View source for Lundomys

{{Short description|Species of semiaquatic rat from southeastern South America}}
{{Use shortened footnotes|date=February 2024}}
{{Speciesbox
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=iucn>González et al., 2016</ref>
| fossil_range = Late [[Pleistocene]] to Recent ([[Lujanian]])
| image = Lundomys molitor type 2.png 
| image_alt = From top to bottom: side view of skull with mandible, missing the upper incisor and much of the posterior part; text "2. Hesperomys molitor"; and views of the same skull from above and below
| image_caption = [[Lectotype]] partial [[cranium]] of ''L. molitor''. The illustrated [[mandible]] represents a different species.
| genus = Lundomys
| parent_authority = Voss & [[Michael D. Carleton|Carleton]], 1993
| species = molitor
| authority = ([[Herluf Winge|Winge]], 1887)
| synonyms_ref = <ref name=VC5>Voss and Carleton, 1993, p.&nbsp;5</ref>
| synonyms =
* ''Hesperomys molitor'' <small>Winge, 1888</small>
* ''Oryzomys molitor'': <small>Trouessart, 1898</small>
* ''Holochilus magnus'' <small>[[Philip Hershkovitz|Hershkovitz]], 1955</small>
* ''Calomys molitor'': <small>Hershkovitz, 1962</small>
* ''Holochilus molitor'': <small>Massoia, 1980</small>
* ''Lundomys molitor'': <small>Voss and Carleton, 1993</small>
| range_map = Lundomys distribution.png
| range_map_alt = Map of South America marked by red and blue colors, with the red color extending over Uruguay and into Rio Grande do Sul, southern Brazil, and the blue color in southeastern Minas Gerais, eastern Brazil, and in two different areas in northern and southern Buenos Aires Province, eastern Argentina
| range_map_caption = Distribution of ''Lundomys molitor'' in South America. The current distribution is in red, and fossil records outside the current range are in blue.
}}

'''''Lundomys molitor''''', also known as '''Lund's amphibious rat'''<ref name="Carleton 2005">Musser and Carleton, 2005, p.&nbsp;1124</ref> or the '''greater marsh rat''',<ref>González et al., 2016; Duff and Lawson, 2004, p.&nbsp;56</ref> is a [[semiaquatic]] rat [[species]] from southeastern [[South America]].

Its distribution is now restricted to [[Uruguay]] and nearby [[Rio Grande do Sul]], [[Brazil]], but it previously ranged northward into [[Minas Gerais]], Brazil, and southward into eastern [[Argentina]]. The Argentine form may have been distinct from the living form from Brazil and Uruguay. ''L.&nbsp;molitor'' is a large [[rodent]], with the head and body length averaging {{convert|193|mm|in|abbr=on}}, characterized by a long tail, large hindfeet, and long and dense fur. It builds nests above the water, supported by reeds, and it is not currently threatened.

Its external [[morphology (biology)|morphology]] is similar to that of ''[[Holochilus brasiliensis]]'', and over the course of its complex [[taxonomy (biology)|taxonomic]] history it has been confused with that species, but other features support its placement in a distinct [[genus]], '''''Lundomys'''''. Within the family [[Cricetidae]] and subfamily [[Sigmodontinae]], it is a member of a group of specialized [[Oryzomyini|oryzomyine]] rodents that also includes ''[[Holochilus]]'', ''[[Noronhomys]]'', ''[[Carletonomys]]'', and ''[[Pseudoryzomys]]''.

== Taxonomy ==
''Lundomys molitor'' was first described in 1888 by Danish zoologist [[Herluf Winge]], who reviewed the materials [[Peter Wilhelm Lund]] had collected in the caves of [[Lagoa Santa, Minas Gerais]], Brazil. Winge used four specimens for his description, including two skull fragments and an isolated [[maxilla]] (upper jaw) from the cave chamber Lapa da Escrivania Nr.&nbsp;5 and a [[mandible]] (lower jaw) from Lapa da Serra das Abelhas, but the latter later turned out to be from a different species,<ref>Voss and Carleton, 1993, p.&nbsp;6</ref> probably ''[[Gyldenstolpia fronto]]''.<ref>Pardiñas et al., 2008, pp.&nbsp;556–557</ref> Lund named the animal ''Hesperomys molitor'' and placed it in the same genus (''[[Hesperomys]]'') as what is now ''[[Pseudoryzomys|Pseudoryzomys simplex]]'' and two species of ''[[Calomys]]''. Subsequently, it was rarely mentioned in the literature on South American rodents; those authors who did mention it placed it in either ''[[Oryzomys]]'' or ''Calomys''.<ref name=VC3>Voss and Carleton, 1993, p.&nbsp;3</ref>

