Fig. 3From: Color vision evolution in egg-laying mammals: insights from visual photoreceptors and daily activities of Australian echidnasAbsorption spectra of monotreme LWS opsins. Dark spectra and difference spectra of echidna a, b and platypus c, d are shown, respectively. λmax could not be calculated in dark spectra of monotreme LWS due to low absorbance. Light and dark spectra of 450–650 nm are enlarged to highlight the absolute spectra around the λmaxBack to article page