Stephanostomum spp. (Digenea: Acanthocolpidae) from scombrids and carangids (Perciformes) from the Great Barrier Reef, with the description of two new species

 

Stephanostomum spp. (Digenea: Acanthocolpidae) de escómbridos y carángidos (Perciformes) del arrecife de la Gran Barrera, con descripción de dos especies nuevas

 

Rodney A. Bray^1* and Thomas H. Cribb²

 

¹Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK.

²Centre for Marine Studies and Department of Microbiology and Parasitology, The University of Queensland, Brisbane, Queensland 4074, Australia.

 

*Correspondent:
rab@nhm.ac.uk

 

Recibido: 09 octubre 2007
Aceptado: 19 febrero 2008

 

Abstract

Two new species and 4 Stephanostomum spp. as new host and/or locality records from Percifomes from the Great Barrier Reef are described: Stephanostomum lamothei n. sp. from Grammatorcynus bilineatus (type–host) and G. bicarinatus, Lizard Island and Swain Reefs, is characterised by its 50–55 circum–oral spines and >than 20% of the hindbody length lacking vitelline follicles; Stephanostomum Tupatupa n. sp. from Caranx papuensis, Lizard Island, is characterised by its 34–36 circum–oral spines and <8% of the hindbody length lacking vitelline follicles; Stephanostomum ditrematis (Yamaguti, 1939) is reported from Gnathanodon speciosus, Heron Island and Lizard Island; Stephanostomum hawaiiense Yamaguti, 1970 and Stephanostomum carangi Liu, 1998 are reported from Carangoides fulvoguttatus, Lizard Island; Stephanostomum nyoomwa Bray and Cribb, 2003 is reported from Caranx sexfasciatus, Lizard Island.

Key words: Digenea, Acanthocolpidae, Stephanostomum, Great Barrier Reef, Carangidae, Scombridae.

 

Resumen

Se describen 2 especies nuevas del género Stephanostomum y se redescriben 4 más parásitas de perciformes del arrecife de la Gran Barrera australiana. Stephanostomum lamothei n. sp., parásito de Grammatorcynus bilineatus (hospedero–tipo) y de G. bicarinatus, de la isla Lizard y de los arrecifes Swain, se caracteriza por sus 50–55 espinas circumorales y por carecer de folículos vitelinos en más del 20% de la longitud del cuerpo; Stephanostomum Tupatupa n. sp. de Caranx papuensis de la isla Lizard, exhibe como rasgos diagnósticos 34–36 espinas circumorales y folículos vitelinos en menos del 8% de la longitud del cuerpo; Stephanostomum ditrematis (Yamaguti, 1939) se registra en Gnathanodon speciosus de las islas Heron y Lizard; Stephanostomum hawaiiense Yamaguti, 1970 y Stephanostomum carangi Liu, 1998 se recolectaron en Carangoides fulvoguttatus y finalmente, Stephanostomum nyoomwa Bray and Cribb, 2003 se encontró parasitando a Caranx sexfasciatus, ambos peces de la isla Lizard.

Palabras clave: Digenea, Acanthocolpidae, Stephanostomum, arrecife de la Gran Barrera, Carangidae, Scombridae.

 

Introduction

This is a further report on our studies of the members of the large genus Stephanostomum Looss, 1899, documenting species found in the waters of the Great Barrier Reef (Bray and Cribb, 2003; Bray and Cribb, 2004; Bray and Cribb, 2006; Bray et al., 2007). A large proportion of Stephanostomum Looss, 1899 species are reported in fishes of the family Carangidae and all but 1 of the species described here are from fishes of that family, the other, a new species, being from scombrids.

 

Materials and methods

Digeneans collected from freshly killed fish were fixed by being pipetted into nearly boiling saline and immediately preserved in formalin or 70% ethanol. Whole–mounts were stained with Mayer's paracarmine, cleared in beechwood creosote and mounted in Canada balsam. Measurements were made through a drawing tube on an Olympus BH–2 microscope, using a Digicad Plus digitising tablet and Carl Zeiss KS100 software adapted by Imaging Associates, and are quoted in micrometres, with the range and the mean in parentheses (Table 1). The following abbreviations are used: BMNH, the British Museum (Natural History) Collection at the Natural History Museum, London, UK; QM, Queensland Museum Collection, Brisbane, Australia.

