Herbivory in arthropods
Most of our knowledge of herbivory in arthropods comes from coprolites, feeding marks on leaves and other plant parts, wood borings sometimes containing coprolites , and inferences based on comparisons of fossils with their living counterparts. Plant-bearing arthropod coprolites are oval to cylindrical in shape and can be as much as 1 mm long, although most are smaller. Those that have been analysed contain the remains of various plant parts e.g. leaves, stems, spores, pollen derived from a...
Major Events in the History of Life
1.1.1 Origin of Life, 3 a. lazcano 1.1.2 Exploring for a Fossil Record of Extraterrestrial Life, 8 1.1.3 Life in the Archaean, 13 r.buick 1.1.4 Late Proterozoic Biogeochemical Cycles, 22 1.2.1 Metazoan Origins and Early Evolution, 25 d.h. erwin 1.2.2 Significance of Early Shells, 31 s. conway morris 1.2.3 Cambrian Food Webs, 40 n.j. butterfield 1.2.4 The Origin of Vertebrates, 43 m.p. smith and i.j. sansom 1.3.1 Ordovician Radiation, 49 a.i. miller 1.3.2 Rise of Fishes, 52 j.a. long 1.3.3...
Sediment chemistry
Non-biomineralized tissues display a spectrum of resistance to decay see Section 3.2.1 . At one end are robust structural tissues, such as arthropod cuticles and the seed coats and woody tissues of plants, which are decay resistant and may be incorporated into the fossil record as organic remains. At the other end are decay-prone tissues, such as muscle or gut, which degrade very rapidly they are only preserved when they are replicated very rapidly in authigenic minerals. Both organic and...
Biodiversity today
Estimates of the present diversity of life range over at least an order of magnitude, from perhaps 2-3 million species at the lower end, to 30-100 million at the upper end. The lower estimates represent summaries of the number of species that have actually been documented. It is estimated May 1990 , for example, that some 1.7-1.8 million species of modern microbes, plants, and animals have been named so far by systematists, and that figure must be a minimum estimate of current biodiversity....
Ancient cold seep communities
Fossiliferous ancient cold seep sites are found in similar tectonic settings to modern cold seeps, and they occur typically within deep-water siliciclastic or hemipelagic sedimentary sequences as discrete carbonate lenses with very negative 813C values and complex internal structures. These ancient cold seep fossil assemblages, like their modern equivalents, are more numerous and generally more species-rich than ancient hydrothermal vent communities Campbell and Bottjer 1995 . The Tertiary...
Nothofagus as an example of biogeographical patterns
Biogeographical patterns are best explained by example. The distribution of the Southern Hemisphere terrestrial biota during and following the fragmentation of Gond-wana is an interesting and complex case. There are no general examples, since every taxon has a unique history. However, some organisms probably give a better than average guide to the patterns and processes involved, and the angiosperm genus Nothofagus southern beech is one of these. Nothofagus is prominent in the biogeographical...
Preservation 1
Vertebrate fossils are abundant and some of the fish species occur in mass mortality events represented by bedding planes covered with myriad small fishes. Many specimens are preserved three-dimensionally and retain body cavities. The skeletons may be fully articulated, although many show geopetal collapse following decay of soft tissues. Phosphatized soft tissues occur abundantly within both vertebrates and invertebrates in the concretions at many sites around the basin. They were first noted...
Constraints imposed by bauplans
Raup's W-D-S-T morphospace Fig. 2.2.3.1 contains fields that are characteristic of particular taxonomic groups Raup 1966 . This results from a number of geometric and functional constraints bivalves and bra-chiopods need very high W to avoid the impairment of articulation that would result from prominent opposed Fig. 2.2.3.4 A two-dimensional morphospace for dichotomously branching structures, defined by the angle of the first dichotomy and the factor by which this angle changes in each...
