Full Mitochondrial Genome and Nuclear 18S rDNA Sequences Refine the Taxonomic Placement of Choleoeimeria taggarti n. comb. from the Prostate of Antechinus flavipes (Yellow-Footed Antechinus).

An unusual coccidian parasite was described previously from the prostate of a male Antechinus flavipes (family: Dasyuridae; common name: yellow-footed antechinus). Morphometrics and a partial nuclear 18S small subunit rDNA (18S rDNA) sequence were used to assign this parasite to the genus Eimeria; it was named Eimeria taggarti. We generated full nuclear 18S rDNA and mitochondrial genome sequences from this parasite and used the newly completed 18S rDNA and mitochondrial cytochrome c oxidase subunit I (COI) sequences to perform a more in-depth phylogenetic analysis. The parasite clustered closely with Choleoeimeria spp. and Acroeimeria spp. infecting herptiles in a well-supported clade that was the sister lineage to the Eimeriidae sensu stricto. The mitochondrial genome of this parasite contained 2 inverted segments compared to mitochondrial genomes from parasites in the Eimeriidae sensu stricto (i.e., Stieda body-possessing coccidia with 4 dizoic sporocysts); this mitochondrial genome arrangement was shared with the only Choleoeimeria species for which sequence data were available publicly. Examination of histological preparations and TEM images uncovered bivalvate sporocysts and otherwise confirmed previously described morphological features of the parasite. Based on our phylogenetic analyses and histological observations, we propose the generic reclassification of E. taggarti to Choleoeimeria taggarti n. comb.

Newly Described Coccidia Goussia bayae from White Perch Morone americana: Morphology and Phylogenetics Support Emerging Taxonomy of Goussia within Piscine Hosts.

In March and April 2016, 150 white perch ( Morone americana) were collected from various localities in Chesapeake Bay and examined for coccidia. A previously undescribed species of coccidia was observed in the hepatic bile ducts and gallbladder of all white perch (100%) examined. We describe this species using morphological characteristics, histology, and gene sequences of the small-subunit ribosomal DNA ( rDNA), large-subunit rDNA, and mitochondrial genes cytochrome oxidase 1 ( COI), cytochrome oxidase b ( Cytb), and cytochrome oxidase 3 ( COIII). Oocysts of Goussia bayae n. sp. were subspherical with a single-layered smooth wall and measured (length [L] × width [W]) 26.2 × 21.8 µm, with a L/W ratio of 1.2. A micropyle was present but a micropyle cap, polar granules, and oocyst residuum were absent. Each oocyst contained 4 sporocysts that were ellipsoidal and measured (L × W) 12.6 × 7.8 µm, with a L/W ratio of 1.6. A pair of sporozoites was present, but sporocysts lacked a Stieda body and residuua. Meronts and gamonts were epicellular in biliary epithelial cells and oocysts were coelozoic in hepatic and common bile ducts and gallbladder. This is the first report of Goussia spp. from white perch and the first mitochondrial DNA sequence reported from a Goussia species. Phylogenetic analysis indicates basal placement of G. bayae to Eimeriidae, Choleoeimeria, and Sarcocystidae.

The Coccidia (Apicomplexa: Eimeriidae) of Legless Lizards (Squamata: Lacertoidea: Amphisbaenia) of the World.

Legless lizards (Amphisbaenia) belong to a group of mostly legless squamates that include about 196 species. One genus ( Bipes) retains a pair of forelimbs, but all other 19 genera in the clade are limbless. They are widely distributed, occurring in the Middle East and the Caribbean and nearly all of the major continents (except Australia). Only 2/6 (33%) families, 3/20 (15%) genera, and 4/195 (2%) species in the Amphisbaenia clade of the Sauria have been examined for coccidia and 8 coccidia species are now known. Here, we summarize information on the 8 species of coccidia (3 Choleoeimeria, 1 Eimeria, 4 Isospora) reported from legless lizards of the world. In addition, Eimeria amphisbaeniarum Huntington, Cisper, Smith, Powell, Parmerlee Jr., and Lathrop, 1996, is placed in the genus Choleoeimeria. We speculate that another 380 intestinal coccidia infecting this unique reptilian lineage wait to be discovered.

