Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles

  title={Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles},
  author={Johan Lindgren and Peter Sj{\"o}vall and Ryan M Carney and Per Uvdal and Johan A. Gren and Gareth J. Dyke and Bo P. Schultz and Matthew D. Shawkey and Kenneth R. Barnes and Michael J. Polcyn},
Throughout the animal kingdom, adaptive colouration serves critical functions ranging from inconspicuous camouflage to ostentatious sexual display, and can provide important information about the environment and biology of a particular organism. The most ubiquitous and abundant pigment, melanin, also has a diverse range of non-visual roles, including thermoregulation in ectotherms. However, little is known about the functional evolution of this important biochrome through deep time, owing to… 

Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur

The presence of blubber and distribution of melanophores in a countershading pattern in an Early Jurassic ichthyosaur demonstrate that the evolutionary convergence of these reptiles with extant marine amniotes extends to the cellular and molecular levels.

Biochemistry and adaptive colouration of an exceptionally preserved juvenile fossil sea turtle

The holotype (MHM-K2) of the Eocene cheloniine Tasbacka danica is arguably one of the best preserved juvenile fossil sea turtles on record and provides direct chemical evidence that adaptive melanism had evolved 54 million years ago.

Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils

It is shown that melanin is preserved in a number of soft-bodied fossils, but its burial under high pressure and temperature for millions of years alters its original chemistry, and it is argued that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils.

Interpreting melanin-based coloration through deep time: a critical review

Both vertebrate and microbial melanization are surveyed, and the conflicts influencing assessment of microbodies preserved in association with ancient animal soft tissues are explored, and an integrated morphological and geochemical approach for detecting endogenous pigment remains and associated microstructures in multimillion-year-old fossils is outlined.

Non-integumentary melanosomes can bias reconstructions of the colours of fossil vertebrates

It is shown that internal melanosomes that do not contribute to colour are abundant in some extant vertebrates and may redistribute during fossilization, necessitating caution in interpreting fossil colour.

Recent advances in amniote palaeocolour reconstruction and a framework for future research

This review focused on fossil amniotes produces an overarching framework that appropriately reconstructs palaeocolour by accounting for the chemical signatures of various pigments, morphology and local arrangement of pigment‐bearing vesicles, pigment concentration, macroscopic colour patterns, and taphonomy.


Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is

Reconstructing Carotenoid-Based and Structural Coloration in Fossil Skin

Taphonomic experiments resolve controls on the preservation of melanosomes and keratinous tissues in feathers

Fossils are a key source of data on the evolution of feather structure and function through deep time, but their ability to resolve macroevolutionary questions is compromised by an incomplete

Fossilization of melanosomes via sulfurization

The results reveal a high abundance of organosulfur compounds and non‐sulfurized fatty acid methyl esters in both the fossil tissues and host sediment; chemical signatures in the fossil tissue are inconsistent with preservation of phaeomelanin.



Molecular preservation of the pigment melanin in fossil melanosomes.

The presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark is demonstrated.

Plumage Color Patterns of an Extinct Dinosaur

This work has reconstructed the appearance of a theropod dinosaur by mapping features of its well-preserved feathers and comparing them with modern samples from birds, and indicates that the body was gray and dark and the face had rufous speckles.

Earliest fossil evidence for protective pigmentation in an actinopterygian fish

These markings provide the earliest evidence in primitive fossil actinopterygians for (respectively) countershading and the use of disruptive markings to break up the body outline, two of the most common protective coloration strategies in Recent fishes.


Comparative data on a nuclear gene in reptiles is provided and the utility of a candidate-gene approach for understanding the evolution of genes involved in vertebrate adaptation is highlighted.

The taphonomy of colour in fossil insects and feathers

Future studies focussing on key morphological and chemical aspects of colour preservation relating to cuticular Pigments in insects and keratinous structures and nonmelanin pigments in feathers will resolve outstanding questions regarding the taphonomy of colour and will enhance the ability to infer original colouration and its functions in fossil insects and theropods.

Thermal benefits of melanism in cordylid lizards: a theoretical and field test.

It is demonstrated that skin reflectance variation across cordylids has significant effects on their thermal balance, and studies investigating the role of varyingSkin reflectance in field populations and species should incorporate fine and broad temporal scales (daily, monthly, and seasonal), environmental variability, and cost-benefit trade-offs of thermoregulation.

Regulation of Body Temperature by Some Mesozoic Marine Reptiles

Data distribution reveals that these large marine reptiles were able to maintain a constant and high body temperature in oceanic environments ranging from tropical to cold temperate, and suggest high metabolic rates required for predation and fast swimming over large distances offshore.

Soft tissue preservation in a fossil marine lizard with a bilobed tail fin.

This fossil is reported from the Maastrichtian of Harrana in central Jordan, which preserves soft tissues, including high fidelity outlines of a caudal fluke and flippers, which provides the first indisputable evidence that derived mosasaurs were propelled by hypocercal tail fins.

Bone histology of aquatic reptiles: what does it tell us about secondary adaptation to an aquatic life?

It is shown that much remains to be done to better understand the relationship between histological features, growth rate and metabolism in extant taxa in order to make inferences in the fossil groups.