The Messel Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Hesse Hesse or Hessen ( ), officially the State of Hesse (), is a States of Germany, state in Germany. Its capital city is Wiesbaden, and the largest urban area is Frankfurt, which is also the country's principal financial centre. Two other major hist ...

, central

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, dating back to 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 ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

(about 47 Ma). Its geographic range is restricted to 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 ...

. There it

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

overlies crystalline

Variscan The Variscan orogeny, or Hercynian orogeny, was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan ...

basement and its

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

cover (

Rotliegend The Rotliegend, Rotliegend Group or Rotliegendes () is a lithostratigraphic unit (a sequence of rock strata) of latest Carboniferous to Guadalupian (middle Permian) age that is found in the subsurface of large areas in western and central Europe ...

) as well as Eocene volcanic breccias derived from the basement rocks. The formation mainly comprises

lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

laminated bituminous shale (‘

oil shale Oil shale is an organic-rich Granularity, fine-grained sedimentary rock containing kerogen (a solid mixture of Organic compound, organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general compos ...

’) renowned for its content of

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

in exceptional preservation, particularly plants, arthropods and vertebrates (e.g. ''

Darwinius masillae ''Darwinius'' is a genus within the infraorder Adapiformes, a group of basal strepsirrhine primates from the middle Eocene epoch. Its only known species, ''Darwinius masillae'', lived approximately 47 million years ago (Lutetian stage) based on ...

'').

Messel pit

The Messel pit () is a disused

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 ...

near the village of

Messel Messel is a municipality in the district of Darmstadt-Dieburg in Hesse near Frankfurt am Main in Germany. The village is first mentioned, as ''Masilla'', in the Lorsch codex. Messel was the property of the lords of Groschlag from ca. 1400 to 1799 ...

(

Landkreis Darmstadt-Dieburg Darmstadt-Dieburg is a Kreis (district) in the south of Hesse, Germany. Neighboring districts are Offenbach, Aschaffenburg, Miltenberg, Odenwaldkreis, Bergstraße, Groß-Gerau, and the district-free city of Darmstadt, which it surrounds. Hist ...

, Hesse) about southeast of

Frankfurt am Main Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...

, Germany. Bituminous shale was mined there. Because of its abundance of well-preserved

of the Messel Formation dating from the middle of the

, it has significant geological and scientific importance. Over 1400

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

of plants, fungi and animals have been documented at the site. After almost becoming a landfill, strong local resistance eventually stopped these plans and the Messel pit was declared a

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 ...

on 9 December 1995. Significant scientific discoveries about the early evolution of mammals and birds are still being made at the Messel Pit, and the site has increasingly become a tourist site as well.

History

Brown coal Lignite (derived from Latin ''lignum'' meaning 'wood'), often referred to as brown coal, is a soft, brown, Combustion, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% and is considered ...

and later

was actively mined from 1859. The pit first became known for its wealth of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s around 1900, but serious scientific excavation only started around the 1970s, when falling oil prices made mining the quarry uneconomical. Commercial oil shale mining ceased in 1971 and a cement factory built in the quarry failed the following year. The land was slotted for use as a

landfill A landfill is a site for the disposal of waste materials. It is the oldest and most common form of waste disposal, although the systematic burial of waste with daily, intermediate and final covers only began in the 1940s. In the past, waste was ...

, but the plans came to nought and the Hessian state bought the site in 1991 to secure scientific access. In the few years between the end of mining and 1974, when the state began preparing the site for garbage disposal, amateur collectors were allowed to collect fossils. The amateurs developed the " transfer technique" that enabled them to preserve the fine details of small fossils, the method still employed in preserving the fossils today. Many of the known specimens from the site have come from amateur collectors and in 1996, an amnesty on previously collected fossils was put in effect, in the hope of getting privately owned collections back into public ownership and available to science.

Depositional characteristics

The current surface of the Messel pit is roughly below the local land and is about in area. The oil-shale bed originally extended to a depth of . 47 million years ago in the

when the Messel deposits formed, the area was 10° further south than it is now. The period was very close to the Early Eocene Climatic Optimum and the climate and ecology of the site were very different, characterised by a mean annual temperature of 22 °C and a large series of

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

lakes surrounded by lush sub-tropical forests that supported an incredible diversity of life. The Messel lake bed was probably a center point for drainage from nearby rivers and creeks. Kopidodon Senckenberg 2007-01

The pit deposits were formed during the

Epoch of the

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

Period about 47 million years ago, based on dating of basalt fragments underlying fossilbearing strata.

