Maria Eithne McNamara

University College Cork | UCC · School of Biological, Earth & Environmental Sciences

Ancient biomolecules provide a unique perspective on the past but are underutilized in paleontology because of challenges in interpreting the chemistry of fossils. Most organically preserved soft tissues in fossils have been altered by thermal maturation during the fossilization process, obscuring original chemistry. Here, we use a comprehensive pr...

Fossil feathers have transformed our understanding of integumentary evolution in vertebrates. The evolution of feathers is associated with novel skin ultrastructures, but the fossil record of these changes is poor and thus the critical transition from scaled to feathered skin is poorly understood. Here we shed light on this issue using preserved sk...

The Eocene Geiseltal Konservat-Lagerstätte (Germany) is famous for reports of three dimensionally preserved soft tissues with sub-cellular detail. The proposed mode of preservation, direct replication in silica, is not known in other fossils and has not been verified using modern approaches. Here, we investigated the taphonomy of the Geiseltal anur...

Melanin pigments play a critical role in physiological processes and shaping animal behaviour. Fossil melanin is a unique resource for understanding the functional evolution of melanin but the impact of fossilisation on molecular signatures for eumelanin and, especially, phaeomelanin is not fully understood. Here we present a model for the chemical...

Fossil proteins are valuable tools in evolutionary biology. Recent technological advances and better integration of experimental methods have confirmed the feasibility of biomolecular preservation in deep time, yielding new insights into the timing of key evolutionary transitions. Keratins (formerly α-keratins) and corneous β-proteins (CBPs, former...

Many fossil insects show monochromatic colour patterns that may provide valuable insights into ancient insect behaviour and ecology. Whether these patterns reflect original pigmentary coloration is, however, unknown, and their formation mechanism has not been investigated. Here, we performed thermal maturation experiments on extant beetles with mel...

Pterosaurs evolved a broad range of body sizes, from small-bodied early forms with wingspans of mostly 1–2 m to the last-surviving giants with sizes of small airplanes. Since all pterosaurs began life as small hatchlings, giant forms must have attained large adult sizes through new growth strategies, which remain largely unknown. Here we assess win...

The Geiseltal biota is an Eocene lacustrine Konservat‐Lagerstätte in central Germany. Despite its rich fauna and flora (over 50 000 fossil vertebrates, insects and other invertebrates, plants and trace fossils) the taphonomy of the biota, and of the anurans in particular, is poorly understood. We analysed the skeletal taphonomy of 168 anurans, scor...

Colour patterning in extant animals can be used as a reliable indicator of their biology and, in extant fish, can inform on feeding strategy. Fossil fish with preserved colour patterns may thus illuminate the evolution of fish behaviour and community structure, but are understudied. Here we report preserved melanin-based integumentary colour patter...

Remarkably well-preserved soft tissues in Mesozoic fossils have yielded substantial insights into the evolution of feathers1. New evidence of branched feathers in pterosaurs suggests that feathers originated in the avemetatarsalian ancestor of pterosaurs and dinosaurs in the Early Triassic2, but the homology of these pterosaur structures with feath...

Background Sexual dimorphism is widespread in insects. The certain specialized structures may be used as weapons in male–male combats or as ornaments to enhance mating opportunities. Results We report striking swollen first tarsal segments in two families, four genera and six species of scorpionflies from the Middle Jurassic Yanliao Biota of North...

Fossil melanosomes are a major focus of paleobiological research because they can inform on the original coloration, phylogenetic affinities, and internal anatomy of ancient animals. Recent studies of vertebrate melanosomes revealed tissue-specific trends in melanosome-metal associations that can persist in fossils. In some fossil vertebrates, howe...

A key feature of the pigment melanin is its high binding affinity for trace metal ions. In modern vertebrates trace metals associated with melanosomes, melanin‐rich organelles, can show tissue‐specific and taxon‐specific distribution patterns. Such signals preserve in fossil melanosomes, informing on the anatomy and phylogenetic affinities of fossi...

