Transversotrema lacerta, Hunter & Ingram & Adlard & Bray & Cribb, 2010

Hunter, J. A., Ingram, E., Adlard, R. D., Bray, R. A. & Cribb, T. H., 2010, A cryptic complex of Transversotrema species (Digenea: Transversotrematidae) on labroid, haemulid and lethrinid fishes in the Indo-West Pacific Region, including the description of three new species, Zootaxa 2652 (1), pp. 17-32 : 28

Transversotrema lacerta n. sp.

( Fig 5 )

Type host: Lethrinus atkinsoni Seale Lethrinidae . Yellowtailed Emperor.

Type locality: Lizard Island , northern Great Barrier Reef (Queensland, Australia) .

Other hosts: Lethrinus nebulosus (Forsskål) (Lethrinidae) , Spangled Emperor; Diagramma labiosum Macleay (Haemulidae) Painted sweetlips. Lizard Island.

Site of infection: Beneath the scales.

Materials examined: 60 individuals from haemulids and 36 from lethrinids (see Table 3).

GenBank: see Table 2.

Deposited specimens: Holotype and paratypes Queensland Museum G 231803 – G231808

Etymology: The type host of this transversotrematid is from Lizard Island. The Latin word for lizard is lacerta and the name distinguishes this group from the others which are found from Heron Island.

Description: (based on measurements of nine specimens from lethrinids from Lizard Island). Body transversely elongated, strongly dorsoventrally flattened, 380–650 (559) µm long, 980–2000 (1538) µm wide, width/length ratio 2.57–3.07 (2.75). Tegumental spines prominent. Eyespots prominent, 290–430 (345) µm apart, 20–30.6 (25.8%) body width; no pigment evident other than in eyespots. Ventral sucker well posterior to eyespots, 71–173 (114) µm long, 77–177 (116) µm wide. Mouth mid-ventral, inconspicuous. Pharynx between or slightly posterior to eyespots, 90–241 (158) long, 93–226 (155) wide. Oesophagus distinct, winding 135–381 (253) long. Caecal bifurcation anterior or dorsal to ventral sucker. Caeca form cyclocoel reaching laterally to envelop testes, ovary and some vitelline follicles. Testes opposite, deeply lobed, left, 168–452 (359) long, 168–561 (382) wide; right 161–477 (342) long, 190–600 (391) wide. 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 dust 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 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, deeply lobed, 84–394 (217) long, 97–380 (227) wide. Oviduct passes medio-posteriorly, unites with Laurer’s canal and duct from oviduct passes vitelline reservoir. Laurer’s canal passes posteriorly to open dorsally close to left testis; median portion dilated, contains sperm or vitelline remnants. Vitelline reservoir immediately anterior to left testis. Vitelline follicles in extracaecal space quite sparse in the anterior margin; enclosed follicles in 2 masses at each lateral extremity, 11–32 (18). 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 large, 91–130 (107) long, 33–73 (52) wide. Excretory pore opens posteriorly at small notch in middle of posterior margin, bladder extends anteriorly in initially narrow tube which then expands into large sac which passes ventral to cyclocoel anterior to which it becomes laterally directed.

Figures

FIGURE 5. Transversotrema lacerta n. sp. ex Lethrinus atkinsoni, Lizard Island, northern Great Barrier Reef. Scalebars = 500 µm.