Morphological and molecular characterization of Choleoeimeria pogonae n. sp. coccidian parasite (Apicomplexa: Eimeriidae, 1989, Paperna and Landsberg) in a western bearded dragon (Pogona minor minor).

A new species, Choleoeimeria pogonae n. sp. is described from a Western bearded dragon (Pogona minor minor) in Western Australia. Sporulated oocysts (n = 48) were cylindroidal in shape. Oocyst length, 27.0 (26.0-28.3) µm, oocyst width, 15.2 (14.0-16.5) µm, oocyst length/width ratio (L/W) 1.8 (1.6-1.9), each with 4 sporocysts (Eimeria-like) and a polar granule, but lacking a micropyle and oocyst residuum. Sporocysts are ovoidal in shape, sporocyst length, 10.0 (9.0-11.0) µm, sporocyst width 8.5 (7.0-9.5) µm, sporocyst L/W ratio, 1.2 (1.1-1.3). Stieda, substieda and parasubstieda bodies were all absent. Molecular analysis was conducted at the 18S rRNA and cytochrome c oxidase I (COI) loci. Phylogenetic analysis of 18S sequences revealed that C. pogonae n. sp. grouped together with another four Choleoeimeria spp. and exhibited 99.1%-99.4% genetic similarity. At the COI locus, C. pogonae n. sp. was in an independent clade and had the highest similarity (80.4%) to Eimeria cf. mivati from a chicken (Gallus gallus domesticus). According to the morphological and molecular data, this isolate is a new species of coccidian parasite. This study further supports the taxonomy of Choleoeimeria spp. as a new genus based on molecular phylogenetic analysis.

Phylogeny, Morphology, and Metabolic and Invasive Capabilities of Epicellular Fish Coccidium Goussia janae.

To fill the knowledge gap on the biology of the fish coccidian Goussia janae, RNA extracted from exogenously sporulated oocysts was sequenced. Analysis by Trinity and Trinotate pipelines showed that 84.6% of assembled transcripts share the highest similarity with Toxoplasma gondii and Neospora caninum. Phylogenetic and interpretive analyses from RNA-seq data provide novel insight into the metabolic capabilities, composition of the invasive machinery and the phylogenetic relationships of this parasite of cold-blooded vertebrates with other coccidians. This allows re-evaluation of the phylogenetic position of G. janae and sheds light on the emergence of the highly successful obligatory intracellularity of apicomplexan parasites. G. janae possesses a partial glideosome and along with it, the metabolic capabilities and adaptions of G. janae might provide cues as to how apicomplexans adjusted to extra- or intra-cytoplasmic niches and also to become obligate intracellular parasites. Unlike the similarly localized epicellular Cryptosporidium spp., G. janae lacks the feeder organelle necessary for directly scavenging nutrients from the host. Transcriptome analysis indicates that G. janae possesses metabolic capabilities comparable to T. gondii. Additionally, this enteric coccidium might also access host cell nutrients given the presence of a recently identified gene encoding the molecular sieve at the parasitophorous vacuole membrane.

A new caryosporan and eimerian (Apicomplexa: Eimeriidae) from green anoles, Anolis carolinensis (Sauria: Dactyloidae), from Arkansas and Louisiana, with a summary of the coccidia of Dactyloidae.

