Biometry of Upper Cretaceous (Cenomanian–Maastrichtian) coccoliths – a record of long-term stability and interspecies size shifts

Biometric measurements of Mesozoic coccoliths (coccolith length and width) have been used in short-term biostratigraphic, taxonomic and palaeoecologic studies, but until now, not over longer time scales. Here, we present a long time-series study (∼ 30 million years) for the Upper Cretaceous, which aims to identify broad trends in coccolith size and to understand the factors governing coccolith size change over long time scales. We have generated biometric data for the dominant Upper Cretaceous coccolith groups, Broinsonia/Arkhangelskiella, Prediscosphaera, Retecapsa and Watznaueria, from 36 Cenomanian–Maastrichtian (100.5–66 Ma) samples from Goban Spur in the northeast Atlantic (DSDP Site 549). These data show that the coccolith sizes within Prediscosphaera, Retecapsa and Watznaueria were relatively stable through the Late Cretaceous, with mean size variation less than 0.7 μm. Within the Broinsonia/Arkhangelskiella group there was more pronounced variation, with a mean size increase from ∼ 6 μm in the Cenomanian to ∼ 10 μm in the Campanian. This significant change in mean size was largely driven by evolutionary turnover (species origination and extinctions), and, in particular, the appearance of larger species/subspecies (Broinsonia parca parca, Broinsonia parca constricta, Arkhangelskiella cymbiformis) in the early Campanian, replacing smaller species, such as Broinsonia signata and Broinsonia enormis. Shorter-term size fluctuations within Broinsonia/Arkhangelskiella, observed across the Late Cenomanian–Turonian and Late Campanian–Maastrichtian intervals, may, however, reflect changing palaeoenvironmental conditions, such as sea surface temperature and nutrient availability.     

基于28S, COI和Cytb基因序列的薜荔和爱玉子传粉小蜂分子遗传关系研究

薜荔和爱玉子均属于桑科榕属植物,二者为同一物种的原变种与变种的关系,早期研究认为这两种榕树与同一种传粉榕小蜂(Wiebesia pumilae (Hill))建立了稳定的互利共生关系,但近期在形态学、生态学、传粉生物学等方面对二者的研究结果表明,薜荔传粉小蜂和爱玉子传粉小蜂之间可能发生了遗传分化。实验用核糖体28SrDNAD1-D3区、线粒体Cytb及COI基因部分序列,对采自福建3个不同样地的薜荔传粉小蜂和3个不同品系的栽培爱玉子的传粉小蜂进行分析,结果表明:(1)薜荔传粉小蜂和爱玉子传粉小蜂的核糖体28S序列的碱基组成中A,T,G,C 4种含量较平均,C+G的平均含量(56%)稍高于A+T的含量(44%)。线粒体Cytb序列中A+T的含量(76.1%)明显高于C+G的含量(23.9%),COI序列中A+T的含量(71.9%)也明显高于G+C的含量(28.1%),这是膜翅目昆虫线粒体基因的普遍特征。在薜荔和爱玉子传粉小蜂的线粒体Cytb及COI基因中,密码子第三位点A+T的含量最高。(2)比较薜荔和爱玉子传粉小蜂的3种分子标记的变异范围显示,28S进化速度较Cytb及COI序列慢,比较保守,更适合科、亚科等较高分类单元的研究。薜荔传粉小蜂与爱玉子传粉小蜂之间的亲缘关系较近,采用Cytb与COI序列进行分析更为精确。(3)用Cytb及COI序列对薜荔传粉小蜂与爱玉子传粉小蜂之间的遗传距离进行分析显示,薜荔传粉榕小蜂个体间Cytb序列平均遗传距离为0.0054,爱玉子传粉小蜂个体间的Cytb遗传距离为0.0164;薜荔传粉小蜂与爱玉子传粉小蜂群体之间的Cytb序列平均遗传距离为0.1385;COI序列的薜荔传粉榕小蜂个体间遗传距离为0.0048,爱玉子传粉小蜂各样本间平均遗传距离为0.0102;薜荔传粉小蜂与爱玉子传粉小蜂群体间COI序列平均遗传距离为0.1896,两群体间的遗传距离(差异大于10%以上)明显大于群体内各样本之间的遗传距离,表明薜荔传粉小蜂与爱玉子传粉小蜂之间已经发生了很大的遗传分化,其变异水平达到了种间分化水平,即薜荔传粉小蜂与爱玉子传粉小蜂为两个不同的种。     

