Armored rat

Adults weigh between {{convert|218|-|790|g|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 {{convert|33|mm|in}} and {{convert|2|mm|in}} in diameter. The head and body measures between {{convert|220|-|320|mm|in}} in length, with the tail adding another {{convert|150|-|255|mm|in}}.{{cite book|last=Nowak|first=Ronald M|title=Walker's Mammals of the World|year=1999|page=1689|publisher=Johns Hopkins University Press|location=Baltimore|isbn=978-0-8018-5789-8|url=https://books.google.com/books?id=7W-DGRILSBoC&q=%22armored+rat%22&pg=PA1689}} The color of the armored rat range from black to reddish brown, and has a pure white underside. They are similar in appearance to Tome's spiny-rat, but the eyes of the armored rat are smaller and they have a longer snout. Its diet includes fruit, insects and green plant matter. The normal litter size is one to three.

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 {{convert|2|m|ft}} in length before reaching an enlarged nesting chamber.{{cite book|last=Reid|first=Fiona|title=A Field Guide to the Mammals of Central America & Southeast Mexico|year=1997|publisher=Oxford University Press|location=New York|pages=251–252|url=https://books.google.com/books?id=aBEbUaXTWYAC&q=%22armored+rat%22&pg=PA251|isbn=9780195343229}} The armored rat covers its nesting chamber with vegetation and keeps it dry. It uses a separate chamber for defecating.{{Cite web |last=Cusick |first=Patrick |title=Hoplomys gymnurus (armored rat) |url=https://animaldiversity.org/accounts/Hoplomys_gymnurus/ |access-date=2025-04-21 |website=Animal Diversity Web |language=en}}

This species is distributed from northern Honduras to northwest Ecuador, from lowlands up to around {{convert|800|m|ft}} in altitude, including Panama's isolated Caribbean island of Isla Escudo de Veraguas.{{Cite journal|last= Handley|first= C.O.|author-link= Charles O. Handley|hdl= 10088/22959|title=A review of the genus Hoplomys (thick-spined rats), with description of a new form from Isla Escudo de Veraguas, Panama|year= 1959|journal= Smithsonian Miscellaneous Collections|volume= 139|number= 4|pages= 1–10|publisher= Smithsonian Institution|oclc= 906190284}}

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.

The armored rat is considered a seed disperser for the palm Attalea 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 of iguanid lizard eggs.

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 three precocial pups (born without spiny fur). The young are sheltered in the 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.

• The genus name Hoplomys derives from the two Ancient Greek words {{wikt-lang|grc|ὅπλον}} ({{grc-transl|ὅπλον}}), meaning "armor", and {{wikt-lang|grc|μῦς}} ({{grc-transl|μῦς}}), meaning "rat".{{Cite book|title=Abrégé du dictionnaire grec français|last=Bailly|first=Anatole|date=1981-01-01|publisher=Hachette|isbn=978-2010035289|location=Paris|oclc=461974285}}{{Cite web|url=http://www.tabularium.be/bailly/|title=Greek-french dictionary online|last=Bailly|first=Anatole|website=www.tabularium.be|access-date=2017-01-24}}
• The species name gymnurus derives from the two Ancient Greek words {{wikt-lang|grc|γυμνός}} ({{grc-transl|γυμνός}}), meaning "naked", and {{wikt-lang|grc|οὐρά}} ({{grc-transl|οὐρά}}), meaning "tail".

Part of the infraorder Hystricognathi and family Echimyidae, armored rats are more closely related to porcupines, Guinea pigs, chinchillas, and common degus than to the common brown rat.{{Cite journal|last1=Huchon|first1=Dorothée|last2=Douzery|first2=Emmanuel J.P.|title=From the Old World to the New World: A Molecular Chronicle of the Phylogeny and Biogeography of Hystricognath Rodents|journal=Molecular Phylogenetics and Evolution|volume=20|issue=2|pages=238–251|doi=10.1006/mpev.2001.0961|pmid=11476632|year=2001}}{{cite book|last=Reid|first=Fiona|title=The Wildlife of Costa Rica|year=2010|publisher=Comstock Pub. Associates|location=Ithaca, N.Y.|isbn=978-0-8014-7610-5|pages=17|url=https://books.google.com/books?id=ZXOzzYoYkGUC&q=%22armored+rat%22&pg=PA17}}

Within Echimyidae, the genus Hoplomys is the sister group to the genus Proechimys. In turn, these two taxa share evolutionary affinities with other Myocastorini genera: Callistomys (painted tree-rats) and Myocastor (coypus or nutrias) on the one hand, and Thrichomys on the other hand.

