The taxonomy, systematics and evolutionary biology of the Gyliauchenidae Fukui, 1929 (1918) (Platyhelminthes: Digenea)

Hall, Kathryn Ann (2004). The taxonomy, systematics and evolutionary biology of the Gyliauchenidae Fukui, 1929 (1918) (Platyhelminthes: Digenea) PhD Thesis, School of Molecular and Microbial Sciences, The University of Queensland.

       
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Author Hall, Kathryn Ann
Thesis Title The taxonomy, systematics and evolutionary biology of the Gyliauchenidae Fukui, 1929 (1918) (Platyhelminthes: Digenea)
School, Centre or Institute School of Molecular and Microbial Sciences
Institution The University of Queensland
Publication date 2004-01-01
Thesis type PhD Thesis
Supervisor Dr. Thomas Cribb
Dr. Rod Bray
Total pages v.1 & v.3
Collection year 2004
Language eng
Subjects L
270501 Animal Systematics, Taxonomy and Phylogeny
780105 Biological sciences
Formatted abstract

This thesis presents a review of the taxonomy, systematics and evolutionary biology of the Gyliauchenidae Fukui, 1929 (1918). A review of the literature, including taxonomic descriptions and host records, the systematic history and biological observations has been conducted. The most recent review of the family, by Nahhas & Wetzel (1995), recognised 25 species in six genera; Telotrema Ozaki, 1933 was included as a junior synonym of Gyliauchen. The genem Petalocotyle Ozaki, 1934 and Robphildollfusium Paggi & Orecchia, 1963 were not attributed to the Gyliauchenidae in the review of Nahhas & Wetzel. This review recognises all genera covered by Nahhas & Wetzel in addition to Telotrema, Petalocotyle and Robphildollfusium. Progyliauchen Shalaby & Hassanine, 1997 is recognised as valid and six new genera are proposed. I have expanded the group to comprise 68 species within 16 genera classified in three subfamilies. 

The Gyliauchenidae is a morphologically distinctive family of trematodes which is generally restricted to reef-endemic herbivorous fishes of the Indo-West Pacific; over 4 300 individual host fishes from Indo-Pacific waters have been examined during the period of this study. The recovered gyliauchenids have been examined using a combination of morphological and molecular techniques to examine the taxonomy, systematics and biology of the group. I present a new method for the preparation of gyliauchenid specimens for microscopy. The ultrastructure of the digestive system and morphology of the male terminal genitalia has been examined by histological sectioning. Genetic characterisation of gyliauchenid species, using a combination of four genetic loci (internal transcribed spacer (ITS2) and partial large subunit (28S D1-D3) rDNA and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) and large subunit (16S) mtDNA genes), has been performed for use in the molecular discrimination of species and for the phylogenetic inference of the interrelationships of the group. A morphological matrix, using morphometric data, has also been used for the cladistic analysis of gyliauchenid interrelationships. The results from the phylogenetic studies have been used to propose a systematic classification for the Gyliauchenidae and to explore the observed patterns of host and geographical distribution and morphological evolution of the group. 

The taxonomy presented here incorporates a new diagnosis of the family, which recognises two synonyms, Dissotrematidae Goto & Matsudaira, 1918 and Robphildollfusiidae Paggi & Orecchia, 1963. The recognition of the family-group name Gyliauchenidae Fukui, 1929 (1918) is justified within the recommendations of the International Code for Zoological Nomenclature (ICZN). The Gyliauchenidae is united by the synapomorphic morphology of the male terminal genitalia, in which the prostate gland cell bodies are external to the cirrus-sac. Three subfamilies, Gyliaucheninae Fukui, 1929 (1919), Petalocotylinae Ozaki, 1937 and RobphildoUfusiinae Paggi & Orecchia, 1963 are diagnosed. Ichthyotreminae Caballero & Bravo-Hollis, 1952 and Apharyngogyliaucheninae Yamaguti, 1958 are recognised as junior synonyms of Gyliaucheninae. The Gyliaucheninae is united by the posterior position of the ventral sucker and is proposed to comprise 14 genera; a dichotomous key to genera is presented. The composition of each of these genera is comprehensively reviewed and keys to species are provided.

