Eimeriid coccidia (Apicomplexa: Eimeriidae) from geoemydid turtles (Testudines: Geoemydidae) with a description of six new species

The genus Eimeria Schneider, 1875, comprises of ＞ 1,000 described species, making it the most species-rich among coccidians. Within chelonian hosts, only 61 Eimeria spp. have been described to date, with the majority known from the New World. Yet, the Southeast Asia region has the highest turtle diversity in the world, from which only a few species have been discovered. Furthermore, the largest turtle family, Geoemydidae Theobald, 1868, has received little attention. In the past decade we examined samples from wild-caught geoemydid turtles from Southeast Asia and adjacent areas. Our work revealed considerable diversity of turtles' coccidia and we describe six new species of Eimeria in this report. Eimeria surinensis sp. n. from Malayemys subtrijuga caught in Thailand possesses almost spherical oocysts (22.6×21.4), with spindle-shaped to ellipsoidal sporocysts pointed at both poles (13.4×6.9). Eimeria pangshurae sp. n. from Pangshura sylhetensis residing in India has ellipsoidal to spherical oocysts (16.5×13.2) and broadly-ellipsoidal to flask-shaped sporocysts (11.1×5.7), with a Stieda body frequently connected with two to four filaments. Eimeria hynekprokopi sp. n. from Vietnamese Cuora galbinifrons has extremely thin-walled and fragile, elongated oocysts, and is a bit pointed at one pole (15.6×8.7), carrying ellipsoidal to broadly oval sporocysts (6.5×4.3). Eimeria zbatagura sp. n. from Batagur baska sampled in Singapore has tiny sub-spherical to broadly ellipsoidal oocysts (7.4×6.3 μm) with almost oval but relatively small sporocysts (5.5×3 μm). The broadly ellipsoidal, fragile oocysts of Eimeria petrasi sp. n. (22.9×18.6 μm) collected from Cyclemys dentata in the Philippines possess a wavy outer surface of the oocyst wall, and oval to ellipsoidal sporocysts (12.3×6.5 μm). Eimeria palawanensis sp. n. from Cyclemys dentata found in the Philippines has thin-walled and fragile spherical oocysts (14-17 μm wide), plus elongated, ellipsoidal sporocysts (12.6×5.8 μm). We also recorded Eimeria arakanensis Siroký et Modrý, 2006 from the new host species-Cuora flavomarginata collected in China. Since many chelonians are critically endangered species, their parasite biodiversity will be lost following the collapse of their populations.