History of tiering
Tiering is the vertical subdivision of space by organisms within a community, and the processes responsible for this organization include space, resources, and constructional constraints Ausich and Bottjer 1982 . The Phanerozoic history developed here is for suspensionfeeding communities on soft substrata, non-reef, shallow subtidal, and epicontinental environments. The tiering history represents the maximum characteristic tiering heights and depths within tier subdivisions. Clearly, not all...
New data Panderichthys Acanthostega Ichthyostega and others
Panderichthyids include Panderichthys Fig. 1.3.7.1b and Elpistostege Clack 1997 from the Frasnian of Latvia and Canada, respectively. They possess tetrapod-like dor-sally placed orbits, flattened skulls, enlarged ribs, fin distribution, and details of humeral morphology Coates 1996 . However, these apparently advanced characters are associated with primitive features such as a jointed braincase resembling the generalized sarcopterygian condition Carroll 1996 , and many key skeletal features...
Biota Ayy
The Rhynie biota comprises land plants, algae, fungi, a lichen, and bacterial mats, together with arthropods, which include a crustacean, trigonotarbid arachnids, a mite, and a collembolan springtail . Other material includes centipede fragments and a euthycarcinoid. The most abundant land plants are the spore-bearing sporophytes, which display an alternation of generations with sexual gametophytes. The small gameto-phytes of several plants have been described, in one case including the...
Predation and feathers
Discoveries in China have revealed that coelurosaurian theropods were feathered Ji et al. 1998 . Protarchaeo-pteryx and Caudipteryx had elongate, symmetrical feathers on the hands and tails Ji et al. 1998 . Surprisingly, these animals appear to be more primitive than dro-maeosaurs. This implies that, primitively, dromaeosaurs also had elongate symmetrical feathers on their hands see Fig. 4.1.13.1, point 5 . An examination of the hand of Deinonychus shows that feathers would not prohibit its...
Role in taphonomy
The filamentous network of microbial mats and their abundant production of mucilage favours the trapping not only of sediment particles but also of small organisms. This leads to the capture of planktic species as well as animals dead on the water surface. The organisms are then carried down to the floor of the aquatic environ ment as the mat sinks to the bottom. If bottom conditions are anoxic, they can be fossilized. Many localities where fossil insects are well preserved in finely laminated...
Origin and earliest fossil records of hexapods
The sparse fossil record of mid-Palaeozoic hexapods, the pattern of colonization of land by Palaeozoic plant and arthropod groups, and temporal constraints on hexapod origins imposed by hypotheses of arthropod phylogeny on hexapod origins all suggest that the earliest hexapods probably appeared during the Late Silurian. Although often used as a synonym for 'Insecta', the term 'Hexa-poda' designates the more inclusive clade that consists of the Collembola springtails and Protura proturans ,...
Bryozoans as a model system
Organisms that grow by budding morphologically variable but genetically homogeneous modules e.g. zooids within bryozoan colonies offer some special opportunities for the investigation of evolutionary tempo and mode. First, most characters whether metric, meristic, or coded behave as continuous variates, because zooids with different states of a character occur in varying proportions from colony to colony Cheetham 1987 . More significantly, breeding experiments with living bryozoan species have...
Origin of Primates
Whether the order Primates is restricted to extant forms and their undisputed extinct relatives Euprimates , or encompasses Plesiadapiformes as well, the origin of the group is enigmatic. The oldest euprimates appear abruptly in the fossil record in basal Eocene deposits of North America and Europe slightly later in Asia , with no clear indication of either their phylogenetic or geographical source. They seem to be part of an immigration event, also involving the ungulate orders Perissodactyla...
Inhumation burial by insects
Ants carry seeds to their nests where they may be buried in conditions suitable for germination. Special record, the Acacieae are few, and the important ant-dispersal syndrome in Australian Acacia probably evolved within the last 10 million years Murray 1986 . Seeds may be buried by dung beetles Scarabaeidae along with the dung. The oldest evidence of the scarabaeid dung-burying habit is Late Cretaceous see Collinson 1999 . Fig. 4.1.18.1 Fossil evidence for dispersal. a Devonian spore...
