New acoels (Acoela, Acoelomorpha) from North Carolina

Hooge, Matthew D.; Smith, Julian P.

doi:10.11646/zootaxa.442.1.1

Cited by 18 publications

(15 citation statements)

References 9 publications

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“…The pharynx of species of the monogeneric Proporidae has been described as a simple terminal or subterminal invagination of the body wall lacking sphincters at the mouth and at the juncture to the digestive parenchyma (see also Dörjes, 1971;Hooge and Tyler, 2001;Hooge and Smith, 2004). It has been shown here, however, that at least the pharynx of Proporus bermudensis is not as simple as suggested by Dörjes (1971) for other species of the genus.…”

Section: Family-level Pharynx Charactersmentioning

confidence: 53%

“…This sphincter is located below the longitudinal muscles and is thus independent from the circular muscle layer of the pharynx. Diopisthoporus gymnopharyngeus Smith and Tyler, 1985, has a weak terminal sphincter and in D. psammophilus Doerjes, 1968, and D. lofotilis Hooge and Smith, 2004 there is no distinct sphincter at all. In D. brachypharyngeus Doerjes, 1968, there is a strong sphincter and an additional bulbous muscle sheath surrounding the muscular pharynx wall and connected to it by radial fibers.…”

Section: Family-level Pharynx Charactersmentioning

confidence: 99%

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Structure and evolution of the pharynx simplex in acoel flatworms (Acoela)

Todt

2008

Journal of Morphology

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The homology of pharynges within the mostly pharynx-less Acoela has been a matter of discussion for decades and even the basic question of whether a pharynx is a primitive trait within the Acoela and homologous to the pharynx of platyhelminth turbellarians is open. By using fluorescence staining of musculature, as well as conventional histological techniques and transmission electron microscopy, the present study sets focus on the mouth and pharynx (where present) of seven species of Acoela within Paratomellidae, Solenofilomorphidae, Hofsteniidae, Proporidae, and Convolutidae, as well as one species of Nemertodermatida and Catenulida, respectively. It is shown that among the investigated families of acoels there is a great variability in muscle systems associated with the mouth and pharynx and that pharynx histology and ultrastructural characters are widely diverse. There are no close similarities between the acoel pharynges and the catenulid pharynx but there is a general resemblance of the musculature associated with the mouth in the representatives of Paratomellidae and Nemertodermatida. On the basis of the profound differences in pharynx morphology, three major conclusions are drawn: 1) the pharynges as present in Recent acoels are not homologous to the pharynx simplex characteristic for Catenulida and Macrostomida within the Platyhelminthes; 2) the different muscular pharynx types of acoels are not homologous between higher taxa and thus a single acoel-type pharynx simplex cannot be defined; 3) the presence of a muscular pharynx most likely does not represent the ancestral state.

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Section: Family-level Pharynx Charactersmentioning

confidence: 53%

Section: Family-level Pharynx Charactersmentioning

confidence: 99%

Structure and evolution of the pharynx simplex in acoel flatworms (Acoela)

Todt

2008

Journal of Morphology

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“…2007). Also remarkable are the reductions of complexity in the ventral body wall of the long and slender interstitial species Anaperus singularis Hooge and Smith, 2004 and Convoluta niphoni Achatz, 2008 (Achatz 2008). Finally it should be mentioned that stronger individual muscles might appear in the vicinity of nerve cords (for Convoluta lacrimosa Achatz et al., 2007 and Conaperta cirrata Achatz et al., 2007 data not shown, for C. schuelii see Achatz 2008) and that in larger animals like C. convoluta longitudinal muscles appear to be organized in ribbons, similar to the pattern described for sipunculids (Wanninger et al.…”

Section: Resultsmentioning

confidence: 99%

“…It is likely that a glandular secretion activates the sperm after ejection (Dörjes 1968; p. 357), and, therefore, the practical location for such glands would be at the proximal part of the copulatory structure and ventral to the sperm. There are several acoel species from various families that lack a penis and have an antrum with a vesicula granulorum at its proximal part – for example Antrosagittifera corallina Hooge and Tyler 2001; Kuma flava Hooge and Smith 2004; Parahaploposthia avesicula Dörjes 1968; Parahaploposthia cerebroepitheliata Dörjes 1968; Eumecynostomum westbladi Dörjes 1968; Symsagittifera smaragdina Achatz et al. 2005.…”

Section: Resultsmentioning

confidence: 99%

Systematic revision of acoels with 9+0 sperm ultrastructure (Convolutida) and the influence of sexual conflict on morphology

Achatz

Hooge

Wållberg

et al. 2010

Journal of Zoological Systematics and Evolutionary Research

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We have used newly discerned morphological characters as well as molecular-sequence data from 18S and 28S rDNA to revise the families recently designated as the Ô9+0Õ acoels -what we call Convolutida. Characters from the ultrastructure of sperm, with their Ô9+0Õ axonemes, are useful in delineating the Convolutida, but are either species-specific or too conserved within the group to be used to infer relationships within it. Male genital organs, prostatoid organs, and sagittocysts, on the other hand, give a good phylogenetic signal for reconstructing relationships of such genera as Conaperta, Anaperus, and Achoerus; some features of the reproductive organs correlate with habitat and show how the Convolutida probably originated as epiphytic predators and radiated into the mesopsammon, pelagic, and coral-associated realms. In this revision of the Convolutida we provide revised synopses of its families -which we restrict to the Anaperidae, Convolutidae, and Sagittiferidae -and describe a new species, Polychoerus gordoni, from New Zealand. We transfer the genus Adenopea from the Antroposthiidae to the Convolutidae; Conaperta, Neochildia, and Oxyposthia from the Convolutidae to the Anaperidae; Paranaperus and Praeanaperus from the Anaperidae to the Haploposthiidae. Convoluta aegyptica is synonymized with Convoluta boehmigi, Convoluta lacazii with Convoluta sordida, and the genus Picola (Convolutidae) with Deuterogonaria (Haploposthiidae). Amphiscolops blumi, A. carvalhoi, and A. langerhansi, all of which possess a cellular seminal bursa, are transferred to the genus Heterochaerus. Convoluta elegans and Pseudanaperus tinctus are classified as nomina nuda. We use our findings on the ultrastructure of female genital organs and spermatozoa to show that sexual conflict plays a major role in the evolution of diversity of these structures and that the phylogeny of the Acoela would comprise early forms without female genital organs and hyper-or hypodermal transfer of sperm through advanced forms with ever longer and narrower bursal nozzles and sperm with axial microtubules. Moreover, our results show that the acquisition of endosymbiotic algae happened at least twice within the Acoela.

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“…As part of an ongoing investigation of the taxonomy and biogeography of the Acoela (Hooge 2003, Hooge & Smith 2004, Hooge & Tyler 2001, 2003a,b, 2005, we collected acoels from San Felipe Bay, Baja, Mexico in February 2004. We report here our finding of three previously unknown species.…”

Section: Introductionmentioning

confidence: 99%