Gyliauchen Nicoll, 1915 comprises eight species, of which six are new, from siganid fishes; the type species, G. tarachodes Nicoll, 1915 was described from an undescribed species of Tachysurus (Ariidae). A new generic diagnosis is provided and Dissotrema Goto & Matsudaira, 1918 is recognised as a junior synonym of Gyliauchen. The species of Gyliauchen are united by the ventroterminal position of the venfral sucker and the presence of a postovarian uterus. G. tarachodes and G. papillatus (Goto & Matsudaira, 1918) are redescribed. G. bylgia n. sp. is described from species of Siganus (Siganidae) from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. G. castor n. sp. is described from species of Siganus from Noumea, New Caledonia. G. cymodoce n. sp. is described from species of Siganus collected at Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. G. doris n. sp. is described from Siganus corallinus (Valenciennes, 1835) from Heron Island, Great Barrier Reef, Queensland, Australia. G. galatea n. sp. is described from species of Siganus from Heron Island, Great Barrier Reef, Queensland, Australia; one specimen is also recorded from Thalassoma lunare (Linnaeus, 1758) (Labridae) from Heron Island. G. pollux n. sp. is described from S.fuscescens (Houttuyn, 1782) from Ningaloo Reef, Ningaloo, Western Australia, Australia. G. castor and G. pollux are hypothesised as bigemminate species. The species G. indicum Gupta & Tandon, 1983, G. oligoglandulosus Gu & Shen, 1979, G. ozakii Srivastava, 1938 and Gyliauchen sp. of Nahhas & Wetzel (1995) are included as species inquirenda; Gyliauchen sp. of Toman & Kamegi (1974) is similarly not recognised and is included here as a nomen nudem. 

Affecauda n. g. is proposed for three morphologically unusual species from acanthurid and siganid fishes from the Great Barrier Reef, Australia, and is diagnosed by the combination of an elongate, slender body shape, annulation of the tegument, and a sigmoid oesophagus (or with a single loop). A. annulata n. sp. is designated as the type-species and is described from species of Naso (Acanthuridae) from Heron and Lizard islands, Great Barrier Reef, Queensland, Australia. A. rugosa n. sp. is described from Zebrasoma veliferum (Bloch, 1797) (Acanthuridae) from Noumea, New Caledonia. A. salacia n. sp. is described from Siganus corallinus (Valenciennes, 1835) from Lizard Island, Great Barrier Reef, Queensland, Australia.

Apharyngogyliauchen Yamaguti, 1942 is reviewed and diagnosed chiefly by the absence of the oesophageal bulb, in addition to the pyriform body shape. Species of Apharyngogyliauchen are known only from labroid hosts and have a wide disfribution in the Indo-West Pacific, ranging from the Red Sea to French Polynesia. The type-species, A. callyodontis Yamaguti, 1942, is redescribed and^. scarustis Gu & Shen, 1983 is recognised as a junior synonym. A. asymbletis n. sp. is proposed for specimens attributed to A. callyodontis by previous workers; A. callyodontis of Nagaty (1956) (in part), A. callyodontis of Ramadan (1986) and A. callyodontis of Rabie & Ahmed (2000), all from labroid fishes of the Red Sea, are here attributed to A. asymbletis. A. catomus n. sp. is described from scarid fishes from Heron Island, Great Barrier Reef, Queensland, Australia and Moorea, French Pacific. A. hryga n. sp. is described from Chlorurus microrhines (Bleeker, 1854) (Scaridae) from Noumea, New Caledonia. A. opisthovarius Gu & Shen, 1983, from Cirrhilabrus sp. (Labridae) from China is redescribed. The new combination of A. thalassamae (Wang, 1977) is proposed; this species was formerly attributed to Gyliauchen and is known from Thalassoma hardwicke (Bennett, 1830) (Labridae) from China. Apharyngogyliauchen sp. of Nahhas & Wetzel (1995), recorded from Scarus ghobban Forsskal, 1775 (Scaridae) collected from Laucala Bay, Suva, Fiji, is redescribed based on examination of deposited type material. Apharyngogyliauchen sp. A n. sp. is described from species of scarids from Heron Island, Great Barrier Reef, Queensland, Australia. 

