White-faced spiny tree-rat

White-faced spiny tree-rat
A brown rat with a white stripe on its head on a log photographed from the front
In northeastern Brazil
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Placentalia
Order: Rodentia
Family: Echimyidae
Genus: Echimys
Species:
E. chrysurus
Binomial name
Echimys chrysurus
Map of South America with highlighted region over Guyana, Suriname, French Guiana, and parts of Brazil and Venezuela
White-faced spiny tree-rat range
Synonyms[3]
List
  • Myoxus chrysurus Zimmermann, 1780
  • Myoxus chrysourus; Zimmermann, 1783
  • Hystrix chrysuros; von Schreber, 1783
  • Myoxus chrysuros; Link, 1785
  • Glis chrysurus; Treviranus, 1803
  • Hystrix chrysoura; Goldfuss, 1809
  • Loncheres paleacea Illiger, 1811
  • Loncheres chrysura; Illiger, 1815
  • Echimys cristatus Desmarest, 1817

The white-faced spiny tree-rat (Echimys chrysurus) is a species of spiny rat from South America. It belongs to the spiny rat family, Echimyidae, and is one of three species in the genus Echimys, all of which are found in South America. The white-faced spiny tree-rat is restricted to forest and rainforest habitats in Brazil, French Guiana, Guyana and Suriname, living among the branches and feeding on fruit, plants, and insects. The rat's fur is darkest near the back of the head, which also has a distinctive white stripe. Its body is covered in stiff, blunt-tipped guard hairs or spines. Adults weigh up to 760 grams (27 ounces) and are 24 to 33 centimetres (9.4 to 13.0 inches) long, plus a tail that measures about 120% of the head-body length.

The white-faced spiny tree-rat is nocturnal and produces two young in a litter. Its known predators include the ornate hawk-eagle and spectacled owl. First recorded in 1778 and described in 1780, it is a rarely seen species; few studies on the rat's ecology have been performed, and there are not many museum specimens. However, because it is widespread and occurs in several protected areas, it is considered a least-concern species by the International Union for Conservation of Nature, though deforestation is a hazard to its survival.

Systematics and etymology

Illustration of black rat with white underbelly and partially yellow head and tail
18th-century engraving of the white-faced spiny tree-rat by Dutch draftsman Barent de Bakker, published in the work Histoire Naturelle

The white-faced spiny tree rat was first described by German zoologist Eberhard August Wilhelm von Zimmermann in 1780.[4] He drew upon the Swiss-Dutch natural philosopher Jean-Nicolas-Sébastien Allamand's 1778 addition to the Histoire Naturelle titled "Le Lérot à queue dorée",[a] a brief article containing a description and 13 measurements.[5][b] Zimmermann gave the species the scientific name of Myoxus chrysurus and wrote that its type locality was "Surinam" (at the time a Dutch colony[7]).[8] The original Histoire Naturelle article was based on the type specimen that was sent "without any information regarding either the name by which it is known in its country nor the places where it lives" to the private collector Jacob Christoph Klöckner in Amsterdam, who often wrote to Allamand about interesting new specimens. It is unknown what happened to the type specimen, though Klöckner's collection was auctioned off in 1783.[5]

Another species description of the white-faced spiny tree rat was written in 1817 by French zoologist Anselme Gaëtan Desmarest, who noted that the rodent's original description of "golden-tailed" may have stemmed from the solution it was preserved in, as a stuffed specimen used for comparison had no such yellow colour.[9] He gave it the scientific name of Echimys cristatus; this name was later regarded as a synonym of Echimys chrysurus.[3][10]

The taxonomy of the white-faced spiny tree rat changed often throughout the 18th and 19th centuries. Following its initial placement in Myoxus,[5][c] it was moved to Hystrix, the Old World porcupines. Later authors assigned it to Glis, Loncheres, and Nelomys[8] before the currently accepted name, Echimys chrysurus, was given by Swiss naturalist Heinrich Rudolf Schinz in his 1825 translation of Le Règne Animal.[12] The rodent is the type species of the genus Echimys,[10] as determined by zoologist George Henry Hamilton Tate in 1935.[13] The genus Echimys was created in 1809 by French naturalist Georges Cuvier to include both Myoxus chrysurus and one "rat épineux"[d] described in 1801, both of which were later clarified as belonging to the same species, E. chrysurus. This rat has no subspecies. The species Loncheres paleacea (Ignaz von Olfers, 1818) was once thought to represent a distinct species within Echimys and later a subspecies of the white-faced spiny tree-rat, under the trinomial Echimys chrysurus paleaceus, but following reexamination of the type specimen, it was regarded as a synonym of E. chrysurus.[6] According to genetic analysis, the species is closely related to the dark spiny tree-rat (Echimys saturnus). The following phylogenetic tree shows the relationships between the white-faced spiny tree-rat and its closest relatives, excluding Vieira's spiny tree-rat:[14]

