Description of Plerocerci and Adults of a New Species of<i>Grillotia</i>(Cestoda: Trypanorhyncha) in Teleosts and Elasmobranchs From the Patagonian Shelf Off Argentina

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The ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidae) was studied using histochemistry, scanning, and transmission electron microscopy. The central bothridial structure resulted in a glandulomuscular organ formed by a mass of syncytial glands and radial muscles, with glycoprotein secretions potentially adhesive. Among the sensory receptors found on the scolex, a particular type was found surrounding the glandulomuscular organ, which might be related in the regulation of the secretions. The internal structure of the microtriches revealed a diversity of configurations according to their morphotype and distribution on the scolex. Microtriches with larger caps are thought to be useful for attachment purposes. In addition, the thick bounding membranes of the attachment organs and the circular musculature in the bothridia, seem to aid to the attachment of the scolex to the mucosa of the host.

Section: Discussionmentioning

confidence: 99%

Ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidea)

Mutti

Ivanov

2019

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“…Palm () presented a generic diagnosis in which the microtriches were described for the first time. The data on the microtriches of this genus was complemented when Menoret and Ivanov () described the microthrix patterns of Grillotia carvajalregorum and G . patagonica .…”

Section: Discussionmentioning

confidence: 99%

“…Richmond and Caira (1991); 17. Menoret and Ivanov (2012). Abbreviations: A, adult; P, plerocercus; IS, immature specimen.…”

Section: Discussionmentioning

confidence: 99%

“…According to the most recent classification for this order (Palm, 2004), this taxon has five superfamilies, of which the Lacistorhynchoidea Guiart, 1927 consists of two families Pterobothriidae Pintner, 1931 andLacistorhynchidae Guiart, 1927. The second family possesses 17 genera and 61 species (Palm, 2004;Beveridge and Campbell, 2007;Beveridge and Justine, 2007a, b;Menoret and Ivanov, 2009;Beveridge and Campbell, 2010;Beveridge and Campbell, 2012;Menoret and Ivanov, 2012;Beveridge and Campbell, 2013). Of these 61 species, information on the microtriches of 29 species is more or less available (see Table 4).…”

Section: Introductionmentioning

confidence: 99%

“…The data on the microtriches of this genus was complemented when Ivanov (2009, 2012) described the microthrix patterns of Grillotia carvajalregorum and G. patagonica. Although the microtriches of the distal bothrial surface of G. pristiophori Beveridge and Campbell, 2001 called obtuse microtriches by Beveridge and Campbell (2001) were considered as gladiate microtriches by Palm (2004), such structures were considered as columnar spinitriches by Menoret and Ivanov (2012) and were not mentioned in the generic diagnosis (see Palm 2004). Despite the fact that the generic diagnosis must be amended from this view, it needs to be standardised based on Chervy (2009) and completed by additional information.…”

mentioning

confidence: 99%

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

Haseli

Azimi

Valinasab³

2015

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.

Ultrastructure of the rhyncheal apparatus and other structures of the scolex of Grillotia (Christianella) carvajalregorum (Cestoda: Trypanorhyncha)

Mutti

Ivanov

2020

The scolex ultrastructure was studied in Grillotia (Christianella) carvajalregorum (Cestoda: Trypanorhyncha) using histochemistry and transmission electron microscopy. We show for the first time the presence of scolex glands arranged in two longitudinal acini at the pars vaginalis parenchyma. These glands, along with those scattered in bothrial parenchyma, produce potentially adhesive glycoprotein secretions that are discharged via ducts to the bothrial grooves and apex. A particular type of sensory receptor was found around frontal gland pores, with a possible function in regulating their secretion activity. The internal structure of microtriches varies according to their morphotype and distribution on the scolex, this study providing the first description of the ultrastructure of serrate lanceolate spinitriches. The projections that form serrate margins are an extension of the medulla, differing from similar projections of other spinitriches. The large caps observed in serrate lanceolate spinitriches may reflect their specialization in attachment to and abrasion of intestinal mucosa, while the short caps and large bases of acicular filitriches may reflect their involvement in nutrient absorption. We also describe the rhyncheal apparatus ultrastructure, showing a similar basic structure of tentacular walls than that of other trypanorhynchs. Some differences among species in the number of fibrous layers, composition of the apical cytoplasm and presence of microvilli‐like projections were discussed. Finally, our study describes in detail the internal ultrastructure of hollow hooks, evidencing the presence of cytoplasm, mitochondria and fibrils. The location of these fibrils may increase the area of contact surface of hooks on tentacles, possibly allowing for a higher tensile strength than that of solid hooks. We consider that gland location and shape, composition of tentacular wall layers, and hook internal structure may serve as useful characters for the taxonomy and phylogeny of Trypanorhyncha.Research Highlights This is the first description of scolex internal ultrastructure in Grillotia carvajalregorum, showing the presence of glands arranged in two longitudinal acini at the pars vaginalis parenchyma, with potentially adhesive functions. The internal ultrastructure of serrate lanceolate spinitriches and acicular filitriches may reflect their specialization in attachment to the host intestinal mucosa and their involvement in nutrient absorption, respectively. Internally, hollow hooks have cytoplasm with mitochondria and fibrils, which are more widely distributed than in solid hooks, possibly increasing their tensile strength.