In 1926, American zoologist [[Colin Campbell Sanborn]] collected some rodents in Uruguay, which he identified as ''Holochilus vulpinus'' (currently ''Holochilus brasiliensis'') in his 1929 report on the collection. When his successor at the [[Field Museum of Natural History]], [[Philip Hershkovitz]], reviewed ''Holochilus'' in 1955, he recognized that the series from Uruguay contained two species, one close to the forms of ''Holochilus'' found across much of South America, and another unique to Uruguay and southern Brazil; he named the latter as a new species, ''Holochilus magnus''. Hershkovitz identified ''Holochilus'' as one of the members of a "sigmodont" group of American rodents, also including ''[[cotton rat|Sigmodon]]'', ''[[Reithrodon]]'', and ''[[Neotomys]]'', on the basis of its flat-crowned [[molar (tooth)|molars]], which are [[lophodont]] (the crown consists of transverse ridges).<ref name=VC3 /> In 1981, ''H. magnus'' was also recognized in the [[Late Pleistocene]] of [[Buenos Aires Province]], Argentina,<ref name=VC10>Voss and Carleton, 1993, p.&nbsp;10</ref> and in 1982 it was recorded from Rio Grande do Sul in southern Brazil.<ref>Oliveira et al. in Freitas et al., 1983</ref>

In a 1980 article, Argentine zoologist Elio Massoia recognized the resemblance between Winge's ''Hesperomys molitor'' and Hershkovitz's ''Holochilus magnus'', and recommended that the former be reclassified as a species of ''Holochilus'', ''Holochilus molitor''.<ref>Voss and Carleton, 1993, pp.&nbsp;3, 6</ref> When American zoologists Voss and Carleton restudied Winge's material in a 1993 paper, they were unable to find any consistent differences between the two and accordingly considered them to pertain to the same species.<ref>Voss and Carleton, 1993, p.&nbsp;4</ref> In addition, they reviewed the differences between this species and other ''Holochilus'' and concluded that these were significant enough to place the former in a distinct genus, which they named ''Lundomys'' after Lund, who had collected the original material.<ref name="VC5" /> Since then, the species has been known as ''Lundomys molitor''.<ref name="Carleton 2005" />

In the same paper in which they described ''Lundomys'', Voss and Carleton also, for the first time, diagnosed the tribe [[Oryzomyini]] in a [[phylogenetics|phylogenetically]] valid way.<ref name=VC31>Voss and Carleton, 1993, p.&nbsp;31</ref> Previously, Oryzomyini had been a somewhat loosely defined group defined among others by a long [[palate]] and the presence of a crest known as the [[mesoloph]] on the upper molars and [[mesolophid]] on the lower molars; this crest is absent or reduced in ''Holochilus'' and ''Lundomys''.<ref>Voss and Carleton, 1993</ref> Voss and Carleton recognized five [[synapomorphy|synapomorphies]] for the group, all of which are shared by ''Lundomys'';<ref name=VC31 /> the placement in Oryzomyini of ''Lundomys'' and of three other genera—''Holochilus'', ''Pseudoryzomys'', and ''[[Zygodontomys]]''—which also lack complete mesoloph(id)s has been universally supported since.<ref>Musser and Carleton, 2005; Weksler, 2006</ref>

