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The Aleksandrovskoe locality (Krasnoufimsk district of the Sverdlovsk Region, Fore-Urals; Lower Permian, Kungurian Stage, Koshelevsk Formation), its taphonomy and taxonomic composition of the fossil flora are discussed. A new lycopsid, Ufadendron ufaensis gen. et sp. nov., with well-developed infrafoliar aerenchyma is described. The new plant is morphologically similar to the group of Early Carboniferous Central Angaran lycopsids (Tomiodendron Radczenko emend. S. Meyen, Lophiodendron Zalessky emend. S. Meyen, Angarophloios S. Meyen). Survival of a relic lycopsid of Central Angaran type with infrafoliar aerenchyma at the periphery of Angaraland up to the mid-Permian is discussed in terms of the “Lazarus taxa” phenomenon.

During the Eocene, iguanid lizards were a diverse and widespread group in Europe. Prior to this study, no iguanid was known in Europe after the Eocene-Oligocene boundary. Some specimens from the locality of Pech-du-Fraysse (late Oligocene, MP28, France, Phosphorites du Quercy) are described. They belong to the Iguanidae, more precisely to the genus Geiseltaliellus, demonstrating that iguanid lizards survived the Eocene-Oligocene extinctions in Europe, only to disappear in the aftermath, certainly during the latest Oligocene. Thus, Geiseltaliellus is recognized as a Lazarus taxa. Explanations pertaining to the Lazarus effect are examined.

The continuous and richly fossiliferous Ordovician succession of China (particularly South China) comprises a heterogeneous suite of litho- and bio-facies, which has been a main focus of stratigraphical and palaeontological research in recent years. Among the seven GSSPs established in China, three are within the Ordovician System, and the GSSP of the Darriwilian Stage at Huangnitang, Changshan County, western Zhejiang Province, was the first “golden spike” in China and the first for the Ordovician System. A series of case studies have revealed that: (1) the Ordovician radiation of some fossil groups on the Upper Yangtze Platform (e.g., brachiopods and graptolites) reached their first α-diversity acme in the Didymograptellus eobifidus Biozone, four zones earlier than the global trend; (2) the β-diversity peak was attained 3–4 zones later than the α-diversity peak; (3) many brachiopod communities or faunas first occurred in the central part of the Upper Yangtze Platform and subsequently expanded to both more offshore and near-shore facies; (4) diachroneity existed in many aspects of the radiation. The end-Ordovician mass extinction was a severe event in South China. Two pulses of the extinction are recognized for a number of major fossil groups, some being most strongly affected during the first pulse whereas the others suffered during the second pulse. Macroevolution during the Ordovician–Silurian transition has been investigated in detail, and the role of the Lazarus effect has been found to be less important than previously believed.

Feral ungulates, such as pigs, are highly destructive to island ecosystems and are therefore often the target of eradication efforts. To succeed in eradication, however, managers must address a question made formidable by the great difficulty of detecting animals at very low levels of abundance: how will we know when elimination has been achieved? We developed and tested a framework to address this problem in a program to remove feral pigs from Santa Cruz Island, California. In an unprecedented timeframe for an island of this size, the program has progressed to a point at which pigs can no longer be detected. We describe seven key attributes of our approach, and how they have increased the likelihood that our inability to detect additional pigs indicates successful eradication, rather than the pigs having become better at escaping detection. This approach represents an important advance in the practice of eradication that can serve as a model for increasing the pace and scale of island restoration around ...

Global analyses of 88 families and 284 genera of brachiopods from middle Ashgill, Late Ordovician, to early–middle Rhuddanian, Early Silurian, indicate that 18.6% and 12.5% of families and 51.0% and 41.3% of genera were eliminated in the first and second phases of the end-Ordovician mass extinction, respectively, with the total loss of 28.4% of families and 69.0% of genera in the crisis. New investigation demonstrates that brachiopods, at both generic and familial levels, suffered greater during the first phase than during the second phase. Four groups (victims, relicts, survivors, and new arrivals) are distinguished by their stratigraphical ranges. Generic survivors, occurring in the Kosov Province during the Hirnantian, can be split into three types with respect to their changing abundance: increasing, declining, and Lazarus taxa. Among the 88 genera that survived, numerous declining genera occurred in the Hirnantian: 16 Lazarus families and 18 Lazarus genera are provisionally known and may be regarded as end members of the declining type. Comparison of the abundance, population size, and distribution patterns of declining and Lazarus taxa shows important similarities between these two types which contribute to a better understanding of the nature of Lazarus taxa. In addition to these biological attributes, taphonomic failure and generally poor preservation, together with collecting bias and inadequate systematic data, are clearly involved. More collections will undoubtedly globally reduce the number of Lazarus taxa. A single, common refugium for end-Ordovician brachiopods probably did not exist; rather, these taxa used paleogeographically scattered locations in a range of environments for survival.

