Gradualistic characean lineages in the Upper Cretaceous–Palaeocene of southern Europe

Two charophyte lineages from the Upper Cretaceous–Palaeocene of southern Europe are described here, constituting a useful biostratigraphic tool for correlating non-marine stratigraphic sequences. The Peckichara pectinata lineage, ranging from the middle Campanian to the middle–upper Maastrichtian, consists of four successive gyrogonite morphotypes that displayed progressively more complex gyrogonite ornamentation and increasingly smaller gyrogonites with time. The Peckichara sertulata lineage, ranging from the middle Campanian to the Danian, consists of three morphotypes that followed a more common evolutionary trend, developing progressively larger gyrogonites without any changes in ornamentation. Intermediate forms between the successive morphotypes suggest that they corresponded to anagenetic varieties of the same evolutionary species rather than to separate species. The different trends observed appear to be palaeoenvironmentally controlled. The grades of the P. pectinata lineage first occurred in permanent lakes that later shifted to fluvial influenced floodplain ponds, this shift accounting for the reduction in gyrogonite size. By contrast, the P. sertulata lineage mainly occurred in permanent lakes, where stable palaeoenvironmental conditions enabled a steady rise in gyrogonite size to increase the space available for the zygote.     

New charophyte assemblage from middle Miocene lacustrine deposits of Moneva (Ebro Basin,Spain)

Two new fossil charophyte species from middle Miocene lacustrine deposits of Moneva (Ebro Basin, NE Spain) are described and illustrated. Sphaerochara miocenica nov. sp. is represented by medium sized gyrogonites with a characteristic spheroidal shape and ornamented with numerous small and regularly spaced tubercles arranged along the spiral cells. Several specimens show an unusual carbonate encrusted layer that covers completely or partially the gyrogonite. Psilochara monevaensis nov. sp. is characterized by large gyrogonites, with typical prolate shape and protruding apical poles. A second population of S. miocenica nov. sp. from a distant early upper Miocene lacustrine basin located in the Middle East (Bekaa Valley, Lebanon), identified in a previous study as Sphaerochara sp., is described and illustrated here, allowing the comparison of these distant populations. Ecologically, the associated fauna and facies from both localities suggest that these taxa grew in very shallow athalassic lakes. Interestingly, S. miocenica nov. sp. having a wide geographic distribution in peri-Mediterranean lakes with variable salinity, may become a fossil guide for the Miocene, providing at the same time important palaeoecological information.     

Reconstruction of the former charophyte community out of the fructifications identified in Albufera de València lagoon sediments

Several decades ago, due to eutrophication, Albufera de València lagoon lost the charophyte meadows that covered the bottom in the past but had never been studied in detail. An area close to the lagoon will be restored now to improve water quality and to recover submerged vegetation. To have information on the background of the charophytes from this area, four 80-87 cm long sediment cores were extracted from the lagoon. The subfossil charophyte fructifications (oospores and gyrogonites) were isolated and identified in two of the four cores. Moreover, sediment core fractions from the third and fourth cores were allowed to germinate under several conditions. The study of the lagoon sediments has revealed that at least 11 morphologies of charophyte fructifications existed in the past. Ten of these were determined at species level: Chara vulgaris, Chara hispida, Chara aspera, Chara baltica, Chara tomentosa, Chara globularis, Lamprothamnium papulosum, Nitella hyalina, Tolypella glomerata and Tolypella hispanica. However, one form of Chara gyrogonite did not fit in any known species. L. papulosum oospores and gyrogonites were the most abundant and concentrated in the deepest sediment layers when the lagoon held brackish water. Large changes in salinity due to freshwater input drove charophyte species substitution (disappearance of L. papulosum). During the oligohaline period C. vulgaris sexual propagules were the most abundant. The last charophyte community before its disappearance due to eutrophication was composed mainly of C. hispida, C. tomentosa and N. hyalina (the two latter with small numbers of oospores in the sediment). To characterize the morphology of the unidentified gyrogonite species, 100 specimens were studied. This type could be a local variety of a more common species, probably C. vulgaris, grown under particular ecological conditions. Old collected oospores (more than 45 years old) germinated and could be identified as C. vulgaris and C. hispida.     

