Siganidae

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Rebecca J. Fox - One of the best experts on this subject based on the ideXlab platform.

  • thermal sensitivity of juvenile rabbitfishes siganus doliatus and s lineatus Siganidae a key role for habitat
    Coral Reefs, 2021
    Co-Authors: Lauren E Lamonica, Rebecca J. Fox, Jennifer M Donelson
    Abstract:

    The majority of our understanding of the effects of climate change on coral reef fishes are currently based on studies of small-bodied species such as damselfishes. By contrast, we know little about the potential impacts of ocean warming on larger species of herbivorous and detritivorous reef fish, despite them being a critical functional group and an essential source of food protein for millions of people. In addition, we know little of the role of habitat in determining species’ thermal sensitivity and the legitimacy of extrapolating thermal performance across closely-related species from different habitat types. Here we test the effect of exposure to increased water temperature during juvenile development on key physiological and behavioral traits of two species of rabbitfish typically associated with different habitats: Siganus doliatus (reef-associated) and S. lineatus (estuarine). Wild-caught juveniles were reared for 14 weeks at temperatures representing present-day ambient conditions (28.0 °C), late-summer ambient conditions (30.0 °C), or those projected on reefs under future global warming scenarios (31.5 °C). We then measured the somatic (growth, condition, immune response) and behavioral (feeding rate, latency to feed and activity level) traits of individuals within each treatment to determine the sensitivity of each species to elevated water temperatures. Overall, both species showed comparatively robust levels of thermal tolerance, based on previously-documented responses of small-bodied reef fishes. However, two very different patterns emerged. The reef-associated S. doliatus showed a greater physiological response to temperature, with negative effects on hepatosomatic condition and immune function observed in individuals exposed to the 31.5 °C treatment. By contrast, there were no negative physiological effects of temperature observed in S. lineatus and instead we recorded behavioral changes, with individuals at 30 °C and 31.5 °C displaying altered feeding behavior (increased feeding rate and decreased latency to feed). These distinct responses observed between congeners are likely due to their evolutionary history and flag the potential inaccuracies that could arise from extrapolating effects of ocean warming across even closely-related species adapted to different habitats.

  • why pair evidence of aggregative mating in a socially monogamous marine fish siganus doliatus Siganidae
    Royal Society Open Science, 2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    Many species live in stable pairs, usually to breed and raise offspring together, but this cannot be assumed. Establishing whether pairing is based on mating, or an alternative cooperative advantage, can be difficult, especially where species show no obvious sexual dimorphism and where the act of reproduction itself is difficult to observe. In the tropical marine fishes known as rabbitfish (Siganidae), half of extant species live in socially monogamous, territorial pairs. It has been assumed that partnerships are for mating, but the reproductive mode of pairing rabbitfish is currently unconfirmed. Using passive acoustic telemetry to track movements of fishes belonging to one such species (Siganus doliatus), we provide the first evidence that paired adult fish undertake highly synchronized migrations with multiple conspecifics on a monthly cycle. All tagged individuals migrated along the same route in three consecutive months and were absent from home territories for 2–3 days just after the new moon. The timing and directionality of migrations suggest that S. doliatus may form spawning aggregations, offering the potential for exposure to multiple reproductive partners. The finding raises fundamental questions about the basis of pairing, mate choice and partnership longevity in this family.

  • Why pair? Evidence of
    2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    aggregative mating in a socially monogamous marine fish (Siganus doliatus, Siganidae). R. Soc. open sci. 2: 150252

David R. Bellwood - One of the best experts on this subject based on the ideXlab platform.

  • Coordinated vigilance provides evidence for direct reciprocity in coral reef fishes.
    Scientific reports, 2015
    Co-Authors: Simon J. Brandl, David R. Bellwood
    Abstract:

    Reciprocity is frequently assumed to require complex cognitive abilities. Therefore, it has been argued that reciprocity may be restricted to animals that can meet these demands. Here, we provide evidence for the potential presence of direct reciprocity in teleost fishes. We demonstrate that in pairs of coral reef rabbitfishes (f. Siganidae), one fish frequently assumes an upright vigilance position in the water column, while the partner forages in small crevices in the reef substratum. Both behaviours are strongly coordinated and partners regularly alternate their positions, resulting in a balanced distribution of foraging activity. Compared to solitary individuals, fishes in pairs exhibit longer vigilance bouts, suggesting that the help provided to the partner is costly. In turn, fishes in pairs take more consecutive bites and penetrate deeper into crevices than solitary individuals, suggesting that the safety provided by a vigilant partner may outweigh initial costs by increasing foraging efficiency. Thus, the described system appears to meet all of the requirements for direct reciprocity. We argue that the nature of rabbitfish pairs provides favourable conditions for the establishment of direct reciprocity, as continuous interaction with the same partner, simultaneous needs, interdependence, and communication relax the cognitive demands of reciprocal cooperation.

