RESUMO

Lymphomas are malignant neoplasms of the hematopoietic system arising from lymphocytes with highly variable biologic behavior. B-cell small lymphocytic lymphoma (B-SLL) is a non-Hodgkin lymphoma infrequently described in domestic and wild animals. The present study describes a case of B-SLL in a free-ranging adult male Arctocephalus australis in Brazil. The main necropsy findings included poor body condition, generalized lymphadenomegaly, severe and diffuse splenomegaly, and multiple, white to yellow nodules in the kidneys and small intestine. Histologically, these organs were partially or totally effaced by neoplastic small lymphocytes arranged in sheets, with moderate anisocytosis and anisokaryosis and a low mitotic count. These cells diffusely immunolabeled for CD79α and CD20, and were negative for CD3. A diagnosis of multicentric B-SLL was established and to the authors' knowledge, it has not been previously described in this genus.

Assuntos

RESUMO

Pinnipeds found across islands provide an ideal opportunity to examine the evolutionary process of population subdivision affected by several mechanisms. Here, we report the genetic consequences of the geographic distribution of rookeries in Galapagos fur seals (GFS: Arctocephalus galapagoensis) in creating population structure. We show that rookeries across four islands (nine rookeries) are genetically structured into the following major groups: 1) a western cluster of individuals from Fernandina; 2) a central group from north and east Isabela, Santiago, and Pinta; and possibly, 3) a third cluster in the northeast from Pinta. Furthermore, asymmetric levels of gene flow obtained from eight microsatellites found migration from west Isabela to Fernandina islands (number of migrants Nm = 1), with imperceptible Nm in any other direction. Our findings suggest that the marked structuring of populations recovered in GFS is likely related to an interplay between long-term site fidelity and long-distance migration in both male and female individuals, probably influenced by varying degrees of marine productivity.

RESUMO

Marine debris, in particular plastic debris and debris related to fishing activities, have an impact on marine mammals and seabirds. In marine-coastal species such as otariids, we can detect the incidence of these interactions through land-based observations. In this study, we recorded and described interactions between marine debris and the otariids Arctocephalus australis and Otaria byronia in a natural protected area in Peru, according to age class categories. Between 2016 and 2020, we recorded 151 animals that were directly impacted and/or were observed interacting with marine debris. Residual collars from fishing gear, ropes, plastic bags and unidentified material were recorded. Direct interactions with debris at colonies (e.g., plastic bags) were also recorded, as well as animals evidenced interacting with hooks. The age class category and species with the highest number of individuals impacted by residual collars were adult female A. australis and subadult male O. byronia. Single-use plastics were the most commonly bitten/moved waste by animals in the reserve. In the case of hooks, these were mostly lodged in the mouths of otariids. Our results highlight the importance of continuing to promote segregation at source, as well as the correct disposal of waste, locally and globally, to mitigate impacts on marine fauna.

Assuntos

RESUMO

Adenoviruses are medium size nonenveloped viruses with a trend of coevolution with their hosts. We surveyed South American fur seals (Arctocephalus australis) and Humboldt penguins (Spheniscus humboldti) for adenoviruses at two sites from 2009 to 2012. Despite the common pattern of host specificity, some of the adenoviruses in our study were present in samples from unexpected host species. We identified mastadenoviruses, aviadenoviruses, and siadenoviruses in A. australis from Peru and Chile and in S. humboldti from Peru. The El Niño Southern Oscillation (ENSO) significantly reduces the productivity of the Humboldt upwelling system, which can change trophic and other ecological interactions, facilitating exposure to new pathogens. One aviadenovirus was detected in both the penguins and the fur seals, an interclass distance. This finding occurred only during the 2009 ENSO and not in 2010 or 2012. Further studies of viral diversity in sites with high-density mixed species populations are necessary to better understand viral evolution and the effect of environmental change on viral evolution and host specificity.

