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3.3.1 Metachirus aritanai new species 3.3.1.1 Synonymy (Didelphys [Metachirus]) nudicaudata: Trouessart 1989:1236; part, not M. nudicaudatus (Geoffroy St. Hilaire 1803). [Philander] nudicaudatus: Pine 1973:391; part, not M. nudicaudatus (Geoffroy St. Hilaire 1803). M. nudicaudatus: Patton et al. 2000:61–64; not M. nudicaudatus (Geoffroy St. Hilaire 1803); first evidence that Metachirus from Pará represented a new taxon. M [etachirus]. n [udicaudatus]. nudicaudatus: Gardner and Dagosto 2007:37; part, not M. nudicaudatus (Geoffroy St. Hilaire 1803). Holotype: An adult male consisting of skin and skull (INPA 2831, original number CS 83), in addition to tissue sample preserved in ethanol, collected on 8 July 1999 by Maria Nazareth F. da Silva in the Tapirapé-Aquiri National Forest, Marabá, Pará, Brazil (05° 46′ 53.10″ S; 50° 31′ 48.60″ W; Figure 1). MC, male from the Carajás region; FC, females from the Carajás region; MN, male of M. nudicaudatus; FN, females of M. nudicaudatus; MM, males of M.myosuros; FM,females of M.myosuros; MCC,maximal cranial circumference;NAS,nasal bone length;RWJ,rostrum width between the jugal bones;RWF, rostrum width between the frontal bonés;NW, greater nasal width; CI, interorbital constriction; PC,postorbital constriction; WZ,width between zygomatic arches; GCW, greatest cranial width; MAX, length of the maxillary row of teeth; LUM, length of the upper molar series; CAN, width between the lateral margins of the upper canines; WPP, width of the palatal projection; WM, width between the external faces of the third molars; LLM, length of the lower molar series; JL, jaw length. Paratypes ( N = 19): Eight adult females (N = 8) consisting of skins, skulls and tissues preserved in ethanol; two adult males (N = 2) consisting of skins, skulls and tissues preserved in ethanol; and five sub-adult and young individuals (N = 9) consisting of specimens preserved in fluid, skull and tissues. Adult females: two specimens (PSA 06; PSA 200) were collected by Cleuton L. Miranda in the Tapirapé-Aquiri National Forest, municipality of Marabá, Pará, Brazil and will be cataloged in the mammal collection of MPEG. Three specimens were collected by Natalia C. Ardente, two (MN 78307; MN 79953) in the Carajás National Forest, municipality of Marabá, Pará, Brazil, and one (MN 75549) in the Tapirapé-Aquiri National Forest, municipality of Marabá, Pará, Brazil. The three remaining specimens (LBCE 14843, 14845, 14859) were collected by Fabiana Caramaschi, Cibele R. Bonvicino and Paulo Sérgio D’ Andrea in the Vila Santa Cruz, Araguatins municipality, State of Tocantins, Brazil, and will be cataloged in the mammal collection of MN. Adult male specimens: two specimens (MN 73864; MN 78309) were collected by Natalia C. Ardente in the Carajás National Forest, State of Pará, Brazil. Sub-adult and young specimens: nine specimens were collected by Marco Antonio R. Junior and Stepheson Abrantes; five specimens (MAR 890, 1165, 1292, 1407, 1409) were collected in the Caxiuanã National Forest, municipality of Portel, Pará, Brazil, and will be cataloged in the mammal collection of MPEG; Four specimens (CN 78, 83, 91, 240) were collected in Bom Futuro on the left margin of the middle Xingu River, Pará, Brazil, and will be cataloged in MPEG. Type locality: Tapirapé-Aquiri National Forest, municipality of Marabá, state of Pará, Brazil (05° 46′ 53.10″ S; 50° 31′ 48.60″ W; Figure 1). Etymology: The name M. aritanai is given in honor of the great leader Aritana Yawalapiti (1949–2020), of the Yawalapiti ethnicity, from the upper Xingu River region and in honour of all indigenous peoples of Brazil. The leader Aritana died in August 2020, a victim of covid-19, representing a great loss for the Xingu people, all indigenous peoples, and all Brazilians. Distribution: M. aritanai new species is restricted to the Xingu-Tocantins interfluve, the endemism center Xingu sensu Silva et al. (2005). As far as we know M. aritanai new species is endemic to this biogeographic region (Figure 1). The species is bounded to the north by the Amazon River, to the west by the Xingu River and to