Transandinomys talamancae
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''Transandinomys talamancae'' is a
rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...
in the
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 ...
Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...
that occurs from
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
to southwestern
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 ...
and northern
Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
. Its habitat consists of lowland forests up to above
sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
. With a body
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...
of , it is a medium-sized
rice rat Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of S ...
. The fur is soft and is reddish to brownish on the upperparts and white to
buff Buff or BUFF may refer to: People * Buff (surname), a list of people * Buff (nickname), a list of people * Johnny Buff, ring name of American world champion boxer John Lisky (1888–1955) * Buff Bagwell, a ring name of American professional ...
on the
underparts Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
. The
tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
is dark brown above and lighter below and the ears and feet are long. The
vibrissae Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...
(whiskers) are very long. In the skull, the rostrum (front part) is long and the
braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skul ...
is low. The number of
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s varies from 34 to 54. The species was first described in 1891 by
Joel Asaph Allen Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoology, zoologist, mammalogy, mammalogist, and ornithology, ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and ma ...
and thereafter a variety of names, now considered
synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
, were applied to local populations. It was lumped into a widespread species "''Oryzomys capito''" (now ''
Hylaeamys megacephalus ''Hylaeamys megacephalus'', also known as Azara's broad-headed oryzomys or the large-headed rice rat, is a species of rodent in the genus ''Hylaeamys'' of family Cricetidae, of which it is the type species. It is found mainly in lowland tropical ...
'') from the 1960s until the 1980s and the current allocation of synonyms dates from 1998. It was placed in the genus ''
Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and ...
'' until 2006, as ''Oryzomys talamancae'', but is not closely related to the
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 ...
of that genus and was therefore moved to a separate genus ''Transandinomys'' in 2006. It shares this genus with '' Transandinomys bolivaris'', which has even longer vibrissae; the two overlap broadly in distribution and are morphologically similar. Active during the night, ''Transandinomys talamancae'' lives on the ground and eats plants and insects. Males move more and have larger
home range A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. He ...
s than most females. It breeds throughout the year, although few individuals survive for more than a year. After a
gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...
period of about 28 days, two to five young are born, which reach
sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definitio ...
within two months. A variety of
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s occur on this species. Widespread and common, it is of no conservation concern.