  • why pair evidence of aggregative mating in a socially monogamous marine fish siganus doliatus Siganidae
    Royal Society Open Science, 2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    Many species live in stable pairs, usually to breed and raise offspring together, but this cannot be assumed. Establishing whether pairing is based on mating, or an alternative cooperative advantage, can be difficult, especially where species show no obvious sexual dimorphism and where the act of reproduction itself is difficult to observe. In the tropical marine fishes known as rabbitfish (Siganidae), half of extant species live in socially monogamous, territorial pairs. It has been assumed that partnerships are for mating, but the reproductive mode of pairing rabbitfish is currently unconfirmed. Using passive acoustic telemetry to track movements of fishes belonging to one such species (Siganus doliatus), we provide the first evidence that paired adult fish undertake highly synchronized migrations with multiple conspecifics on a monthly cycle. All tagged individuals migrated along the same route in three consecutive months and were absent from home territories for 2–3 days just after the new moon. The timing and directionality of migrations suggest that S. doliatus may form spawning aggregations, offering the potential for exposure to multiple reproductive partners. The finding raises fundamental questions about the basis of pairing, mate choice and partnership longevity in this family.

  • Why pair? Evidence of
    2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    aggregative mating in a socially monogamous marine fish (Siganus doliatus, Siganidae). R. Soc. open sci. 2: 150252

  • diet and cross shelf distribution of rabbitfishes f Siganidae on the northern great barrier reef implications for ecosystem function
    Coral Reefs, 2013
    Co-Authors: Andrew S Hoey, Simon J. Brandl, David R. Bellwood
    Abstract:

    Herbivorous fishes are a critical functional group on coral reefs, and there is a clear need to understand the role and relative importance of individual species in reef processes. While numerous studies have quantified the roles of parrotfishes and surgeonfishes on coral reefs, the rabbitfishes (f. Siganidae) have been largely overlooked. Consequently, they are typically viewed as a uniform group of grazing or browsing fishes. Here, we quantify the diet and distribution of rabbitfish assemblages on six reefs spanning the continental shelf in the northern Great Barrier Reef. Our results revealed marked variation in the diet and distribution of rabbitfish species. Analysis of stomach contents identified four distinct groups: browsers of leathery brown macroalgae (Siganus canaliculatus, S. javus), croppers of red and green macroalgae (S. argenteus, S. corallinus, S. doliatus, S. spinus) and mixed feeders of diverse algal material, cyanobacteria, detritus and sediment (S. lineatus, S. punctatissimus, S. punctatus, S. vulpinus). Surprisingly, the diet of the fourth group (S. puellus) contained very little algal material (22.5 %) and was instead dominated by sponges (69.1 %). Together with this variation in diet, the distribution of rabbitfishes displayed clear cross-shelf variation. Biomass was greatest on inner-shelf reefs (112.7 ± 18.2 kg.ha−1), decreasing markedly on mid- (37.8 ± 4.6 kg.ha−1) and outer-shelf reefs (9.7 ± 2.2 kg.ha−1). This pattern was largely driven by the browsing S. canaliculatus that accounted for 50 % of the biomass on inner-shelf reefs, but was absent in mid- and outer-shelf reefs. Mixed feeders, although primarily restricted to the reef slope and back reef habitats, also decreased in abundance and biomass from inshore to offshore, while algal cropping taxa were the dominant group on mid-shelf reefs. These results clearly demonstrate the extent to which diet and distribution vary within the Siganidae and emphasise the importance of examining function on a species-by-species basis.

