Eimeria vicoensis, Bezerra-Santos & Ramos & Duszynski & Araújo & Campos, 2020

Bezerra-Santos, Marcos Antônio, Ramos, Bárbara Cristina Félix Nogueira Rafael Antonio Nascimento, Duszynski, Donald W., Araújo, Jackson Victor De & Campos, Artur Kanadani, 2020, Eimeria spp. (Apicomplexa: Eimeriidae) in Didelphis aurita Wied-Neuwied, 1826 (Didelphimorphia: Didelphidae) and description of a new species infecting this opossum, Zootaxa 4878 (3), pp. 572-580 : 576-577

Eimeria vicoensis n. sp.

( Figs. 5A, B, C )

Type host: Didelphis aurita (Wied-Neuwied 1826) ( Didelphimorphia : Didelphidae ), Black-eared Opossum.

Type locality: South America: Brazil: Atlantic Forest, municipality of Viçosa , Minas Gerais (20°45´14” S and 42°52´54” W) .

Other hosts: Unknown, none to date.

Description of sporulated oocyst: Oocyst shape: Spheroidal to subspheroidal; number of walls: 2; wall characteristics: smooth, colorless, ~1.0 thick; L x W (n = 58): 21.7 × 20.7 (20-23 × 19-23), L/W ratio: 1.05; large polar granule present, highly refractile, ~2.7 x 1.6; micropyle and oocyst residuum, both absent.

Description of sporocyst and sporozoites: Sporocyst shape: ovoidal; L x W (n = 58): 10.6 × 8.0 (9-12 × 7-9); L/W ratio: 1.3; Stieda body present as a small structure at one end of sporocyst ( Fig. 5A , black arrow); substieda and parastieda bodies both absent; sporocyst residuum present as a compact mass of granules; refractile bodies in sporozoites were not seen.

Prevalence: Oocysts of this morphotype were found in 13/43 (30.2%) D. aurita and they always were accompanied by oocysts of one to four other Eimeria species.

Sporulation: Exogenous. Oocysts were completely sporulated after a period of 7 days in 2.5% potassium dichromate solution (K 2 Cr 2 O 7).

Prepatent and patent periods: Unknown.

Site of infection: Unknown, oocysts were recovered from feces after the animals defecated.

Pathogeny: Unknown.

Materials deposited: Photosyntypes ( Frey et al. 1992) are deposited in the Parasitology Collection of the Laboratório de Biologia de Coccídios at the Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil, repository number is P-98/2019 (available at http://r1.ufrrj.br/labicoc/colecao.html) .

Etymology: The specific epithet is derived from the name of the municipality where the study was performed.

Remarks: Our new species was described in 13/43 (30%) animals examined and its sporulated oocysts present sufficient distinctive characteristics that allowed us to distinguish it as new to science. The sporulated oocysts of E. vicoensis n. sp. differs from other described Eimeria spp. of marsupials in several structural and morphometric pa-rameters. Most Eimeria spp. previously described infecting didelphid marsupials have a striated outer oocyst wall, except for E. didelphydis , in which this structure is smooth, as it is in our new form, E. vicoensis n. sp. However, there are four consistent parameters that allow us to distinguish sporulated oocysts of these two forms. First, sporulated oocysts of E. vicoensis always have a highly refractile polar granule, while those of E. didelphydis always lack one. Second, oocyst size is a consistent distinguishing feature. The sporulated oocysts of E. didelphydis are smaller than those of E. vicoensis , L × W: 16 × 16, L/W ratio: 1.0 (spheroidal) vs 21.7 × 20.7, L/W ratio: 1.05 (subspheroidal). Two other distinguishing differences between oocysts of the two forms are in their sporocysts. Those of E. didelphydis are distinctly smaller than those of E. vicoensis , L × W: 10 × 6, L/W ratio: 1.7 vs 11 × 8, L/W ratio: 1.3, and the SR of the former consists of only a few scattered granules, while the SR of E. vicoensis is composed of a compact mass of large granules.

Figures

FIGURE. 5 Sporulated oocyst of Eimeria vicoensis n. sp. isolated from the opossum Dildelphis aurita in Brazil. A—Stieda body (black arrow) and compact sporocyst residuum in the center of the lower sporocyst (green arrow); B—highly refractile polar granule (black arrow) and smooth oocyst wall; C—Line drawing of E. vicoensis n. sp. (Scale bar 10µm).