Voss and Carleton had found some support for a close relationship between ''Holochilus'', ''Lundomys'', and ''Pseudoryzomys'' within Oryzomyini.<ref>Voss and Carleton, 1993, p.&nbsp;1</ref> In subsequent years, the related species ''[[Holochilus primigenus]]'' and ''[[Noronhomys|Noronhomys vespuccii]]'' were discovered, providing additional evidence for this grouping.<ref>Steppan, 1996; Carleton and Olson, 1999</ref> The allocation of the former, which is similar to ''Lundomys'' in features of the dentition, to ''Holochilus'' is controversial, and placement as a second species of ''Lundomys'' has been suggested as an alternative.<ref>Pardiñas, 2008, p.&nbsp;1275</ref> A comprehensive phylogenetic analysis of oryzomyines by Marcelo Weksler, published in 2006, supported a close relationship among ''Lundomys'', ''Holochilus'', and ''Pseudoryzomys''; the other species of the group were not included. Data from the sequence of the [[RBP3|IRBP]] gene supported a closer relationship between ''Holochilus'' and ''Pseudoryzomys'', with ''Lundomys'' more distantly related, but [[morphology (biology)|morphological]] data placed ''Holochilus'' and ''Lundomys'' closer together, as did the combined analysis of both morphological and IRPB data.<ref>Weksler, 2006</ref> Subsequently, ''[[Carletonomys|Carletonomys cailoi]]'' was described as an additional relative of ''Holochilus'' and ''Lundomys''.<ref>Pardiñas, 2008</ref>

== Description ==
''Lundomys molitor'' is among the largest living oryzomyines, rivaled only by some large forms of ''[[Holochilus]]'' and ''[[Nectomys]]'', but it is substantially smaller than some of the recently extinct [[rodents of the Caribbean#Leeward Islands|Antillean species]], such as "''[[Ekbletomys hypenemus]]''" and ''[[Megalomys desmarestii]]''.<ref>Weksler, 2006, table&nbsp;8; Voss and Myers, 1991, table&nbsp;1; Ray, 1962, tables&nbsp;7, 11</ref> Unlike in ''[[Holochilus brasiliensis]]'', which occurs in the same area, the tail is longer than the head and body.<ref>Voss and Carleton, 1993, p.&nbsp;13</ref> It is sparsely haired and dark, and there is no difference in color between the upper and lower side. The coat, which is long, dense, and soft, is yellow–brown at the sides, but becomes darker on the upperparts and lighter on the underparts.<ref name=VC7>Voss and Carleton, 1993, p.&nbsp;7</ref> The large hindfeet are characterized by conspicuous [[interdigital webbing]], but they lack [[ungual tuft|tufts of hair]] on the digits and several of the [[paw#Common characteristics|pads]] are reduced.<ref>Voss and Carleton, 1993, p.&nbsp;6; Weksler, 2006, p.&nbsp;23</ref> As in some other semiaquatic oryzomyines, [[natatory fringe|fringes of hair]] are present along the [[plantar]] margins and between some of the digits.<ref>Voss and Carleton, 1993, p.&nbsp;7; Weksler, 2006, pp.&nbsp;24–25</ref> The forefeet also lack tufts on the digits and show very long claws, a character unique among oryzomyines.<ref>Weksler, 2006, pp.&nbsp;19, 23</ref> The female has four pairs of [[mammary gland|teats]], and the [[gallbladder|gall bladder]] is absent, both important characters of oryzomyines.<ref>Voss and Carleton, 1993; Weksler, 2006, table&nbsp;5</ref> The head and body length is {{convert|160|to|230|mm|in|abbr=on}}, averaging {{convert|193|mm|in|abbr=on}}, the tail length is 195 to 255&nbsp;mm (7.68 to 10.04&nbsp;mm), averaging {{convert|235|mm|in|abbr=on}}, and the length of the hindfoot is {{convert|58|to|68|mm|in|abbr=on}}, averaging {{convert|62|mm|in|abbr=on}}.<ref group="fn">Measurements for head and body length and tail length are from 10 specimens, and those for hindfoot length are from 12&nbsp;specimens, all from Uruguay.</ref><ref>Voss and Carleton, 1993, table&nbsp;2.</ref>