the east by the Tocantins River. The southern boundary cannot yet be clearly defined. According to the consensus topology and times of divergence presented in this study, a sister species of M. aritanai new species, M. nudicaudatus, occurs north of the Amazon River (Figures 2 and 3). Diagnosis: M. aritanai new species is characterized by the combination of the following characters: general colouration light brown with speckles of gold on the back; small amount of rust hair behind the ears; supra-ocular spots of cream colour; cheeks with the same colouration as supra-ocular spots; brown and gold-speckled face; absence of median stripe on the rostrum; the presence of a narrow, blackened dorsal line at the top of the head, usually extending to the nape of the neck; clear ventral surface, usually pure cream, wide interorbital region (average = 12.12 mm) and with incipient ridges; rounded and inflated cranial cavity, with large maxillopalatine (average = 24.68 mm) and fenestrae; small entoconids; absent or incipient temporal crest. Figures 5–7 show the mentioned characters, except for the morphology of the entoconid, which is similar to that of M. nudicaudatus and may be seen in Figure 15, page 46 in Voss et al. (2019). 3.4 Description 3.4.1 External morphology Combined length of adult head and body ca. 230 mm on average (ranging 243–275 mm); adult weight ca. 380 g. Midrostral fur cream coloured with apical portion dark brown (most of the cream-coloured hairs have black tips, but there are also completely blackened or cream hairs in lesser quantities, somewhat like the dorsal coat). Dark median rostral stripe absent or inconspicuous. Dark circumocular mask present (blackened), extending posteriorly to the base of the ear, continuous with the coronal fur. Narrow dark brown dorsal line starting at the coronal spot and extending to the end of the nape. Throat gland present in adult males. Small pure cream supraocular spots present, usually in the shape of an inverted triangle, varying in size. Pure cream-coloured cheeks, of the same colour as the supraocular spots. Completely brown ears. Presence of small amounts of rust hair behind the base of the ears. General colouration light brown speckled with gold. Dorsal colour pale brown, with grey-based hairs, cream stripe over most of its length and short blackish apex, giving the back a golden speckled appearance. Dorsal hairs usually do not exceed 10 mm in length. Dorsal guard hairs short, dark, and inconspicuous. Lateral portions of the body brown and lighter than the back. Ventral pelage usually pure cream, similar in colour to the supra-ocular spots and cheeks. Mammae 4–1–4 = 9, all abdominal inguinal. Pouch absent. Tail is light brown to dark brown, dorsal discolouring gradually towards the distal portion; ventral surface of the tail not pigmented. Scales without a consistent arrangement (both spiral and annular patterns coexisting). Tail longer than the length of the head and body, covered with 5–10 mm long hairs on all sides at the base. Hands and feet covered with cream-coloured hair, like the ventral coat; Manus mesaxonic (d III> d IV); Carpal tubercles absent in mature adult males. 3.4.2 Cranium-dental morphology Cranium wide and robust. Relatively elongated face. Nasal branch of the premaxilla developed. Rostral process of the premaxilla absent. Long nasal bone, widely enlarged in the region of the maxillary/frontal suture. Mandible developed, with elongated and deep infraorbital foramen at the height of the Pm2. Interorbital region-wide (average = 12.12 mm) with incipient ridges. Lacrimal bone extends in the rostrum to the anterior margin of the orbital cavity, surpassing the two exposed lacrimal foramina. Zygomatic arch well developed, composed by the jugal and squamosal. Postorbital process of the jugal absent. Postorbital process of the frontal absent. Palatine articulates ventrally with mandible and dorsally with frontal. Frontal quite developed extending from the posterior region of the nasal branch of the mandible to the posterior region of the cranium, where it articulates with the parietal. Supraorbital crest imperceptible. Absent or incipient