The high fidelity of the cetacean stranding record: insights into measuring diversity by integrating taphonomy and macroecology

Stranded cetaceans have long intrigued naturalists because their causation has escaped singular explanations. Regardless of cause, strandings also represent a sample of the living community, although their fidelity has rarely been quantified. Using commensurate stranding and sighting records compiled from archived datasets representing nearly every major ocean basin, I demonstrated that the cetacean stranding record faithfully reflects patterns of richness and relative abundance in living communities, especially for coastlines greater than 2000 km and latitudinal gradients greater than 4°. Live-dead fidelity metrics from seven different countries indicated that strandings were almost always richer than live surveys; richness also increased with coastline length. Most death assemblages recorded the same ranked relative abundance as living communities, although this correlation decreased in strength and significance at coastline lengths greater than 15,000 km, highlighting the importance of sampling diversity at regional scales. Rarefaction analyses indicated that sampling greater than 10 years generally enhanced the completeness of death assemblages, although protracted temporal sampling did not substitute for sampling over longer coastlines or broader latitudes. Overall, this global live-dead comparison demonstrated that strandings almost always provided better diversity information about extant cetacean communities than live surveys; such archives are therefore relevant for macroecological and palaeobiological studies of cetacean community change through time.     

Caught in the act: the first record of copulating fossil vertebrates

The behaviour of fossil organisms can typically be inferred only indirectly, but rare fossil finds can provide surprising insights. Here, we report from the Eocene Messel Pit Fossil Site between Darmstadt and Frankfurt, Germany numerous pairs of the fossil carettochelyid turtle Allaeochelys crassesculpta that represent for the first time among fossil vertebrates couples that perished during copulation. Females of this taxon can be distinguished from males by their relatively shorter tails and development of plastral kinesis. The preservation of mating pairs has important taphonomic implications for the Messel Pit Fossil Site, as it is unlikely that the turtles would mate in poisonous surface waters. Instead, the turtles initiated copulation in habitable surface waters, but perished when their skin absorbed poisons while sinking into toxic layers. The mating pairs from Messel are therefore more consistent with a stratified, volcanic maar lake with inhabitable surface waters and a deadly abyss.     

Infaunal augurs of the Cambrian explosion: An Ediacaran trace fossil assemblage from Nevada,USA

Morphologically complex trace fossils, recording the infaunal activities of bilaterian animals, are common in Phanerozoic successions but rare in the Ediacaran fossil record. Here, we describe a trace fossil assemblage from the lower Dunfee Member of the Deep Spring Formation at Mount Dunfee (Nevada, USA), over 500 m below the Ediacaran–Cambrian boundary. Although millimetric in scale and largely not fabric‐disruptive, the Dunfee assemblage includes complex and sediment‐penetrative trace fossil morphologies that are characteristic of Cambrian deposits. The Dunfee assemblage records one of the oldest documented instances of sediment‐penetrative infaunalization, corroborating previous molecular, ichnologic, and paleoecological data suggesting that crown‐group bilaterians and bilaterian‐style ecologies were present in late Ediacaran shallow marine ecosystems. Moreover, Dunfee trace fossils co‐occur with classic upper Ediacaran tubular body fossils in multiple horizons, indicating that Ediacaran infauna and epifauna coexisted and likely formed stable ecosystems.     

