Microthrix pattern of Pseudogilquinia thomasi (Palm, 2000) (Cestoda: Trypanorhyncha) and a review of surface ultrastructure within the family Lacistorhynchidae Guiart, 1927

The microthrix pattern of larvae of Pseudogilquinia thomasi (Palm, 2000) is described for the first time using scanning electron microscopy. The surface ultrastructure of this species consists of three main forms of microtriches: papilliform filitriches, acicular filitriches and quadridigitate to octadigitate palmate spinitriches. The bothria are covered with palmate spinitriches interspersed on some parts with papilliform filitriches. Palmate spinitriches with papilliform, acicular and capilliform filitriches adorn the pars vaginalis and at the anterior part of the pars bulbosa, there is a transition zone in which the palmate spinitriches are replaced by papilliform to acicular filitriches towards the end of the scolex. ANOVA tests with Duncan's post hoc analyses revealed that there are significant differences in the length of spinitriches and their prongs, whether on the surfaces of the bothria or on the surfaces of the scolex peduncle. Callitetrarhynchus gracilis Pintner, 1931 is the second lacistorhynchid species for which surfaces of the segments were examined and the occurrence of large structures called scutes are reported for the first time from this species. There were also significant differences in the base length as well as height of the scutes in different parts of the strobila. In addition to describing the surface ultrastructures of the two lacistorhynchid species, all the available information on the microtriches within the family Lacistorhynchidae is reviewed herein and generic diagnoses related to microtriches are amended. J. Morphol. 277:394–404, 2016. © 2015 Wiley Periodicals, Inc.     

Microtriches of tetraphyllidean metacestodes from Western Mediterranean striped dolphins (Stenella coeruleoalba)

The tegumental structures of two types of tetraphyllidean plerocercoids and two types of merocercoids (Phyllobothrium delphini and Monorygma grimaldii) from Mediterranean striped dolphins, Stenella coeruleoalba, are described for the first time using scanning electron microscopy. The tegument of all of the specimens was fully covered with microtriches. Four basic types were found: filitriches, blade-like spinitriches of different sizes and shapes, cone-shaped spinitriches (with two parallel small projections of equal length at the apex), and crowned cylindrical spinitriches (with 6-7 small papillae forming a crown at the apex); the two latter types are newly described. The two types of plerocercoids had a similar morphology and distribution of microtriches; in addition, cilium-like projections appeared interspersed among the microtriches on the apical sucker, accessory suckers, and distal bothridial loculus. Merocercoids exhibited a greater variety of tegumental structures, especially on the distal bothridial loculus. Both merocercoid types had regularly spaced papillae or "buttons" on the accessory suckers and the distal bothridial loculus that were composed of a central cilium-like projection surrounded by numerous filitriches. However, crowned cylindrical spinitriches were specific to P. delphini and cone-shaped spinitriches were specific to M. grimaldii. Differences in the morphology and distribution of scolex microtriches of adult cestodes have been considered useful for species identification. A previous molecular study has suggested that P. delphini and M. grimaldii are actually different congeneric species. Our study has shown that significant differences in the morphology and distribution of microtriches occur between these species at the merocercoid stage.     

Surface ultrastructure of the elasmobranchia parasitizing <Emphasis Type="Italic">Grillotiella exilis</Emphasis> and <Emphasis Type="Italic">Pseudonybelinia odontacantha</Emphasis> (Trypanorhyncha,Cestoda)

