Species of coccidia (Apicomplexa: Eimeriidae) in shrews from Alaska, U.S.A., and northeastern Siberia, Russia, with description of two new species

Fecal samples (n = 636) from 10 species of shrews collected in Alaska (n = 540) and northeastern Siberia (n = 96) were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five distinct oocyst morphotypes were observed. Three types were consistent with oocysts of previously recognized coccidia species from other shrew hosts. These were Eimeria inyoni, E. vagrantis, and Isospora brevicauda, originally described from the inyo shrew (Sorex tenellus), dusky shrew (S. monticolus), and northern short-tailed shrew (Blarina brevicauda), respectively. We found 5 new host records for E. inyoni, 3 for E. vagrantis, and 3 for I. brevicauda. The 2 additional oocyst morphotypes, both from the tundra shrew (Sorex tundrensis), are putative new species. Sporulated oocysts of Eimeria beringiacea n. sp. are subspheroidal, 17.7 x 15.6 microm (14-24 x 13-20 microm) with a length (L)/width (W) ratio of 1.1 (1.0-1.4); these lack a micropyle (M), an oocyst residuum (OR), and a polar granule (PG). Sporocysts are ellipsoidal, 10.3 x 6.1 microm (7-14 x 4-8 microm), with a L/W ratio of 1.7 (1.3-2.3) and have a Stieda body (SB), Substieda body (SSB), and sporocyst residuum (SR). Oocysts of Eimeria tundraensis n. sp. are spheroidal to subspheroidal, 24.8 x 23.5 microm (23-26 x 22-25 microm), with a L/W ratio of 1.1 (1.0-1.2); these lack a M and OR, but a single PG is present. Sporocysts are elongate ellipsoidal, 15.4 x 8.3 microm (13-17 x 7-9 microm), with a L/W ratio of 1.9 (1.4-2.1) and have a SB, SSB, and SR.     

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.     

Three new species of Eimeria (Apicomplexa: Eimeriidae) from the silvery mole rat Heliophobius argenteocinereus Peters, 1846 (Rodentia: Bathyergidae) from Malawi

Three species of Eimeria Schneider are described from feces of the African bathyergid rodent, Heliophobius argenteocinereus, from Malawi. Oocysts of Eimeria heliophobii n. sp. are broadly ellipsoidal; 27.9 (22-31) x 22.3 (18-24.5) microm with a brownish, heavily pitted oocyst wall, and vacuolar oocyst residuum. Sporocysts are oval, 12.8 (12-14) x 8.4 (8-9) microm with Stieda and substieda bodies. Eimeria nafuko n. sp. has subspherical oocysts; 15.5 (15-16) x 12.8 (12-13) microm with a smooth, colorless oocyst wall. Sporocysts are oval, 9.2 (9-10) x 5.3 (5-6) microm, with a small Stieda body; the substieda body is not visible. Oocysts of Eimeria yamikamiae n. sp. are broadly ellipsoidal to subspherical; 20.8 (19-22) x 17.5 (15.5-19) microm, with slightly yellowish, very faintly pitted oocyst wall. The majority of oocysts contained a single spherical vesicular oocyst residuum and numerous very small granules. Sporocysts are oval, 10.7 (10-11) x 6.8. (6-7) microm, with a dome -like Stieda body and a subspherical to lentil-like substieda body. Typically, infected rodents shed oocysts of more than 1 species of Eimeria.     

Eimeria auratae n. sp. (Apicomplexa: Eimeriidae) infecting the lizard Mabuya aurata in Saudi Arabia

Eimeria auratae n. sp. was described from the gall bladder of the lizard Mabuya aurata collected at Al-Hofuf village, eastern region, Saudi Arabia. Morphology of sporulated as well as non-sporulated oocysts were studied. Sporulated oocysts were ellipsoidal 22-31.5x13.5-21.8 (27.7x18.5) microm with smooth brownish-yellow bilayered wall, 1.1 (0.9-1.3) microm. Micropyle, polar granule and oocyst residuum were absent. Sporocysts were ellipsoidal 10.5-12.8x7.5-9 (11.8x8.5) microm. Sporocyst residuum was present but Stieda body was absent. Sporozoites were crescent-shaped, blunt at one end and slightly tapered at the other. Eimeria species from Scincidae were compared.     