A Late Miocene Paratethyan mollusc fauna from the Denizli Basin (southwestern Anatolia, Turkey) and its regional palaeobiogeographic implications

We report on a Late Miocene mollusc fauna from a single locality in the Denizli Basin in southwestern Turkey that is composed of ten presumably euryhaline species and three freshwater species. The fauna is remarkably distinct from faunas of the adjacent Late Miocene Aegean and Euxinian Basins, and has elements in common with the modern Caspian Sea fauna in the form of Didacna species. The suggested age of the fauna (Late Miocene) would extend the stratigraphic range of the lymnocardiid genus Didacna (hitherto Calabrian-Extant) considerably. The palaeobiogeographic significance of the Denizli fauna is discussed.     

Paleoenvironmental controls on the morphology and abundance of the coccolith Watznaueria britannica (Late Jurassic,southern Germany)

The coccolithophore species Watznaueria britannica is dominant in Middle-Upper Jurassic calcareous nannofossil assemblages and presents morphological variation, including different coccolith size, shape and length of the central area and of the bridge. Six morphotypes can be recognized in the polarizing light microscope. The aim of this work is to better understand the morphological variability of W. britannica and determine if this variability is controlled by paleoecological factors. In order to investigate the potential paleoecological controls on W. britannica morphology and abundance, we carried out a biometric study on a restricted temporal interval: the Late Oxfordian, in the Swabian Alb (southern Germany), characterized by increasing carbonate production linked to climatic changes. The Balingen–Tieringen section, where previous works on sedimentology, nannofossil assemblage composition, and δ¹⁸O and δ¹³C analyses were performed, was selected for this study. The variations in morphology and abundances of W. britannica were studied on 40 samples of the Balingen–Tieringen section, presenting variable lithologies and calcium carbonate contents. For each level, seven biometric parameters (coccolith length, width and ellipticity, central area length, width and ellipticity and central area proportion with respect to the coccolith) were measured or calculated on digitally captured images of the first 100 W. britannica coccoliths observed in the light microscope. The relationships between the different biometric variables were described using bivariate and Principal Component Analyses. Biometric parameters and Principal Component factors extracted from nannofossil assemblages as well as other paleoenvironmental proxies, were investigated using regression, and their stratigraphic trends were compared. Principal component analysis of the six biometric variables (3938 measurements) on W. britannica coccoliths shows a reduced morphological variability compared to a significant size gradient. An allometric trend recognized on the total placolith and on the central area within the W. britannica assemblages suggests that the different morphotypes may represent intra-specific variability rather than different species. The general trend through Late Oxfordian shows an increase in size of W. britannica coccoliths, mainly driven by an increase in the contribution of the large morphotypes. Increasing placolith size is associated with drier and warmer climatic conditions during the latest Oxfordian.     

Taxonomy of reproductive Nereididae (Annelida) in multispecies swarms at Ambon Island,Indonesia