Taxonomy

In 1891,
Joel Asaph Allen Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoology, zoologist, mammalogy, mammalogist, and ornithology, ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and ma ...
was the first to scientifically describe ''Transandinomys talamancae'', when he named ''Oryzomys talamancae'' from a specimen from Talamanca, Costa Rica. He placed it in the genus ''
Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and ...
'', then more broadly defined than it is now, and compared it to both the
marsh rice rat The marsh rice rat (''Oryzomys palustris'') is a semiaquatic North American rodent in the family Cricetidae. It usually occurs in wetland habitats, such as swamps and salt marshes. It is found mostly in the eastern and southern United States, fr ...
(''O. palustris'') and to '' O. laticeps''. Several other names that are now recognized as
synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
of ''Transandinomys talamancae'' were introduced in the following years. In 1899, Allen described ''Oryzomys mollipilosus'', ''O. magdalenae'', and ''O. villosus'' from Magdalena Department, Colombia.
Oldfield Thomas Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and subspecies for the first time. He was appoin ...
added ''O. sylvaticus'' from
Santa Rosa Santa Rosa is the Italian, Portuguese and Spanish name for Saint Rose. Santa Rosa may also refer to: Places Argentina *Santa Rosa, Mendoza, a city * Santa Rosa, Tinogasta, Catamarca * Santa Rosa, Valle Viejo, Catamarca * Santa Rosa, La Pampa * S ...
, Ecuador in 1900 and ''O. panamensis'' from
Panama City Panama City ( es, Ciudad de Panamá, links=no; ), also known as Panama (or Panamá in Spanish), is the capital and largest city of Panama. It has an urban population of 880,691, with over 1.5 million in its metropolitan area. The city is locat ...
, Panama, in 1901. In the same year, Wirt Robinson and Markus Lyon named ''Oryzomys medius'' from near
La Guaira La Guaira () is the capital city of the Venezuelan state of the same name (formerly named Vargas) and the country's main port. It was founded in 1577 as an outlet for Caracas, to the southeast. The town and the port were badly damaged during ...
, Venezuela. Allen added ''O. carrikeri'' from Talamanca, Costa Rica, in 1908.
Edward Alphonso Goldman Edward Alphonso Goldman (July 7, 1873 – September 2, 1946) was an American zoologist and botanist. He worked extensively in Mexico with Edward William Nelson and described and revised many groups of mammals. He was born Edward Alphonso Goltman i ...
revised North American ''Oryzomys'' in 1918. He placed both ''panamensis'' and ''carrikeri'' as synonyms of ''Oryzomys talamancae'' and mentioned ''O. mollipilosus'' and ''O. medius'' as closely related species. ''O. talamancae'' was the only member of its own species group, which Goldman regarded as closest to ''Oryzomys bombycinus'' (='' Transandinomys bolivaris''). In 1960, Philip Hershkovitz listed ''talamancae'', ''medius'', ''magdalenae'', ''sylvaticus'', and ''mollipilosus'' among the many synonyms of "''Oryzomys laticeps''", a name later replaced by "''Oryzomys capito''". The species remained lumped under ''Oryzomys capito'' until 1983, when Alfred Gardner again listed it as a valid species, an action more fully documented by
Guy Musser Guy Graham Musser (August 10, 1936 – October 2019) was an American zoologist. His main research was in the field of the rodent subfamily Murinae, in which he has described many new species. Musser was born in Salt Lake City, Utah. He attended ...
and Marina Williams in 1985.Musser and Williams, 1985, p. 9 Musser and Williams also found that 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 ...
of ''Oryzomys villosus'', the affinities of which had been disputed, in fact consisted of a skin of ''O. talamancae'' and a skull of the ''Oryzomys albigularis'' group (equivalent to the current genus ''
Nephelomys ''Nephelomys'' is a genus of South American oryzomyine rodents found in the Andes from Bolivia to Venezuela, with a westward extension into the mountains of Costa Rica. Its generic name is derived from the Ancient Greek word ''nephelê'' "mist", ...
''). They restricted the name to the skin, making ''villosus'' a synonym of ''O. talamancae''.Musser and Williams, 1985, p. 7 They also examined the holotypes of ''panamensis'', ''carrikeri'', ''mollipilosus'', ''medius'', and ''magdalenae'' and identified them as examples of ''Oryzomys talamancae''. Additionally, they included ''sylvaticus'' and ''Oryzomys castaneus'' J.A. Allen, 1901, from Ecuador as synonyms, but without examining the holotypes. Musser and colleagues reviewed the group again in 1998 and confirmed that ''sylvaticus'' represents ''Oryzomys talamancae''; however, they found that ''castaneus'' was in fact an example of ''Oryzomys bolivaris'' (the current ''Transandinomys bolivaris''). In 2006, Marcelo Weksler published a
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 ...
analysis of
Oryzomyini Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of S ...
("rice rats"), the
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...
to which ''Oryzomys'' is allocated, using morphological data and
DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
s from the IRBP gene. His results showed species of ''Oryzomys'' dispersed across Oryzomyini and suggested that most species in the genus should be allocated to new genera. ''Oryzomys talamancae'' was also included; it appeared within " clade B", together with other species formerly associated with ''Oryzomys capito''. Some analyses placed it closest to species now placed in ''
Euryoryzomys ''Euryoryzomys'' is a genus of rodents in the tribe Oryzomyini of family Cricetidae. It includes six species, which are distributed in South America. Until 2006, its members were included in the genus ''Oryzomys'', but they are not closely related ...
'' or ''
Nephelomys ''Nephelomys'' is a genus of South American oryzomyine rodents found in the Andes from Bolivia to Venezuela, with a westward extension into the mountains of Costa Rica. Its generic name is derived from the Ancient Greek word ''nephelê'' "mist", ...
'', but with low support. Later in the same year, he, together with Alexandre Percequillo and Robert Voss, named ten new genera for species previously placed in ''Oryzomys'', including ''
Transandinomys ''Transandinomys'' is a genus of rodents in the tribe Oryzomyini of family Cricetidae. It includes two species—'' T. bolivaris'' and '' T. talamancae''—found in forests from Honduras in Central America south and east to southwester ...
'', which has ''Oryzomys talamancae'' (now ''Transandinomys talamancae'') as its
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 ...
. They also included ''Oryzomys bolivaris'', which was not included in Weksler's phylogenetic study, in this new genus. The two species are morphologically similar, but Weksler and colleagues could identify only one
synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
(shared-derived trait) for them: very long superciliary vibrissae (
vibrissa Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...
e, or whiskers, above the eyes).Weksler et al., 2006, p. 26 ''Transandinomys'' is one of about 30 genera in Oryzomyini, a diverse assemblage of American rodents of over a hundred species, and on higher taxonomic levels in the subfamily
Sigmodontinae The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the specie ...
of family
Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...
, along with hundreds of other species of mainly small rodents. Several
common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
s have been proposed for ''Transandinomys talamancae'', including "Talamanca Rice Rat",Goldman, 1918, p. 73 "Transandean Oryzomys", and "Talamancan Rice Rat".


