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Abstract Ctenophores are descendants of an early branching basal metazoan lineage, which may have evolved neurons and muscles independently from other animals.Mnemiopsisis one of the important reference ctenophore species. However, little is known about its neuromuscular organization. Here, we mapped and tracked the development of the neural and muscular elements in the early hatching cydippid larvae, as well as adultMnemiopsis leidyi. The overall development of the neuromuscular system inMnemiopsiswas very similar toPleurobrachia bachei, although inMnemiopsisthe entire process occurred significantly faster. The subepithelial neural cells were observed immediately after hatching. This population consisted of a dozen of separated individual neurons with short neurites. In about 2 days, when their neurites grew significantly longer and connected to their neighbors, they began to form a canonical polygonal subepithelial network. Mesogleal neural elements prominent in all studied adult ctenophores were not detectable inMnemiopsislarvae but were clearly labeled in closely related Lobata speciesBolinopsis infundibulum. Hatched larvae also had putative mechanoreceptors with long stereocilia and approximately two dozen muscle cells. In adultMnemiopsis,the feeding lobes and auricles contained two distinct populations of neurons and neural ensembles that were not observed in other ctenophore lineages and likely represented elaborate neuronal innovations characteristic for the clade Lobata and their lifestyles.
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Neural system and receptor diversity in the ctenophore Beroe abyssicola
Abstract Although, neurosensory systems might have evolved independently in ctenophores, very little is known about their organization and functions. Most ctenophores are pelagic and deep‐water species and cannot be bred in the laboratory. Thus, it is not surprising that neuroanatomical data are available for only one genus within the group—Pleurobrachia. Here, using immunohistochemistry and scanning electron microscopy, we describe the organization of two distinct neural subsystems (subepithelial and mesogleal) and the structure of different receptor types in the comb jellyBeroe abyssicola—the voracious predator from North Pacific. A complex subepithelial neural network ofBeroe, with five receptor types, covers the entire body surface and expands deep into the pharynx. Three types of mesogleal neurons are comparable to the cydippidPleurobrachia. The predatory lifestyle ofBeroeis supported by the extensive development of ciliated and muscular structures including the presence of giant muscles and feeding macrocilia. The obtained cell‐type atlas illustrates different examples of lineage‐specific innovations within these enigmatic marine animals and reveals the remarkable complexity of sensory and effector systems in this clade of basal Metazoa.
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- Award ID(s):
- 1645219
- PAR ID:
- 10374580
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Comparative Neurology
- Volume:
- 527
- Issue:
- 12
- ISSN:
- 0021-9967
- Page Range / eLocation ID:
- p. 1986-2008
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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