Oil shale Oil shale is an organic-rich Granularity, fine-grained sedimentary rock containing kerogen (a solid mixture of Organic compound, organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general compos ...

, formed by the slow anoxic deposition of mud and dead vegetation on the lake bed, is the primary rock at the site. Its sediments extend downward and lie atop an older

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

foundation. The fossils within the shale show a remarkable clarity and preservation due to the unique depositional characteristics of the lake and so the Messel pit represents a Konservat-Lagerstätte. The upper stratifications of the lake most certainly supported a variety of organisms, but the bottom was subject to little disturbance by current, spawning a very anoxic environment. This prevented many epifaunal and infaunal species from inhabiting this niche and thus bioturbation was kept at a minimum. Overturn of the lake layers (caused by seasonal variations) lowered oxygen content near the surface and led to a periodic "die-off" of aquatic species. Combined with a relatively low rate of deposition, per year, this provided a prime environment for the preservation of fauna and flora.

Volcanic gas releases

The area around the Messel Pit is believed to have been geologically and tectonically active during the Eocene. Some scientists, especially Jens Franzen, have hypothesized that events much like the 1986

volcanic gas Volcanic gases are gases given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities (Vesicular texture, vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating from ...

releases at

Lake Nyos Lake Nyos ( ) is a crater lake in the Northwest Region of Cameroon, located about northwest of Yaoundé, the capital. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcan ...

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

, could account for the deaths and preservation in the lake of non-aquatic species. Periodic subsurface shifts possibly released large concentrations of toxic gases (such as carbon dioxide and hydrogen sulfide) into the lake and adjoining ecosystems, killing susceptible organisms. During these releases, birds and bats might have fallen in if near the lake surface and terrestrials could be overwhelmed when near the lake shore. Other scientists, especially Wighart von Koenigswald, have hypothesized that cyanobacterial blooms could account for the rich faunal assemblage of Messel, with animals succumbing after drinking water contaminated with cyanobacterial toxins. This hypothesis drew support from the occurrence of gravid and or copulating animals at Messel, which supposedly reflect a dominant season of death. Others explored the null hypothesis of accidental death. In particular, Krister T. Smith and colleagues found that the annual number of fossilized bats in Messel is comparable to the number of bats that drown in modern swimming pools. That is, bat mortality is not actually elevated at Messel, which fails to support the "mass mortality" hypotheses above. Regardless of the manner of death, the exceptional preservation at Messel (e.g., mostly complete skeletons) indicates that the lake was very deep. Animals that fell in it drifted downwards into oxygen-poor water without scavengers, where they were overlaid by successive layers of mud that petrified later, thus producing an aggregation of fossils of exceptional quality, quantity, integrity, and variety.

Access

Exhibits from the pit may be seen in the

town, the fossil Museum in Messel, the

Hessisches Landesmuseum Hessisches Landesmuseum Darmstadt (HLMD) is a large multidisciplinary museum in Darmstadt, Germany. The museum exhibits Rembrandt, Beuys, a primeval horse and a mastodon under the slogan "The whole world under one roof". As one of the oldest publ ...

Darmstadt Darmstadt () is a city in the States of Germany, state of Hesse in Germany, located in the southern part of the Frankfurt Rhine Main Area, Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it the ...

( from Messel) and also the Senckenberg Museum in

(some from Messel). Casual visitors can park close to the pit and walk around to a viewing platform overlooking the pit. Entrance to the pit is only possible as part of a specially organized tour.