Assuntos

RESUMO

Sympatric species evolve mechanisms to avoid competition and coexist. In the Humboldt Current System (HCS), populations of South American sea lions (SASL, Otaria byronia) and South American fur seals (SAFS, Arctocephalus australis) fluctuate mostly due to ENSO events and prey availability. We evaluate population trajectories of Peruvian sympatric otariids and discuss mechanisms for competition and/or resource limitation. For this purpose, we analyzed population trajectories of SASL and SAFS in a sympatric breeding site in Punta San Juan, Peru between 2001 and 2019. Wavelet analysis was used to extract trends and derivatives to estimate rates and turning points. Age-class proportions and biomass times series were constructed from weekly counts and evaluated. Both populations show a growth phase and subsequent decline. SAFS started to decline ~2.25 years before and at a rate 1.5 times faster than SASL. Decrease in juvenile age-class suggests that resource limitation is the main contributing factor for current population decline.

Assuntos

RESUMO

OBJECTIVES: Here, we present the first record of stable colonies of the South American fur seal (Arctocephalus australis), in an area where their presence has never been documented (hereafter distribution gap), as well as an update of the current distribution range of the species in central Chile. RESULTS: A national synoptic aerial census of pinnipeds was performed during the austral summer of 2019 on the Chilean coast. An additional aerial census was conducted in the same area during the austral spring of 2019 as well as a maritime census during the austral summer of 2020. The data showed the presence of South American fur seals in central Chile within their well-known distribution gap. The total abundance was registered in three colonies where fur seals were sighted: one non-breeding colony, Punta Topocalma (summer 2019: mean = 46 ± 3; spring 2019: mean = 9 ± 1); and two breeding colonies, Punta Curaumilla (summer 2019: mean = 595 ± 7; spring 2019: mean = 45 ± 4; summer 2020: mean = 744 ± 5) and Isla Santa María (summer 2019: mean = 246 ± 6). Specifically, we suggest that it is crucial to elucidate the origin of the described settled colonies, and to determine whether there has been an augment in the distribution range from either the northern population, the southern population, or both simultaneously.

Assuntos

RESUMO

South American fur seals (Arctocephalus australis) are believed to reach the coast of Rio Grande do Sul (RS) through sea currents. They live in colonies and are frequently found resting on the beach. However, it is also common to find dead pinnipeds on beaches, sharing the environment with humans, domestic animals and other wild species on the coast and facilitating the transmission of pathogens. In the present study, a metagenomic approach was applied to evaluate the viral diversity in organs of fur seals found deceased along the coast of the state of RS, southern Brazil. The lungs and spleens of 29 animals were collected, macerated individually, pooled separately (one pool for lungs and another for spleens) and sequenced using the Illumina MiSeq platform. Sequences more closely related to members of the Anelloviridae and Circoviridae families were detected. Nine putative new species of anellovirus and one putative new genus, named Nitorquevirus, were described. Additionally, the circovirus sequences found in the lungs of A. australis have a common ancestor with PCV3, a proposed swine pathogen. Our study expanded the knowledge about viral communities in pinnipeds and could be useful for monitoring new viruses and potential viral sharing among wildlife, domestic animals, and humans.

Assuntos

RESUMO

We studied the diet of non-breeding male Antarctic fur Seals Arctocephalus gazella (Peters, 1875) at two different localities of the South Shetland Islands: Stranger Point, King George Island/Isla 25 de Mayo and Duthoit Point, Nelson Island, by the analysis of 65 faecal samples collected in February 2012. Overall, Antarctic krill Euphausia superba (Dana, 1850) and fish were the main prey taxa followed by penguins and cephalopods. Myctophids were dominant among fish; Gymnoscopelus nicholsi (Gilbert, 1911) was the most important prey species at both sampling sites, followed by Electrona antarctica (Gunther, 1878) at Stranger Point and by the nototheniid Pleuragramma antarctica (Boulenger, 1902) at Duthoit Point. The relative similarity found in the dietary composition of fur seals from both locations suggest they might have been sharing common feeding areas. Our results were compared with those reported in the literature for different localities of the South Shetland Islands and the Scotia Sea region. The absence of formerly harvested demersal notothenioid species in the diet of fur seals may reflect the negative impact that commercial fisheries had on some fish populations and supports the importance of implementing long-term monitoring studies on the feeding habits of A. gazella in the area.(AU)