Description

''Transandinomys talamancae'' is a medium-sized, brightly colored rice rat. It is similar to ''T. bolivaris'' and the two are often confused.Musser et al., 1998, p. 125 They are about as large, but in ''T. talamancae'' the tail is longer and the hindfeet shorter.Musser et al., 1998, p. 127 Both species share uniquely long vibrissae, with both the mystacial (above the mouth) and superciliary vibrissae extending to or beyond the back margin of the ears when laid back against the head, but those in ''T. bolivaris'' are substantially longer. '' H. alfaroi'', a widespread species ranging from Mexico to Ecuador, is also similar. It is smaller and darker, but young adult ''T. talamancae'' are similar in color to adult ''H. alfaroi'' and often misidentified.Musser et al., 1998, p. 169 ''
Hylaeamys megacephalus ''Hylaeamys megacephalus'', also known as Azara's broad-headed oryzomys or the large-headed rice rat, is a species of rodent in the genus ''Hylaeamys'' of family Cricetidae, of which it is the type species. It is found mainly in lowland tropical ...
'', with which ''T. talamancae'' was synonymized for some decades, is similar in body size, but is not known to overlap with ''T. talamancae'' in range. The fur is short, dense and soft in ''Transandinomys talamancae'';Musser and Williams, 1985, p. 14 in ''T. bolivaris'', it is longer and even more soft and dense. The color of the upperparts varies from reddish to brownish, becoming lighter towards the sides and the cheeks. The underparts are white to
buff Buff or BUFF may refer to: People * Buff (surname), a list of people * Buff (nickname), a list of people * Johnny Buff, ring name of American world champion boxer John Lisky (1888–1955) * Buff Bagwell, a ring name of American professional ...
, with the bases of the hairs plumbeous (lead-colored). The fur of ''T. bolivaris'' is darker: dark brown above and dark gray below. ''H. megacephalus'' also has darker fur.Musser et al., 1998, p. 173 Juveniles have thin, gray fur, which is
molt In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
ed into the dark brown subadult fur when the animal is about 35 to 40 days old. This fur is replaced by the bright adult fur at age 49 to 56 days.Fleming, 1970, p. 479 Juveniles are never blackish as in ''T. bolivaris''.Musser et al., 1998, pp. 128–129 The ears are dark brown, large, and densely covered with very small hairs. The sparsely haired tail is approximately as long as the head and body.Goldman, 1918, p. 71 It is dark brown above and lighter below. In contrast, the tail of ''H. megacephalus'' has little to no difference in color between the upper and lower surface. In 2006, Weksler and colleagues noted tail coloration as a difference between the two species of ''Transandinomys'' (bicolored in ''T. talamancae'' and unicolored in ''T. bolivaris''), but in their 1998 study, Musser and colleagues could not find differences in tail coloration between their Panamanian samples of the two species.Musser et al., 1998, p. 129 The hindfeet are long and have the three central digits longer than the two outer ones. They are white to pale yellow above, where the foot is covered with hairs, which are longer than in ''T. bolivaris''.Musser et al., 1998, p. 131 The digits of the hindfeet are surrounded by
ungual tufts In mammals, ungual tufts are tufts of hairs at the base of claws of the forefeet and hindfeet. Their presence has been used as a character in cladistic studies of the Cricetidae, a large family of rodents.Weksler, 2006, p. 19 Rice rats Membe ...
of silvery hair that are longer than the claws themselves. The claws are short and sharp.Goldman, 1918, p. 72 Parts of the sole are covered by indistinct scales ( squamae), which are usually entirely absent in ''T. bolivaris''. The
pads Pads (also called leg guards) are a type of protective equipment used in a number of sports and serve to protect the legs from the impact of a hard ball, puck, or other object of play travelling at high speed which could otherwise cause injuries t ...
are moderately large. The length of the head and body is , tail length , hindfoot length , ear length , and body mass . As in most oryzomyines, females have eight
mammae A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primat ...
. There are 12
thoracic vertebra In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...
with associated ribs, 7 lumbars, and 29 caudals; a pair of supernumerary (additional) ribs is occasionally present.


