Pseudacris Fitzinger 1843

Duszynski, Donald W., Bolek, Matthew G. & Upton, Steve J., 2007, Coccidia (Apicomplexa: Eimeriidae) of amphibians of the world, Zootaxa 1667 (1667), pp. 1-77 : 29-32

Host genus Pseudacris Fitzinger 1843

(16 spp.)

Eimeria flexuosa Upton and McAllister 1988 ( Figs. 12, 54) Type host: Pseudacris streckeri Wright and Wright 1933 , Strecker's chorus frog.

Other hosts: None reported to date.

Type locality: NORTH AMERICA: U.S.A. Texas, Dallas County .

Geographic distribution: NORTH AMERICA: U.S.A. Texas.

Description of sporulated oocyst: Oocyst shape: irregular; number of walls: 1; wall thickness: ~0.5; wall characteristics: flexible and encloses sporocysts tightly; L: 17.0 (15–19); M and OR: absent; PG: present; 1 (rarely more), 1.6–2.5 wide. Distinctive features of oocyst: Single-layered, flexible wall that tightly encloses the sporocysts.

Description of sporocyst and sporozoites: Sporocyst shape: ovoidal; L x W: 10.3 x 7.3 (10–12 x 6–8); L/W ratio: 1.4 (1.3–1.6); SB: present as slight thickening at pointed end; SSB and PSB: absent; SR: present; SR characteristics: 6.6 x 5.1 (5–8 x 4–6) composed of numerous coarse granules, each up to 2.5 wide, but sometimes diffuse with scattered granules; SZ: 9.4 x 2.4 (8–10 x 2–3) in situ, each with 2 RB; anterio-central RB usually spheroidal, 2.0 (1–3), while posterior RB is spheroidal, 1.7 (1–2); indistinct N located between the RBs. Distinctive features of sporocyst: large SR made up of large, coarse granules.

Prevalence: 10 of 34 (29%).

Sporulation: Presumably endogenous.

Prepatent and patent periods: Unknown.

Site of infection: Unknown (see Remarks).

Endogenous stages: Unknown.

Pathology: Unknown.

Materials deposited: None.

Remarks: Only 2 other eimerians from anurans are described with oocyst walls thin enough to adhere to the sporocysts and that produce irregularly-shaped oocysts: G. neglecta and E. ranae . This species is distinguished from the former ( Fig. 27) by its larger oocysts (17 vs. 9–10) and sporocysts (10 x 7 vs. 3.5–4). Although the oocysts and sporocysts of E. ranae are similar in size to those of E. flexuosa , the latter ( Fig. 12) lacks an OR which is present in E. ranae . Upton and McAllister (1988) reported the site of infection for E. flexuosa as the intestine, but their oocysts were recovered from the feces and no attempt was made to check what organs were infected with developmental stages of this species; therefore, the site of infection is unknown.

Eimeria streckeri Upton and McAllister 1988 ( Figs. 13, 14, 55, 56)

Type host: Pseudacris streckeri Wright and Wright 1933 , Strecker's chorus frog.

Other hosts: Pseudacris triseriata (Wied-Nuweid 1838) , Western chorus frog.

Type locality: NORTH AMERICA: USA, Texas, Dallas County .

Other localities: NORTH AMERICA: USA, Nebraska, Lancaster County, Pawnee Lake (40° 51’ 10.8” N, 96° 53’ 6.6” W) .

Geographic distribution: NORTH AMERICA: USA, Texas, Nebraska .

Description of sporulated oocyst: Oocyst shape: spheroidal, rarely subspheroidal; number of walls: 1; wall thickness: ~0.7; wall characteristics: smooth; L x W: 18.8 x 18.7 (17–21.5 x 17–21); L/W ratio: 1.0 (1.0– 1.1); M: absent; OR: spheroidal, 8.0 (6–11), composed of numerous coarse granules surrounding a large vacuolated or globular area; PG: absent (usually), although 1 may be found rarely. Distinctive features of oocyst: none.