The surface ultrastructure of two monotypic trypanorhynch genera is described based on new material of Grillotiella exilis (Linton, 1909) and type material of Pseudonybelinia odontacantha Dollfus 1966. In G. exilis, spiniform microtriches cover the bothrial surfaces and the anterior part of the pars vaginalis posterior to the bothria. Bifurcate microtriches adorn the bothrial margins, filiform microtriches the scolex peduncle, and capilliform microtriches the posterior scolex end. This microthrix pattern resembles that found in, e.g., Grillotia erinaceus (van Beneden, 1858), with the difference that the anterior part of the pars vaginalis is covered with a collar of multidigitate palmate microtriches. The position of Grillotiella within the Grillotiinae, Lacistorhynchidae is supported based on these data. The bothria and scolex peduncle of P. odontacantha are covered with acerosate and unciniform microtriches on the distal bothrial surface and capilliform microtriches on the scolex peduncle. Short filiform microtriches cover the appendix. The microthrix pattern resembles that of the Tentaculariidae but with unciniform and acerosate microtriches densely covering the entire distal bothrial surface. Tegumental grooves are present on the posterior bothrial margin. They can be distinguished from bothrial pits in otobothrioid trypanorhynchs in having similar unciniform microtriches compared to the other parts of the bothrial surface and in lacking any spiniform microtriches. With the absence of bothrial pits as characteristic for the otobothrioids and its characteristic microthrix pattern, P. odontacantha together with Paranybelinia otobothrioides Dollfus 1966, both belonging to the Paranybeliniidae change their position in the most recent system from the Otobothrioidea into the Tentacularioidea.     

Comparison of microthrix ultrastructure and morphology on the plerocercoid and adult scolex of Calliobothrium cf. verticillatum (Tetraphyllidea: Onchobothriidae)

The distal bothridial surfaces of adult triloculate onchobothriids are covered with short structures that have been tentatively classified as very short filitriches, but this hypothesis has never been tested. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate microthrix morphology in the plerocercoid and adult forms of Calliobothrium cf. verticillatum, a triloculate onchobothriid tapeworm from Long Island Sound (Connecticut). Plerocercoids of C. cf. verticillatum were collected from the anterior midgut ceaca of Pagurus pollicaris Say, 1817 (flat-clawed hermit crab), and adults were collected from the spiral intestine of the dusky smooth hound Mustelis canis (Mitchell, 1815). Two plerocercoids and 2 adults were examined using SEM; 2 plerocercoids and 2 adults were examined using TEM. Microthrix distribution and morphology (including measurements of total length, base length, shaft length, and base width) were investigated on all surfaces of the plerocercoid and adult scolex. Slender filitriches and large bladelike spinitriches were observed extending from the tegument of plerocercoid and adult forms. The filitriches were found to have significantly narrower bases than the spinitriches (65-167 nm vs. 466-1,936 nm, respectively). The scolex proper of the plerocercoid and adult forms were found to have filitriches of medium-length and bladelike spinitriches. The distal bothridial surfaces differed dramatically in microthrix morphology between plerocercoid and adult forms; on the distal surfaces of the plerocercoids were long filitriches and bladelike spinitriches. However, the distal surfaces of the adults had short structures (previously hypothesized to be short filitriches) and a few bladelike spinitriches. Serial transverse sections revealed that the short structures on the distal bothridial surfaces of the adults were homologous with filitriches. They included all of the structural components of a filithrix as well as a base width that conformed to the filitriches found on other surfaces. The bothridial margins of the plerocercoid and adult forms had a microthrix pattern similar to that seen on the proximal bothridial surfaces except that the filitriches on the margins were significantly longer than those found anywhere else on the bothridia. The most dramatic difference between the plerocercoid and adult forms occurred on the distal bothridial surfaces, where the filitriches of the adult cestodes were significantly shorter and narrower, and the spinitriches were almost entirely lacking.     

A new genus and two new species of Aporhynchidae (Cestoda: Trypanorhyncha) from catsharks (Carcharhiniformes: Scyliorhinidae) off Taiwan