Skull and teeth

The skull has a long rostrum (front part), a broad
interorbital region The interorbital region of the skull is located between the eyes, anterior to the braincase. The form of the interorbital region may exhibit significant variation between taxonomic groups. In oryzomyine rodents, for example, the width, form, an ...
(between the eyes), and a low
braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skul ...
. It differs from that of ''T. bolivaris'' in various proportions, which are more apparent in adults than in juveniles; the skull of ''H. megacephalus'' is distinctly larger. The
zygomatic plate In rodent anatomy, the zygomatic plate is a bony plate derived from the flattened front part of the zygomatic arch (cheekbone). At the back, it connects to the front (maxillary) root of the zygomatic arch, and at the top it is connected to the ...
is broad and includes a well-developed zygomatic notch at its front. Its back margin is level with the front of the first upper molar. The
zygomatic arch In anatomy, the zygomatic arch, or cheek bone, is a part of the skull formed by the zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal process of the zygomati ...
(cheekbone) is heavy. The nasal and
premaxillary The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
bones extend about as far backward. The interorbital region is narrowest toward the front and shows weak beading at its margins; ''T. bolivaris'' is similar, but has stronger beading and ''H. megacephalus'' entirely lacks the beading.Musser et al., 1998, p. 174 The
parietal bone The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...
is usually limited to the roof of the braincase and does not extend to its side, as it does in most ''T. bolivaris''.Musser et al., 1998, p. 135 The
interparietal bone An interparietal bone (os interparietale or Inca bone or ''os inca var.'') is a dermal bone situated between the parietal and supraoccipital. It is homologous to the postparietal bones of other animals. In humans, it corresponds to the upper p ...
, part of the roof of the braincase, is large. The
incisive foramina In the human mouth, the incisive foramen (also known as: "''anterior palatine foramen''", or "''nasopalatine foramen''") is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood vesse ...
(openings in the front part of the
palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sepa ...
) are short and do not reach between the first molars; they are longer in ''H. alfaroi''. The bony palate is long and extends beyond the end of the molar row and the back margin of the
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
ry bones. The
posterolateral palatal pits In anatomy, posterolateral palatal pits are gaps at the sides of the back of the bony palate, near the last molars.Weksler, 2006, p. 34 Posterolateral palatal pits are present, in various degrees of development, in several members of the roden ...
, which perforate the palate near the third molars, are small, and may or may not be recessed into a fossa. The sphenopalatine vacuities (openings in the roof of the mesopterygoid fossa, behind the palate) are also small, as are the
auditory bulla The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic ...
e. As in most oryzomyines, the subsquamosal fenestra, an opening at the back of the skull, is present. The pattern of grooves and
foramina In anatomy and osteology, a foramen (;Entry "foramen"
in
(openings) in the skull indicates that the circulation of the arteries of the head in ''T. talamancae'' follows the primitive pattern, as in most similar species but unlike in ''
Hylaeamys ''Hylaeamys'' is a genus of South American oryzomyine rodents found principally in humid forested areas east of the Andes. The species in this genus have historically been placed in ''Oryzomys''. They are most closely related to ''Euryoryzomys'', ...
''. The
mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
(lower jaw) is less robust than in ''T. bolivaris''.Musser et al., 1998, p. 140 The coronoid process (a
process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...
in the back part of the bone) is small and the
capsular process In rodents, the capsular process or projection is a bony capsule that contains the root of the lower incisor. It is visible on the labial (outer) side of the mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest ...
, which houses the root of the lower
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...
, are small. The
mental foramen The mental foramen is one of two foramina (openings) located on the anterior surface of the mandible. It is part of the mandibular canal. It transmits the terminal branches of the inferior alveolar nerve and the mental vessels. Structure The m ...
, located in the
diastema A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...
between the lower
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...
and the first molar, opens towards the side, as usual in oryzomyines. The upper and lower masseteric ridges, which anchor some of the chewing muscles, do not join into a single crest and extend forward to below the first molar.Weksler, 2006, p. 42 The upper incisor is opisthodont, with the cutting edge oriented backward.Weksler, 2006, p. 43 As usual in oryzomyines, the molars are
brachydont The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
(low-crowned) and
bunodont The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
(with the cusps higher than the connecting crests). The first upper molar is narrower than in ''T. bolivaris''. In this species, but unlike in many other rice rats, including ''H. alfaroi'' and ''E. nitidus'', the mesoflexus on the second upper molar, which separates the
paracone A paracone is a 1960s atmospheric reentry or spaceflight mission abort concept using an inflatable ballistic cone.mesoloph Many different terms have been proposed for features of the tooth crown in mammals. The structures within the molars receive different names according to their position and morphology. This nomenclature was developed by Henry Fairfield Osborn i ...
(an accessory crest), is not divided in two by an enamel bridge. The hypoflexid on the second lower molar, the main valley between the cusps, is very long, extending more than halfway across the tooth; in this trait, the species is again similar to ''T. bolivaris'' but unlike ''H. alfaroi''. Each of the upper molars has three roots (two at the labial, or outer, side and one at the lingual, or inner, side) and each of the lower molars has two (one at the front and one at the back); ''T. talamancae'' lacks the additional small roots that are present in various other oryzomyines, including species of ''Euryoryzomys'', ''Nephelomys'', and ''Handleyomys''.


