Microscopic anatomy and ultrastructure of the male genital system inPorocephalus crotali andP. stilesi (Pentastomida: Porocephalida)

The male genital systemPorocephalus crotali andP. stilesi consists of an unpaired testis, Y-shaped or paired seminal vesicles, paired ejaculatory bulbs (ducts), vasa deferentia, cirri, cirrus sacs, and dilators. Cirri and dilators can travel into the genital atrium. An ultrastructural analysis of each of these components is presented, including sperm development, which has been traced through some important stages. The main differences between the male genital systems of the two subgroups of Pentastomida (Cephalobaenida and Porocephalida) concern the anatomy of the seminal vesicle, the shape and ultrastructure of the ejaculatory bulbs (ducts), the existence of cirrus sacs, the length of the coiled cirrus within the sacs, and the structure of the dilators. However, ultrastructural features reveal homologies between the various components of the male genital systems of cephalobaenids and porocephalids.     

Shape,size and surface topography of genital organs of Leucochloridium sp. (Digenea), revealed by light and scanning electron microscopy

Summary The opening of the genital atrium in Leucochloridium sp. was always situated on the dorsal side near the terminal end, and below the excretory pore common to Laurer's and the excretory canal. The genital pore was surrounded by an aggregation of domed aciliate papillae. Information on the cirrus pouch (position, shape and size) are given. No distinct Vesiculum seminalis was found. A well-developed metraterm empties into right side of genital artium. The cirrus was unarmed and approximately cylindrical. The cirrus surface was covered with anastomosing ridges giving an irregular net-shaped appearance. Papillae with short apical knob were scarcely scattered around on the cirrus surface with increased frequency near cirrus base. The taxonomical value of the genital characters are discussed in relation to corresponding information on the other species of Leucochloridiidae.Abbreviations Used in Figures 1–11 ce caeca end - cp cirrus papillae - cpo cirrus pouch - de ductus ejaculatorius - e egg - ep excretory pore - ga genital atrium - go genital opening - gp genital papillae - ic invaginated cirrus - lco Laurer's canal opening - mo metraterm opening - pt posterior testes - s spine - te terminal end - u uterus - v vitellaria - vd vas deferens - vs ventral side     

<Emphasis Type="Italic">Polylabris bengalensis</Emphasis> sp. nov. (Monogenea,Microcotylidae) from siganid fishes of the Visakhapatnam coast,Bay of Bengal,India

A new species Polylabris bengalensis (Monogenea, Microcotylidae) is described from the gills of the siganid fishes, Siganus javus and S. oramin from the coast of Visakhapatnam, Bay of Bengal, India. It most closely resembles P. mamaevi but differs in having unequal caeca terminating at different levels in the haptor, in the follicular testis forming a compact mass, in the presence of a thick layer of concentric muscles surrounding the genital atrium and in the terminal part of the male copulatory organ not recurved. The validity of various species of Polylabris recorded from siganids from different geographical regions is discussed.     

Renylaima capensis n. gen., n. sp. (Trematoda: Brachylaimidae) from the urinary system of the shrew Myosorex varius Smuts, 1832 (Insectivora: Soricidae)

A trematode species belonging to the family Brachylaimidae was found in the kidneys and ureters of the forest shrew Myosorex varius (Insectivora: Soricidae: Crocidosoricinae) in a restricted, very damp area of the Hottentots Holland Mountain range, near Cape Town, South Africa. The adult stage is described anatomically and histologically. The relative frequency of monotesticular forms is highlighted. A comparison is made with other brachylaimid species known to infect shrews and other peculiar brachylaimids from poikilothermic invertebrates and vertebrates with which the South African species shares several aspects. Peculiar characteristics such as absence of a cirrus pouch and cirrus and presence of a genital atrium that can be evaginated to produce a prominent ventral extention of the body, as well as the fact that the urinary system of a mammal host is an extraordinary microhabitat for a trematode, indicate that this digenean represents a new genus and species for which the name Renylaima capensis n. gen., n. sp. is proposed.     

