Athesmia ralli, Dronen, 2014

Dronen, Norman O., 2014, Keys to the species of Athesmia Loss, 1899 (Digenea: Dicrocoeliidae: Dicrocoeliinae), with the description of a new species from the clapper rail, Rallus longirostris Boddaert (Gruiformes: Rallidae), from Galveston, Texas, U. S. A., Zootaxa 3815 (3), pp. 342-352 : 343-345

Athesmia ralli n. sp.

( Figs. 1–3 )

Type host: The clapper rail, Rallus longirostris Boddaert ( Gruiformes : Rallidae ).

Type locality: Galveston County, Texas, USA, 29 22’ N, 94 34’ W .

Site if infection: Liver

Deposited specimens: Holotype USNPC 107956.00; paratype USNPC 107956.00; voucher USNPC 78466 .00.

Etymology: The species is named for the genus of the species of bird from which the new species was collected, Rallus Linnaeus.

Description: Based on six adult specimens. With characteristics of genus. Body attilae type, relatively large, slender, elongate, aspinose, holotype 11,150 (range 8,978 –11,150; mean 9,709) by 1,200 (1,200–1,450; 1,283); forebody 1,500 (1,475–1,573; 1,516) long, 13% (13–16%; 15%) of body length. Mouth subterminal, 410 (360–415; 385) by 388 (360–388; 369); preoral lobe present, 40 (20–40; 35) long; prepharynx absent; pharynx spherical to nearly circular, 110 (110–120; 115) by 130 (120–130; 125); esophagus long, 440 (400–440; 420) long, 4% (4–5%; 4%) of body length; cecal bifurcation near midlevel of forebody; ceca reaching well posterior to ovary, occupying 55% (55–70%; 62%) of postovarian space. Ratio of widths of oral sucker and pharynx 1:3.0 (1:2.3–1:3.5; 1:2.8). Ventral sucker located 1/6 distance down body, smaller than oral sucker to about same size, 380 (335–380; 365) by 395 (350–395; 378). Ratio of sucker widths 1:1.0 (1:0.9–1:1.5; 1: 1.1).

Testes lobed, tandem, situated near midlevel of upper 1/2 of body. Anterior testis 710 (470–990; 727) by 620 (540–620; 573); posterior testis 910 (480–910; 650) by 600 (600–720; 653). Cirrus sac medial, situated between cecal bifurcation and ventral sucker, enclosing short cirrus, reduced pars prostatica, short ejaculatory duct surrounded by prostate cells, and slightly coiled seminal vesicle, 330 (330–370; 343), 3% (3–4%; 4%) of body length) by 150 (120–150; 134) wide. Genital pore immediately postbifurcal on midline of body.

Ovary lobed, posttesticular, situated a short distance posterior to midlevel of body, 230 (170–230; 210 by 420 (335–435; 400), postovarian space 5,723 (4,825–5,723; 5,141) long, 51% (51–54%; 53%) of body length. Seminal receptacle spherical, saccate, located immediately posterior and dextral to ovary, 184 (164–270; 206) by 150 (110–150; 133). Laurer’s canal present, arising from oviduct across from seminal receptacle, proceeding sinistral towards midline of body, opening not observed. Single vitelline field (vitellarium) present on right side of body, locates in upper half of posterior half of body, dendritic, relatively large, 2,075 (2,075–2,250; 2,150) by 475 (175–475; 335), distributed along right cecum from level of oötype posteriorly to a short distance anterior to cecal ends in hindbody. Oötype some distance posterosinistral to ovary, located immediately anterior and dextral to anterior end of vitelline field. Uterus largely postacetabular, filling most of hindbody; descending limb proceeding posteriorly from ovary to posterior end of body, then turning anteriorly; ascending limb proceeding between vitelline field and ovary, then passing between the testes, proceeding anteriorly past ventral sucker to genital pore. Eggs numerous, operculate, 41–47 (40–47; 44) by 21–28 (21–29; 26) (n = 40) measured from distal end of uterus. Excretory vesicle I-shaped; excretory pore slightly subterminal.

Remarks: Athesmia ralli n. sp. has both of the ceca surpassing the level of the posterior margin of the vitelline field, terminating near the anterior extent of the posterior fifth of the body; thus it is assigned to the attilae type. The new species can be separated from all the other species assigned to the attilae type except A. butensis ( A. attilae , A. pricei , A. reelfooti , A. wehri ) by having eggs that were 40 or longer. The new species differs from A. butensis by having a longer distance from posterior testis to ovary (600–790 compared to less than 200), which represent a larger percentage of the total body length (7–8% compared to 2%), a larger maximum egg size (47 by 29 compared to 42 by 25), a somewhat larger body (8,978 –11,150 compared to 7,300), a longer forebody (1,500 –1,575, 13–16% of body length compared to 718, about 10%), vitelline field reaching posteriorly to the posterior third of the body rather than being confined to the middle third of the body as in A. butensis , and the new species is from rail from the Texas Gulf Coast rather than a hawk from the Archipiélago de Galápagos, Ecuador. The new species is somewhat similar to A. kassimovi in the heterolechithodes type, but further differs from this species by having a maximum egg size of 47 by 29 compared to 42 by 24, a larger space from the posterior testis to the ovary (695, representing 7–8% of body length compared to124, about 3%), a longer cirrus sac (350, representing 3–4% of body length compared to 220, 6%), a longer intertesticular space (382, representing 3–4% of body length compared to 230, 6%), and A. kassimovi is from a swamphen from the republic of Azerbaijan. Some authors (e.g. Panin 1984) consider Unilateralecithum Oshmarin, to be a synonym of Athesmia ; however, more recent authors (Lamothe- Argumendo, et al. 2005; Pojmaska 2008) consider these two genera to be separate. These two genera can be distinguished because species of Athesmia have a preequatorial placement of the ovary that is in close proximity to the testes rather than being situated postequatorial, some distance away from the testes, and the vitelline field in species of Athesmia is largely confined to the middle third of the body rather than being situated in the posterior half of the body. I agree with Lamothe-Argumendo, et al. (2005) and Pojmanska (2008) in the separation of these two genera.

Figures

FIGURES 1–3. Athesmia ralli n. sp. from the clapper rail, Rallus longirostris Boddaert (Gruiformes: Rallidae), from Texas. 1. Ventral view of fully mature adult. 2. Composite drawing of cirrus sac and seminal vesicle showing and cirrus and location of the genital pore, ventral view. 3. Composite drawing of female genital complex, ventral view.