Body size of insular carnivores: evidence from the fossil record

Aim Our goals here are to: (1) assess the generality of one aspect of the island rule – the progressive trend towards decrease in size in larger species – for fossil carnivores on islands; (2) offer causal explanations for this pattern and deviations from it – as far as fossil carnivores are concerned; and (3) estimate the speed of this trend. Location Oceanic and oceanic‐like islands world‐wide. Methods Body size estimates of fossil insular carnivores and of their phylogenetically closest mainland relative were obtained from our own data and the published literature. Our dataset consisted of 18 species from nine islands world‐wide. These data were used to test whether the body size of fossil insular carnivores varies as a function of body size of the mainland species in combination with characteristics of the island ecosystem. Results Dwarfism was observed in two canid species. Moderate decrease in body mass was observed in one hyena species. Gigantism was observed in one otter species. Moderate body mass increase was observed in two otter species, one galictine mustelid and perhaps one canid. Negligible or no change in body mass at all was observed in five otter species, three galictine mustelids and one genet. Size changes in teeth do not lag behind in comparison to skeletal elements in the dwarfed canids. The evolutionary speed of dwarfism in a canid lineage is low. Main conclusions Size change in fossil terrestrial insular carnivores was constrained by certain ecological conditions, especially the availability of prey of appropriate body size. When such alternative prey was not available, the carnivores retained their mainland size. The impact of competitive carnivores seems negligible. The case of (semi‐)aquatic carnivores is much less clear. The species that maintained their ancestral body mass may have changed their diet, as is evidenced by their dentition. Among the otters, one case of significant size increase was observed, perhaps best explained as being due to it entering the niche of an obligate aquatic otter. Dwarfism was not observed in otters. The island rule seems to apply to fossil carnivores, but with exceptions. The dependency of the island rule on resource availability is emphasized by the present study.     

Species,genera, and phylogenetic structure in the human fossil record: a modest proposal

Because of the greater morphological distances among them, genera should be more robustly recognizable in the fossil record than species are. But there are clearly upper as well as lower bounds to their species inclusivity. Currently, the vast majority of fossils composing the large and rapidly expanding paleoanthropological record are crammed into one of two genera (Australopithecus vs Homo), expanding the latter, especially, far beyond any reasonable morphological or phylogenetic limits. This excessive inclusivity obscures both diversity and the complexities of phylogenetic structure within the hominid family.     

Field sampling bias, museum collections and completeness of the fossil record

Museum specimens, particularly old collections, typically lack comprehensive field data and determination of substrate, sampling biases, etc., is problematic. Diversity at the generic level of all identifiable latest Cretaceous (Campanian–Maastrichtian) echinoderm remains in major museum collections from the Mons (southern Belgium) and Danish (Jylland (Jutland) and Sjælland (Zealand)) basins were compared to those of the Liège-Limburg Basin. The last-named has been studied in detail, including microscopical analysis of ossicles picked from bulk samples. Echinoids of the Mons Basin show similarities to those of the Liège-Limburg Basin, but crinoids, asteroids and ophiuroids remain poorly known from the former. Echinoderms of the Danish Basin resemble those of similar chalk lithofacies in the Liège-Limburg Basin, despite significant geographical separation. These disparities can be explained, at least in part, by collector bias in sampling methodology, although differences in substrate presumably also had an influence.     

Giant ants from the Paleogene of Denmark with a discussion of the fossil history and early evolution of ants (Hymenoptera: Formicidae)

Pachycondyla rebekkae sp. nov. (Formicidae, Ponerinae) is described from the Fur and Ø1st Formations (transitional between Paleocene and Eocene, Denmark). About 95 complete or fragmentary gyne specimens and one almost complete male specimen were examined, revealing characters which permit classification and placement of the fossil species in the phylogenetic system of extant Formicidae. The palaeoecology and taphonomy of the insect fauna of the Fur and Ø1st Formations are discussed. Finally, the significance of the new species is discussed in light of the fossil history and early evolution of ants.     

Morphological design and fossil record of the podocopid ostracod naupliar eye

The naupliar eye of podocopid ostracods is a useful character for considering evolution in photic environments. Based on external morphologies and histological observations, naupliar eyes are here categorized into six types. The fossil record demonstrates that the major evolutionary changes in podocopid naupliar eyes occured after the Ordovician. Eye types 1 and 2 are not joined to the carapace by the hypodermal cells, and these two types are found in Palaeozoic ostracods. Eye type 3, 4, 5 and 6 are extended on eye stalks, tightly joined to the carapace by the hypodermal cells, and use the carapace as the refractive cuticle lens. Eye type 3 appeared in the Permian, and eye types 4, 5 and 6 appeared in the Early Jurassic. The design of the podocopid naupliar eye diversified in the Early Jurassic.     

