Vertebrate paleoecology: A current perspective

Vertebrate paleoecology, a study with a long history, has thrived during the last four decades and has become the focal point of intensive investigation since about 1965. It has followed a somewhat different course from studies of marine invertebrate paleoecology questions about the utility, validity and relationships of paleoecology to ecology continue to be raised and discussed.Paleoecology draws on and contributes to essentially all areas of paleontology. Several subdisciplines in which there has been particularly intensive investigation are singled out for discussion. Taphonomy lies at the base of all paleoecological studies for, along with systematic analysis, it provides the basic data upon which all reconstructions of the living biota are made from the fossil deposits to which they contributed. Very active in development of taphonomy have been the students of Paleoecology of the Hominidae. This area of study has passed from a dominance of speculation in the first decades of this century to objective analysis based upon the application of biological principles, extended and detailed field work, and current evolutionary concepts to the evolution of the family Hominidae.Extinctions have recently received extensive analyses, with emphasis on mass extinctions such as that at the Cretaceous-Tertiary boundary. The analyses have extended the uses of taphonomic research into the difficult areas of time intervals generally not available in the fossil record. Physiological-Ecological and Behavioral studies are casting new light upon the problems of interpretation of extinct animals which lack close living counterparts. Community Structure has been of special interest among terrestrial vertebrates since the early 1950's. It's study has required reinterpretations of samples and sampling procedures and development of models to aid in analysis of the biases in fossil assemblages. Both community types and substantive communities have received careful attention, including pragmatic definitions, studies of the use of analogies and introspection on possible contributions to ecology as whole. Such researches have been elaborated into studies of the relationships communities through time under the general heading of Community Evolution. Problems of evolution in a slowly changing community and in the evolution of new community types have been central themes in this area.     

Origin of brachiopod-bryozoan assemblages in an Upper Carboniferous limestone: importance of physical and ecological controls

Skeletal accumulations in the Upper Carboniferous Bird Spring Formation of southern Nevada have yielded new information regarding ecological succession in the fossil record and the development of shell concentrations. Through hydraulic baffling processes, a community dominated by cndobyssate bivalves and strophomcnid brachiopods was locally supplanted by a community composed primarily of bryozoans, compositid brachiopods, and various epizoans. The general trophic and diversity changes resemble those expected during 'short-term ecological succession' but are due for the most part to the sedimentological and hydraulic regime. In view of this evidence, previous paleontologic examples of 'autogenic' succession arc re-interpreted as having been primarily controlled by the physical environment. Upper Carboniferous, Brachiopoda, Bryozoa, paleoecology, ecological succession, epifauna.     

A fossil record for trematodes: extent and potential uses

Some extant parasitic flatworms (Phylum Platyhelminthes, Class Trematoda, Order Digenea) produce pits on the interior shell surface of their molluscan bivalve hosts. Based on comparisons of pits in Tertiary and Quaternary Gemma, Parastarte and Transennella (Family Veneridae), we establish a history of association between trematodes and these host genera spanning over 5 My in North America. This is the first report of a fossil record for the Trematoda. Similar pits are also present in many other bivalve genera (both fossil and living species), indicating that a substantial fossil record may exist for parasitic flatworms. The identification of parasitic infections from fossil shells may provide a new dimension for the study of the evolutionary biology, paleoecology and biogeography of host-parasite associations. □ Trematoda, trace fossils, Veneridae, paleoecology. life-history evolution, parasites.     

Paleoecology of benthic community replacement

The literature of community paleoecology is filled with examples in which long-term environmentally-controlled faunal transitions are misidentified as forms of ecologic succession. This has obscured a fundamental community-level process - community replacement - involving gradual to abrupt substitution of one benthic community for another as a result of subtle to sharp changes in habitats over subevolutionary time. In gradually changing environments, replacement takes place through conformational reorganization of species-abundance distributions within established communities, yielding sequences of slightly different fossil associations. Environments that change very rapidly drastically feature a different type of community replacement involving species turnover, wherein environmental tolerance limits of community members are closely approached or exceeded. Paleoecologists should be alert to the strong likelihood that many temporal transitions involving autochthonous fossil associations are, in fact, community replacement sequences.     

