Table 1.

AHPO quantification of melanin markers in extant and fossil frogs

Taxon	Tissue	PTCA (ng/mg)	PDCA (ng/mg)	PTeCA (ng/mg)	PTeCA/PTCA	4-AHP (ng/mg)
X. laevis	Liver	128	8.1	60.7	0.47	2.9
	Lung	73.7	5.9	29.2	0.40	4.3
	Spleen	12.8	1.0	17.4	1.36	0.6
P. pueyoi	Torso	258	36.9	486	1.88	–

PTCA and PDCA are markers for eumelanin; 4-AHP is a marker for phaeomelanin and PTeCA is a marker for diagenetically altered eumelanin⁹