Molecular systematics of the Acoela (Acoelomorpha, Platyhelminthes) and its concordance with morphology

Hooge, Matthew D.; Haye, Pilar A.; Tyler, Seth; Litvaitis, Marian K.; Kornfield, Irv

doi:10.1016/s1055-7903(02)00236-1

Cited by 62 publications

(73 citation statements)

References 28 publications

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“…The advent of molecular techniques and the use of 18S rRNA sequence data have been shown to be effective in determining the phylogenetic relationships of acoels (Hooge et al 2002). In the present study we demonstrated that the acoel worms inhabiting corals in Eilat's coral reef are genetically similar and most probably belong to the same species.…”

Section: Resultssupporting

confidence: 56%

“…They are a morphologically varied group of soft-bodied worms (Hooge et al 2002) lacking a gut cavity and protonephridia (Tyler 2003). Acoels have been reported to inhabit both pelagic and littoral environments (McCoy & Balzer 2002) and are known to include species that are epibenthic, epiphytic (Hooge & Tyler 2006) and epizoic on live coral colonies (Trench & Winsor 1987, Winsor 1990, Barneah et al 2007a.…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have devoted intensive efforts to obtain finer resolutions of the systematics of the acoel species in several families (Hooge et al 2002. One such work is that by , who re-organized and revised the largest acoel family, the Convolutidae, which con-tains one-third of the Acoela species including the genus Waminoa, the focus of the present study.…”

Section: Introductionmentioning

confidence: 99%

“…One such work is that by , who re-organized and revised the largest acoel family, the Convolutidae, which con-tains one-third of the Acoela species including the genus Waminoa, the focus of the present study. In a phylogenetic investigation of the Acoela using the nuclear 18S rRNA gene, Hooge et al (2002) produced a gene tree that revealed a polyphyletic Convolutidae, with larger, endosymbiont-containing acoels grouped separately from small-bodied species. The latter were eventually moved to a new family, the Isodiametridae.…”

Section: Introductionmentioning

confidence: 99%

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Molecular diversity and specificity of acoel worms associated with corals in the Gulf of Eilat (Red Sea)

Barneah¹,

Ben‐Dov²,

Benayahu³

et al. 2012

Aquat. Biol.

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Epizoic acoel worms are known to inhabit several stony coral genera and one soft coral genus in Eilat (Red Sea). Such acoels were recently found to belong to the genus Waminoa and a new species was described: W. brickneri. Worms isolated from several coral species exhibited variability in size and reproductive state, suggesting the presence of more than one species of Waminoa. In the present study we examined the 18S rRNA gene sequences of worms from 6 genera of stony corals from the Gulf of Eilat to reveal the genetic variability of the worms and to study the specificity between these worms and the corals on which they live. The sequences obtained were found to be genetically similar, and they formed a distinct cluster with the 18S rRNA gene sequence of W. brickneri. Our results demonstrate that corals belonging to 6 different genera harbored genetically similar worms and thus suggest the existence of low specificity between worms and their coral hosts.KEY WORDS: Acoela · Waminoa · Epizoic worms · Specificity · Coral reef · EilatResale or republication not permitted without written consent of the publisher

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Section: Resultssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Molecular diversity and specificity of acoel worms associated with corals in the Gulf of Eilat (Red Sea)

Barneah¹,

Ben‐Dov²,

Benayahu³

et al. 2012

Aquat. Biol.

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“…Spermatozoa of acoelomorphs are typically elongate and biflagellate. The ultrastructural features of spermatozoa in acoelomorphs have proved to be a rich source of phylogenetic characters that are concordant with studies of molecular systematics (Hooge et al 2002;Petrov et al 2004). Egg laying in the Acoelomorpha is carried out either through the mouth or through a tear in the epidermis.…”

mentioning

confidence: 69%

First evidence of maternal transmission of algal endosymbionts at an oocyte stage in a triploblastic host, with observations on reproduction inWaminoa brickneri(Acoelomorpha)

Barneah

Brickner

Hooge

et al. 2007

Invertebrate Biology

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Abstract. Examination of sexual reproduction in a symbiotic acoelomorph worm, Waminoa brickneri from Eilat (Red Sea), presents the first definitive evidence for maternal transmission of dinoflagellate algal symbionts in a triploblastic organism. Sexually mature worms were removed from the stony coral Plesiastrea laxa and raised in the laboratory. Eggs were detected 18 d after the collection of the worms and hatched 4 d later. Histological sections performed on sexually mature worms showed an ovary with oocytes containing two distinct types of algal endosymbionts within their ooplasm. Transmission electron microscopy corroborated the presence of algal symbionts within the developing embryos. Our findings regarding maternal transmission of symbionts shed new light on the diversity of modes of algal symbiont acquisition known in triploblastic organisms.

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Comparative morphology of the bursal nozzles in acoels (Acoela, Acoelomorpha)

Petrov

Hooge

Tyler

2006

Journal of Morphology

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Systematics of the Acoela is particularly difficult because of the paucity of readily discernible morphological features. In other soft-bodied worms, sclerotized structures, such as copulatory stylets, provide important characters that can be seen in whole mounts, but acoels generally lack such features. Among the few sclerotized structures in acoels are bursal nozzles-tubiform outlets on the seminal bursae that are believed to be conduits (spermatic ducts) through which allosperm are transported to the oocytes. Early classifications of the Acoela used features of the female reproductive system, including bursal nozzles, for distinguishing major groups, but the current system essentially ignores them as too plastic to provide higher-level distinctions. We used confocal and electron microscopy to further characterize bursal nozzles in five acoel species, and found all composed of actin-reinforced extensions of stacked, flat mesenchymal cells. In Notocelis gullmarensis, Aphanostoma bruscai, and Daku woorimensis, the nozzle is a stiffened region of the same cells forming the wall of the bursa. By contrast, in Wulguru cuspidata cells forming the nozzle are distinct from those of the bursa. The so-called bursal cap of A. bruscai and D. woorimensis has small sclerotized disjunct units within it, also composed of stacked, flat, actin-reinforced cells. The nozzle of W. cuspidata, prominent like that of other convolutid acoels, is relatively complex, its actin-reinforced cells sandwiched with secretory cells and its base bearing a "sorting apparatus" of egg-shaped cells that send narrow processes inside the spermatic duct. Cases of sperm inside the nozzle corroborate its assumed role in reproduction. Whereas most nozzles sit at the end of the bursa facing the ovary, in species of Pseudmecynostomum and purportedly in a few other acoels, they sit between the female pore and the bursa, constituting what we call a vaginal nozzle. All bursal nozzles of acoels show a common ground pattern indicating common ancestry, but certain features discerned through electron and confocal microscopy show promise of providing synapomorphies for grouping some species.

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Molecular systematics of the Acoela (Acoelomorpha, Platyhelminthes) and its concordance with morphology

Cited by 62 publications

References 28 publications

Molecular diversity and specificity of acoel worms associated with corals in the Gulf of Eilat (Red Sea)

Molecular diversity and specificity of acoel worms associated with corals in the Gulf of Eilat (Red Sea)

First evidence of maternal transmission of algal endosymbionts at an oocyte stage in a triploblastic host, with observations on reproduction inWaminoa brickneri(Acoelomorpha)

Comparative morphology of the bursal nozzles in acoels (Acoela, Acoelomorpha)

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