Two new genera, Provitellus and Ovipusillus, and four new species of Monorchiidae (Digenea) from carangid fishes of queensland, Australia

Two new genera and four new species of monorchiid digeneans are described from the Great Barrier Reef and Moreton Bay, Queensland. Provitellus turrum n. g., n. sp. from Pseudocaranx dentex and Trachinotus coppingeri is characterised by the presence of vitelline follicles in the forebody, a single testis, a unipartite terminal organ and filamented eggs. Ovipusillus mayu n. g., n. sp. from Gnathanodon speciosus is characterised by the presence of two testes, vitelline follicles overlapping the ventral sucker and a large, complex cirrus-sac that contains a coiled eversible ejaculatory duct joined by the pars prostatica halfway along its length. Paramonorcheides pseudocaranxi n. sp. from Pseudocaranx dentex differs from other species described in this genus in the longer flatter forebody, entire ovary and the well-developed cirrus-sac. Chrisomon gaigai n. sp. from Trachinotus coppingeri and T botla is characterised by the unflattened forebody and transversely oval pharynx. Chrisomon is redefined to include species of Lasiotocus with a vitellarium composed of clusters of tubular acini, creating the following new combinations: C. albulae n. comb. for L. albulae Overstreet, 1969, C. ulua n. comb, for L. ulua Yamaguti, 1970 and C. weke n. comb, for L. weke Yamaguti, 1970. The diagnosis of Lasiotocus is amended accordingly and the new combinations, L. polynemi n. comb. and L. sunderbanensis n. comb., are created for C.polynemi Dutta, Hafeezullah & Manna, 1994 and C. sunderbanensis Dutta, Hafeezullah B Manna, 1994, respectively. Extrapolation of our collection data suggests that there may be as many as 80 species of monorchiids infecting carangid fishes in Australia and 180 species infecting carangids in all oceans of the world. The latter figure greatly exceeds the number of monorchiids described from all host families to date.

Chondroitin sulfates modulate axon guidance in embryonic Xenopus brain

Chondroitin sulfate proteoglycans display both inhibitory and stimulatory effects on cell adhesion and neurite outgrowth in vitro. The functional activity of these proteoglycans appears to be context specific and dependent on the presence of different chondroitin sulfate-binding molecules. Little is known about the role of chondroitin sulfate proteoglycans in the growth and guidance of axons in vivo. To address this question, we examined the effects of exogenous soluble chondroitin sulfates on the growth and guidance of axons arising from a subpopulation of neurons in the vertebrate brain which express NOC-2, a novel glycoform of the neural cell adhesion molecule N-CAM. Intact brains of stage 28 Xenopus embryos were unilaterally exposed to medium containing soluble exogenous chondroitin sulfates. When exposed to chondroitin sulfate, NOC-2(+) axons within the tract of the postoptic commissure failed to follow their normal trajectory across the ventral midline via the ventral commissure in the midbrain. Instead, these axons either stalled or grew into the dorsal midbrain or continued growing longitudinally within the ventral longitudinal tract. These findings suggest that chondroitin sulfate proteoglycans indirectly modulate the growth and guidance of a subpopulation of forebrain axons by regulating either matrix-bound or cell surface cues at specific choice points within the developing vertebrate brain. (C) 1998 Academic Press.

Lepocreadiidae (Digenea) of Australian coastal fishes: new species of Opechona Looss, 1907, Lepotrema Ozaki, 1932 and Bianium Stunkard, 1930 and comments on other species reported for the first time or poorly known in Australian waters

