The effects of local environmental conditions on the regional distribution, prevalence, and infection intensity of Ergasilus labracis (Copepoda) parasitic on 3-spined stickleback (Gasterosteus aculeatus) was investigated in the Bay d'Espoir region of Newfoundland during May to September of 2015. Environmental conditions (e.g., temperature, salinity, and oxygen) were measured monthly at 7 beach sites distributed through the region. Analysis of environmental characteristics indicated that the area could be divided into 3 zones based on salinity (low-salinity zone: 13.56 ± 0.32 practical salinity units [psu]; medium-salinity zone: 21.11 ± 0.04 psu; high-salinity zone: 29.91 ± 0.32 psu). Ergasilus labracis was found to be the most prevalent parasitic copepod sampled from fish in upper Bay d'Espoir (low-salinity and medium-salinity zones: greater than 75%), but rarely on fish from Hermitage Bay/Connaigre Bay (high-salinity zone: less than 15%). Parasite intensities were highest in the low-salinity zone within Bay d'Espoir at 18–22°C, but decreased significantly in Hermitage Bay/Connaigre Bay (salinity > 20 psu; temperature < 18°C. Decreases in parasite prevalence and increases in mean intensity in July and August for low- and medium-salinity zones are likely due to the appearance of smaller young-of-the-year fish hosting fewer parasites, suggesting that during this period larger adults act as the main reservoirs for infection of young-of-the-year fish >3 cm total body length (September). Our data suggest that G. aculeatus could act as a key amplification source for these parasites and thus may impact adjacent aquaculture sites in the bay.

The morphology of 3 species of Lernaeenicus: Lernaeenicus affixus, Lernaeenicus longiventris, and Lernaeenicus radiatus, mesoparasitic copepods of fishes from the Atlantic coast of North America, is documented. There was significant structural variability in the cephalothorax and holdfast horn complex on the anterior embedded end between individuals in all 3 species. The functional morphology of holdfast structures of the parasites was influenced by the requirements for adequate anchoring in host tissues and was related to the types of tissues and host species infected: attachment directly to bone by individual L. affixus produced lamellae and short, unbranched holdfasts; the hammer-shaped cephalothorax provided with short holdfasts exhibited by members of L. longiventris was found in hard, dense musculature; and elongate, dendritic holdfasts of specimens of L. radiatus were found in soft muscle. Based on morphological characteristics, L. longiventris, L. affixus, and L. radiatus are considered as separate and distinct species even though the latter 2 are similar in size and appendage structure and infect the same species and individual fish hosts. All 3 species are described from specimens in the collection of the United States National Museum.

One hundred coprolites excavated from La Cueva de los Muertos Chiquitos (600–800 CE) in the Rio Zape Valley of present-day Durango, Mexico, were examined for the presence of helminth eggs utilizing standard archaeoparasitological techniques. Eggs of the human pinworm (Enterobius vermicularis) were recovered from 34 of the 100 coprolites examined. Eggs of parasites were photographed and measured before egg concentration values were calculated for each positive sample. Egg concentration values demonstrated an overdispersed pattern of distribution among the samples (66% uninfected, 25% less than 100 eggs/g, 8% between 100 and 500 eggs/g, and 1% more than 500 eggs/g). Given that only 5% of infected hosts in modern cases of human enterobiasis pass the eggs of parasites in their stools, the recovery of E. vermicularis eggs in 34% of the coprolites supports the conclusion that virtually all of the individuals utilizing the site during the coprolite depositional time frame likely were infected with this parasite. These data are discussed in light of other studies of prehistoric human enterobiasis.

While it generally has been accepted that evolutionary pressures may drive parasitic worms to produce many small eggs to overcome the challenges of transmission, recent studies suggest wide variability in reproductive strategies among such worms. Although egg morphometrics and numbers have been reported from many species of Diplostomum, the presence of cryptic species has resulted in uncertainty in morphometric measurements for different life history stages. Here we examine differences between egg characteristics of 2 molecularly delineated species of Diplostomum (Digenea). We investigate whether interspecific differences exist in egg morphometrics or egg number and test if there are intraspecific relationships between size of the egg and the hindbody of adult worms or between size of the egg and fecundity. Egg measurements were obtained from both those collected in feces of experimentally infected ring-billed gulls (Larus delawarensis) and those observed in stained adult specimens of Diplostomum spp. Regardless of the source of measurement, there was a significant difference in the length of the eggs and in egg number between the 2 species, while there was no difference in the widths. Larger worms did not produce significantly larger eggs in either species. Further, egg size was not correlated with the number of eggs present in the stained specimens of either species; smaller eggs were not present in greater numbers. Egg morphometrics can assist in differentiating between these 2 species of Diplostomum. Furthermore, differences in egg sizes and number may reflect other potential differences in life history traits between the 2 species, such as miracidial longevity and infectivity and cercarial output, among others, that still need to be investigated.