Male reproductive anatomy

As is characteristic of Sigmodontinae, ''Transandinomys talamancae'' has a complex penis, with the distal (far) end of the baculum (penis bone) ending in a structure consisting of three digits.Weksler, 2006, p. 55 As in most oryzomyines, the central digit is larger than the two at the sides. The outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue. Some features of the accessory glands in the male genital region vary among oryzomyines. In ''Transandinomys talamancae'', a single pair of
preputial gland Preputial glands are exocrine glands that are located in the folds of skin front of the genitals of some mammals. They occur in several species, including mice, ferrets, rhinoceroses, and even-toed ungulates and produce pheromones. The glands pla ...
s is present at the penis. As is usual for sigmodontines, there are two pairs of
ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
prostate The prostate is both an Male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, ...
glands and a single pair of
anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
and
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...
prostate glands. Part of the end of the vesicular gland is irregularly folded, not smooth as in most oryzomyines.


Karyotype

The
karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
in ''T. talamancae'' is variable. Samples from two different localities in Venezuela have 34 
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s and a
fundamental number A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
of 64 chromosomal arms (2n = 34, FN = 64).Musser et al., 1998, p. 163 Four specimens from another Venezuelan locality each have a different karyotype, with the number of chromosomes ranging from 40 to 42 and the fundamental number from 66 to perhaps 67. The
autosome An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in au ...
s (non-
sex chromosome A sex chromosome (also referred to as an allosome, heterotypical chromosome, gonosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical ...
s) of the 2n = 34 karyotype all have two major arms, but the 2n = 40–42 karyotypes include several
acrocentric The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers a ...
autosomes, which only have one major arm. The 2n = 34 karyotype includes two large
submetacentric The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers ...
pairs, which have two long arms but one distinctly longer than the other, and one pair of subtelocentric chromosomes, with a long and a much shorter arm, but the 2n = 40–42 karyotypes lack the submetacentrics and have another pair of subtelocentrics. Both
Robertsonian translocation Robertsonian translocation (ROB) is a chromosomal abnormality wherein a certain type of a chromosome becomes attached to another. It is the most common form of chromosomal translocation in humans, affecting 1 out of every 1,000 babies born. It doe ...
s (fusions of the long arm of one chromosome with the long arm of another and the short arm of the one with the short arm of the other) and pericentric inversions (reversals of part of a chromosome that includes the
centromere The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers a ...
) are needed to explain the difference between the two groups. Musser and colleagues, in discussing these karyotypes, assumed that the 2n = 40–42 sample was from within a
hybrid zone A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form ''in situ'' due to the evolution of a new lineage but generally they result from secondary contact ...
between two karyotypic morphs.Musser et al., 1998, p. 165 The karyotype of an Ecuadorean sample from north of the
Gulf of Guayaquil The Gulf of Guayaquil is a large body of water of the Pacific Ocean in western South America. Its northern limit is the city of Santa Elena, in Ecuador, and its southern limit is Cabo Blanco, in Peru. The gulf takes its name from the city of Gua ...
is similar to that of Venezuelan animals at 2n = 36, FN = 60; it includes four acrocentric and two subtelocentric pairs and no submetacentrics. In contrast, a sample from south of the Gulf had 2n = 54, FN = 60, including 23 pairs of acrocentrics and four pairs of metacentrics (with two equally long arms). Musser and colleagues termed the difference between the two Ecuadorian forms "impressive" and noted that further research was needed to understand the karyotypic differentiation within the species more fully. Both ''T. bolivaris'' and ''H. alfaroi'' have more chromosomes and arms, at 2n = 58, FN = 80 and 2n = 60–62, FN = 100–104 respectively. ''Hylaeamys megacephalus'' has 2n = 54, FN = 58–62 and the similar ''
Hylaeamys perenensis ''Hylaeamys perenensis'', formerly ''Oryzomys perenensis'', also known as the western Amazonian oryzomys, is an oryzomyine rodent of the family Cricetidae. It is found in western Amazonia (southeastern Colombia, eastern Ecuador, eastern Peru, ...
'' has 2n = 52, FN = 62; these karyotypes resemble that of southern Ecuadorean ''T. talamancae''.


