10Recreating Ancient Landscapes
‘ The re-creation of the vanished environment in which the dinosaur lived requires the same combination of artistic skill and application of scientific knowledge as does the restoration of the animal itself’.
The environments inhabited by our subject species deserve just as much consideration from artists as subject organisms (Fig. 10.1). Ancient landscapes – better referred to as palaeoenvironments – can be reconstructed in detail using sedimentological, stratigraphic (the layering of sedimentary rocks), palaeontological and geochemical data. Some of these fields might seem quite distant to artistry, and of little interest to those just wanting to draw fossil animals, but understanding the geological theory behind the formation of fossil-bearing rocks aids construction of interesting portrayals of extinct life. Just like extinct animals, ancient habitats have nuances and fine details that present unique creative opportunities to sharp-eyed artists, and appreciating the physical and biological mechanisms that buried our fossil subjects enhances our ability to understand their palaeobiology. Moreover, given that animal colour, integument and behaviour often reflects their habitats, knowing something of where they lived is a route to more credible restorations.
Fig. 10.1 Alice in Wonderland. Meticulously reconstructed palaeoenvironment of the ancient Alaskan Colville River showing ferns, cycads, monkey puzzle trees, Bennettitales, dawn redwoods, and Ginkgoes and flowering ginger plants. A female Nanuqsaurus hoglundi feels curiously small among such foliage. (Note that this is a complementary piece to Troodon in the Rushes, which explores the same setting, Fig. 2.15.) (R. Amos)
Any artwork that needs a landscape should consider palaeoenvironmental data early in the artistic process as it strongly influences composition, mood and tone. This should not only be the nature of the landscape, but also how we’re going to see it. All too often, palaeoart defaults to panoramic vistas of distant geographic features when a more intimate focus on a smaller area – like a forest floor or burrow entrance – might have made the artwork more successful (Fig. 10.2). Considering scope in this way allows us to direct our research: do we need to know about the large-scale geography and more conspicuous plants, or do we need to focus on a tighter setting, and research soils, small plants and tree roots? Having some real experience of natural habitats is useful here as it familiarizes us with the localized environments and microhabitats that make up grander, geologically-detectable settings, as well as encouraging us to look at how real landscapes are composed. There is an element of organized chaos to most habitats, particularly if they are well-vegetated, and bringing this to our artwork can avoid our landscapes looking sterile or artificial.
Fig. 10.2 Zhenyuanlong suni restored at the water’s edge. Portraying small sections of a palaeoenvironment aids the sense of location, realism, scale and character. (E. Willoughby)
Sedimentary rocks: the remains of ancient landscapes
Our main goal as palaeoartists is to understand the palaeoenvironment represented by a rock formation – a discrete unit of sedimentary rock that might represent several million years of depositional history, but represents a broadly similar habitat over that time. Formations are part of a ranking system of sedimentary rock layers – or ‘strata’ – that can become finer in scale (from formations down, we proceed to members and beds) or coarser (groups and supergroups), and these represent ever more specific or broader habitats. Members and beds are a little too restricted in scale to get an image of an overall environment; members might compose a river but not the floodplain, and beds represent single depositional events, often lacking broader environmental context in isolation. Above this, groups and supergroups are too large – they might represent a floodplain and neighbouring coastline, or shallow and deep seas, and accumulate over too long a period for precision understanding of their fauna and flora. For artists, formations are the palaeoenvironmental equivalent of Goldilocks’ porridge: not too specific, not too broad, but just the right amount of environmental information to give us context for our subject species.
The easiest and most reliable way to determine the palaeoenvironment represented by a formation is to check technical literature. Often, palaeontological papers describing new specimens or new species provide palaeoenvironmental data, sometimes under headings like ‘depositional settings’ or ‘geological context’. If they do not, or more detail is needed, the name of the formation yielding the species in question is typically provided and further research can continue from there. Ideally, artists should know at least the basic habitat type and details of the weather and climate before placing their subjects in a background.