Results
The growth form of a variety of woody Palaeozoic species with secondary growth has been analysed, including Diaphorodendron vasculare, Pitus dayi, Lyginopteris oldhamia, and Calamopitys sp. Speck 1994 Speck and Rowe 1994 Rowe and Speck 1998 . In the first three plants the analysis was based on disconnected per-mineralized fragments from which a hypothesized ontogenetic sequence was constructed. With this type of data termed 'general data' by Rowe and Speck 1998 it is impossible to distinguish...
Identifying fossil bacteria
Bacteria in the Phanerozoic record are usually preserved by lithification. Their original organic matter is partly or wholly replaced by minerals, such as apatite, calcite, silica, pyrite, or siderite Liebig 1998a,b . Thus, fossil bacteria can be identified by their morphology, but their simple shape means that other criteria must be used to distinguish them from similar non-bacterial structures. Characteristic features of bacteria are their size and shape, cellular division, association,...
Are morphospecies adequate
In the punctuated equilibria model, a species remains static for virtually all of its duration, typically millions of years, following the comparatively brief interval of change associated with its origin. Thus, stasis is a long-term phenomenon requiring palaeontological data for its identification. Inevitably, the question of whether biological species can be recognized in the fossil record is raised Levinton 1988 . Fossil species are morphospecies, for the most part based on preservable...
Biogeographical processes
If an organism is spatially distributed in a way that warrants explanation, there must have been dispersal events, where organisms presumably migrated across pre-existing barriers, and or vicariance events, where the formation of barriers fragmented the ranges of once continuously distributed species. These alternatives represent past events that cannot be directly observed. For each case examined, data must be gathered to test hypotheses formulated to explain current distributions. These data...
Cuticle chemistry and structure
The epicuticle consists of cuticular waxes, which are composed mainly of straight chain and branched hydrocarbons, wax esters, fatty acids, alcohols, ketones, and sterols e.g. cholesterol , and function in preventing dehydration. The rest of the cuticle is composed mainly of two biopolymers, chitin and protein, which form a complex structure cross-linked by catechol, aspartic, and or histidyl moieties Briggs et al. 1998 . Chitin, a nitrogen-containing polysaccharide, provides the structural...
Introduction Vxt
Grass-dominated ecosystems, and those where grasses make up a significant fraction of the flora, are globally widespread. Tropical savannahs make up more than half the land area at low latitudes, and grass-dominated ecosystems are abundant in parts of North America and central Asia. Modern grasses use two different photo-synthetic pathways, the more ancient 'C3 pathway' and the more recent 'C4 pathway', where 'C3' and 'C4' refer to the number of carbon atoms in the first product during CO2...
Pack hunting behaviour in dromaeosaurs
Fossil evidence supports the possibility of pack hunting behaviour in dromaeosaurs when they were attacking prey significantly larger than themselves. Deinonychus teeth and body fossils are frequently found associated with a single Tenontosaurus, an ornithischian two or more times the size of Deinonychus Maxwell and Ostrom 1995 . Multiple Deinonychus would have leaped at the tenontosaur and employed the forelimb attack. An analogy for the attack of a single Deinonychus during the fray is the...
Ancient hydrothermal vent communities from other tectonic settings
Fossil assemblages have been found in a number of Palaeozoic sediment-hosted sulphide and barite deposits. These are interpreted as representing low temperature hydrothermal vent sites within sedimentary systems some are possible ancient analogues of modern sedimented vent sites, like those in the Gulf of Mexico. Carboniferous examples include carbonate mounds with sulphide mineralization from Newfoundland, containing low-diversity, high-abundance faunas of brachiopods, trepostome bryozoans,...