Echimyidae

The species' binomial name derives from ancient Greek. The species name comes from χρυσός (khrusós), "gold", and οὐρά (ourá), "animal tail".[15][16] The genus name Echimys, and also its synonym Echinomys,[17] derive from ἐχῖνος (ekhînos), meaning "hedgehog", and μῦς (mûs), meaning "mouse, rat".[15][16]

Distribution and habitat

The white-faced spiny tree-rat lives throughout Guyana, Suriname, French Guiana, and parts of Brazil.[1] In Brazil, it is known from the eastern Amazon Basin throughout Amapá and parts of Amazonas; east of the Rio Negro in parts north of the Amazon River, and east of the Xingu River south of the Amazon.[6] It is uncertain if this rat is present in parts of Bolívar, Venezuela.[18] Within French Guiana, specimens have only been identified in four locations.[19]

Vine-covered areas of lowland rainforests are the preferred habitat of the white-faced spiny tree-rat. It is a strictly arboreal (tree-dwelling) species; it resides in the middle and upper strata of the rainforest at elevations ranging from sea level up to about 200 metres (660 feet).[8] Though most sightings of the rat have been in tropical evergreen forests, it is known to live in regions where rainforest transitions to deciduous forest as well.[20]

Description

A brown and white rat on a log
The rodent as seen from the side, its white-tipped tail fully visible

White-faced spiny tree-rats typically weigh up to 760 grams (27 ounces) and have a length of 24 to 33 centimetres (9.4 to 13.0 inches) from the head to the base of the tail. The tail ranges in length from 25 to 40 cm (9.8 to 15.7 in), typically measuring 120% of the rodent's total head and body length, and is covered in hair that turns from brown to white towards the tip.[8]

The rat's fur is made up of a mixture of broad, heavy spines and dark hairs that are brown at the tip and grey along the shaft.[21] The fur near the back of the head is darker than that along the rest of the animal's body.[8] The ears are small, slightly haired, and brown. Its eyes are dark brown and have a red eye shine. The broad feet are covered with brown fur on top, and each digit has a claw.[8] Females have three pairs of developed abdominal mammary glands between the front and hind legs, as well as one pair of small, possibly non-functional mammary glands in the groin region.[10]

Among members of the Echimyidae family, the genus Echimys has some of the most spinose guard hairs or spines, meaning that they are very stiff and robust and have blunt tips. The purpose of these hairs and differences within the family in terms of guard hair softness is thought to be tied to ancestral habitat preference and need for temperature regulation, as softer, denser fur is better at holding on to warmth.[22]

The white-faced spiny tree-rat has several external features that serve as diagnostic character states or traits. The main trait unique to this species is a white stripe on the head that extends from the muzzle back to between the ears.[10] As compared to Vieira's spiny tree-rat and the dark spiny tree-rat, the fur on the back of the white-faced spiny tree-rat is brighter.[13]

The species may also be distinguished from other members of Echimys by several characteristics of its skull: its auditory bullae, bony structures that contain the inner ear, are of medium to small size, the external auditory meatus or ear canal is short, and it has a small internal auditory meatus, a bony canal connecting the inner ear to a cavity at the back of the skull (the posterior cranial fossa). The convex surface of the lower back of the skull, the squamous part of the occiptial bone, has short bony extensions on the lateral sides of the foramen magnum, an opening at the skull's back and lower part (the occiput). Nearby, the depression in the base of the skull known as the jugular fossa is broad and deep. Small, nearly circular openings or fenestrae are present ahead of (anterior to) the ear canals. The septum of the premaxillary bone, at the very tip of the upper jaw, is incompletely separated towards the back. The white-faced spiny tree-rat has parallel, rectangular rows of teeth, and its cheek teeth are longer than they are wide. The species' lower molars are very similar to those in other tree-dwelling spiny rats.[8] However, the alveolar length of the rodent's upper cheek teeth (between 13.3 and 14.5 millimetres (0.52 and 0.57 inches)) has been used as a diagnostic trait, as this length is greater than that of any other member of Echimyidae found in Suriname.[10]

