Diane P. Barton

Ecology of helminth communities in tropical Australian amphibians

Less than 50% of Australian amphibians have been recorded as hosts for helminth parasites. Despite developments in parasite community ecology in amphibians elsewhere, Australia lags behind with only two publications on this subject. Reasons advanced for this are that much of the collecting and taxonomic studies were conducted earlier this century before more recent discoveries of host genera and species as well as species complexes in the amphibian fauna. Consequently, there is a need for re-collection of hosts and parasites, and taxonomic revision of the parasites. In addition, as shown in this study, the parasite fauna in Australian amphibians is depauperate. Composition of the parasite fauna was largely dependent on the ecological associations of the host animal species. Frogs were infected with few helminth species and these occurred at low intensity, indicating, as in Europe and North America, that a depauperate fauna is also characteristic of amphibians in tropical regions.

Correlating Early Evolution of Parasitic Platyhelminths to Gondwana Breakup

Investigating patterns and processes of parasite diversification over ancient geological periods should involve comparisons of host and parasite phylogenies in a biogeographic context. It has been shown previously that the geographical distribution of host-specific parasites of sarcopterygians was guided, from Palaeozoic to Cainozoic times, mostly by evolution and diversification of their freshwater hosts. Here, we propose phylogenies of neobatrachian frogs and their specific parasites (Platyhelminthes, Monogenea) to investigate coevolutionary processes and historical biogeography of polystomes and further discuss all the possible assumptions that may account for the early evolution of these parasites. Phylogenetic analyses of concatenated rRNA nuclear genes (18S and partial 28S) supplemented by cophylogenetic and biogeographic vicariance analyses reveal four main parasite lineages that can be ascribed to centers of diversity, namely Australia, India, Africa, and South America. In addition, the relationships among these biogeographical monophyletic groups, substantiated by molecular dating, reflect sequential origins during the breakup of Gondwana. The Australian polystome lineage may have been isolated during the first stages of the breakup, whereas the Indian lineage would have arisen after the complete separation of western and eastern Gondwanan components. Next, polystomes would have codiverged with hyloid sensu stricto and ranoid frog lineages before the completion of South American and African plate separation. Ultimately, they would have undergone an extensive diversification in South America when their ancestral host families diversified. Therefore, the presence of polystome parasites in specific anuran host clades and in discrete geographic areas reveals the importance of biogeographic vicariance in diversification processes and supports the occurrence and radiation of amphibians over ancient and recent geological periods.

Raillietiella indica (Pentastomida) from the Lungs of the Giant Toad, Bufo marinus (Amphibia), in Hawaii, U.S.A

Abstract The pentastome Raillietiella indica was collected from the introduced toad Bufo marinus in Oahu, Hawaii, U.S.A. The parasite was identified as R. indica from similarities in morphology of the hooks, buccal cadre, and male copulatory spicule. This represents a new host record for this parasite, previously only recorded from Bufo melanostictus. This also represents a new locality record because this parasite has only been reported previously in India, Burma, and Taiwan. This is the third record of B. marinus as a host for parasites in Hawaii.

Pentastomid Parasites of the Introduced Asian House Gecko, Hemidactylus frenatus (Gekkonidae), in Australia

Abstract Hemidactylus frenatus is reported as a host for the pentastome parasites Raillietiella frenatus and Waddycephalus sp. in Australia for the first time. Both adult and nymphal pentastomes were found to infect H. frenatus collected in the Northern Territory and surrounding islands but were absent in North Queensland. Raillietiella frenatus, reported from H. frenatus throughout Southeast Asia and the Pacific Islands, is also reported in Australia for the first time. A single specimen of a female Raillietiella sp., corresponding to the measurements for R. frenatus, is reported from the native gecko Gehyra australis. Raillietiella frenatus has been reported transferring between host species in other locations where H. frenatus has been introduced. The need for further study of the pentastome parasites of geckoes in northern Australia to determine the spread of R. frenatus is emphasized.

Two gonad-infecting species of Philometra (Nematoda: Philometridae) from marine fishes off the northern coast of Australia

Two different gonad-infecting species of Philometra Costa, 1845 were collected from the ovary of marine perciform fishes, the blackspotted croaker Protonibea diacanthus (Sciaenidae) and the John’s snapper Lutjanus johnii (Lutjanidae), from off the northern coast of Australia. Nematodes (males and females) from P. diacanthus represent a new taxon, Philometra protonibeae n. sp., which is mainly characterized by the body length of the males (3.37–3. 90 mm), broad, equally long spicules (length 126–141 μm) and the shape and structure of the gubernaculum with a dorsally lamellate distal tip. The nematodes (only females) from L. johnii may represent an undescribed species, but, because of the absence of conspecific males, they could not be specifically identified. Philometra protonibeae is the fifth nominal gonad-infecting species of this genus recorded from marine fishes in Australian waters and the seventh species of these parasites described from fishes of the family Sciaenidae.

