Emydidae is a family of testudines (turtles) that includes close to 50 species in 10 genera. Members of this family are commonly called terrapins, pond turtles, or marsh turtles. Several species of Asian box turtles were formerly classified in the family; however, revised taxonomy has separated them to a different family (Geoemydidae). As currently defined, the Emydidae are entirely a Western Hemisphere family, with the exception of two species of pond turtle.
The Trionychidae are a taxonomic family of a number of turtle genera, commonly known as softshell turtles. The family was erected by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can adapt to living in highly brackish areas. Members of this family occur in Africa, Asia, and North America, with extinct species known from Australia. Most species have traditionally been included in the genus Trionyx, but the vast majority have since been moved to other genera. Among these are the North American Apalone softshells that were placed in Trionyx until 1987.
Leptictidium is an extinct genus of small mammals that were likely bipedal. Comprising eight species, they resembled today's bilbies, bandicoots, and elephant shrews. They are especially interesting for their combination of characteristics typical of primitive eutherians with highly specialized adaptations, such as powerful hind legs and a long tail which aided in locomotion. They were omnivorous, their diet a combination of insects, lizards and small mammals. Lepticidium and other lepticids are not placentals, but are non-placentral eutherians, although closely related. They appeared in the Lower Eocene, a time of warm temperatures and high humidity, roughly fifty million years ago. Although they were widespread throughout Europe, they became extinct around thirty-five million years ago with no descendants, probably because they were adapted to live in forest ecosystems and were unable to adapt to the open plains of the Oligocene.
The Messel pit is a disused quarry near the village of Messel about 35 km (22 mi) southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its abundance of well-preserved fossils dating from the middle of the Eocene, it has significant geological and scientific importance. Over 1000 species of plants and animals have been found 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 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.
The pig-nosed turtle, also known as the pitted-shelled turtle or Fly River turtle, is a species of turtle native to northern Australia and southern New Guinea. It is the only living member of the family Carettochelyidae, which are related to softshell turtles.
Palaeochiropteryx is an extinct genus of bat from the Middle Eocene of Europe and North America. It contains three very similar species – Palaeochiropteryx tupaiodon and Palaeochiropteryx spiegeli, both from the famous Messel Pit of Germany, as well as Palaeochiropteryx sambuceus from the Sheep Pass Formation. They are usually found complete and exceptionally preserved, even retaining the outlines of their fur, ears, and wing membranes.
Amyda is a genus of softshell turtles in the family Trionychidae. It contains two extant species:
Cyclanorbis is a genus of softshell turtles in the family Trionychidae. The genus is endemic to Africa.
Nilssonia is a genus of softshell turtles from rivers, streams, ponds, and lakes in South Asia and Burma. In many treatments, it is monotypic, with the single species Burmese peacock softshell. However, the supposed other genus of peacock softshells, Aspideretes, is more closely related to N. formosa than had been believed. They differ only in the neural plates between the first pleural scale pair of the bony carapace, which are fused into one in N. formosa and unfused in the others.
Heterohyus is an extinct genus of apatemyid from the early to late Eocene. A small, tree-dwelling creature with elongated fore- and middle fingers, in these regards it somewhat resembled a modern-day aye-aye.
Three skeletons have been found at the early Eocene site at Messel Pit, Germany
Diplocynodon is an extinct genus of alligatoroid that lived during the Paleocene to Middle Miocene in Europe. It looked very similar to the modern caiman in that it was small and had bony armour scutes covering its neck, back, belly, and tail. The longest Diplocynodon recovered was 4 feet in length and probably fed on small fish, frogs, and took insects when young.
Hassiacosuchus is an extinct genus of small alligatorid from the early Eocene of Germany, found at the Messel pit. It was named in 1935 by K. Weitzel, and the type species is H. haupti. A second species, H. kayi, was named in 1941 by C.C. Mook for material from the Bridgerian of Wyoming, but was reassigned to Procaimanoidea in 1967 by Wassersug and Hecht. Hassiacosuchus may be the same as Allognathosuchus; Christopher Brochu has recommended continuing to use Hassiacosuchus.