Between April 2012 and September 2013, feces from 18 green anoles, Anolis carolinensis from Arkansas (n = 14), Louisiana (n = 1), and Oklahoma (n = 3) were examined for coccidia. Two species of coccidians were found, including a new caryosporan and a new eimerian. Oocysts of Caryospora natchitochesensis n. sp. from a single A. carolinensis from Louisiana were subspheroidal to ovoidal with a smooth, yellow-to-brown-pigmented, bilayered wall of equal thickness (∼0.3-0.7) and measured (L × W) 13.1 × 12.3 µm, with a length/width (L/W) ratio of 1.1. A micropyle and oocyst residuum were absent, but a polar granule was present. Sporocysts were ovoidal and measured 10.1 × 7.4 µm, L/W was 1.4. A Stieda body (∼1.0 µm) was present, but substieda and parastieda bodies were absent. The sporocyst residuum was composed of dispersed granules or globules among sporozoites. Oocysts of Eimeria robisoni n. sp. from 1 of 12 (8%) green anoles from Arkansas were ellipsoidal with a smooth, unilayered wall (∼0.4-0.5) and measured (L × W) 14.5 × 10.5 µm, with L/W ratio of 1.4. A micropyle and oocyst residuum were absent, but 1-4 (usually 2) polar granules were present. Sporocysts were subspheroidal to ovoidal and measured 5.8 × 4.9 µm, L/W was 1.2. Stieda, substieda, and parastieda bodies were absent. The sporocyst residuum was composed of dispersed granules between sporozoites. None of the anoles from Oklahoma was found to be passing oocysts. This is the second time an eimerian and a caryosporan have been reported from green anoles. A summary of the coccidians of lizards of the family Dactyloidae is provided, with special emphasis on the Anolis of the United States.

A new species of Caryospora (Apicomplexa: Eimeriidae) from the bald eagle, Haliaeetus leucocephalus (Accipitriformes: Accipitridae), from Kansas.

Between March 1989 and February 1994, 4 bald eagles ( Haliaeetus leucocephalus ) from various localities in Kansas were examined for coccidia. One (25%) of the bald eagles was found to be passing an undescribed species of Caryospora in its feces. Oocysts of Caryospora hanebrinki n. sp. are ellipsoidal to ovoidal with a bilayered wall and measure 48.1 × 42.1 µm with a shape index of 1.2. A micropyle, oocyst residuum, and polar granule were absent. Sporocysts are spheroidal, 24.8 µm wide. Stieda, substieda, and parastieda bodies were absent; a spheroidal sporocyst residuum is present; it measures 17.5 µm and is composed of many intact homogenous globules with a few dispersed in a loose spiral around the sporocysts. This is the first caryosporan documented from the bald eagle and is the largest known Caryospora from raptors.

A new species of Caryospora (Apicomplexa: Eimeriidae) from the sharp-shinned hawk, Accipiter striatus (Aves: Accipitriformes).

An injured juvenile sharp-shinned hawk, Accipiter striatus Vieillot, 1807 (Aves: Accipitriformes), housed and treated at the College of Veterinary Medicine Teaching Hospital at Kansas State University, Manhattan, Kansas, USA, was found to be passing oocysts of an undescribed species of Caryospora in its feces. Sporulated oocysts of Caryospora petersoni n. sp. were subspherical, with a bilayered wall, and they measured 43.1 × 39.8 µm; micropyle, oocyst residuum, and polar granule were absent. Sporocysts were subspherical to spherical, 23.4 × 23.3 µm; Stieda, substieda, and parastieda bodies were absent, but a spherical sporocyst residuum was present as a compact mass, ~15.1 µm wide, composed of many homogeneous globules. The new species represents the first caryosporan documented from this species of hawk.

A new species of Choleoeimeria (Apicomplexa: Eimeriidae) from Meller's chameleon, Trioceros melleri (Sauria: Chamaeleonidae).

A captive specimen of Meller's chameleon, Trioceros melleri (Gray), originally from Tanzania and housed at the Oklahoma City Zoological Park Herpetarium, Oklahoma County, Oklahoma, was found to be passing an undescribed species of Choleoeimeria in its feces. Oocysts of Choleoeimeria steveuptoni n. sp. were cylindroidal, 38.5 × 17.8 (36-42 × 17-19) µm with a bilayered wall and a shape index (length/width) of 2.2. A micropyle and oocyst residuum were absent, but a fragmented polar granule was often present. Ovoidal sporocysts were composed of 2 valves joined by a suture and measured 11.3 × 9.1 (11-12 × 9-10) µm; shape index of 1.3. Stieda, sub-Stieda, and para-Stieda bodies were absent. The sporocyst residuum consists of multiple globules dispersed along the perimeter of the sporocyst and between sporozoites. Sporozoites were elongate, 13.1 × 2.9 (12-15 × 2.6-3.2) µm with an elongate posterior refractile body. The new species represents the second coccidian documented from this lizard.