Uniformity in marine invertebrate ichnology

Relationships between ichnology and uniformitarianism are perhaps less complicated than those of their sister subdisciplines, paleontology and paleoecology. Trace fossils are manifestations of benthic behavior; and these traits, although evolving in significant ways, have remained stable over longer spans of time than individual species of invertebrates. The fossil record of behavior in fact originated earlier than the fossil record of invertebrate body parts. Although macroinvertebrates and their traces exhibit tremendous diversity of form and function, these fit into a relatively small number of behavioral patterns. The patterns, in turn, may correlate with prevailing environmental conditions, resulting in gradients among trace fossil assemblages, or ichnofacies. Behavioral patterns and characteristic ichnofacies therefore constitute the main basis for uniformity in ichnology. Thus, the most fundamental questions are: What is the specific function represented by the trace? How will it change as the tracemaker is influenced by other genetic, physiologic, or ecologic stimuli? In which facies will it likely occur? and what preservational biases are apt to modify the fossil record of this behavior and its environmental distribution? Approached from this standpoint, the present is indeed a key to the ichnologic past, and vice versa. In practice, however, the present has been studied considerably less than its importance would dictate.     

The ecostratigraphic paradigm

What can distinguish ecostratigraphy from other stratigraphic concepts stems not so much from its specific methods as from the theoretical background proposed here and called the ecostratigraphic paradigm. This theory claims that the fossil record of evolution at the community, taxocoene, and/or species group level displays a more or less discrete pattern, with discontinuities imposed mostly by extrinsic, geologic events. This pattern may constitute a base for natural stratigraphic classification of rocks using coenozonal schemes. The ecostratigraphic paradigm may or may not refer to communities as distinct and real biologic units. The greatest advantage of the ecostratigraphic approach is that the resultant set of time-planes is much more informative about the course of geobiologic evolution than the traditionally used chronostratigraphic one. Stratigraphial theory. ecostratigraphy. chronostratigraphy. paleoecology. coenozones. communities, evolution .     

The large-mammal fauna from the Kibish Formation

The Kibish faunal remains are useful for reconstructing the habitat of the earliest documented Homo sapiens and for understanding the community within which early modern humans existed. A diverse assemblage of large mammals, including many species of bovids, suids, and equids, has been recovered from the Kibish Formation. There are no extinct large mammals represented in the fossil assemblage, and the overall taxonomic composition of the fossil fauna is similar to the modern-day wildlife community living near the Omo River. The fossil faunal assemblage shows a paucity of arboreal primates, and carnivore species are rare. However, the faunal sample includes possible Cephalophus (duiker) remains and Hylochoerus meinertzhageni (giant forest hog), taxa that are extremely rare in the African fossil record, and both indicate more closed habitats. Comparative analyses of the Kibish faunal remains using the ecological-diversity approach document close associations with edaphic grassland and woodland vegetation types. These vegetation forms are similar to current habitats surrounding the Omo River.     

Plio-Pleistocene cercopithecids from Kanam East, western Kenya

This paper describes cercopithecid craniodental and postcranial fossils recovered by L. S. B. Leakey at Kanam East, Kenya during the early 1930s. These fossil monkeys have been generally assumed to have been derived from early Pliocene horizons, but their exact geographical and stratigraphical provenience is unknown. Although the question of the evolutionary significance of these specimens must await the recovery of more securely dated material from Kanam East, some general conclusions can be drawn concerning their taxonomic affinities and paleobiology. Based on comparative studies of the craniodental material, at least three extant genera are represented—Colobus,Lophocebus, andCercopithecus. The postcranial fossils include a number of hindlimb specimens, as well as the manubrium of a sternum and a caudal vertebra. Identification of the postcranial remains to particular genera is not possible, but they are similar in morphology to modern arboreal and semiterrestrial cercopithecid monkeys of small to medium size. It is evident that Kanam East had a diverse cercopithecid community, similar to those found today in forested and woodland habitats, and this may be of some significance in reconstructing the paleoecology of the site. Because the fossil record of most extant cercopithecid genera is rather sparse at Plio-Pleistocene sites in Africa, Kanam East represents one of only a few sites that has yielded material that can be assigned toColobus,Lophocebus, orCercopithecus. The fossil monkeys from the site, therefore, provide additional evidence to help reconstruct the paleobiology, as well as the patterns of species diversity and community structure that characterized the cercopithecid radiation during the Plio-Pleistocene.     

