The Congo clawless otter (<i>Aonyx congicus</i>)  Mustelidae: Lutrinae): a review of its systematics, distribution and conservation status

Jacques, Hélène; Veron, Géraldine; Alary, Franck; Aulagnier, Stéphane

doi:10.1080/15627020.2009.11407450

Cited by 6 publications

(7 citation statements)

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“…Asian small-clawed otters, unlike giant river otters and North American river otters, are hand-oriented predators [ 27 – 28 ] and should not require high velocity jaws to capture prey. This expectation was supported by the morphometric analysis.…”

Section: Discussionmentioning

confidence: 99%

“…Based on diet alone, it is likely that spotted-necked otters ( Hydrictis maculicollis ) are also mouth-oriented predators, since they feed primarily on fish, frogs, and amphibians [ 25 ]. In contrast, sea otters ( Enhydra lutris ), Asian small-clawed otters ( Aonyx cinerea ), and African clawless otters ( Aonyx capensis ) primarily feed on invertebrate prey [ 22 ] and are considered to be hand-oriented predators [ 23 , 26 – 27 ]. Although Asian small-clawed otters primarily feed on invertebrates, they do incorporate fish into their diets [ 26 ], as do some populations of sea otters [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

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Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae)

2015

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Variation in terrestrial mammalian skull morphology is known to constrain feeding performance, which in turn influences dietary habits and ultimately fitness. Among mustelids, otters have evolved two feeding specializations: underwater raptorial capture of prey (mouth-oriented) and capture of prey by hand (hand-oriented), both of which have likely associations with morphology and bite performance. However, feeding biomechanics and performance data for otters are sparse. The first goal of this study was to investigate the relationships between feeding morphology and bite performance among two mouth-oriented piscivores (Pteronura brasiliensis and Lontra canadensis) and two hand-oriented invertebrate specialists (Enhydra lutris and Aonyx cinerea). Since other vertebrate taxa that are mouth-oriented piscivores tend to possess longer skulls and mandibles, with jaws designed for increased velocity at the expense of biting capability, we hypothesized that mouth-oriented otters would also possess long, narrow skulls indicative of high velocity jaws. Conversely, hand-oriented otters were expected to possess short, blunt skulls with adaptations to increase bite force and crushing capability. Concomitant with these skull shapes we hypothesized that sea otters would possess a greater mandibular bluntness index, providing for a greater mechanical advantage compared to other otter species investigated. A second goal was to examine morphological variation at a finer scale by assessing variation in cranial morphology among three sea otter subspecies. Since diet varies among these subspecies, and their populations are isolated, we hypothesized that the magnitude of mandibular bluntness and concomitant mechanical advantage, as well as occlusal surface area would also vary within species according to their primary food source (fish versus hard invertebrates). Functional expectations were met for comparisons among and within species. Among species the phylogeny suggests a deeply rooted transition to alternative foraging types. Yet within foraging types alternative species were also strongly variable, suggesting either selective differences in the extent or nature of realized foraging mode, or an accumulation of non-adaptive changes during the long independent evolutionary history. At the finest scale, variation among subspecies indicates that trophic adaptation occurred rapidly, making it interesting that we happened to find both deeply and shallowly-rooted transformations associated with diet type in otter species and subspecies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae)

2015

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“…The magnitude of morphological and genetic differentiation between the two Galictis species was similar to results reported by recent studies targeting the taxonomic status of other mustelid genera (e.g. Helgen et al ., 2008; Harding & Smith, 2009; Jacques et al ., 2009; del Cerro et al ., 2010). Our observed discrimination between the two clusters in both types of multivariate analysis (PCA and DFA) was almost perfect, with the exception of two male records of G. cuja [one from Rio Grande do Sul state, southern Brazil (MZUSP 1044), and another from the coast of Uruguay (MNHNA 2696)] that were located within the G. vittata cluster in the PCA (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Taxonomic revision of the genusGalictis(Carnivora: Mustelidae): species delimitation, morphological diagnosis, and refined mapping of geographical distribution