Fossils

The Messel Pit provides the best preserved evidence of

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

flora and fauna so far discovered, with over 1400 taxa identified. Most other sites are lucky to contain partial

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

s, but Messel boasts extensive preservation of structural integrity, even going so far as to preserve the fur, feathers and "skin shadows" of some species. Unusual preservation has sparked some closely reasoned interpretations. The symptomatic "dumb-bell"-shaped bite marks on either side of the leaf vein on a fossilised leaf have been identified as the death-grip of a

carpenter ant Carpenter ants (''Camponotus'' spp.) are a genus of large ants (workers ) indigenous to many parts of the world. True carpenter ants build nests inside wood, consisting of galleries chewed out with their mandibles or jaws, preferably in dead, ...

terminally parasitized by the fungus ''

Ophiocordyceps unilateralis ''Ophiocordyceps unilateralis'', commonly known as zombie-ant fungus, is an entomopathogenic fungus, insect-pathogenic fungus, discovered by the British naturalist Alfred Russel Wallace in 1859. Zombie ants, infected by the ''Ophiocordyceps unila ...

'', that, apparently then as today, commandeered its behavior, in order to release its spores from a favourable location; it is the earliest concrete sample of fungal behavioural manipulation. The diversity of species is remarkable partly as a result of the hypothesized periodic gas releases. A brief summary of some of the fossils found at the site follows: * Nine mating pairs of fossil turtles have been found. The turtles, '' Allaeochelys crassesculpta'', were ''in coitus'' (in the act of having sex). They are male-female pairs, with the male's tail tucked under the female, which is how they copulate. Their death must have been rapid. It is supposed that the turtles had started mating in the aerated surface waters of the ancient lake. As they sank into deeper water, they were overcome by the release of

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

volcanic gas. They were then buried in the lakebed sediment. Turtles belonging to this

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

are still living. They have lost their reptilian scales, and their skin absorbs

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

from the water. Normally, this is an advantage: it helps them stay submerged for long periods. However, under

anoxic Anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of dissolved ox ...

conditions it is a disadvantage, because

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

and dissolved poisons are absorbed as well. * Over 10,000 fossilized fish of numerous species * Thousands of aquatic and terrestrial insects, some with distinct coloration still preserved * Innumerable small mammals including pygmy horses, large mice, primates, ground dwellers (

hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are 17 species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. The ...

marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...

pangolin Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (). The one extant family, the Manidae, has three genera: '' Manis'', '' Phataginus'', and '' Smutsia''. ''Manis'' comprises four species found in Asia, while ' ...

s),

aardvark Aardvarks ( ; ''Orycteropus afer'') are medium-sized, burrowing, nocturnal mammals native to Africa. Aardvarks are the only living species of the family Orycteropodidae and the order Tubulidentata. They have a long proboscis, similar to a pi ...

relatives and bats. The fossilized bat specimens have provided insights into the evolution of echolocation. * Large numbers of birds, particularly predatory species. * Crocodiles, frogs, turtles,

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s and other reptiles or amphibians * Remains of over 30 distinct plant species, including palm leaves, fruits, pollen, wood,

walnut A walnut is the edible seed of any tree of the genus '' Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. They are accessory fruit because the outer covering of the fruit is technically an i ...

s and

grapevine ''Vitis'' (grapevine) is a genus of 81 accepted species of vining plants in the flowering plant family Vitaceae. The genus consists of species predominantly from the Northern Hemisphere. It is economically important as the source of grapes, bot ...

s The following is only a partial list: Darwinius masillae PMO 214

Mammals

:''

'', identified in 2009 as an adapiform primate :'' Kopidodon'', an extinct arboreal

cimolesta Cimolesta is an extinct order of non-placental eutherian mammals. Cimolestans had a wide variety of body shapes, dentition and lifestyles, though the majority of them were small to medium-sized general mammals that bore superficial resemblances t ...

n :''

Leptictidium ''Leptictidium'' is an extinct genus of small mammals that were likely bipedal. Comprising eight species, they resembled today's bilbies, bandicoots, and elephant shrews, and occupied a similar niche. They are especially interesting for their c ...

'', an extinct omnivorous hopping mammal (of the leptictid family) :'' Propalaeotherium'', an early relative of horses :'' Ailuravus'', a

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

:''

Peradectes ''Peradectes'' is an extinct genus of small metatherian mammals known from the latest CretaceousKorth, W. W. (2008). Marsupialia. In C. M. Janis, G. F. Gunnell, & M. D. Uhen (Eds.)Evolution of Tertiary Mammals of North America: Volume 2, Small Mam ...

'', a

metatherian Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...