Two new species of entobdelline skin parasites (Monogenea,Capsalidae) from the blotched fantail ray, <Emphasis Type="Italic">Taeniura meyeni</Emphasis>, in the Pacific Ocean,with comments on spermatophores and the male copulatory apparatus

We made a comparative anatomical study of entobdelline monogenean skin parasites from the blotched fantail ray, Taeniura meyeni (= T. melanospila) from public aquaria and fish-holding facilities distributed widely across the western Pacific Ocean. These facilities were located in Australia (Mooloolaba, southern Queensland; Cairns, northern Queensland), Taiwan and Japan. The capture localities of the aquarium fishes are unknown to us, with the exception of the individual fish from northern Queensland which came from Sudbury Reef, a local inshore reef. Entobdellines from southern Queensland differed morphologically from those from northern Queensland and Taiwan and the 2 new monogenean species are described and named Neoentobdella garneri sp. nov. and N. taiwanensis sp. nov., respectively. We determined that an entobdelline collected by Dyer and co-workers from a ray identified as T. melanospila (= T. meyeni) from an aquarium in Okinawa, Japan and identified by them as Entobdella squamula (Heath, 1902) Johnston, 1929 was misidentified and is tentatively assigned to N. taiwanensis sp. nov. The male copulatory organ of each new species resembles a penis, but evidence that these organs are eversible like a cirrus is presented. Caution is advised in deciding whether the male copulatory organs of capsalids may function as a penis or as a cirrus and we suggest that possession of a penis versus a cirrus may not necessarily indicate wide evolutionary divergence. In N. garneri, spermatophores consist of a sausage-shaped capsule and a long hollow stalk. A spermatophore received from a donor is anchored in the vagina by means of the stalk, with the capsule protruding outside the body.     

An ultrastructural study of the cirrus and vagina ofPhyllobothrium vagans (Cestoda: Tetraphyllidea)

Ultrastructural observations on the genital ducts ofPhyllobothrium vagans revealed that the lining of both cirrus and vagina is made up of a distal cytoplasmic layer, similar to the tegument, and is lined with microtriches. Microtrichial polymorphism was found in the lining of the cirrus. The ultrastructure of the glandular cells surrounding cirrus and vagina, and of the cirrus sac is described. The significance of the findings to earlier studies on microthrix structure and function as well as to early histological studies of the genital ducts of cestodes is discussed.     

Dendromonocotyle urogymni sp. nov. (Monogenea, Monocotylidae) from Urogymnus asperrimus (Elasmobranchii, Dasyatidae) off eastern Australia

Dendromonocotyle urogymni sp. nov. is described from the dorsal surface of the porcupine ray, Urogymnus asperrimus, kept at Cairns Marine Aquarium Fish in Cairns, Queensland, Australia. Dendromonocotyle urogymni can be distinguished most readily from the other 15 species in the genus by the male copulatory organ which has a distinct spherical inflation mid-way along its length. This is the first monocotylid to be described from U. asperrimus.     

Lamellodiscus crampus sp. nov. (Monogenea, Diplectanidae), a parasite of Dentex maroccanus (Teleostei, Sparidae) from off Tunisia

Lamellodiscus crampus sp. nov. (Monogenea, Diplectanidae) is described from the gills of Dentex maroccanus (Valenciennes) collected from the Gulf of Gabès (Tunisia) in the oriental part of Mediterranean Sea. The new species belongs to the “ignoratus” group (sensu Oliver 1987) characterized by a lamellodisc with complete lamellae and a “lyre” shaped male copulatory organ, and the “ignoratus” sensu stricto subgroup, characterized by a haptor with simple lateral dorsal bars, as proposed by Amine and Euzet (2005). Lamellodiscus crampus can be easily distinguished from all the congeneric species of the subgroup “ignoratus” by the presence, in the “lyre” male copulatory organ, of five spines in the distal portion on the axial side of the paired piece.     