  • Morphology, sociality, and ecology: can morphology predict pairing behavior in coral reef fishes?
    Coral Reefs, 2013
    Co-Authors: S. J. Brandl, David R. Bellwood
    Abstract:

    Morphology can contain valuable information about the ecological performance of reef fishes, but it has rarely been used in combination with social traits. Social behavior is known to influence the ecological role of fishes; however, the ecological basis for pairing in reef fishes is not well understood. Field observations of 2,753 individuals, in 47 species in six families of biting reef fishes (Acanthuridae, Chaetodontidae, Kyphosidae, Labridae, Pomacanthidae, Siganidae), were used in combination with six morphological measurements, to examine the morphology of fishes in different social systems. A principal components analysis of morphological traits segregated species with high proportions of pairing individuals from non-pairing species along principal component 1, explaining 40.8 % of the variation. Pairing species were characterized by large eyes, concave foreheads, pointed snouts, deep bodies, and small maximum sizes. There was a significant positive relationship between these morphological traits (i.e., scores on PC1) and the prevalence of pairing within the Chaetodontidae (r 2 = 0.59; P = 0.026), Siganidae (r 2 = 0.72; P = 0.004), and Acanthuridae (r 2 = 0.82; P < 0.001). This was consistent when traits were corrected for phylogenetic effects. No pattern was evident in the scarine Labridae (r 2 = 0.15; P = 0.17). The morphological characteristics found among pairing species suggest that pairing species share common ecological traits, including foraging for small prey items in micro-topographically complex environments such as reef crevices. These ecological traits may have played a role in the evolution of pairing behavior and subsequently led to the development of reproductive patterns based on monogamy.

Michael D. Jennions - One of the best experts on this subject based on the ideXlab platform.

  • why pair evidence of aggregative mating in a socially monogamous marine fish siganus doliatus Siganidae
    Royal Society Open Science, 2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    Many species live in stable pairs, usually to breed and raise offspring together, but this cannot be assumed. Establishing whether pairing is based on mating, or an alternative cooperative advantage, can be difficult, especially where species show no obvious sexual dimorphism and where the act of reproduction itself is difficult to observe. In the tropical marine fishes known as rabbitfish (Siganidae), half of extant species live in socially monogamous, territorial pairs. It has been assumed that partnerships are for mating, but the reproductive mode of pairing rabbitfish is currently unconfirmed. Using passive acoustic telemetry to track movements of fishes belonging to one such species (Siganus doliatus), we provide the first evidence that paired adult fish undertake highly synchronized migrations with multiple conspecifics on a monthly cycle. All tagged individuals migrated along the same route in three consecutive months and were absent from home territories for 2–3 days just after the new moon. The timing and directionality of migrations suggest that S. doliatus may form spawning aggregations, offering the potential for exposure to multiple reproductive partners. The finding raises fundamental questions about the basis of pairing, mate choice and partnership longevity in this family.

  • Why pair? Evidence of
    2015
    Co-Authors: David R. Bellwood, Rebecca J. Fox, Michael D. Jennions
    Abstract:

    aggregative mating in a socially monogamous marine fish (Siganus doliatus, Siganidae). R. Soc. open sci. 2: 150252

Charleux Michel - One of the best experts on this subject based on the ideXlab platform.

  • New taxonomic records and regional trends for the Marquesan Prehistoric Marine Fishery, Eiao Island, Polynesia
    New Zealand Archaeological Association, 2018
    Co-Authors: Lambrides, Ariana B. J., Weisler Marshall, Charleux Michel
    Abstract:

    Eiao Island (39.2 km(2), 577 m elevation), situated at the northern extent of the Marquesas Archipelago, features rocky and steep coastlines with few sheltered embayments that allow easy access to the sea and marine resources. We report the first evidence of prehistoric fishing practices from Eiao Island based on three inland sites (possibly dating from the 14th to 17th centuries), and explore variation in fish exploitation. All previous archaeological fishing records from the archipelago are from coastal sites, with inland Eiao Island assemblages offering comparative data on site location and taxonomic composition. The Eiao Island fish bone assemblages are dominated by piscivorous taxa, specifically grouper (Serranidae). Few tuna, mackerel and bonito (Scombridae) remains were recovered from the Eiao Island assemblages, compared to reports from Ua Pou, Tahuata and Ua Huka. New family-level taxonomic records added for the archipelago include: bonefish (Albulidae), requiem sharks (Carcharhinidae), butterflyfish (Chaetodontidae), flagtail (Kuhliidae), damselfish (Pomacentridae) and rabbitfish (Siganidae). These results further contribute to our understanding of prehistoric Marquesan fishing practices and allow elucidation of subsistence in coastal versus inland settings, variability in taxonomic composition between islands of the archipelago, and importantly inform on humanenvironment interactions in East Polynesia

