The skin structures and their role in the thermoregulation of the South American fur seal (Arctocephalus australis).

The skin of the South American fur seal (Arctocephalus australis) is important for animal thermoregulation in both terrestrial and aquatic environments. Skin tissue samples were collected from A. australis for microscopic analysis and were related to anatomical references. The aim of this study was to describe the skin morphology, as well as to suggest the major anatomical regions and skin components involved in the thermoregulation of this species. Using light microscopy, the skin of six animals was examined based on histological, morphometric, and immunohistochemical criteria. Hair follicle morphology was examined using scanning electron microscopy. The skin was classified as either thick or thin based on its epidermal thickness. The thin epidermis regions had more abundant hair follicles, as well as high pigmentation, whereas the thick epidermis regions had very pigmented epidermal layers. Pigmentation of hair and skin is fundamental for protection against ultraviolet rays; moreover, hair is important in preventing abrasion, and provides an insulating layer against the external environment, which can be much colder than body temperature. Furthermore, the dermis is well vascularized, especially the superficial dermis. All regions of the skin have adaptations for maintaining the animal's condition in both terrestrial and aquatic environments. Among the studied regions, the interdigital region from hindflipper showed important morphological characteristics related to thermoregulation, such as having an epidermis of intermediate thickness, a dermis with a small number of hairs, a large amount of blood vessels, and sweat glands with large lumens, indicating that heat exchange in this region may be faster.

Ultrastructural aspects of the tongue in Magellanic Penguins Spheniscus magellanicus (Forster, 1781) / Aspectos ultraestruturais da língua de Pinguim-de-Magalhães Spheniscus magellanicus (Forster, 1781)

The tongue of birds presents diversified morphologic characteristics, related directly their feeding habits and may be adapted to food capture. Penguins of the Spheniscidae family are pelagic birds that are totally adapted to the marine environment. The objective of this study was to describe the morphology of the tongue in Magellanic penguins (Spheniscus magellanicus). In order to investigate these characteristics, six tongues of juvenile S . magellanicus were collected and their morphology analyzed macroscopically and microscopically. The tongue of the Magellanic penguin has a fusiform shape with a round apex that is narrower than the root, following the shape of the beak. The epithelium of the tongue of the Magellanic penguin showed to be stratified and very keratinized, with the presence of lingual papillae that showed a caudally inclined apex. The neighboring connective tissue showed absence of mucous glands. The cartilaginous skeleton was observed in the medial region of the tongue, extending from the base to the apex. The structure of the tongue of the Magellanic penguin showed to be similar to that of other penguin species, but also showed peculiar characteristics that were not observed in other bird families.

A língua das aves apresenta características morfológicas diversificadas, relacionados diretamente com seus hábitos alimentares e pode ser adaptado para a captura de alimentos. Os pinguins da família Spheniscidae são aves pelágicas totalmente adaptadas ao ambiente marinho. O objetivo deste estudo foi descrever a morfologia da língua de pinguins de Magalhães (Spheniscus magellanicus). Para investigar tais características, seis línguas de S. magellanicus juvenis foram coletados e sua morfologia analisada macro e microscopicamente. A língua do pinguim de Magalhães tem formato fusiforme com ápice arredondado e mais estreito em relação à raiz, acompanhando o formato do bico. O epitélio da língua do pinguim-de-Magalhães mostrou-se estratificado e muito queratinizado, com a presença de papilas linguais, com ápices voltados caudalmente. O tecido conjuntivo adjacente mostrou ausência de glândulas mucosas. Um esqueleto cartilaginoso, formado por cartilagem hialina, foi observado na região mediana da língua se estendendo da base até ápice. A estrutura da língua do pinguim Magellanic mostrou ser semelhante ao de outras espécies de pinguins, mas também apresentou características peculiares que não foram observados em outras famílias de aves.