Fossil melanosomes, micron-sized granules rich in melanin in vivo, provide key information for investigations of the original coloration, taxonomy and internal anatomy of fossil vertebrates. Such studies rely, in part, on analysis of the inorganic chemistry of preserved melanosomes and an understanding of melanosome chemical taphonomy. The extent t...

Extant weevils exhibit a remarkable colour palette that ranges from muted monochromatic tones to rainbow-like iridescence, with the most vibrant colours produced by three-dimensional photonic nanostructures housed within cuticular scales. Although the optical properties of these nanostructures are well understood, their evolutionary history is not...

Recent studies on the origin of feathers have been stimulated by discoveries of feather-like structures in various nonavian theropod dinosaurs from Late Jurassic to Early Cretaceous deposits in northeastern China. Filamentous integumentary structures are also known in two ornithischian dinosaurs from China, but whether these filaments form part of...

Terrestrial insects are often remarkably well preserved in lacustrine Konservat Lagerstätten. However, the assumption that carcasses should sink fast through the water column seems contradictory as this scenario is unlikely due to excessive buoyancy and surface tension. The mechanisms that promote rapid and permanent emplacement onto the sediment s...

Screening pigments are essential for vision in animals. Vertebrates use melanins bound in melanosomes as screening pigments, whereas cephalopods are assumed to use ommochromes. Preserved eye melanosomes in the controversial fossil Tullimonstrum (Mazon Creek, IL, USA) are partitioned by size and/or shape into distinct layers. These layers resemble t...

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 understanding of their taphonomy. Critically, the relative preservation potential of two key feather components, melanosomes and keratinous tissue, is not ful...

Significance Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemi...

The Eocene Geiseltal Konservat-Lagerstätte (˜47.5-42.5 million years) is hosted in lignites recovered from open mine pits located ca. 20 km SW of Halle (Saale), Saxony-Anhalt, Germany. Excavations began in the 1920’s and were terminated by the flooding of the pits in the 2000’s. Today, circa 50,000 specimens are curated in the Geiseltal Collection,...

Feathers have long been regarded as the innovation that drove the success of birds. However, feathers have been reported from close dinosaurian relatives of birds, and now from ornithischian dinosaurs and pterosaurs, the cousins of dinosaurs. Incomplete preservation makes these reports controversial. If true, these findings shift the origin of feat...

Pterosaurs were the first vertebrates to achieve true flapping flight, but in the absence of living representatives, many questions concerning their biology and lifestyle remain unresolved. Pycnofibres—the integumentary coverings of pterosaurs—are particularly enigmatic: although many reconstructions depict fur-like coverings composed of pycnofibre...

Scarab beetles (Coleoptera: Scarabaeidae) can exhibit striking colours produced by pigments and/or nanostructures. The latter include helicoidal (Bouligand) structures that can generate circularly polarized light. These have a cryptic evolutionary history in part because fossil examples are unknown. This suggests either a real biological signal, i....

The Middle–Upper Jurassic Yanliao Lagerstätte contains numerous exceptionally preserved fossils of aquatic and land organisms, including insects, salamanders, dinosaurs, pterosaurs and mammaliaforms. Despite extensive study of the diversity and evolutionary implications of the biota, the palaeoenvironmental setting and taphonomy of the fossils rema...

The soft tissues of many fossil vertebrates preserve evidence of melanosomes-micron-scale organelles that inform on integumentary coloration and communication strategies. In extant vertebrates, however, melanosomes also occur in internal tissues. Hence, fossil melanosomes may not derive solely from the integument and its appendages. Here, by analyz...

Melanosomes are important components of integumentary tissues in modern vertebrates and have been reported from various vertebrate and invertebrate fossils ranging in age from the upper Palaeozoic to the Cenozoic. Much previous work on vertebrate fossil melanin has focused on reconstructions of integumentary color. Modern vertebrates, however, also...