Six new species of coccidia (Apicomplexa: Eimeriidae) from East African chameleons (Sauria: Chamaeleonidae)

Coprological examination of 83 East African chameleon specimens revealed 32.5% prevalence of coccidian parasites. Six species are described as new: Eimeria tilburyi n. sp. from Chamaeleo jacksonii has cylindrical oocysts, 28.9 (26-33) x 16.0 (14-18) microm and occasionally a small polar granule. Sporocysts are oval to ellipsoidal, 10.6 (9-12) x 7.2 (6-8) microm, without Stieda and substieda bodies; endogenous stages were found in the gall bladder. Oocysts of Eimeria largeni n. sp. from Chamaeleo gracilis are broadly cylindrical, 31.2 (29.5-34) x 19.3 (18.5-20) microm, with 1-3 polar granules. Sporocysts are oval, 10.2 (10-11) x 7.6 (7-8.5) microm, without Stieda and substieda bodies. Eimeria bohemii n. sp. from Chamaeleo melleri has cylindrical oocysts, 25.0 (24-26) x 14.0 (13-15) microm, without a polar granule. Sporocysts are broadly oval, 9.4 (9-10) x 6.5 (6-7) microm, without Stieda and substieda bodies. Isospora wildi n. sp. from Chamaeleo dilepis has subspherical to broadly oval oocysts, 25 (22-28) x 21.4 (18-24) microm, with a smooth wall 1 microm thick. Sporocysts are broadly oval to ellipsoidal, 12.3 (12-13) x 9.7 (9-10) microm, with Stieda and substieda bodies. Oocysts of Isospora necasi n. sp. from C. melleri are subspherical to broadly oval, 26.6 (21-30) x 24.3 (20-27) microm, with a velvetlike wall 2 microm thick. Sporocysts are broadly ellipsoidal, 12.8 (12-14) x 9.8 (9-10) microm, with slightly pointed end and with Stieda and substieda bodies. Oocysts of Isospora munriyu n. sp. from C. jacksonii are spherical to subspherical, 23.6 (21.5-25) x 21.9 (21-23) microm, with a finely granulated wall 1.5 microm thick. Sporocysts are broadly ellipsoidal, 12.4 (12-13) X 8.7 (8-10) microm, with Stieda and substieda bodies.     

Two new species of Eimeria (Apicomplexa: Eimeriidae) from Asian geoemydid turtles Kachuga tentoria and Melanochelys trijuga (Testudines: Geoemydidae)

Coprological examination of ten Pink-ringed tent turtles Kachuga tentoria circumdata, recently imported from India, and three Burmese black turtles Melanochelys trijuga edeniana, imported from Myanmar, revealed the presence of two new species of Eimeria. Oocysts of Eimeria kachua n. sp. from K. t. circumdata are broadly oval to subspherical, 15.3 (13-18) x 13.9 (12-16) microm, with polar granule and subspherical oocyst residuum. Sporocyst elongatelly oval to spindle-shaped, 8.7 (7.5-10) x 4.9 (4-6) microm, with a knoblike Stieda body, covered with fine membranous cupola-like structures. Thin walled oocysts of Eimeria patta n. sp. from M. t. edeniana, have an irregular shape, influenced by the position of sporocysts, frequently with lobular irregularities, 12.6 (11-16) x 9.1 (7.5-12) microm. Sporocysts are oval to ellipsoidal, 5.8 (5-7) x 4.2 (3.5-5) microm.     

