Larval development of the pedunculate barnacles Octolasmis angulata Aurivillius 1894 and Octolasmis cor Aurivillius 1892 (Cirripedia: Thoracica: Poecilasmatidae) from the gills of the mud crab, Scylla tranquebarica Fabricius, 1798.

Detailed studies of larval development of Octolasmis angulata and Octolasmis cor are pivotal in understanding the larval morphological evolution as well as enhancing the functional ecology. Six planktotrophic naupliar stages and one non-feeding cyprid stage are documented in details for the first time for the two species of Octolasmis. Morphologically, the larvae of O. angulata and O. cor are similar in body size, setation patterns on the naupliar appendages, labrum, dorsal setae-pores, frontal horns, cyprid carapace, fronto-lateral gland pores, and lattice organs. Numbers of peculiarities were observed on the gnathobases of the antennae and mandible throughout the naupliar life-cycle. The setation pattern on the naupliar appendages are classified based on the segmentation on the naupliar appendages. The nauplius VI of both species undergoes a conspicuous change before metamorphosis into cyprid stage. The cyprid structures begin to form and modify beneath the naupliar body towards the end of stage VI. This study emphasises the importance of the pedunculate barnacle larval developmental studies not only to comprehend the larval morphological evolution but also to fill in the gaps in understanding the modification of the naupliar structures to adapt into the cyprid life-style.

Teraplectanum n. g. (Monogenea: Diplectanidae) from the banded grunter fish, Terapon theraps Cuvier (Perciformes: Terapontidae), off Peninsular Malaysia.

A new genus of the Monogenea, Teraplectanum n. g., is proposed for two new species of diplectanids found on the gills of Terapon theraps Cuvier collected off Carey Island, Peninsular Malaysia. The genus is based on a unique arrangement of the male reproductive system. In the new species spermatozoa stored in the seminal vesicle and secretions stored in the prostatic reservoir are transferred into, and mixed to form semen within, a special sclerotized auxiliary piece (SAP), and not within the copulatory tube as occurs in the majority of monogeneans. Teraplectanum species also possess a unique sclerotized vaginal loop through which the vaginal tube passes en route from the vaginal pore to the seminal receptacle. The two new species are Teraplectanum crassitubus n. sp. (type species) and T. angustitubus n. sp. They differ from each other mainly in the morphology of their copulatory tube: in T. crassitubus, the proximal region of this tube is thicker compared to the slender proximal region in T. angustitubus, although in both cases the tube tapers and twists distally. Of the known diplectanid species, only Diplectanum undulicirrosum Zhang et al., 2000 (currently considered incertae sedis) possesses such sclerotized hard parts, which suggests the same type of arrangement of the male reproductive system. Consequently, D. undulicirrosum is re-assigned to this new genus as Teraplectanum undulicirrosum (Zhang et al., 2000) n. comb. The copulatory tube of T. undulicirrosum is similar to the slender, undulating copulatory tube of T. angustitubus but does not taper distally as in the latter species.

A description of two new species of Ligophorus Euzet & Suriano, (Monogenea: Ancyrocephalidae) from Malaysian mugilid fish using principal component analysis and numerical taxonomy.

Ligophorus belanaki n. sp. and Ligophorus kederai n. sp. are described from Liza subviridis Valenciennes, 1836 and Valamugil buchanani Bleeker, 1854, respectively. Ligophorus kederai n. sp. has fenestrated ventral anchors, while in L. belanaki n. sp. the ventral anchor is not fenestrated. Ligophorus belanaki n. sp. is similar to L. careyensis, one of its coexisting congeners, in the overall shape and size of hard parts, but differs in having a flat median piece in the structure of the AMP (antero-median protuberance of the ventral bar), copulatory organ with non-ornamented initial part and longer vaginal tube, compared to raised median piece in the AMP, ornamented initial part and comparatively shorter vaginal tube in L. careyensis. Ligophorus kederai n. sp. is similar to L. fenestrum, a coexisting congener, in having fenestrated ventral anchors, but differs in having longer points and narrower base. Ligophorus fenestrum, unlike L. kederai n. sp., also possesses fenestrated dorsal anchors. The principal component analysis (PCA) scatterplots indicate that the two new and eight known Ligophorus species from Malaysian mugilids can be differentiated based on the morphometries of their anchors, ventral bars and copulatory organ separately and when combined together. Numerical taxonomy (NT) analyses based on Jaccard's Index of Similarity and neighbour-joining clustering, is used to facilitate comparison of these two new species with the 50 known Ligophorus based on morphological and metric characters. The two new species are different from each other and the other 50 species in the overall shapes and sizes of hard parts, as indicated by the NT analyses.