Opechona austrobacillaris n, sp. is described from Pomatomus saltatrix from marine sites off Western Australia and New South Wales, Australia. It differs from O. bacillaris in its elongate outline, small ventral sucker, longer pseudoesophagus (relative to the oesophagus), relatively shorter ventral sucker to ovary distance and the relatively longer post-testicular region. Lepotrema monile n. sp. is described from Pomacentrus wardi from Heron Island, Queensland. It differs from its congeners in the sphincter around the distal metraterm and the more-or-less oval ovary. Bianium spongiosum n. sp, is described from Ostracion cubicus from Lizard Island, Queensland. It differs from its congeners in lacking lateral flaps in the forebody, but in having large, internal spongiform patches in the lateral forebody. The following species are redescribed from Australian sites: Lepocreadium oyabitcha from Abudefduf whitleyi, Lizard Island; Clavogalea trachinoti from Trachinotus botla, Heron Island and T. coppingeri, New South Wales, Stradbroke Island, Queensland and Heron Island; Myzoxenus insolens from Notolabrus parilus, Western Australia; Bulbocirrus aulostomi from Aulostomus chinensis, Heron Island; Lepocreadioides orientalis [new synonyms: Bicaudum interruptum Bilqees, 1973; Lepocreadioides interruptum (Bilqees, 1973) Madhavi, Narasimhulu & Shameem, 1986; Lepocreadioides discum Wang, 1986; Lepocreadioides sp. of Karyakarte & Yadav (1976)] from Cynoglossus bilineata, Moreton Bay, Queensland; Hypocreadium patellare from Sufflamen chrysopterus, Heron Island; Echeneidocoelium indicum from Echeneis naucrates, Heron Island; Multitestis pyriformis from Epinephelus cyanopodus, Heron Island; Pseudopisthogonoporus vitellosus from Naso brevirostris, Heron Island; and Bianium hispidum from Torquigener whitleyi and T. pleurogramma, southern Queensland. Only M. solens and M. pyriformis have been reported from Australian waters before; both are new host records.

Brain region-specific studies of the excitatory behavioral effects of morphine-3-glucuronide

This study was designed to determine in rats whether morphine-3-glucuronide (M3G) produces its neuro-excitatory effects most potently in the ventral hippocampus (as has been reported previously for subanalgesic doses of opioid peptides). Guide cannulae were implanted into one of seven regions of the rat brain: lateral ventricle; ventral, CA1 and CA2-CA3 regions of the hippocampus; amygdala; striatum or cortex. After a 7 day recovery period, rats received intracerebral injections of (i) M3G (1.1 or 11 nmol) (ii) DADLE ([D-Ala(2),D-Leu(5)]enkephalin), (45 nmol, positive controls) or (iii) vehicle (deionised water), and behavioral excitation was quantified over 80 min. High-dose M3G (11 nmol) evoked behavioral excitation in all brain regions but the onset, severity and duration of these effects varied considerably among brain regions. By contrast, low-dose M3G (1.1 nmol) evoked excitatory behaviors only when administered into the ventral hippocampus and the amygdala, with the most potent effects being observed in the ventral hippocampus. Prior administration of the nonselective opioid antagonists, naloxone and beta-funaltrexamine into the ventral hippocampus, markedly attenuated low-dose M3G's excitatory effects but did not significantly alter levels of excitation evoked by high-dose M3G. Naloxone given 10 min after M3G (1.1 or 11 nmol) did not significantly attenuate behavioral excitation. Thus, M3G's excitatory behavioral effects occur most potently in the ventral hippocampus as reported previously for subanalgesic doses of opioid peptides, and appear to be mediated through at least two mechanisms, one possibly involving excitatory opioid receptors and the other, non-opioid receptors.

A review of the Apocreadiidae Skrjabin, 1942 (Trematoda : Digenea) and description of Australian species