Fig. 10.4 An example of a facies model, based on the Cretaceous Wessex Formation of southern Britain.
Palaeoenvironments are deduced by interpreting facies (Fig. 10.3). Facies are groups of sediment layers which represent specific depositional processes, such as the formation of a river meander or flood deposit, accumulation of deep sea muds, or construction of a sand dune. Different facies are combined into ‘facies models’, detailed predictions of ancient settings which incorporate data on not just what environments looked like, but also their climates, physical processes and interaction with the biosphere (Fig. 10.4). Facies models are very useful data for palaeoartists, but can be a little bewildering to novices because of their specialist terminology. A rough introduction to major facies groups is given below.
Upland facies
Upland settings are vulnerable to erosion and thus constitute only a small amount of the rock record. The most common upland facies are alluvial fans, which are rocky, sandy deposits created by canyon streams dropping sediment onto adjacent plains. These debris deposits indicate the proximity of highlands and can be crossed by streams and braided rivers (below).
Freshwater facies and their surroundings
Rivers are referred to as fluvial facies by geologists, and might be divided into braided (generally straight, bifurcating river channels, typical of highlands) or meandering (large, sinuous river channels typical of floodplains) systems. Fluvial facies often contain sediments representing breaches of the river margins, the most common of which are overbank deposits – sediments dropped by flood waters on ancient floodplains. Overbank deposits are important for artists as they tell us a lot about the habitats of many palaeoart mainstays such as dinosaurs, Cenozoic mammals and so on. Rare ancient soils (known as palaeosols) are indicative of abundant plant life in at least some parts of the floodplain. They may be associated with rhizocretions – remnants of roots that can, by their density and size, give an indication of how vegetated an environment was. Desiccation cracks might also be seen in overbank deposits, indicating periods of drought. Swamp or marsh facies are typified by abundances of organic particles, such as coal, and lacustrine facies represent ancient lakes. It is possible to determine details of circulation, depth, and water input into lacustrine systems, and these influence our choice of species, as well as their abundance, when restoring these settings.
Desert and other arid-habitat facies
Aeolian facies represent sediments carried and dropped by the wind – primarily deserts. They are dominated, as might be expected, by dune facies formed of red or orange oxidized sand, but also contain sabkha deposits (salt flats), desert lake facies (often surrounded by sabkhas) and interdune sediments. Interdunes are important for palaeoartists because their knack for accumulating water means they often attract life, including plants, big vertebrates, burrowing organisms and so on (Fig. 7.8).
Coastal facies
Most coastal facies have recognizable names: lagoonal, estuarine, beach, deltaic, tidal flat, and salt marsh, so their literature is a little more accessible to novices. But do not be fooled by this into thinking coastlines are easy to restore; on the contrary, they are complex settings which can often be understood in detail, and slapdash approaches to their reconstruction may lead to errors. If an artwork is to show the coastline of a specific formation – especially at large scale, such as in a panorama, it’s worth obtaining as much detail as possible to ensure the right environments are restored.
Marine facies
Although terrestrial animals hog most of the palaeoart limelight, rocks recording marine conditions are our primary sources of fossils and account for most of the sedimentary rock record (Fig. 10.5). Sands and muds representing fully marine conditions are especially common rock types. Marine sands often represent continental slope conditions, such as submarine fans (underwater equivalents of alluvial fans) or turbidites (underwater avalanches). Dark grey or black mudstones are typically representative of still, often oxygen-deprived settings at the sea bed. These are not thriving biological habitats but relatively dark, quiet environments where invertebrates burrowed through sediment looking for food, but other life was scarce (this is one reason why such rocks are so good at yielding fossils: biological remains that settled on these sea beds were largely undisturbed by scavengers). Note, however, that these are not equivalent to habitats found kilometres deep in oceans today: the sedimentary rock record mostly records sediments deposited in seas hundreds of metres deep, not thousands.
