Record Details
The comparative histology of light organs in four Pacific myctophids of the genus, Lampanyctus
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The comparative histology of light organs in four Pacific myctophids of the genus, Lampanyctus |
| Names |
Wyandt, Herman Edwin, 1939-
(creator) Owczarzak, Alfred (advisor) |
| Date Issued | 1965-05-14 (iso8601) |
| Note | Graduation date: 1966 |
| Abstract | A comparative study was made of the morphology and histology of three major groups of light organs in the genus Lampanyctus of the family Myctophidae for the species, L. leucopsarus, L. ritteri, L. nannochir, and L. regalis. The species can be divided according to their ranges in depth, the first two named above coming to surface waters at night, the other pair remaining at greater depths. The organs studied included complex organs on the trunk ("Schusselformigie" organs) and in the lower jaw (branchiostegal organs), and less specialized organs on the caudal peduncle (infra- and supracaudal organs). The morphology of the three groups was found to vary with species and depth, in size and form of the constituent elements, but otherwise supported and supplemented previous observations made for other genera of the family. The elements of the most complex organs ("Schusselformigie" organs) consisted of a lens, photogenic gland, vascular and connective tissue, and an inner scale and reflector backed by pigment. The lens and inner scale were lacking in the branchiostegal organs. The less specialized caudal organs consisted mainly of glandular tissue interspersed with blood vessels and connective tissue. Changes in morphology of the trunk organs of the deeper animals were found. Included were a marked decrease in the size of the organs in L. regalis and a lessening in amount of glandular tissue in L. nannochir. The most significant histological difference was the unusually large capillary bed found in the trunk organs and branchiostegal organs of L. nannochir which contrasts with a very sparse blood supply to these organs in L. regalis. However, the caudal organs of these species did not manifest this divergence in structure, suggesting a difference in function between the two groups of organs. This interpretation was supported somewhat by the observed difference in luminescence of the two groups. The branchiostegal and trunk organs produced a continuous low intensity luminescence while the caudal organs displayed a more brilliant intermittent flashing. An additional histological difference was the prolific supply of nerves to the caudal organs and the conspicuous lack of nerves to the complex trunk organs. Large nerve branches to the branchiostegal organs, however, did not support a correlation between intensity and character of light produced and the degree of innervation. A further study of physiological mechanisms controlling luminescence in these species is needed. |
| Genre | Thesis/Dissertation |
| Topic | Lampanyctus |
| Identifier | http://hdl.handle.net/1957/47601 |