The Apocreadiidae is reviewed and is considered to include genera recognised previously within the families Apocreadiidae, Homalometridae, Schistorchiidae, Sphincterostomatidae and Trematobrienidae. Key features of the family are extensive vitelline follicles, eye-spot pigment dispersed in forebody, I-shaped excretory vesicle, no cirrus-sac and genital pore opening immediately anterior to the ventral sucker (usually) or immediately posterior to it (Postporus Manter, 1949). Three subfamilies and 18 genera are recognised within the Apocreadiidae. The Apocreadiinae comprises Homalometron Stafford, 1904 (new syn. Barbulostomum Ramsey, 1965), Callohelmis n. g., Choanodera Manter, 1940, Crassicutis Manter, 1936, Dactylotrema Bravo-Hollis & Manter, 1957, Marsupioacetabulum Yamaguti, 1952, Microcreadium Simer, 1929, Myzotus Manter, 1940, Neoapocreadium Siddiqi & Cable, 1960, Neomegasolena Siddiqi & Cable, 1960, Pancreadium Manter, 1954, Procaudotestis Szidat, 1954 and Trematobrien Dollfus, 1950. The Schistorchiinae comprises Schistorchis Luhe, 1906, Sphincterostoma Yamaguti, 1937, Sphincteristomum Oshmarin, Mamaev & Parukhin, 1961 and Megacreadium Nagaty, 1956. The Postporinae comprises only Postporus. A key to subfamilies and genera of the Apocreadiidae is provided. It is argued that there is no convincing basis for the recognition of the genus Apocreadium Manter, 1937 and all its constituent species are combined with Homalometron. The following new combinations are proposed for species previously recognised within Apocreadium: Homalometron balistis (Manter, 1947), H. caballeroi (Bravo-Hollis, 1953), H. cryptum (Overstreet, 1969), H. longisinosum (Manter, 1937), H. manteri (Overstreet, 1970), H. mexicanum (Manter, 1937) and H. vinodae (Ahmad, 1985). Apocreadium uroproctoferum Sogandares-Bernal, 1959 is found to lack a uroproct and is made a synonym of H. mexicanum. Homalometron verrunculi nom. nov. is proposed to replace the secondarily pre-occupied H. caballeroi Lamothe-Argumedo, 1965. Barbulostomum is made a synonym of Homalometron and H. cupuloris (Ramsey, 1965) n. comb. is proposed. Neochoanodera is made a synonym of Choanodera and Choanodera ghanensis (Fischthal & Thomas, 1970) n. comb. is proposed. Species within the Apocreadiinae and Postporinae are reviewed and the following are recorded or described from Australian fishes: Homalometron wrightae n. sp. from Achlyopa nigra (Macleay), H. synagris (Yamaguti, 1953) n. comb. from Scolopsis monogramma (Cuvier), H. stradbrokensis n. sp. from Gerres subfasciatus Cuvier, Marsupioacetabulum opallioderma n. sp. from G. subfasciatus, Neoapocreadium karwarensis (Hafeezullah, 1970) n. comb. from G. subfasciatus, N. splendens n. sp. from S. monogramma and Callohelmis pichelinae n. g., n. sp. from Hemigymnus melapterus (Bloch), H. fasciatus (Bloch), Stethojulis bandanensis (Bleeker) andChoerodon venustus (De Vis). Callohelmis is recognised by the combination of absence of tegumental spines, caeca terminating midway between the testes and posterior end of body, ventral sucker enclosed in a tegumental pouch, prominent muscles radiating through the body from the ventral sucker, vitelline follicles not extending into the forebody, and a very short excretory vesicle that opens ventrally. New combinations for species previously recognised within Crassicutis are proposed as follows: Neoapocreadium caranxi (Bilqees, 1976) n. comb., N. gerridis (Nahhas & Cable, 1964) n. comb., N. imtiazi (Ahmad, 1984) n. comb. and N. marina (Manter, 1947) n. comb. The host-specificity and zoogeography of the Apocreadiinae are considered.

The status of the genera Hysterolecithoides Yamaguti, 1934, Neotheletrum Gibson & Bray, 1979 and Machidatrema Leon-Regagnon, 1998 (Digenea : Hemiuroidea), including a description of M. leonae n. sp from Australian waters

