Pseudarmadillo Tuberculatus
   HOME

TheInfoList



OR:

''Pseudarmadillo tuberculatus'' 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 ...
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 ...
of
isopod Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...
in the family Delatorreiidae known from a series of possibly
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
fossils found 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 ''P. tuberculatus'' was one of two '' Pseudarmadillo'' species known from the fossil record and one of only two from Hispaniola.


History and classification

''P. tuberculatus'' is known from four isopods, both female and male, all of which are
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 disabiliti ...
s in three different 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 ...
. Two of the
paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...
s are fossils in the same amber specimen while the other two individuals are both in separate amber specimens. The amber specimens which entomb 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 paratypes, are currently preserved in the Division of Invertebrate Zoology collections at the
Staatliches Museum für Naturkunde 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
Stuttgart Stuttgart (; Swabian: ; ) is the capital and largest city of the German state of Baden-Württemberg. It is located on the Neckar river in a fertile valley known as the ''Stuttgarter Kessel'' (Stuttgart Cauldron) and lies an hour from the ...
, Germany. The type specimens were collected from an undetermined amber mine, in fossil bearing rocks of 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 ...
mountains, northern
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 was produced by resin from the extinct tree ''
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 amber dates from at least 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, based on studying the associated fossil
foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...
and may be as old as the Middle Eocene, based on the associated fossil
coccoliths Coccoliths are individual plates or scales of calcium carbonate formed by coccolithophores (single-celled phytoplankton such as ''Emiliania huxleyi'') and cover the cell surface arranged in the form of a spherical shell, called a ''coccosphere''. ...
. This age range is due to the host rock being secondary deposits for the amber, and the Miocene the age range is only the youngest that it might be. The fossil isopods were first studied by paleontologist Helmut Schmalfuss of the Staatliches Museum für Naturkunde Stuttgart. Schmalfuss's 1984
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 journal ''Stuttgarter Beiträge zur Naturkunde. Serie B (Geologie und Paläontologie)'' and no explanation of 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 ...
''tuberculatus'' was given. ''P. tuberculatus'' is one of the first two species of ''Pseudarmadillo'' described from the fossil record, the other species being '' Pseudarmadillo cristatus''. Both are known only from Dominican amber and were described in the same 1984 paper.


Description

The ''Pseudarmadillo tuberculatus'' specimens are moderately well preserved, though since isopods lack the wax coatings found in insects, they show deterioration and distortion from the
resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...
after entombment. The species has an estimated adult body length of up to approximately and a width of . In contrast to ''P. cristatus'' which has two ribs running the length of the body on each side, only one rib is on each side of ''P. tuberculatus''. While both species have two rows of bumps running the width of the body between the ribs on each body segment, the front row of bumps is eleven across and the posterior row is ten across in ''P. tuberculatus'' rather the row and five and four in ''P. cristatus''. The
cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont Company. Baldino s ...
has notably enlarged antennal lobes that served to shelter the antenna when an individual curled into a defensive ball. The compound eyes of the species are composed five
ommatidia The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium). An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The ou ...
.


References

{{Taxonbar, from=Q3911814 Woodlice Miocene crustaceans Fauna of Hispaniola Fossil taxa described in 1985