Macrocranion is a genus of extinct mammal from the Eocene epoch of Europe and North America. Exceptional fossils have has been found in the Messel Pit of Germany. Macrocranion species are often described as forest-floor predators, about the size of small squirrels but with longer limbs. The genus is represented at the Messel Pit site by two species, M. tupaidon and M. tenerum.
Allaeochelys is an extinct genus of Carettochelyid turtle, known from the Eocene to Miocene of Europe, Asia, North America and Africa.
Palaeopython is an extinct genus of snake from the Eocene of Europe. The genus has been used to refer to large Western and Central European snake vertebrae from the Eocene. P. cadurcensis and the tentatively-referred "P." neglectus originate from France; P. ceciliensis originates from Germany; and P. helveticus originates from Switzerland. A species known from multiple well-preserved specimens found in the Messel Pit of Germany, P. fischeri, was named by Stephan Schaal in 2004, but examination of the genus showed that it represented a distinct lineage; it was renamed Eoconstrictor fischeri in 2020 by Agustín Scanferla and Krister T. Smith. Another species from France, P. filholii, was moved to the genus Phosphoroboa in 2021 by Georgalis, Márton Rabi, and Smith. An additional species, P. sardus, was described in 1901 by Alessandro Portis from the Middle Miocene of Monte Albu. However, a reevaluation of the holotype specimen of this species revealed it to actually belong to an indeterminate acanthomorph fish.
Trionyx is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today T. triunguis, the African or Nile softshell turtle, is the only extant softshell still classified as Trionyx. The other species still assigned to this genus are only known from fossils. T. triunguis is a relatively large, aquatic piscivore.
Basilemys is a large, terrestrial trionychoid turtle from the Upper Cretaceous. In Greek, the word "Basil" means royal or kingly and the word "Emys" means turtle. Therefore, Basilemys means King Turtle. Basilemys has been found in rocks dating to the Campanian and Maastrichtian subdivisions of the Late Cretaceous and is considered to be the largest terrestrial turtle of its time. Basilemys has solely been found in North America. The family Nanhsiungchelyidae, which is the family Basilemys belongs to, made its first appearance in the Lower Cretaceous, in what we now call Asia. Because of Basilemys, we know that this family appeared in North America in the Upper Cretaceous. It is possible that Basilemys and other nanhsiungchelyids are immigrants from Asia. They might have arrived in North America by passing through what we now call the Bering Strait somewhere during the Cretaceous. In an analysis made by Sukhanov et al. on a new Nansiunghelyid turtle from the Upper Cretaceous of Mongolia, it was demonstrated that Asian nanhsiungchelyids gave rise to the North American nanhsiungchelyids. Basilemys shares some traits with another member of nanhsiungchelyidae, Zangerlia, which is similar to Basilemys in, for example, skull proportions. However, Basilemys has a more complex triturating surface that includes well-defined pockets on the dentary, and it also has tooth-like projections on the triturating surface of the maxilla.
Palaeovaranidae, formerly known as Necrosauridae, is an extinct clade of varanoid lizards known from the Paleogene of Europe. It contains three genera.
Drazinderetes is a large bodied genus of soft shell turtle from the Middle Eocene Drazinda Formation of Pakistan. Its presence in the shallow marine deposits of the Drazinda Formation suggests that Drazinderetes may have been a partially or fully marine animal. Indetermined trionychine remains from the same formation may suggest that Drazinderetes could have been among the largest known turtles, with one entoplastron indicating a potential length of 1.5 to 2.1 meters. Drazinderetes currently consists of only a single species: Drazinderetes tethyensis.
This is an overview of the paleofauna of the Eocene Messel Formation as explored by the Messel Pit excavations in Germany. A former quarry and now UNESCO World Heritage Site, the Messel Formation preserves what once were a series of anoxic lakes surrounded by a sub-tropical rainforest during the Middle Eocene, approximately 47 Ma.