A new species of Caryospora (Apicomplexa: Eimeriidae) from the flathead snake, Tantilla gracilis (Ophidia: Colubridae), in southeastern Oklahoma.

A single flathead snake, Tantilla gracilis , collected in early October 2010 from Choctaw County, Oklahoma, was found to harbor an undescribed species of Caryospora . Oocysts of Caryospora choctawensis n. sp. were spherical to subspherical, 15.8 × 15.0 (14-18 × 14-16) µm, with a thick, bilayered wall and a shape index (length∶width) of 1.1. A micropyle and an oocyst residuum were absent, but prominent Stieda and bubble-like sub-Stieda bodies were present as well as a bilobed polar granule near the oocyst wall. Sporocysts were ovoidal, 10.8 × 9.0 (10-12 × 8-9) µm, with a shape index of 1.2. The sporocyst residuum was spherical and composed of a cluster of granules often membrane-bound. This is the second time a caryosporan species has been reported from T. gracilis but the first coccidian ever described from a reptilian host in Oklahoma. Additional T. gracilis from Arkansas (n  =  6), Oklahoma (n  =  1), and Texas (n  =  7) were examined, and a single specimen from Newton County, Arkansas harbored Caryospora gracilis Upton, McAllister, Trauth, and Bibb, 1992 , previously reported from T. gracilis collected in Arkansas and Texas.

Goussia Labbé, 1896 (Apicomplexa, Eimeriorina) in Amphibia: diversity, biology, molecular phylogeny and comments on the status of the genus.

We provide new data on morphology, host specificity, life history, pathology and phylogeny of the coccidian genus Goussia in European anurans. Divergence in the SSU rDNA sequences (3-4%) of three Goussia isolates from three anuran hosts suggests that the isolates represent three distinct species. The isolate from Pelophylax kl. esculentus was determined as Goussia neglecta. The isolates from Rana dalmatina and Rana temporaria are considered conspecific and are, on the basis of host specificity, light microscopical, ultrastructural, and molecular phylogenetic data, described as a new species, Goussia noelleri. The new Goussia species from Bufo bufo remains unnamed. During the host's metamorphosis the infection disappears, however, oocysts are retained in the liver of post-metamorphic frogs. Molecular phylogenetic analysis showed that anuran-host Goussia form a well-supported monophyletic clade, which together with a clade represented by piscine Goussia metchnikovi, constitute basal lineages of the Eimeriidae. The two lineages show polytomy, likely reflecting undersampling of the basal eimeriid taxa. Goussia janae represents a distinct lineage, sister to the clade containing the other eimeriorinid taxa, suggesting a paraphyly of the genus Goussia. The identity of G. neglecta, the status of the genus Goussia, the presence of cryptic species in anuran-host Goussia and their ecological peculiarities are discussed.

Ultrastructural review of Choleoeimeria spp., a coccidium infecting the gall-bladder epithelium of reptiles.

Choleoeimeria Paperna and Landsberg, 1989 is a reptile coccidium with unique features. Its endogenous development occurs in the cells of the bile epithelium. Its host cell while becoming hypertrophic emerges above the epithelial surface. The following species studied by electron microscopy: C. alloagamae Paperna, 2007 from Agama sp. West Africa; C. allogehyrae Paperna, 2007 from Gehyra australis and C. heteronotis Paperna, 2007 from Heteronotia binoei, from Australia, and C. pachydactyli Paperna and Landsberg, 1989 from Pachydactylus capensis from South Africa. The fine structure of the respective endogenous stages is fairly uniform. The host-cell hypertrophy coincides with a drastic depletion of the microvilli, their junction zone with the underlying cell extends into numerous long and fine membranal out-folds. The PV of all infected cells is filled with typical round granular particles. Young meronts undergo binary fission. The differentiating microgamont develops an expanded multilobed body. Macrogamont's organelles include type 1 and type 2 wall forming bodies, canaliculi and granular bodies, suspected to be the precursors of the sporozoites refractile bodies. The oocyst wall forms from 4 wall-membranes consolidating over the zygote plasmalemma.

