NOTA

New records of the elusive marsupial Gracilinanus emiliae (Didelphimorphia, Didelphidae) from the brazilian amazon basin and a range extension for the species

 

Marcus V. Brandão O.¹, Patrício A. da Rocha², Silionamã P. Dantas^{3, 4}, and Wanieulli Pascoal^{3, 5}

¹ Universidade Federal de São Carlos, Campus Sorocaba, Departamento de Biologia, Laboratório de Diversidade Animal, Rod. João Leme dos Santos (SP-264), km 110, Bairro Itinga, 18052-78, Sorocaba, São Paulo, Brazil [correspondence: Marcus V. Brandão O. <puerabio@gmail.com>].
² Universidade Federal da Paraíba, Departamento de Sistemática e Ecologia, Programa de Pós-Graduação em Zoologia, CEP 58059-900, João Pessoa, Paraíba, Brazil.
³ Ciências Biológicas pela Universidade Federal do Tocantins, Tocantins, Brazil.
⁴ Campus de Araguaina, R. Paraguai s/n (esquina com Urixamas), 77838-824, Araguaina, Brazil.
⁵ Campus de Porto Nacional, Rua 03, Quadra 17, Lote 11, s/n, Setor Jardim dos Ipês, 77500-000, Porto Nacional, Brazil.

Recibido 7 mayo 2014.
Aceptado 8 agosto 2014.

Editor asociado: D Flores

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ABSTRACT.

While described in the early twentieth century, Gracilinanus emiliae is still one of the least known taxa of its genus, with fewer than 20 specimens in scientific collections. In Brazil, only 2 specimens are known from the vicinity of Belém, Pará, and 2 specimens were recently reported from Amapá. We report here 2 new localities records for this country, which represent a significant range extension in the distribution of this marsupial. The new records corroborate the fact that G. emiliae inhabit primary lowland rain forest and it is present in great portion of the Amazonian border.

RESUMO.

Novos registros do elusivo marsupial Gracilinanus emiliae (Didelphimorphia, Didelphidae) da Bacia Amazônica Brasileira e uma extensão de distribuição para a espécie.

Embora descrito no início do século XX, Gracilinanus emiliae ainda é um dos táxons menos conhecidos de seu gênero, com menos de 20 espécimes em coleções científicas. No Brasil, apenas 2 espécimes são conhecidos das proximidades de Belém, Pará, e dois espécimes recentemente relatados do Amapá. Relatamos aqui 2 novos registros em localidades deste país, o que representa um aumento significativo na distribuição deste marsupial. Os novos registros corroboram o fato de que G. emiliae habita terras baixas da floresta tropical primária e está presente em grande parte da fronteira amazônica.

Key words: Amazonia; Brazil; Distribution extension; Rare marsupial.

Palavras chave: Amazônia; Brasil; Extensão de distribuição; Marsupial raro.

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Marsupials are a diversified group of Neotropical mammals that encompasses almost a hundred species (Voss and Jansa, 2009). For several of these species, however, geographic range limits are still poorly known, even for taxa described in the early 20th century. This includes most species of the genus Gracilinanus, which is currently divided into 6 valid taxon: aceramarcae (Tate, 1931), agilis (Burmeister, 1854), dryas (Thomas, 1898), emiliae (Thomas, 1909), marica (Thomas, 1898), and microtarsus (Wagner, 1842).

These small opossums are arboreal animals restricted to forested habitats in South America, including Brazil, where 3 species are known to occur: G. agilis in the moist and dry forests of central Brazil, G. microtarsus in the Atlantic Forest, and G. emiliae in lowland Amazon rainforest (Creighton and Gardner, 2008). The former 2 species are relatively common in museum collections (Voss and Jansa, 2009) and their geographic ranges, as well as their taxonomic status, have received considerable attention in recent years (Costa et al., 2003; Geise and Astua, 2009; Loss et al., 2011; Faria et al., 2013), whereas G. emiliae has been largely overlooked (but see Voss et al., 2009).

