogatea were available until now. In the present study, we collected mature adult Neogogatea kentuckiensis (Cable, 1935) Hoffman and Dunbar, 1963, from osprey in Georgia, Florida, and Delaware, and sequenced fragments of the nuclear large ribosomal subunit (28S) gene and cytochrome c oxidase subunit I (COI) mtDNA gene. We used 28S sequence data for phylogenetic inference and COI data for comparisons at the species level. In the phylogenetic tree, N. kentuckiensis was situated in a clade with representatives of the genera Mesostephanus Lutz, 1935, Braunina Wolf, 1903, and an unidentified cyathocotylid cercaria from Australia. The observed variability in the COI gene between our isolates suggests the need for collecting fresh, well-fixed, and mature specimens from a broader geographic range to test for the presence of more than 1 Neogogatea species in New World osprey.

In a parasitological survey of Asiatic toads (Bufo gargarizans) from Chongqing, China, a novel myxosporean was encountered. The species, Cystodiscus chongqingensis n. sp., was found in the gallbladder of toads. The elliptoid myxospores were morphologically consistent with a Cystodiscus species but were distinct from other congeners by myxospore dimensions and DNA sequence comparisons. Myxospores were 14.2 ± 0.4 μm long (13.6-14.9 μm) and 11.1 ± 0.5 μm wide (10.4-12.0 μm), and the polar capsules were 4.6 ± 0.3) μm long (4.0-5.1 μm) and 3.4 ± 0.3 μm wide (2.6-3.8 μm). Phylogenetically, this new species was sister to all previously described and sequenced Cystodiscus species. Also, the predicted secondary structures of helices 18 and 24 in its small subunit ribosomal RNA were distinct from those of other Cystodiscus species, highlighting its unique phylogenetic position within Cystodiscus. Divergence time estimates suggest that C. chongqingensis n. sp. emerged in the Paleogene Period, significantly earlier than other Cystodiscus species. The discovery of this novel species that represents a unique Cystodiscus lineage warrants further investigations to evaluate whether other Asian Cystodiscus species fall within the same lineage.

Alaria is a small genus of diplostomids that infect the intestines of mammalian definitive hosts. The life cycles of Alaria spp. require amphibian second intermediate hosts. However, snakes and small mammals often serve as paratenic hosts, and humans may be accidental dead-end paratenic hosts. Recently, the genus was expanded to include members of the former genus Pharyngostomoides, which primarily parasitizes common raccoon Procyon lotor. In the present study, we collected representatives of several Alaria spp. from amphibians, reptiles, and mammals in Georgia, Louisiana, North Dakota, and Wisconsin. Newly collected and previously available materials were used for morphological and molecular study. Additional specimens, including type series, were morphologically examined from various museums, teaching, and personal collections in North and South America. These archival specimens were critical in helping evaluate species diversity and assess potential evolutionary patterns of the genus. We provide descriptions of 3 new Alaria spp., 2 of them are based on new and museum specimens from common raccoons in Georgia and Minnesota, and the third new species is described based on museum specimens only from a mountain lion Puma concolor in Paraguay. The morphology of a species-level genetic lineage likely representing a new species is described based on specimens from a fisher Pekania pennanti in Wisconsin. Descriptions of Alaria procyonis (new material), Alaria marcianae (previously sequenced museum specimens), and Alaria nasuae (museum material; first description from wild-collected host) are provided. A redescription of Alaria adenocephala is provided based on type materials. Fragments of 3 genetic loci (28S + ITS region rDNA and COI mtDNA) were sequenced for the new materials (4 species; 1 species-level lineage). The name Alaria nattereri Lutz, 1933 is considered a nomen nudum. New sequences (ITS region and COI) of several previously studied Alaria isolates (5 species; 2 species-level lineages) were generated, along with the mitochondrial genome of Alaria ovalis, one of the species from raccoons. These DNA sequences were used to infer the phylogenetic relationships among Alaria spp. In total, our study increases the number of nominal Alaria spp. known from 10 to 14, of which 12 are limited to the Americas. A new key to Alaria spp. based on adult morphology is provided.