New species of Choleoeimeria (Apicomplexa: Eimeriidae), coccidia of bile-bladders of reptiles, illustrating a multiplicity of host cell-parasite interrelations.

Oocyst characteristics and histological features of the endogenous development of bile-bladder coccidia of the genus Choleoeimeria Paperna and Landsberg, 1989 are described and the main features for species differentiation are discussed for the following new species: C. allogamae n. sp. from Agama sp., Cameroon, West Africa; C. allogehyrae n. sp. from Gehyra australis, Magnetic Island (type) and mainland N Queensland, Australia; C. boulii n. sp. from Gehyra variegata, SW Queensland, Australia; C. calotesi n. sp. from Calotes mystaceus, Xiang-Mai, Thailand; C. heteronotis n. sp. from Heteronotia binoei, N Queensland, Australia; C. lygosomis n. sp. from Lygosoma buringi, Kon-Kaen, Thailand; C. sylvatica n. sp. from Carlia rhomboidalis, N Queensland, Australia, and C. xiangmaii n. sp. from Hemidactylus frenatus, Xiang-Mai, Thailand. Oocyst characteristic of Choleoeimeria are also reported from Oedura castelnaui, N Queensland. The described species demonstrate a diversity of associations with the bile-bladder epithelial lining, from a single parasite in a single hypertrophic host cell to multiple infections inducing the hypertrophied cells to form stratified layers, or merge into branched clumps.

Ultrastructural aspects of hepatic coccidiosis caused by Goussia lusca n. sp. (Apicomplexa: Coccidia) infecting Trisopterus luscus (Gadidae) from the NE Atlantic Ocean.

Goussia lusca n. sp. is described from the liver of pouting Trisopterus luscus from the NE Atlantic Ocean in Ibero-Atlantic Portuguese and Spanish waters. Mature oocysts were 31.7 (28.8 to 35.4) microm in diameter. Each oocyst contained 4 ellipsoidal sporocysts arranged in an aleatory position, and measuring approximately 13.7 x 9.2 microm. Each sporocyst contained 2 sporozoites. Ultrastructurally, the sporocyst wall consisted of a dense inner layer 115 nm thick, transversely striated, regularly intercalated by thin grooves with electron-lucent spaces, and separated from the outer layer by a thin, light (electron-lucent) space. The outer layer was multilamellated and consisted of parallel dense bands alternating with light spaces. These lamellae formed filamentous extensions of the wall. The dehiscence suture, a characteristic feature of the genus, was present in the sporocysts. No external clinical signs were observed in the host fish. Parasites observed in the liver tissue were often enveloped in a yellowish-brown matrix, generally known as 'yellow bodies'. Sometimes sporocysts were observed in direct contact with the liver cells. Parasites in degeneration and aggregations of amylopectin granules were frequently observed surrounded by host inflammatory cells. In severe infections, we observed large agglomerations of oocysts encapsulated by layers of concentrically arranged connective tissue forming large granulomas, which caused significant replacement of the host liver parenchyma by the parasite.

Molecular characterization of isosporoid coccidia (Isospora and Atoxoplasma spp.) in passerine birds.