A diagnosis is given for the lecithasterid genus Hysterolecithoides Yamaguti, 1934, which is now found to have two to six (possibly seven) vitelline masses. The species H. frontilatus (Manter, 1969) is returned to the genus, having been considered a member of the bunocotylid genus Neotheletrum by recent authors. It is redescribed from Siganus nebulosus, Moreton Bay, and S. doliatus, Lizard Island, Great Barrier Reef and New Caledonia, with emphasis on the presence of Juel's organ, a uterine seminal receptacle and the blind sac associated with the genital atrium. It differs from its congeners in the trajectory of the pars prostatica which recurves dorsally to the sinus-sac. Oligolecithoides Shen, 1982 is synonymised with Hysterolecithoides and O. trilobatus Shen, 1982 is synomised with H. epinepheli Yamaguti, 1934. Machidatrema Leon-Regagnon, 1998 is diagnosed, and found to be close to Hysterolecithoides, but differs in the lack of a blind-sac projecting from the dorsal genital atrium, by its tandem testes, the coiling of the uterus between the testes and the ovary, and the ventral excretory pore. M. leonae n. sp. is described from Siganus fuscescens, S. lineatus, S. doliatus, S. corallinus, S. vulpinus and Scarus globiceps at Heron Island, Queensland. It differs from its closest congener, M. akeh, in the muscular and tegumental flap over the genital pore and details of the terminal genitalia. M. chilostoma (Machida, 1980) and M. kyphosi (Yamaguti, 1970) are redescribed from Kyphosus vaigiensis from Heron Island. Neotheletrum Gibson & Bray, 1979 is diagnosed: it differs from Hysterolecithoides in its confluent excretory arms, blind seminal receptacle (no Juel's organ) and uniformly tripartite vitellarium. A cladistic analysis suggests that M. chilostoma and M. kyphosi are not best accommodated in Machidatrema, that Machidatrema (sensu stricto) is monophyletic and that Hysterolecithoides is paraphyletic. Hysterolecithoides and Machidatrema are considered hysterolecithine lecithasterids, whilst Neotheletrum is retained as an opisthadenine bunocotylid.

Muscle fibre types and size distribution in sub-antarctic notothenioid fishes

The presumptive tonic muscles fibres of Cottoperca gobio, Champsocephalus esox, Harpagifer bispinis, Eleginops maclovinus, Patagonothen tessellata, P. cornucola and Paranotothenia magellanica stained weakly or were unstained for glycogen, lipid, succinic dehydrogenase (SDHase) and myosin ATPase (mATPase) activity. Slow, intermediate and fast twitch muscle fibres, distinguished on the basis of the pH stability of their mATPases, showed intense, moderate and low staining activity for SDHase, respectively. Slow fibres were the major component of the pectoral fin adductor profundis muscle. The proportion of different muscle fibre types varied from the proximal to distal end of the muscle, but showed relatively little variation between species. The myotomes contained a lateral superficial strip of red muscle composed of presumptive tonic, slow twitch and intermediate fibres, thickening to a major wedge at the horizontal septum. All species also had characteristic secondary dorsal and ventral wedges of red muscle. The relative abundance and localization of muscle fibre types in the red muscle varied between species and with body size in the protandric hermaphrodite E. maclovinus. The frequency distribution of diameters for fast twitch muscle fibres, the major component of deep white muscle, was determined in fish of a range of body sizes. The absence of fibres <20 mu m diameter was used as a criterion for the cessation of muscle fibre recruitment. Fibre recruitment had stopped in P, tessellata of 13.8 cm L-T and E, maclovinus of 32.8 cm L-T, equivalent to 49 and 36.5% of their recorded maximum sizes respectively. As a result in 20-cm P. tessellata, the maximum fibre diameter was 300 mu m and 36% of fibres were in excess of 200 mu m The unusually large maximum fibre diameter, the general arrangement of the red muscle layer and the extreme pH lability of the mATPase of fast twitch fibres are all common characters of the sub-Antarctic and Antarctic Notothenioids, including Cottoperca gobio, the suggested sister group to the Notothenidae. (C) 2000 The Fisheries Society of the British Isles.

The status of Petalocotyle Ozaki, 1934 (Digenea : Gyliauchenidae), including the description of two new species from acanthurid fishes in Queensland, Australia