New collections of cestodes from the spiral intestines of catsharks (Carcharhiniformes: Scyliorhinidae) off Taiwan have led to the discovery of a new genus and 2 new species of trypanorhynchs. These taxa are relatively unique among trypanorhynchs in their lack of all elements of the rhyncheal apparatus. The new genus, Nakayacestus n. gen., is considered to belong with Aporhynchus in the Aporhynchidae. In addition to lacking the rhyncheal apparatus, these 2 genera share circum-medullary vitelline follicles, post-ovarian testes, and complex terminal genitalia consisting of accessory, external, and internal seminal vesicles. The 2 genera differ conspicuously in spinithrix configuration; whereas both species of Nakayacestus n. gen. bear scolex spinitriches that are bifid, trifid, or pectinate, species of Aporhynchus either lack scolex spinitriches entirely or possess spathulate spinitriches. The configuration of the bothria of the 2 genera also differ conspicuously. Whereas the bothria of Aporhynchus are sessile and generally do not extend beyond the lateral margins of the cephalic peduncle, those of Nakayacestus bear only a tenuous connection with the scolex proper, being conspicuously free both anteriorly and posteriorly and extending conspicuously beyond the cephalic peduncle. Futhermore, the boundary between the scolex and the strobila of members of the new genus is clearly delineated, whereas this distinction is ill-defined in species of Aporhynchus. Nakayacestus takahashii n. sp., the type of the new genus, was collected from the Broadmouth catshark, Apristurus macrostomus, and differs from Nakayacestus tanyderus n. sp., collected from the Blacktip sawtail catshark, Galeus sauteri, in being shorter, bearing a longer pedunculus scolecis, an ovary that is more posterior in the proglottid, and fewer post-ovarian testes. Furthermore, the 2 new species differ conspicuously from one another in the configuration of their scolex spinitriches.     

Morphological evidence that the molecularly determined Ciona intestinalis type A and type B are different species: Ciona robusta and Ciona intestinalis

Ciona intestinalis is considered a widespread and easily recognizable tunicate, the sister group of vertebrates. In recent years, molecular studies suggested that C. intestinalis includes at least two cryptic species, named ‘type A’ and ‘type B’, morphologically indistinguishable. It is dramatic to certify that two different species may be hidden under the name of a species widely used as a model species in biological researches. This raised the problem of identifying diagnostic morphological characters capable of distinguishing these types. We compared the morphology of specimens belonging to the two types and found that only type A specimens possess tunic tubercular prominences, allowing unambiguous discrimination. Remarkably, these structures were already described as distinctive of the Japanese species Ciona robusta, Hoshino and Tokioka, 1967; later synonymized under C. intestinalis (sensu Millar, 1953). In this study, we have confirmed that C. intestinalis type A corresponds to C. robusta. Based on the geographic distribution of C. intestinalis type B, and considering that the original C. intestinalis species was described from North European waters, we determined that C. intestinalis type B corresponds to C. intestinalis as described by Millar in 1953 and possibly to Linnaeus' Ascidia intestinalis L., 1767 for which we have deposited a neotype (from Roscoff, France) and for which we retain the name Ciona intestinalis (Linnaeus, 1767).     

Nomimoscolex semenasae n sp (proteocephalidea: Monticelliidae), a cestode parasite of Diplomystes viedmensis (Pisces: Siluriformes) from the Patagonian region of Argentina

Nomimoscolex semenasae n. sp. is described from the primitive fish Diplomystes viedmensis (Siluriformes) from the Patagonian region of Argentina. The new species is placed in Nomimoscolex because of the cortical position of the vitelline follicles, medullary position of the testes, ovary and uterus, and having a scolex with four uniloculate suckers. N. semenasae differs from all other species in the genus by the following combination of characters: (1) apical organ absent; (2) strobila acraspedote; (3) vagina anterior or posterior to cirrus-sac and lacking a sphincter; (4) testes in one irregular layer and in two fields connected anteriorly; (5) uterine stem cortical in immature proglottides, growing from cortical stem into medullary region in mature proglottides; (6) long uteroduct; and (7) presence of spiniform microtriches on all regions of the scolex, proliferation zone and immature proglottis. This is the first record of a proteocephalidean tapeworm in D. viedmensis and in the family Diplomystidae.     

Histopathological and ultrastructural studies of the tapeworm Monobothrium wageneri (Caryophyllidea) in the intestinal tract of tench Tinca tinca