The front part of the skull is notably broad.<ref name=VC7 /> As in ''Holochilus'', the [[zygomatic plate]], the flattened front portion of the [[zygomatic arch|cheek bone]], is expansive and produced into a spinous process at the anterior margin. The [[jugal]] bone is small, but less reduced than in ''Holochilus''.<ref name=VC15>Voss and Carleton, 1993, p.&nbsp;15</ref> The [[interorbital region]] of the skull is narrow and flanked by high beads.<ref name=VC7 /> The [[incisive foramen|incisive foramina]], which perforate the palate between the [[incisor]]s and the upper molars, are long, extending between the molars.<ref name=VC15 /> The palate itself is also long, extending beyond the posterior margin of the maxillary bones,<ref>Voss and Carleton, 1993, p.&nbsp;16; Weksler, 2006, pp.&nbsp;34–35</ref> and it is perforated near the third molars by conspicuous [[posterolateral palatal pit]]s.<ref>Voss and Carleton, 1993, p.&nbsp;16</ref> As in all oryzomyines, the [[squamosal]] bone lacks a suspensory process that contacts the [[tegmen tympani]], the roof of the [[tympanic cavity]], but ''Lundomys'' is unusual in that the squamosal and the tegmen tympani usually overlap when viewed from the side.<ref>Weksler, 2006, p.&nbsp;40; Voss and Carleton, 1993, p.&nbsp;17</ref> In the mandible, the [[angular process|angular]] and [[coronoid process of the mandible|coronoid processes]] are less well-developed than in ''Holochilus''.<ref>Voss and Carleton, 1993, p.&nbsp;17</ref> The [[capsular process]] of the lower incisor, a slight raising of the mandibular bone at the back end of the incisor, near the coronoid process, is small. The two [[masseteric ridge]]s, to which some of the chewing muscles are attached, are entirely separate, joining only at their anterior edges, which are located below the first molar.<ref>Weksler, 2006, p.&nbsp;47</ref>

The molars are slightly more high-crowned ([[hypsodont]]) than in most oryzomyines, and many of the accessory crests are reduced, but they are sharply distinct from the highly [[synapomorphy|derived]], hypsodont molars of ''Holochilus''.<ref name=VC19>Voss and Carleton, 1993, p.&nbsp;19</ref> The main cusps are located opposite each other and have rounded edges. The enamel folds do not extend past the midlines of the molars.<ref name=VC19 /> The mesoloph, an accessory crest on the upper molars that is usually well-developed in oryzomyines, is present but short on the first and second upper molar; it is much more reduced in ''Holochilus'' and ''Pseudoryzomys''.<ref>Voss and Carleton, 1993, p.&nbsp;20; Weksler, 2006, fig.&nbsp;25</ref> The corresponding structure on the lower molars, the mesolophid, is present on the first and second molars in ''Lundomys'', but absent in both ''Holochilus'' and ''Pseudoryzomys''.<ref>Voss and Carleton, 1993, p.&nbsp;20; Weksler, 2006, p.&nbsp;49</ref> Another accessory crest, the [[anteroloph]], is present, though small, on the first upper molar in ''Lundomys'', but entirely absent in both other genera.<ref>Weksler, 2006, p.&nbsp;45</ref> As in ''Holochilus'' and ''Pseudoryzomys'', the anterior cusp on the first lower molar, the [[anteroconid]], contains a deep pit.<ref>Voss and Carleton, 1993, p.&nbsp;20</ref> Each of the three upper molars has three [[Dental anatomy#Anatomic landmarks|roots]]; unlike in both ''Holochilus'' and ''Pseudoryzomys'', the first upper molar lacks an accessory fourth root.<ref>Weksler, 2006, pp.&nbsp;42–43</ref> The first lower molar has four roots, including two small accessory roots located between larger anterior and posterior roots. The second molar has either two or three roots, with the anterior root split into two smaller roots in some specimens.<ref>Weksler, 2006, p.&nbsp;43</ref>

The [[karyotype]] contains 52&nbsp;[[chromosome]]s with a total of 58&nbsp;major arms (2n&nbsp;=&nbsp;52, [[Fundamental number|FN]]&nbsp;=&nbsp;58). The non-sex chromosomes (autosomes) are mostly [[acrocentric]], having a long and a short arm, or [[telocentric]], having only one arm, but there are also three large [[centromere#Metacentric|metacentric]] pairs, which have two major arms, and a small metacentric pair. The [[Y chromosome]] is metacentric and the [[X chromosome]] is variable, ranging from nearly metacentric to acrocentric in five specimens studied.<ref>Freitas et al., 1983; Voss and Carleton, 1993, p.&nbsp;10</ref>

== Distribution and ecology ==
''Lundomys molitor'' has been found as a living animal only in Uruguay and nearby [[Rio Grande do Sul]]; records of live specimens from eastern Argentina and Lagoa Santa, [[Minas Gerais]], have not been confirmed.<ref name=VC10 /> It is rarely encountered, and has been collected in only one location in Rio Grande do Sul, but this may be due to insufficient efforts to locate it, rather than genuine rarity.<ref>González et al., 2016; Bonvicino et al., 2008</ref> Its distribution is generally limited to areas with mean winter temperatures over {{convert|12|°C|°F|abbr=on}}, mean annual temperatures over {{convert|18|°C|°F|abbr=on}}, annual rainfall over {{convert|1,100|mm|in|abbr=on}}, and a long rainy season averaging over 200 days. It is usually found in swamps or near streams.<ref>Teta and Pardiñas, 2006, p.&nbsp;179</ref>