Description of sporocyst and sporozoites: Sporocyst shape: ovoidal; L x W: 11.1 x 7.7 (10–13 x 7–9); L/W ratio: 1.5 (1.2–1.7); SB: present as slight thickening at pointed end, indistinct; SSB and PSB: absent; SR: present; SR characteristics: an aggregate of granules bound by a limiting membrane, 6.6 x 5.7 (5–8 x 4–7), but additional granules are often found free among the SZ; SZ: 11.0 x 2.6 (10–13 x 2–3) in situ, each with 2 RB; anterior-central RB spheroidal to slightly ovoidal, 2.2 x 2.0 (1–3 x 1–2); posterior RB spheroidal, 1.6 (1–2); N located between the 2 RBs. Distinctive freatures of sporocyst: none.

Prevalence: 16 of 34 (47%) in P. streckeri in Texas ( Upton & McAllister 1988); 2 of 30 (7%) in P. t. triseriata in Nebraska ( Bolek et al. 2003)

Sporulation: Presumably endogenous.

Prepatent and patent periods: Unknown.

Site of infection: Unknown (see Remarks).

Endogenous stages: Unknown.

Pathology: Unknown.

Materials deposited: Photosyntypes of sporulated oocysts in the HWML, Lincoln, NE (HWML 16977).

Remarks: About half of the known eimerians from anura have spheroidal to subspheroidal sporulated oocysts. Of these, only 5 are reported to possess an OR: E. algonquini , E. cyanophlyctis , E. leptodactyli , E. prevoti and E. streckeri . Sporulated oocysts of this species differ from E. algonquini ( Fig. 22) by having larger oocysts and much smaller sporocysts that have a SB, which those of E. algonquini lack. This species’ oocysts and sporocysts are distinguished from those of E. cyanophlyctis ( Fig. 8) by being more spheroidal and the presence of a SR, which E. cyanophlyctis lacks. They differ from E. leptodactyli ( Fig. 20) by having smaller and more spheroidal oocysts and larger sporocysts, and from E. prevoti ( Fig. 25) by its more spheroidal shape and much larger OR. The oocysts seen by Bolek et al. (2003) in P. t. triseriata from Nebraska were remarkably similar to those in the original description ( Upton & McAllister 1988) in size and shape. The major difference was that those from Nebraska had a distinctive globular body in the OR, which remained constant in form during a period of 6 mo while being refrigerated in 2.5% K 2 Cr 2 O 7 solution. Upton and McAllister (1988) reported the site of infection for this species as the intestine, but their oocysts were recovered from the feces and no attempt was made to check what organs were infected with the developmental stages of E. streckeri ; therefore, the site of infection of this species is unknown.

Isospora cogginsi Bolek, Janovy and Irizarry-Rovira 2003 ( Figs. 15, 57)

Type host: Pseudacris triseriata (Wied-Nuweid 1838) , Western chorus frog.

Other hosts: None to date.

Type locality: NORTH AMERICA: USA, Nebraska, Lancaster County, Pawnee Lake (40° 51’ 10.8” N, 96° 53’ 6.6” W) .

Geographic distribution: NORTH AMERICA: USA, Nebraska.

Description of sporulated oocyst: Oocyst shape: ovoidal, rarely subspheroidal; number of walls: 1; wall thickness: ~0.5; wall characteristics: smooth, colorless; L x W: 19.3 x 15.1 (18–23 x 11–20); L/W ratio: 1.3 (1.1–1.6); M, OR, PG: all absent. Distinctive features of oocyst: wall frequently ruptures after sporulation, releasing free sporocysts.

Description of sporocyst and sporozoites: Sporocyst shape: ovoidal with a thin, colorless wall, ~0.4; L x W: 13.3 x 9.9 (11–15 x 9–13); L/W ratio: 1.3 (1.0–1.6); SB, SSB, PSB: all absent; SR: present; SR characteristics: spheroidal, 5.5 x 5.3 (4–7 x 4–7) with numerous coarse granules bound by a membrane; SZ: elongate, 12.8 x 3.2 (10–15 x 2.5–4), arranged so that 2 SZ lie in one direction and the other 2 lie in the opposite direction; each with 2 RBs; anterior-central RB spheroidal to ovoidal, 2.3 x 2.4 (2–3 x 2–3); posterior RB spheroidal to ovoidal, 2.6 x 2.4 (2–3 x 2–3); N, indistinct, located between RBs. Distinctive features of sporocyst: SR bound by a distinct membrane.

Prevalence: 23 of 30 (70%) of adult frogs; 4 of 16 (25%) of tadpoles.

Sporulation: Exogenous; oocysts passed unsporulated or semi-sporulated in the sporoblast stage and become fully sporulated in 12–24 h at room temperature.

