Resumen en Inglés:

The syncranial osteology of Ceratophrys aurita, a largosized and characteristic anuran of southeastern Brazil, is described. The main osteological features and their resultant manifestations, as well as the exostosic dermal ornamentation and the specialized dentition clearly confirm this species as a terrestrial, fossorial and phragmotic type, with active predatory habits.

Resumen en Inglés:

Thoropa megatympanum, sp. n., is described from the Serra do Cipó, Minas Gerais, Southeastern Brasil. The new species is related to T. miliaris (Spix), from which it is readily distinguished by its smaller size, broader head, larger tympanum, shorter legs, and dorsal pattern mottled. The eggs and the tadpole are also described.

Resumen en Inglés:

Zelleriella ubatubensis, sp. n. is described. This species was found in the caecal region of the leptodactylid Thoropa miliaris from Ubatuba, SP, Brasil. The cell body has an irregular ellipsoid outline (145.9 µm ± 3.0 x 93.9 µm ± 24). The nucleus (16.7 µm ±0.3) has a fragmented nucleolar mass (more than nine nucleoli). Z. ubatubensis seems to be morphologically similar to Z. caryosoma and Z. foliacea but it differs from them by dimension, chromatin and host. A great number of the observed specimens contained Endamoeba paulista in their cytoplasm.

Resumen en Inglés:

Antwrens of the genus Myrmotherula (Formicariidae) are common members of mixed flocks in the understory of neotropical forest, but rarely follow army ants more than a few minutes as a flock passes. Antwrens that glean in open foliage (axillaris, longipennis) and ones that forage on dead foliage (fulviventris and relatives) apparently have to canvass large areas too rapidly to stay with slow-moving ants. Antwrens that glean low foliage of vertical seedlings (guttata, hauxwelli, gularis) can stay near ants only in such patches, despite close resemblance to sallying and hence less microhabitat-limited Hylophylax antbirds, some of which follow ants regularly.

Resumen en Inglés:

Hylophylax naevia of moderately dense forest undergrowth and H. punctulata of open swamp undergrowth tend to sally for arthropods in low foliage rather than sally to the ground among large ant-following antbirds. They and related Hypocnemoides melanopogon of swamp understory edges are also limited by their microhabitat niches in following ants. Myrmoderus ferrugineus and M. loricatus, ground-walking small antbirds seemingly derived from Hylophylax, follow ants infrequently, probably because ants, large ant-following birds, and predators would attack them if they did so.

Resumen en Inglés:

Phlegopsis erythroptera (Formicariidae) follows army ants regularly for flushed arthropods between the Andes and the Negro/Madeira Rivers. Mainly a bird of terra firme forests, it is interspecifically aggressive. Low numbers at ant swarms are probably due to low productivity of arthropods flushed by ants on weathered terra firme soils, or to high species diversity of subordinate but active ant-following competitors in upper Amazonia. Sexual dimorphism of young and female erythroptera is attributed to low numbers over ants, so that dispersed individuals avoid attacks by bright-plumaged adult males rather than bluff them out at close range. Phlegopsis, Skutchia, Rhegmatorhina, and Gymnopithys are related to and perhaps congeneric with Pithys; all follow ants and seem a group derived from birds related to Hylophylax.