Fig. 10.5 Umoonasaurus demoscyllus and friends, depicted in a frozen southern coastal sea. We needn’t render marine scenes as empty blue backdrops: incorporating details of local geography and climate can add depth and interest to our work. (J. Egerkrans)
Fig. 10.6 Development of marine ecosystems over time. Reefs are an ancient biological phenomenon and offer interesting landscapes for marine palaeoart, but they have not always been made by corals – artists should ensure that their reef systems are suited to their position in geological time. Similarly, the dominant faunas of marine ecosystems, which might be visible in many palaeoartworks, have transformed over time. Simplified from Benton and Harper (2013).
Limestones – carbonate rocks – are predominantly composed of the calcium carbonate skeletons and shells of ancient organisms. Generating all these skeletons and shells requires a lot of productivity, and thus most carbonates are generated in warm, clear and often shallow settings where energizing sunlight can be accessed. The most famous types of carbonates are reefs, extensive, complex structures that influence surrounding conditions, generating related facies such as lagoons and slopes of accumulated sediment. Reefs have been constructed by different organisms over time and corals – or at least corals we might recognize – only took on this role in the Mesozoic period. Extinct types of coral, as well as brachiopods, bivalves and sponges have also played major roles as reef builders: artists should ensure that, if reefs are featured in their work, they are composed of their true architects (Fig. 10.6). Note that, while reefs since the Mesozoic have probably required light conditions to sustain photosynthetic corals, some more ancient reef builders were not reliant on light for nourishment and are not necessarily indicative of bright, well-lit waters. Not all limestone rocks are ancient reefs: shoals of carbonate pellets can be created in wave action in shallow waters, and chalk deposits form in relatively deep-water facies, created by oozes of deceased calcareous plankton that drifted down from sunlit waters above.
Geologists are often able to predict sea depth using geochemistry, sedimentology and palaeontological data. These results are important for artists as light and the influence of weather is variable within the water column, and the terminology used to explore these depths can also be a useful indication of habitat. The photic zone – where light penetration is sufficient for photosynthesis – ends at approximately 200m depth. Wave base – the depth to which wave energy influences the seabed – is typically described as fair weather and storm wave base. The depth of these is variable, but anything within fair-weather influence is very shallow – typically within 5–15m of the water surface. Storms, with their more powerful waves, can whip up seabeds of up to 30–125m deep, sometimes more.
Where animals live versus where animals fossilized
A complication to researching palaeoenvironments is that the place where animals lived is not always where their remains were buried and fossilized, so we must ascertain whether the palaeoenvironmental context of our subject fossils are appropriate to that species. Our enemy here is taphonomy – the physical and biological processes that influence animal remains between death and fossilization. Transportation of dead animal material is a common taphonomic process, and most typically reflects carcasses being floated or tumbled along in streams and rivers, washed away in floods, or set adrift at sea. This can transport animals far away from where they died, sometimes by hundreds of kilometres. Naturally, animal anatomy is a factor in how long they can survive being carried through different settings. Small, fragile species tend to fare poorly over long distances, while large, robust animals can travel quite far. Perhaps the champions of taphonomic transportation are the ankylosaurid dinosaurs. Upon death, their incredibly well-armoured hides became water-tight, scavenger-resistant sarcophagi, allowing them to float for miles before their remains finally sank. Ankylosaurs are often found in marine settings but not because they lived there: rather, it’s because their carcasses are so prone to prolonged transportation. A second factor which sees fossil animals fossilize in aberrant settings is their behaviour. Flying animals which normally live on floodplains or in woodlands can die crossing oceans, and terrestrial creatures can die en masse crossing rivers.