{{cladogram

|title=Genus-level cladogram of the Myocastorini.

|caption=The cladogram has been reconstructed from mitochondrial and nuclear DNA characters.{{Cite journal|last1=Galewski|first1=Thomas|last2=Mauffrey|first2=Jean-François|last3=Leite|first3=Yuri L. R.|last4=Patton|first4=James L.|last5=Douzery|first5=Emmanuel J. P.|year=2005|title=Ecomorphological diversification among South American spiny rats (Rodentia; Echimyidae): a phylogenetic and chronological approach|journal=Molecular Phylogenetics and Evolution|volume=34|issue=3|pages=601–615|doi=10.1016/j.ympev.2004.11.015|pmid=15683932}}{{Cite journal|last1=Upham|first1=Nathan S.|last2=Patterson|first2=Bruce D.|year=2012|title=Diversification and biogeography of the Neotropical caviomorph lineage Octodontoidea (Rodentia: Hystricognathi)|journal=Molecular Phylogenetics and Evolution|volume=63|issue=2|pages=417–429|doi=10.1016/j.ympev.2012.01.020|pmid=22327013}}{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Galewski|first2=Thomas|last3=Tilak|first3=Marie-ka|last4=Douzery|first4=Emmanuel J. P.|date=2013-03-01|title=Diversification of South American spiny rats (Echimyidae): a multigene phylogenetic approach|journal=Zoologica Scripta|language=en|volume=42|issue=2|pages=117–134|doi=10.1111/j.1463-6409.2012.00572.x|s2cid=83639441|issn=1463-6409}}{{Cite journal|last1=Loss|first1=Ana|last2=Moura|first2=Raquel T.|last3=Leite|first3=Yuri L. R.|date=2014|title=Unexpected phylogenetic relationships of the painted tree rat Callistomys pictus (Rodentia: Echimyidae)|url=http://www.naturezaonline.com.br/natureza/conteudo/pdf/05_LossACetal_132-136.pdf|journal=Natureza on Line|volume=12|pages=132–136}}{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Vilstrup|first2=Julia T.|last3=Raghavan|first3=Maanasa|last4=Der Sarkissian|first4=Clio|last5=Willerslev|first5=Eske|last6=Douzery|first6=Emmanuel J. P.|last7=Orlando|first7=Ludovic|date=2014-07-01|title=Rodents of the Caribbean: origin and diversification of hutias unravelled by next-generation museomics|journal=Biology Letters|language=en|volume=10|issue=7|pages=20140266|doi=10.1098/rsbl.2014.0266|pmid=25115033|issn=1744-9561|pmc=4126619}}{{Cite book|title=Biology of caviomorph rodents: diversity and evolution|last1=Upham|first1=Nathan S.|last2=Patterson|first2=Bruce D.|publisher=SAREM Series A, Mammalogical Research — Sociedad Argentina para el Estudio de los Mamíferos|year=2015|editor-last1=Vassallo|editor-first1=Aldo Ivan|location=Buenos Aires|pages=63–120|chapter=Evolution of Caviomorph rodents: a complete phylogeny and timetree for living genera|editor-last2=Antenucci|editor-first2=Daniel}}{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Upham|first2=Nathan S.|last3=Emmons|first3=Louise H.|last4=Justy|first4=Fabienne|last5=Leite|first5=Yuri L. R.|last6=Loss|first6=Ana Carolina|last7=Orlando|first7=Ludovic|last8=Tilak|first8=Marie-Ka|last9=Patterson|first9=Bruce D.|last10=Douzery|first10=Emmanuel J. P.|date=2017-03-01|title=Mitogenomic Phylogeny, Diversification, and Biogeography of South American Spiny Rats|journal=Molecular Biology and Evolution|volume=34|issue=3|pages=613–633|doi=10.1093/molbev/msw261|pmid=28025278|issn=0737-4038|doi-access=free}}

|align=center

|clades={{Cladogram of Myocastorini genera}}

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;Specific

{{Reflist|2}}

;General

{{Refbegin}}

• Woods, C. A. and C. W. Kilpatrick. 2005. Hystricognathi. pp 1538–1600 in 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.

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{{Commons category|Hoplomys gymnurus}}

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Category:Myocastorini

Category:Mammals of Colombia

Category:Mammals of Ecuador

Category:Mammals described in 1897

Category:Taxa named by Oldfield Thomas

Category:Rodents of Central America

Category:Rodents of South America

Category:Taxonomy articles created by Polbot