Monobothrium wageneri is a monozoic caryophyllidean tapeworm of tench Tinca tinca. The pathological changes caused by this parasite within the intestinal tract of wild tench are described for the first time. Parasites were found attached to the anterior third of the intestine in tight clusters comprising up to 109 tapeworms. Infection was associated with the formation of raised inflammatory swellings surrounding the parasites. This host response, combined with the deep penetration of the scolex into the gut wall, formed a very firm seat of parasite attachment. Histopathological changes were characterised by a pronounced fibrogranulomatous lesion that extended through all layers of the intestine. This was accompanied by haemorrhage, oedema, necrosis and degeneration of the muscularis. A marked eosinophilic interface layer between the scolex of the tapeworm and gut wall indicated intimate host-parasite contact. Ultrastructural examinations revealed coniform spinitriches covering the neck and lateral sides of the scolex and capilliform filitriches present on the apical end of the scolex. Numerous glandular cytons (tegumental glands) were recorded throughout the scolex tegument. Large numbers of secretory granules discharged from the glands through a network of processes onto the scolex surface were consistent with distancing the cellular responses of the host. Observations of severe inflammatory lesions, partial intestinal occlusion and the potential for intestinal perforation represent important pathological changes that are consistent with loss of normal gut function. The lesions associated with the attachment of M. wageneri are more severe than those recorded for any other tapeworm of British freshwater fish.     

Ultrastructure of the tegument of the cestode Paraechinophallus japonicus (Bothriocephalidea: Echinophallidae), a parasite of the bathypelagic fish Psenopsis anomala

Abstract. The ultrastructure of the tegument in Paraechinophallus japonicus (Bothriocephalidea: Echinophallidae), a cestode parasite of the bathypelagic fish Psenopsis anomala , was studied using scanning and transmission electron microscopy. Paraechinophallus japonicus lacks a true scolex. Four different types of microtriches have been observed on the tegumental surface of P. japonicus. Capilliform (∼2.3-μm long) and blade-like spiniform (∼1.4-μm long) microtriches are intermingled on the surface of the pseudoscolex. Capilliform microtriches are distinct in possessing a short base and a long electron-lucent cap. The strobila is covered with two types of microtriches, namely filiform (∼2.1-μm long) and tusk-shaped microtriches (≤4.5-μm long). Tusk-shaped microtriches are limited to the posterior border of each proglottid and are characterized by a short and narrow base, and a large and wide, sharply pointed, electron-dense cap. Similar tusk-shaped microtriches were previously found in members of the family Echinophallidae and may represent an autapomorphy of echinophallid cestodes, all of them being parasitic in centrolophid fish. A unified terminology of microthrix parts is proposed.     

A study of the microtriches of adult Echinococcus granulosus by scanning electron microscopy

Thompson R. C. A., Houghton A. and Zaman V. 1982. A study of the microtriches of adult Echinococcus granulosus by scanning electron microscopy. International Journal for Parasitology12: 579–583. The microtriches in different regions of the scolex and strobila of sexually mature Echinococcus granulosus were examined using the scanning electron microscope. E. granulosus was found to possess two morphologically distinct types of microthrix. A cylindrical, slender filamentous type of microthrix which appeared to be flexible was restricted to the scolex. On the strobila, the only type of microthrix observed was a flattened blade-like form which appeared to be rigid for most of its length. The occurrence of two distinct types of microthrix in separate regions of the body of E. granulosus suggests that they may be involved in different functional activities.     

Orygmatobothrium spp. (Cestoda: Tetraphyllidea) from triakid sharks in Argentina: redescription of Orygmatobothrium schmitti and description of a new species

Two species of Orygmatobothrium were found inhabiting triakid sharks collected from the coast of Buenos Aires Province, Argentina. Orygmatobothrium schmittii from Mustelus schmitti is redescribed, including new information on the microtrich pattern. Orygmatobothrium juani n. sp. from Mustelus fasciatus can be distinguished from all other species in the genus using the following combination of characters: worm length, number of proglottids, number of testes, testes distribution, size of eggs, ornamented egg shell, shape of bothridial cleft at level of the marginal accessory sucker, and the extension of vitelline follicles. Species in Orygmatobothrium share a common microtrich pattern with the distal bothridial surface covered with maisiform microtriches interspersed with filiform microtriches, a proximal bothridial surface covered with trifid microtriches, with a medial projection conspicuously larger than the lateral basal projections interspersed with filiform microtriches, an inner and outer surface of the accessory sucker and glandulomuscular organ covered with short filiform microtriches, the scolex proper and cephalic peduncle surface covered with bladelike microtriches, and the germinative zone and entire strobila covered with scutes formed by densely packed filiform microtriches. This general configuration is basically similar to the microtrich pattern described in species of Orectolobicestus and Paraorygmatobothrium.     