Prevalence and disease caused by isosporoid coccidia in passerine birds are well recognized, but confusion about the life cycles of the parasites has led to taxonomic inconsistencies. In this study, we characterized segments of the chromosomal small and large-subunit ribosomal RNA (rRNA) genes of coccidial parasites from 23 species of passerine birds, as well as heat shock protein 70, apicoplast rRNA, and chromosomal 5.8s rRNA genes from a subgroup of these animals, and we correlated genetic data with morphologic findings for different parasite developmental stages, host phylogeny, and overall taxonomic relations within the phylum Apicomplexa. Our findings indicate that isosporoid coccidia of passerine birds are monophyletic but exhibit substantial diversity, with most avian species having one or several unique parasite lineages that underwent synchronous speciation with their hosts, interrupted by sporadic episodes of lateral transmission across species and families. Molecular analyses support a homoxenous life cycle, with sexual forms occurring chiefly in the intestines and asexual merozoites present systemically. Rarely, extraintestinal sexual stages can occur. The passerine coccidia are genetically most closely related to species of Eimeria rather than Isospora. We suggest that these parasites, whether identified from blood merozoite stages or fecal oocysts, be provisionally grouped as a homogeneous clade of individual species in a single taxon and formally named when reliable criteria allowing reclassification of related genera in the suborder Eimeriina are clarified.

Ultrastructure of Goussia cruciata (Apicomplexa: Coccidia) infecting the liver of horse mackerel, Trachurus trachurus (L.), from Ibero-Atlantic waters.

The ultrastructure of developmental stages of Goussia cruciata and the pathology they cause in the liver of Trachurus trachurus (Teleostei: Carangidae) caught off the Galician (North-West Spain) and Portuguese North Atlantic coasts are described. Each oocyst contained four ellipsoidal sporocysts, with two sporozoites. The sporocyst wall consisted of a thick and dense inner layer with transverse striations and a multi-lamellated outer layer formed by parallel dense internal bands alternating with lighter areas. The lamellae formed filamentous extensions of the wall. The sporocyst wall striation period was smaller than that observed in G. clupearum, which has a similar habitat. The dehiscence suture, characteristic of the genus, was present in the sporocysts of G. cruciata. The sporocysts were arranged in a symmetrical and characteristic cross shape. A large number of sporocysts with sporozoites were observed in direct contact with host liver cells. No macroscopic lesions were observed. In heavily infected fish, aggregations of oocysts were often enveloped in a 'yellow body' composed of amylopectin granules derived from the parasite and necrotic or aggregated host cells. Degenerating parasites were frequently observed in liver tissue. Host inflammatory cells were accumulated near some oocysts. The ultrastructure of the parasite, together with its strict host specificity, confirmed G. cruciata as a separate and valid species.

Descriptions of six new species of Caryospora (Apicomplexa: Eimeriidae) from Guatemalan snakes (Serpentes: Colubridae and Viperidae).

One hundred and seventy snakes were collected in Guatemala and examined for coccidia. Of these, 8 individuals representing 6 host species were positive for Caryospora spp., 6 of which are described as new species. Sporulated oocysts of Caryospora bothriechis n. sp. from Bothriechis aurifer are spheroidal to subspheroidal, 12.7 x 12.5 (12-14 x 12-13) microm, with a length/width (L/W) ratio of 1.0; they lack a micropyle (M) or oocyst residuum (OR), but 1 large polar granule (PG) is usually present. Sporocysts are ovoidal, 9.0-7.5 (8-10 x 7-8) microm, and have a L/W ratio of 1.2, and a Stieda body (SB) and sporocyst residuum (SR). Oocysts of Caryospora coniophanis n. sp. from Coniophanes imperialis are spheroidal to subspheroidal, 18.8 x 18.1 (17-20.5 x 16-20) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.2 x 9.4 (12-15 x 8-10) microm with a L/W ratio of 1.4, and a SB, substieda body (SSB), and SR. Oocysts of Caryospora conophae n. sp. from Conophis lineatus are spheroid to subspheroidal, 20.4 x 19.5 (17-26 x 17-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.1 x 9.8 (11-15 x 8-11) microm with a L/W ratio of 1.3 and a SB, SSB, and SR. Oocysts of Caryospora guatemalensis n. sp. from Lampropeltis triangulum are spheroidal to subspheroidal, 23.9 x 23.2 (20-27 x 20-26) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.4 x 10.6 (13-18 x 9-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora mayorum n. sp. from Conophis lineatus are spheroidal to subspheroidal, 25.6 x 24.4 (24-27 x 24-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 16.3 x 11.9 (16-18 x 11-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora zacapensis n. sp. from Masticophis mentovarius are spheroidal to subspheroidal, 22.5 x 21.8 (19-25 x 18-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.6 x 11.4 (11-16 x 10-13) microm, with a L/W ratio of 1.3 and a SB, SSB, and SR.

