Macvicaria kingscotensis, Aken'Ova & Cribb & Bray, 2008

Aken'Ova, Thelma, Cribb, Thomas & Bray, Rodney, 2008, Eight new species of Macvicaria Gibson and Bray, 1982 (Digenea: Opecoelidae) from temperate marine fishes of Australia, ZooKeys 1, pp. 23-58 : 51-54

Macvicaria kingscotensis n. sp.

Type-host: Neoodax balteatus Valenciennes (Odacidae) .

Other host: Haletta semifasciata (Valenciennes) (Odacidae) .

Type-locality: Off Kingscote, South Australia, 35°40’S, 137°39’E.

Other locality: Off American River, South Australia, 35°48’S, 137°46’E.

Site: Intestine.

Material Examined: Ex Neoodax balteatus : 6 from off Kingscote; Ex Haletta semifasciata : 2 from off American River, S.A, December 1995.

Type-material: Holotype: QM G230428 , paratypes: QM G230429-230432 , BMNH 2008.7.5.46-48 .

urn:lsid:zoobank.org:act:014A738F-826F-4F1A-B425-FEBFF266A8B0 Description ( Figs 37-42 )

Based on 5 gravid, unflattened whole-mount specimens and 1 set of serial sagittal sections from Neoodax balteatus . Measurements of worms from Haletta semifasciata are given in Table 4. Measurements are of the 5 gravid, unflattened, whole-mounts from Neoodax balteatus .

Body elongate, fusiform, maximum width in area of ventral sucker or gonads, 1,067 -1,447 (1,248) × 253-332 (282); width to length ratio 1:3.9-5.0 (4.4). Oral sucker ventrally subterminal, subglobular, 87-113 (97) × 101-118 (107). Ventral sucker larger than oral sucker, pre-equatorial, spherical to sub-spherical, 144-165 (155) × 155-188 (173); sucker width ratio 1:1.4-1.8 (1.6). Forebody contains numerous gland cells, 373-508 (425) long, 31-36 (34)% body-length. Prepharynx distinct, usually antero-dorsal to posterior margin of oral sucker, occasionally partially postero-dorsal. Pharynx large, sub-spherical, 53-65 (59) × 71-87 (77); pharynx to oral sucker width ratio 1:1.3-1.5 (1.4). Oesophagus distinct, well developed. Intestinal bifurcation in forebody, 114-180 (144) anterior to ventral sucker. Caeca terminate blindly close to posterior extremity.

Testes 2, entire, usually sub-spherical, occasionally irregular (n=1), contiguous, flattened at contiguity, tandem, in posterior half of body; anterior 120-165 (137) × 127-153 (144); posterior 159-203 (183) × 125-151 (134). Post-testicular space relatively short, 166-282 (217) long, 16-19 (17)% of body-length. Cirrus-sac clavate, long, thick walled, extends from point antero-sinistral to intestinal bifurcation to point level with or just posterior to ventral sucker aperture, 275-387 (322) × 43-51 (47). Internal seminal vesicle long, tubular; sinuous, looped and narrow at anterior end, broader at posterior end; occupies posterior portion of cirrus-sac. Pars prostatica distinct, narrow, surrounded by gland cells. Ejaculatory duct relatively long, thick walled, surrounded by gland cells. Genital atrium small. Genital pore extra-caecal, antero-sinistral to intestinal bifurcation, 168-222 (194) from anterior end, 15-16 (15.6)% of body-length.

Ovary usually entire, occasionally indistinctly lobed (n=1), sub-spherical, contiguously antero-dextral to anterior testis, flattened at contiguity, 98-108 (104) × 66-104 (84). Mehlis’ gland distinct, dorso-sinistral to ovary. Canalicular seminal receptacle large, saccular, dorsal to ovary, overlapping anterior margin of anterior testis. Laurer’s canal present. Uterus usually coils between point ventral and posterior to, or ventral to anterior margin of anterior testis and posterior margin of ventral sucker overlapping caeca and lateral and anterior margins of ovary, sometimes overlapping posterior margin of ventral sucker to its aperture (n=2), leads to genital pore without coiling. Metraterm distinct, surrounded by gland cells. Eggs large, oval, operculate, tanned, 59-83 (72) × 29-47 (35). Vitelline follicles extend from 159-216 (191) from anterior extremity, 13-20 (15)% of body-length, to 31-76 (46) from posterior extremity, with bilateral interruption in ventral sucker area; fields confluent dorsally and ventrally in post-testicular area and in forebody dorsally, separate ventrally in forebody; follicles lie lateral, ventral and dorsal to caeca; anterior limit may be just anterior to posterior end of oesophagus or posterior margin of pharynx or occasionally anterior to anterior margin of pharynx (n=1).

