A New Species of Sprirorchis MacCallum, 1918, (Digenea: Schistosomatoidea) and Spirorchis scripta Stunkard, 1923, Infecting River Cooter, Pseudemys concinna (Le Conte, 1830), (Testudines: Emydidae) in the Pascagoula River, Mississippi, U.S.A., Including an Updated Phylogeny for Spirorchis spp.

Document Type

Article

Publication Date

7-1-2018

Department

Coastal Sciences, Gulf Coast Research Laboratory

Abstract

River cooters (Pseudemys concinna [Le Conte, 1830]) from the Pascagoula River (30°37′07.67″N; 88°36′44.53″W; Mississippi, U.S.A.) were infected by Spirorchis scripta Stunkard, 1923, and Spirorchis testiplexus n. sp. The new species resembles Spirorchis artericola (Ward, 1921) Stunkard, 1921, and Spirorchis innominatus Ward, 1921 (type species), by having a median esophageal diverticulum, ceca that extend slightly posterior to the genitalia, 10 testes, and a testicular column that extends anteriad to near the cecal bifurcation. Based on a comparative morphological study of existing type materials, vouchers, and published descriptions of similar congeners, S. testiplexus is unique by the combination of having a proportionally wider body, laterally directed cecal diverticula, deeply lobed testes, a testicular column that fills the intercecal space, and an external seminal vesicle that occupies the space between the posterior-most testis and the ovary and that passes dorsal or dorsolateral to the ovary. The large-subunit rDNA (28S) Bayesian inference phylogenetic analysis (including 16 turtle blood fluke species of 7 genera) showed a strongly supported monophyletic Spirorchis MacCallum, 1918, grouping sister to Spirhapalum siamensis Tkach, Snyder, and Vaughn, 2009.

Publication Title

Comparative Parasitology

Volume

85

Issue

2

First Page

120

Last Page

133

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