Aerobius Temporal range: Late Cretaceous, | |
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Holotype specimen under various imaging techniques | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Tardigrada |
Class: | Eutardigrada |
Order: | Parachela |
Superfamily: | Hypsibioidea |
Genus: | † Aerobius Mapalo, Wolfe & Ortega-Hernández, 2024 |
Species: | †A. dactylus |
Binomial name | |
†Aerobius dactylus Mapalo, Wolfe & Ortega-Hernández, 2024 | |
Aerobius is a genus of extinct tardigrades ("water bears") of the superfamily Hypsibioidea. The genus contains a single species, A. dactylus, known from a single individual preserved in amber. The Aerobius holotype is preserved in the same piece of Late Cretaceous amber as Beorn , another extinct tardigrade. The specimen was found near Cedar Lake in Manitoba, Canada.
The Aerobius holotype specimen, MCZ PALE-4586 is embedded in a piece of amber collected in 1940 by William M. Legg in Manitoba, Canada. The type locality is near where the Saskatchewan River enters Cedar Lake. The individual is curled and notably shriveled. The holotype of Beorn is preserved in the same amber piece as Aerobius. In the 1964 description of Beorn, Kenneth W. Cooper noted the presence of a much smaller—seemingly poorly preserved—tardigrade potentially distinct from Beorne in the same amber matrix. However, he refrained from describing this individual due to his inability to reliably determine its anatomical details. New imaging techniques developed since then allowed for later researchers to describe the smaller specimen in detail. [1] [2]
In 2024, Mapalo, Wolfe & Ortega-Hernández described Aerobius dactylus as a new genus and species of tardigrade based on the smaller individual preserved in amber alongside Beorn. The generic name, Aerobius, is derived from the modified Greek prefix " aero- ", denoting "air", in reference to the holotype's apparent midair suspension in amber. The specific name, dactylus, is derived from the Latin word " dactylus ", meaning "finger", referencing the distinctive claws of the holotype. [1]
Aerobius represents one of the only known fossil tardigrade species. The first named tardigrade was Beorn in 1964. [2] It was followed by Milnesium swolenskyi —a species of the extant genus Milnesium from the Late Cretaceous (Turonian) of New Jersey—in 2000, representing the oldest known tardigrade. [3] Paradoryphoribius , the youngest known fossil tardigrade from the Miocene of the Dominican Republic, was named in 2021. [4] [1]
Like in other tardigrades, the general body shape of Aerobius is compact and barrel-like, with four short pairs of claw-tipped lobopodous legs. The size of the claws on the first, second, and third legs are generally similar, but the claws on the fourth leg are drastically different in size and shape.
In its shriveled state, the Aerobius holotype specimen measures about 0.10 millimeters in length. There are no clear protuberances on the cuticle. No eyespots are visible. An elliptical organ is faintly visible on the side of the head, and the mouth hole at the front of the head is smooth.
To determine the relationships of Aerobius, Mapalo, Wolfe & Ortega-Hernández (2024) phylogenetically analyzed a combination of morphological features and rRNA sequences. They recovered Aerobius and the contemporary Beorn as closely related members of the tardigrade family Hypsibioidea. These results are displayed in the cladogram below, with extinct species designated with a dagger (†): [1]
The Stephanidae, sometimes called crown wasps, are a family of parasitoid wasps. They are the only living members of the superfamily Stephanoidea. Stephanidae has at least 345 living species in 11 genera. The family is considered cosmopolitan in distribution, with the highest species concentrations in subtropical and moderate climate zones. Stephanidae also contain four extinct genera described from both compression fossils and inclusions in amber.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1964.
Tardigrades, known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär. In 1777, the Italian biologist Lazzaro Spallanzani named them Tardigrada, which means "slow steppers".
Parachela is an order of tardigrades in the class Eutardigrada. Members of this order have existed for at least 72 million years, up to the present. The oldest known species are Beorn leggi and Aerobius dactylus.
Coprinites is an extinct monotypic genus of gilled fungus in the Agaricales family Agaricaceae. At present it contains the single species Coprinites dominicana.
Archaeomarasmius is an extinct genus of gilled fungus in the Agaricales family Tricholomataceae, containing the single species Archaeomarasmius leggetti. It is known from two fruit bodies recovered from amber, one consisting of a complete cap with a broken stem, the other consisting of a fragment of a cap. The cap has a diameter ranging from 3.2 to 6 mm, while the stem is 0.5 mm (0.02 in) thick. Spores were also recovered from the amber, and are broadly ellipsoid to egg-shaped, measuring roughly 7.3 by 4.7 μm. The species, which resembles the extant genera Marasmius and Marasmiellus, is inferred to have been saprobic on plant litter or other forest debris.