:''

Palaeochiropteryx ''Palaeochiropteryx'' ( ) is an extinct genus of bat from the Lutetian, Middle Eocene of Europe and North America. It contains three very similar species – ''Palaeochiropteryx tupaiodon'' and ''Palaeochiropteryx spiegeli'', both from the famous ...

'', an early

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

:'' Lesmesodon'', a small hyaenodontid :'' Eomanis'', an early

:'' Eurotamandua'', a scaleless,

anteater Anteaters are the four extant mammal species in the suborder Vermilingua (meaning "worm tongue"), commonly known for eating ants and termites. The individual species have other names in English and other languages. Together with sloths, they ar ...

-like pangolin :'' Europolemur'', a primate :''

Hyrachyus ''Hyrachyus'' (from ''Hyrax'' and "pig") is an extinct genus of perissodactyl mammal that lived in Eocene Europe, North America, and Asia. Its remains have also been found in Jamaica. It is closely related to ''Lophiodon''.Hayden, F.V''Report of ...

'', ancestor of rhinoceroses :''

Paroodectes ''Paroodectes'' ("near '' Oodectes''") is an extinct genus of placental mammals from clade Carnivoraformes, that lived in Europe during the middle Eocene.Robert L. Carroll (1988."Vertebrate Paleontology and Evolution."W. H. Freeman and Company, ...

'', an early carnivorous mammal :'' Messelogale'', an early carnivorous mammal :''

Pholidocercus ''Pholidocercus'' is an extinct monotypic genus of mammal from the Messel pit related to and resembling the modern-day hedgehog with a single species, ''Pholidocercus hassiacus''. Like the hedgehog, it was covered in thin spines. Unlike hedgeh ...

'', an early

:'' Macrocranion'', an early long-tailed

:''

Masillamys ''Masillamys'' is an extinct genus of rodent. It was named in 1954 by Tobien based on fossils found in the Quercy Phosphorites Formation The Quercy Phosphorites Formation (French language, French: ''Phosphorites du Quercy''; ) is a Formation ...

'', an early

:''

Messelobunodon ''Messelobunodon'' is an extinct genus of early even-toed ungulate Artiodactyls are placental mammals belonging to the order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five ...

'', an early

artiodactyl Artiodactyls are placental mammals belonging to the order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other t ...

:'' Godinotia'', an early primate :''

Buxolestes ''Buxolestes'' is an extinct genus of semi-aquatic, non-placental eutherian mammals belonging to the family Pantolestidae. Species in this genus were part of the first placental evolutionary radiation during the Middle Eocene (48-40 mya) and found ...

'', a semiaquatic,

otter Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among ...

-like cimolestan :''

Hassianycteris ''Hassianycteris'' is an extinct genus of Early Eocene (Ypresian) to Middle Eocene (Lutetian) bats from the Hassianycterididae with four or five known species: the type (''H. messelensis''), ''H. magna'', and ''H. revilliodi'', all found in the ...

'', an early bat :'' Archaeonycteris'', an early bat :'' Tachypteron'', a possible emballonurid or miniopterid bat

Birds

:''

Palaeotis ''Palaeotis'' is a genus of paleognath birds from the middle Eocene epoch of central Europe. One species is known, ''Palaeotis weigelti''. The holotype specimen is a fossil tarsometatarsus and phalanx. Lambrect (1928) described it as an extin ...

'', an early struthionid :'' Strigogyps sapea'' (formerly ''Aenigmavis'') a cariamiform :'' Eocoracias'', an early coraciiform with known coloration :'' Messelornis'', the Messel-bird; a species of gruiform :'' Masillastega'', a

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

sulid :'' Lapillavis'', a possible trogonid relative :'' Cypseloramphus,'' a basal apodiform :The

Messelasturidae Messelasturidae is an extinct family of birds known from the Eocene of North America and Europe. Their morphology is a mosaic that in some aspects are very similar to modern hawks and falcons, but in others are more similar to parrots. Initially ...

(''

Messelastur ''Messelastur'' is a genus of messelasturid bird. It is known from the Messel pit of Germany, which dates to the Eocene.Peters, D.S. (1994) ''Messelastur gratulator'' n. gen. n. spec., ein Greifvogel as der Grube Messel (Aves: Accipitridae). ''C ...