Geneiorhynchus gradalis n. sp. (Apicomplexa: Eugregarinida: Actinocephalidae: Actinocephalinae) is described from adults of Ischnura ramburii (Odonata: Zygoptera: Coenagrionidae). Geneiorhynchus gradalis is placed generically by way of its hesperidiform oocysts being released via simple rupture, by the fact that the epimerite is hemispherical and bears many semifalciform spines, and because association occurs late, just prior to syzygy. This species is distinguished from other members of the genus by its distinct oocyst morphometrics (narrowly hesperidiform with distinct bipolar truncations) and by the fact that its epimerite is shallowly toroid, bearing a single anterior row of semifalciform spines and becoming filamentous in mature forms with an absent tumidus. Its diamerite is meager. Herein we describe the new taxon while providing new host and locality records for known actinocephalid gregarines in Louisiana.

Reptiles often serve as hosts for various endo- and ectoparasites including protozoan blood and intestinal parasites. In this study, we report the occurrence of protozoans belonging to three families: Trichomonadidae, Proteromonadidae, and Lankesterellidae, in lizard blood samples. A total of 738 individuals of 4 lizard species (Lacerta agilis, Lacerta viridis, Podarcis muralis, and Zootoca vivipara) captured from 4 European countries (Hungary, Poland, Romania, and Slovakia) were examined. One blood smear obtained in 2008 from L. agilis (Odolanów, Poland) was found to be infected with trophozoites representing three genera: Karyolysus lacazei, Tritrichomonas sp., and Proteromonas sp. Moreover, Proteromonas sp. were detected by molecular methods in another individual of Lacerta agilis exigua (Romania, Vadu), which revealed 100% similarity with the isolate of Proteromonas lacertae isolated from the American Type Culture Collection (GenBank accession number U37108). Sporozoites of Schellackia sp. were detected in blood smears from 2 individuals of L. viridis from Slovakia. Molecular detection revealed the occurrence of Schellackia sp. in 2 individuals, L. viridis (Slovakia) and Lacerta agilis erythronota (Romania) and showed 99% and 90% similarity, respectively, with isolates of Schellackia-like parasites obtained from Lacerta schreiberi (GenBank acc. no. JX984675, JX984674) and Podarcis hispanica (GenBank acc. no. X984676, JQ762306, KJ18938) from Portugal and Spain. This study represents documentation of multiple infections (trophozoites of Karyolysus sp., Tritrichomonas sp., and Proteromonas sp.) detected in a sand lizard from Poland, and the first report of Schellackia in populations of a green lizards (Slovakia) and sand lizards (Romania), as well as the first evidence of Proteromonas sp. from the Romania population of sand lizards.

Members of the digenean genus Gyrabascus have been reported from bats and rodents in Europe, Southeast Asia, North America, and most recently from the marsupial, Monito del Monte (Dromiciops gliroides), in the Argentinian part of Patagonia. We have found digeneans belonging to Gyrabascus in a different species of Monito del Monte (Dromiciops bozinovici) from Chile. This is the first record of Gyrabascus from D. bozinovici and only the second report of Gyrabascus in a marsupial. Although these specimens are morphologically very similar to Gyrabascus dromiciops, we refrained from identifying our material as G. dromiciops due to insufficient specimen quality and the presence of some morphological differences, leaving open the possibility that the specimens from Chile may potentially represent a different, new species. Both morphological characteristics and molecular phylogenetic analysis using partial sequence of nuclear large ribosomal subunit gene (28S) confirmed the systematic position of these specimens and allowed us to discuss their phylogenetic relationships.

Caecincola aubergina n. sp. is described from white crappie (Pomoxis annularis) from B. A. Steinhagen Reservoir in southeastern Texas, U.S.A. Members of C. aubergina n. sp. have an elongate body (5.5–8.8:1 length:width ratio), a multilobed ovary, large vitelline follicles primarily in the hindbody but extending into the forebody, and an oral sucker that is wider than long. The elongate form of the new specimens distinguishes them from all other species in the genus except Caecincola longiscens and Caecincola cookorum. In the former species, vitelline follicles are confined to the hindbody; in the latter species, the body is peanut-shaped and the vitelline follicles are almost entirely in the forebody. This is the eighth species of Caecincola, and a dichotomous key to the species is presented as well.

Allacanthochasmus texanus n. sp. is described from white bass, Morone chrysops, collected from the Trinity River system in southeastern Texas, U.S.A. Specimens of the new species can be distinguished from Allacanthochasmus varius Van Cleave, 1922 by the former's elongate body shape, prominent prepharynx, and tandem testes. The new species is most similar to Allacanthochasmus artus Mueller and Van Cleave, 1932, with which it shares a common body shape, structure of the gonotyl, and distribution and arrangement of most internal structures; the new species differs in having vitelline follicles confined more posteriorly, a gonotyl with more root-like processes, and a smaller number of circumoral spines on the oral sucker. The shape of the circumoral spines in A. texanus n. sp. is highly variable, and the type series includes specimens with spines similar to what described for both A. artus and A. varius. Allacanthochasmus texanus is the third species in the genus from North America, and at this time, all 3 species that are considered valid members of this genus have been described from white bass.