Se estudió la dieta de ejemplares macho no reproductivos de lobo fino antártico, Arctocephalus gazella (Peters, 1875) en dos localidades de las Islas Shetland del Sur: Cabo Funes/Punta Stranger, Isla 25 de Mayo / Isla Rey Jorge y Punta Duthoit, Isla Nelson; por medio del análisis de 65 muestras de materia fecal colectadas en Febrero de 2012. En general, el krill antártico Euphausia superba (Dana, 1850) y los peces fueron los taxa presa más consumidos, seguidos por pingüinos y cefalópodos. Entre los peces, los mictófidos fueron dominantes; Gymnoscopelus nicholsi (Gilbert, 1911) fue la especie más importante en ambos apostaderos, seguido por Electrona antarctica (Gunther, 1878) en Punta Stranger y por el nototénido Pleuragramma antarctica (Boulenger, 1902) en Punta Duthoit. La similitud hallada en la composición dietaria de los agrupamientos de lobo estudiados sugiere áreas de alimentación en común. Nuestros resultados fueron comparados con aquellos reportados en la literatura para diferentes localidades de las Islas Shetland del Sur y la región del Mar de Scotia. La ausencia de especies de nototenoideos demersales históricamente diezmadas en la dieta del lobo fino podría estar reflejando el impacto negativo que las pesquerías comerciales han tenido sobre algunas poblaciones de peces y enfatizar la necesidad de realizar un monitoreo a largo plazo de los hábitos alimentarios de A. gazella en el archipiélago de las Islas Shetland del Sur.(AU)

Assuntos

RESUMO

We studied the diet of non-breeding male Antarctic fur Seals Arctocephalus gazella (Peters, 1875) at two different localities of the South Shetland Islands: Stranger Point, King George Island/Isla 25 de Mayo and Duthoit Point, Nelson Island, by the analysis of 65 faecal samples collected in February 2012. Overall, Antarctic krill Euphausia superba (Dana, 1850) and fish were the main prey taxa followed by penguins and cephalopods. Myctophids were dominant among fish; Gymnoscopelus nicholsi (Gilbert, 1911) was the most important prey species at both sampling sites, followed by Electrona antarctica (Gunther, 1878) at Stranger Point and by the nototheniid Pleuragramma antarctica (Boulenger, 1902) at Duthoit Point. The relative similarity found in the dietary composition of fur seals from both locations suggest they might have been sharing common feeding areas. Our results were compared with those reported in the literature for different localities of the South Shetland Islands and the Scotia Sea region. The absence of formerly harvested demersal notothenioid species in the diet of fur seals may reflect the negative impact that commercial fisheries had on some fish populations and supports the importance of implementing long-term monitoring studies on the feeding habits of A. gazella in the area.

Se estudió la dieta de ejemplares macho no reproductivos de lobo fino antártico, Arctocephalus gazella (Peters, 1875) en dos localidades de las Islas Shetland del Sur: Cabo Funes/Punta Stranger, Isla 25 de Mayo / Isla Rey Jorge y Punta Duthoit, Isla Nelson; por medio del análisis de 65 muestras de materia fecal colectadas en Febrero de 2012. En general, el krill antártico Euphausia superba (Dana, 1850) y los peces fueron los taxa presa más consumidos, seguidos por pingüinos y cefalópodos. Entre los peces, los mictófidos fueron dominantes; Gymnoscopelus nicholsi (Gilbert, 1911) fue la especie más importante en ambos apostaderos, seguido por Electrona antarctica (Gunther, 1878) en Punta Stranger y por el nototénido Pleuragramma antarctica (Boulenger, 1902) en Punta Duthoit. La similitud hallada en la composición dietaria de los agrupamientos de lobo estudiados sugiere áreas de alimentación en común. Nuestros resultados fueron comparados con aquellos reportados en la literatura para diferentes localidades de las Islas Shetland del Sur y la región del Mar de Scotia. La ausencia de especies de nototenoideos demersales históricamente diezmadas en la dieta del lobo fino podría estar reflejando el impacto negativo que las pesquerías comerciales han tenido sobre algunas poblaciones de peces y enfatizar la necesidad de realizar un monitoreo a largo plazo de los hábitos alimentarios de A. gazella en el archipiélago de las Islas Shetland del Sur.