temporal crest. When incipient, the crest most often extends from the frontal to the parietal, where it can be joined to the midline of the cranium and extend to the lambdoidal crest. Lamboidal crest not developed. Sagittal crests absent in the anterior part of the occiput. Parietal articulates anteriorly with the frontal, but they are separated by median sutures on the right and on the left. Parietal articulates posteriorly with the supra-occipital and mastoid. Squamosal in contact with the frontal on the side of the cranium. Parietal and alisphenoid not in contact. Petrosal not exposed laterally. Squamosal parietal fenestra absent. Parietal and mastoid normally in contact. Interparietal not in contact with squamosal. Palate long, wide and composed mostly by the mandible, which articulates with the palatal branch of the pre-mandible at the height of the well-developed incisor foramen. Mandible articulates anteriorly with the palate. Maxillopalatine large (average = 24.68 mm) and fenestrated. Mandible and alisphenoid not connected at the bottom of the orbital region, separated by the palatine. Foramen of transverse canal absent. Tympanic process of alisphenoid laterally compressed and non-globular, slightly pointed or rounded. Anterior member of ectotympanic suspended directly from the basicranium. Paraoccipital process broad, erect, and ventrally projected. Dorsal margin of the foramen magnum in contact with exoccipital. Well-developed mandible. Dental formula i5/4, c1/1, pm3/3, m4/4. First upper premolar smaller than the second, well developed and non-vestigial. Second and third upper premolars equivalent in height. Post-metacrist bigger than post-protocrist in molars. The lower third premolar, when deciduous, has three cusps. Entoconids small. 3.4.3 Morphological variation We did not observe differences in the external morphology of males and females within any of the considered age groups (young, sub-adult or adult). However, there were significant age-related morphological differences. Young and sub-adult individuals had a general greyish and darker colour than adult individuals. Yet, sub-adults also exhibit some diagnostic characters of M. aritanai new species, such as cream supra-ocular spots and cheeks of the same colour, absence of median stripe on the rostrum and cream-pure ventral surface (Table 5). 3.4.4 Comparisons M. aritanai new species differs from the nominal form, M. nudicaudatus (sensu Voss et al. 2019 and present study) and from M. myosuros from the Atlantic Forest (sensu present study) by their dorsal colouring (light brown speckled with gold in M. aritanai vs. brown speckled with black and light orange in M. nudicaudatus, vs. brown-orange to light brown in M. myosuros); ventral surface colouring (purecream in M. aritanai vs. yellow-cream in M. nudicaudatus, vs. yellowish hues in M. myosuros); colouring of the sides of the body (similar to the dorsum but slightly lighter in M. aritanai vs. orange-brown, visibly lighter than the dorsum with conspicuous blackish and orange hairs in M. nudicaudatus vs. yellow with a variety of light greyish and even golden hues of grey and golden in M. myosuros); colouring of the supra-ocular spots (cream in M. aritanai vs. cream and slightly orange, especially at the edges in M. nudicaudatus, vs. yellow to cream in M. myosuros); lighter hair behind the ears (yellowish and in small amounts in M. aritanai vs. rust and in large quantities in M. nudicaudatus, vs. yellowish hues in M. myosuros); hair colour on the tarsus (cream in M. aritanai vs. brownish-orange in M. nudicaudatus, vs. varying hues from blackish to brownish-grey with golden fur in M. myosuros); width and robustness of the skull (wider and more robust in M. aritanai vs. narrower and more delicate in both M. nudicaudatus and M. myosuros); nasal width in relation to the maxillary (much narrower than the pre-maxillary in the initial portion and similar width in the end portion with a rounder end near frontal bone in M. aritanai vs. much narrower than the pre-maxillary in the initial portion and similar width in the end portion with a tapered end near frontal in both M. nudicaudatus