The best means to ascertain the palaeobiological significance of a depositional setting is to gain greater understanding of the subject animal and its relatives. Ankylosaurs, for instance, are not thought to be sea-going dinosaurs because their functional morphology does not suggest strong swimming capabilities, their diet is known to include a lot of non-marine plants, and their fossils – while sometimes found in ancient sea settings – are strongly biased towards continental palaeoenvironments. We can also look at fossil quality to estimate the likelihood of transportation before burial. Carcasses that have been on the move for a long time tend to fragment, particularly losing small and loosely jointed elements. Bodies moved over long distances are generally not articulated, complete specimens, and may even be reduced to just a portion of the original carcass. Thus, a couple of bones found in a habitat atypical for that clade may not be compelling evidence of the subject having lived in the place it was fossilized. A useful case study here concerns the often gigantic azhdarchid pterosaurs, creatures which have long defied agreement over their lifestyle and ecology. Some notable examples of these animals have been found in marine deposits, but analysis of the entire azhdarchid record showed that they were far more prevalent, and the fossils of better quality, in non-marine habitats (Witton and Naish 2008). It thus seems more sensible to render azhdarchids in terrestrial settings instead of marine ones. Conversely, another giant pterosaur, the famous Pteranodon, is known from over 1,000 specimens exclusively from marine formations, and many of which are very high quality (Bennett 2017). This indicates that Pteranodon probably spent a lot of its time flying over marine habitats, and that artists should bias our artwork appropriately.
Fig. 10.7 Principles of Walther’s Law, a useful concept for predicting habitats of fossil species found in unusual depositional contexts.
How can we tackle instances where subject species seem out of place? Ideally, we seek out a contemporary formation of suitable palaeoenvironment for our subject and assume it represents a reasonable model for its habitat, but this is not always possible. When so, our best bet might be to use an important geological rule known as Walther’s Law (Fig. 10.7). This is the simple but essential realization that, as environments move and grow over time (for example, as seas invade or recede from land, as deserts spread or shrink, as rivers shift their banks), their sedimentary record moves with them. New sediments deposited on top of old ones record new habitat types and, assuming there are no significant breaks in sediment accumulation, these new sediments will record the spread or recession of the neighbouring habitat type. Thus, a vertical stack of sediments (such as we might see in a cliff face) records a sequence of neighbouring environment types, and those neighbouring palaeoenvironments might be our best insight into habitats for a subject species found out of context. There are two caveats to employing Walther’s Law for palaeoart, however. The first is that sediments deposited before or after those holding our subject might be significantly younger or older than the time we are interested in, and environmental conditions may have changed in those intervening years. This is especially important when working close to major geological or biological events, like sudden climate shifts or extinctions, where conditions on one side of the event were likely drastically different to the other. The second caveat concerns the need for an unbroken depositional record. If sediments have a break in deposition – known as an unconformity – Walther’s Law does not work, because the continuity between shifting habitats is lost.
Still stuck? Seek help from fossils
Our creative process is frustrated when palaeoenvironmental interpretations are not available for our sediments of interest. If this occurs, fossils found alongside our subject species might throw some light on the likely environmental conditions. A lot of data can be gleaned from the invertebrate fauna of a rock unit because many have specific environmental tolerances. Creatures like echinoderms, cephalopods, brachiopods and so on are entirely marine, and photosynthetic creatures – like most corals and red algae – require shallow, well-lit marine conditions. Some molluscs and plants have strict freshwater or brackish (a condition between freshwater and marine salinity) tolerances (Fig. 10.8). We call these animals facies restricted, meaning that they are characteristic of certain facies (and by extension, specific habitat types). Vertebrates are less useful in this regard because many are mobile animals that can tolerant wide ranges of environments.