A well‐preserved isopod from the Middle Jurassic of southern Germany and implications for the isopod fossil record

A new isopod species, Eonatatolana geisingensis gen. et sp. nov., is described from Middle Jurassic shallow‐water sediments of southern Germany. It shows not only the almost completely preserved dorsal morphology but, in addition, details of the cephalic appendages, the pereiopods, pleopods and uropods. The presence of ambulatory pereiopods I–VII of a wide tridentate mandibular incisor with prominently developed posteriormost tooth and a narrow frontal lamina indicates that the new species belongs to the subfamily Conilerinae of family Cirolanidae within the suborder Cymothoida. It is closer to the species of the modern genus NatatolanaBruce than to any fossil isopod hitherto described. The isopod fossil record as well as current practices of isopod taxonomy in palaeontology are discussed, and the facies distribution and fossilization of isopods is reviewed with examples from the Jurassic.     

Ten more years of discovery: revisiting the quality of the sauropodomorph dinosaur fossil record

Spatiotemporal changes in fossil specimen completeness can bias our understanding of a group's evolutionary history. The quality of the sauropodomorph fossil record was assessed a decade ago, but the number of valid species has since increased by 60%, and 17% of the taxa from that study have since undergone taxonomic revision. Here, we assess how 10 years of additional research has changed our outlook on the group's fossil record. We quantified the completeness of all 307 sauropodomorph species currently considered valid using the skeletal completeness metric, which calculates the proportion of a complete skeleton preserved for each taxon. Taxonomic and stratigraphic age revisions, rather than new species, are the drivers of the most significant differences between the current results and those of the previous assessment. No statistical differences appeared when we use our new dataset to generate temporal completeness curves based solely on taxa known in 2009 or 1999. We now observe a severe drop in mean completeness values across the Jurassic–Cretaceous boundary that never recovers to pre-Cretaceous levels. Explaining this pattern is difficult, as we find no convincing evidence that it is related to environmental preferences or body size changes. Instead, it might result from: (1) reduction of terrestrial fossil preservation space due to sea level rise; (2) ecological specificities and relatively high diagnosability of Cretaceous species; and/or (3) increased sampling of newly explored sites with many previously unknown taxa. Revisiting patterns in this manner allows us to test the longevity of conclusions made in previous quantitative studies.     

The encrustation of fossil and recent sea-urchin tests: ecological and taphonomic significance

A comparison of fossil ( Echitwlampas sp. from the Lower Miocene Zogelsdorf Formation, Austria) and Recent ( Schizaster canaliferus from the northern Adriatic Sea) irregular sea-urchin tests shows that, upon their death, burrowing echinoids can serve as a substrate for a dense epigrowth. Size, shape, stable orientation, and surface residence-time were identified as key factors governing encrustation. The encrusters on fossil Echinolampas were bryozoans, serpulid polychaetes, barnacles, and coralline algae, while the recent material was initially encrusted by serpulids and hydrozoan colonies, and ultimately covered by the full range of sessile, hemi-sessile, and vagile species characterizing the benthic community in the Adriatic. In Echinolampas , epigrowth was more abundant on the lower (oral) surface; this specific distribution was echoed in S. canaliferus , where epigrowth started on the bottom side and grew upward. This indicates that the tests have a stable orientation and a surface residence-time long enough to allow intense encrustation. A taphonomic model is developed, and the role of encrustation on such special substrates for overall community structure is discussed. The Recent/fossil comparison provides new insights for both fields of study: the recent material indicates the role of soft-bodied faunas as well as the complexity of small-scaled ecological processes; the fossil material reflects many of the above phenomena and adds important taphonomic details on the fate of encrusted biogenic structures and on encruster growth patterns and distributions.     