Multispecies, or mass, spawning of different invertebrate species is well known for coral reef systems; however, incidences involving polychaetes are poorly documented. In this study we report on mass swarming, prior to spawning, of Nereididae at Ambon Island, Maluku, on three occasions: in 1866, inferred from an historical sample deposited in Naturalis, Leiden, and in March, 2009 and 2014, based on newly collected samples. The 2009 and 2014 events co-occurred with spawning of other polychaetes, known locally as wawo and including the widespread Indo-Pacific eunicid, Palola viridis (Gray in Stair). Ten species of reproductive Nereididae are described, including Composetia marmorata (Horst) new combination, formerly Ceratonereis marmorata; epitokous modifications are described for both sexes of each species including taxonomically important features such as body colour and number of pre-natatory chaetigers. Three distinct types of natatory region morphologies are recognized, which appear to characterise groups of genera. The ten new records brings to 13 the total number of nereidid species known to undergo mass swarming at Ambon Island; a key to the 13 species is provided. Species composition varies slightly between the three time periods: four species were common between all three periods, five species were in common between 1866 and 2014, and four species were in common between 1995 and 2009/14. Two species of Neanthes and one of Nereis are identified as potentially new and will be described in subsequent papers.     

Systematic revision and sexual dimorphism in Choffatia (Ammonoidea: Perisphinctoidea) from the Callovian of Kutch,India

The genus Choffatia (Siemiradzki) is an important Callovian ammonite in Kutch biostratigraphy. Several species of the genus were described by the early workers who did not recognize intraspecific variability and sexual dimorphism in terms of the modern concepts. We have described here three dimorphic species based on material reposited in the Geological Survey of India, Kolkata as well as systematically collected additional specimens with precise stratigraphic information. These species are: Choffatia recuperoi (Gemmellaro, 1873), Choffatia cobra (Waagen, 1875), and Choffatia perdagata (Waagen, 1875). The microconchs of the three species, described here for the first time, are lappeted whereas the macroconchs have a simple aperture. However, these species have similar shell morphologies and they intergrade in shell shape and sculpture; thus it is difficult to distinguish them qualitatively. Statistical analyses (both bivariate and multivariate) support that they are distinct species and there is a good correlation among the degree of involution, the degree of inflation, and the strength of ornamentation. C. cobra is the most evolute, depressed, and strongly ribbed whereas C. perdagata is the most involute, compressed, and weakly ribbed. C. recuperoi occupies the intermediate position. This interspecific diversity of Choffatia thus supports Buckman's Law of Covariation.     

Essential oil composition of nine Apiaceae species from western United States that attract the female Indra Swallowtail butterfly (Papilio indra)

Aletes acaulis, Cymopterus hendersonii, Cymopterus panamintensis var. acutifolius, Lomatium rigidum, Lomatium scabrum var. tripinnatum, Musineon tenuifolium, Sphenosciadium capitellatum, Tauschia arguta and Tauschia parishii are among the twenty-two species of the Apiaceae family to which female Indra Swallowtail butterflies (Papilio indra: Lepidoptera) are attracted for oviposition. Because plant volatile oils are known to be attractants for female butterflies, the percent composition of the essential oils of each species was studied. Amongst the nine host plants 168 essential oil components were identified representing between 84% and 99% of the oils. Principal Components Analysis and hierarchical cluster analysis on the essential oil compositions of the larval host plants against four non-larval host plants separated the hosts from the non-hosts into distinct clusters. Volatile components of the oils common to the nine species of Apiaceae are correlated with the expression of physiological attraction behavior by the butterfly.     

Evolution of the coccolith genus Lotharingius during the Late Pliensbachian-Early Toarcian interval in Asturias (N Spain). Consequences of the Early Toarcian environmental perturbations

The evolution of the coccolith genus Lotharingius was investigated in 18 samples from the West Rodiles section (Asturias, Northern Spain), Upper Pliensbachian-Lower Toarcian in age. In each sample, the length and width of the coccolith and of its central area were measured on 150 specimens of Lotharingius. A total of 2700 specimens were measured, and 10,800 measurements were obtained. Based on the results of the morphometric analysis, the stratigraphic ranges, the abundance patterns and the light microscope observations, the aims of this work are to determine whether the specimens analysed correspond to different species, to distinct ecophenotypes or to an anagenetic lineage of morphotypes of a single species with overlapping stratigraphic ranges, and to test the influence of the paleoenvironmental perturbations during the Early Toarcian on the studied genus. Three species of Lotharingius were distinguished: L. hauffii, L. sigillatus and L. crucicentralis. Based on central area size and structure, two morphotypes (A and B) of L. hauffii were differentiated. All the parameters measured show a great overlap between the morphotypes and species. An increase in both coccolith and central area size and a development of more complex central area structures were observed through the studied section. L. hauffii is the smallest form, followed by L. sigillatus, and finally L. crucicentralis is the largest species and has the most complex central area structure. A clear decrease in size or “dwarfing” of the species was observed in the samples corresponding to the Early Toarcian environmental perturbations. L. crucicentralis was not identified in these samples. We hypothesize that the changes in size and abundance of the Lotharingius species could be related to the unfavourable palaeoenvironmental conditions for the biomineralization of their coccoliths.     

