We investigated trophic resource partitioning in seven syntopic anurans from low- and mid-elevation stream habitats of a tropical riparian ecosystem by utilising stomach content analysis (SCA) and stable isotope analysis (SIA). Our SCA data revealed dietary similarities, narrow trophic niche breadth, and low dietary niche overlap in Ansonia muelleri, Limnonectes magnus, Occidozyga laevis, Megophrys stejnegeri, Pulchrana grandocula, Sanguirana mearnsi, and Staurois natator which could be attributed to these anurans’ selection of available local prey items. We confirmed ant-specialisation (myrmecophagy) of the Mindanao island endemic bufonid A. muelleri based on our temporal SCA dietary data. Our SIA estimates of assimilation of potential prey sources confirmed that L. magnus, P. grandocula, and O. laevis are generalist predators, opportunistically feeding on locally abundant insect prey items. This study on trophic resource partitioning in syntopic anurans provides the first picture of trophic interactions, i.e., predation and competition in stream communities in tropical riparian zones of a watershed ecosystem in northeast Mindanao of the southern Philippines.

The epidemiology behind multi-host/multi-parasite systems is particularly interesting to investigate for a better understanding of the complex dynamics naturally occurring in wildlife populations. We aimed to approach the naturally occurring polyparasitism of gastrointestinal nematodes in a sympatric wild ruminant scenario present in south-east Spain. To this end, the gastrointestinal tract of 252 wild ruminants of four different species (red deer, Cervus elaphus; mouflon, Ovis aries musimon; Iberian ibex, Capra pyrenaica and fallow deer, Dama dama) were studied in Cazorla, Segura y Las Villas Natural Park (Andalusia, Spain). Of the analysed animals, 81.52% were positive for parasite infection and a total of 29 nematode species were identified. Out of these, 25 species were detected in at least two host species and 11 parasitized all ruminant species surveyed. The multi-host interaction between these nematodes and the four host species is discussed under the perspective of host family-based differences.

Climate change can cause geographic displacement of the ecological niche of a species, so that similar species that previously did not coexist could begin to face new interactions. Such geographic displacement and increased competition can also be exacerbated by anthropic intervention. Until less than 100 years ago, Vultur gryphus and Coragyps atratus did not coexist. Nowadays, possibly as a result of climate change, changes in the distributions of both species created areas where they are now sympatric. Through ecological niche modeling, we evaluated the possible effects that future scenarios of climate change and human influence would have on the distribution and sympatry between the two species. Our models predict that the current distribution of V. gryphus will be reduced between 18% and 24% by 2050 and between 21% and 32% by 2070. Additionally, they predict that the distribution of C. atratus will be reduced by 31–52% by the year 2050 and 15–60% by 2070. The two algorithms predict a reduction in the areas of sympatry. However, for the northern Andes the overlap between the two species will increase, reaching up to 70% in the year 2070. The distribution of C. atratus will move towards higher areas in the altitudinal gradient, and this will generate an increase in the current sympatry between both species. No clear trend was observed on the effect of human influences on the areas of overlap between the scenarios evaluated. The possible effects of climate change and anthropic intervention in future scenarios found in this study highlight the need to include these effects in future analyses and conservation programs of V. gryphus and other threatened vultures.

During the Early–Late Cretaceous transition, marine ecosystems in Eurasia hosted a diverse set of large predatory reptiles that occupied various niches. However, most of our current knowledge of these animals is restricted to a small number of bonebed-like deposits. Little is known of the geographical and temporal extent of such associations. The middle Albian – middle Cenomanian phosphorite-bearing succession exposed at Annopol, Poland produces numerous ichthyosaurian and plesiosaurian fossils. These are mostly isolated skeletal elements (e.g. teeth, vertebrae), but disarticulated partial skeletons and an articulated, subvertically embedded ichthyosaur skull are also available. The following taxa are identified: ‘Platypterygius’ sp., cf. Ophthalmosaurinae, Ichthyosauria indet., Polyptychodon interruptus, Pliosauridae indet., Elasmosauridae indet. and Plesiosauria indet. The large-sized ichthyosaur ‘Platypterygius’ and the pliosaurid Polyptychodon interruptus predominate within the upper Albian – middle Cenomanian deposits. The Annopol record, combined with data from England, France and western Russia, suggests that ‘Platypterygius’ and Polyptychodon interruptus formed a long-term, stable ecological sympatry in marine ecosystems of the European archipelago, at least during the Albian – middle Cenomanian. In addition, the marine reptile assemblage from Annopol is distinct from other Eurasian ecosystems in containing also elasmosaurids in its Albian portion.