Boring Late Cambrian organisms

Specimens of inarticulate brachiopods (family Acrotrctidae) with boreholes were found in Upper Cambrian carbonates in the southern Great Basin of the United States. Some morphologic features and preferred orientation of the borings are similar to those made by predators and previously reported in the fossil and Holocene record. Such predatory activity on brachiopods is previously unknown in Cambrian rocks. Taxa associated with these specimens are not known to have been predators and identity of the predatory organism is unknown. Cambrian brachiopods, predation, paleoecology.     

Rangeomorphs,Thectardis (Porifera?) and dissolved organic carbon in the Ediacaran oceans

The mid-Ediacaran Mistaken Point biota of Newfoundland represents the first morphologically complex organisms in the fossil record. At the classic Mistaken Point localities the biota is dominated by the enigmatic group of "fractally" branching organisms called rangeomorphs. One of the few exceptions to the rangeomorph body plan is the fossil Thectardis avalonensis, which has been reconstructed as an upright, open cone with its apex in the sediment. No biological affinity has been suggested for this fossil, but here we show that its body plan is consistent with the hydrodynamics of the sponge water-canal system. Further, given the habitat of Thectardis beneath the photic zone, and the apparent absence of an archenteron, movement, or a fractally designed body plan, we suggest that it is a sponge. The recognition of sponges in the Mistaken Point biota provides some of the earliest body fossil evidence for this group, which must have ranged through the Ediacaran based on biomarkers, molecular clocks, and their position on the metazoan tree of life, in spite of their sparse macroscopic fossil record. Should our interpretation be correct, it would imply that the paleoecology of the Mistaken Point biota was dominated by sponges and rangeomorphs, organisms that are either known or hypothesized to feed in large part on dissolved organic carbon (DOC). The biology of these two clades gives insight into the structure of the Ediacaran ocean, and indicates that a non-uniformitarian mechanism delivered labile DOC to the Mistaken Point seafloor.     

Fossil bee nests,coleopteran pupal chambers and tuffaceous paleosols from the Late Cretaceous Laguna Palacios Formation,Central Patagonia (Argentina)

The Late Cretaceous Laguna Palacios Formation in Central Patagonia (San Jorge Basin), southern South America, is composed of tuffaceous deposits supplied by periodical volcanic ash falls partly reworked by rivers, on broad plains. Variations in ash-fall rates allowed the formation of stacked, mature paleosols, which are one of the most characteristic features of this formation. The mature paleosols show well-developed horizons, ped structure and bear an intricate network of trace fossils mostly produced by small roots and invertebrates. Two different insect trace fossils could be recognized in this formation: sweat bee nests and coleopteran pupal chambers. Fossil bee nests are composed of inclined tunnels with cells attached to them by means of short necks, a typical construction of bees of the subfamily Halictinae. Similar halictine constructions were reported from the Cretaceous of the USA. Coleopteran pupal chambers are discrete, ovoid structures, having an internal cavity with a smooth surface, and an outer wall of lumpy appearance composed of different layers of soil material. They are commonly constructed by the larvae of different families of Coleoptera. Similar trace fossils were previously reported from the Asencio Formation (Late Cretaceous–Early Tertiary) of Uruguay and from the Djadokhta Formation of Mongolia (Late Cretaceous). These trace fossils constitute some of the only paleontological data from the Laguna Palacios Formation, allowing inferences about its paleoecology, paleoclimatology and paleogeography. Ecological preferences of Halictinae, as well as some features of the nests, suggest a temperate, seasonal climate and an environment dominated by low vegetation for the Laguna Palacios Formation, which is also compatible with sedimentologic and pedogenic evidence. The morphology of the nests, typical of North American halictinae, adds more evidence to the hypothesis of the existence of faunal interchange between North and South America by the Late Cretaceous. The fossil nests constitute some of the oldest evidence of bees in the fossil record, the third known record of bees of Cretaceous age and the first for the Southern Hemisphere. The two traces described are, together with those of Dakota and the Gobi Desert, the only trace fossils from paleosols of Cretaceous age that can be certainly attributed to insects.     

