Cone photoreceptors lacking oil droplets in the retina of the echidna, Tachyglossus aculeatus (Monotremata)

Young H.M. and Pettigrew J.D. (1991) Cone photoreceptors lacking oil droplets in the retina of the echidna, Tachyglossus aculeatus (Monotremata). Visual Neuroscience, 6 5: 409-420. doi:10.1017/S0952523800001279


Author Young H.M.
Pettigrew J.D.
Title Cone photoreceptors lacking oil droplets in the retina of the echidna, Tachyglossus aculeatus (Monotremata)
Journal name Visual Neuroscience   Check publisher's open access policy
ISSN 1469-8714
Publication date 1991-01-01
Sub-type Article (original research)
DOI 10.1017/S0952523800001279
Volume 6
Issue 5
Start page 409
End page 420
Total pages 12
Subject 2809 Sensory Systems
1314 Physiology
2800 Neuroscience
Abstract The echidna, Tachyglossus aculeatus, a monotreme mammal, is thought to possess an all-rod retina (O'Day, 1952). This study provides anatomical evidence for the presence of cone-like photoreceptors in the retina of the echidna. The cones, which constitute 10-15% of the photoreceptors, have all of the ultrastructural characteristics previously shown in the cones of placental mammals, and, like the cones of other animals (Blanks & Johnson, 1984), they bind peanut agglutinin. Unlike the cones of another monotreme, the platypus, the cones of the echidna retina do not possess oil droplets. Twin cones, pairs of cones in which there is no obvious difference in the size, shape, or ultrastructural features of the members of a pair, are common. The density of cones varies from 9000 cells/mm2in the superior periphery to 22,000 cells/mm2in the central retina. Nearest-neighbor analysis suggests that the cone mosaic in the echidna retina results from the presence of single and twin cones in a relatively regular array.
Keyword Monotreme
Oil droplets
Photoreceptors
Retina
Ultrastructure
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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Created: Tue, 05 Jul 2016, 13:12:57 EST by System User