The life-cycle of Spirometra species from Peninsular Malaysia.

The life-cycle of Malaysian Spirometra spp. was studied under experimental conditions in the laboratory. The Cyclops were reared as the first intermediate host, the hamster as the experimental second intermediate host and cat as the definitive host. Maturation and hatching of eggs took 6 to 12 days by incubation at temperature 30 ºC. The hatched coracidium measured 46 x 34 µm. The Cyclops used were susceptible to the coracidial infection. The procercoid older than 5 days in the Cyclop body cavity had minute spines at the anterior end, calcium corpuscles in the body parenchyma and the cercomer at the posterior end. Procercoids 10 to 14 days old were infective to hamster. The plerocercoids from the hamster after 30 days were long and slender and were infective to cats. The plerocercoids experimentally inoculated to cats developed to adult worms and began to produce eggs between 10 to 60 days. Based on the results that have been obtained, a complete life-cycle was successfully elucidated in the laboratory and hamster was identified to be a good laboratory model for a second intermediate host of Spirometra sp.

Two new species of ancyrocephalid monogeneans from Lethrinus rubrioperculatus Sato (Perciformes: Lethrinidae) off New Caledonia, with the proposal of Lethrinitrema n. g.

Lethrinitrema gibbus n. g., n. sp. and L. dossenus n. sp. are described from the fish Lethrinus rubrioperculatus Sato collected off New Caledonia, South Pacific. Members of Lethrinitrema n. g. (Ancyrocephalidae) are characterised by having two pyriform haptoral reservoirs and ventral anchors with lateral grooves. The elongate tubular distal end of each reservoir bifurcates, draining into a superficial lateral groove on each side of the ventral anchors. The haptoral reservoirs are postulated to store secretory products which assist in attachment to the host. Lethrinitrema spp. also possess tandem gonads, a male copulatory organ without an accessory piece or with thinly sclerotised accessory piece, and a dextrolateral, non-sclerotised vaginal bulb. The two new species have small, poorly demarcated haptors with small haptoral armament and a crown-like piece on the tip of the inner root of the ventral anchors. They differ from each other in the shape and size of the ventral bar and male copulatory organ (40-45 µm in length in L. gibbus vs 24-30 µm in L. dossenus). Three other species, previously included in Haliotrema Johnston & Tiegs, 1922, are transferred to Lethrinitrema, i.e. L. chrysostomi (Young, 1968) n. comb., L. fleti (Young, 1968) n. comb. (both briefly redescribed from paratypes) and L. lethrini (Yamaguti, 1937) n. comb. All species of Lethrinitrema parasitise Lethrinus spp. (Lethrinidae), and there is evidence for the existence of further Lethrinitrema spp. on Lethrinus spp. in the Indo-Pacific region.

A novel alternative method for 3D visualisation in Parasitology: the construction of a 3D model of a parasite from 2D illustrations.

Three-dimensional (3D) models of the marginal hooks, dorsal and ventral anchors, bars and haptoral reservoirs of a parasite, Sundatrema langkawiense Lim & Gibson, 2009 (Monogenea) were developed using the polygonal modelling method in Autodesk 3ds Max (Version 9) based on two-dimensional (2D) illustrations. Maxscripts were written to rotate the modelled 3D structures. Appropriately orientated 3D haptoral hard-parts were then selected and positioned within the transparent 3D outline of the haptor and grouped together to form a complete 3D haptoral entity. This technique is an inexpensive tool for constructing 3D models from 2D illustrations for 3D visualisation of the spatial relationships between the different structural parts within organisms.