While it was described more than 100 years ago, G. emiliae is currently one of the least known species of the genus, with fewer than 20 specimens housed in scientific collections, and "data deficient" status in the IUCN Red List (Brito et al., 2008) and the Brazilian list of threatened species (Chiarello et al., 2008). Until recently, the species was known from only the northern Amazon basin (Voss et al., 2001); however, Voss et al. (2009) reported a record for Nuevo San Juan, Peru, extending its known geographic range by 950 km and indicating that it may be more widely distributed than was originally thought.

In Brazil, some of the records of G. emiliae from the Amazon region were derived from the erroneous identification of juvenile specimens of Marmosa lepida and from Hyladelphis kalinowskii (for details see Voss et al., 2001, 2009, respectively). Two cytogenetic studies reported the occurrence of G. emiliae in the Cerrado savanna of Goiás state, Brazil (Carvalho et al., 2002; Pereira et al., 2008). However, most specimens reported by Carvalho et al. (2002)-deposited in the Museu Nacional, Rio de Janeiro-actually belong to the genus Cryptonanus (A. P. Carmignotto, pers. comm.), while the single specimen analyzed by Pereira et al. (2008) is probably lost and, as the authors did not provide any morphological description, this record is doubtful and probably the reason why either record from Goiás are currently not included at the known distribution range of this species (see Creighton and Gardner, 2008; Voss et al., 2009). Finally, the specimen from Parque Nacional de Ubajara, Ceará-deposited in the Universidade Federal do Ceará, Ceará-, reported by Guedes et al. (2005) would need to be reevaluated. However, this individual is lost as there is no G. emilae specimen at the referred collection (Gurgel Filho and Langguth, in press). This specimen might be referent to "Marmosa" agricolai Moojen 1943, a typical taxon from the Caatinga biome and that was considered a junior synonym of G. emiliae by Gardner and Creighton (1989) but now is referred to the recently described genus Cryptonanus (Voss et al., 2005).

Given these considerations, the only reliable records of G. emiliae from Brazil are 2 specimens from the vicinity of Belém, in Pará state, and 2 recently reported from Amapá (Silva et al., 2013). The present study reports on material from 2 new Brazilian localities, which represent a significant extension of the known distribution of the species in this country.

One record is derived from a specimen deposited in the Museu de Zoologia da Universidade de São Paulo (MZUSP), and the other is from a live caught specimen. Measurements of the specimens are based on Voss et al. (2009). The museum specimen, MZUSP 11780, comprises a skin and skull (Fig. 1) from Fordlândia (3°50'S, 55°30'W) on the Tapajós River in Pará. This individual, a subadult male collected by A. M. Olalla in March, 1965, presents erupted, but unaligned third and fourth upper molars, consistent with Tribe's (1990) age class 5. While treated with caution, given the position of Voss et al. (2001, 2009) with regard to juveniles, this specimen is undoubtedly G. emiliae due to the presence of all the diagnostic characters of the species: reddish-brown dorsal fur, pure white-colored ventral fur, tail (LT) much longer than body (HBL) with LT/HBL ratio of 1.77 (Table 1), the presence of an anteromedial alisphenoid process on the auditory bullae, interorbital region with beaded supraorbital margins, and the absence of a maxillary fenestra (Fig. 1). The cranial measurements are also highly similar to those of the holotype, which we examined through photographs, and only slightly below the range of values recorded for adult G. emiliae specimens (Table 1).

Fig. 1. Dorsal (top, left), ventral (top, right), and lateral (bottom, middle) views of the skull and lateral view (bottom) of the mandible of a male Gracilinanus emiliae specimen (MZUSP 11780) from Tapajós River, Fordlândia, Pará, northern Brazil. Scale bar = 5 mm.

Table 1. Age, sex, weight (in g) and selected measurements (in mm) of the specimen (MZUSP 11780) of Gracilinanus emiliae recorded in Tapajós River, Fordlandia, Para, northern Brazil, and its comparison with the holotype (BMNH 93910) of the species and the range of 3 animals reported by Voss et al. (2009).

The second studied specimen was captured in Araguaina (7°11'S, 48°12'W), Tocantins state, which refers to an animal captured in a 20-liter pitfall trap during a herpetological survey in a lowland gallery forest in August, 2013. This is an adult individual (third upper premolar fully erupted) and was released, although its description refers clearly to G. emiliae: a very small murine opossum with smooth adult pelage; a narrow midrostral streak of pure orange fur contrasting with a unruffled reddish brown dorsal fur, and a tail distinctly much longer than the head-and-body (Fig. 2).