Assuntos

RESUMO

RESUMEN Se estudió la dieta de ejemplares macho no reproductivos de lobo fino antártico, Arctocephalus gazella (Peters, 1875) en dos localidades de las Islas Shetland del Sur: Cabo Funes/Punta Stranger, Isla 25 de Mayo / Isla Rey Jorge y Punta Duthoit, Isla Nelson; por medio del análisis de 65 muestras de materia fecal colectadas en Febrero de 2012. En general, el krill antártico Euphausia superba (Dana, 1850) y los peces fueron los taxa presa más consumidos, seguidos por pingüinos y cefalópodos. Entre los peces, los mictófidos fueron dominantes; Gymnoscopelus nicholsi (Gilbert, 1911) fue la especie más importante en ambos apostaderos, seguido por Electrona antarctica (Gunther, 1878) en Punta Stranger y por el nototénido Pleuragramma antarctica (Boulenger, 1902) en Punta Duthoit. La similitud hallada en la composición dietaria de los agrupamientos de lobo estudiados sugiere áreas de alimentación en común. Nuestros resultados fueron comparados con aquellos reportados en la literatura para diferentes localidades de las Islas Shetland del Sur y la región del Mar de Scotia. La ausencia de especies de nototenoideos demersales históricamente diezmadas en la dieta del lobo fino podría estar reflejando el impacto negativo que las pesquerías comerciales han tenido sobre algunas poblaciones de peces y enfatizar la necesidad de realizar un monitoreo a largo plazo de los hábitos alimentarios de A. gazella en el archipiélago de las Islas Shetland del Sur.

ABSTRACT We studied the diet of non-breeding male Antarctic fur Seals Arctocephalus gazella (Peters, 1875) at two different localities of the South Shetland Islands: Stranger Point, King George Island/Isla 25 de Mayo and Duthoit Point, Nelson Island, by the analysis of 65 faecal samples collected in February 2012. Overall, Antarctic krill Euphausia superba (Dana, 1850) and fish were the main prey taxa followed by penguins and cephalopods. Myctophids were dominant among fish; Gymnoscopelus nicholsi (Gilbert, 1911) was the most important prey species at both sampling sites, followed by Electrona antarctica (Gunther, 1878) at Stranger Point and by the nototheniid Pleuragramma antarctica (Boulenger, 1902) at Duthoit Point. The relative similarity found in the dietary composition of fur seals from both locations suggest they might have been sharing common feeding areas. Our results were compared with those reported in the literature for different localities of the South Shetland Islands and the Scotia Sea region. The absence of formerly harvested demersal notothenioid species in the diet of fur seals may reflect the negative impact that commercial fisheries had on some fish populations and supports the importance of implementing long-term monitoring studies on the feeding habits of A. gazella in the area.

RESUMO

Lungworms are a common finding in seals and fur seals around the world. However, from existing records, the biogeographical distribution of filaroid helminths appears to be restricted, and these parasites are endemic in only certain areas and species, mainly in the Northern Hemisphere. The occurrence of infection in pinniped species in the Southern Hemisphere is scarce. The objective of this work is to verify the prevalence of lungworms in Arctocephalus australis in waters off the southern coast of Brazil. Twenty subadult specimens of A. australis found recently dead on the southern coast of Brazil were necropsied and their lungs were examined. Parasitic cysts were found in only one specimen (prevalence of 5%). The helminths were morphologically identified as Parafilaroides normani (Metastrongyloidea: Filaroididae). This helminth species has been reported in pinnipeds from Australia, New Zealand and South Africa. This is the first record of P. normani in A. australis and for the western South Atlantic, providing additional data regarding the biogeographic distribution of the parasite.