The status of Petalocotyle Ozaki, 1934 within the Gyliauchenidae Goto & Matsudaira, 1918 is reviewed. Two new species, P. adenometra from Prionurus microlepidotus (Amity Point, Queensland, Australia) and P. diverticulata from Acanthurus nigrofuscus and A. lineatus (Heron Island, Queensland, Australia), are described. The body plan of Petalocotyle conforms to that of members of the Gyliauchenidae (oral sucker absent, well-developed pharynx, complex oesophagus and characteristic male terminal genitalia), indicating justifiable inclusion in this family. A new diagnosis is given for the genus, such that Petalocotyle is now identified by the presence of an anterior, protuberant ventral sucker, long caeca, a large, sigmoid cirrus-sac containing a coiled ejaculatory duct, and an extensive vitellarium. We suggest that, of all the known genera of gyliauchenids, Petalocotyle may most closely resemble the 'archaetypal gyliauchenid', that is, it may be placed basally within the radiation of the Gyliauchenidae. However, derived characters, like diverticula in the reproductive system, indicate that some characters of individual members of Petalocotyle may be considered advanced and do not reflect an archaetypal condition. Parallels in the structure of the male and female genitalia of Robphildollfusium Paggi & Orecchia, 1963 and Petalocotyle, along with the shared morphology of the digestive tract, indicate possible phylogenetic links between the two genera. This affinity is difficult to infer using morphology alone and recommend that Robphildollfusium remain detached from the Gyliauchenidae.

Central projections of Drosophila sensory neurons in the transition from embryo to larva

Sensory axons of different sensory modalities project into typical domains within insect ganglia. Tactile and gustatory axons project into a ventral layer of neuropil and proprioceptive afferents, including chordotonal axone, into an intermediate or dorsal layer. Here, we describe the central projections of sensory neurons in the first instar Drosophila larva, relating them to the projection of the same sensory afferents in the embryo and to sensory afferents of similar type in other insects. Several neurons show marked morphologic changes in their axon terminals in the transition between the embryo and larva. During a short morphogenetic period late in embryogenesis, the axon terminals of the dorsal bipolar dendrite stretch receptor change their shape and their distribution within the neuromere. In the larva, external sense organ neurons (es) project their axons into a ventral layer of neuropil. Chordotonal sensory neurons (ch) project into a slightly more dorsal region that is comparable to their projection in adults. The multiple dendrite (md) neurons show two distinctive classes of projection. One group of md neurons projects into the ventral-most neuropil region, the same region into which es neurons project. Members of this group are related by lineage to es neurons or share a requirement for expression of the same proneural gene during development. Other md neurons project into a more dorsal region. Sensory receptors projecting into dorsal neuropil possibly provide proprioceptive feedback from the periphery to central motorneurons and are candidates for future genetic and cellular analysis of simple neural circuitry. J. Comp. Neurol. 425:34-44, 2000. (C) 2000 Wiley-Liss, Inc.

Venusicola inusitatus gen. n., sp n. (Digenea, Acanthocolpidae) from the Venus tuskfish Choerodon venustus (De Vis) from the southern Great Barrier Reef

The new acanthocolpid genus Venusicola is erected for V. inusitatus sp, n. from the marine tuskfish Choerodon venustus from Heron Island on the southern Great Barrier Reef. This genus is unique in the family in having a greatly elongated ventral sucker with lateral apertural lips and a pavement of blunt spines lining the aperture.

Identifying rate-limiting nodes in large-scale cortical networks for visuospatial processing: an illustration using fMRI

With the advent of functional neuroimaging techniques, in particular functional magnetic resonance imaging (fMRI), we have gained greater insight into the neural correlates of visuospatial function. However, it may not always be easy to identify the cerebral regions most specifically associated with performance on a given task. One approach is to examine the quantitative relationships between regional activation and behavioral performance measures. In the present study, we investigated the functional neuroanatomy of two different visuospatial processing tasks, judgement of line orientation and mental rotation. Twenty-four normal participants were scanned with fMRI using blocked periodic designs for experimental task presentation. Accuracy and reaction time (RT) to each trial of both activation and baseline conditions in each experiment was recorded. Both experiments activated dorsal and ventral visual cortical areas as well as dorsolateral prefrontal cortex. More regionally specific associations with task performance were identified by estimating the association between (sinusoidal) power of functional response and mean RT to the activation condition; a permutation test based on spatial statistics was used for inference. There was significant behavioral-physiological association in right ventral extrastriate cortex for the line orientation task and in bilateral (predominantly right) superior parietal lobule for the mental rotation task. Comparable associations were not found between power of response and RT to the baseline conditions of the tasks. These data suggest that one region in a neurocognitive network may be most strongly associated with behavioral performance and this may be regarded as the computationally least efficient or rate-limiting node of the network.

