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Start Over Subject Cestoda Subject ultrastructure Type TEXT Type model:internalpart

1. Nybelinia queenslandensis sp. n. (Cestoda: Trypanorhyncha) parasitic in Carcharhinus melanopterus, from Australia, with observations on the fine structure of the scolex including the rhyncheal system

Creator:
Jones, Malcolm K. and Beveridge, Ian
Format:
print
Type:
model:internalpart and TEXT
Subject:
Cestoda, Trypanorhyncha, Tenlaculariidae, Nybelinia, morphology, scolex, ultrastructure, tentacles, and taxonomy
Language:
English
Description:
A new species of Nybelinia Poche, 1926, N. queenslandensis sp. n. (Cestoda: Trypanorhyncha) is described from sharks, Carcharhinus melanopterus (Quoy et Gaimard, 1824) from the coast of northeastern Queensland, Australia. Morphological features of the 46 known species of Nybelinia Poche, 1926 are tabulated and the new species is differentiated from all known taxa that are adequately described on the basis of having a homcomorphous armature, metabasal hooks 20-25 pm long, tentacles 0.07-0.09 mm in diameter, short bulbs (0.38-0.45 mm) and craspedote segments with the testes encircling the female genital complex. The fine structure of the scolex microtriches, frontal and rhynchodeal glands, tentacles and hooks, sheath and retractor muscle is described and compared with that of other trypanorhynchs.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Ultrastructure of spermiogenesis of Phyllobothrium lactuca (Cestoda, Tctraphyllidea, Phyllobothriidae)

Creator:
Séne, Aminata, Ba, Cheikh Tidiane, and Marchand, Bernard
Format:
print
Type:
model:internalpart and TEXT
Subject:
ultrastructure, Phyllobothrium, Cestoda, Tetraphyllidea, and spermiogenesis
Language:
English
Description:
Spermiogenesis in Phyllobothrium lactuca Beneden, 1850 begins with the formation of a differentiation zone bordered by cortical microtubules and containing a nucleus and two ccntrioles separated by an intercentriolar body and disposed one in the prolongation of the other. Later, formation of flagellar buds, striated roots and a median cytoplasmic extension takes place. Each centriole gives rise to a flagellimi that rotates and fuses with the median cytoplasmic extension. At this stage, arched membranes appear at the front of the differentiation zone. The nucleus elongates, becomes filiform and migrates between the striated roots into the spermatid. After the migration of the nucleus, the old spermatid separates from the residual cytoplasm by strangulation of the ring of arched membranes. Absence of striated roots, right at the beginning of spermiogenesis has never been described before in the Tctraphyllidea. Likewise, centrioles made up of doublets of microtubules and spermatids with two axonemes have never been reported before during spermiogenesis of a Phyllobothriidae. In this work we show, for the first time, the existence in cestodes of thick-walled microtubulcs surrounded by a layer of electron-dense material. In addition, we describe, for the first time, the existence of an accumulation of electron-dense granules around striated roots and an hour-glass-shaped constriction at the anterior extremity of a median cytoplasmic extension in a platyhelminth.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Ultrastructure of the scolex, rhyncheal system and bothridial pits of Otobothrium mugilis (Cestoda: Trypanorhyncha)

Creator:
Jones, Malcolm K.
Format:
print
Type:
model:internalpart and TEXT
Subject:
Cestoda, ultrastructure, rhyncheal system, scolex, and Trypanorhyncha
Language:
English
Description:
The ultrastructure of the scolex tegument, bothridial pits (“ciliated pits) and rhyncheal system of Otobothrium mugilis Hiscock, 1954 is described from plerocerci collected from the teleosts Arius graeffei Kncr ct Steindachner and Mugil cephalus Linnaeus. Scanning electron microscopy revealed that filamentous microtriches with shortened caps are abundant across the entire surface of the tegument. Palmate microtriches are dominant on the bothridia and their margins. The surfaces of bothridial pits were covered with large bifid microtrichcs. The bothridial pits arc strongly muscularised invaginations of the tegument. Nervous tissues were not observed within the pits and it is probable that these structures function as accessory attachment structures. The wall of each tentacle sheath consists of one to three bands of fibrils, lined internally by a thin cytoplasmic layer. The tentacular walls are cellular, containing myofilaments. The fibrils of the tentacular walls are arranged into discrete blocks of parallel fibrils and appear to be intracellular. Tentacular walls are lined externally by a modified membrane with an external glycocalyx. Tentacular hooks arc solid, bound externally by a membrane. The body of the hook contains numerous longitudinal canaliculi and an elcctron-opaquc medulla lies at the centre of the hook.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public