 

Descriptions

Family Acanthocolpidae Lühe, 1906

Genus Stephanostomum Looss, 1899

Stephanostomum lamothei n. sp. (Figs. 1–6)

Based on 18 whole–mount preparations from Grammatorcynus bilineatus and 24 from G. bicarinatus, 5 of which were from the Swain Reefs. Measurements and ratios in Table 1. Measurements are based on the relatively small number of specimens which we were able to mount dorso–ventrally, due to the ventral flexing of the forebody on fixation. Body elongate, narrow, widest in region of ventral sucker or testes (Figs. 1, 4). Tegument spinous, unarmed patch immediately posterior to oral sucker, spines small, scale–like and densely packed in forebody, smaller in hindbody, becoming sparse in hindbody, detectable to varying levels in hindbody, in some cases to posterior extremity. Oral sucker terminal, distinctly wider than long. Circum–oral spines in double ring, without ventral hiatus; spines frequently distorted, reduced to very small size or lost, counts only on clearly normal sets of spines (Figs. 2, 5). Ventral sucker oval, in anterior fifth of body. Prepharynx long. Pharynx pyriform. Oesophagus short. Intestinal bifurcation in posterior forebody. Caeca long, narrow, form uroproct.

Testes 2, oval, entire, tandem, contiguous. Post–testicular region short or very short, usually relatively shorter in worms from G. bicarinatus. Cirrus–sac elongate (Figs. 3, 6), reaches well into hindbody; anterior extremity in anterior hindbody or overlapping to about mid–ventral sucker. Seminal vesicle saccular, oval, undivided. Pars prostatica short, narrower distally, lined with anuclear cell–like bodies, surrounded by gland–cells. Ejaculatory duct long, wide, lined with closely packed small cupolas, with round bases seen as circles on wall of duct, with distinct naked region distally. Genital atrium long, reaching to mid–ventral sucker or just into hindbody. Genital pore median, slit–like, immediately anterior to ventral sucker.

Ovary oval, entire, usually slightly separated from anterior testis, occasionally contiguous. Mehlis' gland antero–dorsal to ovary. Laurer's canal opens dorsally to ovary. Uterine seminal receptacle in proximal uterus. Uterus narrow, intercaecal, pre–ovarian. Eggs large, tanned operculate. Metraterm slightly shorter than cirrus–sac, lining similar to ejaculatory duct. Vitellarium follicular, just overlaps posterior end of cirrus–sac; fields confluent or nearly so ventrally and dorsally to uterus, lateral to and slightly overlap gonads, confluent or nearly so dorsally and ventrally in post–testicular region.

Excretory pore terminal. Vesicle I–shaped, reaches to mid–level of anterior testis.

Taxonomic summary

Type–host: Grammatorcynus bilineatus (Rüppell, 1836), Scombridae, double–lined mackerel.

Other host: Grammatorcynus bicarinatus (Quoy and Gaimard, 1825), Scombridae; shark mackerel.

Site of infection: intestine.

Type–locality: Lizard Island, Australia. (14°40'S, 145°28'E, Aug., 2002, May, June, 2005, April 2006).

Other locality: Swain Reefs (21°53'S, 152°21'E, Feb. 2001).

Prevalence and intensity: G. bilineatus, Lizard Island 75% (3 of 4), 6–10; G. bicarinatus, Lizard Island, 39% (9 of 23), 1–13; Swain Reefs, 100% (1 of 1), 5.

Deposition of specimens: G. bilineatus, Lizard Island, holotype QM G223080, paratypes QM G223081–223092, BMNH 2007.11.14.17–22; G. bicarinatus, Lizard Island, paratypes QM G223093–223101, BMNH 2007.11.14.3–16; Swain Reefs, paratypes QM G223102–223104, BMNH 2007.11.14.1–2.

Etymology: the species is named after Dr. Rafael Lamothe Argumedo, the laureate of this volume in recognition of his great contribution to fish parasitology.

Remarks

According to the list of species of Stephanostomum in Bray and Cribb (2003), only 2 species have the vitellarium separated from the ventral sucker by an extent greater than 10% of the hindbody length and about 50 to 52 circum–oral spines. A further 1 has been added since. S. lamothei is distinguished from these species as follows.

Stephanostomum caducum (Looss, 1901), mainly from gadids in the Mediterranean and the north–eastern Atlantic, has 48–50 circum–oral spines, widely spaced gonads with intervening vitelline follicles and gaps in the vitellarium lateral to the gonads (Looss, 1901; Nicoll, 1914; Srivastava, 1966; Køie, 1978).