Separate bodies of literature suggest that the ecology and evolution of host-parasite systems are influenced by the quality of a host's diet and priority effects (i.e., when the order of exposure to multiple parasites influences the outcome of the infection). Although resource competition is invoked as a mechanism responsible for priority effects, the effect of host diet quality on priority effects is unexplored. We tested the hypothesis that low-quality diets reduce priority effects between the bacterial parasite Pasteuria ramosa and the microsporidian Hamiltosporidium tvaerminnensis in their daphnid host. We found that P. ramosa benefits from prior residency when hosts are fed high phosphorus (i.e., high-quality) but not low phosphorus diets. We were unable to detect priority effects for H. tvaerminnensis. These results are consistent with evidence from single-infection experiments on the same parasites, suggesting that low phosphorus diets could reduce resource competition between these parasites. Our study shows how the host's environment can influence infection outcomes by moderating parasite interactions.

The field of parasitology, and thus biodiversity research more broadly, is faced with the unfortunate reality that our understanding of parasite biodiversity can be only as good as our ability to sample parasite host species. Although the sampling of many host species is trivial, there typically remains a subset of species across any host group of interest that is difficult to sample due to rarity, habitat, body size, or some other trait. The result is a blind spot in our understanding of parasite biodiversity that is centered around parasite species that infect hosts that are rarely sampled by humans. However, for many groups of hosts, the daunting task of obtaining host samples has already been done, and these samples exist in the form of natural history collections at institutions across the world. With avian malaria parasites and other haemosporidians as an example, I demonstrate that significant host sampling gaps exist in the United States and Canada. Bird species that have not been sampled for molecular haemosporidian research typically are associated with aquatic habitats, significantly greater masses, and more restricted geographic distributions than are bird species that have already been sampled. These unsampled host species are likely to be infected with a high richness of previously undiscovered avian haemosporidian genetic lineages. However, natural history collections in the United States can be used to nearly completely address these sampling gaps with tissue samples currently housed in these institutions. The result of this analysis indicates that the future of parasite biodiversity research is dependent on the use and support of natural history collections and other biorepositories.

Seasonal patterns in parasite diversity and prevalence are determined by a suite of factors ranging from environmental conditions (e.g., temperature, precipitation) to host behavior and traits. The forces shaping these patterns are increasingly unstable due to anthropogenic climate change, emphasizing the importance of leveraging natural history collections to understand how historical environmental conditions contributed to the spatiotemporal distributions of parasites and parasitic diseases. We implemented frameworks from metacommunity analyses to test for seasonal trends in parasite community structure attributable to host and abiotic environment in 2 North American shrew species, Sorex cinereus and Sorex monticola. Shrews were collected using snap traps and pitfall traps periodically from 2009 to 2018 at 2 sites in Cowles, New Mexico. Whole gastrointestinal tracts from shrews were screened and tapeworm taxa were identified to genus using high-throughput amplicon sequencing of the 28S rRNA gene. Elements of metacommunity structure (EMS) revealed coherent, dynamic cestode metacommunities indicative of idiosyncratic responses of parasite taxa to seasonal trends in climate variables. We used boosted regression trees to identify latent variables predictive of cestode metacommunity structure and identified "day of the year" as having the greatest relative influence on parasite community structure, followed by precipitation and host body size. This work demonstrates for the first time the utility of the EMS framework for detecting fine-scale seasonal dynamics in parasitic helminth communities.

To date, no complete genomes from any species of fish-infecting coccidia have been sequenced, including any from one of the most speciose genera of fish-infecting coccidia, Goussia. To address this data gap, we generated and annotated complete mitochondrial (mt) genomes of 2 local fish-infecting Goussia species: Goussia degiustii and Goussia leucisci. Parasite DNA was extracted from infected spleen and kidney samples from common shiner (Luxilus cornutus) specimens. PCR and Sanger sequencing were conducted to generate whole nuclear (nu) 18S rDNA sequences and complete mt genomes from each species. Despite being members of the same genus, the mt genomes of G. degiustii and G. leucisci are highly divergent with respect to both content and organization. The mt genome of G. degiustii has the same organization as the mt genomes of parasites in the family Eimeriidae (sensu stricto). A phylogenetic analysis of nu 18S rDNA sequences combined with mt cytochrome c oxidase subunit I sequences (where available) from 56 species of related coccidia placed G. degiustii in a clade with 5 fish-infecting enteric species exhibiting nodular development and G. leucisci in a different clade with 5 fish-infecting species exhibiting epicellular development. Additional molecular data, but especially mt coding sequences and whole-genome data, need to be obtained from other fish-infecting Goussia species to resolve the apparent paraphyly of this genus and uncover the genome organizations of these parasites.