Behaviour and ecology

An owl on a branch seen from below in the dark
A spectacled owl in Guyana, a predator of the white-faced spiny tree-rat

White-faced spiny tree-rats are nocturnal animals.[1] One female specimen was discovered carrying two embryos,[8] which is a typical number of young per litter for members of the spiny rat family Echimyidae;[23] the young are born already covered in fur and have their eyes open.[24] The species typically has a slow pace of movement, but may move quickly across branches when startled by human or predator activity.[8] They have been observed creeping under foliage and remaining motionless for minutes at a time when disturbed, and are known to make nests in tree holes, using leaves as nesting material.[6] The species feeds on fruit, foliage, and some insects, mainly arthropods.[8]

The ornate hawk-eagle and the spectacled owl are known predators of the white-faced spiny tree-rat.[25][10] Terrestrial mammals within the rodent's range that may prey upon it include ocelots and the common opossum.[26] The white-faced spiny tree-rat is host to several parasites, including several members of the flea genus Polygenis[27] and the sandfly species Bichromomyia flaviscutellata.[28] This sandfly is the main vector for the spread of Leishmania amazonensis, a parasite that causes leishmaniasis, throughout the Brazilian Amazon.[29] Rhodnius paraensis, a species of kissing bug discovered in 1977, also feeds upon the blood of this rodent.[30]

Conservation

The white-faced spiny tree-rat has a stable population trend. It is potentially threatened by deforestation, though the 2016 report produced by Catzeflis and Patton for the International Union for Conservation of Nature (IUCN) did not consider this to be a major issue. They classified the species as least concern due to its wide distribution and presence in several protected areas.[1] It was previously classified as vulnerable in the 1996 issue of the IUCN Red List due to a perceived population decline caused by loss of habitat and threats by introduced species in Brazil.[31] Few museum specimens and ecological studies of the species exist,[8] and it has generally been thought of as a rare species, being infrequently mentioned in literature.[10]

Notes

  1. ↑ "The golden-tailed garden dormouse"
  2. ↑ While Allamand's article first described the species, Zimmermann published his description with a scientific name, making him the species authority.[6]
  3. ↑ The genus Myoxus later became a synonym of Glis.[11]
  4. ↑ "spiny mouse"