Fig. 10.8 Viviparus cariniferus, a Cretaceous freshwater snail. Animals such as this are key to predicting palaeoenvironmental conditions and, in lieu of more detailed analyses from sedimentologists, give palaeoartists a means to predict some elements of ancient habitats. (M. Witton)
Palaeoclimates
Physical environments create stages for our artwork, and the skies above are our backdrops. The sedimentary record itself contains a lot of climate data – structures such as mud cracks, mottling of mud rocks, depositional sequences of rivers, and clay mineral types tell us a lot about the availability of water in ancient settings. Fossils are also useful, with plant types, leaf shape and animal temperature tolerances (modelled using living species) giving insight into precipitation levels and temperature variance. But some of the best palaeoclimate data stems from isotopes in ancient shells, and this is something paleoartists can only access from researched literature. Collectively, these studies have produced long-term climate trends (Fig. 10.9) as well as providing insight into local climates and seasonality. Local climate conditions can contrast with contemporary global averages so, where possible, artists should attempt to find climate data for their formation (sometimes local climate studies are done at ‘group’ level, factoring data from several formations at once) instead of assuming the global norm. If climatic information is lacking, a few rough rules help roughly gauge climate conditions (Fig. 10.10). True crocodylians – the modern crocodile and alligator groups and their immediate fossil relatives – are restricted to relatively warm climates in the modern day and they are often used to infer warm conditions for ancient settings, too. It’s perhaps unwise to assume that all reptiles on the crocodylian evolutionary line reflect warm habitats because of uncertainty about the temperature tolerances of ancient species, but they are probably good guides for some Mesozoic and most Cenozoic habitats (Fig. 10.11). Different types of clay can also indicate the average temperature and moisture levels in different habitats. Evaporites – minerals created by dried out bodies of water – and mud-cracks are indicators of periodic aridity.
Fig. 10.9 Average global temperature throughout the Phanerozoic eon. These temperatures do not dictate climate conditions in all locations and habitats of a given time, but are useful data in lieu of more detailed climate models, as well as means to calibrate our basic assumptions of ancient climates. Mostly based on Benton and Harper (2013).
Fig. 10.10 Useful palaeontological and geological criteria for establishing temperature and humidity. Based on Benton and Harper (2013).
Fig. 10.11 Cretaceous Crocodyliformes such as Hulkepholis willetti are very crocodylian-like in anatomy and (presumably) lifestyle, and might be indicators of warm settings in the same way that crown-group Crocodylia can be. Whether this was true for all pseudosuchians is not certain, however. (M. Witton)
Populating landscapes with animals and plants
Our subject species did not exist in barren landscapes or seascapes, but communities shared with other organisms. Including accessory animals – a distant flock of birds or pterosaurs, a buzzing cloud of insects, a school of ammonites – can add depth, atmosphere and realism to a piece, as well as enhance the sense of location, habitat or geological time. Such species need to be duly researched before inclusion: though not the focus of the artwork, these animals have their own evolutionary history, geographic distribution, habitat preferences, anatomical configuration and so on that should be reflected accurately. Basing accessory animals on taxa from the same formation is a largely bulletproof means of ensuring there are no temporal or geographic hiccups but, where suitable information is lacking, artists might turn to the major faunal groups of their respective time period to provide ‘generic’ background species.
Fig. 10.12 Reconstruction of the insects, plants and weather conditions of the Cretaceous Crato Formation. These organisms are often background elements in palaeoart, but can be reconstructed in the same way as the charismatic fauna typical of mainstream palaeoart. (M. Witton)
Fig. 10.13 Alexander Island. A reconstruction of the ferns, conifers and geography of Cretaceous Antarctica, featuring Gingko trees, monkey puzzle trees, Taeniopteris, Aculea, Phyllopteroides, and a variety of cycads, ferns, tree ferns, and horsetails. A dinosaur is also featured (but you’ll have to look hard). (B. Nicholls)
Plants deserve a lot of consideration from palaeoartists (Figs. 10.12–10.13). They are not mere accessories in a scene, but often dominant, composition-defining elements in our artworks, transforming landscape topography and colour, as well as having a major effect on mood and tone. Unfortunately, although plants have an extensive fossil record, their remains are not always conducive with easy interpretation. Plants are often known by their seeds or spores rather than body fossils, and when we do find more visually-informative remains – roots, trunks and stems, leaves and flowers – they tend to be preserved as separate fossils. Palaeobotanists can only link these elements when fossils sharing these components are found, and otherwise have a difficult job putting plants back together. This is especially problematic in older deposits where now extinct plant lineages dominate, because modern species are of limited or no assistance in reconstructing their anatomy. Thanks to hard work and perseverance of palaeobotanists however, many now extinct varieties of Palaeozoic and Mesozoic plants have been reconstructed.