Stephanostomum lineatum Manter, 1934 from gadids and morids off Florida and Argentina, has 50–52 circum–oral spines in 3 rows (rather than 2 as found in S. lamothei), widely spaced gonads with intervening vitelline follicles and gaps in the vitellarium lateral to the gonads (Manter, 1934; Szidat, 1961).

Stephanostomum euzeti Bartoli and Bray, 2004, found as an adult in the carangid Seriola dumerili (Risso) (Carangidae) and as a metacercaria in the bogue Boops boops (Linnaeus, 1758) (Sparidae) from the western Mediterranean, has 49–51 circum–oral spines, a wide funnel–shaped oral sucker, a relatively much longer forebody (20–35% of body length) and a relatively shorter ovary to ventral sucker distance (about 31–42% of body–length) (Bartoli and Bray, 2004; Pérez–del Olmo et al., 2007).

Stephanostomum Tupatupa n. sp. (Figs. 7–9)

Based on 5 whole–mount preparations. Measurements and ratios in Table 1. Body elongate, narrow, widest in region of ventral sucker or testes (Fig. 7). Tegument spinous, unarmed patch immediately posterior to oral sucker, spines acuminate with wide base, densely packed in forebody, smaller in hindbody, becoming sparse in hindbody, detectable only to well anterior to ovary. Oral sucker more or less terminal, antero–posteriorly narrow. Circum–oral spines in double ring, without ventral hiatus (Fig. 8). Ventral sucker rounded. Forebody long. Prepharynx long. Pharynx elongate oval. Oesophagus long. Intestinal bifurcation in posterior forebody. Caeca long, narrow, form uroproct.

Testes 2, oval, entire, tandem, contiguous. Post–testicular region short. Cirrus–sac relatively short (Fig. 9), anterior extremity dorsal to ventral sucker. Seminal vesicle saccular, oval, undivided. Pars prostatica separated from seminal receptacle by clear sphincter, relatively short, wider proximally, lined with anuclear cell–like bodies, surrounded by gland–cells; narrows distally to form relatively thick–walled duct. Ejaculatory duct relatively short, wide, lined with closely packed distinct cupolas, with round bases seen as circles on wall of duct, with distinct naked region distally. Genital atrium short, reaching dorsally to ventral sucker. Genital pore median, slit–like, immediately anterior to ventral sucker.

Ovary oval to round, entire, contiguous or very close to anterior testis. Mehlis' gland antero–dorsal to ovary. Laurer's canal opens dorsally to ovary. Uterine seminal receptacle in proximal uterus. Uterus narrow, intercaecal, pre–ovarian. Eggs large, tanned operculate. Metraterm of similar length to cirrus–sac, unnarmed. Vitellarium follicular, just overlapping or reaching posterior end of cirrus–sac; fields confluent or nearly so ventrally and dorsally to uterus, lateral to and overlap gonads, no follicles between gonads, confluent dorsally and ventrally in post–testicular region.

Excretory pore terminal. Vesicle I–shaped, reaches to posterior testis.

Taxonomic summary

Type–host: Caranx papuensis Alleyne and Macleay, 1877, Carangidae, brassy trevally.

Site of infection: intestine.

Type–locality: Lizard Island (14°40'S, 145°28'E, June 2005).

Prevalence and intensity: 6.25% (1 of 16), 7.

Deposition of specimens: holotype QM G 223115, paratypes QM G 223116–23318, BMNH 2007.11.14.23–24.

Etymology: Tupatupa is a Papuan vernacular name for the host.

Remarks

Stephanostomum Tupatupa n. sp. fits comfortably into the Bray and Cribb's (2003) group one with the vitellarium distance from the ventral sucker less than 10% of the hindbody length. They list 5 species with circum–oral spines rows of about 36. S. Tupatupa differs from these thus: Stephanostomum cesticillum (Molin, 1858), reported mainly from the angler Lophius piscatorius Linnaeus, 1758 (Lophiidae) from the Mediterranean and Atlantic Ocean, is the type–species of the genus, has separated testes with intervening vitelline follicles, a sucker ratio of 1:43–1.99, a ventral hiatus in the circum–oral suckers, blind–caeca, a long cirrus–sac, with a long ejaculatory duct armed with occasional small spines, not obvious in fixed specimens (Bartoli and Bray, 2001). Molecular results indicate that the records of this species from the John dory Zeus faber Linnaeus, 1758 (Zeidae) are valid (Bray et al., 2005), but records from other hosts need confirmation.