References

  1. 1 2 3 4 Catzeflis, F.; Patton, J. (2016). "Echimys chrysurus". IUCN Red List of Threatened Species. 2016 e.T6979A22207079. doi:10.2305/IUCN.UK.2016-2.RLTS.T6979A22207079.en. Retrieved 20 April 2026.
  2. ↑ "Echimys chrysurus (Zimmermann, 1780)". Global Biodiversity Information Facility. Retrieved 10 March 2025.
  3. 1 2 "Echimys chrysurus (Zimmermann, 1780)". ASM Mammal Diversity Database. American Society of Mammalogists. Retrieved 31 December 2025.
  4. ↑ Woods, C.A.; Kilpatrick, C.W. (2005). "Species Echimys chrysurus". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 1578. ISBN 978-0-8018-8221-0. OCLC 62265494.
  5. 1 2 3 Rookmaaker, L. C. (1992). "J.N.S. Allamand's additions (1769—1781) to the Nouvelle Edition of Buffon's Histoire Naturelle published in Holland". Bijdragen tot de Dierkunde. 61 (3): 131–162. doi:10.1163/26660644-06103001.
  6. 1 2 3 4 Emmons, L.H.; Leite, Y.L.R.; Patton, J.L. (2015). "Genus Echimys F. Cuvier, 1809". In Patton, J.L.; Pardiñas, U.F.J.; D'Elía, G. (eds.). Mammals of South America. Vol. 2: Rodents. University of Chicago Press. pp. 893–898.
  7. ↑ Boxer, Charles Ralph (1973). The Dutch Seaborne Empire, 1600-1800. Penguin Books. pp. 270–272.
  8. 1 2 3 4 5 6 7 8 9 10 11 Fabre, Pierre-Henri; Patton, Jim; Leite, Yuri (2016). "Family Echimyidae (Hutias, Coypu and South American Spiny-rats)". In Wilson, D.E.; Lacher, T.E.; Mittermeier, R.A. (eds.). Handbook of the Mammals of the World. Vol. 6. Lagomorphs and Rodents I. Lynx Edicions. p. 633. ISBN 978-84-941892-3-4.
  9. ↑ Desmarest, Anselme Gaëtan (1817). Nouveau dictionnaire d'histoire naturelle, appliquée aux arts, à l'agriculture, à l'économie rurale et domestique, à la médecine, etc [New Dictionary of Natural History, Applied to the Arts, Agriculture, the Rural and Domestic Economy, and Medicine, etc] (in French). p. 54. doi:10.5962/bhl.title.20211 – via Biodiversity Heritage Library.
  10. 1 2 3 4 5 6 7 Husson, A.M. (1978). "The Mammals of Suriname". Zoölogische Monographieën. 2: 373, 378, 440–444 – via Naturalis Biodiversity Center.
  11. ↑ Kryštufek, Boris (2010). "Glis glis (Rodentia: Gliridae)" (PDF). Mammalian Species. 42 (865): 195–206. doi:10.1644/865.1. Retrieved 4 August 2026.
  12. ↑ Cuvier, Georges; Schinz, Heinrich Rudolf (1825). Das Thierreich eingetheilt nach dem Bau der Thiere als Grundlage ihrer Naturgeschichte und der vergleichenden Anatomie (in German). Vol. 4. Zoophyten. p. 387. doi:10.5962/bhl.title.115394 – via Biodiversity Heritage Library.
  13. 1 2 Iack-Ximenes, Gilson Evaristo; de Vivo, Mario; Percequillo, Alexandre Reis (2005). "A new species of Echimys Cuvier, 1809 (Rodentia, Echimyidae) from Brazil". Papéis Avulsos de Zoologia. 45 (5): 51–60. doi:10.1590/S0031-10492005000500001. ISSN 0031-1049.
  14. ↑ Emmons, Louise H.; Fabre, Pierre-henri (9 March 2018). "A review of the Pattonomys/Toromys clade (Rodentia: Echimyidae), with descriptions of a new Toromys species and a new genus". American Museum Novitates (3894): 1–52. doi:10.1206/3894.1. ISSN 0003-0082.
  15. 1 2 Bailly, Anatole (1 January 1981). Abrégé du dictionnaire grec français. Hachette. pp. 874, 1308, 1424, 2160. ISBN 2-01-003528-3. OCLC 461974285.
  16. 1 2 Bailly, Anatole. "Greek-french dictionary online". Tabularium. Archived from the original on 18 March 2022. Retrieved 5 November 2017.
  17. ↑ Wagner, Johann Andreas (1840). "Beschreibung einiger neuer Nager, welche auf der Reise des Herrn Hofraths v. Schubert gesammelt wurden: mit Bezugnahme auf einige andere verwandte Formen". Abhandlungen der Mathematisch-Physikalischen Classe der Königlich Bayerischen Akademie der Wissenschaften (in German). pp. 191–210.
  18. ↑ Catzeflis, F.; Patton, J. (2008). "Echimys chrysurus". IUCN Red List of Threatened Species. 2008 e.T6979A12819331. doi:10.2305/IUCN.UK.2008.RLTS.T6979A12819331.en. Retrieved 15 July 2026.
