Thearmored rat (Hoplomys gymnurus) is a species ofrodent in the familyEchimyidae. It ismonotypic within thegenusHoplomys.[2] It is found inLatin America, from northernHonduras to northwestEcuador. It possesses a range of spines on its back and sides of the body.[3]
Adults weigh between 218–790 grams (0.481–1.742 lb) with males weighing more on average than females.They are born with soft fur, and the spines begin growing after the first month. The thick spines on the back and sides measure up to 33 millimetres (1.3 in) and 2 millimetres (0.079 in) in diameter.[4] The head and body measures between 220–320 millimetres (8.7–12.6 in) in length, with the tail adding another 150–255 millimetres (5.9–10.0 in).[4] The color of the armored rat range from black to reddish brown, and has a pure white underside. They are similar in appearance toTome's spiny-rat, but the eyes of the armored rat are smaller and they have a longersnout.[3] Its diet includes fruit, insects and green plant matter. The normal litter size is one to three.[3]
The armored rat is a terrestrial species, which occupies burrows. These burrows are usually positioned in steep banks close to a water source, and can measure up to 2 metres (6.6 ft) in length before reaching an enlarged nesting chamber.[3] The armored rat covers its nesting chamber with vegetation and keeps it dry. It uses a separate chamber for defecating.[5]
This species is distributed from northernHonduras to northwestEcuador, from lowlands up to around 800 metres (2,600 ft) in altitude,[3] including Panama's isolated Caribbean island ofIsla Escudo de Veraguas.[6]
The armored rat is nocturnal, spending most of its day inside its burrow and coming out at night to forage for food. It primarily eats fruits like bananas, wild figs, avocados, and mangoes, but it will also hunt insects like beetles and grasshoppers. It exhibits caching behaviour, bringing back some food to its burrow.[5]
The armored rat is considered a seed disperser for the palmAttalea butyraceae, as well as an ecosystem engineer, with its many pathways and burrows creating microhabitats for smaller organisms and nests for other animals—with one armored rat burrow found to contain an extra cavity full ofiguanid lizard eggs.[5]
While some armoured rats breed year-round, others will time their breeding to coincide with the rain. Pregnant females have been found from February to July. After 64 days of gestation, they give birth to a litter of one to threeprecocial pups (born without spiny fur). The young are sheltered in their mother's burrow and fed for some three to four weeks. By the time they're weaned off her milk, their fur has already begun to develop into spines. Armored rats mature at around 5 months of age.[5]
Within Echimyidae, the genusHoplomys is the sister group to the genusProechimys. In turn, these two taxa share evolutionary affinities with otherMyocastorini genera:Callistomys (painted tree-rats) andMyocastor (coypus or nutrias) on the one hand, andThrichomys on the other hand.
^Handley, C.O. (1959). "A review of the genusHoplomys (thick-spined rats), with description of a new form from Isla Escudo de Veraguas, Panama".Smithsonian Miscellaneous Collections.139 (4). Smithsonian Institution:1–10.hdl:10088/22959.OCLC906190284.
^Huchon, Dorothée; Douzery, Emmanuel J.P. (2001). "From the Old World to the New World: A Molecular Chronicle of the Phylogeny and Biogeography of Hystricognath Rodents".Molecular Phylogenetics and Evolution.20 (2):238–251.Bibcode:2001MolPE..20..238H.doi:10.1006/mpev.2001.0961.PMID11476632.
^Galewski, Thomas; Mauffrey, Jean-François; Leite, Yuri L. R.; Patton, James L.; Douzery, Emmanuel J. P. (2005). "Ecomorphological diversification among South American spiny rats (Rodentia; Echimyidae): a phylogenetic and chronological approach".Molecular Phylogenetics and Evolution.34 (3):601–615.Bibcode:2005MolPE..34..601G.doi:10.1016/j.ympev.2004.11.015.PMID15683932.
^Upham, Nathan S.; Patterson, Bruce D. (2012). "Diversification and biogeography of the Neotropical caviomorph lineage Octodontoidea (Rodentia: Hystricognathi)".Molecular Phylogenetics and Evolution.63 (2):417–429.Bibcode:2012MolPE..63..417U.doi:10.1016/j.ympev.2012.01.020.PMID22327013.
^Fabre, Pierre-Henri; Galewski, Thomas; Tilak, Marie-ka; Douzery, Emmanuel J. P. (2013-03-01). "Diversification of South American spiny rats (Echimyidae): a multigene phylogenetic approach".Zoologica Scripta.42 (2):117–134.doi:10.1111/j.1463-6409.2012.00572.x.ISSN1463-6409.S2CID83639441.
^Upham, Nathan S.; Patterson, Bruce D. (2015). "Evolution of Caviomorph rodents: a complete phylogeny and timetree for living genera". In Vassallo, Aldo Ivan; Antenucci, Daniel (eds.).Biology of caviomorph rodents: diversity and evolution. Buenos Aires: SAREM Series A, Mammalogical Research — Sociedad Argentina para el Estudio de los Mamíferos. pp. 63–120.
Woods, C. A. and C. W. Kilpatrick. 2005. Hystricognathi. pp 1538–1600in Mammal Species of the World a Taxonomic and Geographic Reference 3rd ed. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.