Echis carinatus (Serpentes: Viperidae) as a new host for Caryospora maxima (Apicomplexa: Eimeriidae) in Saudi Arabia.

Caryospora maxima is redescribed from the intestinal contents of the viperid snake, Echis carinatus collected from Gazan area in the southern region of Saudi Arabia. This report represents a new host and geographic location for the parasite. Sporulated oocysts of this coccidian are spherical to subspherical, 42.8 x 41.2 (40.3-45.9 x 39.6-43.8) microm, with smooth brownish-yellow bilayered wall, 1.9 (1.5-2.3) microm. thick. Micropyle and oocyst residuum are absent. Some oocysts had a small polar granule. Sporocysts are broadly ellipsoid, 22.1 x 16.8 (21.0-23.3 x 15.5-17.4) microm., with a prominent stieda and substieda bodies. Sporocyst residuum is present consisting of many granules in compact mass. Sporozoites are banana-shaped, each with two refractile globules. Oocyst measurements were similar to those reported from Psammophis schokari in Jordan. Except for the presence of a spherical polar granule, the oocyst morphology was identical to the original description of C. maxima.

The phylogeny of Goussia and Choleoeimeria (Apicomplexa; Eimeriorina) and the evolution of excystation structures in coccidia.

The phylogenetic relationships of Goussia janae and Choleoeimeria sp. were analyzed using the small subunit ribosomal RNA gene (SSU rDNA). This is a first attempt to study the molecular phylogeny of coccidian genera parasitizing strictly poikilotherm hosts. The biliary Eimeria-like coccidia of reptiles classified into the genus Choleoeimeria form a sister clade to the family Eimeriidae, which confirms the separate generic status of the genus Choleoeimeria. The position of Goussia is less robustly resolved, since it forms a trichotomy with the Eimeriidae and Sarcocystidae, or alternatively constitutes the earliest branch of the coccidian lineage. Morphological similarities, namely the extracytoplasmic location of the endogenous stages, and the presence of sutures in the sporocyst wall are discussed in the context of the traditional classification of eimeriids. In contrast to the morphology-based systematics, the monophyly of Goussia and Choleoeimeria is not supported by the SSU rDNA data.

Fine structure of sporogonic stages of Goussia clupearum (Apicomplexa: Eimeriidae) in the liver of infected fish (Belone belone L.), using light and electron microscopy.

A coccidian species, Goussia clupearum (L.) is reported to parasitize the liver of a new host, Belone belone (Teleostei: Belonidae), caught on the Atlantic coast at the north of Portugal. The parasitophorous vacuole containing oocysts was attached to the host's liver cells. Spherical oocysts (approximately 21.2 microm diameter), each containing four ellipsoidal elongated sporocysts (10.5 x 6.3 microm), were enclosed in the parasitophorous vacuole. Each sporocyst contained two sporozoites. The micropyle was absent, but a polar granule (without Stieda body) was present. Each sporozoite possessed four refractile bodies. During sporoblastogenesis and sporogenesis, one or two dense polar bodies were found within the oocysts. They were composed of a dense homogeneous core, surrounded by a ring of dense granular material. On occasion, we observed some sporocysts in direct contact with host cells. This paper describes the morphology and ultrastructural details of the oocysts, sporocysts and sporozoites of G. clupearum. This species seems to represent the only coccidium described in fish from this Atlantic coast.