Bornholdt

Helgen

Koepfli³

et al. 2013

Zool J Linn Soc

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Although critical for enabling in-depth evolutionary, ecological, or conservation-orientated studies, taxonomic knowledge is still scarce for many groups of organisms, including mammals of the order Carnivora. For some of these taxa, even basic aspects such as species limits and geographical distribution are still uncertain. This is the case for the Neotropical mustelid genus Galictis, considered one of the least studied carnivoran genera in the Americas. To address this issue, we performed a comprehensive assessment of morphological and molecular characters to test the number of species within Galictis, and to characterize their distinctiveness and evolutionary history. In addition, we reviewed and consolidated the available information on the taxonomy of this genus, so as to provide a historical framework upon which we could interpret our data. Our analyses demonstrated that two Galictis species can be clearly delimited and diagnosed using metric and nonmetric morphological characters as well as DNA sequences from mitochondrial and nuclear gene segments. On the basis of this clarified species-level delimitation, we reassessed the geographical range of each Galictis taxon, identifying possible areas of sympatry between them. These results provide a solid taxonomic framework for Galictis, enabling the development of additional studies focusing on this poorly known taxon.

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“…For instance, the three African species that turned out to be highly exposed but also had a high sensitivity require climatic conditions that are not common in the biome currently occupied by the species; this results in restricted niche breadth along precipitation seasonality. In particular, habitat and food specialization of specific prey species of A. congicus (mainly earthworms) (Jacques et al 2009) might hinder its ability to withstand climate change in its current locations. Considering that many of the areas predicted to become newly suitable for this species in the future are also likely to experience a higher human footprint, this species is at risk of facing a rapid decline.…”

Section: Species' Vulnerability To Climate Change: Range Exposure Vsmentioning

confidence: 99%

More than range exposure: Global otter vulnerability to climate change

Cianfrani

Broennimann

Loy

et al. 2018

Biological Conservation

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Climate change impact on species is commonly assessed by predicting species' range change, a measure of a species' extrinsic exposure. However, this is only one dimension of species' vulnerability to climate change. Spatial arrangement of suitable habitats (e.g., fragmentation), their degree of protection or human disturbance, as well as species' intrinsic sensitivity, such as climatic tolerances, are often neglected. Here, we consider components of species' intrinsic sensitivity to climate change (climatic niche specialization and marginality) together with components of extrinsic exposure (changes in range extent, fragmentation, coverage of protected areas, and human footprint) to develop an integrated vulnerability index to climate change for world's freshwater otters. As top freshwater predators, otters are among the most vulnerable mammals, with most species being threatened by habitat loss and degradation. All dimensions of climate change exposure were based on present and future predictions of species distributions. Annual mean temperature, mean diurnal temperature range, mean temperature of the wettest quarter, precipitation during the wettest quarter, and precipitation seasonality prove the most important variables for otters. All species are vulnerable to climate change, with global vulnerability index ranging from-0,19 for Lontra longicaudis to-36,9 for Aonyx congicus. However, we found that, for a given species, climate change can have both positive and negative effects on different components of extrinsic exposure, and that measures of species' sensitivity are not necessarily congruent with measures of exposure. For instance, the range of all African species would be negatively affected by climate change, but their different sensitivity offers a more (Hydrictis maculicollis, Aonyx capensis) or less (Aonyx congicus) pessimistic perspective on their ability to cope with climate change. Also, highly sensitive species like the South-American Pteronura brasiliensis, Lontra provocax, and Lutra perspicillata might face no exposure to climate change. For the Asian Lutra sumatrana, climate change would instead lead to an increased, less fragmented, and more protected range extent, but the range extent would also be shifted into areas with higher human disturbances. Our study represents a balanced example of how to develop an index aimed at comparatively evaluating vulnerability to climate change of different species by combining different aspects of sensitivity and exposure, providing additional information on which to base more efficient conservation strategies.

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The Congo clawless otter (Aonyx congicus) Mustelidae: Lutrinae): a review of its systematics, distribution and conservation status

Cited by 6 publications

References 0 publications

Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae)

Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae)

Taxonomic revision of the genusGalictis(Carnivora: Mustelidae): species delimitation, morphological diagnosis, and refined mapping of geographical distribution

More than range exposure: Global otter vulnerability to climate change

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