Species of Neohaliotrema Yamaguti, 1965 (Monogenea: Ancyrocephalidae) from the pomacentrid Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia, with a revised diagnosis of the genus and a key to its species.

Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible into two groups, the 'maomao group', with two pairs of morphometrically modified 'marginal' hooks and a fenestrated haptor, and the 'gracile group', with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the 'maomao group'. It is suggested that the more complex Neohaliotrema species of the 'maomao group' have modified hooks 1 and 2 on a haptoral 'isthmus' between two large apertures, i.e. 'windows', whereas the less complex species lacking these features are those of the 'gracile group'. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the 'maomao group'. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented.

Description of Sinodiplectanotrema malayanum n. sp. (Monogenea: Diplectanidae), with comments on the taxonomic position of the genus.

Monogeneans identified as Sinodiplectanotrema malayanum n. sp. were collected from the fish Pennahia anea (Sciaenidae) off the west coast of Peninsular Malaysia. The new species is recognised on the basis of morphometrical differences in the anchors, marginal hooks and eggs and apparent differences in the 28S rDNA sequence data. The new species possesses features (ovary looping the intestinal caecum, body spines, a vagina and haptoral reservoirs) not noted in the original description of the type and only other species of the genus, S. argyrosomus Zhang, 2001, necessitating the re-assignment of the genus to the Diplectanidae Monticelli, 1903, a move which is supported by 28S rDNA evidence. Sinodiplectanotrema is redefined on the basis of the observation of several features not included in the original diagnosis.

Trianchoratus longianchoratus sp. n. (Monogenea: Ancyrocephalidae: Heteronchocleidinae) from Channa lucius (Osteichthyes: Channidae) in Peninsular Malaysia.

One new and three previously described species of Trianchoratus Price et Berry, 1966 were collected from the gills of Channa lucius (Cuvier) and Channa striata (Bloch) from the Bukit Merah Reservoir, Perak and Endau-Rompin, Pahang, Peninsular Malaysia. They are Trianchoratus longianchoratus sp.n., T. malayensis Lim, 1986 and T. pahangensis Lim, 1986 from C. lucius, and T. ophicephali Lim, 1986 from C. striata. The new species differs from the Trianchoratus species hitherto described from channids and anabantoids in having two ventral anchors with a long curved inner root and one dorsal anchor with a curved inner root and lacking an outer root. A table summarizing the known species of heteronchocleidins (Trianchoratus, Eutrianchoratus and Heteronchocleidus) and Sundanonchus reported from fish hosts of different families (Channidae, Helostomatidae, Anabantidae and Osphronemidae) is provided.

A new monogenean genus from an ephippid fish off Peninsular Malaysia.

Sundatrema langkawiense n. g., n. sp. (Monogenea: Ancyrocephalidae) is described from the gills of the orbfish Ephippus orbis (Bloch) (Ephippidae) off the Island of Langkawi, Malaysia, in the Andaman Sea. This new genus has the ancyrocephalid characteristics of four anchors, 14 marginal hooks and two bars, but differs from other four-anchored monogenean genera, and notably from Parancylodiscoides Caballero & Bravo Hollis, 1961 (found on the ephippids Chaetodipterus spp. off Central and South America), by having a unique combination of features. These include a muscular genital sucker and a vas deferens and vagina on the same (sinistral) side of the body. It is similar to Parancylodiscoides in having four haptoral reservoirs opening at the anchoral apertures, four anchors, similar connecting bars and small marginal hooks. The new species is characterised by the above generic features and by possessing a small, short copulatory organ lacking an accessory piece. Diplectanum longiphallus MacCallum, 1915 (previously attributed to Ancyrocephalus Creplin, 1839, Tetrancistrum Goto & Kikuchi, 1917 and Pseudohaliotrema Yamaguti, 1953) is transferred to Parancylodiscoides as P. longiphallus (MacCallum, 1915) n. comb.

