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.     

Highly resolved early Eocene food webs show development of modern trophic structure after the end-Cretaceous extinction

Generalities of food web structure have been identified for extant ecosystems. However, the trophic organization of ancient ecosystems is unresolved, as prior studies of fossil webs have been limited by low-resolution, high-uncertainty data. We compiled highly resolved, well-documented feeding interaction data for 700 taxa from the 48 million-year-old latest early Eocene Messel Shale, which contains a species assemblage that developed after an interval of protracted environmental and biotal change during and following the end-Cretaceous extinction. We compared the network structure of Messel lake and forest food webs to extant webs using analyses that account for scale dependence of structure with diversity and complexity. The Messel lake web, with 94 taxa, displays unambiguous similarities in structure to extant webs. While the Messel forest web, with 630 taxa, displays differences compared to extant webs, they appear to result from high diversity and resolution of insect–plant interactions, rather than substantive differences in structure. The evidence presented here suggests that modern trophic organization developed along with the modern Messel biota during an 18 Myr interval of dramatic post-extinction change. Our study also has methodological implications, as the Messel forest web analysis highlights limitations of current food web data and models.     

Fossil water striders from the Middle Eocene fossil sites of Eckfeld and Messel,Germany (Hemiptera,Gerromorpha)

Water striders (Hemiptera, Gerromorpha) are a very distinct ecological group specially adapted for life on the water surface. The present paper reports on four species of Gerromorpha from the Middle Eocene fossil sites of Eckfeld and Messel describingLutetiabates eckfeldensis n. gen. et n. sp.,Cylindrobates messelensis n. gen. et n. sp. (both Gerridae), and two nymphs most probably of the genusGerris. The record of two new members of Gerridae from the Paleogene as well as the hitherto known Gerromorpha from fossiliferous resins document a distinctly higher diversity of water striders within die European Paleogene than today. Lastly, comments are made on the fossil history as well as on the palaeobiological and palaeobiogeographical significance of the faunas.     

Fossil water‐penny beetles (Coleoptera: Psephenidae: Eubrianacinae) from the Eocene of Europe,with remarks on their phylogenetic position and biogeography

Abstract: A species of water‐penny beetles is recorded from larval instars from the Middle Eocene Messel pit fossil site in Germany. This species clearly belongs to the psephenid subfamily Eubrianacinae, but its precise systematic affinities remain unclear. It is the second fossil species of this taxon recorded from Europe. The holotype of the first fossil species, Eubrianax vandeli Bertrand and Laurentiaux, 1963, is lost. The high number of fossil specimens from Messel allowed discussion of stratigraphic and spatial occurrence of the eubrianacine species in the Messel pit, but its larval ontogeny could not be unravelled. Because of the high number of fossils and their wide occurrence, it is inferred that the species from Messel gen. sp. 1 was an autochthonous faunal element of the Eocene Lake Messel, which might indicate that some parts of the former Lake Messel had a shore area with stones. The analysis of the phylogenetic position of both Eocene eubrianacine species showed that their phylogenetic placement cannot be resolved because preservational influences limit the evaluation of characters. The historical biogeography of Psephenidae and Eubrianacinae is analysed and discussed. The fossil record shows that psephenid beetles have fossil members occurring outside their current distribution range, so interpretations of their biogeography based only on extant members can be misleading.     

Zum Fortpflanzungsmodus fossiler Kleinlibellen (Insecta,Odonata, Zygoptera)

Fossil egg-sets of damselflies (Insecta, Odonata, Zygoptera) are recognized from well known localities such as Randecker Maar, Messel (both in Germany) and in an old record about sediments from the Upper Cretaceous of Bohemia (Czech Republic). Such finds bearing witness to the behaviour of certain fossil insects are extremely rare, especially in stratified sediments. Hitherto they have only been recorded from the Upper Oligocene Fossillagerstätte Rott near Bonn (Germany). Two different types of egg-sets could be distinguished; they were described and figured byHellmund &Hellmund (1991, 1993). It is striking that the gap between finds from the Upper Oligocène and those from modern times is mainly due to insufficient observations. The explained strategy of reproduction obviously evolved at least 95 m.a. ago and has been practiced unchanged today.     

Ein Archaeotrogon (Aves: Archaeotrogonidae) aus dem Mittel-Eoz?n der Grube Messel (Hessen, Deutschland)?