and M. myosuros); contour of the pre-maxillary (wider, short and pointed in M. aritanai vs. narrower, long and rounded in M. nudicaudatus, vs. narrower, long and pointed in M. myosuros); frontal edges (irregular in the posterior portion with the presence of a protuberance in the median region in M. aritanai vs. more regular and rounded limit, without the presence of a median protuberance in M. nudicaudatus, vs. usually developed and pointed in M. myosuros); average differences in mitochondrial sequences of the Cytb gene (between M. aritanai and M. nudicaudatus = 8.2%; between M. aritanai and M. myosuros = 14.4%; Table 5; Figures 5–7)., Published as part of Miranda, Cleuton Lima, Nunes, Mario da Silva, Fabrício Machado, Arielli, Farias, Izeni Pires, Menezes, Fernando Heberson, Ardente, Natalia Carneiro, Dos Santos-Filho, Manoel, Bredin, Yennie Katarina & da Silva, Maria Nazareth F., 2023, A new species of jupati, genus Metachirus Burmeister 1854 (Didelphimorphia, Didelphidae) for the Brazilian Amazon, pp. 172-189 in Mammalia (Warsaw, Poland) (Warsaw, Poland) 87 (2) on pages 178-184, DOI: 10.1515/mammalia-2021-0176, http://zenodo.org/record/7837851, {"references":["Trouessart, E. - L. (1989). Catalogus mammalium tam viventium quam fossilium. Fasciculus V. Sirenia, Cetacea, Edentata, Marsupialia, Allotheria, Monotremata., 2. R. Friedlander & Sohn, Berolini, pp. 999 - 1264.","Pine, R. H. (1973). Anatomical and nomenclatural notes on opossums. Proc. Biol. Soc. Washington 86: 391 - 402.","Patton, J. L., da Silva, M. N. F., and Malcolm, J. R. (2000). Mammals of the Rio Jurua and the evolutionary and ecological diversification of Amazonia. Bull. Am. Mus. Nat. Hist. 244: 1 - 306.","Gardner, A. L. and Dagosto, M. (2007). Tribe Metachirini. In: Gardner, A. L. (Ed.). Mammals of South America. Volume 1: marsupials, xenarthrans, shrews, and bats. University of Chicago Press, Chicago, pp. 35 - 39.","Silva, J. M. C., Rylands, A. B., and da Fonseca, G. A. B. (2005). The fate of the Amazonian areas of rndemism. Conserv. Biol. 19: 689 - 694.","Voss, R. S., Fleck, D. W., and Jansa, S. A. (2019). Mammalian diversity and Matses ethnomammalogy in Amazonian Peru. Part 3. Marsupials (Didelphimorphia). Bull. Am. Mus. Nat. Hist. 432: 1 - 87."]}

Os trabalhos sobre dimorfismo sexual em Cebus disponíveis na literatura apontam Cebus apella como a espécie mais dimórfica do gênero. Contudo, vale ressaltar que diversas espécies de macacos-prego eram consideradas anteriormente subespécies de C. apella, sendo analisadas em conjunto nestes estudos. O arranjo taxonômico que segui neste estudo considera tais táxons como espécies válidas, com considerável grau de diferenciação morfológica. A maior parte destes estudos utilizou somente exemplares adultos, assumindo que os indivíduos cessariam seu crescimento assim que a sua dentição estivesse completa. A falta de estudos sobre idades anteriores à idade adulta pode resultar em um entendimento incompleto sobre a natureza do dimorfismo sexual, pois níveis similares deste dimorfismo podem ser gerados por diferentes processos ontogenéticos, refletindo causas evolutivas distintas. Com base nestas informações, os objetivos do presente estudo foram verificar as diferenças sexuais cranianas e no grau de desenvolvimento dos tufos do capuz da cabeça ao longo da ontogenia de seis espécies de macacos-prego, todas pertencentes ao subgênero Sapajus (Cebus apella, C. macrocephalus, C. libidinosus, C. cay, C. nigritus e C. robustus) e confrontar os resultados obtidos entre as espécies para constatar se existem diferenças interespecíficas. Para tanto, examinei 774 espécimes depositados em coleções científicas brasileiras. Mensurei 20 variáveis craniométricas, examinei 12 caracteres cranianos discretos e estabeleci quatro estados de caráter para o grau de desenvolvimento dos tufos do capuz. Avaliei o dimorfismo sexual através do teste t de Student com ajustamento de Bonferroni e empreguei Análise de Componentes Principais (ACP), seguida de Análise de Função Discriminante (AFD) para testar a significância dos agrupamentos etários (infantes, jovens, subadultos e adultos, sendo este último grupo dividido em