Charophyte-rich microfacies in the Barremian of the Eastern Iberian Chain (Spain)

Non-marine carbonate microfacies based on charophytes are a useful palaeoenvironmental tool that has been poorly developed to date. In the Barremian of the Maestrat Basin (Eastern Iberian Chain), five such microfacies are described and interpreted in terms of sedimentology and palaeoecology: (1) Microfacies of clavatoracean remains are mudstones and wackestones rich in utricles and well-preserved charophyte thalli of the genus Clavatoraxis, representing in situ deposition of clavatoracean meadows. (2) Microfacies of filamentous algae and clavatoraceans are mudstones with a high proportion of calcified filaments attributed to cyanobacteria and green algae. This facies may correspond to the open lake benthos. (3) Microfacies of Intraclasts and Charophyte remains are packstones formed on the shores of freshwater lakes or brackish swamps that underwent subaerial desiccation and wave reworking. (4) Microfacies of Porocharacean remains are wackestones and packstones with abundant gyrogonite fragments of genus Porochara. They are related to the reworking of a porocharacean meadow in shallow brackish marshes. (5) Microfacies of Munieria grambasti Bystricky 1976 fragments are grainstones attributed to the reworking of Munieria-dominated meadows. In consequence to these results, a palaeoecological model based on charophyte remains is proposed as a useful tool in carbonate facies analysis.     

Oospore dimensions and morphology in North American Tolypella (Charophyceae,Charophyta)

Characteristics of the oospores have been used to delimit sections and, in some cases, species in the genus Tolypella A. Braun. To test the utility of oospore characters for identifying North American species of Tolypella, we investigated oospores from field‐collected and herbarium specimens. Oospore dimensions (length, width, and length to width ratio) and morphology (color, ridge number and shape, wall ornamentation, and basal impression number) were measured. Oospore dimensions were statistically analyzed and oospore morphology was studied with light and scanning electron microscopy. Statistical analyses showed significant differences in length, width, and length to width ratios among most Tolypella species and populations but there was considerable overlap, which suggested that species identification based on oospore measurements alone is not wholly reliable. In addition, oospore morphology was not unique for every species.     

Paleoenvironmental and paleobiogeographical implications of the microfossil assemblage from the Late Cretaceous intertrappean beds of the Manawar area,District Dhar,Madhya Pradesh,Central India

Abstract

An assemblage of microfossils consisting of non-marine ostracods (Cypridopsis, Gomphocythere, Zonocypris, Eucypris, and Frambocythere), charophyte gyrogonites (Platychara), molluscs (Viviparus, Valvata, and Lymnaea), and fish remains (mainly Phareodus), is here reported from a new intertrappean locality near the town of Manawar, District Dhar, Madhya Pradesh, Central India. The biotic component recovered suggests a Late Cretaceous (Maastrichtian) age for the intertrappean deposit near Manawar. Paleoenvironmentally, the overall biotic assemblage recovered indicates the presence of a freshwater palustrine/lacustrine depositional system connected to a low energy stream/river. Paleobiogeographically, the known high diversity of ostracod genera, especially Eucypris, Cypridopsis, and Gomphocythere, hints at endemism within the Indian Subcontinent during the Late Cretaceous (Maastrichtian). However, the cosmopolitan distribution of the charophyte genus Platychara in the K-Pg interval across the globe (Africa, Europe, and America) and its absence in the Upper Cretaceous of China and Mongolia is quite intriguing.     