  • New taxonomic records and regional trends for the Marquesan prehistoric marine fishery, Eiao Island, Polynesia
    New Zealand Archaeological Association, 2018
    Co-Authors: Lambrides Ariana, Weisler Marshall, Charleux Michel
    Abstract:

    Eiao Island (39.2 km2, 577 m elevation), situated at the northern extent of the Marquesas Archipelago, features rocky and steep coastlines with few sheltered embayments that allow easy access to the sea and marine resources. We report the first evidence of prehistoric fishing practices from Eiao Island based on three inland sites (possibly dating from the 14th to 17th centuries), and explore variation in fish exploitation (NISP = 1021; MNI = 157). All previous archaeological fishing records from the archipelago are from coastal sites, with inland Eiao Island assemblages offering comparative data on site location and taxonomic composition. The Eiao Island fish bone assemblages are dominated by piscivorous taxa, specifically grouper (Serranidae). Few tuna, mackerel and bonito (Scombridae) remains were recovered from the Eiao Island assemblages, compared to reports from Ua Pou, Tahuata and Ua Huka. New family-level taxonomic records added for the archipelago include: bonefish (Albulidae), requiem sharks (Carcharhinidae), butterflyfish (Chaetodontidae), flagtail (Kuhliidae), damselfish (Pomacentridae) and rabbitfish (Siganidae). These results further contribute to our understanding of prehistoric Marquesan fishing practices and allow elucidation of subsistence in coastal vs. inland settings, variability in taxonomic composition between islands of the archipelago, and importantly inform on human-environment interactions in East Polynesia

Thomas H. Cribb - One of the best experts on this subject based on the ideXlab platform.

  • A re-evaluation of diversity of the Aporocotylidae Odhner, 1912 in Siganus fuscescens (Houttuyn) (Perciformes: Siganidae) and associated species
    Systematic Parasitology, 2017
    Co-Authors: Xena Brooks, Thomas H. Cribb, Russell Q.-y. Yong, Scott C. Cutmore
    Abstract:

    The aporocotylid fauna of the mottled spinefoot, Siganus fuscescens (Houttuyn), from Moreton Bay, Queensland, Australia, was characterised using a combined morphological and molecular approach. Four aporocotylid species were identified, three belonging to the genus Ankistromeces Nolan & Cribb, 2006 and one to Cardicola Short, 1953. Specimens of Cardicola matched an undescribed species from the same host and locality; this species is described as Cardicola mogilae n. sp. Phylogenetic analyses of ITS2 and 28S data showed that C . mogilae n. sp. forms a strongly supported clade with other Cardicola species from siganid fishes. We record Ankistromeces olsoni Nolan & Cribb, 2006 in Moreton Bay for the first time, redescribe A . dunwichensis Nolan & Cribb, 2006 on the basis of new specimens and sequence data and re-report Ankistromeces sp. X from Moreton Bay based on molecular data. We review the status of the ten putative species of aporocotylids reported from siganids. Small variation in ITS2 rDNA sequences, in association with different geographic localities, was previously used to separate Cardicola lafii Nolan & Cribb, 2006 from C . parilus Nolan & Cribb, 2006, C. bartolii Nolan & Cribb, 2006 from C. watsonensis Nolan & Cribb, 2006, C . tantabiddii Nolan & Cribb, 2006 from Cardicola sp. 2, Ankistromeces sp. Y from A . olsoni and Ankistromeces sp. X from Ankistromeces sp. Z. These five combinations are reinterpreted as each representing a single species; Cardicola lafii is recognised as the senior synonym of C . parilus and C. bartolii as the senior synonym of C. watsonensis . This study thus suggests that six, rather than ten, species should be recognised as infecting S . fuscescens . This richness remains greater than is known for any other fish species and siganids are, so far, unique among fishes in harbouring two strongly radiated lineages of aporocotylids.

  • a review of the genus sclerocollum schmidt paperna 1978 acanthocephala cavisomidae from rabbitfishes Siganidae in the indian and pacific oceans
    Systematic Parasitology, 2016
    Co-Authors: Sylvie Pichelin, Lesley R Smales, Thomas H. Cribb
    Abstract:

