Transversotrema chevrarum, 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 : 8-10

Transversotrema chevrarum n. sp.

( Fig. 2 )

Type-host: Parupeneus ciliatus (Lacepède) , Mullidae , whitesaddle 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 cyclostomus (Lacepède) goldsaddle goatfish; Parupeneus indicus (Shaw) , Indian goatfish; Parupeneus multifasciatus (Quoy & Gaimard) , manybar goatfish; Parupeneus trifasciatus (Lacepède) , doublebar goatfish.

Prevalence: see Table 4 .

Deposition of types: Holotype QM G231662 (ex P. ciliatus Lizard Island, coll. T. H. Cribb, 12 Dec. 2002); paratypes QM G231663 (ex P . barberinus Lizard Island, coll. T. H. Cribb et al., 1 Aug. 2002), QM G231664 ex P . trifasciatus Lizard Island, coll. T. H. Cribb et al., 5 Jun. 2007), QM G231665 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 12 Dec. 2002); QM G231666 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 2 Jun. 2007); QM G231667 (ex P . indicus Lizard Island, coll. T. H. Cribb, 2 Jun. 2007); QM G231668–670 (ex P . multifasciatus Lizard Island, coll. T. H. Cribb, 11 May 2004); vouchers QM G231671–673 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 12 Dec. 2002); QM G231674 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 4 Aug. 2002); QM G231675–676 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 2 Jun. 2007); QM G231677 (ex P . ciliatus Lizard Island, coll. T. H. Cribb, 7 Jul. 1995); QM G231678 (ex P. indicus Lizard Island, coll. T. H. Cribb, 4 Aug. 2002); QM G231679–680 (ex P . multifasciatus Lizard Island, coll. T. H. Cribb, 11 May 2004); QM G231682–683 (ex P . multifasciatus Lizard Island, coll. T. H. Cribb, 1 Jun. 2007); QM G231684 (ex P . multifasciatus Lizard Island, coll. T. H. Cribb, 3 Jun. 2007).

Etymology: this species name is derived from the modern French chèvre (f.), meaning “she-goat”.

Description: Based on 17 (16 mature, 1 immature) specimens. Body transversely elongated, D–shaped, dorsoventrally flattened, widest at equator, 461–1,013 (705) µm long, 1,251–2,752 (1802) µm wide; total body area 0.58–2.79 (1.33) mm2; body width/length ratio 2.3–2.9 (2.6). Tegument spined; spines prominent. Eyespots central in anterior half of body, 119–258 (172) µm apart; no pigment other than eyespots evident. Ventral sucker well posterior to eyespots, surface area 2,740–6,209 (4191) µm2. Mouth inconspicuous, mid-ventral. Pharynx prominent, large, between or slightly posterior to eyespots, 61–147 (95) µm long, 71–127 (97) µm wide. Oesophagus short 20–61 (40.5). Intestine present as cyclocoel, bifurcation anterodorsal to ventral sucker, caecum proceeds in a loop lateroanteriorly from central oesophagus to level of pharynx, then 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, rounded, deeply lobed, symmetrical not contiguous; left testis surface area 9,824–67,443 (28,537) µm2; right testis surface area 11,496–55,941 (26,809) µm2. Seminal vesicle distinctly bipartite, composed of enclosed and extracaecal portions; enclosed portion 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 medially 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 4,351–41,853 (13,885) µm2; oviduct passes medio-posteriorly from ovary. Uterine seminal receptacle present. Laurer’s canal unites with oviduct posterior to ovary, passes and joins vitelline reservoir further posteriorly, passes posteriorly to open 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 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 into anterior portion of body, present in median portion of anterior part of body, but not dense, forming one – two loose rows; enclosed follicles in two masses, one mass in each lateral portion of enclosed area, sometimes scattered in interrupted band along inner posterior margin of cyclocoel, follicle number 22–54 (35). Vitelline reservoir immediately anterior to left testis. Eggs tanned, no operculum observed, unembryonated in utero, few, 2–19 (7) 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, dextro-laterally directed anterior to posterior loop of cyclocoel.

Molecular data: Sequence data were obtained from the 28S region from four host species - P. trifasciatus , P. ciliatus , P. indicus and P. multifasciatus ; from the ITS1 region from three host species – P. barberinus P. ciliatus , and P. multifasciatus and from the ITS2 region from 17 specimens from six host species - P. barberinus (4), P. trifasciatus (3), P. ciliatus (2), P. cyclostomus (1), P. indicus (1) and P. multifasciatus (6) ( Table 2 ).

Remarks: Specimens of T. chevrarum n. sp. are readily distinguished from T. haasi by their overall size and shape and the absence of a clear loop in the path of the ejaculatory duct. Transversotrema chevrarum n. sp. also has a short oesophagus unlike the long winding oesophagus of T. haasi . Further molecular (below) and morphological evidence show that T. chevrarum n. sp. from mullid fishes from Lizard Island is not conspecific with T. elegans , T. gigantica or T. lacerta (Hunter et al. 2010) . Although the vitelline follicles of T. chevrarum n. sp. extend into the anterior part of the body, they are scant compared with the specimens which the vitelline follicles are dense anteriorly. However, although T. lacerta also has fewer vitelline follicles in the anterior margin, molecular data separates that species quite clearly from T. chevrarum . Transversotrema chevrarum n. sp. is also distinguished from species within the complex of species related to T. licinum Manter, 1970 ( Hunter & Cribb 2012) by the D–shaped body outline and short oesophagus.

Transversotrema chevrarum n. sp. resembles T. cabrarum n. sp. closely but can be separated by a combination of features. The surface area of the left and right testes of T. chevrarum n. sp. average 28,537 µm2 and 26,809 µm2 respectively which is much smaller than those in T. cabrarum n. sp. which average 43,204 µm2 and 43,842 µm2 and the average ovary surface area (13,885 µm2) is also smaller in T. chevrarum n. sp. than that of T. cabrarum n. sp. (16,208 µm2). The follicles in the anterior margin of T. chevrarum n. sp. form a single row in the left anterior margin whereas the follicles in this region of T. cabrarum n. sp. form two rows and three rows in the right margin. Transversotrema chevrarum n. sp. is D–shaped in outline whereas T. cabrarum n. sp. is more lancet shaped. Separation of these species is considered further in statistical analysis below. Finally, molecular data (see below) distinguish T. chevrarum n. sp. from T. cabrarum n. sp. all the species characterised by Hunter et al. (2010) and Hunter & Cribb (2012).

Figures

FIGURE 2. Transversotrema chevrarum n. sp. ex Parupeneus ciliatus Lizard Island GBR, ventral. Holotype. Scale = 500 µm.

Tables

TABLE 4. Prevalence of transversotrematid species from mullid fishes from Lizard Island. (n = number of host fishes examined at this location; other numbers represent the species for which there is morphological and / or molecular data). Some individual fish harboured two species and only P. ciliatus harboured all three species found at L. I.

Host species	n T. chevrarum .	T. tragorum	T. sp.E	Mean richness
Mulloidichthys flavolineatus	6 0	0	1	0.17
Mulloidichthys vanicolensis	3 0	0	2	0.67
Parupeneus barberinus	21 1	3	0	0.19
Parupeneus ciliatus	12 2	1	2	0.42.
Parupeneus cyclostomus	6 1	3	0	0.67
Parupeneus indicus	10 1	4	0	0.5
Parupeneus multifasciatus	15 7	5	0	0.8
Parupeneus spilurus	2 0	0	0	0
Parupeneus trifasciatus	8 3	1	0	0.5