Eimeria gozaishoensis n. sp. from the Formosan serow (Capricornis crispus swinhoei)

Eimeria gozaishoensis n. sp. was found in the Formosan serow (Capricornis crispus swinhoei). The oocysts were ovoid, 29.41 +/- 0.58 x 20.77 +/- 0.41 microns with a bilayered wall. A micropyle and micropylar cap were observed, but a polar granule and oocyst residuum were absent. Sporocysts were ovoid, 11.78 +/- 0.30 x 7.60 +/- 0.31 microns, with sporocyst residuum and Stieda body. The new species differs from other known species of the genus by the morphology of oocysts and that domestic goats apparently could not be infected. The sporulation time was 6 to 7 days.     

Redescription and new host record of Eimeria serbica from the Caucasian tree squirrel, Sciurus anomalus, from Turkey

Fecal samples from 20 Caucasian tree squirrels, Sciurus anomalus (Gmelin, 1778) Güldenstaedt, 1785, were collected in Turkey during February and March, 2004, and all 20 were infected with a single species of coccidia, Eimeria serbica. Sporulated oocysts are ellipsoidal, 27.5 x 17.5 (21-34 x 15-20) with a length:width ratio (L/W) of 1.6 (1.4-1.8); they lack a micropyle and oocyst residuum, but 0-2 polar granules may be present. Sporocysts are ellipsoidal, 11.9 x 6.9 (10.5-14 x 6-7.5) with a L/W of 1.7 (1.5-2.1); a Stieda body and sporocyst residuum are present.     

Eimeria species from the European pond turtle, Emys orbicularis (Reptilia: Testudines), in Galicia (NW Spain), with description of two new species

Parasitological examination of feces from 44 Emys orbicularis from Galicia (NW Spain) revealed the presence of 2 new eimerian species, Eimeria gallaeciaensis sp. n. and E. emydis sp. n., as well as E. mitraria (Laveran and Mesnil, 1902) Doflein, 1909. Oocysts of E. gallaeciaensis n. sp. were found in 20 of 44 (45.4%) turtles and are subspherical to lightly ovoid-ellipsoid, 19.3 x 16.0 (17-22 x 15-18) microm, shape index 1.2 (1.1-1.3), with a smooth, single-layered wall. Micropyle and polar granule are absent, but an oocyst residuum is present. Sporocysts are ellipsoid, 9.7 x 5.1 (9-10 x 5-6) microm, shape index 1.9 (1.7-2.0), each with a sporocyst residuum and a conical Stieda body usually bearing 1-4 short and thin projections. Oocysts of E. emydis n. sp. were found in the feces of 5 of 44 (11.4%) turtles and are ovoid, rarely pear-shaped, 22.6 x 17.0 (20-25 x 15.5-18) microm, shape index 1.3 (1.2-1.5), with a smooth, single-layered wall with a slight thinning at the pointed end. Micropyle and polar granule are absent, and an oocyst residuum is present. Sporocysts are ellipsoid, 11.4 x 6.0 (9-13 x 5-7) microm, shape index 1.9 (1.6-2.2), each with sporocyst residuum and a prominent Stieda body bearing 3-5 club-shaped projections. In addition to the new species described, this is the first report of E. mitraria parasitizing E. orbicularis.     