Distribution and habitat

The distribution of ''Transandinomys talamancae'' extends from northwestern Costa Rica south and east to northern Venezuela and southwestern Ecuador, up to above sea level.Musser and Carleton, 2005, p. 1155 It is a forest species and occurs in both
evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...
and
deciduous forest In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
.Musser et al., 1998, p. 158 Although its distribution broadly overlaps that of ''T. bolivaris'', it is more widely distributed in South America because of its greater tolerance of dry forest habitats.Musser et al., 1998, p. 157 ''Transandinomys talamancae'' reaches the northern limit of its range in Costa Rica, but except for one record from the far northwest (in
Guanacaste Province Guanacaste () is a province of Costa Rica located in the northwestern region of the country, along the coast of the Pacific Ocean. It is bordered by Nicaragua to the north, Alajuela Province to the east, and Puntarenas Province to the southeast. I ...
near the southern margin of
Lake Nicaragua Lake Nicaragua or Cocibolca or Granada ( es, Lago de Nicaragua, , or ) is a freshwater lake in Nicaragua. Of tectonic origin and with an area of , it is the largest lake in Central America, the 19th largest lake in the world (by area) and the t ...
), it is known only from the southeastern third of the country. In contrast, ''T. bolivaris'' and ''H. alfaroi'' occur further north, into Honduras and Mexico respectively. It occurs throughout Panama at low elevations. Along the Pacific coast in Colombia and Ecuador, it is found on the coastal plain and the adjacent foothills of the Andes. The southernmost known record is in far southwestern Ecuador, but the species may range into nearby Peru. It also occurs throughout northern Colombia at low elevations and into western Venezuela west of
Lake Maracaibo Lake Maracaibo (Spanish: Lago de Maracaibo; Anu: Coquivacoa) is a lagoon in northwestern Venezuela, the largest lake in South America and one of the oldest on Earth, formed 36 million years ago in the Andes Mountains. The fault in the northern se ...
and at the foot of the western part of the
Venezuelan Coastal Range The Venezuelan Coastal Range ( es, Cordillera de la Costa or ), also known as Venezuelan Caribbean Mountain System ( es, Sistema Montañoso Caribe) is a mountain range system and one of the eight natural regions of Venezuela, that runs along the c ...
east to Guatopo National Park. ''Hylaeamys megacephalus'' occurs further to the east in the eastern portion of the coastal range, separated by the coastal Eastern Caribbean Dry Zone. There is a record from the
Orinoco Delta The Orinoco Delta is a vast river delta of the Orinoco River, located in eastern Venezuela. Location The Orinoco Delta is one of the eight natural regions of Venezuela. It covers the whole of Delta Amacuro State and a few square kilometers of M ...
of northeastern Venezuela, well within the range of ''Hylaeamys megacephalus'', but Musser and colleagues suggest that this is based on mislabeled specimens. The species has also been found on the narrow strip between the
Llanos The Llanos (Spanish ''Los Llanos'', "The Plains"; ) is a vast tropical grassland plain situated to the east of the Andes in Colombia and Venezuela, in northwestern South America. It is an ecoregion of the tropical and subtropical grasslands, sav ...
and the Andes ( Cordillera Oriental and
Cordillera de Mérida The Cordillera de Mérida is a series of mountain ranges, or massif, in northwestern Venezuela. The Cordillera de Mérida is a northeastern extension of the Andes Mountains and the most important branch of the Venezuelan Andes. The ranges run sou ...
) in eastern Colombia and northwestern Venezuela. The unforested Llanos separate these areas from ''Hylaeamys'' populations. ''
Hylaeamys perenensis ''Hylaeamys perenensis'', formerly ''Oryzomys perenensis'', also known as the western Amazonian oryzomys, is an oryzomyine rodent of the family Cricetidae. It is found in western Amazonia (southeastern Colombia, eastern Ecuador, eastern Peru, ...
'' does, however, occur further south along the eastern foothills of the Cordillera Oriental in Colombia and it is possible that the two overlap in this area.


