Fourteen samples of the Valga-10 drill core, south Estonia, from the lower Jelgava Formation (middle Pirgu Regional Stage, Upper Katian) to the lowermost Õhne Formation (lowermost Juuru Regional Stage, Lower Rhuddanian) were investigated for acritarchs. The section is biostratigraphically and chemostratigraphically well constrained; it comprises the rugata, taugourdeaui and scabra chitinozoan zones, the ordovicicus and giradeauensis conodont zones and the Hirnantian Isotopic Carbon Excursion (HICE). The good preservation allowed the identification of three prasinophyte phycomata and 52 acritarch species including the four new species Evittia porkuniensis, Helosphaeridium tongiorgii, Nexosarium leherissei and ?Veryhachium bulliferum. One new combination is proposed: Poikilofusa obliquipunctata (Uutela & Tynni 1991) comb. nov. Comparison with contemporaneaous palynofloras shows that eastern Laurentia and Baltica share a high number of species during the latest Katian—Hirnantian. Some of these species show a potential for future improvement of biostratigraphical correlation between the uppermost Katian— Hirnantian strata of low to mid-latitude carbonate platforms in eastern Laurentia and Baltica. Conversely, significant taxonomic differences exist between the assemblage studied and typical Gondwanan palynofloras. These results suggest that the Laurentian/Baltic and Gonwanan phytoplanktonic palaeoprovinces existed during latest Ordovician times. Published data reveal similar distribution pattern for chitinozoans and graptolites during the Hirnantian. A bathymetric ridge rise associated with the opening of the Rheic Ocean, coupled with the Hirnantian glacially-driven sea-level fall might have prevented water mass exchange and mixing/migration of phytoplankton between Gondwana and Laurentia/Baltica, thus being at the origin of the observed acritarch bioprovincialism. Additionally, distribution and diversity patterns of acritarchs are compared to those of other microfossils in the Valga-10 section. Near the base of the Hirnantian (Porkuni Regional Stage), benthic organisms (ostracods and scolecodonts) and phytoplankton (acritarchs) show increasing diversity with appearances of new taxa and new morphologies. Planktonic (chitinozoans) and nektonic (conodonts) organisms show a different pattern, with a decline in diversity during the earliest Hirnantian and a marked increase in the later part of the stage. Two alternative hyptotheses are proposed to explain these differences in diversification patterns: (1) the development of a shallower, proximal environment in the locality studied during the Hirnantian glaciation may have been more favourable to the diversification of benthonic organisms; (2) the planktonic and nektonic organisms suffered the effects of glaciation more than benthonic ones.

Hydrocarbon exploration in the Llanos Foothills of Colombia has intensified during the past several decades. Exploration in this region is problematic owing to structural complexities, rapid lateral facies changes, and the difficulties of acquiring good seismic imaging. These elements increase the uncertainties about the prognosis and subsequent drilling of exploratory wells. Under these conditions, biostratigraphy can play a significant role in the exploratory process. In the Llanos Foothills, palynology is the most useful biostratigraphic tool because pollen is the most abundant fossil group. In this study we analyze pollen information from 70 sections (624,744 palynomorph grains from 6707 samples) to construct a biostratigraphic zonation for the Llanos Foothills and Llanos basins. Using both graphic correlation and constrained optimization in our analysis, we propose 18 palynological zones for the Cenozoic of the Llanos and Llanos Foothills. These zones are tied to the geological timescale using 18 calibration points that include carbon isotopes, foraminifera, and magnetostratigraphy.

Honey bees (Apis mellifera L.) collect pollen for brood and young worker development, and pollinate many crops and economically important plants. Pollen was collected from honey bees from six feral honey bee colonies in southern Texas during two time periods to evaluate diurnal patterns of pollen collection. Overall, the same pollen types tended to be collected throughout the day, however, the percentages differed depending upon the time of day. Honey bees from four of the six colonies collected predominant pollen types (> 45% of a sample). Honey bees from the two colonies which did not collect a predominant pollen type collected two or more secondary pollen types (1645% of a sample). Lamiaceae was the most prevalent pollen type collected during the early sampling period and an unknown tricolporate grain was the most collected pollen type during the late sampling period. However, honey bees from one colony primarily collected the unknown tricolporate grain during both sampling periods. Several factors probably contributed to these diurnal variations in pollen collection patterns. These include floral patterns of pollen availability, resource depletion and/or profitability, nutritional needs of honey bees and preferences of individual honey bee foragers.

Pollen grains from 16 species of Vernonanthura H. Rob. were studied. All the species exhibit the type ‘A’ pollen characteristic of the genus. These grains are spheroidal to prolate—spheroidal, subechinolophate, tricolporate, with a continuous tectum which is densely microperforate, exhibiting lophae surrounding irregular depressions and having prominent spines. Despite most of the species having a similar pollen type, some taxa can be recognised by the morphology of the spines. According to the spine index (length/width), the species analysed can be divided into three groups having respectively short, medium and long spines. In addition to the size of the spines, some taxa can be distinguished by spine shape. Vernonanthura pinguis (Griseb.) H. Rob. has spines which are constricted at the base, while V. oligactoides (Less.) H. Rob. exhibits small conical spines. Vernonanthura nudiflora (Less.) H. Rob. and V. schulziana (Cabrera) H. Rob. have spines with rounded apices. This study confirms that Vernonanthura is a well-defined group based on pollen characteristics and that pollen morphology is a significant feature in the characterisation of species and genera of Vernonieae.

Early Cambrian acritarchs from the Lükati Formation of Estonia are described, based on new material, and their biological affinities reviewed. The phenotypical variants and the inferred function of their vesicles are indicative for recognising zygotic/resting cysts and vegetative cells. They represent the Chlorophytes in the class Prasinophyceae, which reproduce asexually (forming resting phycoma cysts), and Chlorophyceae, which reproduce sexually (zygotic cysts). Some species had a complex life cycle, with alternating vegetative and reproductive generations that differed morphologically. Based on acritarch records from the Baltica palaeocontinent, of which the Lükati Formation assemblage is a part, and the global PhytoPal Taxonomic Database (PhytoPal Project, Leverhulme Trust, Leicester University, 2003–2006), the early Cambrian diversification of phytoplankton is reviewed. The initial Cambrian diversification, and a recovery after the end-Ediacaran extinction, was rapid and exhibited a stepwise pattern of radiation episodes covering short intervals equivalent to biochrons lasting a few million years, estimated from the numerical ages of the strata containing them and the current time scale of the early Cambrian. However, the first appearance datum (FAD) of new species within the biozones/biochrons appears in a succession rather than at one stratigraphical level, indicating true biological speciations. The only genera surviving from the Proterozoic Eon are Leiosphaeridia, Tasmanites, Pterospermella and Pterospermopsimorpha; these are Lazarus genera radiating new species in the early Cambrian. All other Cambrian genera and species are new, morphologically innovative, and much smaller.

Small forest hollows represent a specialised site type for pollen analysis, since they mainly record the vegetation within an approximate radius of 20–100 m from the hollow. We discuss how to choose the most appropriate small forest hollow for pollen analysis. Hollow size, site topography, location, sediment type, drainage aspects and disturbance characteristics of the specific hollows should be considered during site selection. Guidelines are developed on how to take the core and outline the special characteristics of small hollow palynology that influence data interpretation.