Helminth infracommunities in Litoria genimaculata (Amphibia: Anura) from Birthday Creek, an upland rainforest stream in northern Queensland, Australia

The helminth fauna of Litoria genimaculata, a rainforest frog from northern Queensland, was quantified from 53 adult male frogs collected at monthly intervals between April 1990 and March 1991. The helminth fauna of this species was depauperate (6 species: Mesocoelium sp., Parapolystoma bulliense, Austraplectana sp., Onchocercidae gen. sp., Cosmocerca sp. and an unidentified nematode larva). The most commonly encountered species was P. bulliense, but the intestinal infracommunity was dominated by the digenean Mesocoelium sp. Fifty-five per cent of frogs were infected with only 1 helminth species and only 1 frog had more than 2 species, resulting in low diversity values. These results support previous studies which indicate that amphibians have depauperate helminth communities.

Zeylanurotrema-spearei Sp-N (Digenea, Brachylaimidae) from the cane toad, Bufo-marinus, in Australia

Zeylanurotrema spearei sp.n. is described from the urinary bladder of the introduced cane toad, Bufo marinus, from North Queensland, Australia. The other species in Zeylanurotrema, Z.lyriocephali, has been recorded only from an agamid lizard from Sri Lanka. The new species has differently arranged gut caeca, vitelline follicles and ovary as compared with Z. lyriocephali. Z. spearei has a Laurers canal that does not open to the exterior but which forms a glandular Juels organ. We suggest that Z. spearei is an Australian species that has been acquired by the cane toad from a native host. In juvenile specimens of Z. spearei a persistent microcercous tail is present. From this and the anatomy of the adult we conclude that Zeylanurotrema is a brachylaimid rather than a urotrcmatid as originally proposed. A new subfamily, the Zeylanurotrematinae, is proposed to accommodate Zeylanurotrema.

Polyopisthocotylean monogeneans from carangid fishes off Queensland, Australia and New Caledonia, with a description of Heteromicrocotyloides megaspinosus sp. nov.

Gills of carangid fishes in Australian waters are dominated by a diversity of polyopisthocotylean monogeneans. This study updates current knowledge of polyopisthocotyleans from carangid hosts in waters along the Queensland coast of Australia and also off New Caledonia. The discovery of Protomicrocotyle celebesensis Yamaguti, 1953 is the first record for the genus in Australian waters and represents a new geographic location for the species, extending its distribution from Sulawesi, Indonesia and Hawaii to Australia. Furthermore, Caranx ignobilis and Carangoides fulvoguttatus are reported as new host records for P. celebesensis. Carangoides gymnostethus is recorded as a new host for Heteromicrocotyla australiensis Rohde, 1977 from a new geographic location, namely Lizard Island, Queensland. Heteromicrocotyloides mirabilis Rohde, 1977 is reported from the gills of C. fulvoguttatus off Lizard Island, Queensland representing a new geographic record. Heteromicrocotyloides megaspinosus sp. nov. is described from the gills of C. fulvoguttatus from Lizard Island, Queensland and New Caledonia. The new species is distinguished from H. mirabilis by the larger number and size of spines in the male genital corona. Gonoplasius carangis was collected from Pseudocaranx dentex at Heron Island, Queensland. Gonoplasius longirostri is synonymised with G. carangis due to overlap in measurements and similar morphology. The number of ‘dorsal pits’ in this taxon may not be a useful character because they can be cryptic and hard to see. Most hosts from which these two Gonoplasius species have been collected previously have been synonymised as Pseudocaranx dentex except Caranx ascensionis which is now considered to be C. lugubris. Our report of G. carangis from P. dentex at Heron Island, Queensland is a new geographic record.RésuméLes branchies des poissons Carangidae des eaux Australiennes sont dominées par une variété de monogènes Polyopisthocotylea. Cette étude met à jour notre connaissance actuelle des Polyopisthocotylea des Carangidae des eaux des côtes du Queensland (Australie) et aussi de Nouvelle-Calédonie. La découverte de Protomicrocotyle celebesensis Yamaguti, 1953 est la première mention du genre dans les eaux Australiennes et représente une nouvelle mention géographique pour l’espèce, étendant sa distribution depuis le Sulawesi, l’Indonésie et Hawaii jusqu’à l’Australie. De plus, Caranx ignobilis et Carangoides fulvoguttatus sont rapportés comme nouveaux hôtes pour P. celebesensis. Carangoides gymnostethus est rapporté comme nouvel hôte pour Heteromicrocotyla australiensis Rohde, 1977, d’une nouvelle localité géographique, Lizard Island, Queensland. Heteromicrocotyloides mirabilis Rohde, 1977 est rapporté des branchies de C. fulvoguttatus de Lizard Island, Queensland, comme nouvelle mention géographique. Heteromicrocotyloides megaspinosus sp. nov. est décrit des branchies de C. fulvoguttatus de Lizard Island, Queensland et de Nouvelle-Calédonie. La nouvelle espèce est distinguée de H. mirabilis par des épines plus nombreuses et plus longues dans la couronne génitale. Gonoplasius carangis a été collecté de Pseudocaranx dentex à Heron Island, Queensland. Gonoplasius longirostri est synonymisé avec G. carangis sur la base de recouvrements des mensurations et d’une morphologie similaire. Le nombre de “puits dorsaux” dans ce taxon n’est probablement pas un caractère utile car ces structures peuvent être cryptiques et difficiles à voir. La plupart des hôtes chez lesquels ces deux espèces de Gonoplasius ont été précédemment collectées ont été synonymisés avec Pseudocaranx dentex, à part Caranx ascensionis qui est maintenant considéré comme étant C. lugubris. Notre mention de G. carangis chez P. dentex à Heron Island, Queensland, est une nouvelle mention géographique.