Cincinnogyliauchen n. g. is proposed for eight new species from acanthuroid fishes from the Indo-West Pacific and is diagnosed by the combination of an elongate, dorso- ventrally curved body shape, presence of at least a small excretory papilla, and an oesophagus which always executes a single dextral loop crossing the midline. The monophyly of this genus is supported by genetic data. C. bellus n. sp. is designated as the type-species and is described from Zebrasoma scopas (Cuvier, 1829) (Acanthuridae) from Lizard Island, Great Barrier Reef, Queensland, Australia and Noumea, New Caledonia. C. chasmemus n. sp. is described from Z scopas from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. C. geminus n. sp. is described from Z. scopas from Lizard Island, Great Barrier Reef, Queensland and Ningaloo Reef, Ningaloo, Western Australia, Australia. C. peratus n. sp. is described from Z scopas from Moorea, French Pacific. C. procerus n. sp. is described from Z veliferum (Bloch, 1797) from Heron and Lizard islands, Great Barrier Reef, Queensland, Australia. C. raritas n. sp. is described from Naso lituratus (Forster, 1801) (Acanthuridae) from Moorea, French Pacific. C. surreptivus n. sp. is described from N. fageni Morrow, 1954 from Ningaloo Reef, Ningaloo, Western Australia, Australia. Cincinnogyliauchen sp. A n. sp. is described from N. annulatus (Quoy & Gaimard, 1852) from Lizard Island, Great Barrier Reef, Queensland, Australia. Two distinct morphological groups are recognised within Cincinnogyliauchen. The C. bellus-group comprises C. bellus, C. chasmemus, C. geminus and C. peratus and is characterised by a restriction of the vitelline follicles to X-shaped distributions cenfred at the intestinal bifurcation. The C. procerus-group comprises the remaining species and is marked by an elongate body shape and no restriction of the vitelline follicles into an X-shaped distribution. Within the C. bellus-group, C. chasmemus and C. geminus are hypothesised as bigemminate taxa.

Flagellotrema Ozaki, 1936 is recognised here principally by the possession of a looped oesophagus and the position of the genital pore posterior to the termination of the caeca. The type-species, F. convolutum Ozaki, 1936 is redescribed. F. amphitrite n. sp. is described from Prionurus maculatus Ogilby, 1887 (Acanthuridae) and species of Siganus from Heron Island, Great Barrier Reef, Queensland, Australia. 

Hadrobolbus n. g. is proposed for three species previously atfributed to Flagellotrema. These species are distinguished from Flagellotrema and united by the massive oesophageal bulb, short caeca and the symmetrical testes, which lie entirely anterior to the ventral sucker. All of the species of Hadrobolbus are parasites of chaetodontid and pomacanthid fishes of Hawaii. H. chaetodontis (Manter & Pritchard, 1962) n. comb, is designated as the type- species and is redescribed. The new combinations of H. centropygis (Yamaguti, 1970) and H. potteri (Yamaguti, 1970) are proposed and redescribed from examinations of type material. 

The monotypic Ichthyotrema Bravo-Hollis, 1952 is recognised. I. vogelsangi Caballero & Bravo-Hollis, 1952 is redescribed from voucher material from Prionurus punctatus Gill, 1862 (Acanthuridae), collected from Puerto Vallarta, Mexico. 

Leptobulbus Manter & Pritchard, 1962 is recognised as a monotypic genus. L. magnacirratus Manter & Pritchard, 1962 is redescribed from voucher material collected from scarid fishes of Hawaii. 