Stephanostomum carangi Liu, 1998 from the giant trevally Caranx ignobilis (Forsskål, 1775) (Carangidae) of Dongshan Island, China, is a broader worm (width about 18–23% of body–length), a funnel–shaped oral sucker, a relatively shorter forebody (about 24% of body–length) and ventral sucker to ovary distance (about 20% of body–length). The terminal genitalia are not well enough described for a meaningful comparison (Liu, 1998).

Stephanostomum coryphaenae Manter, 1947, reported mainly from the common dolphinfish Coryphaena hippurus Linnaeus, 1758 (Coryphaenidae) from the northern tropical Atlantic, is a broader worm (width about 13–22% of body–length), with a sucker ratio 1:1.4–1.8, a short forebody (about 15–18% of body–length) and longer post–testicular region (about 19% of body–length). The testes are said to be separated by a few vitelline follicles (Manter, 1947; Siddiqi and Cable, 1960; Travassos et al., 1967).

Stephanostomum simhai Gupta and Ahmad, 1979 from the goldlined seabream Rhabdosargus sarba (Forsskål, 1775) (Sparidae) in the Bay of Bengal, is said to have separate ani, and has a short forebody (about 24% of body–length) and long post–testicular region (about 20% of body–length). The terminal genitalia are not well enough described for a meaningful comparison (Gupta and Ahmad, 1979).

Stephanostomum trompeteri Zhukov, 1983, from the cornet fish Fistularia tabacaria Linnaeus, 1758 (Fistulariidae) in the southern Gulf of Mexico (Zhukov, 1983). The illustration is of a twisted worm, but it appears that the forebody is short (about 20% of body–length) and that there is no significant oesophagus. The terminal genitalia are described perfunctorily in this Atlantic species.

Stephanostomum ditrematis (Yamaguti, 1939) Manter, 1947. (Figs. 10–12)

Syns. Echinostephanus ditrematis Yamaguti, 1939; Stephanostomum seriolae Yamaguti, 1970.

Based on 9 whole–mount preparations. Measurements and ratios in Table 1. Body elongate, narrow, widest in region of ventral sucker or testes (Fig. 10). Tegument spinous, unarmed patch immediately posterior to oral sucker, spines acuminate with wide base, densely packed in forebody, smaller in hindbody, becoming sparse in hindbody, detectable to just anterior to ovary. Oral sucker more or less terminal, subglobular. Circum–oral spines in double ring, without ventral hiatus; posterior ventral spines smaller than remainder (Fig. 11). Ventral sucker rounded, in anterior fifth of body. Prepharynx long. Pharynx elongate. Oesophagus short. Intestinal bifurcation in posterior forebody or at about anterior margin of ventral sucker. Caeca long, narrow, form uroproct.

Testes 2, oval, entire, tandem, separated. Post–testicular region very short. Cirrus–sac elongate (Fig. 12), entirely within hindbody; anterior extremity well posterior to ventral sucker. Seminal vesicle saccular, oval, undivided. Pars prostatica separated from seminal receptacle by clear sphincter, elongate, wider proximally, lined with anuclear cell–like bodies, surrounded by gland–cells; narrows distally to form relatively thick–walled duct. Ejaculatory duct long, wide, lined with closely packed distinct deep cupolas, showing distally directed chevron–like effect, with round bases seen as circles on wall of duct, with distinct naked region distally. Genital atrium very long, reaching well into hindbody. Genital pore median, slit–like, immediately anterior to ventral sucker.

Ovary oval to round, entire, separated from anterior testis. Mehlis' gland antero–dorsal to ovary. Laurer's canal opens dorsally to ovary. Uterine seminal receptacle in proximal uterus. Uterus narrow, intercaecal, pre–ovarian. Eggs large, tanned operculate. Metraterm of similar length to cirrus–sac, lining irregular, but not armed. Vitellarium follicular, just overlapping or reaching posterior end of cirrus–sac; fields confluent or nearly so ventrally and dorsally to uterus, lateral to and overlap gonads, confluent ventrally and dorsally between ovary and anterior testis and between testes, confluent dorsally and ventrally in post–testicular region.

Excretory pore terminal. Vesicle I–shaped, short, not traced past posterior testis.

Taxonomic summary

Host: Gnathanodon speciosus (Forsskål), Carangidae, golden trevally.

Site of infection: intestine.

Localities: Heron Island (23°27'S, 151°55'E, May, 2003); Lizard Island (14°40'S, 145°28'E, June 2005) (2 immature only).

Prevalence and intensity: Heron Island 25% (1 of 4), 7; Lizard Island 50% (2 of 4), 2–11.