Two new eimerians (Apicomplexa) from insectivorous mammals in Madagascar

Fecal samples from 126 insectivorous mammals in Madagascar were collected between spring 1999 and fall 2001. In the Afrosoricida, 21 species in 5 genera were sampled, including 17 species of Microgale (31/96, 32% infected), Hemicentetes semispinosus (1/2, 50%), Oryzorictes hova (1/5, 20%), Setifer setosus (8/13, 61.5%), and Tenrec ecaudatus (5/8, 62.5%); in the Soricomorpha, only Suncus murinus was examined and 1/2 (50%) were infected. Two morphotypes of eimeriid oocysts, representing 2 presumptive new species, were found in 47 (37%) infected animals; only 2 afrosoricid hosts (2% of all hosts, 4% of infected hosts) had both oocyst morphotypes. Sporulated oocysts of the first morphotype, Eimeria tenrececaudata n. sp., are subspheroidal, 18.8 × 17.4 (17-22 × 15-20), with a length∶width ratio (L/W) of 1.1 (1.0-1.2); they lack a micropyle but may contain 0-2 polar granules and a single, small round oocyst residuum, 3 × 2.3. Sporocysts are lemon-shaped, 9.9 × 6.6 (9-11 × 5-8), with a L/W of 1.5 (1.2-2.0); they have a prominent, slightly flattened Stieda body and a substieda body but lack a parastieda body. The sporocyst residuum consists of only a few granules between the sporozoites, which are sausage-shaped and have a large posterior refractile body. Oocysts of the second morphotype, Eimeria setifersetosa n. sp. are spheroidal to subspheroidal, 30.1 × 28.6 (27-34 × 25-34), with a L/W of 1.1 (1.0-1.2); they lack both micropyle and oocyst residuum, but 1-2 polar granules are usually present. Sporocysts are subspheroidal to broadly ellipsoidal, 9.6 × 7.3 (9-11 × 6-8), with a L/W of 1.3 (1.1-1.7); they have a broad Stieda body, lack sub- and parastieda bodies, and have a residuum of a few granules scattered throughout the sporocyst. Sporozoites were not clearly defined, but what seemed to be a single large refractile body is seen, presumably in each sporozoite.     

Description of Eimeria motelo sp. n. (Apicomplexa: Eimeriidae) from the yellow footed tortoise, Geochelone denticulata (Chelonia: Testudinidae), and replacement of Eimeria carinii Lainson, Costa & Shaw, 1990 by Eimeria lainsoni nom. nov

Eimeria motelo sp. n. is described from faeces of the yellow-footed tortoise, Geochelone denticulata (L.). Oocysts are irregularly ellipsoidal or cylindrical, with slightly expressed lobed protrusions and irregularities at the poles, possibly caused by wrinkling of the oocyst wall, 17 (15-19) x 9.4 (8.5-11) microm, shape index (length/width) being 1.81 (1.45-2). The oocyst wall is smooth, single-layered, 0.5 microm thick with no micropyle. There are no polar bodies. Sporocysts are ellipsoidal, 8.9 (7.5-10) x 4.4 (4-5) microm, shape index 2.03 (1.7-2.5). A sporocyst residuum is present, composed of many granules of irregular size. The sporozoites are elongate, lying lengthwise in the sporocysts. Comparison with other species of the genus Eimeria parasitising members of family Testudinidae indicates that the presently described coccidium represents a new species. The name of Eimeria carinii Lainson, Costa & Shaw, 1990 is found to be preoccupied by a homonym, Eimeria carinii Pinto 1928 given to a coccidium from Rattus norvegicus. Therefore, it is replaced by Eimeria lainsoni nom. nov.     

A pathogenic new species of Eimeria from the pygmy rabbit, Brachylagus idahoensis, in Washington and Oregon, with description of the sporulated oocyst and intestinal endogenous stages

In January 2003, fecal samples from 13 live pygmy rabbits, Brachylagus idahoensis (Merriam, 1891), were collected at the Oregon Zoo in Portland, Oregon, and sent to the University of New Mexico (UNM), Albuquerque, New Mexico, to be examined for coccidia. In July 2004, 14 more fecal samples were collected and sent to UNM, 6 from some of the same rabbits and 8 from 16 other rabbits (4 were pooled samples from siblings). In addition, tissue sections from 3 dead rabbits (2 from the Oregon Zoo, 1 from Washington State University) also were examined. Two of 4 (50%) pooled fecal samples and 8 of 17 (47%) 1-rabbit samples were positive for a single species of Eimeria, which we describe here as a new species. Sporulated oocysts were subspheroidal, 25.6 x 23.8 (22-28 x 21-27) microm, with a length:width (L:W) ratio of 1.1 (1.0-1.2). A micropyle (approximately 2 microm wide) and 0-1 polar granules were present, but an oocyst residuum was absent. Sporocysts were ellipsoidal, 13.4 x 8.1 (11-16.5 x 7.5-9) microm, with a L:W ratio of 1.7 (1.3-2.2), and they had a Stieda body and sporocyst residuum. Tissue sections showed a heavy infection of the villous epithelial cells of the proximal and mid-small intestine with coccidial endogenous stages, but no stages were found in liver hepatocytes. Meronts with approximately 46 (26-70) merozoites per infected cell appeared to be fully developed and were subspheroidal, 14.8 x 13.9 (13-18 x 10.5-16.5) microm. Developing macro- and microgamonts were indistinguishable from each other and were spheroidal to subspheroidal, 10.4 x 9.5 (9-11 x 7.5-10.5) microm. Mature macrogamonts were spheroidal to subspheroidal, 14.2 x 13.7 (12-17 x 11-16) microm, and mature microgamonts were smaller and subspheroidal, 11.9 x 10.8 (10.5-13 x 9-12) microm. This eimerian seems to be extremely pathogenic to young pygmy rabbits, and given the precarious nature of this unique genetic population, it appears to be an emerging pathogen that deserves immediate further study.     