Digenean parasites of Cariama cristata (Aves, Gruiformes) from Formosa Province, Argentina, with the description of a new species of the genus Strigea

A new strigeid digenean, Strigea inflecta sp. nov., is described from the small intestine of the Red-legged Seriema, Cariama cristata (L.) (Gruiformes, Cariamidae) from Formosa Province, Argentina. This species is characterized by having a body plump, a cup-shaped forebody with a large opening, a sacciform hindbody, without a neck region and strongly curved dorsally, a poorly delimited copulatory bursa, wider than longer, a shallow and asymmetrical genital atrium, and a genital cone well delimited from body parenchyma, strongly muscular, inclined towards the surface ventral of the body. Another digenean species collected from Red-legged Seriema, Brachylaima yupanquii Freitas, Kohn et Ibá?ez, 1967 (Brachylaimidae) is described with the addition of new morphological characters and morphometrical data. This species is reported for the first time in Argentina and C. cristata represents a new host record.     

Role of androgen in sexual reflexes of the male rat

Studies were conducted on genital reflexes (erections, cups and flips), which occur spontaneously in supine unanesthetized male rats. The androgen dependence of this behavior was first demonstrated by a significant decline in all reflexes after castration. Second, the establishment of stable blood androgen levels by testosterone administration via Silastic capsules resulted in partial or complete maintenance of the reflexes after castration, depending on the dose. The circulating titer of androgen required for reflex performance which resembled that of intact rats was considerably less than the normal mean blood level, as previously found for copulatory behavior. Apart from very low androgen situations, there seems to be no necessary relationship of copulatory behavior performance to reflex responses and the variance in the latter is apparently unrelated to plasma testosterone level in normal intact adults. Nevertheless, the androgen dependence of genital reflexes is an essential component of the normal androgenic regulation of copulatory behavior.     

Involvement of the lateral mesencephalic tegmentum in copulatory behavior of male rats: neuron activity in freely moving animals

Single unit activity was recorded from the lateral mesencephalic tegmentum (LMT) during free copulatory activity by male rats. Twenty-four (89%) of 27 units showed changes in the firing rate during at least one of the three phases of copulatory behavior: pursuit of the female, pelvic thrusting and genital grooming. The activity of 16 units (59%) increased during pursuit of the female, and the activity of 3 units (11%) increased markedly during pelvic thrusting accompanied by intromission. In contrast, 6 units (22%) were suppressed during thrusting with intromission. Whereas the activity of 10 units (37%) increased during genital grooming, 7 units (26%) were suppressed below the baseline during this behavior. The specific firing patterns of the LMT units that are correlated with the particular copulatory movements are a strong indication that the LMT may have an important function in the execution of male copulatory behavior. Some LMT units may mediate sensory information from the genitals that is needed to display a series of copulatory movements. Other units may be more directly related to reflex-like copulatory movements.     

<Emphasis Type="Italic">Heterocotyle tokoloshei</Emphasis> sp. nov. (Monogenea,Monocotylidae) from the gills of <Emphasis Type="Italic">Dasyatis brevicaudata</Emphasis> (Dasyatidae) kept in captivity at Two Oceans Aquarium,Cape Town,South Africa: Description and notes on treatment