Deposition of specimens: Heron Island, QM G223112–223114, BMNH 2007.11.14.25–29; Lizard Island, QM G223105–223111, BMNH 2007.11.14.30–33.

Remarks

Stephanostomum ditrematis (Yamaguti, 1939) is reported widely, mainly from carangids, and may constitute a composite species, but the type–specimens and the worms described by Bartoli and Bray (2004) from Seriola dumerili (Risso, 1810) (Carangidae) in the Mediterranean Sea off Corsica, are similar to those described here. It was reported from Gnathanodon speciosus by Parukhin (1970; 1976) from the Red Sea, Indian Ocean and the South China Sea. The cupolas lining the ejaculatory duct appear to be more prominent than those described by Bartoli and Bray (2004), where they were described as weakly developed, but the overall morphology is not sufficiently distinct to suggest that a separate species is present.

In all, 4 Stephanostomum species have been reported from Gnathanodon speciosus and the remaining 3 can readily be distinguished from S. ditrematis: Stephanostomum lebedevi Parukhin, 1974, which was reported by Parukhin (1976) from the Red Sea, has 46–48 circum–oral spines (Parukhin, 1974).

Stephanostomum megacephalum Manter, 1940, which was reported by Parukhin (1970; 1976) from the Red Sea and the Gulf of Mannar, is reported with 30–32 circum–oral spines, almost always 32 (Manter, 1940).

Stephanostomum talakitok Bray and Cribb, 2006, reported from Ningaloo Reef, Western Australia, has contiguous gonads with no intervening vitelline follicles, and a very short genital atrium (Bray and Cribb, 2006).

Stephanostomum hawaiiense Yamaguti, 1970. (Figs. 13–15)

Based on 5 whole–mount preparations. Measurements and ratios in Table 1. Body elongate, narrow, widest in region of ventral sucker or testes (Fig. 13). Tegument spinous, unarmed patch immediately posterior to oral sucker, spines acuminate with wide base, densely packed in forebody, smaller in hindbody, becoming sparse in hindbody, detectable to anterior testis. Oral sucker more or less terminal, weakly infundibuliform. Circum–oral spines in double ring, ventral hiatus (Fig. 14). Ventral sucker rounded. Forebody short. Prepharynx long. Pharynx elongate oval. Oesophagus short. Intestinal bifurcation in posterior forebody. Caeca long, form uroproct.

Testes 2, oval, entire, tandem, well separated. Post–testicular region short. Cirrus–sac relatively short (Fig. 15), anterior extremity well into hindbody. Seminal vesicle saccular, oval, undivided. Pars prostatica separated from seminal receptacle by clear sphincter, fairly long, slightly wider proximally, lined with anuclear cell–like bodies, surrounded by gland–cells, narrows distally. Ejaculatory duct of similar length to pars prostatica when withdrawn, wide, lined with closely packed distinct cupolas, with round bases seen as circles on wall of duct, with distinct naked region distally; in 1 specimen the ejaculatory duct is extruded through the genital pore as a cirrus; in another the ejaculatory duct is extruded within the genital atrium. Genital atrium long, reaching well into hindbody. Genital pore median, slit–like, immediately anterior to ventral sucker.

Ovary oval to round, entire, well separated from anterior testis. Mehlis' gland antero–dorsal to ovary. Laurer's canal opens dorsally to ovary. Uterine seminal receptacle in proximal uterus. Uterus narrow, intercaecal, pre–ovarian. Eggs large, tanned operculate. Metraterm of similar length to ejaculatory duct, unarmed. Vitellarium follicular, not quite reaching posterior end of cirrus–sac; fields confluent ventrally and dorsally to uterus, lateral to gonads, confluent between gonads, confluent dorsally and ventrally in post–testicular region.

Excretory pore terminal. Vesicle I–shaped, reaches to posterior testis.

Taxonomic summary

Host: Carangoides fulvoguttatus (Forsskål, 1775), Carangidae, yellowspotted trevally.

Site: intestine.

Locality: off Coconut beach and east of Lizard Island (14°40'S, 145°28'E, April 2006).

Prevalence and intensity: 14% (2 of 14), 2–3.

Deposition of specimens: QM G223119–223122, BMNH 2007.11.14.34–37.

Remarks

This species belongs to the group with >10% of the hindbody devoid of vitelline follicles as listed by Bray and Cribb (2003). Within that group it can be differentiated by the circum–oral spine number centred on 36 and a ventral hiatus in the spine rows. Three species exhibit this combination of characters, Stephanostomum hawaiiense Yamaguti, 1970, S. lateolabracis Liu, 1998 and S. manteri Vigueras, 1955.