A new technique for the investigation of deep levels on irradiated silicon by measuring the charge collection efficiency (CCE) of samples from 220 K down to 90 K is presented here. The temperature and time dependencies of the CCE have been measured with unprecedented precision and resolution for standard and oxygenated silicon diodes, and the data obtained have been analyzed in the framework of the Lazarus effect and polarization models, extracting information about the radiation-induced deep levels in the materials. Results are presented and discussed in terms of these models and what can be inferred from them when applied to experimental data.

Lists of extinct Australian plants created over the last 20 years were examined and were shown to have high levels of turnover. In general, the lists are contracting in length and their composition changes substantially, a phenomenon we term the ‘Lazarus effect’. There is little explanation for these changes in the cryptic nature of species habits, or their distribution in remote locations. Most of the turnover is due to changes in knowledge about the species' status, and changes in taxonomy. Lists maintained in some other countries are more stable, but at the potential cost of underestimating the extent of extinction. Comparisons between jurisdictions and between lists are difficult because of different attitudes taken towards uncertainty and variation in research effort among different taxa. For any assessment that uses lists of extinct or threatened species as indicators of environmental change, we recommend that sources of bias are reduced and that uncertainties in lists are made more transparent. An important step in this process is to distinguish listing changes due to a change in status from those due to a change in knowledge about distribution, abundance and taxonomy. Assessments of environmental change based on species lists should be standardised to exclude these latter sources of variation, and take into account new assessments of previously unevaluated taxa.

Originally, Charliea Mamay was considered to be a pinnately compound leaf having linear–oblong ultimate segments with apices divided into two to four, nearly equal truncated lobes when it was described from the Upper Pennsylvanian of New Mexico. However, evaluation of the type material and newly collected specimens of the generitype as well as other fossils representing two new species demonstrates that the ultimate segments are alternately arranged in two rows (two-ranked) on a narrow stem and that the fossil is not a pinnately compound leaf, but a leafy plagiotropic shoot. Moreover, the apical lobes of the ultimate segments are rounded to pointed and not truncated as first thought. The new species, C. guntheri and C. readii, are distinguished from the generitype, C. manzanitana Mamay, in the shape and size of the ultimate segments (here termed leaves), and the smaller number of veins entering the apical lobes. Charliea guntheri and C. readii occur in the Lower Pennsylvanian of Utah and the Upper Pennsylvanian of New Mexico, respectively, and extend the stratigraphic range of the genus significantly. As a consequence, Charliea seems to exhibit what may be referred to as a modified ‘Lazarus effect’ since the species assigned to it occur at the base and top of the Pennsylvanian but not in the intervening interval.

The main factor, which leads to semiconductor detector degradation in high-energy physics experiments, is the introduction of lattice defects in the detector material produced by radiation. Based on the spectrum of radiation induced defects in the silicon bulk, the overview of effects and mechanisms responsible for the changes in the main detector parameters such as effective concentration of the space charge in the depleted region, space charge sign inversion, charge collection efficiency, and detector breakdown voltage are considered. Special attention is paid to the electric field distortion related with high concentration of radiation induced deep traps, which is the key question for the design of detectors operating at cryogenic temperature. In particular, the charge collection recovery at low temperature, often refereed as the Lazarus effect, and the limitation for the detection rate related to the polarization effect are considered.

It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, "resuscitate" when operated at temperatures below 130 K. This is often referred to as the "Lazarus effect". The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors.

The many definitions and interpretations associated with the ‘Lazarus effect’ have considerably confused this notion. While several authors regard the Lazarus effect as the temporary disappearance of taxa from the fossil record in any given time interval, many others consider the Lazarus effect as a pattern restricted to mass extinction episodes. The adequacy of the fossil record is the key for interpreting the Lazarus pattern: either Lazarus taxa reflect the incompleteness of the fossil record (the ‘stratigraphic alternative’), or they illustrate genuine extinction-linked phenomena (the ‘biological alternative’). The latter option includes two traditional hypotheses implying existence of refugia and post-extinction low population diversity. Differences between these two biological explanations seem to be more rhetorical than substantiated. In addition, the sampling intensity is an external factor commonly linked with both the stratigraphic and the biological alternatives. Interpreting the Lazarus effect is an asymmetrical procedure because the biological alternative is only favoured when the stratigraphic one cannot be documented. Consequently, analytical techniques assessing the completeness of the fossil record are critical to understand the meaning of Lazarus taxa. In particular, gap distributions are better compared with extinction and origination rates rather than with total diversity estimates. Finally, the Lazarus effect should be defined broadly to include range gaps from any given time interval. Copyright © 2001 John Wiley & Sons, Ltd.

