This is an overview of the of the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Messel Formation The Messel Formation is a geologic formation in Hesse, central Germany, dating back to the Eocene epoch (about 47 Ma). Its geographic range is restricted to the Messel pit. There it unconformably overlies crystalline Variscan basement and ...

as explored by the

Messel Pit The Messel Formation is a Formation (geology), geologic formation in Hesse, central Germany, dating back to the Eocene Epoch (geology), epoch (about 47 Ma). Its geographic range is restricted to the Messel pit. There it unconformably overlie ...

excavations in Germany. A former

quarry A quarry is a type of open-pit mining, open-pit mine in which dimension stone, rock (geology), rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some juri ...

and now UNESCO

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

, the Messel Formation preserves what lived in and around a

meromictic A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters. The term ''meromictic'' was coined by the Austria ...

lake surrounded by a paratropical rainforest during the latest early to earliest middle Eocene, approximately 47 Ma. A complete list of plant taxa was published in 2024. Several major monographs on the paleoflora have been published since the early 1900s, with producing the first leaf monograph in 1922, followed by Heidemarie Thiele-Pfeiffer in 1988 who provided the first in-depth

palynological Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

revision and expansion. Margaret Collinson, Steven Manchester, and Volker Wilde collaborated to study and redescribe the flowers, fruits, seeds, and other reproductive organs of the formation, with the monograph being published in 2011. Most recently, Johannes Bouchal, Christian Geier, Friđgeir Grímsson and colleagues have completed monographic studies of the

palynomorphs Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

, combining traditional

light microscopy Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical, el ...

with

scanning electron microscopy A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that ...

to achieve greater phylogenetic precision.

Dinoflagellates

Only a single dinoflagellate taxon has been described formally from the Messel formation. Based on the predominance in layers where heavy nearshore runoff or slippage is present, its suggested ''Messelodinium thielepfeifferae'' was likely an inhabitant of warm nearshore waters in the adult stage or wind and wave action resulted in large accumulation of the cysts. ''M. thielepfeifferae'' populations are most prevalent in the older layers of the lake, when it was suggested to be

holomictic Holomictic lakes are lakes that have a uniform temperature and density from surface to bottom at a specific time during the year, which allows the lake waters to mix in the absence of stratification. Details Holomictic lakes mix at least occa ...

and become absent in the youngest layers when green algae become dominant with the lake shifting to

conditions and the water chemistry changed.

Charophyta

Olaf Lenz ''et al'' (2011) briefly noted the presence of the

Zygnemataceae The Zygnemataceae are a family of Algae#Morphology, filamentous or unicellular, uniseriate (unbranched) green algae. The filaments are septum, septated and reproduction is by Sexual conjugation, conjugation; ''Spirogyra'' is commonly used in scho ...

fossil genus ''Ovoidites'', but only gave general population densities with no enumeration on species information.

Chlorophyta

Several

chlorophyte Chlorophyta is a division (botany), division of green algae informally called chlorophytes. Description Chlorophytes are eukaryotic organisms composed of cells with a variety of coverings or walls, and usually a single green chloroplast in ea ...

green algae are identified from the Messel Formation, with the greatest concentrations being found in the youngest layers. In the older layers ''Tetraedron minimum'' is a distinct component of the yearly varves in the lake, with large blooms occurring to form the lighter summer portions of the varve couplets. In the younger layers, ''Botryococcus'' species become the most prolific, having taken over as a major phytoplankton taxon from ''T. minimum'' and the dinoflagellate ''Messelodinium thielepfeifferae''.

Pteridophytes

Conifers

Basal angiosperms

Nymphaeales

Magnoliids

Laurales

Magnoliales

Monocots

Alismatales

Arecales

Liliales

Pandanales

Poales

Basal eudicots

Proteales

Ranunculales

Superasterids

Campanulids

Cornales

Ericales

Lamiids

Superrosids

Fabids

Malvids

Myrtales

Saxifragales

Vitaceae

''Incertae sedis''

'' Carpolitus'' is a plant

morphogenus Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...

circumscribed for fossil fruits and seeds that are distinct but not identifiable to defined taxa. Collinson, Manchester, & Wilde (2012) described but did not name 63 distinct ''Carpolithus'' morphotypes from the Messel Formation.

Pollen and spores

The first foray into Messel

palynology Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

was produced by H. D. Pflug (1952) with follow-up papers in 1957 and coauthored with P. Thomas in 1953. The pollen and spore record was revised and expanded by Heidemarie Thiele-Pfeiffer (1988) who provided the largest in depth palynological work focusing exclusively on the Messel Formation.

Dinoflagellates

Charophyta

Chlorophyta

Pteridophytes

Conifers

Basal angiosperms

Nymphaeales

Magnoliids

Laurales

Magnoliales

Monocots

Alismatales

Arecales

Liliales

Pandanales

Poales

Basal eudicots

Proteales

Ranunculales

Superasterids

Campanulids

Cornales

Ericales

Lamiids

Superrosids

Fabids

Malvids

Myrtales

Saxifragales

Vitaceae

''Incertae sedis''

Pollen and spores

Pteridophyte spores

Lycophyte spores

Conifer pollens

Basal angiosperm pollens

Chloranthalean pollens

Magnoliid pollens

Monocot pollens

Alismatalean pollens

Arecalean pollens

Commelinid pollens

Superasterid pollens

Campanulid pollens

Cornalean pollens

Ericalean pollens

Lamiid pollens

Santalalean pollens

Superrosid pollens

Fabid pollens

Malvid pollens

Myrtalean pollens

''Incertae sedis'' pollens

References