We consider the present material practically indistinguishable from S. hawaiiense from the bigeye trevally Caranx sexfasciatus (Carangidae) from off Hawaii as described by Yamaguti (1970). The original description differs slightly from our interpretation in that we observe a uroproct, whereas Yamaguti did not. The uroproct is often obscured by vitelline follicles in this genus and we do not consider this point strong enough to consider the forms different. The armament of the ejaculatory duct was described as basally rounded spines, which we interpret to be the circular cupolas we observed.

It appears that S. lateolabracis from the Japanese seaperch Lateolabrax japonicus (Cuvier, 1828) (Lateolabracidae) off Dongshan Island, China, was incorrectly placed in this group (Group 2) of species by Bray and Cribb (2003) as it has <10% of the hindbody devoid of vitelline follicles; in fact the vitellarium reaches close to the ventral sucker (Liu, 1998). It should have been listed in Group 1. A ventral hiatus in the circum–oral spine rings is described, but is not clear in the illustration.

Stephanostomum manteri from the bar jack Carangoides ruber (Bloch, 1793) (Carangidae) off Cuba (Vigueras, 1955) has 36 circum–oral spines in the illustration, and a ventral hiatus is described. It apparently has a short genital atrium, not reaching into the hindbody.

Stephanostomum carangi Liu, 1998. (Figs. 16–18)

Based on 5 whole–mount preparations. Measurements and ratios in Table 1. Body elongate, narrow, widest in region of ventral sucker or testes (Fig. 16). Tegument spinous, unarmed patch immediately posterior to oral sucker, spines acuminate, densely packed in forebody, smaller in hindbody, becoming sparse in hindbody, detectable to level of ovary. Oral sucker more or less terminal, shallow infundibuliform. Circum–oral spines in double ring, without ventral hiatus (Fig. 17). Ventral sucker rounded. Forebody relatively long. Prepharynx long. Pharynx elongate oval. Oesophagus short. Intestinal bifurcation in posterior forebody. Caeca long, narrow, probably forms uroproct.

Testes 2, oval, entire, tandem, contiguous. Post–testicular region short. Cirrus–sac relative short (Fig. 18), anterior extremity dorsal to ventral sucker. Seminal vesicle saccular, oval, undivided. Pars prostatica separated from seminal receptacle by clear sphincter, short, lined with anuclear cell–like bodies, surrounded by gland–cells; narrows distally. Ejaculatory duct relatively long, wide, lined with closely packed distinct cupolas, with round bases seen as circles on wall of duct, with distinct naked region distally. Genital atrium very short, reaching dorsally to anterior part of ventral sucker. Genital pore median, slit–like, immediately anterior to ventral sucker.

Ovary oval to round, entire, contiguous or very close to anterior testis. Mehlis' gland antero–dorsal to ovary. Laurer's canal opens dorsally to ovary. Uterine seminal receptacle in proximal uterus. Uterus narrow, intercaecal, pre–ovarian. Eggs large, tanned operculate. Metraterm unnarmed, usually distended with eggs. Vitellarium follicular, overlapping cirrus–sac reaching close to ventral sucker; fields confluent or nearly so ventrally and dorsally to uterus, lateral to and overlap gonads, no follicles between gonads, confluent dorsally and ventrally in post–testicular region.

Excretory pore terminal. Vesicle I–shaped, reaches to posterior testis.

Taxonomic summary

Host: Carangoides fulvoguttatus (Forsskål, 1775), Carangidae, yellowspotted trevally.

Site of infection: intestine.

Locality: Lizard Island (14°40'S, 145°28'E, August 2002).

Prevalence and intensity: 14% (2 of 14), 1–2.

Deposition of specimens: QM G223123–223124, BMNH 2007.11.14.43.

Remarks

Four species of Stephanostomum were listed by Bray and Cribb (2003) as having less than 10% of the hindbody devoid of vitelline follicles, with a circum–oral spine number centred on 36 and without a ventral hiatus: S. carangi Liu, 1998, S. coryphaenae Manter, 1947, S. simhai Gupta and Ahmad, 1979 and S. trumpeteri Zhukov, 1983.

The present worms are practically indistinguishable from S. carangi from Caranx ignobilis (Carangidae) from off Dongshan Island, China (Liu, 1998) despite the fact that the original description, based on 2 specimens, appears to be based on flattened and distorted worms, as is indicated by the twisted appearance of the prepharynx and pharynx. This has also meant that the width ratio (about 18–23% of body–length) is much greater than found in our, unflattened specimens. The terminal genitalia are not described in detail, but the relatively short pars prostatica and long ejaculatory duct appear to be indicated.

