Ypresiomyrma
Encyclopedia
Ypresiomyrma is an extinct genus
of bulldog ants in the subfamily Myrmeciinae
which contains three described species. One species is known from the Isle of Fur
in Denmark and two are from British Columbia, Canada.
in Cambridge, Massachusetts
. They published their 2006 description of the genus and species in an Annals of the Entomological Society of America journal article. The genus name is a combination of Ypresian
, referring to the age of the specimens and the Greek
, meaning "ant".
Along with the genus description, the paper contained descriptions of the type species Ypresiomyrma orbiculata and Ypresiomyrma bartletti, both from the McAbee locality in British Columbia. Archibald, Cover and Moreau also included a redescription of the Danish species Pachycondyla rebekkae under the new name combination Ypresiomyrma rebekkae.
and the abdomen
in Ypresiomyrma is composed of a single segment. The mandibles are a distinct triangular shape and shorter in length then the head capsule. Queens
of the genus are large, being over 20 millimetre (0.78740157480315 in) in length.
McAbee locality, Kamloops Group, near Cache Creek, British Columbia
. The specimen, numbered UCCIPR L-18 F-749 and UCCIPR L-18 F-750 for the part and counterpart respectively, is currently preserved in the paleoentomology
collections housed at Thompson Rivers University
, in Kamloops, British Columbia
. Archibald, Cover, and Moreau coined the specific epithet
from the Latin
"orbiculatus", meaning "rounded" or "circular", in reference to the shape of the head. The species is discernible from the other two species of Ypresiomyrma by its notably rounded head capsule, and by the shape of the petiole
which is a smoothly sloping convex shape with a node in the center. The queen is estimated to have been approximately 25 millimetre (0.984251968503937 in) in length.
collections as GSC 127632a and GSC 127632b. The shape of head is subtriangular, which separates it from Y. orbiculata, and at an estimated 20 millimetre (0.78740157480315 in) it is smaller than Y. rebekkae. The petiole shape in Y. bartletti is distinct from both other species. The specific epithet was chosen in honor of Rod Bartlett who collected the specimen, and to honor his work with the Vancouver Paleontological Society and the British Columbia Paleontological Alliance.
Ølst and Fur Formation
s. The specimens were first studied and described by Jes Rust and N. Møller Andersen in 1999, and they named the species for Rebekka Madsen who collected the type specimen in September 1994. The part and counterpart, GMUC No. 1995 8B and GMUC No. 1995 8A are deposited in the Geological Museum of the University of Copenhagen
. At that time Rust and Andersen placed the species into the modern ponerin
genus Pachycondyla
based on the shape of the abdominal segment VI and lack of dentition on the mandibles. Archibald, Cover, and Moreau moved the species to Ypresiomyrma based on the similarity to the McAbee species, by the shape of the abdominal segment III, which differs from that found in the Ponerinae subfamily genera, and by the morphology of the petiole. The species is known almost exclusively from queens, with only one known male ant assigned to it by Rust and Andersen.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of bulldog ants in the subfamily Myrmeciinae
Myrmeciinae
The Myrmeciinae is a subfamily of the Formicidae that was once found worldwide but is now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate and reproduce, thus sustaining the colony after...
which contains three described species. One species is known from the Isle of Fur
Fur (island)
Fur is a small Danish island in the Limfjord at the northern tip of the Salling peninsula. Fur has under 900 inhabitants. The island covers an area of 22 km². It is located at ....
in Denmark and two are from British Columbia, Canada.
History and classification
Fossils of Ypresiomyrma were first studied and described by Bruce Archibald, Stefan Cover and Corrie Moreau of the Museum of Comparative ZoologyMuseum of Comparative Zoology
The Museum of Comparative Zoology, full name "The Louis Agassiz Museum of Comparative Zoology", often abbreviated simply to "MCZ", is a zoology museum located on the grounds of Harvard University in Cambridge, Massachusetts. It is one of three museums which collectively comprise the Harvard Museum...
in Cambridge, Massachusetts
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...
. They published their 2006 description of the genus and species in an Annals of the Entomological Society of America journal article. The genus name is a combination of Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
, referring to the age of the specimens and the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
, meaning "ant".
Along with the genus description, the paper contained descriptions of the type species Ypresiomyrma orbiculata and Ypresiomyrma bartletti, both from the McAbee locality in British Columbia. Archibald, Cover and Moreau also included a redescription of the Danish species Pachycondyla rebekkae under the new name combination Ypresiomyrma rebekkae.