Assuntos

RESUMO

The protozoans Toxoplasma gondii and Sarcocystis spp. (Sarcocystidae: Apicomplexa) affect a wide variety of vertebrates. Both have been reported to infect pinnipeds, with impacts on health ranging from inapparent to fulminant disease and death. However, little is known regarding their infections and associated pathology in South American pinnipeds. We used histological techniques to survey for the presence of T. gondii and Sarcocystis spp. in 51 stranded pinnipeds from Brazil. Immunohistochemical and molecular assays were employed in those cases consistent with Sarcocystidae infection. T. gondii cysts were detected in the central nervous system and heart of a South American fur seal Arctocephalus australis, associated with meningoencephalitis, myocarditis and endocarditis, and confirmed by immunohistochemistry. Additionally, this animal presented Sarcocystis sp. cysts in brain and heart tissues. Four additional specimens-2 Subantarctic fur seals A. tropicalis, an Antarctic fur seal A. gazella and another South American fur seal-presented intrasarcoplasmic cysts compatible with Sarcocystis spp. in muscle samples. There was no inflammation associated with the Sarcocystis spp. tissue cysts and all cysts were negative for S. neurona immunohistochemistry. The B1 gene of T. gondii was amplified in the 5 pinnipeds infected by Sarcocystidae protozoans. To our knowledge, this is the first report of toxoplasmosis in wild South American pinnipeds and of Sarcocystis spp. in South American fur seals. Detection of terrestrial parasites in aquatic mammals could be an indicator of their presence in the marine environment.

Assuntos

RESUMO

The tissues and parasites collected from Peruvian fur seals (Arctocephalus australis) and South American sea lions (Otaria byronia) found dead at Punta San Juan, Peru were examined. The respiratory mite, Orthohalarachne attenuata infected 3 out of 32 examined fur seals and 3 out of 8 examined sea lions, however caused moderate to severe lymphohistiocytic pharyngitis only in fur seals. Hookworms, Uncinaria sp, infected 6 of the 32 examined fur seals causing variable degrees of hemorrhagic and eosinophilic enteritis. This parasite caused the death of 2 of these pups. In fur seals and sea lions, Corynosoma australe and Contracaecum osculatum were not associated with significant tissue alterations in the intestine and stomach respectively. Respiratory mites and hookworms have the potential to cause disease and mortality among fur seals, while parasitic infections do not impact significatively the health of sea lions at Punta San Juan, Peru.

Assuntos

RESUMO

During five reproductive seasons, we documented the presence, extent and origin of perineal wounds in South American fur seal pups (Arctocephalus australis) on Guafo Island, Northern Chilean Patagonia. The seasonal prevalence of perineal wounds ranged from 5 to 9%, and new cases were more common at the end of the breeding season (February), when pups were on average two months old and were actively expelling hookworms (Uncinaria sp). Histologically, wounds corresponded to marked ulcerative lymphoplasmacytic and histiocytic dermatitis with granulation tissue and mixed bacterial colonies. In 2015 and 2017, kelp gulls (Larus dominicanus) and dolphin gulls (Leucophaeus scoresbii) were observed picking and wounding the perineal area of marked pups. This behaviour occurred more frequently after the pups' defecation, when sea gulls engaged in consumption of pups' faeces. The affected pups usually had moderate to marked hookworm infections along with bloody diarrhoea and anaemia. Pups with severe wounds (23% of affected animals) had swollen perineal areas and signs of secondary systemic bacterial infection. We propose that seagulls on Guafo Island have learned to consume remains of blood and parasites in the faeces of pups affected by hookworm infection, causing perineal wounds during this process. We conclude that this perineal wounding is an unintentional, occasional negative effect of an otherwise commensal gull-fur seal relationship.

RESUMO

The complete mitochondrial DNA sequence of the South America fur seal (Arctocephalus australis) was obtained by a shotgun sequencing approach. The mitogenome is 16,372 bp in length and includes the genes coding for the two rRNA species (12S and 16S), 13 protein-coding genes, 22 transfer RNA genes, and a control region. The base composition is 33.0% for A, 26.7% for C, 26.1 for T and 14.2% for G, with an overall GC content of 40.9%. The description of this mitogenome will be useful for further phylogeny and genetic studies on Pinnipeds.