[[Pleistocene]] fossils have been found throughout its current range and beyond it. In Uruguay and Rio Grande do Sul, the [[Lujanian]] (Late Pleistocene to Early Holocene) [[Sopas Formation]] has yielded remains of ''L. molitor'', in addition to such other mammals as the extinct saber-toothed cat ''[[Smilodon populator]]'' and species of ''[[Glyptodon]]'', ''[[Macrauchenia]]'', and ''[[Toxodon]]''.<ref>Oliveira and Kerber, 2009; Ubilla et al., 2004</ref> The [[type locality (biology)|type locality]], Lagoa Santa, lies far northeast of the nearest record of live ''L. molitor''; there, it is known only from three skull fragments from a cave known as Laga da Escrivania Nr.&nbsp;5. This cave also contains numerous remains of members of the extinct South American [[megafauna]], such as [[ground sloth]]s, [[litopterna]]ns, [[gomphothere]]s, and [[Glyptodontidae|glyptodonts]], in addition to 16&nbsp;species of [[Cricetidae|cricetid]] rodents, but it is not certain that all remains from this cave are from the same age.<ref>Voss and Myers, 1991, table&nbsp;5, p.&nbsp;429</ref>

Remains of ''Lundomys'' have been found at six Pleistocene localities in [[Buenos Aires Province]], Argentina, which suggests a warm and humid paleoclimate there.<ref>Teta and Pardiñas, 2006</ref> The oldest deposits, at [[Bajo San José]], date to [[Marine Isotopic Stage 11]], about 420,000 to 360,000&nbsp;years ago, while younger specimens from other localities are as little as 30,000&nbsp;years old.<ref>Teta and Pardiñas, 2006, p.&nbsp;180</ref> The younger Argentine ''Lundomys'' specimens are subtly distinct from living ''Lundomys'' in some features of the first lower molar and may represent a distinct species. One lower first molar of this form has length 3.28&nbsp;mm.<ref>Pardiñas and Lezcano, 1995, pp.&nbsp;258–259</ref> Because the Bajo San José material does not contain lower first molars, it is impossible to determine whether this material also pertains to the later Argentine ''Lundomys'' form. The morphology of the upper and lower jaw precludes an identification as ''[[Holochilus primigenus]]'', a fossil species with molar traits almost identical to those of ''Lundomys''.<ref>Pardiñas and Deschamps, 1995, p.&nbsp;850</ref> The length of the upper toothrow of one specimen from this locality is {{convert|8.50|mm|in|abbr=on}} and the length of the upper first molar is {{convert|3.48|mm|in|abbr=on}},<ref>Pardiñas and Deschamps, 1995, table&nbsp;2</ref> slightly smaller than in living ''Lundomys'', which ranges from {{convert|3.56|to|3.64|mm|in|abbr=on}} in four specimens<ref>Pardiñas, 2008, table&nbsp;1</ref>

== Natural history ==
''Lundomys molitor'' is semiaquatic in habits, spending much of its time in the water, and is active during the night.<ref name=VC34>Voss and Carleton, 1993, p.&nbsp;34</ref> An excellent swimmer,<ref>Carleton and Olson, 1999, p.&nbsp;52</ref> it is even more specialized for swimming than is ''Holochilus''.<ref>Hershkovitz, 1955, p.&nbsp;658</ref> It builds a spherical [[nest]] among reeds in up to {{convert|1.5|m|ft|abbr=on}} deep water, usually about {{convert|20|cm|in|round=0.5|abbr=on}} above the water. The material for the nest, which is {{convert|25|to|30|cm|in|round=0.5|abbr=on}} in diameter and 9 to 11&nbsp;cm (about 4&nbsp;in) in height, comes from the surrounding reeds. Its wall consists of three layers, surrounding a central chamber, which is connected to the water by a ramp, also composed of reeds.<ref>Sierra de Soriano in Voss and Carleton, 1993, p.&nbsp;34</ref> Nests built by members of the related genus ''Holochilus'' are similar in many details.<ref name=VC34 /> Several dissected [[stomach]]s contained green plant material, suggesting that it is [[herbivore|herbivorous]], like ''Holochilus''.<ref>Barley in Voss and Carleton, 1993, p.&nbsp;34</ref> A female caught in April was pregnant with three embryos, which were about {{convert|12|mm|in|abbr=on}} long.<ref>Tuttle in Voss and Carleton, 1993, p.&nbsp;32</ref> The [[mite]]s ''[[Gigantolaelaps wolffsohni]]'' and ''[[Amblyomma dubitatum]]'' have been found on specimens of ''L.&nbsp;molitor'' in Uruguay.<ref>Lareschi et al., 2006; Nava et al., 2010, table&nbsp;1</ref> Other rodents found in association with it include ''[[Scapteromys tumidus]]'', ''[[Oligoryzomys nigripes]]'', ''[[Reithrodon auritus]]'', ''[[Akodon azarae]]'', ''[[Oxymycterus nasutus]]'', and ''Holochilus brasiliensis''.<ref>Voss and Carleton, 1993, pp.&nbsp;32–34</ref>