Eimeria spp. (Apicomplexa: Eimeriidae) from the eastern chipmunk (Tamias striatus) in Pennsylvania with a description of one new species

Intestinal contents of 41 eastern chipmunks (Tamias striatus) from Armstrong County, Pennsylvania, were examined for the presence of Eimeria spp. Three previously named species were identified: E. lateralis (prevalence = 9%), E. ovata (3%), and E. vilasi (74%); 1 new species, Eimeria tamiensis n. sp. (74%), is described here. This report extends the geographic ranges of the named species into Pennsylvania. Sporulated oocysts of E. tamiensis n. sp. are ovoid and 18.6 x 14.5 (16-23 x 12-17) microm, with no micropyle or residuum. Sporocysts are ellipsoid and 8.6 x 5.4 (7-10 x 4-8) microm. with a Stieda body and granular residuum. Prevalences of E. lateralis and E. vilasi were similar to those reported previously. The differences in prevalences may be due to different life-history strategies of high- and low-prevalence Eimeria species.     

Two new species of coccidia (apicomplexa: Eimeriidae) from the bearded false chameleon Chamaeleolis barbatus (Sauria: polychridae) from cinco pesos, Pinar Del Río, Cuba.

Parasitological examination of bearded false chameleons Chamaeleolis barbatus freshly imported from Cuba revealed the presence of 2 species of coccidia that are described as new. Oocysts of Isospora chamaeleolidis n. sp. are spherical to slightly subspherical, 16.1 (13-21) x 15.6 (13-19) microm, with a brownish and bilayered wall approximately 1.0-1.5 microm thick; outer layer markedly pitted. 0.75-1.0 microm thick. One, rarely 2, globular polar granules, 1.5 in diameter are present in the sporulated oocysts. Sporocysts are ellipsoidal, 10.8 (10-13) x 7.8 (7-9) microm, with a smooth, colorless, and unilayered sporocyst wall. Stieda body and substieda bodies are present. A sporocyst residuum is present, consisting of small granules of irregular size scattered among the sporozoites. Oocysts of Eimeria chamaeleolidisbarbati n. sp. are broadly oval, 19.0 (17-21) x 15.7 (15-17) microm, with a bilayered, colorless oocyst wall approximately 0.75 thick; outer layer of oocyst wall is smooth, 0.5 microm thick. One or 2, rarely 4, globular, irregular polar granules, approximately 1.5 microm in diameter, are present in sporulated oocysts. Sporocysts are broadly oval, 7.4 (7-8.5) x 6.1 (5.5-7) microm, with a smooth, colorless, and unilayered sporocyst wall, composed of 2 valves joined by suture; Stieda body and substieda bodies are absent.     

