Interrelationships and Evolution of the Tapeworms (Platyhelminthes: Cestoda)

Olson, Peter D.; Littlewood, D. Timothy J.; Bray, Rodney A.; Mariaux, Jean

doi:10.1006/mpev.2001.0930

Cited by 285 publications

(209 citation statements)

References 52 publications

(103 reference statements)

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“…The intercentriolar body is a character used in phylogenetic studies for the classification of higher-level cestodes (Hoberg et al 1997;Justine 2001;Olson et al 2001;Levron et al 2010). The intercentriolar body in C. crassiceps includes three electron-dense layers delimited by four electron-lucent layers.…”

Section: Spermiogenesismentioning

confidence: 99%

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Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

et al. 2011

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Spermiogenesis and the ultrastructure of the spermatozoon of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Linnaeus, 1758), have been studied by means of transmission electron microscopy. Spermiogenesis involves firstly the formation of a differentiation zone. It is characterized by the presence of two centrioles associated with striated rootlets, an intercentriolar body and an electron-dense material in the apical region of this zone. Later, two flagella develop from the centrioles, growing orthogonally in relation to the median cytoplasmic process. Flagella then undergo a rotation of 90° until they become parallel to the median cytoplasmic process, followed by the proximodistal fusion of the flagella with the median cytoplasmic process. The nucleus elongates and afterwards it migrates along the spermatid body. Spermiogenesis finishes with the appearance of the apical cone surrounded by the single helical crested body at the base of the spermatid. Finally, the narrowing of the ring of arched membranes detaches the fully formed spermatozoon. The mature spermatozoon of C. crassiceps is filiform and contains two axonemes of the 9+"1" trepaxonematan pattern, a parallel nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the gamete exhibits a short electron-dense apical cone and one crested body, which turns once around the sperm cell. The first axoneme is surrounded by a ring of thick cortical microtubules that persist until the appearance of the second axoneme. Later, these thick cortical microtubules disappear and thus, the mature spermatozoon exhibits two bundles of thin cortical microtubules. The posterior extremity of the male gamete presents only the nucleus. Results are discussed and compared particularly with the available ultrastructural data on the former "pseudophyllideans". Two differences can be stablished between spermatozoa of Bothriocephalidea and Diphyllobothriidea, the type of spermatozoon (II vs I) and the presence/absence of the ring of cortical microtubules.

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Section: Spermiogenesismentioning

confidence: 99%

“…These numerous supplementary characters are constantly increasing the degree of utility of spermatozoon ultrastructure for analysis of cestode phylogeny and evolution (Hoberg et al 1997(Hoberg et al , 1999Justine 2001;Olson et al 2001;Levron et al 2010). …”

Section: Spermatozoonmentioning

confidence: 99%

Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

et al. 2011

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“…Two nuclear ribosomal regions were characterized: the large-subunit (lsrDNA) which has proven to be informative for both phylogenetic and diagnostic studies of the Cestoda (e.g. Brickle et al 2001 ;Olson et al 2001 ;Reyda and Olson, 2003 ;Agustí et al 2005 ;Aznar et al 2007) and the second internal transcribed spacer (ITS-2) which has been commonly used for investigating inter-and intraspecific variation in flatworms (e.g. Verneau et al 1997 ;Zehnder and de Chambrier, 2000 ;Olson et al 2002 ;see Olson andTkach, 2005 andNolan andCribb, 2005).…”

Section: Molecular Analysesmentioning

confidence: 99%

Cryptic species ofDidymobothrium rudolphii(Cestoda: Spathebothriidea) from the sand sole,Solea lascaris, off the Portuguese coast, with an analysis of their molecules, morphology, ultrastructure and phylogeny

et al. 2007

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S U M M A R YDidymobothrium rudolphii (Cestoda : Spathebothriidea) was collected seasonally from the sand sole, Solea lascaris, off the northern, central and southern areas of the Portuguese coast. Morphological and molecular analyses were conducted in order to examine the possible existence of cryptic species and to facilitate the circumscription of their morphological boundaries. Data were compared between D. rudolphii specimens from each of the 3 geographical areas and 4 seasons, and principal components analysis of 18 morphological characters was used to detect differences. Two distinct genotypes were present with sequence divergences of 1 . 9% and 2 . 1% in the large subunit (lsrDNA) and second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA), respectively. The less common ' central' genotype was present only off the central area from summer to winter, whereas the ' common ' genotype was present throughout the year off the northern and southern areas, but only during spring in the central area. No sequence variation was found within each genotype. The presence of 2 distinct genetic entities was supported by morphological analyses, which showed the ' central ' genotype specimens to be more slender and elongate, although morphometric ranges overlapped considerably for most characters. Molecular phylogenetic analysis of 4 of the 5 known genera of the Spathebothriidea showed Spathebothrium to be the earliest branching lineage and the 2 genotypes of Didymobothrium formed a sister group to Cyathocephalus. The concordance of genetic differences with variation in host diet according to season and locality could account for sympatric speciation occurring in the central region of the Portuguese coast.

