Transversotrema fusilieri

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 : 30-31

Transversotrema fusilieri n. sp

( Fig. 10 )

Type-host: Lutjanidae : Caesio cuning (Bloch) , Red-bellied fusilier.

Type-locality: Lizard Island, northern GBR, Queensland. Australia, (14°40’S 145°28’E)

Other hosts: Lutjanidae : Caesio caerulaurea (Lacepède) , Scissortail fusilier.

Site: Beneath the scales

Material examined: Table 6

Molecular sequence data: ITS2 rDNA

GenBank accession numbers: Table 2

Deposited specimens: Holotype QMG 231865 (ex Caesio cuning coll. Cribb et al. Jun 2005) and paratypes QMG 231866 (ex Caesio cuning coll. Cribb et al. Jun 2005), QMG 231867 (ex Caesio cuning coll. Cribb et al. Jun 2005), QMG 231868 (ex Caesio caerulaurea coll. Cribb et al. Jun 2005), QMG 231869 (ex Caesio caerulaurea coll. Cribb et al. Jun 2005).

Etymology: Caesionines are commonly named fusilier fish hence the name for this species.

Description: Based on measurements of 8 specimens from lutjanines ( Caesioninae ) from Lizard Island. Body transversely elongated, curved at extremities, strongly dorsoventrally flattened, 412–638 (468) long, 1,294–2,222 (1,688) wide; width/length range 3:1. Posterior margin wider than anterior margin. Pharynx to anterior margin 140–203 (168); cyclocoel to posterior margin at midline 70–117 (91). Tegumental spines prominent. Eyespots prominent, 70–210 (137) apart, average 8% of body width; anterior to pharynx; no pigment evident other than in eyespots. Ventral sucker posterior to eyespots, 2,203–2,864 (2,446) μm2. Mouth mid-ventral, inconspicuous. Pharynx between and slightly posterior to eyespots, 51–72 (61) long, 61–81 (71) wide. Oesophagus curved. 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 12,123–34,445 (19,298) μm2; right 13,169–17,199 (14,971) 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 extended lobes, 3,696–8,302 (5,747) 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, no follicles extend beyond lateral margin of cyclocoel along anterior margin; posterior follicles in rows of two or three. Enclosed follicles in two loosely assembled masses at each lateral extremity, 21–46 (37); follicles not 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 75–130 (109.5) long, 58–75 (71.5) wide; 2–6 (4) 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 fusilieri n. sp. is one of two species found from caesionine fishes from Lizard Island and Ningaloo. This species is more similar to T. licinum in overall body shape but is oval rather than crescent-shaped. The length and width of this species overlap the dimensions of T. licinum as described by Manter (1970) (p. 486) however the ventral sucker, oesophagus and pharynx are all smaller. Further, the distance from the cyclocoel to the posterior margin ranges from 140–203 µm in T. fusilieri n. sp. but reaches only 107 µm in T. licinum . In comparison to T. atkinsoni n. sp., T. borboleta n. sp., T. carmenae n. sp., T. damsella n. sp., and T. espanola n. sp., this species from caesionines has a smaller ventral sucker, and also smaller testes and ovary than all with the exception of T. atkinsoni n. sp. and T. damsella n. sp. Sequence data separates T. fusilieri n. sp. from all other transversotrematid species and whilst morphological differences are subtle, morphometric variation and molecular divergence confirm the differentiation of this species from all others.

Figures

FIGURE 10. Transversotrema fusilieri n. sp. ex Caesio cuning Lizard Island. Scale = 200 μm.