The lignite open mine pits at Geiseltal, located ca. 20 km SW of Halle (Saale), Saxony- Anhalt, Germany, have produced abundant and excellently preserved fossils for more than 80 years. A Konzentrat and Konservat-lagerstätte at the same time, the pits are flooded and inaccessible today. However, the Geiseltal Collection at the Center for Natural Sc...

Feathers are remarkable evolutionary innovations that are associated with complex adaptations of the skin in modern birds. Fossilised feathers in non-avian dinosaurs and basal birds provide insights into feather evolution, but how associated integumentary adaptations evolved is unclear. Here we report the discovery of fossil skin, preserved with re...

Lepidopteran scales exhibit remarkably complex ultrastructures, many of which produce structural colors that are the basis for diverse communication strategies. Little is known, however, about the early evolution of lepidopteran scales and their photonic structures. We report scale architectures from Jurassic Lepidoptera from the United Kingdom, Ge...

Melanosomes are important components of integumentary tissues in modern vertebrates and have been reported from various vertebrate and invertebrate fossils ranging in age from the upper Palaeozoic to the Cenozoic. Much previous work on fossil melanin has focused on reconstructions of integumentary colour in fossils. Modern vertebrates, however, als...

Geologic deposits containing fossils with remains of non-biomineralized tissues (i.e. Konservat-Lagerstätten) provide key insights into ancient organisms and ecosystems. Such deposits are not evenly distributed through geologic time or space, suggesting that global phenomena play a key role in exceptional fossil preservation. Nonetheless, establish...

[ Biol. Lett . 9 , 20130184. (Published online 27 March 2013) ([doi:10.1098/rsbl.2013.0184][2])][2] The methods section of the main text should state that the results reported are those of maturation experiments that were carried out for 1 h (not 24 h); feather morphology did not survive for 24 h

Melanosomes are important components of integumentary tissues in modern vertebrates and have been reported from various vertebrate and invertebrate fossils ranging in age from the upper Palaeozoic to the Cenozoic. Much previous work on fossil melanin has focussed on reconstructions of integumentary colour in fossils. Modern vertebrates, however, al...

Few fossil vertebrate skeletons are complete and fully articulated. Various taphonomic processes reduce the skeletal fidelity of decaying carcasses, the effects of most of which are reasonably well understood. Some fossil vertebrates, however, exhibit patterns of disarticulation and loss of completeness that are difficult to explain. Such skeletons...

Evidence of original coloration in fossils provides insights into the visual communication strategies used by ancient animals and the functional evolution of coloration over time [1-7]. Hitherto, all reconstructions of the colors of reptile integument and the plumage of fossil birds and feathered dinosaurs have been of melanin-based coloration [1-6...

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 incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origi...

The Lujiatun Unit (Yixian Formation) yields some of the most spectacular vertebrate fossils of the Jehol Group (Lower Cretaceous) of NE China. Specimens are preserved both articulated and three-dimensional, unlike the majority of Jehol fossils, which are near two-dimensional compression fossils. The site has been referred to as the ‘Chinese Pompeii...

Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties,...

Lingham-Soliar questions our interpretation of integumentary structures in the Middle-Late Jurassic ornithischian dinosaur Kulindadromeus as feather-like appendages and alternatively proposes that the compound structures observed around the humerus and femur of Kulindadromeus are support fibers associated with badly degraded scales. We consider thi...

Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been...

Middle Jurassic to Early Cretaceous deposits from northeastern China have yielded varied theropod dinosaurs bearing feathers. Filamentous integumentary structures have also been described in ornithischian dinosaurs, but whether these filaments can be regarded as part of the evolutionary lineage toward feathers remains controversial. Here we describ...

Fossil feathers often preserve evidence of melanosomes-micrometre-scale melanin-bearing organelles that have been used to infer original colours and patterns of the plumage of dinosaurs. Such reconstructions acknowledge that evidence from other colour-producing mechanisms is presently elusive and assume that melanosome geometry is not altered durin...