Four powdery mildew species with catenate conidia infect Galium: molecular and morphological evidence

The Erysiphaceae are a group of obligately biotrophic fungi that cause powdery mildew disease of angiosperms. Due to their inability to be cultured on artificial media, the taxonomy of the Erysiphaceae has generally been based on the morphological characteristics of fresh and herbarium specimens. Thus, several morphological species with wide host ranges have long been maintained in this family, even though they clearly consist of several biological species. Erysiphe galii has been known as a powdery mildew of Galium spp. Recently, the former E. galii var. galii has been reassessed as Neoerysiphe galii and E. galii var. riedliana as Golovinomyces riedlianus, along with a taxonomic revision of the generic concept of the Erysiphaceae. The present study was conducted to evaluate the validity of the taxonomic revision of the two varieties of E. galii. During the course of this study, we found that the Galium powdery mildews consist of at least four different species, viz. Neoerysiphe galii, Golovinomyces orontii, G. riedlianus, and an unknown species collected in Argentina. The latter species is described as a new species, Golovinomyces calceolariae. The three species belonging to Golovinomyces are morphologically very similar to each other, i.e. the discrimination between them is rather difficult. The morphological differences of the three Golovinomyces species of Galium are discussed.     

Molecular Polymorphism and Morphometrics of Species of the Heterodera avenae Group in Syria and Turkey

Molecular characterization of the three most common cereal cyst nematode species of the Heterodera avenae group (H. avenae, H. filipjevi, and H. latipons), originating from various locations in major cereal-cultivating areas in Syria and Turkey, showed distinct restriction fragment patterns of the ITS-rDNA following PCR amplification and RFLP digestion with four endonucleases (Hae III, Hinf I, Ita I, and Pst I). Genetic dissimilarity within H. avenae group populations increased in comparison with H. avenae and other species; it was 0.164 with H. filipjevi and 0.354 with H. latipons populations. No intraspecific polymorphism was observed within H. latipons or H. filipjevi populations. Principal component analysis revealed contrasted correlations among 12 morphological parameters of cysts and juveniles of the three Heterodera species that separated them and distinguished differences within populations of H. latipons. Our results showed a clear separation of the three cyst nematode species on cereal using a conventional method for classification and molecular tests, and confirmed the congruence between genetics and morphological traits.     

Flavonoid chemistry of Coreopsis grandiflora (Compositae)

The leaf flavonoid chemistryof Coreopsis grandiflora, which includes var.harveyana, var.longipes, var.saxicola and the typical var.grandiflora, is quite uniform with 6-hy-droxyquercetin 7-O-glucoside, luteolin 7-O-glucoside, marein-maritimein chal-cone-aurone pair and lanceolin-leptosin chalcone-aurone pair as consistent com-ponents. Flavonoid data lend support to the hypothesis that the hexaploid var.longipes originated from parents which would be included withinC. grandiflora, i.e., there is no evidence that other species were involved in its formation. One population of var.grandiflora and several collections of var.saxicola contain additional flavonoid components in the form of flavonol 3-O-glycosides. In nearly all instances the additional compounds are attributable to hybridization withC. lanceolata orC. pubescens because these flavonols are characteristic of these two species and morphological considerations also suggest it. Flavonoid chemistry supports the treatment of var.saxicola as a variety ofC. grandiflora rather than as a distinct species.     