Within southern Africa, the widely distributed four-striped mouse genus (Rhabdomys) is parasitized by, amongst others, the specific ectoparasitic sucking louse, Polyplax arvicanthis. Given the presence of significant geographically structured genetic divergence in Rhabdomys, and the propensity of parasites to harbour cryptic diversity, the molecular systematics of P. arvicanthis was investigated. Representatives of P. arvicanthis were sampled from Rhabdomys at 16 localities throughout southern Africa. Parsimony and Bayesian gene trees were constructed for the mitochondrial COI, 12S rRNA, 16S rRNA and nuclear CAD genes. Our findings support the existence of 2 genetic groups within P. arvicanthis separated by at least 25% COI sequence divergence, which is comparable to that observed among recognized Polyplax species. We therefore propose that these 2 genetic lineages probably represent distinct species and that the apparent absence of clear morphological differences may point to cryptic speciation. The 2 taxa have sympatric distributions throughout most of the sampled host range and also occasionally occur sympatrically on the same host individual. The co-occurrence of these genetically distinct lineages probably resulted from parasite duplication via host-associated allopatric divergence and subsequent reciprocal range expansions of the 2 parasite taxa throughout southern Africa.

Habitat use of Manta alfredi and M. birostris was assessed at 20 localities in the Indian and Pacific Oceans based upon 3328 photographic observations. Geographical relationships of the two species were scored as either microallopatry, microparapatry or microsympatry at each locality. Our study revealed a mosaic habitat occupancy by the two species within their macrosympatric range.

From May 1997 to July 1999, 24 gray foxes Urocyon cinereoargenteus were radio-marked and their fates monitored in a natural area of southern California to identify rates of survival and cause-specific mortality, and thus to assess population sustainability. Pup (0.4–1.0 years old) foxes had an 8-month (September–April) survival rate (0.34) that was lower than the 8-month (0.77) or 12-month (0.58) estimates for adult foxes. Interference competition was evident; 92% (11/12) of fox mortalities were the result of predation by sympatric coyotes Canis latrans or bobcats Felis rufus. Also, five of seven gray fox mortalities were outside of, or on the border of, the home range of the killed fox. Calculations indicated that the fox population would remain stable if survival of pups during their first 4 months of life was 0.68 (vs 0.75 for adults during these months and 0.58 for older pups for 4 other months). This seems reasonable, yet sympatric carnivores, mainly coyotes, clearly influence the gray fox population in southern California.

The level of genetic differentiation between anadromous and non-andromous trout (Salmo trutta L.) coexisting in a Norman river (Oir river) was examined at 15 microsatellites markers. Despite a large amount of variation, no genetic differentiation was found between forms. Four domesticated stocks were also genotyped with the same loci. Highly significant differences were found with natural samples allowing to exclude a recent stocking effect on the Oir population. We conclude that the resident and anadromous trout form a single naturally reproducing unit in this river system. However, this conclusion could reflect particular ecological or demographic conditions in the Oir basin and needs to be validated in other hydrographical and ecological contexts.

The diet of grey-headed albatrosses at Diego Ramírez was analysed and compared to that of the sympatric black-browed albatross. Diet composition was inferred from an analysis of prey hard parts present in 103 chick regurgitates obtained during breeding seasons 2000, 2001 and 2002. The squid Martialia hyadesi predominated in the diet samples in 2001 and 2002 (89% and 81% of reconstituted mass), but was absent from the 2000 samples. Reconstituted mean mass per sample in 2000 was significantly lower than in 2001 and 2002. Chick growth rate during 2000 was also the lowest recorded. This suggests that M. hyadesi plays an important role in the breeding performance of grey-headed albatrosses at Diego Ramírez. Low presence of M. hyadesi in grey-headed albatrosses' diet at South Georgia in 2000, a year with significant low breeding success, suggests ocean-wide processes affecting the availability of this prey to both populations simultaneously. Overlap in diet composition, and inferred feeding areas, between the sympatric albatross species at Diego Ramírez was minimal. Grey-headed albatrosses fed mainly on species associated with the Antarctic Polar Front, whereas black-browed albatrosses consumed benthopelagic species frequently caught in fishing operations in southern Chile.