Towards “A Natural History of Data”: Evolving Practices and Epistemologies of Data in Paleontology, 1800–2000

The fossil record is paleontology’s great resource, telling us virtually everything we know about the past history of life. This record, which has been accumulating since the beginning of paleontology as a professional discipline in the early nineteenth century, is a collection of objects. The fossil record exists literally, in the specimen drawers where fossils are kept, and figuratively, in the illustrations and records of fossils compiled in paleontological atlases and compendia. However, as has become increasingly clear since the later twentieth century, the fossil record is also a record of data. Paleontologists now routinely abstract information from the physical fossil record to construct databases that serve as the basis for quantitative analysis of patterns in the history of life. What is the significance of this distinction? While it is often assumed that the orientation towards treating the fossil record as a record of data is an innovation of the computer age, it turns out that nineteenth century paleontology was substantially “data driven.” This paper traces the evolution of data practices and analyses in paleontology, primarily through examination of the compendia in which the fossil record has been recorded over the past 200 years. I argue that the transition towards conceptualizing the fossil record as a record of data began long before the emergence of the technologies associated with modern databases (such as digital computers and modern statistical methods). I will also argue that this history reveals how new forms of visual representation were associated with the transition from seeing the fossil record as a record of objects to one of data or information, which allowed paleontologists to make new visual arguments about their data. While these practices and techniques have become increasingly sophisticated in recent decades, I will show that their basic methodology was in place over a century ago, and that, in a sense, paleontology has always been a “data driven” science.     

A new record of Gobius jarosi (Teleostei,Gobiidae) from the Early Miocene of Poland with inference to paleogeography and palaeoecology of the Carpathian Basin

Abstract

Gobies (family Gobiidae) were in the past and now important components of marine ecosystems as an essential part of the food chain. However, the early fossil record of this group is relatively meager, with only scarce skeletal remains. The oldest known representative of the genus Gobius has been recently described from the Early Miocene of Czech Republic as Gobius jarosi P?ikryl & Reichenbacher, 2018. Here we present a detailed study of a well-preserved goby skeleton of the same age from the Harta locality (Poland). This specimen is assumed as belonging to Gobius jarosi based on its almost complete morphological and meristic identity with the type material from the Vá?any nad Litavou locality. Some aspects of the paleogeography and paleoecology of the Early Miocene fish assemblage from Harta with special reference to the Carpathian Basin are also discussed in this paper.     

Increase of body size in sixgill sharks with change in diet as a possible background of their evolution

Body size variation of a predator is a simple way to follow the main changes in its food source during its life history or along its evolution in ecology and paleoecology, respectively. Here, we present possible first evidence of such predator-prey co-evolution through the study of the body size evolution among sixgill sharks (genus Hexanchus) inferred from their fossil record and by comparison to the life history of its two recent species. As for the observed ontogenic diet change of the living bluntnose sixgill shark (H. griseus), its ancestors appear to have developed a similar penchant for dining on marine mammals at the end of the Paleogene with a remarkably well-correlated timing.     

The Fossil Record of Vertebrate Tracks in Mexico

The fossil record of vertebrate tracks in Mexico is taxonomically rich and geographically diverse, and ranges in age from Middle Jurassic to Pleistocene and possibly Holocene. Middle Jurassic saurischian dinosaur tracks from Oaxaca represent the oldest record of vertebrate tracks in Mexico. Tracks attributed to Late Jurassic theropods and ornithopods are known from Michoacán. Theropod tracks of supposed Jurassic age are known from Durango. Lower Cretaceous Saurischian and ornithopod tracks are known from southern Puebla. Central Mexico has yielded Late Cretaceous hadrosaurid and sauropod tracks (Puebla), and tracks belonging to Theropoda and Ornithopoda (El Aguaje, Michoacan). In Coahuila several tracksites occur within the Cerro del Pueblo Formation and include tracks of mesoreptiles, pterosaurs, small to large theropods, bipedal and quadrupedal ornithopods, birds and possibly a mammal. A tracksite in the Olmos Formation includes tracks of turtles, crocodilians, medium-sized theropods, small ornithopods, and birds. Bird tracks of supposed Eocene age are known from Sinaloa. Two important Pleistocene ichnofaunas occur in the states of Puebla (Tepexi de Rodríguez) and Jalisco (San Juan de los Lagos), and include tracks of camelids, artiodactyls, small ungulates, elephants, large felids and birds. Pleistocene human tracks occur in Coahuila and Jalisco. Mexico's track record provides important insights into vertebrate diversity, paleoecology, and paleoenvironments. Given the rate of new discoveries since 1998, there is no doubt that new sites await to be found.     