Medousogyliauchen n. g. is proposed for three new species from siganid fishes of the Indo-West Pacific; I also propose the new combinations of three species of Gyliauchen. This genus is defined principally by the unique double U-shaped conformation of the oesophagus. The type-species, M nahaensis (Ozaki, 1937) n. comb., is redescribed based on published accounts. M cydippe n. sp. is described from species of Siganus from Heron Island, Great Barrier Reef, Queensland, Australia. M. panope n. sp. is described from species of Siganus from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. The new combination of M parapapillatus (Nahhas & Wetzel, 1995) is proposed; G. parapapillatus Nahhas & Wetzel, 1995 and G. papillatus of Durio & Manter (1969) are synonymised. This species is known from siganid fishes of the Great Barrier Reef, Queensland, Australia and Fiji. M. spio n. sp. is described from species of Siganus from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia, Noumea, New Caledonia and Fiji. This species is recorded also from Zanclus cornutus (Zanclidae) from Heron Island. G. nahaensis of Nahhas & Wetzel (1995) (in part), G. nahaensis of Hughes-Stamm et al. (1999) and G. nahaensis of Jones et al. (2000) are recognised as synonjnns of M spio. M. volubilis (Nagaty, 1956) from siganid and scarid fishes from the Red Sea is proposed as a new combination. 

Paragyliauchen Yamaguti, 1934 is recognised as comprising two previously described species; a further five species are described from pomacanthid fishes from the Indo-West Pacific. Two morphological groups are recognised within Paragyliauchen: the P. chaetodontis-group, containing only two species, P. chaetodontis Yamaguti, 1934 and P. scaeodicliditus n. sp., and the P. arusettae-group. The type-species, P. chaetodontis, is redescribed from type material. P. scaeodicliditus is described from species of Centropyge (Pomacanthidae) from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia and Moorea, French Pacific. The following species belong to the P. arusettae-group. p. arusettae Machida, 1984 is redescribed from review of the literature. P. atractus n. sp. is described from species of Centropyge from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. P.fractoporus n. sp. is described from species of pomacanthids from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. A single specimen previously attributed to P. arusettae by Dyer et al. (1988) is here considered as a distinct species, Paragyliauchen sp. A n. sp. Paragyliauchen sp. B n. sp. is described from Pomacanthus semicirculatus (Pomacanthidae) from Ningaloo Reef, Ningaloo, Western Australia, Australia. 

The monotypic Progyliauchen Shalaby & Hassanine, 1997 is recognised by the presence of a unique conformation of the oesophagus and a four-lobed ovary. P. sigani Shalaby & Hassanine, 1997 is redescribed. 

Ptychogyliauchen n. g. is proposed for four new species from siganid fishes of the Indo-West Pacific and is distinguished from the remainder of the Gyliauchenidae principally by the possession of a uniquely double-looped oesophagus and the distinctive lining of the ejaculatory duct. P. thetidis n. sp. is designated as the type-species and is described from species of Siganus from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. P. himinglaeva n. sp. is described from S. corallinus (Valenciennes, 1835) from Lizard Island, Great Barrier Reef, Queensland, Australia. P. leucothea n. sp. is described from species of Siganus from Ningaloo, Western Australia, Australia. P. thistilbardi n. sp. is described from species of Siganus from Noumea, New Caledonia. This species is recorded also from Chaetodon citrinellus Cuvier, 1831 (Chaetodontidae) from Moorea, French Pacific. 

Telotrema Ozaki, 1933 is recognised by the straight structure of the oesophagus and the presence of a conspicuous and wide excretory papilla. The type-species, T. caudatum Ozaki, 1933 is reviewed. T. brevicaudatum n. sp. is described from Acanthurus xanthopterus Valenciennes, 1835 (Acanthuridae) from Lizard Island, Great Barrier Reef, Queensland, Australia. The new combination of T. pomacentri (Nahhas & Wetzel, 1995) is proposed from the examination of the type-specimen. 