An increasing interest in the behaviour of silicon detectors at cryogenic temperatures has been awakened by the discovery of the so-called Lazarus effect, namely the recovery of charge collection efficiency (CCE) by means of cryogenic cooling. We measured the CCEs of three single diodes previously irradiated with different neutron fluences. The current-voltage characteristic were measured at 300 and 77 K, showing that the low-temperature operation considerably decreases the steady-state current. This is also the case when a forward voltage bias is applied, which then becomes a suitable option. At 77 K, in the case of samples irradiated with 5 x 10 14 neutrons cm -2 , the CCE is completely recovered. A third sample irradiated with 2 x 10 15 neutrons cm -2 shows a 60% CCE at 250V forward bias.

Without studying the causes of the F/F boundary mass extinction, the precise analysis of ostracod species shows evolutionary process only discernable at the global scale. About 75% of all neritic species disappeared in the Uppermost Frasnian in all studied regions of the world. Others survived, with some geographic changes, owing to littoral refuges (Lazarus eflect). Deep benthic ostracods seem almost untouched by this event. We show that new post-event species resulted from allopatric speciations by migration between neritic provinces or along continental slopes towards deeper environments. During the event surviving lineages show a continuous gradation from unscathed species to chronocline species, to phyletic subspeciations or speciations (= pseudo extinctions) and even to new genera. The durability of lineages is controlled by the migration of populations.

Four major biotic crises are recognized in the history of the Upper Silurian graptoloids. While the causes of extinction are largely unknown, the scenarios of the crises are fairly well ascertained. A model of recovery proposed here implies two alternatives: (1) some of the relic species exhibit great abundance frequently associated with a subnormal phenotype (the post‐event syndrome) and the ensuing rediversification involves indigenous speciation or (2) as a result of the lack of evolutionary response on the part of the local survivors, vacant habitats are filled by immigrants. Numerous cryptic and Lazarus taxa among the immigrants indicate the presence of pelagic refuges and centers of evolution. They may be identified as Central Water masses bounded by gyres.

The biotic crisis of the Middle Permian through Early Triassic is unmatched in the Phanerozoic in terms of taxonomic diversity losses and paleoecological reorganization. However, the potential taphonomic bias from post-mortem diagenesis for this crucial time has not been evaluated. We assessed the quality of the fossil record during this interval by quantifying the number of Lazarus taxa using our own database, data available in the Paleobiology Database and previous compilations. We also quantitatively tested for paleoecological differences between silicified versus non-silicified faunas. Herein we report that there is no major taphonomic bias due to skeletal mineralogy or fossil preservation affecting the Middle and Late Permian fossil record, but that aragonite-shelled molluscs may exhibit a significant Lazarus effect during the Induan. We propose that a variety of mechanisms affected the fossil record of the Paleozoic/Mesozoic transition, including ocean chemistry, paleobiology of the examined groups, and human influences on taxonomic and sampling practices.

Lazarussuchus inexpectatus, nov. gen., nov. sp. from the Oligocene, is a new form of Choristodera which extends the longevity of this clade into the Middle Tertiary. It bears a remarkable assemblage of primitive characters. In this respect it is similar to the middle and late Jurassic form, Cteniogenys, than to the more derived highly aquatic forms of the Cretaceous and Paleocene. Some morphological features indicate it is more terrestrial than any other genus in the Choristodera.

The discovery of the so-called Lazarus e!ect, namely the recovery of the charge collection e$ciency (CCE) of irradiated silicon detectors by means of cryogenic cooling has entailed an increasing interest in the behavior of silicon detectors at cryogenic temperatures. We have measured the CCE of a silicon p}i}n diode detector previously irradiated with an equivalent #uence of 1]1015 n/cm2 neutrons of 1 MeV energy. The charge collection e$ciency has been measured at 77 K, showing that the low-temperature operation considerably decreases the bias current. This is also the case when forward voltage bias is applied, which then becomes a suitable option. In this condition, the sample shows a charge collection e$ciency in excess of 65% at 250 V corresponding to a most probable signal for a minimum ionizing particle of 21 000e~. ( 2000 Elsevier Science B.V. All rights reserved.