Building on other scholars' relatively recent insights of the relationships of polyopisthocotyleans and trematodes, here for the first time it is hypothesized that this relationship favors the view that blood flukes are the primordial digeneans, and blood feeding per se was a factor facilitating the transition to endoparasitism. In contrast to other hypotheses of digenean origins that are "mollusc first" and then suggest acquisition of the vertebrate host secondarily, this is a "vertebrate first" hypothesis that features later capture of molluscan or annelid hosts. Capture of molluscan or annelid hosts may have been facilitated by their possession of hemoglobin. This hypothesis is also distinctive in suggesting that the 2-host blood fluke life cycle is not secondarily truncated but in fact represents the basal condition and, furthermore, provides a platform from which 3-host life cycles could emerge. The hypothesis is supported by long-standing observations that early diverging blood flukes tend to appear in early diverging vertebrate host lineages, blood fluke intermediate hosts and intramolluscan larval stages are exceptionally diverse, and blood flukes exhibit cercariae with tails ranging from simple buds to complex forked swimming structures. These ideas have nonetheless heretofore never been gathered into an explicit statement hypothesizing the early divergence of blood flukes, manifested today in definitive hosts ranging from early diverging fish lineages to birds and mammals, a host breadth unparalleled among other digenean groups. This hypothesis supports the sister group relationships of aspidogastreans and digeneans, but unlike others it does not posit a major role for aspidogastrean-like organisms giving rise to primordial digeneans. It also points out problems in concluding that some digenean groups such as brachylaimids or transversotrematids are basal digeneans. This review also considers how the complex intramolluscan asexual reproduction program of digeneans may have arisen, based on new insights from functional genomics.

The family Didymozoidae is a speciose group of fish parasites with unusual morphologic and life-history characters. In the Caribbean, juvenile didymozoids are common in demersal fishes such as snappers (Lutjanidae), but few deoxyribonucleic acid (DNA) sequences are available from these developmental stages in this region. In the present study, 1 complete and 1 partial juvenile didymozoid from a snapper (Lutjanus sp.) from Puerto Rico were characterized morphologically, and the complete ribosomal DNA operon and mitochondrial genome were sequenced. The specimens resembled the allomonilicecum morphotype, and phylogenetic analysis indicated membership in the Didymodiclininae, which comprises the genera Didymodiclinus and Paragonapodasmius. The presence of a ventral sucker excludes Paragonapodasmius, which has also not been recorded in the Atlantic region. Identification of the specimen as a member of Didymodiclinus, which is known from the broader region of our study, was generally supported in phylogenetic analysis. Mitogenome phylogenies recovered Didymodiclinus with Azygiidae, consistent with the classification of these taxa within Hemiurata. However, the position of the Hemiurata within the Digenea fluctuated radically in mitogenome trees obtained with different analytic approaches, particularly depending on whether alignments were based on amino acid translations or nucleotides. The present data have value for the study of the distribution, life history, and diversity of these parasites in the Caribbean, particularly given the negative effects of didymozoids on highly valued fishes such as tunas and groupers.

The helminth fauna of birds has been the focus of many parasitological studies, which illustrate the especially diverse nature of avian helminth communities. In this study, we investigated the species richness, identity, and abundance of helminth infections in 17 species of birds representing 6 orders from the San Francisco Bay Area of California. A total of 70 birds were provided by wildlife rehabilitation centers and hunting groups from 13 California counties. Helminths were identified morphologically to the lowest taxonomic level, and, whenever possible, trematode identifications were confirmed using large ribosomal subunit (28S) rDNA sequences. Eighty-seven percent of birds were infected with helminths, including 86% infected with nematodes, 36% with trematodes, and 16% with either cestodes or acanthocephalans. We identified 39 helminth taxa, including 15 nematodes, 15 trematodes, 5 cestodes, and 4 acanthocephalans, which resulted in 33 new geographic records and 22 new host records. Among the orders of birds dissected, the Anseriformes Wagler, 1831, supported the highest total richness of helminths (18 taxa), although the highest helminth richness values in individual host species were observed in Nycticorax nycticorax (black-crowned night heron) L., 1758, and Ardea herodias (great blue heron) L., 1758, both with 7 taxa. Nycticorax nycticorax was also infected with Ribeiroia ondatrae (Price, 1931), which represents a new definitive host record in the United States. Our results demonstrate the need to generate baseline helminth survey data, which can be used to help understand the knowledge gaps for parasite life cycles, as well as patterns of parasite distribution.