Pelagic trilobites
There is a convincing functional morphological case that some telephinid and cyclopygid trilobites were pelagic Fortey 1985 . These planktic trilobites apparently descended to the sea floor to moult see Whittington 1992 . Flume tank experiments suggest that Parabarran-dia may have been nektonic, based on its streamlined form Fortey 1985 . Hypotheses that small or spinose trilobites were pelagic or epipelagic are usually unconvincing when functional morphology, taphonomy, and stratigraphic...
Introduction Izd
Living primates include monkeys, apes, and humans grouped as anthropoids , and their primitive cousins the lemurs, lorises, and tarsiers prosimians . This arrangement is gradistic but only partly phylogenetic Anthropoidea are considered monophyletic, whereas prosimians are not. Consequently, many authorities employ the cladistic terms Strepsirrhini for lemurs lorises Lemuriformes , and Haplorhini for Tarsi-iformes Anthropoidea Fig. 1.5.4.1 . A sister-taxon relationship between tarsiers and...
Mammaliaforms and mammals
The earliest true mammals are known from the Late Tri-assic Norian , about 210Ma. Appearing somewhat earlier are what might be called near-mammals, creatures which in life probably looked like mammals but which lie phylogenetically outside the Mammalia as currently defined the common ancestor of monotremes, marsupials, and placentals and its descendants McKenna and Bell 1997 . The near-mammals are placed in a more inclusive taxon Mammaliaformes, which includes Mammalia plus the Late Triassic...
Dissociated heterochrony
The role of peramorphosis in generating increase in body size by either hypermorphosis or acceleration suggests that Cope's Rule the trend of phylogenetic increase in body size may have its origins in peramor-phosis. Studies of lineages of Jurassic bivalves and ammonites Hallam 1975 demonstrated that almost all showed trends to increased body size. Similar patterns are evident in foraminifers, primates, and other mammals McKinney in McNamara 1990 . One consequence of peramorphosis involving...
Palynoecological fingerprints
Pollen grains are subjected to corrosion and degradation in the interval between aeolian deposition and excretion by soil organisms. During the complex cycle of consumption, excretion, and decay of organic matter by the soil fauna, pollen grains and spores are subjected to intensive mechanical damage. Soil pollen spectra are useful ecological 'fingerprints' for archaeological and landscape-ecological studies. The contrast between the pollen-producing species represented in spectra following the...
Palaeoenvironment
The Romualdo Member yields as many as 25 species of fishes, but turtles, crocodiles, pterosaurs, and dinosaurs are also present Martill 1993 . Invertebrates are less diverse but include the ostracod Pattersoncypris micropa-pilosa in superabundance, larvae of portunid crabs, small shrimp-like crustaceans, and molluscs including corbu-lid bivalves and several small gastropods . Coprolites are very common and are often rich in small fish bone inclusions. Plants include horsetails, ferns, cycads,...
Palaeoecological approaches
Palaeoecological data that are used for the reconstruction of biotic recoveries after mass extinctions include palaeocommunity and biofabric information as well as taxonomic data with an ecological component. Such data are not easily extracted from literature or museum collections and generally require new field studies. Important concepts include the following 1 Opportunists Fig. 2.3.10.1 are taxa that undergo a dramatic increase in abundance during the recovery interval Hallam and Wignall...
References Dog
Briggs, D.E.G., Rolfe, W.D.I. and Brannan, J. 1979 A giant myriapod trail from the Namurian of Arran, Scotland. Palaeontology 22, 273-291. Johnson, E.W., Briggs, D.E.G., Suthren, R.J., Wright, J.L. and Tunnicliff, S.P. 1994 Non-marine arthropod traces from the subaerial Ordovician Borrowdale Volcanic Group, English Lake District. Geological Magazine 131, 395-406. Manton, S.M. 1977 The Arthropoda habits, functional morphology and evolution. Oxford University Press, Oxford. Osgood, R.G. 1970...
