Platyhelminths of Nebraska Turtles with Descriptions of Two New Species of Spirorchiids (Trematoda: Spirorchiidae)

Abstract

Twenty-one species of platyhelminth parasites are reported from 8 species of turtles collected in Nebraska. Two species of spirorchiids are reported as new. Vasotrema brevitestis sp. n. from Trionyx muticus and T. spiniferus differs from V. amydae Stunkard, 1926, in possessing a relatively shorter, more compact testis, postcecal length equal to one-fifth the body length, a cirrus sac which does not extend to the opposite cecum, and vitellaria composed of discrete follicles more restricted in distribution. Hapalorhynchus foliorchis sp. n. from Chelydra serpentina differs from H. gracilis Stunkard, 1922, in possessing a narrower oral sucker and larger acetabulum, a prominent esophageal constriction, smaller ovary and larger, irregular testes, postcecal space equal to one-sixth the body length, and ventrally oriented uterus. Five other species, Allassostomoides chelydrae, Diarmastorchis blandingi, Vasotrema amydae, V. attenuatum, and Ophiotaenia testudo, are reported for the first time since their description. Nineteen species are reported from Nebraska for the first time. New host records are Trionyx muticus for Vasotrema attenuatum and V. robustum and Graptemys pseudogeographica (Gray) for Allassostomoides chelydrae. From June 1973 until October 1974, the authors collected 16 species of platyhelminths from 55 turtles representing seven species captured in Nebraska (Table I). The results were combined with unpublished data compiled by H. W. Manter for the period 1947-49, bringing the total to 21 species of worms from eight species of turtles. Two species of spirorchiid trematodes are described as new. Spirorchiids were killed with hot water and immediately transferred to AFA. Other worms were flattened with slight coverslip pressure and fixed with AFA. All were stored in 70% ethanol; stained with Mayer's carmalum, Mayer's hematoxylin, or Delafield's hematoxylin; and mounted in Canada balsam. Figures were drawn with the aid of a camera lucida. All measurements are in microns. Dimensions of organs are stated as length by width. Family Spirorchiidae Stunkard, 1921 Vasotrema brevitestis sp. n. (Fig. 1) Description (measurements based on 20 of 34 specimens): Body spindle-shaped, weakly muscled; length 1,300 (1,246 to 1,428), width 115 (108 to 124). Small spines present on anterior end of body, most conspicuous on oral sucker. Oral sucker subReceived for publication 25 November 1974. * Present address: Gulf Coast Research Laboratory, P.O. Box A. G., Ocean Springs, Mississippi 39564. terminal, oval, diameter 50 (40 to 56); acetabulum at anterior end of second third of body, round, diameter 50 (38 to 52). Esophagus 190 long, with ring of prominent diverticula at beginning of posterior third of esophagus. Intestinal bifurcation preacetabular, ceca relatively long; postcecal space one-fifth body length. Testis relatively short, compact, exhibiting some degree of torsion; intercecal at mid-hindbody; 260 (231 to 310) by 90 (70 to 100); ratio of testis length to body length 1:5. Vas deferens straight, passing lateral or dorsal to ovary. Seminal vesicle external, saccular, connected to cirrus sac by short duct. Cirrus sac short, diagonal, not extending to opposite cecum, 72 (66 to 78) by 12 (11 to 12); containing pars prostatica and straight cirrus. Genital pore ventral, posterosinistral to acetabulum. Ovary pretesticular, round to slightly irregular, 40 by 38 (34 to 40). Seminal receptacle postovarian, large, filling intercecal space between ovary and testis. Laurer's canal short; Mehlis' gland composed of very small cells. Uterus saccular, preovarian, sinistral, opening at genital pore. Vitelline follicles discrete, 20 to 40 in number, 12 in diameter; most numerous in region of seminal receptacle, extending dorsally from testicular to acetabular region. Single mature egg 20 by 16; single immature egg 36 by 30. Excretory pore terminal, vesicle convoluted in postcecal region. Type host: Trionxy muticus (LeSueur), smooth soft-shelled turtle. Type locality: Missouri River, 1.5 miles south of Blair, Nebraska. Another host and locality: T. spiniferus (LeSueur), spiny soft-shelled turtle, Atkinson State Recreation Area, 0.5 mile west of Atkinson, Nebraska. Type specimens: Holotype and two paratypes