Heterocotyle tokoloshei sp. nov. is described from the gills of a single Short-tail stingray, Dasyatis brevicaudata, kept in captivity at the Two Oceans Aquarium in Cape Town, South Africa. The stingray exhibited laboured gill ventilation and deteriorating health on exhibit and was removed to the quarantine area for parasitological study and treatment. A 12 h bath treatment of praziquantel at 20mg/l, pre-dissolved in ethanol, removed 3084 parasites from the gills of the ray. However, the presence of a large number of eggs 24 h post-treatment indicated that viable egg laying adults remained on the gills and that the treatment was not 100% effective. Praziquantel was subsequently administered orally by intubation to the same ray at 150 mg/kg under anaesthetic (2-phenoxyethanol at 0.15 ml/l for approximately 1 h), which resulted in the removal of approximately 392 000 parasites from the gills 12 h post-oral treatment. Twenty-four h post-oral treatment, 3383 worms, but no eggs were recovered. No worms or eggs were recovered 48 h to 10 days post-oral treatment. The ray died approximately 30 days after the completion of the treatment. Heterocotyle tokoloshei sp. nov. is the first Heterocotyle species described from South Africa and represents the first record of a pathogenic Heterocotyle species. The new species can be distinguished from the other 16 species in the genus by the distal region of the male copulatory organ which has distinct small spines and by the morphology of the male copulatory organ accessory piece. Eggs of H. tokoloshei sp. nov. are laid singly and hatch spontaneously between 5 and 8 days at 18°C.     

A new genus and new species of microbothriid monogenean (Platyhelminthes) with a functionally enigmatic reproductive system,parasitic on the skin and mouth lining of the largetooth sawfish, <Emphasis Type="Italic">Pristis microdon</Emphasis>, in Australia

Dermopristis paradoxus gen. et sp. nov., a microbothriid monogenean parasite from the skin and mouth lining of the largetooth sawfish, Pristis microdon (Elasmobranchii, Pristidae) in Australia, is described. The parasite has 2 juxtaposed testes and differs from other microbothriids in possessing a unique and unusual terminal male reproductive tract comprising a proximal and a distal tube, the latter with a conspicuous opening on the ventral surface and lacking a recognisable male copulatory organ. The smalltooth sawfish, P. pectinata, also has a skin-parasitic microbothriid, Dermophthirioides pristidis Cheung et Nigrelli, 1983, but this parasite species has a prominent copulatory papilla. Dermopristis paradoxus also has parallel ridges with broad tops running in a roughly transverse direction across the ventral surface of the body. The ventral ridges are prominent from the level of the pharynx to the posterior region of the body. The function of the ridges is unknown. Reproductive biology, attachment and feeding in D. paradoxus are discussed. In the absence of unmounted parasite specimens for sectioning, a mounted specimen of D. paradoxus was released from the slide and successfully processed to provide serial, stained, resin sections. This useful technique is recommended to provide anatomical information in situations where only specimens on slides are available for study.     

Functional and topographic anatomy of the lymph heart and lymphatic system in the pelvic region of water-fowl and ratite birds

The topography of the lymph system and of the lymph heart can be determined by injections of India ink, Berlin blue, Latex or contrast media. For the direct injection of marker medium into the lymphatic system of adult male birds, the lymphatic copulatory organ was chosen. In embryos and chicks, the foot pads are suited for an indirect injection of marker medium. Following the injections, the marker medium was passed on to the lymph heart via the lymph vessels of the pelvic limbs and by the truncus thoracoabdominalis. Efferent lymph vessels of the lymph heart empty into the pelvic venous system and into the lymphovenous sinus durae matris. The lymphovenous sinus durae matris is also suited for the injections to visualize the lymph heart. The formation of lymph and the course it takes to erect the lymphatic copulatory organ is described.     

The nervous system of Diplostomum pseudospathaceum Niewiadomska, 1984 (Trematoda,Diplostomatidae)

The nervous system of adult Diplostomum pseudospathaceum Niewiadomska, 1984 was studied using Koelle's (1951) method for revealing cholinesterase activity. The nervous system in the fore body grows but its pattern remains the same as in the metacercaria: three pairs of stems connected by numerous commissures and differentiated innervation of various organs in this part of the body. In the elongated hind body the nervous system develops according to another pattern: two pairs of stems connected by a number of commissures form a loose net surrounding the whole segment. The net is more dense at the body end around the genital opening and copulatory organs. A brief discussion of the development of the nervous system of D. pseudospathaceum from cercaria to adult stage is given.     

