Macvicaria mutovitellina Aken' Ova, Cribb & Bray 2008

Based on 13 gravid, whole-mount specimens and 1 set of serial sagittal sections. Measurements are of 10 gravid, unflattened, whole-mount worms. Body robust, elongate-oval, sub-cylindrical, tapered at anterior end, rounded at posterior end, lateral margins roughly parallel, 833-1,108 (962) × 296-393 (349); width to length ratio 1:2.5-3.0 (2.8). Oral sucker almost terminal, subglobular, 95-123 (110) × 116-148(131). Ventral sucker larger than oral sucker, transversely oval, 183-228 (203) × 207-261 (228); sucker width ratio 1:1.6-1.9 (1.7). Forebody contains few large and numerous small gland cells, 227-281 (261) long, 25-29 (27)% body-length. Prepharynx distinct, short, partly posterior and partly dorsal to oral sucker. Pharynx large, sub-spherical, 63-80 (71) × 71-99 (81); pharynx to oral sucker width ratio 1:1.5-1.8 (1.6). Oesophagus distinct, short, thick walled. Intestinal bifurcation usually dorsal to anterior half of ventral sucker, 15-29 (21) posterior to anterior margin of ventral sucker, sometimes level with (n=4), and occasionally just anterior to anterior margin ventral sucker (n=1). Caeca terminate blindly close to posterior extremity. Testes 2, transversely oval, tandem, contiguous, entire, anterior 101-159 (122) × 136-190 (172), posterior 133-167 (148) × 151-188 (174). Post-testicular area 138-246 (180) long, 15-22 (19) % body-length. Cirrus-sac large, clavate, thick walled especially at posterior extremity, extends from about level of posterior margin of pharynx to level of ovary or anterior testis; 306-388 (347) × 78-104 (88). Internal seminal vesicle convoluted, occupies posterior half or third of cirrus-sac. Pars prostatica distinct, well developed, surrounded by numerous gland cells. Ejaculatory duct long, convoluted at posterior end, thick walled, surrounded by few gland cells. Genital atrium small. Genital pore extra-caecal, antero-sinistral to intestinal bifurcation, usually anterior to posterior margin of pharynx, sometimes level with oesophagus (n=3), 169-231 (200) from anterior end, 20-22 (21)% of body-length. Ovary entire, spherical to sub-spherical, usually contiguous with anterior testis, sometimes separate (n=2), usually antero-dextral to anterior testis, occasionally dextral (n=1), 81-111 (94) × 89-112 (103). Mehlis’ gland distinct, sinistral to ovary, anterior to anterior testis. Canalicular seminal receptacle small, saccate, dorsal to anterior testis. Uterine coils usually extend from point just posterior to anterior margin of anterior testis to posterior margin of ventral sucker, overlapping left caecum ventrally and sometimes left side of ovary dorsally, occasionally coils extend to just anterior to posterior margin of anterior testis (n=1) or to posterior margin of posterior testis (n=1). Metraterm distinct, moderately long, well developed, overlaps left caecum to point just anterior to or just posterior to ventral sucker aperture. Eggs relatively large, tanned, usually few, oval, operculate, 54-71 (63) × 26-39 (31). Vitelline follicles extend from 173-314 (215) from anterior extremity, 17-34 (22)% body-length, to 8-19 (14) from posterior extremity; follicles in two separate fields in forebody ventrally, confluent in post-testicular area, covering almost all surface of posterior testis and posterior and or lateral portion of anterior testis and ovary ventrally; dorsal field almost confluent, interrupted in area of posterior half of ventral sucker, particularly in area of male terminal genitalia, sometimes follicles absent dorsally and ventrally (n=1) or feebly developed (n=2) in forebody; fields lie lateral, dorsal and ventral to caeca with unilateral or bilateral follicle-free patches in area of ventral sucker ventrally; anterior extent usually at level of posterior end of oesophagus, or posterior margin of pharynx, rarely at level of ventral sucker aperture (n=1). Excretory pore terminal. Excretory vesicle I-shaped, with narrow posterior end, broadens and extends anteriorly to point just posterior to anterior margin of anterior testis as seen in sagittal section. Etymology: The species name mutovitellina (L. muto, change; vitellus, yolk) is derived from the variable patterns of the distribution of vitelline follicles.

Type-host: Dactylophora nigricans (Richardson) (Cheilodactylidae). Type-locality: Off Point Peron, Western Australia 32°18’S, 115°38’E. Site: Intestine. Material studied: 14 Off Point Peron, December 1994. Type-material: Holotype: QM G230379, paratypes: QM G230380-230389, BMNH 2008.7.5.1-5.