Integrative taxonomy confirms that Gregarina garnhami and G. acridiorum (Apicomplexa, Gregarinidae), parasites of Schistocerca gregaria and Locusta migratoria (Insecta, Orthoptera), are distinct species

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Table 1

Morphological differences between five very similar gregarines of acridians reported in the literature. This table is based on individual descriptions provided by the authors of [7, 21, 22, 24, 30]; see also [17]. D, diameter; L, length; W, width; TL, total length.

Gregarine	Gregarina acridiorum (Léger, 1893) Labbé, 1899 [24] [21]	Gregarina garnhami Canning, 1956 [7]	Gregarina rigida (Hall, 1907) Ellis, 1913 [17]	Gregarina ronderosi, Lange & Wittenstein, 2002 [22]	Gregarina caledia, Ninham, 1995 [30]
Hosts	Caelifera: Acrididae, Tetrigidae; Ensifera: Tettigoniidae	Caelifera: Acrididae	Caelifera: Acrididae; Ensifera: Tettigoniidae	Caelifera: Acrididae	Caelifera: Acrididae
Infected sites in hosts	Midgut	Early stages in gastric ceca and occasionally in the midgut; gamonts in the midgut	Early stages in gastric ceca, near the anterior end of the midgut	Trophozoites, solitary or associated gamonts in gastric ceca and gut; gametocysts in the hindgut	Trophozoites, solitary or associated gamonts in gastric ceca and midgut; gametocysts in the hindgut
Trophozoites – gamonts
Gamonts	Gamonts: cylindrical, ovoid in older forms, endocyte yellow orange. L: ~ 400 μm, W: 160 μm	Gamonts: rather stout bodied in older forms, endocytes are pale yellow. L: 250–554 μm	Gamonts: rather stout bodied, endocytes are brownish orange. L: 250–750 μm W: 130–210 μm	Trophozoite (epimerite): L: 10.4–275 μm, more slender than gamonts; Gamonts: rather stout bodied, endocytes are pale yellow. L: 80–348 μm	Gamonts: pale-yellow, ovoid then cylindrical L: 180–264 μm W: 60–70 μm Mean: 222 μm × 65 μm
Association Length	TL: up to 1000 μm	TL: 500–1110 μm	TL: up to 1425 μm (average: 550 μm). Protomerite smaller in the satellite than in the primite	TL: 160–700 μm (average: 425 μm). Primites and satellites are similar in size and shape	TL: 515 μm. Primites and satellites are similar in size. Also seen: primite with 2 small satellites
Epimerite	Small, spherical with a short stalk.	Small, globular with a short stalk.	Small spherical hyaline knob.	Conical when attached, globular and smaller in free trophozoites	Globular
Protomerite	Sub-globular in primites, depressed at the anterior end in satellites.	Conical in young stages, subspherical in older stages, widest at the septum, tapering towards the anterior end, flattened in satellite.	Somewhat flattened, 3 times wider than long, generally less constriction at septum more or less indistinct.	Sub-globular in primites, depressed at anterior end in satellites, less flattened than in G. garnhami	Rounded anterior end
Deutomerite	Cylindrical, rounded posterior end	Cylindrical or rounded, with sharply pointed posterior end	Cylindrical or barrel-shaped, little wider than protomerite, broadly rounded end or flattened “cornered” extremity	Cylindrical, rounded posterior end, wider than protomerite, barrel-shaped in older forms	Cylindrical, in small gamonts, wider than in protomorites and rounded in older forms
Gametocysts – oocysts
Gametocysts	D: 500 μm, thick ectocyst	D: 114–470 μm (exclusive of the ectocyst)	D: 300 μm in average. Yellow orange color. Thick ectocyst	D: 96–376 μm. Thick ectocyst	D: 228–312 μm (mean 270 μm). Yellow orange color. Ectocyst (24–100 μm thick)
Basal discs	Yellow orange	Yellow orange	Not mentioned	Orange	Orange
Sporoducts	12–15, with a swollen basal part, L > 1/2 cyst diameter	8, L: 1/3 cyst diameter (without ectocyst)	10 or more, short	12–15, L: up to 60 μm	5 to more than 10
Oocysts (sporocysts)	Dolioform^*, double wall	Dolioform^*, thick wall	Barrel-shaped^*	Dolioform^* or Barrel-shaped^*	Barrel-shaped^*
Oocysts (sporocysts)	7.6 μm × 3.3 μm	6.5–7 μm × 4 μm	8 μm × 5 μm	5 μm × 3.2 μm	12 μm × 6 μm

Depending on the authors, the terms “dolioform” and/or “barrel-shaped” were used to describe the shape of oocysts. Note also that oocysts were called sporocysts in all these historical descriptions.

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