Anenterotrema is a genus of digeneans lacking digestive systems and parasitic in Neotropical bats. We have found a new species of Anenterotrema in silky short-tailed bats (Carollia brevicauda) from Peru. The new Anenterotrema species can be readily differentiated from previously described congeners by a combination of morphological characters. It differs from its morphologically closest cogener, Anenterotrema mesolecitha, in having smaller eggs, a much larger cirrus sac, and in the position of ovary. This is the sixth species of this genus and first to be described from Peru and C. brevicauda.

Twenty-four scincid lizards (spotted forest skink, Sphenomorphus scotophilus) from Peninsular Malaysia were examined for gastrointestinal helminths. Six species of Nematoda, mature individuals of Bakeria schadi, Meteterakis singaporensis, Parapharyngodon maplestoni, Physalopteroides grismeri, and Spinicauda sp., and larvae of Acuariidae gen. sp. were found. Bakeria schadi had the largest number of individuals (38) and the highest prevalence (48%). Larvae of Acuariidae had the greatest mean intensity (6.5 ± 6.4 SD). All represent new host records for S. scotopilus. Our findings indicate that Sphenomorphus scotophilus is parasitized by generalist helminths that also infect other lizards.

One-hundred age-0 walleye Sander vitreus and 100 age-0 yellow perch Perca flavescens collected in September 2015 from Saginaw Bay, Lake Huron, Michigan, U.S.A., were examined for parasites. Five parasite species (Allacanthochasmus sp., Ichthyocotylurus sp., Bothriocephalus cuspidatus, Camallanus oxycephalus, Ergasilus luciopercarum) infected walleye. Ergasilus luciopercarum had the highest prevalence (97%), mean intensity (9.0), and mean abundance (8.7). Ichthyocotylurus sp. and B. cuspidatus each had a prevalence of 73%. Twelve parasite species (Myxobolus neurophilus, Allacanthochasmus sp., Diplostomum sp., Ichthyocotylurus sp., Neascus sp., Crepidostomum sp., B. cuspidatus, Proteocephalus sp., Dichelyne cotylophora, Eustrongylides tubifex, Philometra cylindracea, Ergasilus luciopercarum) occurred in yellow perch. Ichthyocotylurus sp. had the highest prevalence (72%), mean intensity (7.9), and mean abundance (5.7). Proteocephalus sp. had the next highest prevalence (40%). Walleye and yellow perch are new host records for metacercariae of Allacanthochasmus. Saginaw Bay is a new locality record for M. neurophilus in yellow perch and for C. oxycephalus in walleye. This study is the first survey of the parasites of age-0 walleye and age-0 yellow perch in the Great Lakes.

Forty-seven individuals comprising 4 species of birds, Tockus leucomelas, Crecopsis egregia, Turdus smithi, and Bubo africanus; 4 species of mammals, Otolemur crassicaudatus, Gerbilliscus leucogaster, Mus minutoides, and Mus sp.; and 1 species of reptile, Varanus albigularis, all from South Africa were examined for acanthocephalans. Centrorhynchus clitorideus, Mediorhynchus mokgalongi n. sp., Masticophis taeniatus, Moniliformis acomysi, Moniliformis sp., Plagiorhynchus (Prosthorhynchus) cylindraceus, and a putative new genus of the Oligacanthorhynchidae were found. Additional characters of C. clitorideus were described. The new species of Mediorhynchus differs from all congeners by a suite of characters, including a proboscis armature of 125–156 hooks arranged in 24–26 longitudinal rows of 24–26 hooks and 30 rows of 5–6 spines. The putative new genus has a total of 24 hooks arranged in 12 longitudinal rows of 2 hooks. All are new host and locality records.

Pharyngodon frenatusi (Nematoda: Pharyngodonidae) is reported from Brooks’ house gecko, Hemidactylus brookii, and flat-tailed house gecko, Hemidactylus platyurus, from Kirtipur, Nepal. Fifteen samples of H. brookii and 10 H. platyurus were collected in 2014 and examined for helminth parasites. Pharyngodon frenatusi was found in great numbers in the intestines of both hosts. The prevalence of P. frenatusi in H. brookii was 73%, and in H. platyurus, it was 80%. This is the first report, to our knowledge of P. frenatusi reported in house geckoes of Nepal. Hemidactylus platyurus represents a new host record for P. frenatusi.

Between December 2016 and February 2017, 17 Home's hingeback tortoise, Kinixys homeana, confiscated by the United States Fish and Wildlife Service and originating from the Republic of Benin, Africa, had their feces examined for coccidian and helminth parasites. No coccidia were passing in their feces; however, 40 individual specimens of the nematode Atractis africana Ortlepp, 1933, were found in 1 tortoise as well as its larvae in another tortoise. In addition, trophozoites of the ciliate, Nyctotherus cordiformis were found in 2 K. homeana. This is the first report of A. africana from this host as well as a significant geographic record. Importantly, this is the initial helminth reported from K. homeana and the first time this nematode has been reported since the original description more than 80 yr ago.