Ihering's Atlantic spiny rat

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Ihering's Atlantic spiny-rat
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Echimyidae
Subfamily: Euryzygomatomyinae
Genus: Trinomys
Species:
T. iheringi
Binomial name
Trinomys iheringi
(Thomas, 1911)
Synonyms

Proechimys iheringi

Ihering's Atlantic spiny-rat[2] or Ihering's spiny rat[1] (Trinomys iheringi) is a spiny rat species from Brazil.[2][1]

Taxonomy

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It was first described by Oldfield Thomas in 1911, who placed it in Proechimys. It was named in honor of Hermann von Ihering, who collected the type specimen.[3]

In 1948, João Moojen described six subspecies (bonafidei, denigratus, gratiosus, iheringi, panema, and paratus), though he was unhappy with his population sample and expected some of them may have been properly full species based on geographic isolation and physical differences.[4][5] A seventh (eliasi) was described in 1992 by Reis et al.[6] In 2000, Proechimys iheringi was moved to Trinomys by Lara and Patton, who also reclassified the former subspecies based on genetic analysis.[2][6] Trinomys eliasi and T. paratus became separate species, as did T. gratiosus with bonafidei as a subspecies. dengiratus became a subspecies of T. setosus. The study was unable to examine any specimens of panema.[4] As of 2025, the species has no named subspecies.[6][7]

A 2016 analysis based on phenotypic traits found that it was most closely related to T. dimidatus, from which it diverged an estimated 6.5 million years ago.[8]

Description

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Trinomys iheringi is a medium-sized rat, with an average head and body length of 191 millimetres (7.5 in) with a 171 millimetres (6.7 in) tail. They weigh about 209 grams (7.4 oz). The fur on the top of the body is "cinnamon-buff", which lightens to white on the stomach. The tail has a brown base and white tip.[6] Like other spiny rats, the coat is mixed with long stiff furs, or spines, about 21 millimetres (0.83 in) in length along the back.[3]

T. iheringi has 30 pairs of standard chromosomes, as well as a variable number of additional "dot-like"[9] supernumerary chromosomes.[10][11]

It is found in Atlantic rainforest in Brazil, near the coasts, in the states of Sao Paulo and Rio de Janeiro.[7][9] The Rio de Janeiro population, located on the island of Ilha Grande, is genetically distinct, and may represent a separate species.[7] The two populations diverged about 0.6 million years ago, possibly due to glacial cycling occurring at the time.[12]

They have unusually large home ranges for rodents of their size, an average of 1.37 hectares (13,700 m2) for males and 0.86 hectares (8,600 m2) for females.[2] The females reach full maturity at approximately eight months, and the lifespan is up to 30 months.[2] They can reproduce year-round, but more commonly do so during the rainy season. They are likely polygynous.[6]

It is listed by the IUCN as a species of least concern due to its wide distribution and large population.[2]

References

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  1. ^ a b c Patterson, B. (2016). "Trinomys iheringi". IUCN Red List of Threatened Species. 2016: e.T18288A22212466. doi:10.2305/IUCN.UK.2016-2.RLTS.T18288A22212466.en. Retrieved 19 August 2021.
  2. ^ a b c d e f Woods, C.A.; Kilpatrick, C.W. (2005). "Infraorder Hystricognathi". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 1538–1600. ISBN 978-0-8018-8221-0. OCLC 62265494.
  3. ^ a b Thomas, Oldfield (1911-08-01). "XXVII.—New rodents from S. America". Annals and Magazine of Natural History. 8 (44): 250–256. doi:10.1080/00222931108693019.
  4. ^ a b LARA, MARCIA C.; PATTON, JAMES L. (2000-12-01). "Evolutionary diversification of spiny rats (genus Trinomys, Rodentia: Echimyidae) in the Atlantic Forest of Brazil". Zoological Journal of the Linnean Society. 130 (4): 661–686. doi:10.1111/j.1096-3642.2000.tb02205.x. ISSN 0024-4082.
  5. ^ Moojen, Joao (December 10, 1948). Speciation in the Brazilian Spiny Rats: Genus Proechimys, Family Echimyidae. University of Kansas Publications. pp. 373–384. ISBN 978-1-258-64644-8. {{cite book}}: ISBN / Date incompatibility (help)
  6. ^ a b c d e Patton, James L.; Pardiñas, Ulyses F. J.; D’Elía, Guillermo (2015). Mammals of South America, Volume 2: Rodents. University of Chicago Press. doi:10.7208/chicago/9780226169606.001.0001. ISBN 978-0-226-16957-6.
  7. ^ a b c Oliveira, Marcelo de Assis Passos; Vilasboa, Anderson; Oliveira, Marcione Brito; Bonvicino, Cibele Rodrigues (2025-02-18), Population structure of endemic Atlantic Forest spiny rats Trinomys dimidiatus and Trinomys iheringi (Echimyidae), doi:10.21203/rs.3.rs-4837229/v2, retrieved 2025-04-01
  8. ^ TAVARES, WILLIAM CORRêA; PESSôA, LEILA MARIA; Seuánez, Hector N. (2016-09-01). "Stability and acceleration of phenotypic evolution in spiny rats (Trinomys, Echimyidae) across different environments". Zoological Journal of the Linnean Society. 178 (1): 149–162. doi:10.1111/zoj.12406. ISSN 0024-4082.
  9. ^ a b Fagundes, V.; Camacho, J.P.M.; Yonenaga-Yassuda, Y. (2004-08-18). "Are the dot-like chromosomes in Trinomys iheringi (Rodentia, Echimyidae) B chromosomes?". Cytogenetic and Genome Research. 106 (2–4): 159–164. doi:10.1159/000079282. ISSN 1424-8581. PMID 15292586.
  10. ^ Araújo, Naiara Pereira; Dias, Cayo Augusto Rocha; Stumpp, Rodolfo; Svartman, Marta (2018). "Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes". PeerJ. 6: e5316. doi:10.7717/peerj.5316. ISSN 2167-8359. PMC 6074804. PMID 30083457.
  11. ^ Yonenaga-Yassuda, Yatiyo; De Souza, Maria José; Kasahara, Sanae; L'Abbate, Miriam; Chu, Hsi Tien (1985-01-01). "Supernumerary System in Proechimys Iheringi Iheringi (Rodentia, Echimyidae), from the State of São Paulo, Brazil". Caryologia. 38 (2): 179–194. doi:10.1080/00087114.1985.10797742. ISSN 0008-7114.
  12. ^ Nacif, Camila Leitão; Bastos, Diogo Lisbôa; Mello, Beatriz; Lazar, Ana; Hingst-Zaher, Erika; Geise, Lena; Bonvicino, Cibele Rodrigues (2023-05-01). "Hidden diversity of the genus Trinomys (Rodentia: Echimyidae): phylogenetic and populational structure analyses uncover putative new lineages". Zoological Journal of the Linnean Society. 198 (1): 113–130. doi:10.1093/zoolinnean/zlac073. ISSN 0024-4082.
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