'' and ''

Tynskya ''Tynskya'' is an extinct genus of messelasturid bird. Distribution ''T. eocaena'', the type species, is known from fossils found in the North American Green River Formation. The Walton Member of the London Clay Formation of England contai ...

''), carnivorous relatives of modern parrots :'' Palaeoglaux'', an early owl with enigmatic breast feathers :''

Paraprefica ''Paraprefica'' is an extinct genus of potoo (family Potoo, Nyctibiidae) from the middle Eocene (c. 48 million years ago). Its fossil remains have been found in the Messel pit at Messel, Germany. Taxonomy It is the only known member of the ext ...

'', an early

potoo Potoos (family (biology), family Nyctibiidae) are a group of birds related to the nightjars and frogmouths. They are sometimes called poor-me-ones, after their haunting bird vocalization, calls. The family Nyctibiidae was formerly included with ...

:'' Paraortygoides'', a galliform :''

Masillaraptor ''Masillaraptor'' is an extinct genus of masillaraptorid, a group of primitive falconiforms, from the Middle Eocene Messel Pit, Germany. It is a long-legged relative of the living falcons. Known species Only one species of ''Masillaraptor'' ...

'', an early

falconiform The falcons and caracaras are around 65 species of diurnal birds of prey that make up the family Falconidae (representing all extant species in the order Falconiformes). The family likely originated in South America during the Paleocene and is d ...

:'' Parargornis'', an early apodiform :''

Messelirrisor The extinct ''Messelirrisor'' is a genus of Bucerotiformes, the sole representative of the family Messelirrisoridae. They were tiny hoopoe-like birds that were the earliest representatives of the hoopoe/ wood-hoopoe lineage, and they were among ...

'', a tiny bucerotiform closely related to

hoopoe Hoopoes () are colourful birds found across Africa, Asia, and Europe, notable for their distinctive "Crest (feathers), crown" of feathers which can be raised or lowered at will. Two living and one extinct species are recognized, though for many y ...

s and

wood-hoopoe The wood hoopoes or scimitarbills are a small African family, Phoeniculidae, of near passerine birds. They live south of the Sahara Desert and are not bird migration, migratory. While the family is now restricted to Sub-Saharan Africa, fossil evi ...

s :'' Selmes'' (an

anagram An anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. For example, the word ''anagram'' itself can be rearranged into the phrase "nag a ram"; which ...

of "Messel"), a

mousebird The mousebirds are birds in the order Coliiformes. They are the sister group to the clade Cavitaves, which includes the Leptosomiformes (the cuckoo roller), Trogoniformes ( trogons), Bucerotiformes ( hornbills and hoopoes), Piciformes ( wo ...

with stubby toes :'' Gastornis'' (formerly ''Diatryma''), a large, flightless galloansere :'' Hassiavis'',Mayr, G.. (2004). New specimens of Hassiavis laticauda (Aves: Cypselomorphae) and Quasisyndactylus longibrachis (Aves: Alcediniformes) from the Middle Eocene of Messel, Germany. CFS Courier Forschungsinstitut Senckenberg. 252. 23-28.
/ref> a member of

Cypselomorphae Strisores ( ), sometimes called nightbirds, is a clade of birds that includes the living family (biology), families and order (biology), orders Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Steatornithidae (oilbirds), P ...

:'' Quasisyndactylus'', a member of Alcediniformes :''

Vanolimicola ''Vanolimicola'' is an Extinction, extinct genus of bird, birds that lived during the Lutetian Stage (stratigraphy), stage of the Eocene Epoch (geology), epoch. Distribution ''Vanolimicola longihallucis'' is known from the Messel Formation of ...

'', a possible charadriiform :A currently unnamed lithornithid, a

sandpiper Scolopacidae is a large family of shorebirds, or waders, which mainly includes many species known as sandpipers, but also others such as woodcocks, curlews and snipes. Most of these species eat small invertebrates picked out of the mud or so ...

-like paleognath, the first record of its kind in Middle

Europe.

Reptiles

:''

Asiatosuchus ''Asiatosuchus'' is an extinct genus of crocodyloid crocodilians that lived in Eurasia during the Paleogene. Many Paleogene crocodilians from Europe and Asia have been attributed to ''Asiatosuchus'' since the genus was named in 1940. These speci ...