Colouration is an important multifunctional attribute of modern animals, but its evolutionary history is poorly resolved, in part because of our limited ability to recognize and interpret fossil evidence of colour. Recent studies on structural and pigmentary colours in fossil insects and feathers have illuminated important aspects of the anatomy, t...

Structural coloration underpins communication strategies in many extant insects but its evolution is poorly understood. This stems, in part, from limited data on how color alters during fossilization. We resolve this by using elevated pressures and temperatures to simulate the effects of burial on structurally colored cuticles of modern beetles. Ou...

The color of ancient organisms is typically elusive. This obscures the evolutionary history of the diverse colors and color patterns of modern animals. Recent synchrotron-X-ray-fluorescence (XRF) studies of fossil feathers have revealed chemical evidence of melanin, with significant implications for reconstructions of the original coloration and vi...

The colors of many animals arise from ordered nanometer-scale variations in tissue structure. Such structural colors—especially those with metallic optical effects—are widespread among modern insects but are preserved rarely in insect fossils. This suggests that a specific set of taphonomic circumstances is required for preservation of structural c...

The middle Miocene Rubielos de Mora Konservat-Lagersta¨tte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso-ventral aspect, the most hydrodynami...

The exceptional preservation of organisms is potentially influenced by various factors that reflect either the environmental context or aspects of the organisms' biology. There has been no systematic investigation of the relative impact of such factors upon the fidelity of preservation of an exceptionally preserved taxon. In this study, we present...

Conversion of wavelength data for predicted reflectance peaks to RGB values. (PDF)

Variation in observed color and in reflectance spectra of scales in media of different refractive index. (a, b) show the same area from the basal forewing of specimen MEI 14861. Scales appear yellow-orange when in glycerine (a) and blue in air (b). (c) Measured reflectance spectra of scales from the area shown in (a, b). Peak wavelength is 603 nm i...

Ultrastructure and predicted wavelength of Type A scales of different color and from different locations on the wing. (a, c, e) Transmission electron micrographs of scales from submarginal (a), postdiscal (c), and outer marginal (e) wing zones, and from the abdomen (g). Scales appear blue (a), green (b), brown (e), and yellow-orange (g) in glycerin...

Scanning electron micrographs of fossil lepidopteran forewing scales and wing membrane. (a) Basal region of Type A scale from discal zone of the wing, showing closely packed microribs and absence of windows. (b) Surface of brown non-metallic Type A scale from the outer margin of the wing, showing ridges, microribs, and perforations. (c) Transverse...

Ultrastructural details of scales exhibiting different colors and (in the case of intact individuals) from different parts of the forewing. (PDF)

Structurally colored lepidopteran fossils and forewing venation patterns. (a–d) Light micrographs of specimen MeI 11792 (a), MeI 14861 (b), MeI 641 (c), and MeI 11808 (d, e) (a coprolite). Note that the forewings are incomplete in MeI 11792. (e) shows detail of area indicated in (d). (f) Reconstruction of the forewing venation based on specimens Me...

Schematic reconstructions of the various scale types preserved in the fossil lepidopterans. (a) Type A scale showing longitudinal ridges (R) with transverse crossribs (C) and microribs (M) on the scale surface; the scale lumen comprises a stack of perforated laminae underlain by trabeculae (T). Note perforations (P) in, and bead-like and rod-like s...

List of specimens studied. (PDF)

Systematic paleontology; color and reflectance spectra of scales in media of different refractive index; preserved scale types and other ultrastructural features; and supplementary references. (DOC)

Structural colors are generated by scattering of light by variations in tissue nanostructure. They are widespread among animals and have been studied most extensively in butterflies and moths (Lepidoptera), which exhibit the widest diversity of photonic nanostructures, resultant colors, and visual effects of any extant organism. The evolution of st...