Fig. 2. Live-caught Gracilinanus emiliae specimen from Araguaina, Tocantins, Brazil.

This record from Tocantins represents the southeastern limit of the geographic range of G. emiliae (Fig. 3), an extension of approximately 610 km toward the southeastern limit of Amazonia, near a transitional area between Amazonia and Cerrado. Additionally, the record from Fordlândia further reinforce the apparent presence of G. emiliae at primary lowland rainforest, and its probably occurrence throughout most of the Amazon basin. Patton and Costa (2003) have suggested that Gracilinanus is absent from the Central Ama zon basin, and while none of the new records presented here contradicted this hypothesis, the record from Fordlândia does represent an approximation to the central basin. In addition, the spatial distribution of the known records, which stretch from Peru in the west to French Guiana in the northeast and Tocantins in the southeast, suggests that G. emiliae is widely dispersed throughout the basin.

Fig. 3. Recording localities for Gracilinanus emiliae: (1) Nuevo San Juan, Loreto, Peru; (2) Los Micos, Meta, Colombia; (3) Falcón, Venezuela; (4) Hato Mata de Bejuco, Monagas, Venezuela; (5) San Ignacio de Yuruaní, Bolívar, Venezuela; (6) Dadanawa, Upper Takutu-Upper Essequibo, Guyana; (7) Langamankondre, Marowijne, Suriname; (8) Paracou, French Guiana; (9) Igarape do Braço, FLONA Amapá, Amapá, Brazil; (10) Araguari River, Ferreira Gomes, Amapá, Brazil; (11) Belém, Para, Brazil (type locality); (12) Capim, Para, Brazil; (13) Fordlândia, Pará, Brazil; (14) Araguaina, Tocantins, Brazil. Compiled from Voss et al. (2009) and Silva et al. (2013); the stars indicate the new localities reported in this study.

Overall, the distribution pattern of Gracilinanus species indicates that the radiation of the genus was closely related to the distribution of forest formations in South America. Based on our current knowledge of the geographic range of G. emiliae, we believe that this and other Gracilinanus species may prove to occur not only in the central Amazon basin, but also in other poorly investigated forest areas of South America. The results of the present study further reinforce the paucity of our current knowledge on the diversity of Neotropical marsupials, and highlight the need for new inventories, especially in the central and western Amazon basin.

Acknowledgments.

The authors thank the curator, Mario de Vivo, and staff member, Juliana Gualda-Barros, for access to the specimens of the MZUSP Mammal Collection; to Stephen Francis Ferrari for the careful review of the manuscript; to Sergio Solari and one anonymous reviewer for advices on a previous version of the manuscript and to Ana Paula Carmignotto for advices and unpublished Cryptonanus information. Part of this work was supported through grants from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP - 2010/03969-4). PAR thanks CNPq for research stipends (501701/2013-3).

LITERATURE CITED

1. BRITO D, D ASTUA, D LEW, P SORIANO, and L MMONS. 2008. Gracilinanus emiliae, in: IUCN 2013 IUCN Red List of Threatened Species Version 20132 <www.iucnredlist.org> Downloaded on 02 April 2014.         [ Links ]

2. CARVALHO BA, LFB OLIVEIRA, AP NUNES, and MS MATTEVI. 2002. Karyotypes of nineteen marsupial species from Brazil. Journal of Mammology 83:58-70.         [ Links ]

3. CHIARELLO AG, LMS AGUIAR, R CERQUEIRA, FR MELO, FHG RODRIGUES, and VMF SILVA. 2008. Mamíferos Ameaçados de Extinção no Brasil. Pp. 680- 880, in: Livro Vermelho da Fauna Brasileira Ameaçada de Extinção (ABM Machado, GM Drummond, and AP Paglia, eds.). MMA, Brasília, Fundação Biodiversitas, Belo Horizonte, Biodiversidade.         [ Links ]

