Transversotrema witenbergi, Hunter, Janet A. & Cribb, Thomas H., 2012

Hunter, Janet A. & Cribb, Thomas H., 2012, A cryptic complex of species related to Transversotrema licinum Manter, 1970 from fishes of the Indo-West Pacific, including descriptions of ten new species of Transversotrema Witenberg, 1944 (Digenea: Transversotrematidae), Zootaxa 3176, pp. 1-44 : 34-35

Transversotrema witenbergi n. sp.

( Fig. 13 )

Type-host: Lutjanidae : Pterocaesio marri (Schultz) , Marr’s fusilier Type-locality: Heron Island, southern GBR, Queensland, Australia. (23°27’S 151°55’E). Other hosts: Lutjanidae Caesio cuning (Bloch) , Red-bellied fusilier. Site: Beneath the scales

Materials examined: Table 6

Molecular sequence data: ITS2 rDNA

GenBank accession numbers: see Table 2

Deposited specimens: Holotype QM G321876 (ex P. marri HI coll. Cribb et al. 25 Feb 2006) and paratypes QM G321877 (ex P. marri HI coll. Cribb et al. 25 Feb 2006), QM G321878 (ex C. cuning HI coll. Ingram 3 May 2003), QM G321879 (ex C. cuning HI coll. Cribb et al. 25 Feb 2006).

Etymology: The first adult transversotrematid was discovered from Red Sea fishes in 1944 by Witenberg. This species is named in his honour.

Description: Based on measurements of 20 specimens from lutjanines ( Caesioninae ) from Lizard Island. Body transversely elongated, curved at extremities, strongly dorsoventrally flattened, 335–488 (468) long, 1084–1913 (1688) wide; average width/length range 3.6:1. Pharynx to anterior margin 121–152 (146), cyclocoel to posterior margin at midline 52–84 (69). Posterior margin wider than anterior margin. Tegumental spines prominent. Eyespots prominent, 104–181 (144) apart, average of 9% of body width; anterior to pharynx; no pigment evident other than in eyespots. Ventral sucker posterior to eyespots, 1,616–4,742 (3,133) μm2. Mouth mid-ventral, inconspicuous. Pharynx between and slightly posterior to eyespots, 68–108 (79) long, 47–123 (91) wide. Oesophagus curved. 71–91 (83). Caecal bifurcation dorsal to ventral sucker. Caeca form cyclocoel reaching laterally to envelop testes, ovary and some vitelline follicles. Margins of cyclocoel crenulated. Testes opposite, deeply lobed, left 8,902– 25,926 (16,144) μm2; right 7,226–24,513 (15,304 μm2). Seminal vesicle formed of lobed, saccular enclosed portion and winding, tubular extracaecal portion. Enclosed portion distinctly lobed or entire, antero-dextral to right of testis, constricts distally to form narrow duct that passes ventral to cyclocoel to join tubular portion. Tubular portion of seminal vesicle passes mediad along cyclocoel then turns anteriorly and passes between eyespots dextral to pharynx, loops and passes to common genital pore where it unites with uterus without any specialisation. Common genital pore precisely in midline on anterior margin of worm. Ovary sinistral to left testis, with five prominent extended lobes, 2,473–9,887 (4,945) μm2. Oviduct passes medio-posteriorly, unites with Laurer’s canal and duct from oviduct passes vitelline reservoir, Laurer’s canal then passes posteriorly to open dorsally close to left testis; median portion dilated, contains sperm or vitelline remnants. Vitelline reservoir immediately anterior to left testis. Extracaecal vitelline follicles numerous, confluent, lateral and posterior to cyclocoel, few follicles extend beyond lateral margin of cyclocoel into anterior margin; posterior follicles in rows of two or three. Enclosed follicles in two loosely assembled masses at each lateral extremity, 26–45 (33); follicles extending along posterior margin of cyclocoel posterior to testes. Uterus passes medially between anterior half of cyclocoel and testes then between right testis and saccular portion of seminal vesicle. Proximal portions of uterus act as seminal receptacle. Eggs 74–88 (79.2) long and 30–62 (49.6) wide, 1–8 (5) in utero. Excretory bladder opens posteriorly at small notch in middle of posterior margin, extends anteriorly in initially narrow tube which then expands into large sac which passes ventral to cyclocoel anterior to which it becomes laterally directed.

Remarks: Transversotrema witenbergi n. sp. resembles T. licinum but is spindle-shaped rather than crescentshaped, it is widest at the equator and the lateral margins are not curved upwards. The distance between the cyclocoel and the posterior edge at the midline is shorter in T. witenbergi n. sp. than in T. licinum . The overall body shape of T. witenbergi n. sp. is different from that of the T. manteri n. sp. and T. fusilieri n. sp. from caesionines from Lizard Island and Ningaloo. These three species from caesionines have smaller ventral suckers and gonads than do transversotrematids from non-caesionine hosts and these characters for T. witenbergi n. sp. are smaller than T. manteri n. sp. and T. fusilieri n. sp. Transversotrema . atkinsoni n. sp., a species found from Heron Island nemipterids, is different from T. witenbergi n. sp. in shape and size. The range and average size of the ventral sucker of T. atkinsoni n. sp. is much greater than that recorded in T. witenbergi n. sp. The third species from Heron Island, T. espanola n. sp. from lutjanid hosts, is readily distinguished from T. witenbergi n. sp. by overall shape, the distribution of vitelline follicles at the posterior margin and the greater size of the testes and ovary. Genetic data and the morphometric data combined show that T. witenbergi n. sp. is distinguishable from all other T. licinum -form transversotrematids.

Figures

FIGURE 13. Transversotrema witenbergi n. sp. ex Pterocaesio marri Heron Island. Scale = 200 μm.