Blood flukes of Asiatic softshell turtles: revision of Coeuritrema Mehra, 1933 (Digenea: Schistosomatoidea) and a new species infecting Chinese softshell turtles, Pelodiscus sinensis (Trionychidae), from Vietnam

Abstract

Coeuritrema Mehra, 1933, previously regarded as a junior subjective synonym of Hapalorhynchus Stunkard, 1922, herein is revised to include Coeuritrema lyssimus Mehra, 1933 (type species), Coeuritrema rugatus (Brooks et Sullivan, 1981) comb. n., and Coeuritrema platti Roberts et Bullard sp. n. These genera are morphologically similar by having a ventral sucker, non-fused caeca, two testes, a pre-testicular cirrus sac, an intertesticular ovary, and a common genital pore that opens dorsally and in the sinistral half of the body. Phylogenetic analysis of the D1-D3 domains of the nuclear large subunit ribosomal DNA (28S) suggested that Coeuritrema and Hapalorhynchus share a recent common ancestor. Coeuritrema is morphologically most easily differentiated from Hapalorhynchus by having ventrolateral tegumental papillae and a definitive metraterm that is approximately 3−7× longer than the uterus. Coeuritrema comprises species that reportedly infect Asiatic softshell turtles (Testudines: Trionychidae) only, whereas Hapalorhynchus (as currently defined) comprises blood flukes that reportedly infect those hosts plus North American musk turtles (Sternotherus Bell in Gray) and mud turtles (Kinosternon Spix), both Kinosternidae, North American snapping turtles (Chelydridae), Asiatic hard-shelled turtles (Geoemydidae) and African pleurodirans (Pelomedusidae). Coeuritrema platti sp. n. infects the blood of Chinese softshell turtles, Pelodiscus sinensis (Wiegmann), cultured in the Da Rang River Basin (Phu Yen Province, Vietnam). It differs from C. lyssimus by having a narrow hindbody (< 1.6× forebody width), ventrolateral tegumental papillae restricted to the hindbody, a short cirrus sac (< 10% of corresponding body length), a transverse ovary buttressing the caeca, a short, wholly pre-ovarian metraterm (~ 10% of corresponding body length), and a submarginal genital pore. It differs from C. rugatus by having small ventrolateral tegumental papillae, testes without deep lobes, and a Laurer's canal pore that opens posterior to the vitelline reservoir and dorsal to the oviducal seminal receptacle. The new species is only the second turtle blood fluke reported from Vietnam.

Neotropical Turtle Blood Flukes: Two New Genera and Species from the Amazon River Basin with a Key to Genera and Comments on a Marine-Derived Parasite Lineage in South America

“…During July 2016, the viscera of 5 matamatas (C. fimbriata) from the Bele´n Market (3845 0 32.08 00 S, 73814 0 53.15 00 W), Iquitos, Peru (Amazon River), were examined opportunistically for blood fluke infections following previously published procedures (Roberts et al, 2016a(Roberts et al, , 2016b(Roberts et al, , 2016c(Roberts et al, , 2018a(Roberts et al, , 2018b(Roberts et al, , 2019 observed microscopically prior to fixation, fixed in 5À10% neutral buffered formalin (nbf) for morphology, or preserved in 95% non-denatured ethanol (EtOH) for DNA extraction. The ovoid TBF specimens with a relatively thick tegument (i.e., specimens of the first new species described below) were routinely heat-killed on glass slides using a butane hand lighter under little or no coverslip pressure.…”

“…1557310-1557319). Classification and anatomical terms for TBFs follow Roberts et al (2016aRoberts et al ( , 2016bRoberts et al ( , 2016c. Turtle scientific and common names follow van Dijk et al (2014), and higher classification of turtles follows Pereira et al (2017).…”

A new species of Spirorchis MacCallum, 1918 (Digenea: Schistosomatoidea) and Spirorchis cf. scripta from chicken turtle, Deirochelys reticularia (Emydidae), with an emendation and molecular phylogeny of Spirorchis

“…scripta (KY091666), the new species (KY091664) and Spirorchis picta (KY091665) plus six other TBFs in GenBank (Table 1). Methods for sequence alignment and phylogenetic tree construction follow Roberts et al (2016b).…”

“…scripta (KY091666), the new species (KY091664) and Spirorchis picta (KY091665) plus six other TBFs in GenBank (Table 1). Methods for sequence alignment and phylogenetic tree construction follow Roberts et al (2016b).The holotype and paratypes of the new species and vouchers of the redescribed species were deposited in the United States National Museum (USNM, Washington, D.C.) and the Institute of Parasitology (IPCAS, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic). MacCallum, 1918, emended Figs.…”

“…Later, Stunkard (1923), Byrd (1939) and Ulmer (1959) histologically differentiated the proximal portion of the uterus from the metraterm in species of Spirorchis. These structures probably do comprise a functional 'egg chamber' (Roberts et al 2016b) as in S. elegans and S. scripta. However, S. picta and the new species described herein have a uterus comprised wholly of a metraterm immediately distal to the ootype.…”