AD1 e AD2 para C. apella). Os resultados mostraram que diferenças sexuais cranianas podem ser evidenciadas no subgênero Sapajus somente a partir da idade subadulta (aproximadamente 3,5 anos de idade), sendo o comprimento dos caninos a mais conspícua. Contudo, estas diferenças ainda não são estatisticamente significativas. Somente a partir da idade adulta (cerca de 5 anos de idade) a maior parte das variáveis cranianas passou a apresentar dimorfismo sexual significativo, com as espécies comportando-se de modo distinto em relação ao tipo e número de variáveis dimórficas. As espécies que apresentaram maior número de variáveis significativas foram C. apella e C. robustus (N=15), seguidas de C. nigritus (N=13), C. libidinosus (N=10), C. cay (N=7) e C. macrocephalus (N=3). Estudos anteriores apontam que o dimorfismo sexual craniano em Cebus (Sapajus) surge em indivíduos jovens (cerca de 27 meses de idade). Os resultados obtidos neste estudo não corroboram esta idéia, pois demonstram que o dimorfismo sexual significativo surge apenas em indivíduos adultos. Tais resultados ainda sugerem que o processo heterocrônico da taxa de hipermorfose representa o principal fator para o padrão ontogenético de dimorfismo sexual craniano exibido. A despeito do dimorfismo sexual craniano, as espécies de macacos-prego diferem entre si em relação ao grau de desenvolvimento dos tufos do capuz. Constatei que o desenvolvimento dos tufos do capuz em Cebus (Sapajus) está diretamente relacionado à idade, não existindo dimorfismo sexual quanto ao grau de desenvolvimento desta estrutura em C. cay, C. robustus e C. nigritus. Em contrapartida, parece existir dimorfismo sexual negativo em relação ao desenvolvimento dos tufos em C. libidinosus, fato que carece de maiores investigações. Por fim, os resultados deste estudo sugerem que as espécies de macacos-prego podem ter experimentado diferentes graus e/ou tipos de pressões seletivas quanto ao dimorfismo sexual ao longo de sua história evolutiva. The studies on sexual dimorphism available in the scientific literature have shown that Cebus apella is the most dimorphic species within the genus Cebus. However, it is worthy to say that several species of Cebus currently recognized were previously considered subspecies of C. apella, and were grouped as one single species in the studies mentioned above. This is not the case for the present report, in which I recognize six species previously assigned to C. apella. Additionally, most studies on sexual dimorphism in Cebus were based only on adult specimens, assuming that individuals exhibit no more growth after reaching complete permanent dentition. The lack of studies that take into account young or subadult specimens may result in a deficient knowledge about the origins of sexual dimorphism, because different ontogenetic processes may be related to the development of sexual dimorphism, all of them leading to similar results in adult specimens. Considering the issues mentioned above, the aims of the present study are to assess the sexual dimorphism in the skull and in the development degree of head tufts through different ontogenetic stages in six capuchin monkey species, all of them assigned to the subgenus Sapajus (Cebus apella, C. macrocephalus, C. libidinosus, C. cay, C. nigritus e C. robustus), and to evaluate the existence of taxonomic variation in the development and the amount of sexual dimorphism found. I examined 774 specimens housed in Brazilian institutions. I measured 20 cranial variables, examined 12 qualitative cranial characters, and established four character states for the development degree of the head tufts. I used the Student t Test with Bonferroni adjustment to evaluate the sexual dimorphism, and the Principal Component Analysis (PCA) followed by the Discriminant Analysis (DA) to test the statistical significance among the age classes herein recognized (infants, juveniles, subadults, and adults; the latter group was divided in AD1 and AD2 in C. apella). The results show that sexual differences in the skull of species of Sapajus can be found in subadult specimens (ca. 3.5 years old), of which the most conspicuous is the