RESUMO

The establishment of clinical pathology baseline data is critical to evaluate temporal and spatial changes in marine mammal groups. Despite increased availability of studies on hematology and biochemistry of marine mammals, reference ranges are lacking for many populations, especially among fur seal species. During the austral summers of 2014 and 2015, we evaluated basic hematologic and biochemical parameters in clinically healthy, physically restrained South American fur seal ( Arctocephalus australis ) lactating females and 2-mo-old pups. We also assessed the temporal variation of hematology parameters on the pups during their first 2 mo of life. Reference ranges of lactating females were similar to those previously reported in other fur seal species. In the case of pups, reference ranges are similar to values previously reported in sea lion species. As expected, most biochemical and hematologic values differ significantly between adult females and pups. As in other otariids, South American fur seals pups are born with higher values of total red blood cells, hemoglobin, and packed cell volume, and lower numbers of total leukocytes, neutrophils, lymphocytes, and eosinophils. To the best of our knowledge, data on hematology reference values for South American fur seals has not been previously reported and is useful for continued health monitoring of this species, as well as for comparisons with other otariid groups.

Assuntos

RESUMO

In order to improve understanding of parasitism in South American pinnipeds, respiratory and gastrointestinal samples were collected from 12 Arctocephalus australis (South American fur seal), one Arctocephalus gazella (Antarctic fur seal), and one Otaria flavescens (South American sea lion). Ova and larvae were microscopically identified from fecal samples and respiratory secretions collected from live A. australis undergoing rehabilitation at Centro de Recuperação de Animais Marinhos (CRAM-FURG) in Rio Grande, Rio Grande do Sul, Brazil during June-July 2012. Adult parasites were collected from the lungs and gastrointestinal tracts of animals that died while undergoing treatment or were found dead along the southern Brazil coast. Parasites were identified by polymerase chain reaction and DNA sequencing, microscopic examination, comparison with keys, and histologic examination of tissues. Lung parasites of the Parafilaroides genus (Metastrongyloidea, Filaroididae) were identified at necropsy in both A. australis and A. gazella and gastrointestinal parasites were found in all three species of pinniped studied. Gastrointestinal parasites identified in A. australis included the nematodes Contracaecum sp. and Pseudoterranova cattani, the cestodes Adenocephalus pacificus (previously Diphyllobothrium pacificum), one from the Tetrabothridae family and one undetermined, and the acanthocephalans Corynosoma sp. and Bolbosoma sp.; from A. gazella the nematode Contracaecum sp. and the acanthocephalan Corynosoma sp.; and from O. flavescens the acanthocephalan Corynosoma sp. Ova from fecal samples from A. australis represent ascarid nematodes, Parafilaroides sp., Adenocephalus pacificus, acanthocephalans, and an egg determined either to be a trematode or pseuophyllidean cestode. With limited information surrounding parasitism, these findings are an important contribution to knowledge of the health of Southern Hemisphere pinnipeds.

Assuntos

RESUMO

The Peruvian population of the South American fur seal ( Arctocephalus australis ) is a distinct evolutionarily significant unit that is endangered. One of the largest rookeries for this species in Peru is located within the Punta San Juan marine protected area (15°22'S, 75°12'W). To better understand the current health status of this population, exposure to 10 pinniped pathogens was evaluated in adult female fur seals (n=29) via serology and polymerase chain reaction (PCR) techniques in November 2010. The results suggest this population is naïve to canine and phocine distemper viruses (serum neutralization test), five Leptospira interrogans serovars (microscopic agglutination test), and Brucella canis (card test). Indirect fluorescent antibody testing for Toxoplasma gondii , Neospora caninum , and Sarcocystis neurona was also uniformly negative. PCR testing of nasal swabs using previously described Mycoplasma spp. primers was positive in 37.9% (11/29) of samples. One animal was positive via card test for Brucella abortus , whereas 53.7% (15/28) were positive or suspect using a marine Brucella competitive enzyme-linked immunosorbent assay. Antibody to phocine herpesvirus-1 (PHV-1) was identified in 85.7% (24/28) of the sampled population by serum neutralization testing. Overall, exposure to Mycoplasma spp., Brucella spp., and PHV-1 was observed, but results demonstrated low to no exposure to many key pinniped pathogens. The expansion of human populations, agriculture, and industry along the Peruvian coast may lead to increased pathogen exposure from human, domestic, and wild animal sources. The naïve nature of this key population of South American fur seals raises concerns about potential risk for disease outbreaks.

Assuntos

RESUMO

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)

Assuntos

RESUMO

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)

Assuntos