Species of Triacanthinella Bychowsky & Nagibina, 1968 (Monogenea: Ancyrocephalidae) from triacanthid teleosts off Peninsular Malaysia, with a generic revision, amended diagnosis and key.

One new and four previously described species of Triacanthinella Bychowsky & Nagibina, 1968 (Monogenea) were collected from the tripodfishes Triacanthus biaculeatus and Tripodichthys blochii off Peninsular Malaysia. Triacanthinella lumutensis n. sp. from Tripodichthys blochii off Lumut, Selangor is similar to Triacanthinella principalis Bychowsky & Nagibina, 1968 in having morphologically similar types of haptoral sclerites and copulatory organ, but differs in possessing a longer copulatory tube. Also re-described are T. principalis Bychowsky & Nagibina, 1968, T. gracilis Bychowsky & Nagibina, 1968 and T. aspera Bychowsky & Nagibina, 1968 from both Triacanthus biaculeatus and Tripodichthys blochii, plus Triacanthinella longipenis Bychowsky & Nagibina, 1968 from Tripodichthys blochii and Triacanthinella tripathii Bychowsky & Nagibina, 1968 based on its type-material. In the new species, the filament loop of the anchors is associated with a sheath-like sclerite which envelops the anchor point. Such sclerites were also observed in the present specimens of Triacanthinella principalis, T. aspera, T. longipenis and T. gracilis but were not mentioned in the original descriptions. The generic diagnosis of Triacanthinella is amended and a key to the recognised species is presented. The specific names of two of the previously described species are emended from the neuter form to T. principalis and T. gracilis.

Redescriptions of species of Ancyrocephaloides Yamaguti, 1938 (Monogenea: Ancyrocephalidae) from triacanthid fishes caught off Peninsular Malaysia and a report of their haptoral secretions.

Numerous specimens of Ancyrocephaloides triacanthi Yamaguti, 1938 and A. chauhani Bychowsky & Nagibina, 1975 were collected from two triacanthid fishes, Triacanthus biaculeatus and Tripodichthys blochii, off Peninsular Malaysia. The two monogenean species are redescribed and considered to be the only valid species of Ancyrocephaloides Yamaguti, 1938. Examinations of these worms revealed new features, e.g. the presence of exudates (both net-like and bundle-like) and superficial grooves in the anchors in both species, which necessitated re-descriptions of the two species and amendments to the generic diagnosis. Both species have relatively small anchors with two lateral superficial grooves along the shaft and point, peduncular glands and four large, pyriform secretory reservoirs in the peduncular-haptoral region, each with a single tubular extension to an associated anchor, and net-like structures (exudate) attached to the anchors. The net-like structures are one of the external manifestations of the secretion produced in the peduncular glands and stored in the pyriform secretory reservoirs. When released within the gill-tissue of the host, the exudate is in the form of bundles which extend within the gill-filament. The small anchors convey secretions from the secretory reservoirs via lateral superficial grooves into the gills as the anchors pierce the host tissue for attachment. The secretion coagulates as left and right thread-like bundles of exudate within the gill tissues and is only apparent as nets when it is released into the surrounding water. The recurved point of the anchor and position of the point of exudation allow the nets to remain attached to the anchor point, even after the detachment of the anchors from the gill tissue. This exudate possibly acts somewhat like a 'belay device' or 'safety belt', preventing the parasite from being washed away by the respiratory current during the onset of its leech-like locomotion, as well as assist the relatively small anchors in attachment.

Diplectanocotyla Yamaguti, 1953 (Monogenea: Diplectanoidea) from Megalops cyprinoides (Broussonet) (Teleostei: Megalopidae) off Peninsular Malaysia.