Zusammenfassung Ein Vogel aus dem Mittel-Eozän der Grube Messel (Hessen, Deutschland) wird als neue Gattung und Art der Archaeotrogonidae Mourer-Chauviré 1980 beschrieben (incertae sedis). Die Exemplare aus Messel wären die ersten artikulierten Skelette dieser Familie.Hassiavis laticauda n. gen. n. sp. unterscheidet sich vor allem im Bau des Coracoids von der GattungArchaeotrogon Milne-Edwards 1892. Besonders bemerkenswert ist die ausgezeichnete Erhaltung der Flügel- und Schwanzbefiederung einiger Exemplare. Einige Schwanzfedern des Holotypus zeigen eine Querbänderung, welche möglicherweise auf die ursprüngliche Pigmentierung dieser Federn zurückzuführen ist. Die phylogenetische Stellung der Archaeotrogonidae wird diskutiert. Zur Zeit sind keine Synapomorphien bekannt, welche diese Familie mit einer der bestehenden Ordnungen verbinden.

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An Archaeotrogon (Aves: Archaeotrogonidae) from the Middle Eocene of the Grube Messel (Hessen, Germany)?

Summary A bird from the Middle Eocene of the Grube Messel (Hessen, Deutschland) is described as a new genus and species of the Archaeotrogonidae Mourer-Chauviré 1980 (incertae sedis). The specimens from Messel would be the first articulated skeletons of this family.Hassiavis laticauda n. gen. n. sp. is distinguished from the genusArchaeotrogon Milne-Edwards 1892 in the morphology of the coracoid. The excellent preservation of the wing feathers and those of the tail in several of the specimens is exceptional. Some tail feathers of the holotype are barred, which might be traced back to the original pigmentation of these feathers. The phylogenetic position of the Archaeotrogonidae is discussed. At present no synapomorphies are known, which could set up a closer relationship between this family and one of the existing orders.

     

Short communication. Biomass and production of cyanobacteria in a coastal water of Sagami Bay, Japan

Cyanobacteria were relatively small contributors to carbon biomass (097-18%) in the euphotic zone. However, a higher contribution to production obtained at the surface water (16-45%) implies that they contribute more to carbon cycling than is expected from their biomass      

Phytoplankton structure and diversity in the eutrophic-hypereutrophic reservoir Paso de las Piedras, Argentina

This study aimed at analyzing the phytoplankton structure and dynamics in Paso de las Piedras Reservoir, Argentina, through the study of dominant species, diversity and similarity in relation with the abiotic environment. Samples were collected weekly or biweekly (January 2004–June 2005) at four sampling stations. The reservoir experienced a seasonal progression in phytoplankton composition that underlines six successional periods, each one characterized by the dominance of one or a few species. Cyanobacteria, green algae and diatoms were the most important constituents of the reservoir’s phytoplankton. Cyanobacteria dominated during summer and early autumn, green algae during late autumn and early winter, and diatoms during winter and spring. A high abundance of R. lacustris (Cryptophyceae) was observed during late September and early October. The general pattern of species succession is coherent with the general model of plankton seasonal succession described by the PEG model; however, the major discrepancy is the extremely short clear water phase observed. Successional periods were associated with changes in abiotic variables, and they showed differences in ecological traits. Cyanobacteria-Dictyosphaerium, Cyclotella, Stephanodiscus and Anabaena-diatom periods were characterized by a low number of cells, high diversity, with both dominance and specific richness low. On the contrary, during Cyanobacteria and Cyanobacteria II periods, the highest abundance was observed associated with low diversity and high dominance.     

The Influence of Indigenous Food Procurement Techniques on Populations of Cyanobacteria in pre-European Australia: A Potential Small-scale Water Amelioration Tool

During times of pre-European Australia, indigenous people utilized methods of food procurement that resulted in toxic phytochemicals from plants entering their waterholes. This paper focuses on three of these plants, namely the leaves of Acacia colei and Duboisia hopwoodii, which were used by hunters to poison water holes to stun fish or a drinking animal, and the seeds of Castanospermum australe, which were eaten following the leaching of toxins into a running stream. If consumed by humans, the main toxins from these plants—saponins/sesquiterpenes, nicotine/nornicotine, and australine/castanospermine—are fatal. However, it is undetermined whether populations of Cyanobacteria also can be affected. During this study, the previously mentioned plants were administered to populations of the species Anabaena circinalis, Microcystis aeruginosa, and Nodularia spumigena, while mimicking the traditional applications of these plants as closely as possible. Results varied with treatments and species; however, cell chlorosis manifested in nearly all treatments, concomitantly with thylakoid membrane disorganization. Cell dormancy typically manifested, along with destruction of populations at higher treatments. The results indicated that populations of Cyanobacteria could have been destroyed or inhibited by indigenous people during traditional applications of these plants. Findings presented herein indicate a more sophisticated and complex traditional Australian resource management scheme than is currently understood, contributing to the growing awareness of the plight of earlier indigenous Australians. The reintroduction of traditional water management techniques may have potential as a suitable small-scale water resource management strategy.     

