Aptorchis megacetabulus Tkach et Snyder, 2007

Type host:

long-necked turtle, Chelodina rugosa Ogilby, 1890

Localities

Type locality: Daly River, near town of Daly River, Northern Territory, Australia, 13° 44.33’S, 130° 41.12’E

Other localities: Daly River, near Oolloo Crossing, Northern Territory, Australia, 14° 00.31’S, 131°14.46’E; Mary River, Opium Creek Station, Northern Territory, Australia, 12° 34.62’S, 131°43.48’E.

Type specimens:

Holotype: Queensland Museum (QM) no. G227476. Paratypes: QM no. G227477- G227478; Harold W. Manter Laboratory no. HWML48423-48425.

GenBank number: EF014730

Description (from Tkach and Snyder, 2007)

Description (based on 6 adult specimens): Measurements of the holotype are given in the text; measurements of the entire type series are given in the Table. Body elongate, widest at its midpoint; body length 860, body width at level of ventral sucker 230. Body width 26.7% of body length. Tegument thick, heavily armed at anterior end; spines decrease in size and density as they extend to posterior end. Oral sucker rounded, subterminal, 85 long x 95 wide, much smaller than rounded ventral sucker, 180 x 185. Ventral sucker situated in middle of body, surface covered with minute spines with 2 rings of larger spines at the periphery. Oral sucker/ventral sucker width 51.3%.

Prepharynx 60 long, widening posteriorly. Muscular pharynx, 75 long x 77.5 wide. Esophagus very short, sometimes almost indistinct, 10. Esophagus is surrounded by a group of single-cell glands. Intestinal bifurcation 250 from anterior end of body. Ceca nearly reach the posterior end of body terminating 65 from end.
Testes 2, rounded, oblique, postovarian, ventral to ceca in posterior third of body, midway between ventral sucker and posterior body end. Left testis usually anterior to right testis. Left testis 65 long x 50 wide, right testis 70 x 57. Cirrus sac very large, 248 long, ventral to ceca, arching extracecally along one lateral margin (usually right) of ventral sucker. Base of cirrus sac just posterior or at level of posterior margin of ventral sucker. Cirrus sac with bipartite internal seminal vesicle, very large pars prostatica and cirrus. Evaginated cirrus not observed. Genital pore submarginal, 315 from anterior end of body.

Ovary small, 60 long x 45 wide, median or slightly submedian, usually spherical, dorsal to ceca, situated just posterior to proximal part of cirrus sac, near posterior margin of ventral sucker. Vitellarium consists of small, irregularly shaped follicles, arranged in lateral fields partly overlapping ceca or extracecal. Vitelline fields extend posteriorly, 105 from posterior body end. Anteriorly, left vitelline field reaches 15 from posterior margin of ventral sucker, right vitelline field reaches 30 from posterior margin of ventral sucker. Vitelline fields not confluent. Seminal receptacle thick-walled, relatively large, 70 long x 60 wide, adjacent to ovary. Mehlis' gland ventral to seminal receptacle. Laurer's canal was not visible in total mounts. Uterus inter- and post-cecal, postacetabular; metraterm is approximately as long as cirrus sac. Metraterm passes dorsal to cirrus sac before it opens into genital atrium. Eggs operculate, 25 x 12.5. Excretory pore terminal; excretory vesicle reaches the level of ovary.

Illustrations

Authors: Vasyl V. Tkach, Scott D. Snyder, Yuriy Kuzmin