Ecology and behavior

''Transandinomys talamancae'' is a common, even abundant, species. Its ecology was studied by Theodore Fleming in the
Panama Canal Zone The Panama Canal Zone ( es, Zona del Canal de Panamá), also simply known as the Canal Zone, was an unincorporated territory of the United States, located in the Isthmus of Panama, that existed from 1903 to 1979. It was located within the terr ...
. It lives on the ground and is active during the night.Fleming, 1971, p. 5 The animal nests above ground level and occasionally enters burrows also used by the pocket mouse '' Liomys adspersus''.Fleming, 1971, p. 60 Its diet is
omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...
: including both plant material such as seeds and fruits; and adult and larval insects. Males tend to travel longer distances than females. The average home range size in Fleming's study was 1.33 
hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is a ...
s (3.3 
acre The acre is a unit of land area used in the imperial Imperial is that which relates to an empire, emperor, or imperialism. Imperial or The Imperial may also refer to: Places United States * Imperial, California * Imperial, Missouri * Imp ...
s); males had larger home ranges on average.Fleming, 1971, p. 50 Specimens that were once captured tended to be captured more frequently than those that had never been captured.Fleming, 1971, p. 22 Fleming estimated that population densities reached peaks of up to 4.3 per ha (1.7 per acre) late in the rainy season (October–November), but dropped to near zero around June; however, these figures may well be underestimates. In central Venezuela, population densities vary from 5.5 to 9.6 per ha (2.2 to 3.8 per acre).Linares, 1998, p. 288 In Panama, this species breeds year-round without apparent seasonal variability.Fleming, 1971, p. 40 According to Omar Linares's ''Mamíferos de Venezuela'' (''Mammals of Venezuela''), reproductive activity is highest in June–July and December. In the laboratory, the
gestation period In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it ...
is 28 days;Fleming, 1971, p. 65 Linares reports 20 to 30 days in the wild. Females produce an average of six litters per year and there are two to five (average 3.92) young per litter, so that a single female may produce about 24 young per year; this is likely an overestimate because most females would not live for a full year. Larger females may have larger litters.Fleming, 1971, p. 41 Animals become sexually mature when less than two months old; in Fleming's study, some females in juvenile fur, probably less than 50 days old, were already pregnant.Fleming, 1971, p. 43 The oldest specimen Fleming observed was nine months old;Fleming, 1971, p. 29 he estimated that animals were unlikely to live for more than a year in the wildFleming, 1971, p. 32 and that the mean age at death was 2.9 months.Fleming, 1971, p. 48 Ten species of mites ('' Gigantolaelaps aitkeni'',Lee and Strandtmann, 1967, p. 30 '' Gigantolaelaps gilmorei'', '' Gigantolaelaps oudemansi'', '' Gigantolaelaps wolffsohni'', '' Haemolaelaps glasgowi'', '' Laelaps dearmasi'', '' Laelaps pilifer'', '' Laelaps thori'', '' Mysolaelaps parvispinosus'', and '' Paraspeleognathopsis cricetidarum''), thirteen chiggers ('' Aitkenius cunctatus'', '' Ascoschoengastia dyscrita'', ''
Eutrombicula alfreddugesi ''Eutrombicula'' is a genus of mites in the family Trombiculidae. The species of this genus are found throughout North America, and Australia. The genus was first described by Henry Ellsworth Ewing in 1938. Two genera of chigger mites, eac ...
'', '' Eutrombicula goeldii'', '' Intercutestrix tryssa'', '' Leptotrombidium panamensis'', '' Myxacarus oscillatus'', '' Pseudoschoengastia abditiva'', '' Pseudoschoengastia bulbifera'', '' Trombicula dunni'', and '' Trombicula keenani''), and four fleas ('' Jellisonia'' sp., '' Polygenis roberti'', '' Polygenis klagesi'', and '' Polygenis dunni'') have been found on ''T. talamancae'' in Panama. ''G. aitkeni'' has also been found on this species in Colombia. In addition, the sucking lice '' Hoplopleura nesoryzomydis'' and '' Hoplopleura oryzomydis'' occur on ''T. talamancae''.Durden and Musser, 1994, p. 30


Conservation status

A widespread and common species, ''Transandinomys talamancae'' is listed as "
Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
" by the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
. It occurs in numerous
protected area Protected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the ena ...
s, tolerates disturbed habitats well, and no important threats are known.