Scorpidotrema longistipes n. g., n. sp. (Digenea: Opecoelidae) from Scorpis georgiana (Teleostei: Scorpididae) from southern Western Australia

Scorpidotrema longistipes n. g., n. sp. is described from the intestine of Scorpis georgiana Valenciennes (Scorpididae) from off Point Peron, Western Australia. The new genus is distinguished by the combination of a remarkably long and retractable ventral sucker peduncle, a possible uroproct, well-developed cirrus-sac and a uterine seminal receptacle. The subfamilial relationships of the new genus are troublesome. It incorporates features of the Opecoelinae, Stenakrinae and Plagioporinae. The absence of a canalicular seminal receptacle suggests a relationship with the Opecoelinae and Stenakrinae, whereas the well-developed cirrus-sac suggests a relationship with the Plagioporinae and Stenakrinae. The overall arrangement of the gonads is not similar to that of existing genera of Stenakrinae. It is concluded that the genus is best placed in the Stenakrinae although that subfamily may now be an artificial assemblage. This new genus forms part of a distinctive fauna of trematodes restricted to Australian southern temperate fishes.

Response selection deficits in melancholic but not nonmelancholic unipolar major depression

One consistent functional imaging finding from patients with major depression has been abnormality of the anterior cingulate cortex (ACC). Hypoperfusion has been most commonly reported, but some studies suggest relative hyperperfusion is associated with response to somatic treatments. Despite these indications of the possible importance of the ACC in depression there have been relatively few cognitive studies ACC function in patients with major depression. The present study employed a series of reaction time (RT) tasks involving selection with melancholic and nonmelancholic depressed patients, as well as age-matched controls. Fifteen patients with unipolar major depression (7 melancholic, 8 nonmelancholic) and 8 healthy age-matched controls performed a series of response selection tasks (choice RT, spatial Stroop, spatial stimulus-response compatibility (SRC), and a combined Stroop + SRC condition). Reaction time and error data were collected. Melancholic patients were significantly slower than controls on all tasks but were slower than nonmelancholic patients only on the Stroop and Stroop + SRC conditions. Nonmelancholic patients did not differ from the control group on any task. The Stroop task seems crucial in differentiating the two depressive groups, they did not differ on the choice RT or SRC tasks. This may reflect differential task demands, the SRC involved symbolic manipulation that might engage the dorsal ACC and dorsolateral prefrontal cortex (DLPFC) to a greater extent than the, primarily inhibitory, Stroop task which may engage the ventral ACC and orbitofrontal cortex (OFC). This might suggest the melancholic group showed a greater ventral ACC-OFC deficit than the nonmelancholic group, while both groups showed similar dorsal ACC-DLPFC deficit.

Revision of the larval morphology (Zoea I) of the family Hippolytidae (Decapoda, Caridea), with a description of the first stage of the shrimp Hippolyte obliquimanus Dana, 1852

The aim of this study was to summarize the available data on larval morphology of the first zoea of the family Hippolytidae and describe the first zoeal stage of H. obliquimanus from two geographically distinct populations, Brazilian and Caribbean in order to discuss inter- and intraspecific variability. Ovigerous females of Hippolyte obliquimanus were collected at Cahuita (Limon, Costa Rica) and at Ubatuba (Sao Paulo, Brazil). We compiled the published descriptions of all available hippolytid Zoea I (66 spp., 21%), and all zoeae share several characteristics. However, such morphological features cannot be used to distinguish the first zoeae of Hippolytidae from other caridean larvae. Historically, the presence of an exopodal seta at the maxillule and the absence of the anal spine/papilla have been considered as characteristic for the Zoea I of the genus Hippolyte. The results of our revision, however, did not support these conclusions: although H. obliquimanus showed an exopodal seta at the maxillule, four congeners did not bear such structure; moreover, H. obliquimanus as well as one other congener have an anal spine/papilla. All morphological characters observed in the first zoeal stage of H. obliquimanus are shared with others species of the family Hippolytidae. Intraspecific variability in Hippolyte obliquimanus was detected in one morphological aspect: the first zoea had four denticles on the ventral margin of the carapace in the Brazilian population, while specimens from the Costa Rican population had three.