== Conservation status ==
The species' conservation status is currently assessed as "least concern" by the [[International Union for Conservation of Nature]], reflecting a relatively wide distribution and the absence of evidence for a decline in populations. Several of the areas where it occurs are protected, but the [[habitat destruction|destruction of its habitat]] may pose a threat to its continued existence.<ref name=iucn />

== Footnotes ==
{{Reflist|group="fn"}}

== References ==
{{Reflist|20em}}

== Literature cited ==
* Bonvicino, C.R., Oliveira, J.A. and D'Andrea, P.S. 2008. [https://web.archive.org/web/20110706161213/http://bvs1.panaftosa.org.br/local/File/textoc/Roedores_2008.pdf Guia dos Roedores do Brasil, com chaves para gêneros baseadas em characteres externos]. ''Série de Manuais Técnicos'' 11:1–120. Rio de Janeiro: Centro Pan-Americano de Febre Aftosa – OPAS/OMS (in Portuguese).
* Carleton, M.D. and Olson, S.L. 1999. [http://hdl.handle.net/2246/3097 Amerigo Vespucci and the rat of Fernando de Noronha: a new genus and species of Rodentia (Muridae, Sigmodontinae) from a volcanic island off Brazil's continental shelf]. ''American Museum Novitates'' 3256:1–59.
* Duff, A. and Lawson, A. 2004. ''Mammals of the World: A checklist''. New Haven: A & C Black, 312&nbsp;pp. {{ISBN|0-7136-6021-X}}.
* Freitas, T.R.O., Mattevi, M.S., Oliveira, L.F.B., Souza, M.J., Yonenaga-Yassuda, Y. and Salzano, F.M. 1983. [https://doi.org/10.1007%2FBF00563228 Chromosome relationships in three representatives of the genus ''Holochilus (Rodentia, Cricetidae)''<!--sic--> from Brazil] (subscription required). ''Genetica'' 61:13–20.
* {{cite iucn |author=Gonzalez, E.|author2=D'elia, G.|author3=Pardinas, U.|title=''Lundomys molitor'' |volume=2016 |errata=2017 |page=e.T10219A115096149 |year=2016 |doi=10.2305/IUCN.UK.2016-3.RLTS.T10219A22328078.en }}
* Hershkovitz, P.M. 1955. [https://www.biodiversitylibrary.org/bibliography/2902 South American marsh rats, genus ''Holochilus'', with a summary of sigmodont rodents]. ''Fieldiana Zoology'' 37:619–673.<!--pp. 657-658, under ''Holochilus magnus''-->
* Lareschi, M., Gettinger, D., Venzal, J.M., Arzua, M., Nieri-Bastos, F.A., Barros-Battesti, D.M. and Gonzalez, E.M. 2006. [http://www.scielo.br/scielo.php?pid=S1519-566X2006000500005&script=sci_arttext Primer registro de ácaros (Gamasida: Laelapidae) parásitos de roedores silvestres en Uruguay, con nuevos registros de hospedadores.] ''Neotropical Entomology'' 35(5):596–601 (in Spanish).
* {{MSW3 Muroidea |id=13000692 |page=1124}}
* Nava, S., Venzal, J.M., Labruna, M.B., Mastropaolo, M., González, E.M., Mangold, A.J. and Guglielmone, A.A. 2010. [https://dx.doi.org/10.1007/s10493-009-9331-6 Hosts, distribution and genetic divergence (16S rDNA) of ''Amblyomma dubitatum'' (Acari: Ixodidae)] (subscription required). ''Experimental and Applied Acarology'' 51(4):335–351.
* Oliveira, É.V. and Kerber, L. 2009. [https://web.archive.org/web/20110706162402/http://www.gaea.unisinos.br/pdf/61.pdf Paleontologia e aspectos geológicos das sucessões do final do Neógeno no sudoeste do Rio Grande do Sul, Brasil]. ''Gaea'' 5(1):21–34 (in Spanish).
