Albinism in Brazilian common opossums (Didelphis aurita)

Albinism has been sporadically recorded in Virginia opossums (Didelphis virginiana) in the United States and Mexico, but records of pigmentation disorders in other Didelphis spp. are rare. The Brazilian common opossum (Didelphis aurita) is a cat-sized nocturnal omnivorous marsupial that inhabits Atlantic and Araucaria forests in South America. A litter of five young Brazilian common opossums was rescued at Espírito Santo state, southeast Brazil, of which two were albinos (one male, one female) and the remaining had normal pigmentation (three males). The two albinos had a complete lack of integumentary and retinal pigmentation, representing the first recorded cases of albinism in this species (and the first record in a Didelphis sp. other than the Virginia opossum).

Eimeria spp. (Apicomplexa: Eimeriidae) in Didelphis aurita Wied-Neuwied, 1826 (Didelphimorphia: Didelphidae) and description of a new species infecting this opossum

Didelphis aurita Wied-Neuwied, 1826 is a marsupial well adapted to anthropogenic activity and commonly found in urban areas of Brazil. Among the gastrointestinal parasites found in this opossum, protozoa of the genus Eimeria are frequently detected. This study investigated the biodiversity of Eimeria species infecting D. aurita in Southeastern Brazil, and provides morphological data on a newly discovered species of Eimeria. From January to June 2019, 43 D. aurita were captured, and their fecal samples were collected and evaluated by salt flotation; positive samples were allowed to sporulate in 2.5% potassium dichromate (K2Cr2O7), and detailed morphological measurements were performed to determine the species present. Thirty-two of forty-three (74.4%) opossums were infected with from one to five Eimeria spp. Four of the eimerians were described and named previously by others: Eimeria auritanensis, Eimeria caluromydis, Eimeria gambai, and Eimeria philanderi. Additionally, sporulated oocysts of a species new to science were detected. Oocysts of this new Eimeria species are spheroidal to subspheroidal, 21.7 × 20.7 (20-23 × 19-23), length/width (L/W) ratio 1.05, with a highly refractile polar granule, but lacking a micropyle and oocyst residuum. Sporocysts are ovoidal, 10.6 × 8.0 (9-12 × 7-9), L/W ratio 1.3, with a small, Stieda body and a sporocyst residuum of diffuse granules. Of the infected opossums, 5/32 (16%) were infected with only one Eimeria sp., 6/32 (19%) with two, 15/32 (47%) with three, 5/32 (16%) with four and 1/32 (3%) with five Eimerians.

Mamíferos não-voadores e ataques por cães domésticos em Morro Branco, Vargem Alta, ES

A redução populacional de mamíferos é causada principalmente pela perda e fragmentação de habitats, em especial, no contexto da Mata Atlântica, além da caça e a introdução de espécies exóticas em ambientes naturais, como os cães domésticos. Este estudo teve como objetivo realizar um levantamento de mamíferos não-voadores e avaliar o impacto predatório de Canis lupus familiaris sobre esta comunidade, em uma área selecionada para a implantação da futura Área de Proteção Ambiental (APA) 'Morro Branco', no Sítio Morro Branco, Vargem Alta - ES, realizado entre fevereiro de 2015 e fevereiro de 2016. O levantamento ocorreu por meio de busca ativa por vestígios (pegadas, fezes e carcaças) e uso de armadilhas de gaiola e fotográficas. Foram registrados 18 táxons, distribuídos em 6 ordens e 10 famílias, totalizando 84 indivíduos. Três táxons foram classificados como abundantes (CTA): Nasua nasua (26%), Canis lupus familiaris (15%) e Didelphis aurita (14%). Quatro espécies constam como ameaçadas: Puma yagouaroundi, Puma concolor, Mazama Bororo e Callithrix flaviceps. A técnica que registrou maior número de táxons foi o registro de carcaças de animais predados, com 9 táxons, seguido de registro visual, com 8 espécies e uso de armadilha fotográfica, com 7 espécies. O registro de carcaças de animais predados por Canis lupus familiaris foi o método com maior número de registros exclusivos, como Puma yagouaroundi, Galisctis cuja e Mazama bororo, registrados apenas desta forma. 13 animais foram encontrados abatidos, com marcas de mordidas evidentes, correspondendo a 18% do total. As espécies mais predadas foram Didelphis aurita, Dasypus novemcinctus e Mazama americana. Canis lupus familiaris apresentou alta Abundância Relativa (15,48%) na área, tornando-se um fator de risco para a conservação de espécies ameaçadas, como Puma yagouaroundi e Puma concolor, que além de ataques, podem sofrer por competição. É urgente a tomada de ações conservacionistas e a elaboração de um plano de manejo para a criação da Área de Proteção Ambiental (APA) 'Morro Branco', tendo em vista a influência de animais exóticos sobre a fauna nativa, implicando diretamente na conservação da biodiversidade.

A successful multiple litter adoption in a nursing southern black-eared opossum, Didelphis aurita (Didelphimorphia, Didelphidae)

Adoption by an alloparent of an offspring or a litter occurs in at least eight mammal orders, but is rare in marsupials, and was never confirmed in opossums. Here we report the first unequivocal and documented successful event of alloparental adoption of two distinct litters by a single captive female Southern Black-eared Opossum Didelphis aurita (Didelphimorphia, Didelphidae). The female, still nursing her biological litter, accepted and nursed the two offered litters. All three litters were raised simultaneously, and the female cared for and displayed protective behaviour indistinctively of the biological or adopted pups. She was kept captive until released along with her biological litter, which was weaned and fled independently, and the two adoptive litters clinging on her back. This event sheds additional light on the little known social and maternal behaviour of opossums, suggesting it is possibly more complex than originally thought.

A case of polymelia associated with syndactyly in Didelphis aurita (Wied-Neuwied, 1826)

In January 2018, a young male of Didelphis aurita (Wied-Neuwied, 1826), the Brazilian common opossum, was admitted for veterinary evaluation at the Recovery Clinic of Wild Animals of Estácio de Sá University, CRAS, in Rio de Janeiro, Brazil, due to the presence of a partially duplicated right hind limb. After x-ray evaluation, polymelia associated with syndactyly was diagnosed. The images revealed the following alterations on the right limb: single femur with increased diameter, two tibiae, two fibulae and absence of hallux. The observed malformations were restricted to the hind right limb, which remains functional. This is the first report of such anomalies in an individual of Didelphis aurita.