Notes


References


Literature cited

* Allen, J.A. 1891
Descriptions of two supposed new species of mice from Costa Rica and Mexico, with remarks on ''Hesperomys melanophrys'' of Coues
''Proceedings of the United States National Museum'' 14(850):193–196. * Allen, J.A. 1899
New rodents from Colombia and Venezuela
''Bulletin of the American Museum of Natural History'' 12:195–218. * Allen, J.A. 1908
Mammals from Nicaragua
''Bulletin of the American Museum of Natural History'' 24:647–670. * * Brennan, J.M. and Reed, J.T. 1973
The Neotropical genus ''Aitkenius'': Three New species and other records from Venezuela (Acarina: Trombiculidae)
(subscription required). ''The Journal of Parasitology'' 59(3):531–535. * Brennan, J.M. and Yunker, C.E. 1966
"The chiggers of Panama (Acarina: Trombiculidae)"
pp. 221–266 in Wenzel, R.L. and Tipton, V.J. (eds.). ''Ectoparasites of Panama''. Chicago: Field Museum of Natural History. * Clark, G.M. 1967
New Speleognathinae from Central and South American mammals (Acarina: Trombidiformes)
''Proceedings of the Helminthological Society of Washington'' 34:240–243. * Durden, L.A. and Musser, G.G. 1994
The sucking lice (Insecta, Anoplura) of the world: a taxonomic checklist with records of mammalian hosts and geographical distributions
''Bulletin of the American Museum of Natural History'' 218:1–90. * Fleming, T.H. 1970
Notes on the rodent faunas of two Panamanian forests
(subscription required). ''Journal of Mammalogy'' 51(3):473–490. * Fleming, T.H. 1971
Population ecology of three species of Neotropical rodents
''Miscellaneous Publications of the Museum of Zoology, University of Michigan'' 143:1–77. * Goldman, E.A. 1918
The rice rats of North America
''North American Fauna'' 43:1–100. * Handley, C.O., Jr. 1966
Checklist of the mammals of Panama
pp. 753–795 in Wenzel, R.L. and Tipton, V.J. (eds.). ''Ectoparasites of Panama''. Chicago: Field Museum of Natural History, xii + 861 pp. * Hershkovitz, P.M. 1960
Mammals of northern Colombia, preliminary report no. 8: Arboreal rice rats, a systematic revision of the subgenus ''Oecomys'', genus ''Oryzomys''
''Proceedings of the United States National Museum'' 110:513–568. * Lee, D. and Strandtmann, R.W. 1967
Two new species of ''Gigantolaelaps'' (Acarina: Laelaptidae) with a key to the females
(subscription required). ''Journal of the Kansas Entomological Society'' 40(1):25–32. * Linares, O.J. 1998. Mamíferos de Venezuela. Caracas: Sociedad Conservacionista Audubon de Venezuela and British Petroleum, 691 pp. (in Spanish). * * Musser, G.G. and Williams, M.M. 1985
Systematic studies of oryzomyine rodents (Muridae): Definitions of ''Oryzomys villosus'' and ''Oryzomys talamancae''
''American Museum Novitates'' 2810:1–22. * Musser, G.G., Carleton, M.D., Brothers, E.M. and Gardner, A.L. 1998
Systematic studies of oryzomyine rodents (Muridae: Sigmodontinae): diagnoses and distributions of species formerly assigned to ''Oryzomys "capito"''
''Bulletin of the American Museum of Natural History'' 236:1–376. * Patton, J.L., da Silva, M.N.F. and Malcolm, J.R. 2000
Mammals of the Rio Juruá and the evolutionary and ecological diversification of Amazonia
''Bulletin of the American Museum of Natural History'' 244:1–306. * Reid, F. 2009. ''A Field Guide to the Mammals of Central America and Southeast Mexico''. 2nd edition. Oxford University Press US, 346 pp. * Robinson, W. and Lyon, M.W., Jr. 1901
An annotated list of mammals collected in the vicinity of La Guaira, Venezuela
''Proceedings of the United States National Museum'' 24(1246):135–162. * Thomas, O. 1900
Descriptions of new Neotropical mammals
''Annals and Magazine of Natural History'' (7)5:269–274. * Thomas, O. 1901
New Neotropical mammals, with a note on the species of ''Reithrodon''
''Annals and Magazine of Natural History'' (7)8:246–255. * Tipton, V.J. and Méndez, E. 1966
The fleas (Siphonaptera) of Panama
pp. 289–385 in Wenzel, R.L. and Tipton, V.J. (eds.). ''Ectoparasites of Panama''. Chicago: Field Museum of Natural History. * Tipton, V.J., Altman, R.M. and Keenan, C.M. 1966
Mites of the subfamily Laelaptinae in Panama (Acarina: Laelaptidae)
pp. 23–82 in Wenzel, R.L. and Tipton, V.J. (eds.). ''Ectoparasites of Panama''. Chicago: Field Museum of Natural History. * Tirira, D. 2007. Guia de campo de los mamíferos del Ecuador. Quito: Ediciones Murciélago Blanco, publicación especial sobre los mamíferos del Ecuador 6, 576 pp. (in Spanish). * Weksler, M. 2006
"Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data"
''Bulletin of the American Museum of Natural History'' 296:1–149. * Weksler, M., Percequillo, A.R. and Voss, R.S. 2006
"Ten new genera of oryzomyine rodents (Cricetidae: Sigmodontinae)"
''American Museum Novitates'' 3537:1–29.


External links

* * {{Taxonbar, from=Q1763473 Mammals described in 1891 Mammals of Colombia Rodents of Central America Taxa named by Joel Asaph Allen Taxonomy articles created by Polbot Transandinomys Rodents of South America