Excretory pore terminal. Excretory vesicle I-shaped; short terminal portion narrow, surrounded by few gland cells; anterior portion widens and passes anteriorly to point just posterior to anterior margin of anterior testis.

Etymology: This species is named after its type locality, Off Kingscote in South Australia.

Comments: The worms from Neoodax balteatus are metrically very similar to those from Haletta semifasciata , but they are longer and more slender, having non-overlapping width to length ratios of 1: 3.9-5.0 (4.4) versus 3.3-3.4 (3.4), respectively. This difference could have been induced by fixation or the host in either case.

Macvicaria kingscotensis n. sp. has the morphological features of the worms in Group D, as outlined above. It can be distinguished from the other worms in Group D as follows:

M. antarctica has a smaller pharynx, its pharynx to oral sucker width ratio being 1:1.8-2.2 (1.92), a shorter forebody measuring 25% of the body-length, smaller eggs measuring 42-51 × 20-28 and a genital pore which is slightly more anteriorly situated.

M. adomeae can be distinguished by its larger ventral sucker which is reflected in a sucker width ratio of 1:1.8-1.9 (1.9) and by its fusiform body-shape.

M. georgiana has vitelline fields reaching the pharynx, a saccular internal seminal vesicle, a shorter forebody (according to the illustrations in Zdzitowiecki, 1997) and small knobs on the anopercular pole of the eggs.

M. heronensis has a larger ventral sucker, with a sucker width ratio of 1:1.9, slightly longer eggs at 68-84 × 29-32 (76 × 31), a genital pore situated slightly more anteriorly (12.4% of the body-length from the anterior extremity) and the ovary is more distant from the ventral sucker.

M. muraenolepidis has a saccular internal seminal vesicle and small eggs (36-50 × 21-32) with small anopercular knobs.

Figures

Figs 37-39. Macvicaria kingscotensis n. sp. ex Neoodax balteatus. 37. Whole-mount ventral view. 38.Terminal genitalia. 39. Dorsal distribution of vitelline follicles. Scale bars: 37, 39, 250 µm; 38, 100 µm.

Figs 40-42. Macvicaria kingscotensis n. sp. ex Haletta semifasciata. 40. Whole-mount ventral view. 41.Terminal genitalia. 42. Dorsal distribution of vitelline follicles. Scale bars: 40, 42, 250 µm; 41, 100 µm.

Tables

Table 4. Measurements (in µm) of Macvicaria kingscotensis n. sp. from Haletta subfasciatus (n=2).

Total length	Min.	Max.	Mean
	844	971	908
Maximum width	258	283	271
Length/width	3.3	3.4	3.4
Oral sucker length	80	80	80
Oral sucker width (OSW)	92	95	94
Pharynx length	48	53	51
Pharynx width	62	65	64
OSW/pharynx width	1.4	1.5	1.5
Ovary length	80	81	80.5
Ovary width	61	68	65
Anterior testis length	104	107	106
Anterior testis width	109	109	109
Posterior testis length	127	137	132
Posterior testis width	117	119	118
Forebody-length (FBL)	301	301	301
FBL as % of body-length	31.0	35.7	33.3
Ventral sucker length	141	144	143
Ventral sucker width (VSW)	127	148	138
VSW/OSW	1.4	1.6	1.5
Anterior extremity to genital pore (AEGP)	152	153	153
AEGP as % body-length	15.7	18.1	16.9
Cirrus-sac length	237	237	237
Cirrus-sac width	47	47	47
Intestinal bifurcation to ventral sucker	93	93	93
Post-testicular region (PTR)	153	156	155
PTR as % of body-length	15.8	18.5	17.1
Anterior extremity to vitellarium (AEV)	150	163	157
AEV as % of body-length	16.8	17.8	17.3
Posterior extremity to vitellarium	41	43	42
Eggs	71-77 (76) × 32-37 (34), n=5