The genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), an avian coccidia, is characterized by monosporocystic and octasporozoic oocysts without Stieda and substieda bodies. Some members of Eumonospora, which infect several raptor species, exhibit high levels of pathogenicity, making eumonosporiosis the leading cause of death in captive-bred raptors. The host specificity of these species appears to be mesostenoxenous, as evidenced by unsuccessful transmission between different orders of avian hosts. However, several studies have detected Eumonospora spp. in taxonomically distant avian hosts, indicating that some of these species may be euryxenous. In the current study, diarrheic fecal examination of a captive-bred juvenile merlin (Falconiformes: Aves) in Tokyo, Japan, was conducted, and a large number of oocysts were morphologically and molecularly identified as E. henryae (Yakimoff and Matschulsky, 1932), a coccidia species reported only in Strigiformes. This is a new recorded host for this coccidia. Phylogenetic analyses via Bayesian inference and maximum likelihood methods using concatenated genomic datasets consisting of nuclear 18S rDNA, nuclear 28S rDNA and mitochondrial cytochrome C oxidase subunit 1 gene, revealed a well-supported monophyletic clade of Eumonospora spp. belonging to the family Sarcocystidae Poche 1913, which largely corresponded to the avian host phylogram. Therefore, based on distinguishable oocyst morphology, a new subfamily, Eumonosporinae, within the family Sarcocystidae, is proposed, and a reconsideration of the definition of Sarcocystidae is suggested. Further molecular characterization of this emerging pathogen, as well as clarification of its complete life cycle, including cyst-forming ability, is required for more appropriate generic assessment.

Eumonospora Allen属，1933年（Apicomplexa：Sarcocystidae），是一种禽球菌，其特征是单孢囊性和八孢子性卵囊，没有斯蒂达氏体和下基质。Eumonospora的某些成员感染了几种猛禽，其致病性很高，使eumonosporiosis成为圈养猛禽死亡的主要原因。这些物种的寄主特异性似乎是中毒的，这由不同顺序的禽寄主之间的不成功传播证明。但是，一些研究发现了Eumonosporaspp。在分类学上较远的禽类寄主中，表明这些物种中的某些可能是雌性的。在当前的研究中，对日本东京的圈养幼年梅林（Falconiformes：Aves）进行了腹泻性粪便检查，并从形态和分子学上将大量卵囊鉴定为亨氏大肠杆菌（Yakimoff and Matschulsky，1932）。 ，仅在剑形目中报告的球菌种。这是此球菌的新记录宿主。通过使用包括核18S rDNA，核28S rDNA和线粒体细胞色素C氧化酶亚基1基因的级联基因组数据的贝叶斯推论和最大似然方法进行的系统发育分析，揭示了Eumonospora单系进化枝spp。属于Sarcocystidae Poche家族，1913年，在很大程度上对应于禽类宿主系统志。因此，基于可区分的卵囊形态，提出了一个新的亚科，属于孢囊虫科，属于单孢菌科，并建议重新考虑囊虫科的定义。为了更适当的通用评估，需要对该新兴病原体进行进一步的分子表征，并阐明其完整的生命周期，包括形成囊肿的能力。