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“…According to the molecular analysis of Olson et al (2001) the Tetraphyllidea are separated in four groups: the Rhinebothri-*Corresponding author: jordimiquel@ub.edu Abbreviations to all figures: AC -apical cone, AM -arched membranes, ASE -anterior spermatozoon extremity, Ax -axoneme, Ax1 -first axoneme, Ax2 -second axoneme, C -centrioles, C1 -first centriole, C2 -second centriole, CB -crested body, CM -cortical microtubules, D -doublets, F -flagellum, F1 -first flagellum, F2 -second flagellum, G -granules of glycogen, IB -intercentriolar body, MCP -median cytoplasmic process, N -nucleus, PM -plasma membrane, PSE -posterior spermatozoon extremity, S -singlets, SR -striated rootlets inae, the Phyllobothriidae, the Onchobothriidae and the genus Acanthobothrium. Moreover, it is interesting to remark the close relationships between Acanthobothrium and the Proteocephalidea (see Olson et al 2001 andWaeschenbach et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…It is now widely accepted that ultrastructural spermatological characters contribute to a better understanding of relationships within the Platyhelminthes (Euzet et al 1981;Justine 1991Justine , 1995Justine , 1998Justine , 2001Hoberg et al 1997Hoberg et al , 2001Olson et al 2001;Bruňanská 2010;Levron et al 2010). To our knowledge, there are ultrastructural data on the spermiogenesis and/or spermatozoon of four onchobothriids.…”

Section: Introductionmentioning

confidence: 99%

Spermatological characters of Acanthobothrium crassicolle Wedl, 1855 (Tetraphyllidea, Onchobothriidae), a parasite of the common stingray Dasyatis pastinaca

Marigo¹,

Eira²,

Bâ

et al. 2011

Acta Parasitologica

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We describe the spermiogenesis process and the ultrastructural characters of the spermatozoon of Acanthobothrium crassicolle by means of transmission electron microscopy, including cytochemical analysis for glycogen. Spermiogenesis in A. crassicolle begins with the formation of the differentiation zone that contains two centrioles associated with striated rootlets and an intercentriolar body. The latter is formed by one electron-dense layer. The centrioles develop into two free flagella that first grow orthogonally to a median cytoplasmic process and then undergo flagellar rotation becoming parallel to that median cytoplasmic process. After flagellar rotation only one of the flagella completes its growth and both short and long flagella undergo proximodistal fusion with the median cytoplasmic process. In the final stages of spermiogenesis, the nucleus becomes filiform and migrates into the spermatid body. Later, the ring of arched membranes constricts and the spermatozoon is liberated from the residual cytoplasm. The ultrastructural organization of the spermatozoon of A. crassicolle follows the general pattern of spermatozoa of the other Tetraphyllidea-Onchobothriidae species, but exhibits some differences. It is filiform, tapered at both extremities and lacks mitochondrion. It contains two axonemes of unequal length showing the 9 + "1" pattern of Trepaxonemata, a nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the male gamete contains a single crested body surrounding a thin and long apical cone. This type of apical cone has never been described in a tetraphyllidean spermatozoon. Another particularity is the presence of a single electron-dense microtubule at the vertex of the crested body.

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Interrelationships and Evolution of the Tapeworms (Platyhelminthes: Cestoda)

Cited by 285 publications

References 52 publications

Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

Cryptic species ofDidymobothrium rudolphii(Cestoda: Spathebothriidea) from the sand sole,Solea lascaris, off the Portuguese coast, with an analysis of their molecules, morphology, ultrastructure and phylogeny

Spermatological characters of Acanthobothrium crassicolle Wedl, 1855 (Tetraphyllidea, Onchobothriidae), a parasite of the common stingray Dasyatis pastinaca

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