Morphological and molecular characterization of tetraphyllidean merocercoids (Platyhelminthes: Cestoda) of striped dolphins (<i>Stenella coeruleoalba</i>) from the Western Mediterranean

Agusti, Celia; Aznar, Francisco Javier; Olson, Peter D.; Littlewood, D. Timothy J.; Kostadinova, Aneta; Raga, Juan Antonio

doi:10.1017/s0031182004006754

Cited by 41 publications

(46 citation statements)

References 18 publications

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“…Using a molecular approach, they successfully identified orga nisms that played a role in the trophic transmission of these tapeworms to their definitive hosts. However, a major limitation of this approach is the paucity of molecular data for most adult marine tapeworms (Brickle et al 2001, Agusti et al 2005, Aznar et al 2007, Jensen & Bullard 2010. As of August 2010, fewer than 20% of described marine tapeworm taxa have been characterised molecularly (authors' unpubl.…”

Section: Introductionmentioning

confidence: 99%

“…The probability of finding sequence matches between larvae and adults is therefore relatively low. Consequently, there are some larval sequences in GenBank that are unmatched to adult forms (Brickle et al 2001, Agusti et al 2005, Aznar et al 2007, Jensen & Bullard 2010. For instance, one plerocercoid and one merocercoid from the squid Doryteuthis gahi were molecularly characterised at the 5' end of the large subunit ribosomal DNA (D1-D3 LSU rDNA), but neither matched those of adult forms (Brickle et al 2001).…”

Section: Introductionmentioning

confidence: 99%

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Larval parasite gene sequence data reveal cryptic trophic links in life cycles of porbeagle shark tapeworms

Randhawa¹,

Brickle²

2011

Mar. Ecol. Prog. Ser.

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The lack of information on marine tapeworm life cycles can be addressed with knowledge derived from trophic interactions in marine environments. These trophically transmitted parasites exploit transmission routes involving predator-prey interactions. Porbeagle sharks Lamna nasus are apex predators feeding on a wide range of organisms, including teleosts and cephalopods. Although the biology of this shark species is relatively well studied, there is a surprising lack of information about the trophic interactions involving this species that lead to the acquisition of tapeworms. Recently, the use of molecular tools, combined with phylogenetics, has proven useful in identifying trophic links involved in the transmission of marine tapeworms. In the present study, we used sequence data from the D2 domain of the large subunit ribosomal DNA to link adult tapeworms of the species Clistobothrium cf. montaukensis and Dinobothrium sp. parasitising porbeagle sharks to larvae recovered from the squid Doryteuthis gahi. To the best of our knowledge, it is the first to provide empirical evidence for a trophic link between porbeagle sharks and D. gahi as a definitive route for the successful transmission of these tapeworms. Furthermore, our data suggest an ontogenetic shift in diet away from squid. Parasite abundance data in D. gahi indicate that the abundance of porbeagle sharks can be significant in some years.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Larval parasite gene sequence data reveal cryptic trophic links in life cycles of porbeagle shark tapeworms

Randhawa¹,

Brickle²

2011

Mar. Ecol. Prog. Ser.

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“…1A,B): the apical sucker (in the case of the plerocercoids) or the apical organ (in the case of the merocercoids); the apical region of the scolex (equivalent to the "apical modification of the scolex proper" in the case of merocercoids; see Agustí et al, 2005b); the adherent surface of the bothridial accessory suckers; the proximal surface of the bothridial loculus (nonadherent surface); and the distal surface of the bothridial loculus (adherent surface). In addition, the following regions of the body were examined: in the case of the plerocercoids, three points along the body length, i.e., anterior, midlength, and posterior; in the case of the merocercoids, the anterior part of the filament that connects the scolex with the bladder.…”

Section: Methodsmentioning

confidence: 99%

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

Agusti¹,

Aznar²,

Raga³

2005

Journal of Morphology

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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.

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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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Morphological and molecular characterization of tetraphyllidean merocercoids (Platyhelminthes: Cestoda) of striped dolphins (Stenella coeruleoalba) from the Western Mediterranean

Cited by 41 publications

References 18 publications

Larval parasite gene sequence data reveal cryptic trophic links in life cycles of porbeagle shark tapeworms

Larval parasite gene sequence data reveal cryptic trophic links in life cycles of porbeagle shark tapeworms

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

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

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