The quality of the plant fossil record echoes that of animals in being highly variable. Some formations have excellent, detailed insights into their floral communities, while others have very limited, if any, palaeobotanical data. Those formations with stronger records inevitably end up being the basis for settings where plants are less well known. In more recent deposits – particularly from the Mesozoic onwards – living plant species are often used as models for their fossil relatives. An important caveat about this method concerns the size and diversity of plant clades: plant groups – even genera – can be enormous, containing dozens or hundreds of species that can be radically different in basic morphology. Thus, a record of a certain plant type does not necessarily dictate our rendering of the most famous or familiar member of that species: we should use models that best match the morphological data and habitat requirements of the fossil example.
Fig. 10.14 Scotland in the Early Carboniferous, before the giant swamp forests that the Carboniferous is famous for have yet to appear. Tetrapodomorphs dot the landscape. (M. Witton)
Fig. 10.15 An overview of plant evolution. Note that plant lineages do not disappear once new ones evolve – although geological time has a succession of characteristic floras, we need not abandon older floral regimes each time a new flora develops.
Where data on floral communities is lacking, but there is good reason to think plants were present, palaeoartists must default to a general knowledge of suitable plants for the time and habitat of their subject artwork. The basic picture of plant evolution is well understood and allows us to recognise a succession of floral communities since plants colonized land in the Ordovician. This means we can roughly gauge appropriate vegetation for most palaeoartworks, but we must not oversimplify the story of plant evolution or skimp on augmenting our knowledge. For instance, many readers will be familiar with the geographically widespread lycopod swamps of the Carboniferous Period, but fewer may know that these are only common to later stages of the period – earlier Carboniferous landscapes lacked large forests or giant trees (Fig. 10.14). Similarly, a long-held Golden Rule of ‘no grass in the Mesozoic’ has been overturned in recent years: grasses were present and diverse in the Late Cretaceous, and in sufficient abundance for herbivorous dinosaurs to have eaten them (Prasad et al. 2005). While grasslands may have only become common from the Miocene onwards, artists have full licence to restore grasses in more ancient scenes. Much of our palaeoart research goes towards subject animals, but it is just as important to know something of ancient plants to generate credible palaeoart (Fig. 10.15).
General advice on reconstructing plants
Rendering ancient plants can be hampered by not only the broad issues outlined above, but also by a lack of accessible reference imagery of reconstructed plants. Palaeobotany textbooks can be useful here, and there are several available, but most illustrations – where included – are on the more diagrammatic end of illustration. There are, however, no end of useful books available on how to draw living plants, and these can help with translating the illustrations from textbook or scientific illustrations into realistic looking vegetation. Key things to pay attention to are branching patterns, leaf shape and plant size – ill-sized plants are the rue of many artworks trying to invoke a strong sense of scale.
Palaeoartworks often contain very neat landscapes, as if someone walked the scene before the artwork was executed to collect dead leaves and twigs, straighten the trees, and create neatly arranged pockets of vegetation between compacted, muddy surfaces. Truly wild habitats – not parks or woodlands carefully managed by humans for commercial or recreational use – are rarely like this. A rich array of plant matter in various states of decay are common to almost any area where plants are common, and vegetation has a most enterprising, opportunistic approach to growth that sees it adhere to unexpected surfaces, grow around obstacles and seek light at considerable expense. The roots and stems of plants become surfaces on which other, smaller plants (or plant-like organisms) grow – be this simple encrusters, like some mosses and lichens, or larger epiphytes, such as climbing plants and vines. A large plant can be an ideal and intriguing habitat itself for reconstructions of smaller animals. Some palaeoart critics are quick to assume that any area blanketed with low-lying greenery reflects grass, which may be inappropriate for many artworks. However, consider that many other plants – especially bryophytes (low-lying plants like mosses, hornworts and lycophytes), ferns and many types of angiosperm – are capable of carpeting wide areas in greenery today, and were presumably similarly adapted in the past.
