''Paradinandra suecica'' is a species of fossil plants from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

of Sweden. It is of uncertain placement within the order

Ericales The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for tea, persimmon, blueberry, kiwifruit, Brazil nuts, argan, and azalea. The order includes trees, bushes, lia ...

, and was described in 2001.

Biostratigraphy

The specimens of ''Paradinandra'' had been naturally fusanised (turned into charcoal), and were recovered by sieving sand and clay. The deposits are thought to be of Late

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. ...

to Early

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

age, and are located in a former

kaolin Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral ...

quarry A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envir ...

owned by

Höganäs AB Höganäs AB is a Swedish multinational based in Höganäs. It is the world's largest producer of powdered metals. It develops and markets powders for customers in metallurgical industries. The company's portfolio of products and services includ ...

near Näsum, Skåne, Sweden (). The specimens were described by Jürg Schöneberger and

Else Marie Friis Else Marie Friis (born 18 June 1947) is a Danish botanist and paleontologist. She is Professor Emerita in the Department of Geoscience at Aarhus University. Her work has been fundamental in the phylogenetic analysis of angiosperms, with widespr ...

in 2001 in the ''

American Journal of Botany The ''American Journal of Botany'' is a monthly peer-reviewed scientific journal which covers all aspects of plant biology. It has been published by the Botanical Society of America since 1914. The journal has an impact factor of 3.038, as of 2019 ...

'', and have been deposited at the Swedish Museum of Natural History.

Description

The flowers of ''P. suecica'' are less than long, which is typical for fossil flowers from the Cretaceous. The flowers are organised into

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

of five parts. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s are free,

lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

, and have as obtuse tip. They bear

trichome Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a p ...

s along the median

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenat ...

, and become much thinner away from the thickened centre. The petals are thought to be fused together, at least at their bases; they are shaped like a bishop's mitre. Each flower has 15 stamens, which may also be united at the base, and taper towards the attachment of the anther. The filaments of the outer whorl of five stamens are long, while those of the inner whorl are around either or long. This results in the anthers falling into three distinct layers in the

bud In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...

. It is not known whether the difference is retained on

flowering A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

Pollen grain Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

s found associated with the flowers are long, and appear to be tricolpate, which is a characteristic of the

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots ...

. The

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils' ...

bears three styles, and the ovules are curved.

Affinities

In their original

description Description is the pattern of narrative development that aims to make vivid a place, object, character, or group. Description is one of four rhetorical modes (also known as ''modes of discourse''), along with exposition, argumentation, and narra ...

, Schöneberger and Friis noted that the flowers had few features which would allow them to determine the relationships of ''Paradinandra'' to other plants. The stamen arrangement seen in ''Paradinandra'' and the curved ovules are both seen in various families within the

(''

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

''), and some families, such as Ternstroemiaceae, show both. This suggests that closest relatives of ''Paradinandra'' are found among the order Ericales, but the authors could not assign the fossil to any single family, and therefore assigned it ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

'' (of uncertain placement) within the order.

Biostratigraphy

Description

Affinities

References

Further reading