New insights into Paleozoic charophyte morphology and phylogeny

Examination of Paleozoic charophyte fructifications using microscopy and high-resolution x-ray synchrotron microtomography has revealed that most of them have a utricle that forms a supplementary calcified cover around the gyrogonite. All Paleozoic families with utricles have been assigned to the Sycidiales. We consider the Moellerinaceae to occupy a central position in the phylogeny of the Charophyta. From these, one group of descendants constitutes the gyrogonites inside the utricles of the Sycidiales; a second descendant goup is thought to be the utricle-free ancestors of the Charales prior to inversion of spiralization and reduction in cell number. The Sycidiales have a multilayered wall and an internal vesicle, but their families are distinguished by diversity in orientation of external cells, complexity of the utricle wall, and in presence or absence of antheridia. The solidly packed structure of the utricle is believed to be an organ protecting the zygote against dessication. We interpret the morphological similarities between Paleozoic Sycidiales and Mesozoic Clavatoraceae, both with a utricle, as homoplasous rather than expressing a true phylogenetic relationship. We confirm that some umbellids might correspond to utricles of charophytes.     

Oospore Wall Ornamentation in the Genus Tolypella (Charales,Charophyceae)

The ultrastructural features of oospore wall ornamentation in the genus Tolypella were examined using scanning electron microscopy (SEM). The taxonomic relationships among several species were discussed on the basis of oospore ultrastructure and measurements. In the case of T. glomerata and T. nidifica, our results support the status of separate species. Close relationships and transitional forms may exist between T. nidifica and T. normaniana, and not only in oospore wall ornamentation. Oospores of T. hispanica exhibited the same distinct type of reticulate oospore wall as previously reported, but our results do not support the recognition of T. hispanica as a separate species. Ultrastructure of the oospore walls of T. prolifera and T. intricata was almost identical, suggesting that these species are closely related. We therefore reject previous suggestions that morphological characteristics of oospores as observed in SEM are sufficient for identification of individual species. Although significant differences were found among oospores in individual species of Tolypella, large variation among populations, and among individuals belonging to the same population, caused substantial overlap among species.     

The colubrid radiation in Africa (Serpentes: Golubridae): phylogenetic relationships and evolutionary patterns based on immunological data

Phylogenetic relationships among genera of African colubrids were evaluated using estimates of divergence among serum albumins compared by microcomplement fixation. Representatives of about half of the extant genera of African colubrids, as well as the Elapidae, Atractaspis and the Madagascan colubrid Leioheterodon, were analysed. The tree of best fit to the data has an unresolved basal polychotomy comprising at least five lineages of colubrids, as well as Elapidae and Atractaspis; thus, colubrids were not demonstrably monophyletic with these data. Two cosmopolitan clades, colubrines and natricines, are represented in Africa by series of closely related genera, but divergence among other genera is relatively great. Rate tests show that this is apparently not due to higher rates of albumin evolution in these, relative to other colubrids. Among the other associations supported by the immunological data are: (1) Psammophis-(Rhamphiophis-Dipsina)-Malpolon-Psammophylax; (2) Amblyodipsas-Macrelaps; (3) (Lycodonomorphus-Lamprophis)-Mehelya; and (4) Colubrinae-Natricinae. Grayia is questionably associated with the colubrine-natricine lineage. Prosymna and Lycodon are clearly members of the colubrine clade, and Amplorhinus possibly associates with Leioheterodon. Gonionotophis, Duherria, Lycophidion and Pseudaspis show no strong association with any other genera, and represent other basal or near-basal clades within the colubrid/elapid radiation. The immunological data do not support a clade comprising the Elapidae, Atractaspis and some ‘aparallactines’ relative to Viperidae and other colubrids. The basal colubrid-elapid-Atractaspis divergence occurred more than 30 Myr ago, and the fossil record of colubrids in Africa greatly underestimates both the age and clade diversity of this group. In contrast to the pattern of radiation in the neotropics, where most colubrids belong to one of three major clades, in Africa only the colubrine lineage comprises a substantial portion of the extant generic diversity; most other genera stem from relatively ancient cladogenetic events and have few living representatives.     