Prepatent and patent periods: Unknown.

Site of infection: Supra-nuclear in luminal epithelial cells of the posterior small intestine, although in heavily infected frogs, endogenous stages are found throughout the small intestine.

Endogenous stages: Mature meronts were 14.8 x 8.8 (12–19 x 7–10) and contained 8–9 banana-shaped merozoites, 6.1 x 1.4 (5–7 x 1–2). Developing microgamonts with peripherally located N were 11.6 x 9.3 (10– 16 x 7–12), mature microgamonts with numerous microgametes were 18.2 x 14.8 (16–22 x 13–17), and mature macrogamonts with numerous granules and vacuoles were 11.9 x 10.3 (10–14 x 8–13). Freshly released oocysts with basophilic sporoplasm and numerous granules were 14.1 x 11.7 (12–15 x 10–13); these began sporulating in the gut lumen.

Pathology: Unknown.

Materials deposited: Sporulated oocysts preserved in 70% ethanol in the HWML (HWML 16978) as are photosyntypes of sporulated oocysts (HWML 16979), histological sections of adult frog small intestine (HWML 16980) and histological section of tadpole small intestine (HWML 16981); the symbiotype host is in the University of Nebraska State Museum (ZM-23844).

Remarks: Of the 22 isosporans reported from anuran hosts, this species most closely resembles I. cruzi Pinto and Vallim, 1926 , from Scinax spp. (Hylidae) from South America ( Pinto & Vallim 1926; Carini 1936; Walton 1947). Sporulated oocysts of this species differ from those of I. cruzi ( Fig. 17) in being a little smaller (19.3 x 15.1 vs. 20.7 x 17.2) and more ovoidal in shape (1.3 vs. 1.2). Additionally, the SR is bound by a distinct membrane not mentioned in I. cruzi . Based on these subtle differences as well as differences in hosts and geographic location, Bolek et al. (2003) were justified in naming this species from Pseudacris as distinct.

Isospora delicatus Upton and McAllister 1988 ( Figs. 16, 58)

Type host: Pseudacris strecker Wright and Wright 1933 , Strecker's chorus frog.

Other hosts: Pseudacris illinoensis Smith 1951 , Illinois chorus frog.

Type locality: NORTH AMERICA: USA, Texas, Dallas County .

Geographic distribution: NORTH AMERICA: USA, Arkansas, Texas .

Description of sporulated oocyst: Oocyst shape: spheroidal, rarely subspheroidal; number of walls: 1; wall thickness: ~0.6; wall characteristics: smooth; L x W: 15.8 x 15.7 (13–17 x 13–17); L/W ratio: 1.0 (1.0– 1.1); M, OR, PG: all absent. Distinctive features of oocyst: none.

Description of sporocyst and sporozoites: Sporocyst shape: spindle-shaped and pointed at both ends; L x W: 13.5 x 8.0 (11–15 x 7–10); L/W ratio: 1.7 (1.5–1.8); SB: present as a large thickening at 1 pointed end; SSB: absent; PSB: not described, although the end opposite of the SB tapers markedly; SR: present; SR characteristics: numerous coarse granules scattered among the SZ; SZ: elongate, 11.9 x 2.4 (10–14 x 2–3) in situ, each with 2 RBs; anterior RB spheroidal, 1.8 (1–2); posterior RB slightly larger, also spheroidal, 2.0 (1–3); N, indistinct, located between the 2 RBs. Distinctive features of sporocyst: distinct spindle-shape, pointed at both ends, resembling the oocysts of Monocystis species from earthworms.

Prevalence: 5 of 34 (15%) in type host; 1 of 8 (12.5%) in adult P. illinoensis .

Sporulation: Presumably endogenous.

Prepatent and patent periods: Unknown.

Site of infection: Unknown (see Remarks).

Endogenous stages: Unknown.

Pathology: Unknown.

Materials deposited: None.

Remarks: Only I. wenyoni ( Fig. 6) has oocysts that are similar in size to those of this species. They differ, however, in that those of I. delicatus are more spheroidal and have larger sporocysts. Also, no other species of Isospora from an anuran has such spindle-shaped sporocysts. Although Upton and McAllister (1988) reported the site of infection for this species as the intestine, the oocysts were recovered from the feces and no attempt was made to check what organs were infected with I. delicatus ; therefore, the site of infection of this species is unknown.