Two known and two new species of Diplectanocotyla Yamaguti, 1953 (D. gracilis Yamaguti, 1953, D. megalopis Rakotofiringa & Oliver, 1987, D. langkawiensis n. sp. and D. parva n. sp.) were collected from Megalops cyprinoides (Megalopidae) off Langkawi, Kedah and Matang, Perak, Peninsular Malaysia. All four species possess similar types of sclerotised male and female reproductive structures and similar soft anatomical features. The squamodisc sclerites of all four species have spine-like projections with varying degrees of visibility and shapes (sharp-pointed to triangular). In D. megalopis and D. langkawiensis n. sp. the spines are sharp-pointed and distinct on sclerites from rows 5-6 onwards. In D. gracilis and D. parva n. sp. the sclerite spines are triangular, lightly sclerotised and occur on almost all of the sclerites. D. parva n. sp. has comparatively the smallest set of anchors, bars, squamodiscs and squamodisc suckers. The anchors and bars of the other three species are almost similar in overall size, and the main distinguishing feature is the relative lengths of the inner and outer roots of the ventral anchors. In D. gracilis the outer root is very much smaller than the inner root and they are disposed almost at a right angle to each other. In D. megalopis the outer root is usually about half the length of the inner root and the roots are inclined at c.60 degrees to each other. In D. langkawiensis n. sp. the roots are inclined at c.40 degrees degrees and the outer root is of a similar length or only slightly shorter than the inner root. The openings of the two squamodisc suckers of all four Diplectanocotyla species are surrounded by tiny scale-like spines. Bifid tegumental spines are found in the posterior region of all four species, differing only in their extent: in D. parva n. sp. the tegumental spines are only distributed in the peduncular region and not beyond, whilst in the other three species the tegumental spines extend from the posterior level of the testis to the end of the peduncle. An amended diagnosis of Diplectanocotyla and a key to its species are appended.

Haliotrema banana sp. n. (Monogenea: Ancyrocephalidae) from Bodianus perditio (Perciformes: Labridae) off New Caledonia.

Sixteen labrid species, including four Bodianus spp., were examined in New Caledonia (South Pacific) and monogeneans were found only on Bodianus perditio (Quoy et Gaimard). This species, Haliotrema banana sp. n., is the second Haliotrema species to be described from the labrids, the first being Haliotrema bodiani Yamaguti, 1968 from Bodianus albotaeniatus (Valenciennes), previously designated as B. bilunulatus (Lacépède). The new species is similar to H. bodiani in soft reproductive parts but differs from it in the morphologies of the hard haptoral parts, mainly in the shape of the dorsal bar (bar-shaped vs V-shaped in H. bodiani) and ventral bar. It is similar to Haliotrema spirale Yamaguti, 1968 and Haliotrema minutospirale Yamaguti, 1968 in the shape of the anchors and bars but differs from them in the detailed structures of the copulatory organ and vaginal system.

Diplectanids (Monogenea) on the archerfish Toxotes jaculatrix (Pallas) (Toxotidae) off Peninsular Malaysia.

Two new and two previously described species of diplectanid monogeneans (Heteroplectanum flabelliforme n. sp., Diplectanum sumpit n. sp., D. jaculator Mizelle & Kritsky, 1969 and D. toxotes Mizelle & Kritsky, 1969) were collected from archerfish Toxotes jaculatrix off the Island of Langkawi, Kedah and off Perak, Malaysia. The reproductive systems and squamodiscs of D. jaculator and D. toxotes are described for the first time. D. sumpit n. sp. differs from D. toxotes and D. jaculator in a having a small curved copulatory tube with a distinct accessory piece, compared to the long, tubular copulatory tube of D. jaculator and the slender tube of D. toxotes. D. sumpit n. sp. also differs from D. toxotes in having a larger ventral bar and larger squamodiscs. H. flabelliforme n. sp. differs from all known Heteroplectanum species in the shape and size of the squamodiscs, the arrangement of the sclerites in the squamodiscs, the extremely large ventral bar and the short, curved, non-spinous copulatory tube.

Sodium dodecyl sulphate as a rapid clearing agent for studying the hard parts of monogeneans and nematodes.