Microbial communities and organic biomarkers in a Proterozoic‐analog sinkhole

Little Salt Spring (Sarasota County, FL, USA) is a sinkhole with groundwater vents at ~77 m depth. The entire water column experiences sulfidic (~50 μM) conditions seasonally, resulting in a system poised between oxic and sulfidic conditions. Red pinnacle mats occupy the sediment–water interface in the sunlit upper basin of the sinkhole, and yielded 16S rRNA gene clones affiliated with Cyanobacteria, Chlorobi, and sulfate‐reducing clades of Deltaproteobacteria. Nine bacteriochlorophyll e homologues and isorenieratene indicate contributions from Chlorobi, and abundant chlorophyll a and pheophytin a are consistent with the presence of Cyanobacteria. The red pinnacle mat contains hopanoids, including 2‐methyl structures that have been interpreted as biomarkers for Cyanobacteria. A single sequence of hpnP, the gene required for methylation of hopanoids at the C‐2 position, was recovered in both DNA and cDNA libraries from the red pinnacle mat. The hpnP sequence was most closely related to cyanobacterial hpnP sequences, implying that Cyanobacteria are a source of 2‐methyl hopanoids present in the mat. The mats are capable of light‐dependent primary productivity as evidenced by ¹³C‐bicarbonate photoassimilation. We also observed ¹³C‐bicarbonate photoassimilation in the presence of DCMU, an inhibitor of electron transfer to Photosystem II. Our results indicate that the mats carry out light‐driven primary production in the absence of oxygen production—a mechanism that may have delayed the oxygenation of the Earth's oceans and atmosphere during the Proterozoic Eon. Furthermore, our observations of the production of 2‐methyl hopanoids by Cyanobacteria under conditions of low oxygen and low light are consistent with the recovery of these structures from ancient black shales as well as their paucity in modern marine environments.     

Molecular signatures for the main phyla of photosynthetic bacteria and their subgroups

The bacterial groups corresponding to different photosynthetic prokaryotes are presently identified mainly on the basis of their branching in phylogenetic trees. The availability of genome sequences is enabling identification of many molecular signatures that are specific for different groups of photosynthetic bacteria. Our recent work has identified large numbers of signatures consisting of conserved inserts or deletions (indels) in widely distributed proteins, as well as whole proteins that are specific for various sequenced species/strains from Cyanobacteria, Chlorobi, and Proteobacteria phyla. Based upon these signatures, it is now possible to identify/distinguish bacteria from these phyla of photosynthetic bacteria as well as their major subclades in clear molecular terms. The use of these signatures in conjunction with phylogenomic analyses, summarized here, is leading to a holistic picture concerning the branching order and evolutionary relationships among the above groups of photosynthetic bacteria. Although detailed studies in this regard have not yet been carried on Chloroflexi and Heliobacteriaceae, we have identified some conserved indels that are specific for these groups. Some of the conserved indels for the photosynthetic bacteria are present in photosynthesis-related proteins. These include a 4 aa insert in the pyruvate flavodoxin/ferridoxin oxidoreductase that is specific for the genus Chloroflexus, a 2 aa insert in magnesium chelatase that is uniquely shared by all Cyanobacteria except the deepest branching Clade A (Gloebacterales), a 6 aa insert in an A-type flavoprotein that is specific for various marine unicellular Cyanobacteria, a 2 aa insert in heme oxygenase that is specific for various Prochlorococcus strains/isolates, and 1 aa deletion in the protein protochlorophyllide oxidoreductase that is commonly shared by various Prochlorococcus strains except the deepest branching isolates MIT 9303 and MIT 9313. The identified CSIs are located in the structures of these proteins in surface loops indicating that they may be important in mediating protein–protein interactions. The cellular functions of these conserved indels, or most of the signature proteins are presently unknown, but they provide valuable means for discovering novel properties that are unique to different groups of photosynthetic bacteria.     

