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 ...
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
Myrmicinae
Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and ...
known from two
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene.
The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...
fossils found in
amber
Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...
on
Hispaniola
Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...
. At the time of description, ''C. dieteri'' was one of seven fossil ant species placed in the ''Cephalotes'' ''coffeae'' clade.
History and classification
''Cephalotes dieteri'' was described from two fossil ants which are preserved as
inclusion
Inclusion or Include may refer to:
Sociology
* Social inclusion, aims to create an environment that supports equal opportunity for individuals and groups that form a society.
** Inclusion (disability rights), promotion of people with disabilitie ...
s in transparent chunks of
Dominican amber
Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree ''Hymenaea protera''.
Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil incl ...
. The amber was produced by the extinct ''
Hymenaea protera
''Hymenaea protera'' is an extinct prehistoric leguminous tree, the probable ancestor of present-day ''Hymenaea'' species. Most neotropical ambers come from its fossilized resin, including the famous Dominican amber.
''H. protera'' once grew in ...
'', which formerly grew on
Hispaniola
Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...
, across northern South America and up to southern Mexico. The specimens were collected from unidentified amber mines in the
Dominican Republic
The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...
. The amber dates from the
Burdigalian
The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...
stage of the Miocene, being recovered from sections of the
La Toca Formation
The La Toca Formation is a geologic formation in the northern and eastern part of the Dominican Republic. The formation, predominantly an alternating sequence of marls and turbiditic sandstones, breccias and conglomerates, is renowned for the p ...
in the
Cordillera Septentrional
The Cordillera Septentrional is a mountain range that runs parallel to the north coast of the Dominican Republic, with extensions to the northwest as Tortuga island in Haiti, and to the southeast through lowlands to where it rises as the Sierra d ...
and the
Yanigua Formation
The Yanigua Formation is a geologic formation in Dominican Republic. The lagoonal claystones and marls preserve fossils dating back to the Miocene period.
At the time of description, the
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
and paratype specimens were both preserved in the collections of the
State Museum of Natural History Stuttgart
The State Museum of Natural History Stuttgart (german: Staatliches Museum für Naturkunde Stuttgart), abbreviated SMNS, is one of the two state of Baden-Württemberg's natural history museums. Together with the State Museum of Natural History ...
in Germany. Living and fossil ''Cephalotes'', ''Eucryptocerus'', ''Exocryptocerus'' and ''Zacryptocerus'' ants were examined in 1999 by Maria L. De Andrade and Cesare Baroni Urbani with a redescription of included species being published in the journal ''Stuttgarter Beiträge zur Naturkunde. Serie B (Geologie und Paläontologie)''. The two fossils were first described in the paper along with a number of fossils and were placed into the new species ''Cephalotes dieteri''. De Andrade and Baroni Urbani coined 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 ...
''dieteri'' as a
patronym
A patronymic, or patronym, is a component of a personal name based on the given name of one's father, grandfather (avonymic), or an earlier male ancestor.
Patronymics are still in use, including mandatory use, in many countries worldwide, alt ...
honoring Dieter Schlee, who was responsible for amassing the Stuttgart amber collections that housed many of the specimens studied.
Phylogeny
In the study of ''Cephalotes'' by de Andrade and Baroni Urbani ''C. dieteri'' was grouped into the ''coffeae'' clade consisting of seven extinct species and four extant species. The clade shares two, possibly three distinct features between the species. Segment three of the abdomen is modified into a post petiole which in turn is modified to have large side wings. Additionally the first
sternite
The sternum (pl. "sterna") is the ventral portion of a segment of an arthropod thorax or abdomen.
In insects, the sterna are usually single, large sclerites, and external. However, they can sometimes be divided in two or more, in which case the ...
of the gaster has a simple reticulated surface sculpturing.
Description
Workers of ''C. dieteri'' range in length between , and a head length of . The frontal ridges on the face, rear corners of the head along with the borders of the pronotal and gastral wings are a lighter coloration than the rest of the workers bodies. The exoskeleton is covered with varying sized reticulation, and hairs of several types are present. There are two long thin hairs present on the second tergite of the gaster, while the rear borders of the hind gasteral tergites have rare club-tipped hairs. The head is shorter than wide, with truncated rear corners and a concave rear edge. The face has two raised ridges that have crenulated margins, and the rear corners are also crenulated. The pronotum with a narrow, long, continuous suture, while the mesonotum and the petiole are both unarmed, lacking the larger spines seen on other species. The denser reticulation of the exoskeleton, along with the slightly smaller head size separates ''C. dieteri'' from its sister species '' Cephalotes integerrimus'', also from Dominican amber.