Prevalence and Genotyping of Microsporidian Parasites in Dogs in Turkey: Zoonotic Concerns

Microsporidia are opportunistic pathogens that infect a wide range of invertebrates and vertebrates. To assess the potential role of dogs in the transmission of these zoonotic pathogens, a total of 282 fecal samples from dogs in the Central Anatolia Region of Turkey were analyzed by utilizing species specific polymerase chain reaction for the four most frequent human microsporidia. Two microsporidia species were recognized in 41 samples (14.5%). Encephalitozoon intestinalis was detected in 35 samples (12.4%) and it was the most common microsporidium. The second microsporidium, E. cuniculi, was identified in six (2.1%) of the samples. Sequence analysis of the intergenic spacer of the ribosomal ribonucleic acid (RNA) internal transcribed spacer (ITS) gene revealed the presence of three E. intestinalis haplotypes closely associated with each other. No polymorphic region was found among the ITS sequences of E. cuniculi isolates and they were characterized as genotype III. This study provides the first data on the zoonotic microsporidia species from dogs in Turkey.     

A Comparative and Phylogenetic Study of the Ditylenchus dipsaci,Ditylenchus destructor and Ditylenchus gigas Populations Occurring in Poland

The genus Ditylenchus contains more than 80 recognized nematode species with a very wide host range. The most serious species are Ditylenchus dipsaci and Ditylenchus destructor. Populations of D. dipsaci species complex were collected from Allium cepa, Cichorium endivia and Phlox paniculata in Poland. The Ditylenchus gigas population was collected from Vicia faba minor, and populations of D. destructor, from Solanum tuberosum spp. tuberosum. Analyses of the rDNA sequences spanning both ITS1 and ITS2 fragment regions were carried out on the collected populations. The obtained DNA sequences were compared with those DNA sequences deposited in GenBank of populations isolated in other countries. Phylogenetic analysis was performed using the data obtained from the DNA sequence comparisons. The results indicated that there is no clear distinction between European and non‐European populations within D. dipsaci. The results also showed no clear distinction between populations isolated from different host plant species, including populations found in Poland. The populations of D. destructor described here constitute a common group together with American and Chinese populations belonging to the haplotype C of the D. destructor species. On the other hand, the D. gigas population was localized separately from those populations that have been described up until now, from Europe and Africa. This is also the first report on the occurrence of D. gigas in Poland.     

Two new species of Echinobothrium (Cestoidea: Diphyllidea) from myliobatiform elasmobranchs in the Gulf of California, México

Two new species of diphyllidean cestodes, Echinobothrium mexicanum n. sp., and Echinobothrium fautleyae n. sp., are described, the former from the spiral intestines of the bat rays Myliobatis californicus and Myliobatis longirostris and the latter from the spiral intestine of the cownose ray Rhinoptera steindachneri, all caught in the Gulf of California, México. Echinobothrium mexicanum is most easily distinguished from the majority of the species of the genus by the number of large apical hooks in each dorsoventral group (23) and from the remainder in the number of lateral hooklets in each group on the scolex. Echinobothrium fautleyae differs conspicuously from all other members of the genus in that the first and last lateral hooklets in each group are distinctly larger than the other hooklets in each group. Serial sections of the scoleces of these 2 new species confirm that the attachment structures on the scolex are bothria, rather than bothridia, as has been described in other species in the genus, suggesting that the attachment structures of the scolex should be examined in more detail in the genus in general. Palmate microtriches of various forms cover the proximal bothrial surfaces of both new species and are also found on the dorsal bothrial surfaces of E. fautleyae. The distal bothrial surfaces of E. mexicanum are covered with slender spiniform and short filiform microtriches. The cephalic peduncles of both species possess short filiform microtriches only. Comparison of these 2 new species with the other 3 species in this genus that have been examined with SEM suggests that the various forms and distributions of these microtriches is unique in each of these 2 species. We believe these features will prove to be taxonomically useful.     