Genital morphology of the male South American fur seal (Arctocephalus australis) and biological implications / Morfologia dos órgãos genitais do macho do Lobo marinho (Arctocephalus australis) e implicações biológicas

Male capacity for spreading genes to a great number of descendents and to determine population dynamics depend directly on the genital organs. Morphological studies in pinnipeds are scarce and the functional meaning of some characteristics has never been discussed. We hypothesized that Arctocephalus australis (A. australis) shows morphophysiological adaptations in order to guarantee the perpetuation of the species in the unique annual mating season. Seven males, dead from natural causes, had their genital organs collected and fixed for morphological description. Some features differ from other described mammalian males and are closely related to the biology and reproductive cycle of this species, as the scrotal epidermis, absence of glandular portion in the ductus deferens and spermatogenic epithelium suggest a recrudescent testis period. The corona glandis exhibits a singular arrangement: its erectile border looks like a formation of petals and its association with the os penis gives a "lily-flower" form to this region. We propose the name margo petaliformis to this particular erectile border of the corona glandis because of its similarity to a flower corola. The male genital organs of A. australis show morphological features compatible with adaptation to environment requirements and reproductive efficiency.(AU)

A capacidade do macho de espalhar seus genes a um grande número de descendentes e determinar a dinâmica populacional depende diretamente dos seus órgãos genitais. Estudos morfológicos em pinípedes são escassos e o significado funcional de algumas de suas características ecológicas ainda foi pouco discutido. Nossa hipótese é que Arctocephalus australis (A. australis) apresenta adaptações morfofisiológicas em seus órgãos genitais capazes de interagir com o meio e garantir a perpetuação da espécie que apresenta apenas uma época de acasalamento que ocorre uma vez a cada ano. Sete A. australis machos, mortos recentes por causas naturais, tiveram seus órgãos genitais coletados e fixados para a descrição macro, micro e ultraestrutural. Algumas características diferem de outros machos já descritos e estão intimamente relacionados com a biologia e ciclo reprodutivo da espécie, dentre elas podemos citar a alta queratinização da epiderme escrotal que pode se relacionar com as rotineiras lesões por atrito desta região nas pedras; a ausência da porção glandular do ducto deferente aqui descrita pela primeira vez, o epitélio espermatogênico sugere um período de testículo recrudescente. A glande apresenta um arranjo singular: a coroa da glande apresenta porção lateral de tecido esponjoso que são bordas livres com capacidade de intumescencia. O osso peniano se encontra no centro destas bordas e representa a extremidade mais distal do penis, levando consigo o óstio uretral externo. As bordas associadas ao osso peniano, dão uma forma de "Flor de lírio" a esta região. Utilizamos o nome margo petaliformis a margem erétil liliforme a particular morfologia da glande, pela sua semelhança a uma corola de flor. Os órgãos genitais masculinos de A. australis mostram características morfológicas compatíveis com uma adaptação aos requisitos ambientais e de eficiência reprodutiva.(AU)

Clareamento da melanina na epiderme do lobo-marinho-sul-americano e sua aplicação na imunohistoquímica enzimática / Bleaching of melanin in the epidermis of south American fur seal and its application on enzyme immunohistochemistry

O Lobo-marinho-sul-americano (Arctocephalus australis) é um mamífero marinho anfíbio distribuído ao longo da Costa do Atlântico e do Pacífico da América do Sul. Esta espécie está bem adaptada a diferentes habitats devido à morfologia dos membros em forma de nadadeira e de seu sistema tegumentar. Estudos imuno-histoquímicos são importantes para avaliar os mecanismos de adaptação da pele devido a diferencial expressão dos antígenos presentes no tecido dependendo da região da superfície corporal. Entretanto, sua epiderme altamente pigmentada (melanina) impede a visualização dos marcadores cromógenos utilizados na imunohistoquímica. Neste trabalho foi desenvolvido um método de clarear a melanina para permitir a visualização dos cromógenos sem alterar a afinidade antígeno-anticorpo para a imuno-histoquímica. A análise do índice do PCNA (proliferating cell nuclear antigen) na epiderme de A. australis, com diaminobenzidina (DAB) como cromógeno foi usada para testar o método. O clareamento da melanina permitiu obter o índice de proliferação celular na epiderme e evitar resultados falso-positivos sem afetar os resultados imuno-histoquímicos.