Morphometric data were collected for 410 specimens of Pareledone turqueti and P. polymorpha caught around South Georgia. The two species differ in beak morphology and in the male hectocotylus. The species have similar appearances although there is a small but significant difference in the mantle length/body mass relationship for females, with P. polymorpha having a relatively longer mantle. There is no significant difference in the arm length/body mass relationship between species or sexes (p>0.05), except in the case of arm IV of females. There is an interspecific significant difference between sucker number on arms I and II of males, arms I–IV of females, and between hood length and mass of the buccal mass (p<0.05), with P. turqueti having relatively lower sucker numbers, a longer hood length and greater buccal mass mass. The beak of P. turqueti is similar to that of Eledone spp. but P. polymorpha has a small, fine beak with the rostral tip ending in an elongated, sharp point. Differences in beak and buccal mass suggest that these sympatric species occupy distinct trophic niches and that the differing morphology of the male hectocotylus is a factor in reproductive isolation.

Subantarctic Marion Island is one of the few localities where the congeneric albatrosses Phoebetria fusca and P. palpebrata breed sympatrically. Chicks of both species at Marion Island were induced to regurgitate their stomach contents after being fed. Liquid formed over half the diet by mass. Cephalopods occurred most frequently in both species' diets. In terms of mass, cephalopods formed the larger part of the diet of sooty albatrosses, whereas fish was more important to light-mantled sooty albatrosses. Crustaceans and birds were also recorded for both species. Squid of the families Onychoteuthidae, Histioteuthidae, Chiroteuthidae and Cranchiidae occurred most abundantly in both species. Most squid taken by both albatrosses were of species known to float after death, suggesting that scavenging plays an important role in the species' foraging behaviour. Light-mantled sooty albatrosses consumed more squid restricted to the south of the Antarctic Polar Front than did sooty albatrosses, supporting a trend to latitudinal segregation of the two species while foraging.

Although there has been extensive research on bottlenose dolphins (genus Tursiops), much controversy over the classification within this genus still exists. Even though many morphological variants occur, the prevailing view is for a single species, Tursiops truncatus (Montagu, 1821). To evaluate this view, two sympatric forms of bottlenose dolphins inhabiting Chinese waters were examined using multivariate statistical analyses of osteological data for two meristic and 18 cranial morphometric characters from 71 specimens. Cluster and principal components analyses revealed clear osteological separation of the two forms. Furthermore, the distributions of the total number of vertebrae and several proportions of cranial characters were non-overlapping between the two forms. These results provided strong evidence that the two sympatric forms of Tursiops in Chinese waters are isolated reproductively and do not support the current view of a monotypic genus. Classification functions of a discriminant analysis and a key of several characters were developed to help researchers identify unassigned specimens. Provisional names (T. truncatus and T. aduncus) were suggested, but a formal taxonomic revision of this genus is still required. However, regardless of the nomenclature, immediate amendments to all present wildlife conservation legislation are strongly urged.

Though most Xenopus species are polyploid and can be hybridized in the laboratory, natural hybridization seems to be restricted to hybrids of X. laevis laevis×X. gilli. A parapatric distribution pattern between X. l. laevis and X. muelleri seems to prevent interbreeding. We found X. l. laevis and X. muelleri living sympatrically in water bodies in the Republic of South Africa west of Kruger Park and report a natural hybrid of X. l. laevis×X. muelleri. Natural occurrence of such a hybrid has not been reported previously. The hybrid character was confirmed by analysis of its advertisement calls, which were intermediate between those of the parental species, by analysis of its serum albumin pattern, and by determination of the nuclear DNA content of its erythrocytes. The results indicate that this specimen is an F1 hybrid between X. l. laevis and X. muelleri. Backcrossing with both parental species indicated that the hybrid is sterile. It is discussed why sympatry between X. l. laevis and X. muelleri though possible might be rare.