Stephanostomum coryphaenae reported mainly from Coryphaena hippurus (Coryphaenidae) from the northern tropical Atlantic, has distinct gaps between the gonads, a short forebody (about 15–18% of body–length), a longer post–testicular region (about 19% of body–length) and a longer ovary to ventral sucker distance (about 35%). The testes are said to be separated by a few vitelline follicles (Manter, 1947; Siddiqi and Cable, 1960; Travassos et al., 1967).

Stephanostomum simhai Gupta and Ahmad, 1979 from the goldlined seabream Rhabdosargus sarba (Forsskål, 1775) (Sparidae) in the Bay of Bengal, is said to have separate ani, and has distinct gaps between the gonads, a short forebody (about 24% of body–length) and long post–testicular region (about 20% of body–length). The terminal genitalia are not well enough described for a meaningful comparison (Gupta and Ahmad, 1979).

Stephanostomum trompeteri Zhukov, 1983 is from the cornet fish Fistularia tabacaria Linnaeus, 1758 (Fistulariidae) in the southern Gulf of Mexico (Zhukov, 1983). The illustration is of a twisted worm, but it appears that the forebody is short (about 20% of body–length) and the ovary is slightly separated from the anterior testis. The terminal genitalia are described perfunctorily in this Atlantic species, but it appears that the genital atrium reaches to the posterior part of the ventral sucker.

Stephanostomum nyoomwa Bray and Cribb, 2003. (Figs. 19–21)

Taxonomic summary

Host: Caranx sexfasciatus Quoy and Gaimard, 1825, Carangidae, bigeye trevally.

Site of infection: intestine.

Locality: off Casuarina Beach, Lizard Island (14°40'S, 145°28'E, April 2006).

Prevalence and intensity: 50% (1 of 2), 10.

Deposition of specimens: QM G223125–G223129, BMNH 2007.11.14.38–42.

Remarks

The measurements are given in Table 1. This species was originally reported from Caranx sexfasciatus from Heron Island, in the southern Great Barrier Reef. The specimens from Lizard Island are indistinguishable from those described by Bray and Cribb (2003), apart from the sucker–width ratio (the ventral sucker is relatively smaller in the Lizard Island specimens) and the scattering of cupolas in the metraterm in some specimens.

 

Acknowledgements

We are grateful to Rob Adlard, Matt Nolan and Terry Miller for assistance with the collection. This study has been supported by the Australian Research Council, Australian Biological Resources Study and the Lizard and Heron Island Research Stations.

 

Literature cited

Bartoli, P. and R. A. Bray. 2001. Contribution to the knowledge of species of the genus Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from teleosts of the Western Mediterranean, with the description of S. gaidropsari n. sp. Systematic Parasitology 49:159–188.        [ Links ]

Bartoli, P. and R. A. Bray. 2004. Four species of Stephanostomum Looss, 1899 (Digenea, Acanthocolpidae) from Seriola dumerili (Risso) (Teleostei, Carangidae) in the Western Mediterranean, including S. euzeti n. sp. Systematic Parasitology 58:41–62.        [ Links ]

Bray, R. A. and T. H. Cribb. 2003. Species of Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from fishes of Australian and South Pacific waters, including five new species. Systematic Parasitology 55:159–197.        [ Links ]

Bray, R. A. and T. H. Cribb. 2004. Stephanostomum tantabiddii n. sp. (Digenea: Acanthocolpidae) from Carangoides fulvoguttatus (Forsskål, 1775) (Perciformes: Carangidae), from Ningaloo Reef, Western Australia. Zootaxa 457:1–8.        [ Links ]

Bray, R. A. and T. H. Cribb. 2006. Stephanostomum talakitok n. sp. (Digenea: Acanthocolpidae) from Gnathanodon speciosus (Perciformes: Carangidae) from Ningaloo Reef, Western Australia. Zootaxa 1104:59–68.        [ Links ]

Bray, R. A., T. H. Cribb, A. Waeschenbach and D. T. J. Littlewood. 2007. A new species of Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) with a bizarre oral sucker: S. adlardi n. sp. from the common coral trout Plectropomus leopardus (Lacepède, 1802) (Perciformes: Serranidae) from Lizard Island, Great Barrier Reef. Acta Parasitologica 52:206–212.        [ Links ]