Reanalysis of the biogeographical hypothesis of range expansion between robust and gracile capuchin monkeys

The data used by Lynch Alfaro et al. (2012a, Journal of Biogeography, 39 , 272–288) and the biogeographical hypothesis postulated by these authors to explain the current distribution of capuchin monkeys were reanalysed including additional cytochrome b data from Sapajus xanthosternos and Sapajus flavius. Our reconstructed phylogeny placed S. xanthosternos in a monophyletic clade representing the most basal lineage of this genus. All analyses indicated polyphyletic arrangements for several capuchin species, suggesting that incomplete lineage sorting has occurred during their evolution. These results also suggest that available molecular data lack adequate variation for accurately resolving species relationships. These results suggest that the divergence of capuchin monkey genera may have occurred in the Atlantic Forest. However, a more conclusive scenario and better resolution of the species tree requires correct identification of species, data from several unlinked nuclear loci from a higher number of individuals per species, and careful analysis of ancient DNA data from museum specimens.     

Phylogenetic relationships of the Chinese Labeoninae (Teleostei,Cypriniformes) derived from two nuclear and three mitochondrial genes

Zheng, L‐P., Yang, J‐X., Chen, X‐Y. & Wang, W‐Y. (2010) Phylogenetic relationships of the Chinese Labeoninae (Teleostei, Cypriniformes) derived from two nuclear and three mitochondrial genes. —Zoologica Scripta, 39, 559–571. The majority of genera within the Labeoninae occur in the South of China and the phylogeny of the subfamily Labeoninae has been a controversial topic over the years. The early and more recent phylogenetic results based on morphology are not in agreement, and some of the molecular analyses contradict those based on morphology. However, none of the previous studies has included an extensive sampling of Labeoninae genera. In this study, partial sequences of two nuclear (exon 3 of recombination activating protein 1 and rhodopsin) and three mitochondrial genes (cytochrome b, cytochrome oxidase subunit I and 16S ribosomal RNA) from 39 ingroup taxa and 11 outgroup taxa were used analysed to provide a hypothesis of phylogenetic relationships within the Chinese Labeoninae. The results supported the monophyly of Labeoninae and refuted the subdivision within Labeoninae based on the oromandibular morphology. It also further confirmed that the presence of a disc on lower lip arose through convergent evolution. Labeo was the basal clade and Osteochilus was closely related to Cirrhinus, forming the second basal clade. The monophyly of Garra and Bangana was refuted in this study, and they were both subdivided into two lineages. One lineage of Garra had closer relationships with Crossocheilus and Akrokolioplax, and the other lineage had closer relationships with Placocheilus. One lineage of Bangana represented the species with broadly interrupted postlabial groove; these species represented the true Bangana. The other lineage of Bangana included the species with continuous postlabial groove, and these species should be assigned to a new genus. Discogobio, as currently conceived, was paraphyletic, but it rendered monophyletic with the inclusion of Discocheilus. These results indicated that Discocheilus should be synonymised with Discogobio. Hongshuia and Sinocrossocheilus, respectively, formed independent lineages related to a lineage consisting of Pseudocrossocheilus plus seven other nominal genera. The relationships received weak support, but the repeatability of the clades could form the basis of recognising only the three genera mentioned above.     

塔里木盆地井下石炭纪轮藻植物群兼论古生代轮藻的分类

石炭纪轮藻化石比较罕见,本文论述了塔里木盆地井下大量的石炭纪输藻化石,同时发现了南,北两个不同的轮藻植物群,这些资料对其演化,分类的研究具有重要意义。     

Stable isotopes (δC and δO) of charophyte gyrogonites: example from the Brochene Fluh section (Late Oligocene-Early Miocene, Switzerland)

A synthetic curve based on the δ¹³C and δ¹⁸O variation measured on Oligocene-Miocene charophyte gyrogonites is presented. Such a synthetic curve cannot be interpreted without taking into account facies relationships. Thus, we present a detailed analysis of the Brochene Fluh section (Late Oligocene, MP29, to early Miocene, MN1), in which more than 30 charophytes levels have been recorded. It is possible to subdivide the section into six cycles: cycles one to four, Late Oligocene in age, present a covariance in the δ¹³C and δ¹⁸O variation, and are typical of small closed lakes subject to great seasonal changes (especially humidity). The last two cycles, of Aquitanian age, show a diminution of seasonality perhaps due to the ingression of the future Burdigalian sea.     