Unusual iridoid glycosides in Veronica sects. Hebe and Labiatoides

In a chemosystematic investigation of three Southern hemisphere species of Veronica, namely the Australian Veronica derwentiana Andrews and Veronica perfoliata R.Br. (formerly Derwentia species), and the New Zealand Veronica catarractae G. Forster (formerly a species of Parahebe), the water-soluble constituents were isolated and identified by spectroscopic methods. Apart from other iridoid glucosides common to the genus, three unusual substituted benzoyl esters of aucubin (derwentiosides A–C) were obtained from V. derwentiana and a chlorinated iridoid glycoside (catarractoside) from V. catarractae in addition to other iridoids common to the genus. The chemical profile of V. perfoliata is similar to that of Northern hemisphere species of Veronica because of the presence of characteristic 6-O-catalpol esters. The profile of V. derwentiana is unique, since 6-O-esters of aucubin rather than of catalpol dominate, however, the acyl groups are the same as those present in catalpol esters found in some other Veronica sections. V. catarractae also contains one of the catalpol esters characteristic of Veronica, but in addition three 6-O-rhamnopyranosyl substituted iridoid glycosides, one of which is 6-O-rhamnopyranosylcatalpol. Esters of the latter compound are previously only known from the more derived species in recent phylogenetic trees of sect. Hebe to which V. catarractae now also belongs, but as a more basal member.     

Acacia gum exudates from species of the series gummiferae

An analytical study of the gum exudates from the African species Acacia ehrenbergiana (three specimens), A.xanthophloea (two specimens), A.hockii and A.sieberana var.villosa, and of the Australian species A.calcigera, has been made. There are now 19 species within the series Gummiferae Benth. for which gum parameters are available; of these, only A. ehrenbergiana gum displays a slightly negative optical rotation. The data for the three gum specimens from A. ehrenbergiana give a further example of the extent to which the gum from different trees of one particular species can vary in composition. The data for A.sieberana var. villosa gum are compared with the values established previously for subsp. sieberana; the differences between varieties of one species are similar in extent to those established for some subspecies. Although A. xanthophloea, A. hockii, A. ehrenbergiana, A. seyal and A. karroo are regarded as being very closely related botanically, the values for some of their analytical parameters differ considerably and strongly support the view that it is correct to retain them as distinct species.     

Genetic analysis of southern African gemsbok (Oryx gazella) reveals high variability, distinct lineages and strong divergence from the East African Oryx beisa

We carried out a population genetic analysis of five southern African gemsbok (Oryx gazella) populations based on 530 bp of the mitochondrial control region and ten microsatellites in 75 individuals. Both markers show the high variability often observed in African bovids. Three of the populations which can be traced back to very small founding or current sizes do not show any signs of reduced variability compared to the remaining populations. The mitochondrial haplotypes form three distinct lineages which most likely originated in the Pleistocene when climate fluctuations led to periodical reduction and spreading of gemsbok habitat and which, today, are found throughout the distribution range. Bayesian microsatellite analyses yielded two groups, suggesting a more recent geographical differentiation following the admixture of the mtDNA lineages. Combining our sequences with available published data of the remaining oryx species allowed for a direct molecular comparison of O. gazella and O. beisa which have sometimes been considered a single species. The average genetic divergence between haplotypes from the two taxa was very high (39.9%), supporting their classification into two different species.     

Relationship between saccharifying capacity and isolation sources for strains of the Rhizopus arrhizus complex

To discover the differences and modes of saccharifying ability among Rhizopus arrhizus strains isolated from various habitats, we grew strains in glutinous rice media to monitor the production of glucose from starch using spectrophotometry at regular time intervals. The saccharifying capacity of R. arrhizus var. delemar was found to be weaker than that of var. arrhizus and var. tonkinensis. These data provide additional phenotypic support for recognization of this genetically distinct lineage (var. delemar) as a separate species. Clinical isolates were generally low in saccharifying abilities, while all strains from southwest China had an excellent diastatic power.     