Multiple impacts hypothesis
Multiple impacts of asteroids or comets on the Earth have been proposed as an alternative to glaciation as a mechanism for producing pulses of global cooling McGhee 1996 . The Late Devonian does seem to have been a time of increased impact frequency, in that from 6 to 10 known terrestrial impact craters are currently thought to be of Late Devonian age. Two of these, the Siljan crater in Sweden and the Charlevoix crater in Canada, are definitely of Late Devonian age and are quite large 52 km and...
Geographical selectivity
Geographical extinction selectivity occurs because most catastrophic events, as well as more frequent background disturbances, do not influence all regions with equal magnitude. Both background and mass extinction rates vary among geographical biotas Flessa and Jablonski 1996 . Geographical selectivity may also cause taxonomic selectivity Fig. 2.3.9.1 because related species tend to be found in geographical proximity Gaston and Blackburn 1997 . Three basic categories of habitats are often...
Heterochrony and evolutionary trends
Heterochrony also plays an important role in evolutionary trends. These trends can be either anagenetic or cladogenetic, and within or between species McNamara 1990 . The relationship between evolutionary trends and heterochrony arises because, by their very definition, trends are unidirectional, in much the same way as are ontogenetic trajectories. However, for trends to develop, extrinsic factors are also critical, in addition to the intrin sic factor of heterochrony. Selection of either...
Early vertebrate relationships
The application of phylogenetic cladistic analysis has greatly facilitated the appraisal of evolutionary relationships amongst early vertebrates Fig. 1.2.4.3a . Despite this, published cladograms remain relatively unstable in comparison with those derived for higher vertebrate groups and it is probable that this will continue to be the case for some time. Nevertheless, the recent recovery of microvertebrates from Cambrian and Ordovician strata, together with the increasing quantity of soft...
Bioimmuration
P.D. TAYLOR and J.A. TODD Introduction Bioimmuration is preservation due to organic overgrowth. The term has been applied to both the process and the product. Bioimmuration is an important yet scarcely studied mode of fossilization which is capable of preserving sessile organisms without mineralized hard parts in ordinary depositional settings. A simple example of bioimmuration is the formation of an imprint external mould of a soft-bodied hydroid on the shell attachment area of an oyster which...
Fossil saprobic and parasitic fungi
Within the Rhynie chert are abundant examples of partially decomposed and degraded plant material that reflect the activities of various saprobes. Although hyphae and spores are easily distinguished within plant tissues Fig. 4.2.9.1a , it is difficult to determine which fungi were responsible for these saprophytic activities. Within the chert are numerous chytridiomycetes, a group of fungi that today includes mainly freshwater saprobes of algae, various microscopic animals, land plants, and...
Marine bioeroding organisms
There are three major types of marine bioeroding organisms microborers, internal macroborers, and external raspers or scrapers Table 3.2.2.1 . Microborers are primarily filamentous endolithic algae and fungi. Macro-borers do not eat their host substrates, but excavate dwellings within them, where they are protected from predation. The relative importance of microboring, mac-roboring, and grazing varies with depth, sedimentation rate, and productivity. Boring sponges excavate their substrates by...
Timing of angiosperm origin and their first major radiation
The earliest angiosperm remains that can be recognized with certainty in the fossil record are dispersed, monoaperturate pollen grains with a reticulate-columellate outer pollen wall very similar to the pollen Fig. 1.4.2.3 Structural features of angiosperms leaves, wood, pollen . a Leaf of Cercidiphyllum with hierarchical reticulate venation. b,c Vessel elements of angiosperm wood. d,e Angiosperm pollen with reticulate-columellate pollen wall d monoaperturate grain of monocotyledon e tricolpate...
PalaeoCO reconstructions from fossil stomata
Quantitative palaeo-CO2 estimates for the Cenozoic have been made from fossil stomatal characteristics, using calibrations of stomatal density and index responses of nearest living relative NLR species to known concentrations of atmospheric CO2. This methodology cannot be applied to Mesozoic and Palaeozoic CO2 reconstruction, as extant species of vascular plants are not known earlier than the Late Tertiary. The stomatal parameters of these extinct pre-Tertiary fossil plants are therefore...