A new species of Eimeria (Apicomplexa, Eimeriidae) from the weedy sea dragon Phyllopteryx taeniolatus (Osteichthyes: Syngnathidae)

A new species of intestinal coccidian is described from the weedy or common sea dragon Phyllopteryx taeniolatus housed at the New England Aquarium in Boston and at the Shedd Aquarium in Chicago, USA. Live oocysts of Eimeria phyllopterycis sp. n. are spherical, 30.9 (28.0-34.4) microm, with a thin, single-layered wall. Both a micropyle and oocyst residuum are absent and a large polar granule is sometimes present. Sporocysts are ellipsoidal and elongate, 24.3 x 10.4 (23.4-25.6 x 9.2-11.2) microm, with Stieda and substieda bodies; shape index (length/width) 2.33 (2.14-2.70). A sporocyst residuum is present, consisting of numerous granules of various sizes. Sporozoites each possess 3 refractile bodies. Preliminary evidence suggests that the coccidian may affect the health of sea dragons; however, it could not be determined whether this parasite caused significant morbidity or mortality.     

A new Eimeria (Apicomplexa: Eimeriidae), possessing mitra-shaped oocysts, from the Neotropical chelid turtle Batrachemys heliostemma (Testudines: Chelidae), and its comparison with Eimeria mitraria (Laveran & Mesnil 1902)

Eimeria jirkamoraveci sp. n. is described from faeces of two specimens of the toad-headed, side-necked turtle Batrachemys heliostemma collected at Iquitos in Peru. Oocysts are ovoid to almost spherical, 10.6 (8-12) x 8.9 (7-10) microm, without micropyle, polar granule and oocyst residuum. One conically stretched end and three blunt conical tubercles at the opposite end of oocyst give it mitra-like appearance. Sporocysts are elongated, ellipsoidal, 7.2 (6-8) x 4.1 (4-4.5) microm, with a small, knob-like Stieda body and sporocyst residuum composed of fine granules. To avoid possible conspecificity, the described new species is thoroughly compared with the most similar coccidium, E. mitraria, collected from its type host, Chinemys reevesii.     

Coccidia of Brazilian mammals: Eimeria corticulata n. sp. (Apicomplexa: Eimeriidae) from the anteater Tamandua tetradactyla (Xenarthra: Myrmecophagidae) and Eimeria zygodontomyis n. sp. from the cane mouse Zygodontomys lasiurus (Rodentia: Cricetidae)

Feces from a specimen of Tamandua tetradactyla (Linn.) from Portel, Pará State, north Brazil, contained two different coccidial oocysts; one identified as Eimeria tamanduae Lainson 1968, and the other as a new species, described here as Eimeria corticulata n. sp. Oocysts of E. corticulata are ellipsoidal, 37.4 x 30.4 (31.2-43.7 x 23.7-35.0) microns, shape index (length/width) 1.2 (1.0-1.5). Oocyst wall 2.5-3.7 microns thick and composed of two layers; an outer thick, brown-yellow one with radial striations, and a thin inner smooth one: no visible micropyle. Oocyst residuum a large globule of about 10.7 x 10.3 microns, usually accompanied by a number of smaller attached globules. Sporocysts ellipsoidal, 21.0 x 11.0 (20.0-22.5 x 10.0-12.5) microns, with a conspicuous Stieda body; shape index 1.9 (1.6-2.2). Sporocyst residuum a small number of scattered granules: sporozoites 18.7 x 5.0 microns, with a large posterior refractile body. Eimeria zygodontomyis n. sp. is described in feces from Zygodontomys lasiurus (Lund) from the Serra dos Carajás, Pará. Oocysts ellipsoidal to cylindrical, 16.5 x 12.0 (13.7-18.7 x 11.2-12.3) microns, shape index 1.4 (1.2-1.5). Wall colorless, smooth, single-layered and about 0.6 micron thick: no micropyle. No oocyst residuum, but a polar granule of about 1.8 x 1.0 microns is sometimes present. Sporocysts ellipsoidal, 8.4 x 5.5 (7.5-8.7 x 5.0-6.2) microns, shape index 1.5 (1.4-1.7), with a thin colorless wall and a delicate Stieda body. Sporozoites enclose a compact residuum of about 2.5 x 3.7 microns.