4. COSTA LP, YLR LEITE, and JL PATTON. 2003. Phylogeography and systematic notes on two species of gracile mouse opossums, genus Gracilinanus (Marsupialia, Didelphidae). Proceedings of the Biological Society of Washington 116:275-292.         [ Links ]

5. CREIGHTON GK and AL GARDNER. 2008. Genus Gracilinanus Gardner and Creighton, 1989. Pp. 43-50, in: Mammals of South America, Volume 1: Marsupials, Xenarthrans, Shrews and Bats (AL Gardner, ed.). The University of Chicago Press, Chicago.         [ Links ]

6. FARIA MB, FF NASCIMENTO, JA OLIVEIRA, and CR BONVICINO. 2013. Biogeographic determinants of genetic diversification in the mouse opossum Gracilinanus agilis (Didelphimorphia: Didelphidae). Journal of Heredity 104:613-626.         [ Links ]

7. GEISE L and D ASTUA. 2009. Distribution extension and sympatric occurrence of Gracilinanus agilis and G. microtarsus (Didelphimorphia, Didelphidae), with cytogenetic notes. Biota Neotropica (Online Edição em Inglês) 9:269-276.         [ Links ]

8. GUEDES, PG, SSP DA SILVA, AR CAMARDELLA, MFG DE ABREU, DM BORGES-NOJOSA, JAG DA SILVA, and AA SILVA. 2000. Diversidade de mamíferos do Parque Nacional de Ubajara (Ceará, Brasil). Mastozoologia Neotropical 7:95-100.         [ Links ]

9. GURGEL FILHO NM and A LANGGUTH. In press. Pequenos Mamíferos do Ceará (Didelphimorphia, Chiroptera e Rodentia). Revista Nordestina de Biologia.         [ Links ]

10. LOSS A, LP COSTA, and YRL LEITE. 2011. Geographic variation, phylogeny and systematic status of Gracilinanus microtarsus (Mammalia: Didelphimorphia: Didelphidae). Zootaxa 2761:1-33.         [ Links ]

11. PATTON JL and LP COSTA. 2003. Molecular phylogeography and species limits in rainforest didelphid marsupials of South America. Pp. 63-81, in: Predators with pouches: The biology of carnivorous marsupials (ME Jones, CR Dickman, and M Archer, eds.). CSIRO Press, Melbourne.         [ Links ]

12. PEREIRA NP, K VENTURA, MCS JÚNIOR, DM SILVA, Y YONENAGA-YASSUDA, and KCM PELLEGRINO. 2008. Karyotype characterization and nucleolar organizer regions of marsupial species (Didelphidae) from areas of Cerrado and Atlantic Forest in Brazil. Genetics and Molecular Biology 31:887-892.         [ Links ]

13. SILVA CR, ACM MARTINS, IJ CASTRO, E BERNARD, EM CARDOSO, D SANTOS LIMA, R GREGORIN, RV ROSSI, AR PERCEQUILLO, and KC CASTRO. 2013. Mammals of Amapá State, Eastern Brazilian Amazonia: A revised taxonomic list with comments on species distributions. Mammalia 77:1-16.         [ Links ]

14. VOSS RS and SA JANSA. 2009. Phylogenetic relationships and classification of didelphid marsupials, an extant radiation of New World metatherian mammals. Bulletin of the American Museum of Natural History 322:1-177.         [ Links ]

15. VOSS RS, DW FLECK, and SA JANSA. 2009. On the diagnostic characters, ecogeographic distribution, and phylogenetic relationships of Gracilinanus emiliae (Didelphimorphia: Didelphidae: Thylamyini). Mastozoología Neotropical 16:433-443.         [ Links ]

16. VOSS RS, DP LUNDE, and SA JANSA. 2005. On the contents of Gracilinanus Gardner and Creighton, 1989, with the description of a previously unrecognized clade of small didelphid marsupials. American Museum Novitates 3482:1-34.         [ Links ]

17. VOSS RS, DP LUNDE and NB SIMMONS 2001 The mammals of Paracou, French Guiana: a Neotropical rainforest fauna Part 1 Nonvolant species. Bulletin of the American Museum of Natural History 263:1-236.         [ Links ]