Chara zeylanica Wildenow（现生轮藻）藏卵器几个特征的统计分析

本文对采自广西涠洲岛的现生轮藻Ｃｈａｒａ ｚｅｙｌａｎｉｃａ藏卵器的几个特征作了统计分析,结果表明,藏卵器的最大长度,最大宽度和螺旋环数等性状的变异有一定范围,服从统计规律,单变量的变化呈正态分布,具一明显峰值;ＬＰＡ是ＬＥＤ的线性函数,呈正相关。藏卵器乌黑细胞的钙化程度与成熟度有关。未成熟藏卵器的顶部构造为典型的轮藻型,成熟藏卵的顶部构造与有盖轮藻型接近。因此认为,Ｃｒａｍｂａｓｔｉｃｈａｒａ     

哈萨克斯坦斋桑盆地新生代轮藻植物组合

斋桑盆地自晚白垩世以来即为淡水湖泊环境,其始新世至中新世湖相及湖边缘相沉积物产有丰富的轮藻化石。文中建立三个轮藻化石组合：(1)Harrisichara mitella—Peckisphaera zajsanica组合(中始新世早期);(2)Lychnothamnus formosus—Peckichara组合(中始新世晚期--渐新世早期);(3)Gyrogona aralica—sphaerochara clearus组合(中--晚渐新世)。斋桑盆地轮藻化石出现的最高层位为下中新统且化石稀少,推测系盆地环境日益干旱所致。     

Tectonic vicariance versus Messinian dispersal in western Mediterranean ground beetles

The complex geological history of the western Mediterranean region conceals the interpretation of the evolutionary history of its current fauna, as similar distribution patterns may have very different temporal and geographic origins. Particularly intriguing are some subterranean species in islands, which origin is usually difficult to interpret as their strongly modified morphologies obscure their relationships. We studied subterranean taxa and their likely relatives of two groups of ground beetles in the western Mediterranean: the Duvalius lineage (“isotopic” Trechini) and Molopina (Pterostichini). We included specimens from the islands of Mallorca, Sardinia and Sicily, plus mainland Europe and North Africa. Phylogenetic relationships were reconstructed with a combination of mitochondrial and nuclear data, and divergence dates were estimated with Bayesian methods using the same a priori molecular evolutionary rates for the same gene fragments in the two groups. In the Duvalius lineage, the subgenus Trechopsis, including all the highly modified cave or nivicolous species, was found to be polyphyletic: the species from Mallorca was found to be of Pleistocene origin and sister to the less modified species of subgenus Duvalius from the same island, whereas the Algerian species of Trechopsis were, on the contrary, related to the Sicilian Duvalius, indicating a northern colonisation route during the late Pliocene. Molopina was divided into three main lineages: the genera Abax, Percus, and the Molops groups of genera. The basal diversification of the latter was dated within a temporal window (35–25 Ma) fully congruent with the tectonic opening of the western Mediterranean basin and included six main lineages with uncertain relationships among them: the epigean genera (a) Molops and (b) Tanythrix; and the subterranean (c) Typhlochoromus (Eastern Alps), (d) Speomolops (Sardinia), (e) Henrotius (Mallorca) and (f) a strongly supported clade including the Pyrenean genera Zariquieya, Oscadytes and Molopidius. Despite the similar distribution of some of their subterranean taxa, the two studied groups show a strongly contrasting origin and mode of diversification. While the Duvalius lineage had a recent origin, with complex colonisation patterns and widespread morphological convergence among the subterranean species, the subterranean Molopina had an ancient vicariant origin resulting from the tectonic opening of the western Mediterranean basin.     