Xenogyliauchen n. g. is proposed for two species of gyliauchenids from siganid and zanclid fishes. The type-species, X. zancli (Nahhas & Wetzel, 1995) n. comb, is redescribed and G nahaensis of Nahhas & Wetzel (1995) (in part) is recognised as a synonym. X. buseyra n. sp. is described from species of Siganus from Heron and Lizard islands, Great Barrier Reef, Queensland, Australia. 

The Petalocotylinae Ozaki, 1937 is distinguished from other subfamilies of the Gyliauchenidae by the combination of the position of the ventral sucker in the anterior half of the body and the possession of a common genital pore. The Petalocotylinae contains only one genus, Petalocotyle Ozaki, 1934, of which there are four species. The type-species, P. nipponica Ozaki, 1934, is redescribed. P. adenometra n. sp. is described from Prionurus microlepidotus Lacepede, 1804 (Acanthuridae), from Amity Point, Stradbroke Island, Queensland, Australia. P. diverticulata n. sp. is described from species of Acanthurus (Acanthuridae) from Heron and Lizard islands. Great Barrier Reef, Queensland, Australia. Petalocotyle sp. A n. sp. is described from Acanthurus blochii Valenciennes, 1835 (Acanthuridae), Noumea, New Caledonia. 

The Robphildollfusiinae Paggi & Orecchia, 1963 is diagnosed principally by the presence of separate male and female genital pores. Robphildollfusium Paggi & Orecchia, 1963 is the only genus in the subfamily. R.fractum (Rudolphi, 1819) and R. martinezgomezi Lopez-Roman, Gijon-Botella, Kim & Vilca-Chocque, 1992 are redescribed from the literature and examination of type material. 

The phylogenetic interrelationships of the Gyliauchenidae have been inferred using molecular data from four genetic loci (ITS2 and 28S rDNA and ND1 and 16S mtDNA) analysed as independent datasets and using a total evidence approach. Each dataset was analysed using the criteria of Maximum Parsimony, minimum evolution and maximum likelihood. Three different a priori weight sets were assumed for analysis of the ND1 mtDNA gene alignment. Phylogenetic relationships were also inferred by parsimony for the translation of this gene into amino acids. A morphological dataset, which combined morphometric and morphological characters, was devised and analysed by parsimony. The results of the phylogenetic analysis were used to hypothesise a classification of the Gyliauchenidae. This classification was consistent with the recognition of the three subfamilies. Within the Gyliaucheninae, two tribes were recognised: Gyliauchini and Paragyliauchini. Paragyliauchini comprises the species of the genera Paragyliauchen, Hadrobolbus and Leptobulbus. The Gyliauchini is further classified into three clades identified in the phylogenetic analysis. The Gyliauchen-group contains Gyliauchen, Apharyngogyliauchen and Xenogyliauchen. The Affecauda-clade contains Affecauda, Cincinnogyliauchen, Flagellotrema, Ichthyotrema, Ptychogyliauchen and Telotrema. The species of Medousogyliauchen are classified within a monogeneric clade. Progyliauchen is classified within the Gyliauchini as incertae sedis. 

The proposed systematic classification of the Gyliauchenidae has been used to explore macroevolutionary patterns in the observed biogeographical and host distribution of the family. The origins of the unique morphological adaptations of the group have also been investigated in an evolutionary context. Molecular data have been used to hypothesise the time of divergence of the Gyliauchenidae from a lepocreadoid ancestor. I propose that the current observed morphology and host and geographical disfribution of the Gyliauchenidae reflects a rapid, but intense, history of association with acanthuroid fishes; the distinctive morphology of the group is a direct consequence of their association with the dominant herbivorous fishes of the Indo-West Pacific.

Keyword Fishes -- Parasites
Helminths -- Classification
Additional Notes
consists of three volumes

Document type: Thesis
Collection: UQ Theses (RHD) - UQ staff and students only
 
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Created: Sat, 25 Aug 2007, 04:34:33 EST