Trichomonas gallinae is a protozoan parasite of the upper digestive tract of poultry and wild birds and poses a serious threat to the wild bird population and the pigeon industry globally. Therefore, rapid diagnosis and timely treatments are necessary to control T. gallinae. Although some conventional diagnostic methods have been described previously, these methods are hampered by omissions or high costs. In this study, the combination of biotin-labeled and FAM-labeled primers and probes for recombinase-aided amplification (RAA) with a lateral flow dipstick (LFD) was investigated to visualize the RAA results. The RAA-LFD assay was established for the on-site, rapid, and sensitive detection of T. gallinae. The RAA-LFD assay with Toxoplasma gondii, Neospora caninum, and Tetratrichomonas gallinarum did not produce a cross-reaction, which indicated that this RAA-LFD assay is specific for detecting T. gallinae. In addition, the RAA-LFD assay demonstrated high sensitivity with the lowest detection limit of 2.78 × 101 copies/μl of the Fe-HYD standard plasmid for T. gallinae. The complete detection process of the RAA-LFD assay was found to require 45 min. These results suggest that the RAA-LFD assay established in the present study may be promising for the rapid, specific, and sensitive detection of T. gallinae during surveillance efforts.

Tropical theileriosis, caused by Theileria annulata and transmitted by Hyalomma ticks, is one of the fundamental diseases affecting cattle and resulting in substantial economic losses. In recent years, there has been an increase in the rate of buparvaquone (BPQ) treatment failure cases, particularly in infections caused by parasite populations with certain mutations on the parasite's cytochrome b (Cyto b) gene. Biological fitness of the mutated, drug-resistant parasite is an important parameter to limit the spread and delay the emergence of drug resistance in new areas. Programmed cell death (apoptosis) is a defense mechanism against intracellular infection agents such as T. annulata that have the unique ability to induce uncontrolled but fully reversible proliferation of the host cells following invasion. The cells treated with BPQ in vitro survive for a few more days and undergo apoptosis. Besides, the capacity of drug-resistant T. annulata populations to inhibit apoptosis is still questionable. Here, we have evaluated the fitness costs in both mutated drug-resistant and wild-type clonal cell lines under long-term in vitro conditions in the absence of BPQ pressure. This study also addressed the question of what occurs when the parasite population develops drug resistance by evaluating the effects of the P253S mutation, which confers BPQ resistance, on the apoptotic activity of T. annulata populations in vitro. The fluctuations observed in both the intensity of the bands and the half-maximal inhibitory concentration values indicated the presence of a dynamic change. However, this did not impose a fitness cost on either population during the routine in vitro maintenance for up to 50 passages. The drug-resistant parasite population harboring the P253S mutation successfully adapted to in vitro culture alongside the drug-sensitive population in the absence of drug pressure. The percentage of apoptotic cells observed in the BPQ-resistant clonal cell line between 0 and 72 hr after BPQ treatment remained almost the same as that of the drug-sensitive one. Thus, the mutated parasite populations exhibit resistance to apoptosis, and this resistance persists even after the withdrawal of BPQ. This study represents a foundational step in understanding the fitness costs associated with BPQ resistance in T. annulata under in vitro conditions, with a particular focus on the effects of the P253S mutation in the Cyto b gene on the fitness of BPQ-resistant parasite populations. Although these results do not directly quantify fitness costs, they indicate that drug-resistant mutations such as P253S may persist and spread in natural populations, even in the absence of drug pressure.

We determined the seasonal distribution and abundance of ticks on a nature preserve and adjacent walkways of a university campus and evaluated their Rickettsiales carriage. Ticks were collected weekly by flagging or dragging 17 sites from June 2022 through May 2024, and environmental parameters were recorded. Ticks were identified according to species, sex, and life stage using standard keys. DNA was extracted, and a 12S tick mitochondrial DNA fragment was amplified and sequenced to verify tick identification. EvaGreen polymerase chain reaction (PCR) was used to test ticks for spotted fever group Rickettsia (SFGR) and Anaplasmataceae followed by amplification and sequencing of ompA and groEL fragments to identify the respective organisms detected. Diversity of Rickettsia and Ehrlichia was examined by analyzing sites with variable numbers of tandem repeats. Seven hundred sixty-eight ticks were collected, including 257 Amblyomma americanum Linnaeus (19.5% female, 21.8% male, and 58.8% nymphs), 461 Amblyomma sp. larvae, 45 Ixodes scapularis Say, and 5 Ixodes keiransi Beati, Nava, Venzal, and Guglielmone. Amblyomma americanum was collected from March through October, and I. scapularis was found from November through March. SFGR DNA was detected in 36.5% of ticks (66 A. americanum and 7 I. scapularis) and 69.9% of larval pools. Only Rickettsia amblyommatis was identified in Amblyomma ticks; I. scapularis contained Rickettsia buchneri. Eight Amblyomma ticks that tested PCR positive for Anaplasmataceae contained Ehrlichia chaffeensis (4 ticks), Ehrlichia ewingii (2), and Panola Mountain Ehrlichia sp. (2). Several variable-length PCR target (VLPT) variants of E. chaffeensis and plasmid gene tandem repeat variants of R. amblyommatis were detected in sympatric ticks collected from the study site. In conclusion, tick-borne rickettsiae found within small-scale green urban areas may pose risks of tick-borne infections for individuals using these places.

The genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina) includes vector-borne, intracellular blood parasites that infect a wide range of vertebrate hosts, including frogs and snakes. Species identification of bloodstream forms is difficult because there are usually not many morphological characters to distinguish species and gamonts of genetically different isolates. Traditionally, Hepatozoon spp. have been distinguished by characters such as pathology to host erythrocytes and/or developmental stages in the invertebrate vector. However, recent molecular studies are finding that these distinctions do not correlate with gene sequence data. Specifically, this is the case for 2 closely related Hepatozoon species that infect North American anurans, Hepatozoon catesbianae and Hepatozoon clamatae. Gamonts infecting erythrocytes of these 2 species are morphologically indistinguishable, and traditionally they have been differentiated based on whether they fragment the host erythrocyte nucleus; however, recent genetic studies indicate that this character does not correlate with specific genotypes. In this study, we sampled frogs and snakes from the east central United States for Hepatozoon spp. and compared their effects on the host erythrocytes with genotype. Hepatozoon spp. infections were morphologically characterized with microscopy and molecularly characterized with Sanger sequencing at 3 loci (COIII, ITS-1, and 18S rDNA). We found that individuals of 3 ranid species (Rana catesbeiana, Rana clamitans, and Rana sphenocephala) were infected with Hepatozoon species. Of those, only individuals of R. clamitans were infected with Hepatozoon spp. that fragmented the host erythrocyte nuclei. As previously reported, mixed infections, determined with both microscope observation of fragmentation characters and Sanger sequencing, were common and obfuscated species identification and the usefulness of the fragmentation character in differentiating H. catesbianae and H. clamatae infecting North American anurans. We recommend that future studies aim to establish better definite links between cellular fragmentation characteristics and DNA sequences to differentiate these 2 species. We also report and characterize Hepatozoon cf. sipedon from 3 snake species. Infected erythrocytes in all 3 snake species displayed variation in the extent of cytoplasm clearing. Sequences from these 3 snakes were identical at ITS-1 and 18S rDNA (COIII was sequenced from only 1 isolate). In our 18S rDNA phylogeny, Hepatozoon spp. infecting frogs were in a single clade, whereas Hepatozoon spp. infecting snakes were found in multiple clades with Hepatozoon spp. that infect other hosts, including lizards, small mammals, and frogs. This study adds to a growing number of studies that indicate snakes are capturing Hepatozoon spp. from their prey, and we discuss the implications of these host captures for the life cycle evolution of Hepatozoon spp. infecting snakes.

The genus Flapocephalus Deshmukh, 1979, is a little-known group of lecanicephalidean cestodes parasitizing cowtail rays (genus Pastinachus Rüppell) mainly in the Indo-Pacific region. Since the erection of the genus, with Flapocephalus trygonis Deshmukh, 1979, as the type species, and the description of a second species, Flapocephalus saurashtri Shinde and Deshmukh, 1979, both from Pastinachus sephen (Fabricius) from India, reports of this genus have been restricted mainly to brief mentions or discussion of its validity and taxonomic placement. More recently, phylogenetic analyses based on molecular sequence data that included specimens of Flapocephalus have supported Flapocephalus as a distinct genus allied with the Polypocephalidae Meggitt, 1924. Limited by the amount of detail provided in the original descriptions, the unavailability of type material, and the lack of a detailed generic diagnosis, we aimed to fully characterize the genus based on newly collected specimens. A total of 38 specimens of Pastinachus, representing 3 of the 5 described species and 1 undescribed species, from throughout the Indo-Pacific region were examined for specimens of Flapocephalus. Worms were prepared for examination with light and scanning electron microscopy and as histological sections. A subset of specimens was included in a phylogenetic analysis based on data for a portion of the 28S rDNA gene. Overall, these specimens were found to include the type species, 4 new species that are described herein (Flapocephalus monostylorchis Hanselman and Jensen n. sp., Flapocephalus capitonis Hanselman and Jensen n. sp., Flapocephalus rudkinorum Hanselman and Jensen n. sp., and Flapocephalus infundibulapex Hanselman and Jensen n. sp.), and 4 putative new species. Flapocephalus trygonis is redescribed from specimens from Pastinachus ater (Macleay) from Sri Lanka, and a neotype is designated. The newly described species are distinct genetically and can be distinguished morphologically from the existing species and one another based on a combination of total length, the shape of the apical organ, and the arrangement of testes and vitelline follicles. A revised diagnosis of the genus and a key to the described species are presented, as is a hypothesis of the interrelationships resulting from a maximum likelihood analysis including 4 of the 5 described species and the 4 putative new species. The presence of 4 glandular, sac-like structures surrounded by scolex proper, with channels that open to the outside at the base of the apical organ, is reported in lecanicephalidean tapeworms for the first time.