Elucidating the affinities and habitat of ancient, widespread Cyperaceae: Volkeria messelensis gen. et sp. nov., a fossil mapanioid sedge from the Eocene of Europe

The sedges (family Cyperaceae) are an economically and ecologically important monocot group dating back at least to the Paleocene. While modern genera are mostly unknown before the Oligocene, several extinct taxa are recognized as the earliest sedges. Their affinities have been unclear until now, because they are found as isolated, often abraded fruits or endocarps. Exceptionally preserved sedge fossils from the Middle Eocene of Messel, Germany yield more characters for identification. Fossil cyperacean infructescences with in situ pollen are recognized for the first time and show features of the early-divergent mapanioid sedges. Pollen resembles that of tribe Hypolytreae. Comparisons with extant taxa suggest the closest affinities with Hypolytrum and Mapania. However, the Messel fossils represent a distinct taxon, Volkeria messelensis gen. et sp. nov. Without the additional characters of infructescence and pollen, the Messel fruits would have been placed in the extinct genus Caricoidea, a typical Eocene sedge that was widespread across Eurasia. Similarities of fruit structure suggest that Caricoidea was also a mapanioid sedge. Mapanioid sedges are found today in tropical wet forests and swamps, a distribution suggesting that early sedges occupied a similar habitat, unlike many modern sedges, and were not precursors to open grassland vegetation.     

Squamate reptiles from the middle Eocene of Lissieu (France). A landmark in the middle Eocene of Europe

In Europe, faunas of squamates (lizards and snakes) from the middle Eocene are very poorly known, with the exception of those from the level MP 16 (latest middle Eocene). From the MP 11-MP 15 interval, squamates were previously reported only from Messel (MP 11, earliest middle Eocene) and from the untere and obere Mittelkohle of Geiseltal (MP 12 and MP 13 respectively) in Germany. The present report describes the middle Eocene assemblage of squamates from Lissieu (France), the first fauna reported from the level MP 14. Whereas fossils from Messel and Geiseltal are mostly articulated skeletons, fossils from Lissieu are represented by disarticulated bones; such fossils may be more easily compared to those from other Cenozoic localities, in which bones are almost always disarticulated. The fauna from Lissieu is more diverse than those from the Geiseltal sites and approximately as diverse as that from Messel as they are presently known; it is comprised of 17 distinct taxa. These taxa cannot be all identified to the species or genus level. They belong to iguanids, gekkonids, lacertids, anguids, thecoglossan platynotans, ophidians incertaesedis, boids, ?tropidophiines, “tropidophiids” incertaesedis, booids incertaesedis, and perhaps russellophiids. The fauna includes several new taxa but only a presumed tropidophiine snake may be named on the basis of the available material. The fauna from Lissieu is a mixture of taxa restricted to the middle Eocene and taxa known from older or younger levels. Taxa shared by Lissieu and the few other localities from the middle Eocene of Europe are rare. This fauna from Lissieu represents a stratigraphical landmark for the middle Eocene.     

Taxonomic description of in situ bee pollen from the middle Eocene of Germany

The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera.     

Planktonic bloom-forming Cyanobacteria and the eutrophication of lakes and rivers

SUMMARY. 1. Eutrophication of water bodies involves the enrichment of plant nutrients, often followed by significant shifts in the phytoplankton towards Cyanobacteria. When comparing different aquatic systems, even with similar nutrient contents and in the same climatic region, inverse deductions are not valid; i.e. (a) the presence of Cyanobacteria does not necessarily indicate eutrophic conditions, or (b) eutrophic or even poly-trophic conditions do not necessarily support cyanobacterial development.
2. Above a threshold of 10 μg 1⁻¹ total phosphorus, the development of Cyanobacteria can be described by physical factors, such as water column stability. By characterizing different forms of turbulence, the presence or absence of Cyanobacteria in lakes and rivers can be predicted.
3.When the turbulence of the water column is rather low, as it is in sheltered or meromictic lakes, Cyanobacteria can build up dense populations. In nutrient poor systems, species of Oscillatoria and (seldom) Aphanizomenon are dominating.
4.If the turbulence of the water column is high (mixing depth much greater than euphotic depth) or the mixing pattern is irregular, as in slowly flowing or regulated rivers, Cyanobacteria are outcompeted.
5. In the presence of frequent or permanent turbulence, but with mixing depths lower or not much greater than the euphotic zone (as it is the case in shallow, unstratified lakes, mostly eutrophic or even hypertrophic), Cyanobacteria can outgrow normally dominant r -strategists under conditions of low N:P ratios, high water temperatures, pH >9.0 or low light availabilities.
6. If turbulence is comparatively great (10 to $15 m) and stable for a longer period of time, some cyanobacteria are able to adapt.
7. Our statements are discussed on the basis of physiological characteristics.     