Decay of vertebrate characters in hagfish and lamprey (Cyclostomata) and the implications for the vertebrate fossil record

The timing and sequence of events underlying the origin and early evolution of vertebrates remains poorly understood. The palaeontological evidence should shed light on these issues, but difficulties in interpretation of the non-biomineralized fossil record make this problematic. Here we present an experimental analysis of decay of vertebrate characters based on the extant jawless vertebrates (Lampetra and Myxine). This provides a framework for the interpretation of the anatomy of soft-bodied fossil vertebrates and putative cyclostomes, and a context for reading the fossil record of non-biomineralized vertebrate characters. Decay results in transformation and non-random loss of characters. In both lamprey and hagfish, different types of cartilage decay at different rates, resulting in taphonomic bias towards loss of 'soft' cartilages containing vertebrate-specific Col2α1 extracellular matrix proteins; phylogenetically informative soft-tissue characters decay before more plesiomorphic characters. As such, synapomorphic decay bias, previously recognized in early chordates, is more pervasive, and needs to be taken into account when interpreting the anatomy of any non-biomineralized fossil vertebrate, such as Haikouichthys, Mayomyzon and Hardistiella.     

Preface: The phylogeny, fossil record and ecological diversity of ostracod crustaceans

After more than two centuries of research, more than 65,000 living and fossil ostracod species have been described and studied, yet much remains to be learned about this ancient, widespread and diverse group of bivalved arthropods. Their higher classification and phylogeny are subjects of vigorous debate, as is their position in the broader picture of crustacean phylogeny. At the same time, major advances in our understanding of ostracod lineages and their relationships are resulting from the application of innovative approaches and techniques. This preface provides a contextual overview of the 15 contributions to this volume, which resulted from the 14th International Symposium on Ostracoda (ISO2001) held in 2001at Shizuoka, Japan. As such it provides a cross-section of topics at the forefront of research on the evolution and diversity of Ostracoda, and indicates directions for future work.     

Phylogeny and adaptive diversity of rodents of the family Ctenomyidae (Caviomorpha): delimiting lineages and genera in the fossil record

Differentiation of genera of the modern (Late Miocene to Recent) South American rodent family Ctenomyidae would have been linked to the acquisition of disparate adaptations to digging and life underground. In accordance with this hypothesis, the delimitation of lineages and genera in the ctenomyid fossil record is evaluated here following an adaptation-rooted criterion that involves both an assessment of the monophyly and of the adaptive profiles of recognized clades. The application of such a criterion, including morphofunctional information, delimited four cohesive lineages among crown ctenomyids (i.e. euhypsodont species of the Late Miocene to Recent): Eucelophorus (Early Pliocene–Middle Pleistocene), Xenodontomys-Actenomys (Late Miocene–Pliocene), Praectenomys (Pliocene) and Ctenomys (including Paractenomys ; Pliocene–Recent); in addition, the results supported the status of Xenodontomys as a paraphyletic ancestor of Actenomys . The cladogenesis that gave rise to the crown group would have occurred immediately after the acquisition of euhypsodonty in a Xenodontomys simpsoni -like ancestor during the Late Miocene. This putative ancestor would have had fossorial habits and moderate digging specializations, an adaptive profile maintained in Xenodontomys-Actenomys . Eucelophorus and Ctenomys would have independently evolved subterranean habits at least since the Pliocene. Although the earliest history of the only living representative, Ctenomys , is known only fragmentarily, remains from Esquina Blanca (Uquía Formation), in north-western Argentina, suggest a minimum age of around 3.5 Ma (Early–Late Pliocene) for the differentiation of the genus. This date agrees with recent molecular estimates.     

