Metanephrocerus groehni
   HOME

TheInfoList



OR:

''Metanephrocerus'' is an
extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus of big-headed flies in the
diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
n subfamily Protonephrocerinae, for which it is one of only two
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
. The genus contains four described species, ''Metanephrocerus belgardeae'', ''M. collini'', ''M. groehni'', and ''M. hoffeinsorum''. ''Metanephrocerus'' is known from a group of Middle Eocene fossils which were found in Europe and a single early Eocene fossil from North America.


History and classification

When first described, ''Metanephrocerus'' was known only from two separate fossils, the holotype female, and the female paratype were fossilized as inclusions in transparent chunks of Baltic amber. Baltic amber is approximately forty-six million years old, having been deposited during the Lutetian stage of the Middle Eocene. There is debate on what plant family produced the amber, with evidence supporting relatives of either an ''
Agathis ''Agathis'', commonly known as kauri or dammara, is a genus of 22 species of evergreen tree. The genus is part of the ancient conifer family Araucariaceae, a group once widespread during the Jurassic and Cretaceous periods, but now largely re ...
'' or a '' Pseudolarix'' relative. Fossils of the type species, ''M. collini'', were first studied by American entomologist
Frank M. Carpenter Frank Morton Carpenter (September 6, 1902 – January 18, 1994) was an American entomologist and paleontologist. He received his PhD from Harvard University, and was curator of fossil insects at the Harvard Museum of Comparative Zoology for 60 y ...
and F. M. Hull who placed the new species in the fossil genus ''
Protonephrocerus ''Protonephrocerus'' is a genus of flies belonging to the family Pipunculidae Pipunculidae is a family of flies (Diptera) commonly termed big-headed flies, a reference to the large (holoptic) eyes, which cover nearly the entire head. The fami ...
''. Carpenter and Hull's 1939
type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...
of the new species was published in the monograph series '' Bernstein-Forschungens''. The species was moved to the new genus ''Metanephrocerus'' in a 1948 paper by Martin L Aczél, and since that time both the type specimens have been lost and are considered possibly destroyed. After the ''M. collini'' description, 75 years passed before an additional three related species were described. Two of those, ''M. groehni'' and ''M. hoffeinsorum''. were described from solitary fossil inclusions in Baltic amber. The 2014 descriptions were made by Christian Kehlmaier, Manuel Dierick and Jeffrey H. Skevington, based on detailed CT scans of the specimens. They chose the species name "groehni" is a patronym honoring Carsten Gröhn, who supported the research of the authors, and who was the owner of the specimen before description. The fossil was to be deposited into the collections of the Geologisch-Paläontologisches Institut und Museum der Universität Hamburg Similarly, the epithet of the second species "hoffeinsorum" is a patronym for Christel and Hans-Werner Hoffeins for the donation of the type fossil to the
Senckenberg Deutsches Entomologisches Institut The Senckenberg German Entomological Institute (german: Senckenberg Deutsches Entomologisches Institut, SDEI or DEI) is a German entomological research institute devoted to the study of insects. Founded in 1886, the institute has an extraordina ...
and for their support of the authors research. The third related species, ''M. belgardeae'', bringing the total to four, was described from a compression fossil found in the early Eocene, Ypresian
Klondike Mountain Formation The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Wash ...
lagerstätten, its discovery expanding both the temporal range and geographic range. ''M. belgardeae'' was described by S. Bruce Archibald, Christian Kehlmaier, and Rolf Mathewes from a single partial female. The
specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
is a matronym of Azure Rain Belgarde, who collected the type specimen, SR 08-06-02, and donated it to the Stonerose Interpretive Center. Placement of the group has changed several times, with ''Metanephrocerus'' and ''Protonephrocerus'' being placed in the pipunculid subfamily
Nephrocerinae Nephrocerinae is a subfamily of big-headed flies (insects in the family Pipunculidae). Genera * Tribe Nephrocerini ** Genus ''Nephrocerus'' Zetterstedt, 1838 * Tribe ''incertae sedis'' ** Genus '' Priabona'' Archibald, Kehlmaier & Mathewes, 201 ...
as tribe Protonephrocerini from 1948 until 2014. The placement of the tribe was challenged in 2014 by Kehlmaier, Dierick and Skevington who suggested inclusion of the genera made Nephrocerinae
paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
. As such they elevated the tribe Protonephrocerini to the subfamily rank as Protonephrocerinae, leaving only ''
Nephrocerus ''Nephrocerus'' is a genus of flies belonging to the family Pipunculidae. The species of this genus are found in Europe, Asia and Northern America. Species *'' Nephrocerus acanthostylus'' Skevington, 2005 *'' Nephrocerus atrapilus'' Skevington, ...
'' and '' Priabona'' in Nephrocerinae.


Description

''Metanephrocerus belgardeae'' is a large species, with a wing length of , and a
hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...
wing coloration, broken by a smokey tone to the
pterostigma The pterostigma (plural: pterostigmata) is a group of specialized cells in the outer insect wing, wings of insects, which are often thickened or coloured, and thus stand out from other cells. It is particularly noticeable in dragonfly, dragonfli ...
and basal area of the wing. The wing has a long third section of the costal vein and the median vein that is long and straight. The females abdomen is approximately long, with short setae on the tergites, which grade to longer tergites on the first and second tergites. The short abdominal setae are distinct for the genus and exclude the species from other pipnculid genera. ''M. collini'' was known from 2 female specimens, which had hyaline wings with colored pterostigma. ''M. groehni'' is a nearly complete male fly with a total body length of , and is only missing the tip of the left hind leg. The hind legs show a distinct chaetotaxy to the setae, with front sides having setae that are longer than the femur is wide. The eyes connect for three times the length of the frons. The wings are , though the wings are folded slightly and difficult to fully assess. The halters are darkened at the base and on the knob. ''M. hoffeinsorum'' is a whole male, though large portions of it are enclosed in white mold and the specimen has a total length of . The wings show a length of and have a covering of
microtrichia Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...
. As with ''M. groehni'' the halters have darkened knobs and bases and the pteropleuron has 6 hairs on it. Tergite three of the abdomen is 1.3 times as long as tergite two.


References

{{Taxonbar, from=Q18926236 Ypresian insects Fossils of the United States Fossil taxa described in 2014 Fossil taxa described in 1939 Prehistoric insects of Europe Prehistoric insects of North America Pipunculidae Baltic amber Priabonian insects
A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species). It is one of the modern descendan ...
Taxa named by Frank M. Carpenter Klondike Mountain Formation Prehistoric Diptera genera