Over 75% of the seedlings of the endemic sandplain grassland perennial, northern blazing star (Liatris scariosa var novae-angliae), die within their first growing season. During a study of the reproductive ecology of this rare plant, we found 17 seedlings whose leaves had become completely desiccated and brown and were classified as dead. Upon subsequent inspection, we discovered that these seedlings had developed a new shoot with green leaves. We have called this rejuvenation “the Lazarus effect.” These seedlings became dormant by late June, which coincided with extended periods of drought, and were senescent for periods of 4–10+ wk. Rejuvenation of leaf-senescent seedlings occurred in late July and August, coincident with periods of increased precipitation. Survivorship of “Lazarus” seedlings to their second summer (9 of 17, 53%) was similar to survivorship of “normal” seedlings (≈58%) which did not senesce. Thus, becoming senescent did not have undue costs to survivorship.

A new Silicon microstrip detector was developed for the COMPASS experiment at the CERN / SPS. The detector was installed and successfully commissioned in the year 2002. It provides a space resolution of down to 10 µm and a time resolution of the order of 3 ns. In order to increase its radiation tolerance, it was designed to be operated at a temperature of 130 K. In the second part a first measurement of the transverse polarization of Lambda hyperons from quasi-real photo-production in the COMPASS experiment was performed. Averaged over the full kinematics a positive polarization of 4.4 +/- 0.8 (stat.) +/- 0.5 (sys.) % was found. In the target fragmentation region the behaviour of the polarization of photo-produced Lambdas was found to be similar to the case of meson-production. Für das COMPASS Experiment am CERN/SPS wurde ein neuer Silizium Mikrostreifenzählers entwickelt. Die Detektoren wurden im Jahr 2002 installiert und erfolgreich in Betrieb genommen. Die Ortsauflösung beträgt ca. 10 µm und die Zeitauflösung ca. 3 ns. Um die Strahlungshärte zu erhöhen, ist der Detektor für eine Betrieb bei einer Temperatur von 130 K ausgelegt. Im zweiten Teil der Arbeit wird eine erste Messung der transversalen Polarisation von Lambda-Hyperonen aus quasi-reeller Photoproduktion vorgestellt. Über die gesamte Kinematik gemittelt ergibt sich eine Polarisation von +4.4 +/- 0.8 (stat.) +/- 0.5 (sys.)%. Die transversale Polarisation aus photoproduzierten Lambdas zeigt in der Targetfragmentation ein ähnliches Verhalten wie die Polarisation von Lambdas aus Mesonproduktion.

The living Laotian rodent Laonastes aenigmamus , first described in early 2005, has been interpreted as the sole member of the new family Laonastidae on the basis of its distinctive morphology and apparent phylogenetic isolation from other living rodents. Here we show that Laonastes is actually a surviving member of the otherwise extinct rodent family Diatomyidae, known from early Oligocene to late Miocene sites in Pakistan, India, Thailand, China, and Japan. Laonastes is a particularly striking example of the “Lazarus effect” in Recent mammals, whereby a taxon that was formerly thought to be extinct is rediscovered in the extant biota, in this case after a temporal gap of roughly 11 million years.

R. J. Twitchett writes: Palaeontologists grudgingly accept that the fossil record of most taxa is very patchy and incomplete. A particular taxon will appear in the fossil record, and then disappear for any number of millions of years, only to reappear again, apparently unchanged, in younger strata. This disappearance and reappearance is termed the Lazarus effect. Thus, in any particular interval of time a Lazarus taxon is one that is not present in the fossil record, but which we know must have existed by virtue of the presence of older and younger specimens. ⇓Wignall & Benton (1999) are concerned with the importance of the Lazarus effect during extinction‐recovery intervals. Traditional explanations for this phenomenon are: (i) a reduction in the quality of the fossil record, and/or (ii) a migration of taxa into (as yet) undiscovered refugia. Wignall & Benton make the novel suggestion that the Lazarus effect is, instead, due to periods of low abundance. Implicit in this argument is the hypothesis that population size has to exceed a critical threshold before a taxon stands any chance of becoming fossilized. Below this threshold the population remains viable, but we simply have no record of its existence. They make the reasonable assumptions that this threshold will vary between environments (presumably also between taxa), and is essentially ‘impossible to quantify’. While I agree that this is a credible explanation for the Lazarus effect, I do not consider that the tests constructed by Wignall & Benton are sufficiently rigorous to disprove the traditional alternatives. #### Testing the ‘quality’ of the fossil record For the Permian–Triassic event the authors use the number of fossiliferous, shallow‐marine formations from each stage as a measure of the quality of the fossil record. As there is no change in the number of formations from the Changxingian to the Griesbachian, they infer that the quality of …