'', a large crocodile :'' Diplocynodon'', an alligator :'' Hassiacosuchus'', a

durophagous Durophagy is the eating behavior of animals that consume hard-shelled or exoskeleton-bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including fossil t ...

alligator :''

Bergisuchus ''Bergisuchus'' is an extinct genus of small sebecosuchian mesoeucrocodylian known primarily from the Eocene Messel Pit in Germany. Few fossils of ''Bergisuchus'' have been discovered, only a single incomplete snout, a few partial lower jaws and ...

'', a

sebecosuchia Sebecosuchia (meaning "Sobek crocodiles") is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group was long thought to have first appeared in the Late Cretaceous with the baurusu ...

n crocodiliform :''

Eoconstrictor ''Eoconstrictor'' is an extinct genus of Booidea, booid snake, from the Eocene of Germany (Messel Pit). The type species, ''E. fischeri'' is known from multiple well-preserved specimens found in the Messel Pit of Germany. It was originally named a ...

'', 2-m snakes related to Neotropical boas, Boinae :'' Messelophis'', a tiny, live-bearing or

viviparous In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

boa :''

Messelopython ''Messelopython'' is an extinct genus of pythonoid that lived in Germany during the Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lute ...

'', the oldest known relative of pythons :''

Cryptolacerta ''Cryptolacerta'' (Ancient Greek and Latin for "Hidden lizard" – κρυπτς or ''crypto'' meaning "hidden" and ''lacerta'' meaning "lizard") is an extinct genus of lacertoid lizard which lived during the Eocene epoch (Lutetian stage, about ...

'', a lizard with affinities to amphisbaenians :'' Geiseltaliellus'', a lizard with affinities to Corytophaninae :'' Allaeochelys crassesculpta'', aquatic turtles related to '' Carettochelys''

Fish

bowfin The ruddy bowfin (''Amia calva'') is a ray-finned fish native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being one of only two surviving species ...

, variously described as ''Amia'' (the modern genus) or '' Cyclurus'' :''

Amphiperca ''Amphiperca'' is an extinct genus of freshwater percomorph ray-finned fish that lived from the early to middle Eocene of Europe. It has one known species, ''A. multiformis'', known from the famous Messel Pit The Messel Formation is a Formati ...

'', an early

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

:''

Palaeoperca ''Palaeoperca'' is an extinct genus of prehistoric bony fish that lived from the early to middle Eocene. Fossils were found in the Messel pit The Messel Formation is a Formation (geology), geologic formation in Hesse, central Germany, dating b ...

'', another early

:''

Atractosteus ''Atractosteus'' (from Greek ''atraktos'' (ἀτρακτὀς), 'spindle' and ''osteon'' (ὀστέον), 'bone') is a genus of gars in the family Lepisosteidae, with three extant species. It is one of two surviving gar genera alongside ''Lepisost ...

'', a gar :eel

Insects

;Hemiptera *'' Wedelphus dichopteroides'' Szwedo & Wappler, 2006 ;Hymenoptera ''Family Formicidae (ants)'' *'' Casaleia eocenica'' Dlussky & Wedmann, 2012 *''

Cephalopone ''Cephalopone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe. There are two described species placed into the genus, ''Cephalopone grandis'' and ''Cephalopone potens''. ''Cephalopone'' ...

'' – ''Cephalopone grandis'' and ''Cephalopone potens'' *''

Cyrtopone ''Cyrtopone'' is an extinct genus of ants in the Formicidae, formicid subfamily Ponerinae described from fossils found in Europe. There are four described species placed into the genus, ''Cyrtopone curiosa'', ''Cyrtopone elongata'', ''Cyrtopone ...

'' – ''Cyrtopone curiosa'', ''Cyrtopone elongata'', ''Cyrtopone microcephala'', and ''Cyrtopone striata'' *'' Gesomyrmex pulcher'' Dlussky, Wappler, & Wedmann, 2009 *''

Messelepone leptogenoides ''Messelepone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe. ''M. leptogenoides'' is the only species assigned to the genus, which is one of several Lutetian Ponerinae genera. History ...