Biospeedotrema parajolliveti, Bray, R. A., Waeschenbach, A., Dyal, P., Littlewood, D. T. J. & Morand, S., 2014

Bray, R. A., Waeschenbach, A., Dyal, P., Littlewood, D. T. J. & Morand, S., 2014, New digeneans (Opecoelidae) from hydrothermal vent fishes in the south eastern Pacific Ocean, including one new genus and five new species, Zootaxa 3768 (1), pp. 73-87 : 76

Biospeedotrema parajolliveti n. sp.

( Figs. 2 )

urn:lsid:zoobank.org:act:4B22B98B-50F4-4D19-AA2D-7D47776CCD29

Type host. Thermichthys hollisi (Cohen, Rosenblatt & Moser) (Ophididiiformes: Bythitidae ), Hollis brosmekvabbe.

Site. Large intestine and gall-bladder.

Type locality. South East Pacific Rise, hydrothermal vent site Hobbs, 17°35.20’S, 113°14.75’W; Biospeedo cruise, PL 1588, depth 2598 m, baited trap, 29 Apr. Biospeedo labels: 1588–1, 1588–3.

Type specimens. MNHN holotype 1 slide MNHN HEL 382, paratypes 4 wholemount slides, MNHN HEL 383 384 385 386, 4 section slides MNHN HEL 387 388 389 390; BMNH paratypes 2013.12.3.1-3.

Etymology. This species is named to emphasise its similarity to Biospeedotrema jolliveti .

Description. Based on 8 wholemount specimens and 2 sets of serial sections. Measurements and ratios in Table 1. Many features difficult to see in wholemounted specimens. Body small, broadly oval, distinctly wider than long ( Fig. 2 ). Tegument unarmed. Oral sucker transversely elongate oval, more or less terminal. Ventral sucker rounded to oval, larger than oral sucker, just-pre-equatorial. Prepharynx very short, dorsal to oral sucker. Pharynx large, oval. Oesophagus distinct, sinuous, thin-walled. Intestinal bifurcation dorsal to ventral sucker. Caeca blind, wide, divergent, almost or just reaching to testes.

Testes two, irregular, symmetrical, separated in anterior hindbody. Cirrus sac claviform, reaches dorsally to ventral sucker. Internal seminal vesicle saccular. Pars prostatica short. Ejaculatory duct long, muscular. Genital atrium small. Genital pore median, about mid-way between suckers, but not clear in wholemounts.

Ovary subglobular, just anterior to right testis, overlapping ventral sucker. Seminal receptacle uterine. Laurer’s canal opens dorsally in anterior hindbody. Mehlis’ gland not detected. Uterus reaching between testes, or just into post-testicular region, then passes over dorsal surface of ventral sucker. Eggs large, tanned, operculate, relatively few. Metraterm not distinct. Vitellarium follicular, in narrow arcuate lateral fields from pharynx or oesophagus to testicular level, mainly lateral to caeca, but encroaching dorsally.

Excretory pore terminal. Vesicle short, I-shaped, reaches to uterus, not traced further.

Remarks. This species appears to be a squat version of B. jolliveti , and differs in that it is always just wider than long, the tegument is wrinkled, the testes are lobate, and the caeca at their longest, only just reach to the testes (Table 1).

Figures

FIGURES 1 – 4. 1. Biospeedotrema jolliveti n. sp. ventral view of holotype. 2. Biospeedotrema parajolliveti n. sp., ventral view of holotype. 3. Biospeedotrema biospeedoi n. sp. a. Ventral view of holotype. b, c. Illustration of variation in body-shape. 4. Caudotestis ventichthysi. n. sp. Ventral view of holotype, cirrus-sac obscured by eggs. Abbreviations: C, caecum; CS, cirrussac; E, egg; Ov, ovary; T, testis; V, vitelline follicle. Scale-bars: 1, 3 a, b, c, 4, 200 µm; 2, 100 µm.