Transversotrema tragorum, Hunter, Janet A., Hall, Kathryn A. & Cribb, Thomas H., 2012

Hunter, Janet A., Hall, Kathryn A. & Cribb, Thomas H., 2012, A complex of Transversotrematidae (Platyhelminthes: Digenea) associated with mullid fishes of the Indo-West Pacific Region, including the descriptions of four new species of Transversotrema, Zootaxa 3266, pp. 1-22 : 12-13

Transversotrema tragorum n. sp.

( Fig. 4 )

Type-host: Parupeneus indicus (Shaw) , Mullidae, Indian goatfish.

Site: beneath scales.

Type locality: off Lizard Island, northern Great Barrier Reef, Queensland, Australia (14°40´S 145°28´E).

Other hosts: Mullidae : Parupeneus barberinus (Lacepède) , dash-and-dot goatfish; Parupeneus ciliatus (Lacepède) , whitesaddle goatfish; Parupeneus cyclostomus (Lacepède) goldsaddle goatfish; Parupeneus multifasciatus (Quoy & Gaimard) , manybar goatfish; Parupeneus trifasciatus (Lacepède) , doublebar goatfish.

Prevalence: (see Table 4 )

Deposition of types: Holotype QM G231632 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 8 Apr. 2006); paratypes QM G231633 (ex P . barberinus, Lizard Island, coll. T. H. Cribb et al., 10 May 2004), QM G231634–635 (ex P. cyclostomus , Lizard Island, coll. T. H. Cribb et al., 5 Jun. 2007), QM G231636–637 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 4 Aug. 2002), G231638 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 8 Apr. 2006), G231639–640 (ex P . multifasciatus, Lizard Island, coll. T. H. Cribb et al., Jun. 2005); vouchers QM G231641 (ex P . cyclostomus, Lizard Island, coll. T. H. Cribb et al., 12 May 2004), G231642–645 (ex P . cyclostomus, Lizard Island, coll. T. H. Cribb et al., 31 May–5 Jun. 2006), G231646 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 4 Aug. 2002), G231647–657 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 8 Apr. 2006), G231658 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., Jun. 2007), G231659–660 (ex P . indicus, Lizard Island, coll. T. H. Cribb et al., 2007), G231661 (ex P . multifasciatus, Lizard Island, coll. T. H. Cribb et al., Jun. 2005).

Etymology: this species name is derived from tragos, the Greek word for goat.

Description: Based on 18 (17 mature, 1 immature) specimens. Body transversely elongated, dorsoventrally flattened, widest at anterior margin, 428–1,080 (720) µm long, 1130–2768 (1,850) µm wide; total body area 0.48–2.99 (1.40) mm2; body width/length ratio 2.3–2.9 (2.6). Tegument spined; spines prominent. Eyespots central in anterior half of body, 130–228 (190) µm apart; no pigment other than eyespots evident. Ventral sucker well posterior to eyespots, surface area 1,934–7,159 (3,937) µm2. Mouth inconspicuous, mid-ventral. Pharynx prominent, large, distinct, between or slightly posterior to eyespots, 47–131 (101) µm long, 50–147 (99) µm wide. Oesophagus short, straight 29–55 (38.2). Intestine present as cyclocoel, bifurcation dorsal to ventral sucker, caecum proceeds in a loop lateroanteriorly from central oesophagus to level of pharynx, immediately passes lateroposteriorly towards each lateral margin, and then follows contour of body margin, recurving posteriorly and passing medially to envelope gonads and some vitelline follicles. Testes paired, spheroid, deeply lobed, symmetrical, not contiguous; left testis surface area 10,143–53,140 (28,562) µm2; right testis surface area 9,836–52,026 (26,173) µm2. Seminal vesicle distinctly bipartite, composed of enclosed (by cyclocoel) and extracaecal portions; enclosed portion proximal to testes, saccular, distinctly lobed or entire, anterodextral to right testis, constricted distally to form narrow duct which passes ventral to cyclocoel and leads to extracaecal portion; extracaecal portion tubular, winding, long, passes laterally along line of cyclocoel towards midline of body, then turns anteriorly and proceeds between eyespots, dextral to pharynx, forms naked ejaculatory duct distally. Genital pore median, on anterior margin of body. Ovary deeply lobed, sinistral to, but not contiguous with, left testis, surface area 3,835–17,589 (10,432) µm2; oviduct passes medio-posteriorly from ovary. Seminal receptacle uterine. Laurer’s canal unites with oviduct posterior to ovary, passes and joins vitelline reservoir further posteriorly, before opening dorsally, close to left testis, median portion of canal dilated, contains sperm and vitelline remnants. Uterus passes medially between anterior half of cyclocoel and testes, proceeds between right testis and saccular portion of seminal vesicle, then proceeds anteriorly to pass over cyclocoel and join ejaculatory duct at common genital pore; termination of uterus unspecialised. Vitellarium follicular; vitelline follicles dense, scattered in extracaecal and enclosed areas of body; extracaecal follicles fill posterior region of body, extend laterally to anterior portion of body, but never reach anterior margin, neither are they scattered at anterior margin nor in median portion of anterior part of body; enclosed follicles in two masses, one mass in each lateral portion of enclosed area, sometimes also scattered in interrupted band along inner posterior margin of cyclocoel, follicles number 33–62 (53). Vitelline reservoir immediately anterior to left testis. Eggs tanned, no operculum observed, unembryonated in utero, few, 3–12 (6) per individual. Excretory bladder saccular, opens posteriorly at small notch in middle of posterior margin, extends anteriorly in initially narrow tube; tube expands distally into large sac which lies largely ventral to cyclocoel, laterally directed anterior to posterior loop of cyclocoel.

Molecular data: Sequence data were obtained from the 28S region of four specimens infecting P. trifasciatus , P. ciliatus , P. indicus and P. multifasciatus ; from the ITS1 region of four specimens parasitising P. trifasciatus , P. ciliatus , P. cyclostomus and P. indicus ; and from the ITS2 region of 16 from P. barberinus (1), P. trifasciatus (2), P. ciliatus (1), P. cyclostomus (3), P. indicus (4) and P. multifasciatus (5) ( Table 2 ).

Remarks: Specimens of T. tragorum n. sp. resemble the complex of species related to T. licinum characterised by Hunter & Cribb (2012) in that the vitelline follicles do not extend across the anterior margin of the body. However, T. tragorum n. sp. has a strongly D–shaped body outline not seen in specimens from the T. licinum complex. The ejaculatory duct of T. licinum complex species is coiled, differing from that of T. tragorum n. sp. which has a single loop. In addition, the oesophagus of T. licinum complex species is relatively winding, whereas that in T. tragorum n. sp. is so short that the cyclocoel joins almost directly to the pharynx. The lack of vitelline follicles in the anterior parts of the body distinguishes this species from T. cabrarum n. sp., T. chevrarum n. sp., T. elegans , T . gigantica, T . haasi and T. lacerta . Transversotrema tragorum n. sp. is much larger than T. cutmorei n. sp. in all measurements and the overall body shape is more strongly D–shaped and less angular at the margins. Finally, molecular data (see below) distinguish T. tragorum n. sp. from all other species from mullid fishes and from the transversotrematid species characterised by Hunter et al. (2010) and Hunter & Cribb (2012).

Figures

FIGURE 4. Transversotrema tragorum n. sp. ex Parupeneus indicus Lizard Island. GBR. Scale = 500 µm.