    Seven of the eleven species of Siganus Richardson (Siganidae) collected off the coasts of Australia, New Caledonia, French Polynesia and Palau were infected with species of Sclerocollum Schmidt & Paperna, 1978 (Acanthocephala: Cavisomidae). A Principal Component Analysis (PCA) and a Discriminant Analysis were performed on a morphometric dataset of specimens of Sclerocollum including borrowed type-specimens of Sc. rubrimaris Schmidt & Paperna, 1978 from the Indian Ocean and of Sc. robustum Edmonds, 1964, the only acanthocephalan species known previously from an Australian siganid. These analyses showed that the lengths of proboscis hooks were useful variables for separating specimens into groups and supported the presence of two known species (Sc. robustum and Sc. rubrimaris) and one new species (Sc. australis n. sp.) in Australian waters. We found Sc. robustum in Siganus lineatus (Valenciennes) from off Queensland and Sc. rubrimaris in S. fuscescens (Houttuyn) from off Western Australia and Queensland, S. punctatissimus Fowler & Bean from off Queensland and S. argenteus (Quoy & Gaimard), S. corallinus (Valenciennes), S. canaliculatus (Park) and S. doliatus Guerin-Meneville from off New Caledonia (all new host and locality records) which we compared with museum specimens of Sc. rubrimaris from S. rivulatus Forsskal & Niebuhr and S. argenteus [as S. rostratus (Valenciennes)] from the Red Sea. The third species, Sclerocollum australis n. sp., was found only in S. corallinus and S. doliatus from off Queensland. Sclerocollum australis n. sp. can be distinguished from its congeners by a unique combination of characters of the proboscis armature, including lengths of hooks 1–7. Specimens of Sclerocollum were also found in Zebrasoma velifer (Bloch) (Acanthuridae) from off Queensland, and Coradion altivelis McCulloch (Chaetodontidae) and Heniochus acuminatus (Linnaeus) (Chaetodontidae) from off New Caledonia. No acanthocephalans were found in siganids collected from Palau (Micronesia) or Moorea (French Polynesia) or Moreton Bay and Noosa (Queensland, Australia). We found no acanthocephalans in S. puellus (Schlegel), S. punctatus (Schneider & Forster), S. spinus (Linnaeus) or S. vulpinus (Schlegel & Muller). Evidence suggests that species of the genus Sclerocollum have travelled with S. argenteus across the Indo-Pacific with Sc. rubrimaris dispersed widely and Sc. robustum and Sc. australis n. sp. restricted to the Queensland coast, Australia.

  • cardicola short 1953 and braya n gen digenea sanguinicolidae from five families of tropical indo pacific fishes
    Zootaxa, 2006
    Co-Authors: Matthew J. Nolan, Thomas H. Cribb
    Abstract:

    A survey of Pacific coral reef fishes for sanguinicolids revealed that two species of Lutjanidae (Lutjanus argentimaculatus, L. bohar), six species of Siganidae (Siganus corallinus, S. fuscescens, S. lineatus, S. margaritiferus, S. punctatus, S. vulpinus), seven species of Chaetodontidae (Chaetodon aureofasciatus, C. citrinellus, C. flavirostris, C. lineolatus, C. reticulatus, C. ulietensis, C. unimaculatus), three species of Scombridae (Euthynnus affinis, Scomberomorus commerson, S. munroi) and three species of Scaridae (Chlorurus microrhinos, Scarus frenatus, S. ghobban) were infected with morphologically similar sanguinicolids. These flukes have a flat elliptical body, a vestigial oral sucker, a single testis, separate genital pores and a post-ovarian uterus. However, these species clearly belong in two genera based on the position of the testis and genital pores. Sanguinicolids from Lutjanidae, Siganidae, Chaetodontidae and Scombridae belong in Cardicola Short, 1953; the testis originates anteriorly to, or at the anterior end of, the intercaecal field and does not extend posteriorly to it, the male genital pore opens laterally to the sinistral lateral nerve chord and the female pore opens near the level of the ootype ( may be anterior, lateral or posterior to it) antero-dextral to the male pore. Those from Scaridae are placed in a new genus, Braya; the testis originates near the posterior end of the intercaecal field and extends posteriorly to it, the male pore opens medially at the posterior end of the body and the female pore opens posterior to the ootype, antero-sinistral to the male pore. The second internal transcribed spacer (ITS2) of ribosomal DNA from these sanguinicolids and a known species, Cardicola forsteri Cribb, Daintith & Munday, 2000, were sequenced, aligned and analysed to test the distinctness of the putative new species. Results from morphological comparisons and molecular analyses suggest the presence of 18 putative species; 11 are described on the basis of combined morphological and molecular data and seven are not because they are characterised solely by molecular sequences or to few morphological specimens (n= one). There was usually a correlation between levels of morphological and genetic distinction in that pairs of species with the greatest genetic separation were also the least morphologically similar. The exception in this regard was the combination of Cardicola tantabiddii n. sp. from S. fuscescens from Ningaloo Reef ( Western Australia) and Cardicola sp. 2 from the same host from Heron Island ( Great Barrier Reef). These two parasite/ host/location combinations had identical ITS2 sequences but appeared to differ morphologically ( however, this could simply be due to a lack of morphological material for Cardicola sp. 2). Only one putative species ( Cardicola sp. 1) was found in more than one location; most host species harboured distinct species in each geographical location surveyed ( for example, S. corallinus from Heron and Lizard Islands) and some ( for example, S. punctatus, S. fuscescens and Chlorurus microrhinos) harboured two species at a single location. Distance analysis of ITS2 showed that nine species from siganids, three from scombrids and five from scarids formed monophyletic clades to the exclusion of sanguinicolids from the other host families. Cardicola milleri n. sp. and C. chaetodontis Yamaguti, 1970 from lutjanids and chaetodontids, respectively, were the only representatives from those families that were sequenced. Within the clade formed by sanguinicolids from Siganidae there wasa further division of species; species from the morphologically similar S. fuscescens and S. margaritiferus formed a monophyletic group to the exclusion of sanguinicolids from all other siganid species.