* Pardiñas, U.F.J. 2008. [http://www.bioone.org/doi/abs/10.1644/07-MAMM-A-099.1 A new genus of oryzomyine rodent (Cricetidae: Sigmodontinae) from the Pleistocene of Argentina] (subscription required). ''Journal of Mammalogy'' 89(5):1270–1278.
* Pardiñas, U.F.J. and Deschamps, C. 1996. [http://estudiosgeol.revistas.csic.es/index.php/estudiosgeol/article/download/277/280 Sigmodontinos (Mammalia, Rodentia) Pleistocenicos del sudoeste de la provincia de Buenos Aires (Argentina): Aspectos sistematicos, paleozoogeograficos y paleoambientales]. ''Estudios Geológicos'' 52:367–379 (in Spanish).
* Pardiñas, U.F.J. and Lezcano, M.J. 1995. [https://books.google.com/books?id=uGIV-JUKgd0C&oi=fnd&pg=PA249 Cricetidos (Mammalia: Rodentia) del Pleistoceno tardio del nordeste de la provincia de Buenos Aires (Argentina). Aspectos sistematicos y paleoambientales]. ''Ameghiniana'' 32(3):249–265 (in Spanish).
* Pardiñas, U.F.J., D'Elía, G. and Teta, P. 2008. Una introducción a los mayores sigmodontinos vivientes: Revisión de ''Kunsia'' Hershkovitz, 1966 y descripción de un nuevo género (Rodentia: Cricetidae). ''Arquivos do Museu Nacional'' 66(3–4):509–594.
* Ray, C.E. 1962. The Oryzomyine Rodents of the Antillean Subregion. Doctor of Philosophy thesis, Harvard University, 211 pp.
* Steppan, S.J. 1996. [https://www.jstor.org/pss/4523740 A new species of ''Holochilus'' (Rodentia: Sigmodontinae) from the Middle Pleistocene of Bolivia and its phylogenetic significance] (subscription required). ''Journal of Vertebrate Paleontology'' 16(3):522–530.
* Teta, P. and Pardiñas, U.F.J. 2006. "Pleistocene record of marsh rats of the genus ''Lundomys'' in southern South America: Paleoclimatic significance". ''Current Research in the Pleistocene'' 23:179–181.
* Ubilla, M., Perea, D., Aguilar, C.G. and Lorenzo, N. 2004. [http://linkinghub.elsevier.com/retrieve/pii/S104061820300048X Late Pleistocene vertebrates from northern Uruguay: tools for biostratigraphic, climatic and environmental reconstruction] (subscription required). ''Quaternary International'' 114:129–142.
* Voss, R.S. and Carleton, M.D. 1993. [http://hdl.handle.net/2246/4982 A new genus for ''Hesperomys molitor'' Winge and ''Holochilus magnus'' Hershkovitz (Mammalia, Muridae) with an analysis of its phylogenetic relationships]. ''American Museum Novitates'' 3085:1–39.
* Voss, R.S. and Myers, P. 1991. [http://hdl.handle.net/2246/900 ''Pseudoryzomys simplex'' (Rodentia: Muridae) and the significance of Lund's collections from the caves of Lagoa Santa, Brazil]. ''Bulletin of the American Museum of Natural History'' 206:414–432.
* Weksler, M. 2006. [http://hdl.handle.net/2246/5777 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.

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[[Category:Extant Pleistocene first appearances]]
[[Category:Rodents of Brazil]]
[[Category:Mammals of Uruguay]]
[[Category:Monotypic rodent genera]]
[[Category:Oryzomyini]]
[[Category:Mammals described in 1888]]
[[Category:Taxa named by Michael D. Carleton]]