  19. ↑ Voss, Robert S.; Lunde, Darrin P.; Simmons, Nancy B. (2001). "The mammals of Paracou, French Guiana, a neotropical lowland. Rainforest fauna, part 2, nonvolant species". Bulletin of the American Museum of Natural History (263): 234. hdl:2246/386. ISSN 0003-0090.
  20. ↑ Oliveira, Tadeu; Mesquita, E.R.L. (1998). "Notes on the distribution of the white-faced tree rat, Echimys chrysurus (Rodentia, Echimyidae) in northeastern Brazil". Mammalia. 62 (2): 305–306.
  21. ↑ Garst, Warren (October 1965), "White-faced tree rat standing on log", Garst (Warren and Genevieve) Collection, hdl:10217/54390 – via Digital Public Library of America
  22. ↑ Fabre, P.-H.; Patton, J. L.; Leite, Y. L. R. (2016). "Family Echimyidae". In Wilson, D.E.; Lacher, T.E.; Mittermeier, R.A. (eds.). Handbook of the Mammals of the World. Vol. 6. Lagomorphs and Rodents I. Lynx Edicions. pp. 563–565. ISBN 978-84-941892-3-4.
  23. ↑ Silva, Marielle Portugal Lamberti; Leite, Yuri Luiz Reis; Costa, Leonora Pires (2015). "Litter size and embryo implantation in Neotropical rodents". Oecologia Australis (in Portuguese). 19. doi:10.4257/oeco.2015.1901.12. ISSN 2177-6199.
  24. ↑ Eisenberg, John Frederick (1989). Mammals of the Neotropics. Vol. 1. University of Chicago Press. p. 409. ISBN 0-226-19539-2.
  25. ↑ Silva, Diego Afonso; Calaça, Analice Maria; Alencar, Raony Macedo; Faria, Michel Barros; Melo, Fabiano Rodrigues de (17 December 2024). "Predation of a rare white-faced tree rat Echimys chrysurus by the ornate hawk-eagle Spizaetus ornatus in a lowland Amazonian rainforest". Brazilian Journal of Mammalogy (93): e932024153. doi:10.32673/bjm.vi93.153. ISSN 2764-0590.
  26. ↑ Palmeirim, Ana Filipa; Benchimol, Maíra; Vieira, Marcus V.; Peres, Carlos A. (1 May 2024). "Disentangling the effects of habitat fragmentation and top-down trophic cascades on small mammal assemblages on Amazonian forest islands". Biological Conservation. 293 110594. doi:10.1016/j.biocon.2024.110594. ISSN 0006-3207.
  27. ↑ Pesenato, Isabella Pereira; de Oliveira Jorge Costa, Jaciara; de Castro Jacinavicius, Fernando; Bassini-Silva, Ricardo; Soares, Herbert Sousa; Fakelmann, Thiago; Castelli, Giovanna Nosberto; Maia, Gledson Bandeira; Onofrio, Valeria Castilho; Nieri-Bastos, Fernanda Aparecida; Marcili, Arlei (4 April 2025). "Brazilian fleas (Hexapoda: Siphonaptera): diversity, host associations, and new records on small mammals from the Atlantic Rainforest, including Rickettsia screening". Parasites & Vectors. 18 (1): 130. doi:10.1186/s13071-025-06755-6. ISSN 1756-3305. PMC 11969852. PMID 40181440.
  28. ↑ Kocher, Arthur; de Thoisy, Benoit; Catzeflis, François; Valière, Sophie; Bañuls, Anne‐Laure; Murienne, Jérôme (2017). "iDNA screening: Disease vectors as vertebrate samplers". Molecular Ecology. 26 (22): 6478–6486. doi:10.1111/mec.14362. ISSN 0962-1083.
  29. ↑ de Melo, Leonardo Barroso; Scarpassa, Vera Margarete (1 January 2024). "Phylogeographic inference for Bichromomyia flaviscutellata sensu stricto (Diptera: Psychodidae: Phebotominae) from the Brazilian Amazon rainforest, based on the 3ʹ region of the COI gene". Journal of Medical Entomology. 61 (1): 142–151. doi:10.1093/jme/tjad125. ISSN 0022-2585.
  30. ↑ Miles, M. A.; Llewellyn, M. S.; Lewis, M. D.; Yeo, M.; Baleela, R.; Fitzpatrick, S.; Gaunt, M. W.; Mauricio, I. L. (2009). "The molecular epidemiology and phylogeography of Trypanosoma cruzi and parallel research on Leishmania : looking back and to the future". Parasitology. 136 (12): 1509–1528. doi:10.1017/S0031182009990977. ISSN 0031-1820.
  31. ↑ Baillie, Jonathan; Groombridge, Brian, eds. (1996). 1996 IUCN Red List of Threatened Animals (PDF). International Union for Conservation of Nature and Natural Resources. p. 28. ISBN 2-8317-0335-2.
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