Protomycena is an extinct monotypic genus of gilled fungus in the family Mycenaceae, of order Agaricales. At present it contains the single species Protomycena electra, known from a single specimen collected in an amber mine in the Cordillera Septentrional area of the Dominican Republic. The fruit body of the fungus has a convex cap that is 5 mm (0.2 in) in diameter, with distantly spaced gills on the underside. The curved stipe is smooth and cylindrical, measuring 0.75 mm (0.030 in) thick by 10 mm (0.39 in) long, and lacks a ring. It resembles extant species of the genus Mycena. Protomycena is one of only five known agaric fungus species known in the fossil record and the second to be described from Dominican amber.
Palaeoagaracites is an extinct monotypic genus of gilled fungus in the order Agaricales. It contains the single species Palaeoagaracites antiquus.
Plumalexius is a genus of wasps in the extinct monotypic family Plumalexiidae, containing two species: the type species Plumalexius rasnitsyni, known from the Late Cretaceous White Oaks Pit in Sayreville, New Jersey, and Plumalexius ohmkuhnlei, known from the Cretaceous Burmese amber.
Brownimecia is an extinct genus of ants, the only genus in the tribe Brownimeciini and subfamily Brownimeciinae of the Formicidae. Fossils of the identified species, Brownimecia clavata and Brownimecia inconspicua, are known from the Late Cretaceous of North America. The genus is one of several ants described from Late Cretaceous ambers of New Jersey. Brownimecia was initially placed in the subfamily Ponerinae, until it was transferred to its own subfamily in 2003; it can be distinguished from other ants due to its unusual sickle-like mandibles and other morphological features that makes this ant unique among the Formicidae. B. clavata is also small, measuring 3.43 millimetres (0.135 in), and a stinger is present in almost all of the specimens collected. The morphology of the mandibles suggest a high level of feeding specialization.
Zigrasolabis is an extinct genus of earwig in the family Labiduridae known from Cretaceous fossils found in Myanmar. The genus contains a single described species, Zigrasolabis speciosa.
Myanmyrma is an extinct genus of ants not placed into any Formicidae subfamily. Fossils of the single known species, Myanmyrma gracilis, are known from the Middle Cretaceous of Asia. The genus is one of several ants described from Middle Cretaceous ambers of Myanmar.
Cananeuretus is an extinct genus of ant in the Formicidae subfamily Aneuretinae, and is one of two Cretaceous genera of the subfamily. The genus contains a single described species Cananeuretus occidentalis and is known from one Late Cretaceous fossil which has been found in North America.
Burmaleon is an extinct genus of lacewing in the family Osmylidae known from fossils found in Asia. The genus contains a single species, Burmaleon magnificus.
Beorn is an extinct genus of tardigrade and the first known fossil tardigrade, discovered c. 1940 and described in 1964 from Late Cretaceous amber from Manitoba, Canada. The genus contains a single species, B. leggi. It was originally classified as the only member of its family, the Beornidae, but was later reclassified as belonging to the Hypsibiidae. It is one of three fossil tardigrades known from the Cretaceous, the others being Milnesium swolenskyi from the Turonian New Jersey amber and Aerobius from the same amber piece as Beorn. The only other confidently known fossil tardigrade is the Miocene Paradoryphoribius from the Dominican Republic.
Gerontoformica is an extinct genus of stem-group ants. The genus contains thirteen described species known from Late Cretaceous fossils found in Asia and Europe. The species were described between 2004 and 2016, with a number of the species formerly being placed into the junior synonym genus Sphecomyrmodes.
Baikuris is an extinct genus of ant in the Formicidae subfamily Sphecomyrminae, and is currently placed in the tribe Sphecomyrmini. The genus contains four described species: the type species Baikuris mandibularis, along with Baikuris casei, Baikuris maximus, Baikuris mirabilis, B. ocellantis.
New Jersey Amber, sometimes called Raritan amber, is amber found in the Raritan and Magothy Formations of the Central Atlantic (Eastern) coast of the United States. It is dated to the Late Cretaceous, Turonian age, based on pollen analysis of the host formations. It has been known since the 19th century, with several of the old clay-pit sites now producing many specimens for study. It has yielded a number of organism fossils, including fungi, plants, tardigrades, insects and feathers. The first identified Cretaceous age ant was described from a fossil found in New Jersey in 1966.
Milnesium swolenskyi is a species of tardigrade from the Cretaceous period. It, Beorn and Paradoryphoribius are the only known tardigrade genera in the fossil record. The type specimen AMNH NJ-796 was found in Turonian New Jersey amber, from about 93.9 to 89.8 million years ago (mya).
Paradoryphoribius is an extinct genus of tardigrades from the order Parachela. It is the third fossil tardigrade to be named, described in 2021 from Miocene Dominican amber from the Dominican Republic. The type, and currently only species, is P. chronocaribbeus. Paradoryphoribius is the first extinct tardigrade known from the Cenozoic and is also the first tardigrade known from the Miocene. It has a length of 539 microns.