THE EPIDEMIOLOGY AND CONTROL OF NOSEMA DISEASE OF THE HONEY-BEE

The proportion of honey-bees infected with Nosema apis (Zander) declines in summer as the old infected bees die, for they cease to transmit their infection to the newly emerged individuals during the flying season. N. apis spores survive the summer on combs contaminated with infected faeces during the preceding winter. Although bees clean the combs during the summer, all infected material is not removed, and even well-used brood comb, which has been repeatedly cleaned by bees, can carry infection. Only a few bees may contract infection in the autumn from these faeces, but they join the winter cluster and initiate the next outbreak of the disease. Transferring a colony on to clean comb early in the spring or summer removes the source of the disease, and it then disappears when all the old infected bees die.
Old broodless comb can be sterilized quite simply by fumigation for a few days with the vapours of formalin or glacial acetic acid. Acetic acid is preferable, because it does not poison any honey or pollen in the combs. Formaldehyde can safely be used only with empty combs.
The autumn is the best time for treating colonies chemotherapeutically, because the combs are then cleanest and the few bees which are infected can be cured during the winter. The drug can be incorporated in the syrup normally fed to colonies in autumn, and there is no risk of seriously contaminating subsequent honey crops. However, such treatment cannot eliminate the disease because sufficient spores remain on the combs for the disease to start again when the drug supplied in the winter stores is exhausted.     

Structural coloration in a fossil feather

Investigation of feathers from the famous Middle Eocene Messel Oil Shale near Darmstadt, Germany shows that they are preserved as arrays of fossilized melanosomes, the surrounding beta-keratin having degraded. The majority of feathers are preserved as aligned rod-shaped eumelanosomes. In some, however, the barbules of the open pennaceous, distal portion of the feather vane are preserved as a continuous external layer of closely packed melanosomes enclosing loosely aligned melanosomes. This arrangement is similar to the single thin-film nanostructure that generates an iridescent, structurally coloured sheen on the surface of black feathers in many lineages of living birds. This is, to our knowledge, the first evidence of preservation of a colour-producing nanostructure in a fossil feather and confirms the potential for determining colour differences in ancient birds and other dinosaurs.     

The early Eocene birds of the Messel fossil site: a 48 million‐year‐old bird community adds a temporal perspective to the evolution of tropical avifaunas

Birds play an important role in studies addressing the diversity and species richness of tropical ecosystems, but because of the poor avian fossil record in all extant tropical regions, a temporal perspective is mainly provided by divergence dates derived from calibrated molecular analyses. Tropical ecosystems were, however, widespread in the Northern Hemisphere during the early Cenozoic, and the early Eocene German fossil site Messel in particular has yielded a rich avian fossil record. The Messel avifauna is characterized by a considerable number of flightless birds, as well as a high diversity of aerial insectivores and the absence of large arboreal birds. With about 70 currently known species in 42 named genus‐level and at least 39 family‐level taxa, it approaches extant tropical biotas in terms of species richness and taxonomic diversity. With regard to its taxonomic composition and presumed ecological characteristics, the Messel avifauna is more similar to the Neotropics, Madagascar, and New Guinea than to tropical forests in continental Africa and Asia. Because the former regions were geographically isolated during most of the Cenozoic, their characteristics may be due to the absence of biotic factors, especially those related to the diversification of placental mammals, which impacted tropical avifaunas in Africa and Asia. The crown groups of most avian taxa that already existed in early Eocene forests are species‐poor. This does not support the hypothesis that the antiquity of tropical ecosystems is key to the diversity of tropical avifaunas, and suggests that high diversification rates may be of greater significance.     

全细胞多重PCR检测蓝藻、微囊藻及产毒微囊藻方法初探

选取三对分别针对微囊藻、蓝藻16S rDNA及微囊藻毒素合成酶基因mcyB的保守序列的特异性引物209F/409R、27F1/409R、MTR/MTF,其中409R为一条共用引物。设计并优化了一种可以同时检测蓝藻和微囊藻的两重全细胞PCR方法和一种可以同时检测蓝藻、微囊藻和可产毒微囊藻的三重全细胞PCR方法,并且测试了这两种PCR反应的灵敏度区间,分别为10⁵～10³cell·mL^-1、10⁵～10²cell·mL^-1。对采集水库水样检测结果表明双重全细胞PCR方法可以直接应用于对天然水样的检测,三重全细胞PCR方法可用于实验室培养藻细胞的筛查。全细胞多重PCR方法具有快速、简便、准确等特点,在水体微囊藻毒素检测预警方面具有应用价值。