Three species of the genus Dolichosaccus Johnston, 1912 (Digenea: Telorchiidae) from the introduced toad Bufo marinus (Amphibia: Bufonidae) in Australia, with the erection of Meditypus n. subg.

Members of the genus Dolichosaccus are recorded from the introduced cane toad in Australia for the first time. Redescriptions of the species D. symmetrus (Johnston, 1912) Yamaguti, 1958 and D. juvenilis (Johnston, 1912) Travassos, 1930 are provided and a new species, D. helocirrus n. sp., is described. Litoria caerulea is also recorded as a host for D. helocirrus n. sp. A new subgenus, Meditypus, is erected to accommodate D. juvenilis, D. grandiacetabularis Moravec & Sey, 1989, D. longibursatus Moravec & Sey, 1989 and D. helocirrus n. sp. D. schmidti Fischthal & Kuntz, 1975 is transferred from the subgenus Dolichosaccus to the subgenus Lecithopyge on the basis of the extent of the uterus. A key to the subgenera is provided.

Strong population structure deduced from genetics, otolith chemistry and parasite abundances explains vulnerability to localized fishery collapse in a large Sciaenid fish, Protonibea diacanthus

As pressure on coastal marine resources is increasing globally, the need to quantitatively assess vulnerable fish stocks is crucial in order to avoid the ecological consequences of stock depletions. Species of Sciaenidae (croakers, drums) are important components of tropical and temperate fisheries and are especially vulnerable to exploitation. The black‐spotted croaker, Protonibea diacanthus, is the only large sciaenid in coastal waters of northern Australia where it is targeted by commercial, recreational and indigenous fishers due to its food value and predictable aggregating behaviour. Localized declines in the abundance of this species have been observed, highlighting the urgent requirement by managers for information on fine‐ and broad‐scale population connectivity. This study examined the population structure of P. diacanthus across north‐western Australia using three complementary methods: genetic variation in microsatellite markers, otolith elemental composition and parasite assemblage composition. The genetic analyses demonstrated that there were at least five genetically distinct populations across the study region, with gene flow most likely restricted by inshore biogeographic barriers such as the Dampier Peninsula. The otolith chemistry and parasite analyses also revealed strong spatial variation among locations within broad‐scale regions, suggesting fine‐scale location fidelity within the lifetimes of individual fish. The complementarity of the three techniques elucidated patterns of connectivity over a range of spatial and temporal scales. We conclude that fisheries stock assessments and management are required at fine scales (100 s of km) to account for the restricted exchange among populations (stocks) and to prevent localized extirpations of this species. Realistic management arrangements may involve the successive closure and opening of fishing areas to reduce fishing pressure.