Structure and Innervation of the Inner Ear Sensory Organs in an Otophysine Fish, the Upside–down Catfish (Synodontis nigriventrisDavid)

Abstract

Jensen, J. C. 1994. Structure and innervation of the inner ear sensory organs in an otophysine fish, the upside-down catfish (Synodontis nigriventris David).-Acta Zoologica (Stockholm) 75: 14S160.All the sensory epithelia of the inner ear in the upside-down catfish (Synodontis nigriventris David) were examined by light microscopy. The morphology of the membranous labyrinth and the orientation of the hair cells is similar to what has been found in other otophysine fishes. The sensory cells are of variable size both inter-and intraepithelially; particularly the macula sacculi is equipped with heterogeneous receptors. Regional differences in the hair cell density are presented for all the otolith organs plus the papilla neglecta. Nerve stainings reveal regional differentiation. The central areas are innervated by stout and stubbly nerve endings intermingled with a few thin nerve fibres while the peripheral parts are reached exclusively by thin axons. In the anterior region of the macula sacculi are found unique cup-shaped axon terminations which surround the basal parts of a single or a few sensory cells. The number and diameter range of the myelinated nerve fibres as well as the hair celVaxon ratio are presented. Electron microscopy demonstrates the presence of unmyelinated axons in all inner ear nerve ramuli.

The polarization of inner ear ciliary bundles from a scorpaeniform fish

“…Jensen (1994) used a light microscope to reveal ciliary bundle orientations in the end organs of the upside‐down catfish Synodontis nigriventris David, along with observations of innervating nerve distributions. Lu & Popper (1998) examined the polarization of ciliary bundles in the end organs of the sleeper goby Dormitator latifrons (Richardson) using immunocytochemicals and a confocal imaging technique.…”

Structure and Growth of the Utricular Macula in the Inner Ear of the Slider Turtle Trachemys scripta

“…The crocodile Melanosuchus is placed among the birds. Considering that the crocodiles in many aspects resemble birds more than they (Mathiesen 1985); Sorex araneus, mean value of 4 animals (Kirkegaard and Jørgensen 2001); Ahaetulla prasina, mean value of 2 animals (Jørgensen 1988); Trachemys scripta (newly hatched), mean value of 2 animals (present study); Rattus norvegicus, mean value of 8 animals (Lindenlaub et al 1995); Testudo graeca, mean value of 2 animals (Jørgensen 1988); Cryptomy sp., mean value of 8 animals (Lindenlaub et al 1995); Spalax ehrenbergi, mean value of 8 animals (Lindenlaub et al 1995); Trachemys scripta (sexuallly mature), mean value of 2 animals (present study); Cavia cobaya, mean value of 5 animals (Lindeman 1969b); Saimiri sciureus, mean value of 8 animals (Igarashi et al 1975); Trachemys scripta, old (large) turtles, mean value of 2 animals (present study); Melopsittacus undulatus, mean value of 5 juveniles and 4 adults (Jørgensen 1991); Anguilla anguilla (Yellow eel) (Mathiesen 1985); Eretmochelys imbricata, mean value of 2 animals (Severinsen, personal observation); Synodontis nigriventris (Jensen 1994); Anguilla anguilla (Silver eel) (Mathiesen 1985); Melanosuchus niger, mean value of 2 juvenile animals (Jørgensen 1988); Columba livia, mean value of 7 animals (Rosenhall 1970); Catharacta skua (Jørgensen 1989);Corvus corone cornix (Jørgensen 1989); Homo sapiens, mean value of two studies by Rosenhall (1972) (13 individuals) and by Watanuki and Schukencht (1976) (2 individuals); Pluvialis apricaria (Jørgensen 1989) Tachyglossus aculetus, mean value of 3 animals (Jørgensen and Locket 1995). b.…”

Morpho‐anatomy of the otic region in carapid fishes: eco‐morphological study of their otoliths

“…The pars inferior is particularly well developed and seems dorsally to push away the pars superior, which means that the height of the pars superior is shorter, the sinus superior is broader, and the utricilus is narrower than in other teleosts (Grassé, 1958;Dale, 1976;Popper & Coombs, 1980;Platt & Popper, 1981;Popper, 1982). However, the observed differences in the size and shape of the semi-circular canals in teleosts do not seem to be linked to any fish mode of living (Platt & Popper, 1981;Jensen, 1994). The development of the pars inferior also appears laterally, to the extent that the sacculi and lagenae occupy ventrally the entire otic region and meet in the sagittal plane (Fig.…”