Anoxia can increase the rate of decay for cnidarian tissue: Using Actinia equina to understand the early fossil record

An experimental decay methodology is developed for a cnidarian model organism to serve as a comparison to the many previous such studies on bilaterians. This allows an examination of inherent bias against the fossilisation of cnidarian tissue and their diagnostic characters, under what conditions these occur, and in what way. The decay sequence of Actinia equina was examined under a series of controlled conditions. These experiments show that cnidarian decay begins with an initial rupturing of the epidermis, followed by rapid loss of recognisable internal morphological characters. This suggests that bacteria work quicker on the epidermis than autolysis does on the internal anatomy. The data also show that diploblastic tissue is not universally decayed more slowly under anoxic or reducing conditions than under oxic conditions. Indeed, some cnidarian characters decay more rapidly under anoxic conditions than they do under oxic conditions. This suggests the decay pathways acting may be different to those affecting soft bilaterian tissue such as soft epidermis and internal organs. What is most important in the decay of soft polyp anatomy is the microbial community, which can be dominated by oxic or anoxic bacteria. Different Lagerstätte, even of the same type, will inevitably have subtle difference in their bacterial communities, which among other factors, could be a control on soft polyp preservation leading to either an absence of compelling soft anthozoans (Burgess Shale) or an astonishing abundance (Qingjiang biota).     

Consequences of elevated temperature and pCO2 on insect folivory at the ecosystem level: perspectives from the fossil record

Paleoecological studies document the net effects of atmospheric and climate change in a natural laboratory over timescales not accessible to laboratory or ecological studies. Insect feeding damage is visible on well‐preserved fossil leaves, and changes in leaf damage through time can be compared to environmental changes. We measured percent leaf area damaged on four fossil leaf assemblages from the Bighorn Basin, Wyoming, that range in age from 56.1 to 52.65 million years (Ma). We also include similar published data from three US sites 49.4 to ~45 Ma in our analyses. Regional climate was subtropical or warmer throughout this period, and the second oldest assemblage (56 Ma) was deposited during the Paleocene–Eocene Thermal Maximum (PETM), a geologically abrupt global warming event caused by massive release of carbon into the atmosphere. Total and leaf‐chewing damage are highest during the PETM, whether considering percent area damaged on the bulk flora, the average of individual host plants, or a single plant host that occurs at multiple sites. Another fossil assemblage in our study, the 52.65 Ma Fifteenmile Creek paleoflora, also lived during a period of globally high temperature and pCO₂, but does not have elevated herbivory. Comparison of these two sites, as well as regression analyses conducted on the entire dataset, demonstrates that, over long timescales, temperature and pCO₂ are uncorrelated with total insect consumption at the ecosystem level. Rather, the most important factor affecting herbivory is the relative abundance of plants with nitrogen‐fixing symbionts. Legumes dominate the PETM site; their prevalence would have decreased nitrogen limitation across the ecosystem, buffering generalist herbivore populations against decreased leaf nutritional quality that commonly occurs at high pCO₂. We hypothesize that nitrogen concentration regulates the opposing effects of elevated temperature and CO₂ on insect abundance and thereby total insect consumption, which has important implications for agricultural practices in today's world of steadily increasing pCO₂.     

毛果苔草湿地植物营养元素分布及其相关性

研究生物与环境中化学因子之间的相互作用过程 ,主要是指化学物质在生态系统中的运移、转化及归趋与效应。化学物质包括营养物质、污染物质和在生物与环境之间、生物与生物之间起媒介作用的次生代谢物质[1] 。对植物不同组织营养成分的季节性变化研究多集中于叶子 ,但对其他部分的研究则较少[10 ] ,分解过程并不是完全始于凋落物到达地面 ,在凋落前就受到渗滤、裂解和真菌的作用[12 ] ;对枯落物中的有机物质和营养物质浓度的了解可以预测枯落物的分解速率[11] 。目前 ,湿地的研究偏重于资源的开发与利用 ,而对湿地生态系统的生态过程的定位…     