Annulotrema (Monogenea: Dactylogyridae) from Hydrocynus brevis (Characiformes: Alestidae) in Senegal,with descriptions of two new species and remarks on Annulotrema pikei

Two new species of Annulotrema Paperna & Thurston, 1969 were collected from the gills of the African tiger fish, Hydrocynus brevis, from the Gambia River basin in the Niokolo-Koba National Park, Senegal. Annulotrema besalis n. sp. is characterized by having a male copulatory organ (MCO) composed of an arcuate copulatory tube articulated to an eight-shaped accessory piece with terminal claw. The new species resembles Annulotrema pikei (Price, Peebles & Bamford, 1969) in having morphologically similar types of haptoral sclerites and MCO. As a result of the differential diagnosis made for A. besalis n. sp., new information on taxonomically important features of A. pikei is provided based on illustrations of the sclerotized parts of the holotype from Hydrocynus vittatus. The report of A. pikei on the gills of Hydrocynus forskahlii by Paperna in 1979 is shown to be erroneous. Annulotrema uncata n. sp. is similar to Annulotrema alestesimberi Paperna, 1973 in its possession of a coiled copulatory tube with about two and a half rings. Features distinguishing the new species include the sharply curved shaft of the ventral anchor, the base of the copulatory tube extending to a sock-like structure and a leech-shaped vagina. The necessity of emending the generic diagnosis of Annulotrema is briefly discussed.     

An ontogenetic study of the cholinergic and serotoninergic nervous systems inTrilocularia acanthiaevulgaris (Cestoda,Tetraphyllidea)

The localisation and distribution of the cholinergic and serotoninergic components of the nervous system in the plerocercoid, adult and free proglottis stages of the tetraphyllidean tapewormTrilocularia acanthiaevulgaris were determined by enzyme histochemical and immunocytochemical techniques. The central nerve ring (CNR) in the scolex contains two lateral ganglia and gives rise to five pairs of longitudinal nerve cords (LNC's; three lateral, two median). The nerve cords run posteriorly throughout the bodies of the plerocercoid and adult worms and the free proglottis. Nerves from the CNR and accessory lateral LNC's pass to the bothridia, where they give rise to extensive nerve plexuses. As the individual proglottides develop along the strobila, a small nerve ring forms at the anterior end of each proglottis; within the nerve ring, distinct bilateral ganglia develop prior to the release of the proglottis. All ten LNC's are present in the free proglottis. The genital atrium and cirrus sac are innervated by cholinergic and serotoninergic elements. The cholinergic nervous system predominates in the CNS within the scolex, whereas there is a larger population of 5-HT-immunoreactive nerve cells associated with the LNC's and segmental ganglia along the strobila and within the free proglottis.     

A new species of Sciadicleithrum (Monogenea, Dactylogyridae) parasitic on Geophagus brasiliensis (Perciformes, Cichlidae) from Guandu River, Southeastern Brazil

Sciadicleithrum guanduensis sp. nov. is described from the gills of the cichlid fish Geophagus brasiliensis (Quoy et Gaimard, 1824) from Guandu River, Seropédica, Rio de Janeiro, Brazil. The new species differs from all congeners by the accessory piece of the male copulatory organ, which comprises a small, delicate sheath with articulated appearance, and by the presence of a large unique umbelliform membrane on the ventral bar.     

Shape,size, and surface topography of genital organs of Urogonimus macrostomus (Rudolphi, 1803) Monticelli, 1888 (Digenea), revealed by light and scanning electron microscopy

Summary The genital apparatus of Urogonimus macrostomus (Rudolphi, 1803) has been studied by SEM and light microscopy. The distinct muscular seminal vesicle and metraterm, cirrus and cirrus pouch, together with uterus and gonadal arrangement are described. The situation of the genital, excretory and Laurer's canal openings are revealed by SEM, beside the tegumental topography concerning spine and papillae distribution at the posterior end. The present results are compared with previous studies on Urogonimus Monticelli, 1888 and Leucochloridium Carus, 1835 (sensu Kagan, 1952) species.