The South American fur seal (Arctocephalus australis) is an amphibious marine mammal distributed along the Atlantic and Pacific coasts of South America. The species is well adjusted to different habitats due to the morphology of its fin-like members and due to some adaptations in their integumentary system. Immunohistochemical studies are very important to evaluate the mechanisms of skin adaptation due the differential expression of the antigens present in the tissue depending of the region of the body surface. However, its strongly pigmented (melanin) epidermis prevents the visualization of the immunohistochemical chromogens markers. In this study a melanin bleaching method was developed aimed to allow the visualization of the chromogens without interfering in the antigen-antibody affinity for immunohistochemistry. The analysis of PCNA (proliferating cell nuclear antigen) index in the epidermis of A. australis by immunohistochemistry with diaminobenzidine (DAB) as chromogen was used to test the method. The bleaching of the melanin allowed to obtain the cell proliferation index in epidermis and to avoid false positive results without affecting the immunohistochemical results.

Serologic evidence of influenza A and B viruses in South American fur seals (Arctocephalus australis).

The aim of this work was to detect serologic evidence of influenza virus infections in South American fur seals (Arctocephalus australis) that inhabit the Uruguayan coast. In 29 of 37 serum samples that were analyzed, we identified antibodies to at least one of the following antigens: H1N1 (A/NewCaledonia/20/99), B/Beijing/184/93-like viruses, B/Hong Kong/330/01, and B/Sichuan/379/99 by means of the hemagglutination inhibition assay (HAI). Results confirmed that influenza A viruses circulate in marine mammals and also showed, for the first time, indirect evidence of influenza B infections in Arctocephalus australis.

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) from a false killer whale, Pseudorca crassidens (Cetacea: Delphinidae), stranded on the coast of Uruguay.

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) was found in the cranial air sinuses of a false killer whale, Pseudorca crassidens (Owen), stranded on the coast of Uruguay in 1999. Although this species has been reported once in P. crassidens from the North Atlantic, this is the first record for South America. A total of 920 specimens were obtained, of which 663 were females (body length: 4.34 +/- 0.45 cm) and 257 were males (2.99 +/- 0.18 cm). Morphometric details are presented for S. globicephalae in this host, which do not show significant differences from those parasitizing Globicephala melas (Traill), but are distinct from those parasitizing Peponocephala electra (Gray). The host's skull revealed loss of osseous mass with the disappearance of the left zygomatic arch, and the left jaw had three osseous fenestrations in the region related to the organ of acoustic reception. These lesions support the hypothesis that this infection, known as stenurosis, was related to the stranding.

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) from a false killer whale, Pseudorca crassidens (Cetacea: Delphinidae), stranded on the coast of Uruguay

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) was found in the cranial air sinuses of a false killer whale, Pseudorca crassidens (Owen), stranded on the coast of Uruguay in 1999. Although this species has been reported once in P. crassidens from the North Atlantic, this is the first record for South America. A total of 920 specimens were obtained, of which 663 were females (body length: 4.34 ± 0.45 cm) and 257 were males (2.99 ± 0.18 cm). Morphometric details are presented for S. globicephalae in this host, which do not show significant differences from those parasitizing Globicephala melas (Traill), but are distinct from those parasitizing Peponocephala electra (Gray). The host's skull revealed loss of osseous mass with the disappearance of the left zygomatic arch, and the left jaw had three osseous fenestrations in the region related to the organ of acoustic reception. These lesions support the hypothesis that this infection, known as stenurosis, was related to the stranding