Bray, R. A., B. L. Webster, P. Bartoli and D. T. J. Littlewood. 2005. Relationships within the Acanthocolpidae Lühe, 1906 and their place among the Digenea. Acta Parasitologica 50:281–291.        [ Links ]

Gupta, V. and J. Ahmad. 1979. Digenetic trematodes of marine fishes. On five new digenetic trematodes from marine fishes of Bay of Bengal, Puri, Orissa. Helminthologia 16:161–171.        [ Links ]

Køie, M. 1978. On the morphology and life–history of Stephanostomum caducum (Looss 1901) Manter 1934 (Trematoda, Acanthocolpidae). Ophelia 17:121–133.        [ Links ]

Liu S.–f. 1998. The trematodes of marine fishes from Fujian, China (Acantholpidae ( sic). Zoological Research 19:468–472. (In Chinese).        [ Links ]

Looss, A. 1901. Ueber die Fasciolidengenera Stephanochasmus, Acanthochasmus und einige andere. Centralblatt für Bakteriologie, Parasitenkunde und Infektionskrankheiten 29:595–606, 628–634, 654–661.        [ Links ]

Manter, H. W. 1934. Some digenetic trematodes from deep–water fish of Tortugas, Florida. Papers from Tortugas Laboratory 28:257–345.        [ Links ]

Manter, H. W. 1940. Digenetic trematodes of fishes from the Galapagos Islands and the neighboring Pacific. Allan Hancock Pacific Expeditions 2:325–497.        [ Links ]

Manter, H. W. 1947. The digenetic trematodes of marine fishes of Tortugas, Florida. American Midland Naturalist 38:257–416.        [ Links ]

Nicoll, W. 1914. The trematode parasites of fishes from the English Channel. Journal of the Marine Biological Association of the United Kingdom 10:466–505.        [ Links ]

Parukhin, A. M. 1970. (On the study of trematode fauna in fish from the Red Sea and Aden Bay). Biologiya Morya, Kiev 20:187–213. (In Russian).        [ Links ]

Parukhin, A. M. 1974. Some new trematode species of the family Acanthocolpidae Luhe, 1909 from fishes of the Red Sea and Indian Ocean. Izvestiya Tikhookeanskogo Nauchno–Issledovatel'skogo Instituta Rybnogo Khozyaistva i Okeanografii (TINRO) 88:110–116. (In Russian).        [ Links ]

Parukhin, A. M. 1976. (Parasitic worms of food fishes of the southern Seas). Kiev, Naukova Dumka. 183 p. (In Russian).        [ Links ]

Pérez–del Olmo, A., M. Fernández, D. I. Gibson, J. A. Raga and A. Kostadinova. 2007. Descriptions of some unusual digeneans from Boops boops L. (Sparidae) and a complete checklist of its metazoan parasites. Systematic Parasitology 66:137–157.        [ Links ]

Siddiqi, A. H. and R. M. Cable. 1960. Digenetic trematodes of marine fishes of Puerto Rico. Scientific Survey of Porto Rico and the Virgin Islands 17:257–369.        [ Links ]

Srivastava, L. P. 1966. A re–description of Stephanostomum caducum (Looss, 1901) (Digenea: Acanthocolpidae) from the intestine of Onos mustelus (L.). Annals and Magazine of Natural History 9:399–403.        [ Links ]

Szidat, L. 1961. Versuch einer Zoogeographie des Sud–Atlantik mit Hilfe von Zeitparasiten der Meeresfische. Parasitologische Schriftenreihe 13:1–98.        [ Links ]

Travassos, L., J. F. T. de Freitas and P. F. Bührnheim. 1967. Relatória da excursao do Instituto Oswaldo Cruz ao Éstado do Espírito Santo em Novembro de 1964. Boletím do Museu de Biologia Prof. Mello Leitâo (Zoologia) 31:1–54.        [ Links ]

Vigueras, I. P. 1955. Descripción de seis especies nuevas de trematodes de la familia Acanthocolpidae y división del género Stephanostomum en sub–géneros. Revista Ibérica de Parasitología, Tomo Extraordinario, Libro–homenaje al Prof. López–Neyra. p. 421–441.        [ Links ]

Yamaguti, S. 1970. Digenetic trematodes of Hawaiian fishes. , Keigaku, Tokyo. 436 p.        [ Links ]

Zhukov, E. V. 1983. New representatives of the fauna of trematodes from the fishes of the Gulf of Mexico. Parazitologiya 17:112–117. (In Russian).        [ Links ]