Ultrastructure of Presumed Ocelli in <i>Parenterodrilus taenioides</i> (Polychaeta, Protodrilidae) and their Phylogenetic Significance

Purschke, Günter; Jouin-Toulmond, C.

doi:10.1111/j.1463-6395.1993.tb01239.x

Cited by 19 publications

(15 citation statements)

References 28 publications

(39 reference statements)

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“…However, the placement of this clade among the annelids remains without certain phylogenetic relationships. Other phaosomes were found in species of Parenterodrilus taeniodes (Protodrilidae), Nephthys caeca (Nephtyidae) or Stylaria lacustris (Naididae, Clitellata) but there are major differences to S. armiger (Purschke and Jouin Toulmond, 1993;Zahid and Golding, 1974;Purschke, 2003). Recent evidence suggests that the phaosomes of Clitellata represent modified rhabdomeric photoreceptor cells or receptor cells newly evolved in Clitellata (Purschke et al, 2006).…”

Section: Ciliary Photoreceptor-like Sense Structuresmentioning

confidence: 96%

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Wilkens

Purschke

2009

Journal of Morphology

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The phylogenetic position of Orbiniidae within Annelida is unresolved. Conflicting hypotheses place them either in a basal taxon Scolecida, close to Spionida, or in a basal position in Aciculata. Because Aciculata have a specific type of eye, the photoreceptive organs in the orbiniid Scoloplos armiger were investigated to test these phylogenetic hypotheses. Two different types of prostomial photoreceptor-like sense organs were found in juveniles and one additional in subadults. In juveniles there are four ciliary photoreceptor-like phaosomes with unbranched cilia and two pigmented eyes. The paired pigmented eyes lie beside the brain above the circumoesophageal connectives. Each consists of one pigmented cell, one unpigmented supportive cell and three everse rhabdomeric sensory cells with vestigial cilia. During development the number of phaosomes increases considerably and numerous unpigmented sense organs appear consisting of one rhabdomeric photoreceptor cell and one supportive cell. The development and morphology of the pigmented eyes of S. armiger suggest that they represent miniaturized eyes of the phyllodocidan type of adult eye rather than persisting larval eyes resulting in small inverse eyes typical of Scolecida. Moreover, the structure of the brain indicates a loss of the palps. Hence, a closer relationship of Orbiniidae to Phyllodocida is indicated. Due to a still extensive lack of ultrastructural data among polychaetes this conclusion cannot be corroborated by considering the structure of the unpigmented ciliary and rhabdomeric photoreceptor-like sense organs.

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Section: Ciliary Photoreceptor-like Sense Structuresmentioning

confidence: 96%

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Wilkens

Purschke

2009

Journal of Morphology

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“…This fact has either been overlooked because the supportive cells are relatively inconspicuous, or it has simply been neglected (e.g., Sensenbaugh & Franze´n, 1987;Rhode, 1991). True phaosomes are, for instance, present in the palps of Protodrilidae (Purschke, 1993(Purschke, , 2003Purschke & Jouin-Toulmond, 1993) or in Siboglinidae (Nørrevang, 1974).…”

Section: Photoreceptor-like Sense Organsmentioning

confidence: 97%

Sense organs in polychaetes (Annelida)

Purschke

2005

Hydrobiologia

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151

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Polychaetes possess a wide range of sensory structures. These form sense organs of several kinds, including the appendages of the head region (palps, antennae, tentacular cirri), the appendages of the trunk region and pygidium (parapodial and pygidial cirri), the nuchal organs, the dorsal organs, the lateral organs, the eyes, the photoreceptor-like sense organs, the statocysts, various kinds of pharyngeal papillae as well as structurally peculiar sensory organs of still unknown function and the apical organs of trochophore larvae. Moreover, isolated or clustered sensory cells not obviously associated with other cell types are distributed all over the body. Whereas nuchal organs are typical for polychaetes and are lacking only in a few species, all other kinds of sensory organs are restricted to certain groups of taxa or species. Some have only been described in single species till now. Sensory cells are generally bipolar sensory cells and their cell bodies are either located peripherally within the epidermis or within the central nervous system. These sensory cells are usually ciliated and different types can be disinguished. Structure, function and phylogenetic importance of the sensory structures observed in polychaetes so far are reviewed. For evaluation of the relationships of the higher taxa in Annelida palps, nuchal organs and pigmented ocelli appear to be of special importance.

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“…These two cell types form an extracellular cavity containing the sensory structures (Purschke 1992;Verger-Bocquet 1992;Purschke and Jouin-Toulmond 1993;Purschke and Müller 1996). The supporting cells normally form a thin envelope around the cilia and thus may easily be overlooked.…”

Section: Ciliary Sense Organs and Sensory Cellsmentioning

confidence: 99%

“…Although apparently simply organised sensory structures, these ciliary sense organs exhibit a remarkable diversity in terms of position in the anterior end, ultrastructure of sensory cilia as well as number and structure of the sensory cells themselves. Thus, with the exception of the ciliary sense organs described in Naididae, Enchytraeidae and Tubificidae, homology assessments between the more highly ranked taxa are hard to make; the organs are useful for phylogenetic considerations only on lower levels of the system (see, for example, Purschke and Jouin-Toulmond 1993). The ciliary sense organs found in A. hemprichi, however, differ clearly from those found in "Oligochaeta" both in structure and position.…”

Section: Ciliary Sense Organs and Sensory Cellsmentioning

confidence: 99%

Immunohistochemical (cLSM) and ultrastructural analysis of the central nervous system and sense organs in Aeolosoma hemprichi (Annelida, Aeolosomatidae)

Hessling¹,

Purschke²

2000

Zoomorphology

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The Aeolosomatidae are very small limnetic or terrestrial annelids of apparently simple organisation and uncertain phylogenetic position. They have been placed either at the base of the Clitellata, as a highly derived taxon within the Clitellata closely related to the Naididae, or as their sister group within the "Polychaeta". A combined immunohistochemical (cLSM) and ultrastructural investigation of the central nervous system and the sense organs in Aeolosoma hemprichi was undertaken to look for characters which might support one of these theories. The position of the brain within the prostomium and the organisation of the ventral nerve cord, with its intraepithelial paired longitudinal nerves lying far apart from each other and the presence of a median longitudinal nerve, are atypical for the Clitellata and clearly differ from the situation found in Naididae. Moreover, the circumoesophageal connectives are bifurcated and enter the brain as dorsal and ventral roots; this arrangement is unknown in Clitellata, in which these connectives are unbranched. An ultrastructural analysis of the ciliated pits located laterally in the furrow between prostomium and peristomium in A. hemprichi and other Aeolosomatidae show that they are in fact nuchal organs. Such presumed chemosensory organs are typical of "Polychaeta" and absent in all Clitellata. Two pairs of ciliary sense organs are present in the prostomium in front of the brain of A. hemprichi. Although similarly organised sensory structures occur in many species of the Clitellata, they differ in position and certain ultrastructural features and are known from other Annelida as well. These results clearly support the exclusion of the Aeolosomatidae from the Clitellata and do not provide any evidence for a sister-group relationship between these two taxa.

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Ultrastructure of Presumed Ocelli in Parenterodrilus taenioides (Polychaeta, Protodrilidae) and their Phylogenetic Significance

Cited by 19 publications

References 28 publications

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Sense organs in polychaetes (Annelida)

Immunohistochemical (cLSM) and ultrastructural analysis of the central nervous system and sense organs in Aeolosoma hemprichi (Annelida, Aeolosomatidae)

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