Effects of a microsporidium from the convergent lady beetle, Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae), on three non-target coccinellids

A microsporidium from Hippodamia convergens was transmitted horizontally to three non-target coccinellid hosts (Adalia bipunctata L., Coccinella septempunctata L. and Harmonia axyridis Pallas) under laboratory conditions. For all species examined, microsporidia-infected larvae took significantly longer to develop than did uninfected larvae but the microsporidium had no effect on larval mortality. Adult sex ratios of uninfected and microsporidia-infected adults were about 1:1 (♀:♂) and did not differ significantly. At the end of a 90-day trial, microsporidia-infected H. convergens produced significantly fewer eggs and did not live as long as uninfected individuals. Differences in fecundity and longevity were not observed for the three non-target coccinellids that were examined. Mean spore counts from smear preparations of microsporidia-infected A. bipunctata did not differ significantly from H. convergens, suggesting that A. bipunctata (a native coccinellid) is a suitable host for the microsporidium but infection was lighter in C. septempunctata and H. axyridis (introduced species). Vertical transmission of the pathogen was observed during the 90-day trial by examining eggs and larvae that were produced by microsporidia-infected adults. For all species examined, 100% vertical transmission of the pathogen was eventually observed. Three eugregarines were found in two adult A. bipunctata: Gregarine A trophozoites are similar in size to those of Gregarina katherina Watson (described earlier from Coccinella spp.), Gregarine B trophozoites are similar in size to those of Gregarine A but are morphology distinct, and Gregarine C trophozoites are similar in size to G. barbarara Watson (described earlier from A. bipunctata).     

Phylogeography of Pinus subsection Australes in the Caribbean Basin

Background and Aims

Four species of Pinus subsection Australes occur in the Caribbean Basin: P. caribaea, P. cubensis, P. maestrensis and P. occidentalis. This study analyses the phylogeography of these species to assess possible colonization events from Central America to the islands and subsequent population expansions during glacial periods driven by both drier climate and larger emerged land areas.

Methods

Allele size data were obtained for plastid microsatellites for 314 individuals from 24 populations, covering the distribution range of subsection Australes in the Caribbean Basin.

Key Results

In total, 113 plastid haplotypes were identified. The highest genetic diversity was found in populations of P. caribaea. Overall, Caribbean Basin populations fit the isolation by distance model. Significant phylogeographical structure was found (R_ST = 0·671 > permuted R_ST = 0·101; P < 0·0001). The haplotype network and a Bayesian analysis of population structure (BAPS) indicated different Central American origins for P. caribaea var. bahamensis and P. caribaea var. caribaea plastids, with Central America populations in northern and south-eastern groups. Sudden expansion times for BAPS clusters were close to three glacial maxima.

Conclusions

Central America contains ancestral plastid haplotypes. Population expansion has played a major role in the distribution of genetic diversity in P. caribaea var. hondurensis. Two colonization events gave rise to the P. caribaea var. bahamensis and P. caribaea var. caribaea lineages. Plastid variation in the eastern species (P. cubensis, P. maestrensis and P. occidentalis) evolved independently from that in P. caribaea var. caribaea. Incomplete lineage sorting between P. cubensis and P. maestrensis is apparent. Inferred expansion times for P. caribaea var. bahamensis and for the eastern lineages correspond to glacial maxima, whereas those for P. caribaea var. hondurensis correspond to the beginning of the temperature decrease that led to Marine Isotope Stage 8.     

Two overlooked species of Guzmania (Bromeliaceae) of the species-complex Massangea from Central America

Two new speciesGuzmania herrerae andG. scandens, that have been mistakenly identified asG. dissitiflora are described and illustrated. All three taxa belong to a natural complex of species that corresponds to the formerly recognized segregate genusMassangea E. Morren. However, without additional morphological and molecular evidence we believe it is premature to recognize this species complex as a genus separate fromGuzmania.