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

shrew opossum The family (biology), 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 mar ...

found on the eastern slopes of the

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 ...

in southern

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

Etymology

The origin of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

name (''Caenolestes'') drives from the

Greek Greek may refer to: Greece 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 ...

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

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 ...

name (''sangay'') derives from

Sangay National Park Sangay National Park ( es, Parque Nacional Sangay) 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 vol ...

, which is the largest

Andean The Andes, Andes Mountains or Andean Mountains (; ) are the List of mountain ranges#Mountain ranges by length, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range i ...

national park in

. The park itself is named after a

volcano A volcano is a rupture 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 often found where tectonic plates are ...

called

Sangay Sangay (also known as Macas, Sanagay, or Sangai) is an active stratovolcano in central Ecuador. It exhibits mostly strombolian activity. Geologically, Sangay marks the southern boundary of the Northern Volcanic Zone, and its position straddlin ...

, 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 Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República ...

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

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

-based

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

study showed that the Incan caenolestid and the long-nosed caenolestid (''Rhyncholestes raphanurus'') form a

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, ...

sister A sister is a woman or a girl who shares one or more parents 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 refer to ...

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

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

(nearly 55 mya).

References

{{Taxonbar, from=Q19277009 Shrew opossums Fauna of Ecuador Mammals described in 2013