length of the upper canine. In this life stage, the sexual differences are not statistically significant. In adult specimens (ca. 5 years old), most cranial variables showed significant sexual dimorphism. The number and composition of the dimorphic variables varied among the different species included in this study. The species with more dimorphic variables were C. apella and C. robustus (N=15), followed by C. nigritus (N=13), C. libidinosus (N=10), C. cay (N=7), and C. macrocephalus (N=3). Different from previous studies available in the scientific literature, which states that sexual dimorphism in the skull of Cebus (Sapajus) arises in young specimens (ca. 27 months old), my results showed that a significant sexual dimorphism in this subgenus appears only in adult specimens. My results suggest that the heterocronic process of the hipermorphose rate is the main cause of the sexual dimorphism pattern exhibited by Sapajus. The species of capuchin monkeys included in this study exhibited different degree of development in the head tufts. In general, the development degree of this character in Cebus (Sapajus) is related to the age class to which the specimen belongs. Moreover, there is no sexual dimorphism in this character in C. cay, C. robustus, and C. nigritus. By contrast, female specimens of C. libidinosus appear to exhibit more developed head tuft than male specimens. Finally, my results suggest that the species of capuchin monkeys analyzed herein may have experienced different kinds or intensities of selective pressure relative to sexual dimorphism during their evolutionary history.

Submitted by Maria Aparecida (cidazen@gmail.com) on 2022-12-12T13:16:09Z No. of bitstreams: 1 ODGLEY QUIXABA VIEIRAvec.pdf: 59673288 bytes, checksum: 944b104a3e9e0a8292566d3ec259ca51 (MD5) Made available in DSpace on 2022-12-12T13:16:09Z (GMT). No. of bitstreams: 1 ODGLEY QUIXABA VIEIRAvec.pdf: 59673288 bytes, checksum: 944b104a3e9e0a8292566d3ec259ca51 (MD5) Previous issue date: 2021-02-26 Brazil is the most biodiverse country on Earth, with the Amazon and Cerrado biomes in particular having high levels of species richness. In the state of Maranão, located in the midnorth region of the country, lies an ecotonal zone between the Amazon, Caatinga, and Cerrado biomes. This results in the region having areas with high biodiversity and conservation priority. Despite this, the mammalian fauna of the region is still poorly known. We sampled the nonvolant mammals at several sites in Maranhão state. Small mammals were sampled using live traps, whereas medium and large-sized mammals were surveyed through transect sampling, interviews, and camera traps. We also searched literature extensively through trustable digital platforms. We recorded 89 nonvolant species for Maranhão state, of which 23 are threatened with extinction. The ecotonal nature of the region was supported by the number of species associated to each biome (65 species for the Cerrado and 65 in the Amazon), as well as by a principal component analysis, showing extensive overlap among species of each biome. Historical events such as expansion-retraction of rainforests in open landscapes as well as contemporary habitat loss, resulted in some of the species being detected outside their known distribution limits. Species distribution models showed that an area of 69,000 km2 within the state is of high conservation priority for threatened mammalian species. These areas are located in the buffer zones of existing protected areas such as the Gurupi region, Chapada das Mesas National Park, Mirador State Park, the middle Parnaíba river, and the Nascentes do Rio Parnaíba National Park. Ensuring the protection of the areas identified in this study, will improve the long-term conservation prospects of threatened species by allowing viable populations and habitat connectivity between existing protected areas. O Brasil é o país detentor da maior diversidade biológica do planeta. Dentre seus inúmeros biomas, destacam-se a Amazônia e o Cerrado. A denominação de estado ecótono, por estar localizado na região meio-norte do Brasil, entre a Amazônia a Caatinga e o Cerrado, confere