A classification of timeaveraged assemblages
Fossil assemblages can be classified according to their degree of time-averaging Kidwell and Bosence 1991 . The categories are somewhat arbitrary, inasmuch as they divide up a continuous spectrum of time-averaging. Nevertheless, they are of value in providing guidelines for understanding the origin of fossil assemblages 1 Ecological snapshots are fossil assemblages that accumulated with little or no time-averaging. Specimens are likely to be ecologically compatible, well preserved, articulated,...
EndPermian mass extinction and Triassic recovery
The end-Permian is the greatest of all Phanerozoic mass extinctions e.g. Sepkoski 1981 see Section 2.4.4 . The aftermath of this mass extinction lasted throughout the Early Triassic see Section 2.3.10 . A variety of palaeoeco-logical data from Lower Triassic marine strata can be used to assess this event in terms of palaeoecological levels. Ecospace was to a large extent emptied by the end-Permian mass extinction see Sections 2.3.10 and 2.4.4 . Of the possible Bambachian megaguilds, only five...
Bioerosion rates and succession in bioeroding organisms
Microborers are usually the first bioeroding organisms to colonize fresh substrates, and can cover 50 of fresh carbonate material in 2 months. As soon as endolithic algae accumulate significant biomass, grazers initiate external bioerosion, typically within 6 months grazing bioerosion accounts for 70-90 of total bioerosion on many coral reefs Glynn 1997 . Grazing activity restricts internal macroborer bioerosion by removing larvae and juveniles of boring sponges and bivalves. Macroborer...
Metazoan Origins and Early Evolution
The nature of the origin and early evolution of animals remains among the great conundrums of the history of life, despite incredible advances over the past decade. New fossil discoveries, a dramatically improved time scale, exciting new views of the relationships between major metazoan groups based on both molecular and morphological data, and a wealth of information from comparative studies of the developmental process have all contributed to our growing understanding of events during the...
Terrestrialization
The first records and ranges of all fossils thought relevant to terrestrialization are documented in Fig. 1.3.4.1. 1 Obligate permanent tetrads are so named because they do not split into four spores monads on dispersal. They possess durable, smooth, unornamented walls, thought to be impregnated with sporopollenin although this has not been chemically proven . Some are enclosed within a smooth or ornamented resilient envelope 'membrane' . Both forms are common in Llanvirn to late Llandovery...
Increases in ecospace utilization tiering adaptive strategies and guilds
Marine invertebrates have utilized more and more eco-space through the Phanerozoic such increases, in part, correspond with the appearance of each of the three successive Evolutionary Faunas Sepkoski 1981 . Bambach 1983 introduced 'adaptive strategies' as a means of evaluating palaeoecological changes through time e.g. Fig. 4.2.1.1 . These are defined by life position e.g. mobile epifauna and general feeding type, and they include, for example, categories such as epifaunal mobile suspension...
Proterozoic Lagersttten
In contrast to that of the Archaean, the palaeontological record of Palaeoproterozoic and Mesoproterozoic life is abundant and well preserved Knoll 1996 . Preservation is especially good in silicified tidal flat carbonates characterized by syndepositional lithification and, at least locally, sea-floor carbonate precipitation. Mat-building populations of entophysalid cyanobacteria are preserved along with short oscillatorian trichomes and in some cases elongate akinetes, the resting stages of...
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Fig. 4.1.6.2 Selected arthropod trackway ichnotaxa attributed to trilobites a,b , Habelia optata c , crustaceans d , arthropleurids e , insects f-h , and chelicerates i-l . a Cruziana semiplicata. b Petalichnus brandenburgensis. c Angulichnus alternipes. d Umfolozia sinuosa. e Diplichnites cuithensis. f Siskemia bipediculus. g Permichnium voelckeri. h Lithographus hieroglyphicus. i Kouphichnium variabilis. j Palmichnium antarcticum. k Paleohelcura tridactyla. l Octopodichnus didactylus. Scale...