Quantitative paleoecological analyses and implications of fossil assemblages of the Late Neogene Kangkou Limestone,Coastal Range,eastern Taiwan

The Late Neogene Kangkou and Tungho limestones of the Coastal Range of eastern Taiwan contain diverse fossil assemblages, but their paleoecology has not been quantitatively studied before. Cluster and non-metric multi-dimensional scaling (NMS) analyses were conducted using data from eight localities. Six fossil assemblages are recognized, with some overlap between them: Planktic Foraminifera (PF), Benthic Foraminifera (BF), Encrusting Foraminifera (EF), Bryozoan-Echinoderm-Algae-Mollusk (BEAM), Algae (A), and Coral (C) assemblages. The first two major axes of the NMS analysis can be interpreted as primarily representing water depth and substrate type. These assemblages represent various shallow marine settings with low to moderately high biodiversity.     

Variationsstatistik und Ökologie bei rezenten Foraminiferen

The variability in the characteristics of three recentBolivina-species in different environments has been statistically investigated with 6600 measurements. Bolivina argentea develops all transitions between slender and less sculptured types in low-oxygen basinwaters or broader, costate tests in watermasses, which are richer in their oxygen contents. Similar trends are indicated byBolivina pseudobeyrichi. Bolivina spissa develops slender forms in colder water exceeding 1000 meters in depth; whereas it creates broader and more sculptured tests in more shallow warmer water between 300 and 500 meters in depth. There is a gradual change between these two extreme-types in this case too. With the application of variation-statistics it has been possible for the first time to establish these ecotypical modifications with a sufficient degree of certainty. A direct application of the results in paleoecology doesn't seem to be justified in spite of several similar trends obtained with fossil foraminifers. By comparing the fossil relations with lithological data and indications from other elements of the fauna it should be possible to develop with variation-statistics a new important tool for the ecological interpretation of fossil sediments.     

Functional Morphology in Paleobiology: Origins of the Method of ‘Paradigms’

From the early nineteenth century, the successful use of fossils in stratigraphy oriented paleontology (and particularly the study of fossil invertebrates) towards geology. The consequent marginalising of biological objectives was countered in the twentieth century by the rise of ‘Paläobiologie’, first in the German cultural area and only later, as ‘paleobiology’, in the anglophone world. Several kinds of paleobiological research flourished internationally after the Second World War, among them the novel field of ‘paleoecology’. Within this field there were attempts to apply functional morphology to the problematical cases of fossil organisms, for which functions cannot be observed directly. This article describes the origins of the kind of functional inference for fossils that I proposed in 1961 as the method of ‘paradigms’ (a year before Thomas Kuhn made that word more widely familiar with a quite different meaning). Here I summarize some of my ‘worked exemplars’, which were intended to show the paradigm method in action. These case-studies were all taken from the paleontologically important phylum of the Brachiopoda, but the method was claimed to have much wider implications for the interpretation of the fossil record in terms of adaptive evolution. This article takes the history of the paradigm method as far as the late 1960s. I hope to trace, in a sequel, its ambivalent fate during the 1970s and beyond, when for example Gould’s critique of ‘the adaptationist programme’ and the rise of computer-based quantitative methods for the evolutionary interpretation of the fossil record led to the relative eclipse of functional morphology in paleontology.     

A new Old World vulture (Falconiformes: Accipitridae) from the Miocene of Gansu Province, northwest China

A large-sized and almost complete fossil vulture was discovered from the Late Miocene Liushu Formation of Linxia Basin in northwestern China. It is the best-preserved and the most complete fossil vulture yet discovered. The new genus and species Gansugyps linxiaensis is proposed and assigned to the family Accipitridae; morphology and limb proportions suggest it was chiefly an arboreal and soaring bird. It is more advanced than the other two known Miocene vultures from China. This new fossil increases our knowledge of the evolutionary history of vultures, and has implications for reconstructing the paleoecology of this region.     

The importance of fungi in shaping the paleoecosystem

Although fungi have a long geologic history, many aspects regarding their origins and subsequent evolution remain impossible to document from the fossil record. As heterotrophs, fungi must interact with other organisms, and it is here that the fossil record can provide an important source of biological and paleoecological information about fungal interactions. Saprophytic, parasitic and biotrophic interactions among fungi and other organisms are ancient; examples of these interrelationships are discussed as they relate to the establishment and evolution of the biological and physical paleoecosystem.