First paleoparasitological record of acanthocephalan eggs from Northwestern Patagonia (Late Holocene, Argentina)

Protozoan parasites of birds from the Tremembé formation (Oligocene of the Taubaté Basin), São Paulo, Brazil

OBJECTIVE

To analyze the presence of protozoan parasites in bird coprolites from the Tremembé Formation (Oligocene of the Taubaté Basin).

MATERIALS

Twenty avian coprolites embedded in pyrobituminous shale matrices.

METHODS

Samples were rehydrated and subjected to spontaneous sedimentation.

RESULTS

Paleoparasitological analyses revealed oocysts compatible with the Eimeriidae family (Apicomplexa) and one single Archamoebae (Amoebozoa) cyst.

CONCLUSIONS

The present work increases the amount of information about the spread of infections throughout the Cenozoic Era and reveals that the Brazilian paleoavifauna played an important role in the Apicomplexa and Amoebozoa life cycles.

SIGNIFICANCE

This is the first record of protozoans in avian coprolites from the Oligocene of Brazil. These findings can help in the interpretation of phylogenies of coccidian parasites of modern birds, as certain taxonomic characters observed in the Oligocene Protozoa characterize monophyletic groups in current molecular phylogenetic analyses.

LIMITATIONS

None of the oocysts were sporulated; therefore, it is not possible to identify the morphotypes to genus or species.

SUGGESTIONS FOR FURTHER RESEARCH

Our results create new perspectives related to biogeographic studies of the parasitic groups described and may improve the understanding of the temporal amplitude of parasitic evolutionary relationships between Protozoans and birds.

Vertebrates as uninfected disseminators of helminth eggs and larvae

The passive dispersal of non-mobile organisms by vertebrates (zoochory) is a common mechanism used to explain their often widespread distribution. Transport occurs either internally via the vertebrate digestive tract (endozoochory), or externally be adhering to skin, feathers or fur (ectozoochory), and its success is due to both physiological and ecological factors associated with the disseminating 'hosting' animal. Helminth eggs and larvae are generally non-mobile stages that are largely dependent on the movement of another animal, typically a host, for geographical dissemination. Studies on the zoochory of helminths by vertebrates are extensive and particularly long-standing, stretching back to the 19th century, although this literature is often overlooked when considering the biogeography of parasites. This review assesses the potential of helminths to be dispersed passively by zoochory examining evidence from both laboratory and field studies. The physiological dynamics of the vertebrate intestines and skin surface as hostile environments, as well as the characteristics of eggs and larvae which may facilitate successful transport are evaluated. The various mechanisms of helminth endo- and ectozoochory are presented and the likelihood of long-distance dispersal determined. It is concluded that zoochory is a potentially important means of disseminating parasites.

Parasites in micromammal fecal pellets throughout the Late Holocene ("Cueva Peligro" paleontological site, Patagonia, Argentina)

Parasite remains in micromammal fecal pellets collected from the paleontological site "Cueva Peligro" (CP 43°40'18"S, 66°24'52"W), Chubut Province, Argentina, were examined. The samples were obtained from two grids, dated between 1220 ± 70¹⁴C yr B.P. to modern dates. Fecal pellets were whole processed, rehydrated, homogenized, and examined via light microscopy. Eggs of parasites found were measured and photographed. Fecal pellets belong to one or more insectivore to omnivore unidentified micromammal species, possibly sigmodontine rodents. A high number of helminthes species was recorded (11 species), eight nematodes, two anoplocephalid cestodes and one acanthocephalan species. The sigmodontine-parasite relationship varied throughout the studied period and between studied grids. This is the first time that Gongylonema sp. and Syphacia sp. are reported from ancient times from Patagonia. The obtained results contribute to the knowledge of parasite assemblages associated to native South American sigmodontine rodents and the zoonoses present in the area throughout the lasts 1200 years.