湿地生态系统服务功能及其价值核算——以福州市为例

湿地在生态保护和社会发展中占据重要地位,科学合理评估湿地生态系统价值,是湿地保护与合理开发、确保湿地资源可持续性利用的基础。如何科学有效、标准化地评估湿地生态系统生产总值(GEP)并使之纳入国民经济体系核算是科学界和政府部门关注的焦点。本研究构建了湿地生态系统生产总值核算框架体系,并以福州市为研究案例,以多源数据为基础,从功能量与价值量层面,开展了福州市湿地GEP核算研究。结果表明: 2015年,福州市湿地生态系统GEP为2392.33亿元,主要源于湿地的生态调节服务价值(1578.69亿元,占总价值的66.0%),约是产品供给服务价值和精神文化服务价值的2.2和15.6倍。湿地生态调节服务中,以水流动调节服务价值和气候调节服务价值最高,两者占生态调节服务价值的82.9%。福州市湿地单位面积生态调节价值为134.78万元·hm^-2,高于全国水平。福州市各区县中,闽清县湿地生态系统价值量最大,为888.31亿元,占福州市湿地生态系统产品供给和生态调节总价值量的40.1%。福州市滨海湿地的生态调节服务价值最大,约分别是河流湿地和人工湿地类型的2.5倍。福州市湿地生态系统GEP核算是“绿水青山就是金山银山”理念城市尺度的重要践行,为指导地方政府科学管理湿地生态系统提供了技术支撑。     

A fossil heron from the early Oligocene of Belgium: the earliest temporally well‐constrained record of the Ardeidae

We describe the earliest temporally well‐constrained fossil that can be assigned to the Ardeidae (herons), from the lowermost Oligocene (32.0–33.0 million years ago) of Belgium. The specimen, a partial tarsometatarsus, belongs to a small species and is described as Proardea? deschutteri n. sp. It exhibits the characteristic tarsometatarsus morphology found in extant heron species, but a confident assignment to one of the ardeid subclades is not possible and even the assignment of the new fossil species to the crown group (the clade including the extant species) cannot be established. The fossil indicates a divergence of herons from their sister taxon by at least the earliest Oligocene, and current paleontological data suggest that herons arrived in Europe shortly after a major faunal turnover at the Eocene/Oligocene boundary. We consider that dispersal is the likely reason for the sudden appearance of herons in the earliest Oligocene of Europe but it is uncertain from where exactly this took place, with Asia and Africa being among the candidate areas.     

Oligocene–Neogene fossil history of Asian endemic conifer genera in Japan and Korea

Temporal and spatial changes of ten conifer genera that are endemic to East Asia were analyzed based on fossil data from humid temperate forests in the Japanese Islands and Korean Peninsula to elucidate the phytogeographic history, and to understand differences between those genera eliminated from the Japanese Islands and those that remained extant. All these genera, except for Thujopsis, have existed in the area since the Paleogene and remained in the Japanese islands after initial separation from the continent at the early–middle Miocene. Fossil representatives of locally extinct six genera have tendencies to adapt to wider ranges of climatic conditions than their modern relatives. Metasequoia, Glyptostrobus, and Taiwania began to change their distributions since the late Miocene possibly through habitat partitioning. Keteleeria, Pseudolarix, and Cunninghamia appeared to have expanded their habitat toward warmer conditions during the mid‐Miocene Climatic Optimum and then became restricted to warmer forest vegetation by the end of Pliocene. Overall changes in their distribution can be explained by climatic effects. On the contrary, three genera endemic to Japan (Sciadopitys, Cryptomeria, and Thujopsis) followed clearly different trends from the others. Cryptomeria and Thujopsis were especially adapted to cooler‐temperate climate and they retained their habitat areas in the northern part of Japan. During the late Miocene–Pliocene, the islands connected with the Eurasian continent again, which probably acted as a corridor for warm‐adapted genera to disperse southwest. Current data suggest that ecological requirements of each genus might be essential to determine whether they could survive on the Japanese Islands.