Hard structures of helminths have often been used for taxonomic identification but are usually not clearly defined when treated with conventional methods such as ammonium picrate-glycerin for monogeneans and glycerin for nematodes. The present study reports a rapid and simple technique to better resolve the hard parts of selected monogeneans and nematodes using 5-10% alkaline sodium dodecyl sulphate (SDS). In comparison with established methods, SDS-treated worms become more transparent. In monogeneans treated with SDS, clear details of the hooks, hook filaments, anchors, bars and the sclerotized copulatory organs could be observed. In SDS-treated nematodes, spicules and ornamentations of the buccal capsules could be clearly seen.

Fine structure of the anterior adhesive apparatus (head organs) of Bravohollisia gussevi Lim, 1995 (Monogenea: Ancyrocephalidae).

A study of the anterior adhesive apparatus (head organs) of Bravohollisia gussevi Lim, 1995 was carried out using light and electron microscopy. The anterior adhesive apparatus or head organs in B. gussevi comprise 6 circular openings or apertures in the antero-lateral region, associated pits lined with specialized microvillous tegument that differ from the general body tegument, a bundle of ducts, and uninucleate gland cells located lateral to the pharynx. The uninucleate glands of the anterior adhesive apparatus (head organs) comprise 2 types of cells, one kind of cell producing rod-like bodies (S1) and the other oval bodies (S2). The S1 bodies are filled with numerous, less electron-dense vesicles in an electron-dense matrix, while S2 bodies have no vesicles but contain a more homogeneous electron-dense matrix. Interlinking band-like structures were observed between S1 bodies. Similar band-like structures were found between S2 bodies. The formation of S1 bodies was followed by transmission electron microscopy. However, the formation of S2 bodies was unclear and could not be resolved. Uniciliated structures were also observed around the openings of the anterior adhesive apparatus. Each uniciliated structure is usually associated with an opening of a gland cell producing granular, electron-dense, secretory bodies, which differ from the secretions produced by the lateral gland cells of the anterior adhesive apparatus.

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: X. six new species of Thaparocleidus Jain, 1952 (Ancylodiscoididae) from Pangasius micronema.

The examination of gill parasites from Pangasius micronemao Bleeker, 1847 (Siluriformes, Pangasiidae) in Southeast Asia revealed the presence of nine species of Monogenea. Two (Thoparocleidus brevicochleus Pariselle, Lim & Lambert, 2001 and T. sinespinoe Pariselle, Lim & Lambert, 2001) have been previously described. Among the others, six species, belonging to Thaporocleidus Jain, 1952 (Monogenea, Ancylodiscoididae) as defined by Lim (1996) and Lim et al. (2001), are considered new species: T. tacitus n. sp., T. summagracilis n. sp., T. portentosus n. sp., T rukyonii n. sp., T. durandi n. sp., and T. lebrunce n. sp. The remaining species is represented by too few individuals to be conclusively described.

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: VIII. Four new species of Thaparocleidus Jain, 1952 (Ancylodiscoididae) from Pangasius polyuranodon and P. elongatus.

The examination of gill parasites from Pangasius polyuranodon Bleeker, 1852 and P. elongatus Pouyaud, Gustiano & Teugels, 2002 (Siluriformes, Pangasiidae) in Southeast Asia revealed the presence of four new species of Monogenea all belonging to Thaparocleidus Jain, 1952 (Monogenea, Ancylodiscoididae) as defined by Lim (1996) and Lim et al. (2001): T. furcus n. sp., T. infundibulus n. sp., T. sudartoi n. sp. and T. turbinatio n. sp.

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: IX. Two new species of Thaparocleidus Jain, 1952 (Ancylodiscoididae) from Pangasius mahakamensis.

The examination of gill parasites from P. mahakamensis Pouyaud, Gustiano & Teugels, 2002 (Siluriformes, Pangasiidae) in Southeast Asia revealed the presence of three species of Monogenea. One (Thaparocleidus caecus (Mizelle & Kritsky, 1969)) had been previously described. The other two, belonging to Thaparocleidus Jain, 1952 (Monogenea, Ancylodiscoididae) as defined by Lim (1996) and Lim et al. (2001), are considered new species: T. pouyaudi n. sp. and T. teugelsi n. sp.