The eastern caenolestid (''Caenolestes sangay'') is a

shrew opossum The family Caenolestidae contains the seven surviving species of shrew opossum: small, shrew-like marsupials that are confined to the Andes mountains of South America. The order is thought to have diverged from the ancestral marsupial line very e ...

found on the eastern slopes of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

in southern

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

Etymology

The origin of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

name (''Caenolestes'') drives from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words ''kainos'' ("new") and ''lestes'' ("robber", "pirate"). The origin of the

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

name (''sangay'') derives from

Sangay National Park Sangay National Park () is a national park located in the Morona-Santiago, Chimborazo, Tungurahua, Cañar, and Azuay provinces of Ecuador. The park contains two active volcanoes (Tungurahua and Sangay), one extinct volcano El Altar (Kapak U ...

, which is the largest

Andean The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...

national park in

. The park itself is named after a

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

called

Sangay Sangay (also known as Macas, Sanagay, or Sangai) is an Volcano#Active, active stratovolcano in central Ecuador. It exhibits mostly Strombolian eruption, strombolian activity. Geologically, Sangay marks the southern boundary of the Northern Volc ...

, one of

's most active

es that lies within the park.

was the site of the discovery of the eastern caenolestid in 2010.

Taxonomy

The eastern caenolestid is one of the five members of ''

Caenolestes The common shrew opossums (genus ''Caenolestes'') are members of the family Caenolestidae. They are found in Colombia, Ecuador, Peru, and Venezuela. The most recently discovered species is ''C. sangay''. Phylogeny See also * List of mammal ...

'', and is placed in the family

Caenolestidae The family Caenolestidae contains the seven surviving species of shrew opossum: small, shrew-like marsupials that are confined to the Andes mountains of South America. The order is thought to have diverged from the ancestral marsupial line very e ...

(shrew opossums). In the latter part of 20th century, scientists believed that ''Caenolestes'' is closely related to ''Lestoros'' (the

Incan caenolestid The Incan caenolestid (''Lestoros inca''), also known as the Incan shrew opossum or Peruvian caenolestid, is a caenolestid found in the southern Peruvian Andes. It was first Species description, described by English zoologist Oldfield Thomas in 1 ...

). Over the years, it became clear that ''Lestoros'' is morphologically different from ''Caenolestes''. A 2013 morphological and

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

-based

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

study showed that the Incan caenolestid and the

long-nosed caenolestid The long-nosed caenolestid (''Rhyncholestes raphanurus''), also known as the Chilean shrew opossum or long-nosed shrew opossum, is a shrew opossum that occurs in temperate forests of Argentina and southern Chile. It was first described by America ...

(''Rhyncholestes raphanurus'') form a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

sister A sister is a woman or a girl who shares parents or a parent with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to ref ...

to ''Caenolestes''. The cladogram below is based on this study. Caenolestid fossils date to as early as the early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

(nearly 55 mya).

References

{{Taxonbar, from=Q19277009 Shrew opossums Mammals of the Andes Marsupials of Ecuador Endemic fauna of Ecuador Mammals described in 2013