Description
There are several characteristics that separate Ypresiomyrma from other ant genera. The waist connecting the thoraxThorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
and the abdomen
Gaster
The gaster is the bulbous posterior portion of the metasoma found in Apocrita Hymenoptera . This begins with abdominal segment III on most ants, but some make a postpetiole out of segment III, in which case the gaster begins with abdominal segment IV....
in Ypresiomyrma is composed of a single segment. The mandibles are a distinct triangular shape and shorter in length then the head capsule. Queens
Eusociality
Eusociality is a term used for the highest level of social organization in a hierarchical classification....
of the genus are large, being over 20 millimetre (0.78740157480315 in) in length.
Y. orbiculata
Y. orbiculata was described from a single part and counterpart compression fossil found at the Middle YpresianYpresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
McAbee locality, Kamloops Group, near Cache Creek, British Columbia
Cache Creek, British Columbia
Cache Creek is a junction community northeast of Vancouver in British Columbia, Canada. It is on the Trans-Canada Highway in the province of British Columbia at its junction with northbound Highway 97...
. The specimen, numbered UCCIPR L-18 F-749 and UCCIPR L-18 F-750 for the part and counterpart respectively, is currently preserved in the paleoentomology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
collections housed at Thompson Rivers University
Thompson Rivers University
Thompson Rivers University is a comprehensive university located in Kamloops, British Columbia, Canada. It offers students a broad range of courses, career streams, and the ability to ladder credits from diploma programs into full degrees...
, in Kamloops, British Columbia
Kamloops, British Columbia
Kamloops is a city in south central British Columbia, at the confluence of the two branches of the Thompson River and near Kamloops Lake. It is the largest community in the Thompson-Nicola Regional District and the location of the regional district's offices. The surrounding region is more commonly...
. Archibald, Cover, and Moreau coined the specific epithet
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
"orbiculatus", meaning "rounded" or "circular", in reference to the shape of the head. The species is discernible from the other two species of Ypresiomyrma by its notably rounded head capsule, and by the shape of the petiole
Petiole (insect)
In entomology, the term petiole is most commonly used to refer to the constricted first metasomal segment of members of the Hymenopteran suborder Apocrita; it may be used to refer to other insects with similar body shapes, where the metasomal base is constricted...
which is a smoothly sloping convex shape with a node in the center. The queen is estimated to have been approximately 25 millimetre (0.984251968503937 in) in length.
Y. bartletti
The second species described from the McAbee site is Y. bartletti which, like Y. orbiculata, is known from a single specimen. The holotype part and counterpart are included in the Geological Survey of Canada, OttawaOttawa
Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...
collections as GSC 127632a and GSC 127632b. The shape of head is subtriangular, which separates it from Y. orbiculata, and at an estimated 20 millimetre (0.78740157480315 in) it is smaller than Y. rebekkae. The petiole shape in Y. bartletti is distinct from both other species. The specific epithet was chosen in honor of Rod Bartlett who collected the specimen, and to honor his work with the Vancouver Paleontological Society and the British Columbia Paleontological Alliance.
Y. rebekkae
This species is known from over 100 specimens collected from the earliest YpresianYpresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
Ølst and Fur Formation
Fur Formation
Essentially the Fur Formation is defined as a clayey diatomite with a lage number of volcanic ash layers.The Fur Formation is a marine geological formation of Ypresian age which crops out in the Limfjord region of Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs...
s. The specimens were first studied and described by Jes Rust and N. Møller Andersen in 1999, and they named the species for Rebekka Madsen who collected the type specimen in September 1994. The part and counterpart, GMUC No. 1995 8B and GMUC No. 1995 8A are deposited in the Geological Museum of the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
. At that time Rust and Andersen placed the species into the modern ponerin
Ponerinae
Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 28 extant genera, including Dinoponera gigantea - one of the world's largest species of ant....
genus Pachycondyla
Pachycondyla
Pachycondyla is a diverse group of ponerine ants that are widespread in the world's tropics and subtropics. Most are general predators or scavengers, with some specializing in hunting termites. In some species queens are replaced by fertilised workers...
based on the shape of the abdominal segment VI and lack of dentition on the mandibles. Archibald, Cover, and Moreau moved the species to Ypresiomyrma based on the similarity to the McAbee species, by the shape of the abdominal segment III, which differs from that found in the Ponerinae subfamily genera, and by the morphology of the petiole. The species is known almost exclusively from queens, with only one known male ant assigned to it by Rust and Andersen.