Ultrastructure of the cirrus sac of echinophallid tapeworms (Cestoda, Bothriocephalidea) and the terminology of cirrus hard structures

Transmission (TEM) and scanning (SEM) electron microscope methods were used to study the fine structure of the cirrus, cirrus sac, internal seminal vesicle, ejaculatory duct, prostate glands and cirrus armature of Echinophallus wageneri (Monticelli, 1890) and Paraechinophallus japonicus (Yamaguti, 1934) (Bothriocephallidea: Echinophallidae). The cirrus sac of these species has two unique ultrastructural features: a thick wall with two bands of muscles and prominent, rooted hard structures. Rare traits echinophallids share with diphyllobothriideans are microtriches on the ejaculatory duct and with spathebothriideans, well-developed unicellular prostate glands outside the cirrus sac. Because there is a similarity of cirrus armature and rostellar hooks in having a tegumental localisation and in having a heterogenous structure of the blade and root, a cortex, a central pulp region and a recurved apex, these structures are named “modified hooks” instead of spines. They also have a spiral arrangement; no base plate was observed. True spines, as found in trematodes, are between the surface and basal plasma membrane of the external syncytial layer of the tegument, rest on the basal plasma membrane of the distal epithelial cytoplasm, show a homogeneous electron-dark crystalline appearance and are covered by the surface plasma membrane. Aside from the characteristic hooks on the scolex of various cestodes, we see no evidence that would preclude the development of still other specialised structures, such as these modified hooks, from microtriches. In spite of the absence of studies on the development of modified hooks from the cirrus of echinophallids and/or its consideration as derived from microtriches, we assume that like microtriches, formation of modified hooks is from tegumental bodies and therefore they are derivative structures of the cestode tegument.     

Convergence beyond flower morphology? Reproductive biology of hummingbird‐pollinated plants in the Brazilian Cerrado

Convergent reproductive traits in non‐related plants may be the result of similar environmental conditions and/or specialised interactions with pollinators. Here, we documented the pollination and reproductive biology of Bionia coriacea (Fabaceae), Esterhazya splendida (Orobanchaceae) and Ananas ananassoides (Bromeliaceae) as case studies in the context of hummingbird pollination in Cerrado, the Neotropical savanna of Central South America. We combined our results with a survey of hummingbird pollination studies in the region to investigate the recently suggested association of hummingbird pollination and self‐compatibility. Plant species studied here differed in their specialisation for ornithophily, from more generalist A. ananassoides to somewhat specialist B. coriacea and E. splendida. This continuum of specialisation in floral traits also translated into floral visitor composition. Amazilia fimbriata was the most frequent pollinator for all species, and the differences in floral display and nectar energy availability among plant species affect hummingbirds' behaviour. Most of the hummingbird‐pollinated Cerrado plants (60.0%, n = 20), including those studied here, were self‐incompatible, in contrast to other biomes in the Neotropics. Association to more generalist, often territorial, hummingbirds, and resulting reduced pollen flow in open savanna areas may explain predominance of self‐incompatibility. But it is possible that mating system is more associated with the predominance of woody hummingbird plants in the Cerrado plant assemblage than to the pollination system itself.     

The helminth parasites of the lesser flamingo,Phoeniconaias minor (Geoffroy), from Lake Nakuru,Kenya, including a new cestode,Phoenicolepis nakurensis n.g., n.sp.

Summary Seven species of cestodes and two of nematodes are reported from Phoeniconaias minor from Lake Nakuru, Kenya. Phoenicolepis nakurensis n.g., n.sp. (Hymenolepididae) is characterized by the size and shape of the hooks, scolex and strobila, structure of the terminal genital ducts, presence of an accessory sac, external seminal vesicle and stylet, and absence of an internal seminal vesicle. Gynandrotaenia stammeri. Cladogynia phoeniconaiadis, Flamingolepis tengizi, F. dolguschini and Striatofilaria phoenicopteri are redescribed; all except C. phoeniconaiadis are new for this host and for Kenya. ac]19800210Abbreviations as accessory sac - c cirrus - cs cirrus sac - esv external seminal vesicle - g gland cells - gs glandular sheath - isv internal seminal vesicle - md muscular duct - Mg Mehlis' gland - o ovary - pg prostate gland cells - s stylet - sr seminal receptacle - u uterus - v vagina - vd vas deferens - vg vitelline gland