Late Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "daw ...
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
. It has originally been assigned to the order
Pyrotheria
Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera ''Baguatherium'', ''Carolozittelia'', ''Colombitherium'', ''Griphodon'', ''Propyrotherium'', ''Proticia'', and '' Pyrotherium''.
They had ...
and the family
Colombitheriidae
Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera '' Baguatherium'', '' Carolozittelia'', ''Colombitherium'', '' Griphodon'', '' Propyrotherium'', ''Proticia'', and '' Pyrotherium''.
...
, although a later detailed analysis of the fossil questions that classification. A fossil jawbone of approximately length of ''Colombitherium'' has been found by Texas Petroleum in 1945, in the Upper Eocene strata of the middle Gualanday Group in the department of Tolima,
Central Ranges
Central Ranges (code CER) is an Australian bioregion, with an area of 101,640.44 square kilometres (39,244 sq mi) spreading across two states and one territory: South Australia, Western Australia, and the Northern Territory.Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
.
Etymology
The genus ''Colombitherium'' means "Beast from Colombia". The species
epithet
An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...
''tolimense'' refers to the
department
Department may refer to:
* Departmentalization, division of a larger organization into parts with specific responsibility
Government and military
*Department (administrative division), a geographical and administrative division within a country, ...
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
The genus is only known from a single jawbone with some teeth, found by Texas Petroleum in 1945, a specimen approximately in length, recovered from the Late Eocene middle part of the Gualanday Group on the San Pedro
finca
In English usage, a ''finca'' (; ) refers to a piece of rural or agricultural land, typically with a cottage, farmhouse or estate building present, and often adjacent to a woodland or plantation.
Overview
Especially in tourism, the term has ...
, Alto San José,
Chaparral
Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...
, Tolima. The teeth, molars and premolars of a kind known as bilophodont, which are present in the pyrotheres - were considered as evidence that this genus could be an ancestor of the advanced pyrotheres as ''
Pyrotherium
''Pyrotherium'' ('fire beast') is an extinct genus of South American ungulate, of the order Pyrotheria, that lived in what is now Argentina and Bolivia, during the Late Oligocene.Hoffstetter in 1970, with a revised interpretation published by Billet ''et al''. in 2010.Billet ''et al''., 2010, p.320 The detailed descriptions by Billet ''et al''. show the differences between ''Colombitherium'' and other pyrotherians: the features of the bilophodont teeth of Colombitherium are actually found in several groups of placental mammals, which implies that ''Colombitherium'' and another possibly related taxon, ''
Proticia
''Proticia'' is an extinct genus of mammals belonging to the order Pyrotheria. It lived during the Early Eocene, and its fossilized remains were discovered in South America.
Description
This animal is only known from a fragmentary mandible pr ...
'' could not be part of Pyrotheria. The authors maintain "the referral of ''Colombitherium'' to Pyrotheria is therefore weakly supported, and it must be considered as highly hypothetical."Billet et al., 2010, p.323 In any case, the lack of further evidence means that ''Colombitherium'' and ''Proticia'' must be classified in a separate
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
, Colombitheriidae which is tentatively classified as a primitive
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
in
Pyrotheria
Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera ''Baguatherium'', ''Carolozittelia'', ''Colombitherium'', ''Griphodon'', ''Propyrotherium'', ''Proticia'', and '' Pyrotherium''.
They had ...
.
Also the absolute age of the strata where the fossil jawbone has been found is questioned. The age has been originally defined by De Porta in 1962 on the basis of the
pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
Early Oligocene
The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chatti ...
age for the upper layers of the Gualanday Group.Billet et al., 2010, p.324