PHYLOGENY OF THE CONJUGATING GREEN ALGAE BASED ON CHLOROPLAST AND MITOCHONDRIAL NUCLEOTIDE SEQUENCE DATA1

The conjugating green algae represent a lineage of charophyte green algae known for their structural diversity and unusual mode of sexual reproduction, conjugation. These algae are ubiquitous in freshwater environments, where they are often important primary producers, but few studies have investigated evolutionary relationships in a molecular systematic context. A 109‐taxon data set consisting of three gene fragments (two from the chloroplast and one from the mitochondrial genome) was used to estimate the phylogeny of the genera of the conjugating green algae. Maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) were used to estimate relationships from the 4,047 alignable nucleotides. This study confirmed the polyphyly of the Zygnemataceae and Mesotaeniaceae with respect to one another. The Peniaceae were determined to be paraphyletic, and two genera traditionally classified among the Zygnematales appear to belong to the lineage that gave rise to the Desmidiales. Six genera, Euastrum, Cosmarium, Cylindrocystis, Mesotaenium, Spondylosium, and Staurodesmus, were polyphyletic in this analysis. These findings have important implications for the evolution of structural characteristics in the group and will require some taxonomic changes. More work will be required to delineate lineages of Zygnematales in particular and to identify structural synapomorphies for some of the newly identified clades.     

Huia caspica gen. & comb. nov., a dinoflagellate species that recently crossed the marine‐freshwater boundary

The dinoflagellate subfamily Diplopsalidoideae encompasses 11 genera whose plate patterns show a large diversity. In a recently published molecular phylogeny (Liu et al. 2015) some of these genera (e.g. Diplopsalis, Diplopelta) are polyphyletic, suggesting that further subdivision of these genera is needed. Here we established the cyst‐theca relationship of Diplopsalis caspica by incubating cysts collected from the East China Sea. Cells of D. caspica display a plate formula of Po, X, 3′, 1a, 6″, 3c+t, ?4s, 5″′, 1″″, characterized by a small, parallelogrammic anterior intercalary plate (1a) located in the middle of the dorsal part of the epitheca. The cysts are spherical and smooth‐walled with a theropylic archeopyle. In addition, we obtained four large subunit ribosomal DNA (LSU rDNA) sequences from the germinated motile cells by single‐cell polymerase chain reaction. Strains of D. caspica from the marine environment of the East China Sea differ at 0–2 positions of LSU rDNA sequences from that of lacustrine strains from NE China. In the molecular phylogeny, D. caspica was close to Lebouraia pusilla but distant from D. lenticula, the type species of Diplopsalis. Our results support the systematic importance of plate 1a, and therefore D. caspica was transferred to a new genus, Huia. The conservative LSU rDNA sequences in H. caspica suggest that the marine‐freshwater transition occurred recently.     

Biogeography of living and fossil Nitellopsis (Charophyta) in relationship to new finds from Morocco

Aim To document the distribution of two closely related macrophyte species, the fossil Nitellopsis (Tectochara) merianii (A. Braun ex Unger) Grambast & Soulié‐Märsche and Nitellopsis obtusa (Desvaux) J. Groves, the single living species of genus Nitellopsis and to draw the relationships between first finds of N. merianii in North Africa and previously known records. Location South part of the High Atlas Range, Aït Kandoula basin, Morocco. Methods New finds of fossil charophyte gyrogonites were determined and illustrated. Using a large bibliographic database of both fossil and extant charophytes, we depict the biogeographical distribution N. merianii and N. obtusa and summarize the ecological requirements of N. obtusa as a modern analogue. Results The Aït Kandoula deposits, dated by magnetostratigraphy and vertebrate fossils to Upper Miocene, provided the first fossil populations of N. merianii in Africa. The distribution patterns of the Tertiary N. merianii and the living N. obtusa superimpose on a large area that extends from Spain to East Asia and characterize them as typically Eurasian taxa indicative for permanent, relatively cold and deep freshwater lakes. During the Quaternary, similar palaeolakes in the Sahara were colonized by N. obtusa. Main conclusions The presence of the Eurasian species N. merianii in North Africa is the result of dispersal by migratory waterbirds and attests to N–S migration occurring during the Upper Miocene (10–5 Myr ago). Gyrogonites imported from Southern Europe could germinate and fulfil their life cycle so as to form a new seed bank of gyrogonites because they had been deposited in a suitable environment consisting of a freshwater mountain lake.