ao Maranhão áreas ricas e abundantes em espécies e consequentemente remete a cuidados especiais na sua conservação. Apesar de seu enorme potencial em biodiversidade, o Maranhão ainda possui sua riqueza biológica pouco conhecida, notadamente quanto à sua mastofauna. A metodologia empregada para inventariar a comunidade de pequenos mamíferos não-voadores foi a metodologia padrão de captura-recaptura, utilizando armadilhas do tipo live-traps. Para os mamíferos de médio e grande porte utilizou-se a visualização direta e indireta através da transecção de trilhas pré-estabelecidas assim como entrevistas e uso de armadilhas fotográficas. Para maximizar a busca pelos componentes de mamíferos constituintes já registrados no estado foram também realizadas buscas de literatura através de plataformas digitais confiáveis. Foram registradas 89 espécies de mamíferos não-voadores no Maranhão, onde 23 são consideradas ameaçadas de extinção. A transicionalidade do estado foi comprovada pela semelhança entre o número de espécies associadas aos biomas majoritários presentes no estado, onde 65 destas estão associadas ao Cerrado e 65 à Amazônia, e pela análise de componentes principais, que evidenciou sobreposição entre os agrupamentos de espécies associados a estes biomas. Eventos históricos de expansão-retração das florestas úmidas sobre os espaços ocupados por formações abertas de climas sazonais secos além do efeito da fragmentação nos deslocamentos de muitas espécies permitiu o registro de algumas destas em zonas limítrofes ou até mesmo fora do bioma de origem. As áreas prioritárias para a conservação dos mamíferos não voadores ameaçados no estado do Maranhão, obtidas a partir da média dos modelos de distribuição potencial para cada espécie ameaçada presente no estado, somaram 69 mil km2 . As áreas definidas como prioritárias para conservação por esse estudo estão concentradas no entorno das áreas protegidas da região do Gurupi, do Parque Nacional da Chapada das Mesas, conectando o Parque Estadual do Mirador com as reservas indígenas adjacentes, médio curso do Rio Parnaíba e extremo sul do estado, margeando o Parque Nacional das Nascentes do Rio Parnaíba. Conservar as áreas prioritárias definidas nesse estudo, aumentarão as chances de manutenção de populações viáveis das espécies assim como possibilitarão o deslocamento natural entre áreas que julgarem mais adequadas.

A subfamília Sigmodontinae Wagner, 1843, atualmente alocada na família Cricetidae Fischer, 1817, é o segundo grupo mais diverso dentro dos mamíferos. Esta subfamília é superada em riqueza de espécies apenas pela irradiação de muróideos asiáticos da família Muridae (Musser & Carleton, 2005). Os sigmodontíneos estão amplamente distribuídos nas Américas do Sul e Central e de forma periférica na América do Norte, alcançando o sudeste dos Estados Unidos. Esta subfamília reúne 86 gêneros e 384 espécies apenas na América do Sul, e em toda a sua área de distribuição devem ocorrer aproximadamente 95 gêneros e mais de 400 espécies (D’Elía & Pardiñas, no prelo). Essa alta diversidade está dividida em nove grupos supra-genéricos, alocados na categoria de tribo: Abrotrichini, Akodontini, Ichthyomyini, Oryzomyini, Phyllotini, Reithrodontini, Sigmodontini, Thomasomyini, Wiedomyini, além de alguns gêneros não alocados em nenhuma das tribos. Os agrupamentos mais diversos são as tribos Oryzomyini e Akodontini, que reúnem aproximadamente metade das espécies da subfamília. Fil: Reis Percequillo, Alexandre. No especifíca; Fil: de Abreu Júnior, Edson. Universidade de Sao Paulo; Brasil Fil: Bovendorp, Ricardo Siqueira. Universidade Estadual de Santa Cruz; Brasil Fil: Brennand, Pamella Gusmão de Góes. Escola Superior de Agricultura "Luiz de Queiroz"; Brasil Fil: Chiquito, Elisandra de Almeida. Instituto Nacional da Mata Atlântica; Brasil Fil: Correa, Lidiani Silva. No especifíca; Fil: Perez Godoy, Leandro. No especifíca; Fil: Simoes Libardi, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina Fil: Prado, Joyce Rodrigues Do. Universidade de Sao Paulo; Brasil Fil: Roth, Paulo Ricardo de Oliveira. Universidade de Sao Paulo; Brasil Fil: Lucena Salles, Vanessa. No especifíca