  • An exceptionally rich complex of Sanguinicolidae von Graff, 1907 (Platyhelminthes: Trematoda) from Siganidae, Labridae and Mullidae (Teleostei: Perciformes) from the Indo-West Pacific Region
    Zootaxa, 2006
    Co-Authors: Matthew J. Nolan, Thomas H. Cribb
    Abstract:

    We describe an unprecedented radiation of sanguinicolid blood flukes (Digenea: Sanguinicolidae) from two species of Labridae (Choerodon venustus and C. cauteroma), seven species of Mullidae (Mulloidichthys vanicolensis, Parupeneus barberinoides, P. barberinus, P. bifasciatus, P. cyclostomus, P. indicus and P. multifasciatus) and ten species of Siganidae (Siganus argenteus, S. corallinus, S. doliatus, S. fuscescens, S. lineatus, S. margaritiferus, S. puellus, S. punctatus, S. virgatus and S. vulpinus) from sites off Australia and Palau. The flukes were morphologically similar in having the combination of a long thread-like body, tegumental spines in lateral transverse rows, a vestigial oral sucker bearing concentric rows of fine spines, an H-shaped intestine, a cirrus-sac, a notch level with the male genital pore, a lateral or post-ovarian uterus, a uterine chamber and separate genital pores. These species are divided into two genera on the basis of testis number. Sanguinicolids from Siganus fuscescens have a single large testis between the intestinal bifurcation and the ovary and are placed in Ankistromeces Nolan & Cribb, 2004. Species from the remaining nine species of Siganidae, Labridae and Mullidae are placed in Phthinomita n. g.; these species have two testes, the anterior testis being large and between the intestinal bifurcation and the ovary whereas the small posterior testis is at the posterior end of the body and appears rudimentary or degenerate and probably non-functional. The second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) from 29 host/parasite/location combinations (h/p/l) was sequenced together with that of Ankistromeces mariae Nolan & Cribb, 2004 for comparison. From 135 samples we found 19 distinct genotypes which were interpreted as representing at least that many species. Replicate sequences were obtained for 25 of 30 h/p/l combinations (including A. mariae); there was no intraspecific variation between replicates sequences for any of these. Interspecific variation ranged from 1–41 base differences (0.3–12.7% sequence divergence). The 19 putative species were difficult to recognise by morphological examination. We describe 13 new species; we do not describe (=name) six species characterised solely by molecular sequences and three putative species for which morphological data is available but for which molecular data is not. We have neither morphological nor molecular data for sanguinicolids harboured in five hosts species (Siganus margaritiferus, S. puellus, Choerodon cauteroma, Parupeneus indicus and P. multifasciatus) in which we have seen infections. Where host species were infected in different localities they almost always harboured distinct species. Some host species (for example, S. argenteus and S. lineatus from Lizard Island) harboured two or three species in a single geographical location. This suggests that, for parts of this system, parasite speciation has outstripped host speciation. Distance analysis of ITS2 showed species from each host family (Siganidae, Mullidae and Labridae) did not form monophyletic clades to the exclusion of species from other host families. However, a host defined clade was formed by the sequences from sanguinicolids from S. fuscescens.