In 1995, it was reported that Mohammed and Ramadan (1996, in press) were soon to describe a new species of lizard haemogregarine, Haemogregarina rawashi, in Ptyodactylus hasselquisti from Egypt, but the paper was never published. This name was suppressed because Mohammed and Ramadan violated the "Criteria for Publication" and "What Constitutes Published Work" sections of the International Code of Zoological Nomenclature. A redescription of Ha. rawashi, was restricted only to blood forms, which allowed speculation that the data and visual documentation (photomicrographs, line drawings) of the tissue stages were forever lost. However, here we report collecting P. hasselquisti from South Sinai, Egypt and finding 5/20 (25%) infected with haemogregarine-like blood and tissue (liver) stages. The blood stages were comparable with those in an earlier report from Egypt, the liver stages were comparable with those of other Hepatozoon species, and the newly amplified 18S ribosomal ribonucleic acid sequences were similar to other sequenced Hepatozoon species, justifying the reassignment of Ha. rawashi to Hepatozoon rawashi as reported by others.

A checklist of insects (Arthropoda: Hexapoda: Insecta) that parasitize Mexican bats (Mammalia: Chiroptera) is presented: a total of 100 species grouped in 6 families and 3 orders are registered; these are recorded to infect a total of 69 species of bats in the country. The parasites are bat-flies of the families Nycteribiidae (10 species) and Streblidae (74 species) (Diptera: Hippoboscoidea), bat-bugs of the families Cimicidae (4 species) and Polyctenidae (1 species) (Hemiptera: Cimicoidea), bat-fleas of the family Ischnopsyllidae (10 species), and a chiggerflea of the family Tungidae (1 species) (Siphonaptera: Ceratophylloidea and Pulicoidea).

Members of the copepod family Caligidae are some of the most common parasites of marine fishes. There are 503 recognized species divided into about 30 genera, with 75% of species belonging to the 2 largest genera, Caligus and Lepeophtheirus. More than 30 caligid species are known to cause serious pathologic changes as ectoparasites in marine teleost aquaculture. This study was undertaken to provide a key to the valid genera of Caligidae, to examine their morphology in new detail with confocal laser scanning microscopy, and to review uncertainties concerning boundaries between several genera. There have been several substantial changes to the taxonomy of Caligidae over the last decade: Metacaligus, Sciaenophilus, and Sinocaligus have been synonymized with Caligus and the validity of Midias has been questioned. Here, we formally propose that Midias and Markevichus are junior subjective synonyms of Caligus. In total, we recognize 27 valid genera; provide a key to these genera; present confocal laser scanning micrographs for 25 of the genera, many of which have never been imaged before; and highlight helpful diagnostic features used in the key. We also discuss some concerns regarding the generic boundaries separating Belizia, Caritus, Parapetalus, Parechetus, Pseudechetus, and Synestius from Caligus and those separating Anuretes, Pseudanuretes, and Mappates from Lepeophtheirus.

My journey from mediocre undergraduate with zero interest in parasitology to this year's recipient of the American Society of Parasitologists' Eminent Parasitologist Award has been shaped by serendipity, lucky breaks, and near misses. It is a story beginning with great mentors and then supported for 3 decades by a wonderful cast of students, postdoctoral researchers, research assistants, and collaborators. In this essay, I share that journey to date (it is not quite finished yet!) and some of the research directions I followed along the way. I then present 8 simple tips for early-career parasitologists, distilled from my years of experience in the field, in the hope that they may help others achieve success in research.