Visual pigments of the tree shrew (Tupaia belangeri) and greater galago (Galago crassicaudatus): a microspectrophotometric investigation

Vision Res. 1990;30(6):839-51. doi: 10.1016/0042-6989(90)90053-n.


Optical density, linear dichroism and bleaching difference spectra were measured in photoreceptors from the cone-dominated retina of the tree shrew (Tupaia belangeri) and from the rod-dominated retina of the greater galago (Galago crassicaudatus) using a single-beam, wavelength-scanning, dichroic microspectrophotometer. In Tupaia, we obtained spectral records from 272 cone receptors (from 10 eyes), of which 264 were long-wave sensitive (lambda max = 555 +/- 6 nm) and 8 were short-wave sensitive (lambda max = 428 +/- 15 nm). Also, one anatomically-recognizable rod receptor was encountered and showed a peak absorption at approx. 496 nm. No mid-wave sensitive cone pigment was found, as would be expected in deutan-type dichromats like the tree shrew. Pre-retinal absorption by the cornea and lens was maximal at 370 nm and negligible beyond 430 nm. In Galago, all outer segments measured were rod-like in appearance (lambda max near 501 nm). Measurements of pre-retinal absorption yielded a single-peaked function with a maximum at 363 nm.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Absorption
  • Animals
  • Circular Dichroism
  • Color Perception
  • Female
  • Galago*
  • Lens, Crystalline / analysis
  • Male
  • Optical Rotation
  • Photoreceptor Cells / analysis*
  • Retinal Pigments / analysis*
  • Spectrophotometry
  • Tupaiidae*


  • Retinal Pigments