The widespread occurrence of stratigraphic sequences suggests that a large fraction of the stratigraphic record is systematically biased. For example, sequences in landward areas tend to have more symmetrical transgressive-regressive records as well as hiatuses of long duration. Sequences in shelf settings have highly asymmetrical regressive-dominated records, with relatively minor hiatuses and condensed sections. Deeper settings tend to have more symmetrical transgressive-regressive records, with significant condensed sections. This stratigraphic bias can both mask true paleontological patterns and create apparent patterns.Sequence architecture implies that environments are continually changing, whether this change is obvious in lithofacies or not. Given that facies control has been documented in many benthic taxa as well as in planktic/nektic/nektobenthic groups that are biostratigraphically important (e.g., conodonts, ammonoids, and graptolites) continuous change in lithofacies suggests that faunas should continually change upsection–and that this change should reflect changing environments, not in situ evolution. Vertical changes in taxonomic composition and morphology are more easily explained as clines or ecophenotypic gradients, rather than as evolutionary sequences. Because stratigraphic sequences cause vertical facies successions to be repeated, fossil morphologies should repeatedly appear within a section, with their occurrences separated by a hierarchy of gaps, varying in scale from short-term taphonomic-bias gaps through parasequence-scale gaps to sequence-scale gaps. Morphotypes with stratigraphically discontinuous ranges commonly have been named separately despite the morphological similarity at different horizons, and in some cases, this pattern has been interpreted as iterative evolution. However, sequence architecture and facies control could easily produce this pattern. It is argued here that the Lazarus Effect of Jablonski is far more pervasive than previously acknowledged and can occur at a range of scales from a variety of processes.The juxtaposition of dissimilar facies at sequence boundaries can produce apparent paleontological events, while facies control will mask true paleontological events. Apparent first occurrences will be concentrated immediately above sharp facies contacts at sequence boundaries, whereas apparent last occurrences will be concentrated immediately below sequence boundaries. However, a true first occurrence within a section will inevitably be delayed from the true first occurrence within the basin because of facies control; likewise, true last occurrences within a section will precede the true last occurrence within a basin. The magnitude of this delay/precedence will vary with the position of the section within the basin. The asymmetric sequences of midshelf settings can cause a delay of up to one full sequence; more symmetrical sequences of landward and basinward settings can create a of up to approximately one-half of a sequence.What can be done about this source of bias? One solution is to create a tight eventstratigraphic correlation network in conjunction with a basin-wide array of sections to be able to track any given facies through time and space. A second solution, useful where such correlations are not possible or such an array of sections is not available, would be to compare within-habitat faunal and morphologic change between sequences.Possibly the most intriguing possibility is that the same processes that create stratigraphic sequences also drive macroevolutionary change through geologically rapid reassortment of sedimentary environments and the redistribution of barriers to isolation.

The record of latest Cretaceous and earliest Tertiary macroinvertebrates in the K-T boundary sequence at Braggs, Alabama is documented by high resolution stratigraphic data. Latest Maastrichtian and earliest Danian strata lie within a reversed magnetic interval identified as Chron C29R. The faunal decline across this interval is abrupt and severe, with 50% of the terminal Cretaceous species dropping out of the record. A pronounced Lazarus Effect is displayed across the boundary. However, persistently high Cretaceous and low Tertiary diversity, coupled with good stratigraphic resolution and comparable quality of preservation of both Cretaceous and Tertiary faunas in similar lithologies, all argue for a relatively abrupt decline. The Lazarus Effect is most likely the result of local extinction and/or migration rather than taphonomic or collection difficulties. If only previously published species lists were used in this study, either a gradual extinction pattern or a larger scale Lazarus Effect could have been invoked to explain the observed diversity changes. Extensive collecting, however, has revealed a persistently high diversity throughout the latest Maastrichtian. No stepwise extinctions were observed and most taxa represent widespread and long-ranging clades. The Braggs faunal transition is consistent with proposed catastophic extinction hypotheses, but a limit in temporal resolution of up to 0.8 Ma for the faunal turnover at this site allows ample time for other, longer-term extinction processes and patterns to have developed. This resolution is perhaps as good as can be expected with current methods and the shallow-marine character of the sequence.