Extant diversity of bryophytes emerged from successive post-Mesozoic diversification bursts.

Unraveling the macroevolutionary history of bryophytes, which arose soon after the origin of land plants but exhibit substantially lower species richness than the more recently derived angiosperms, has been challenged by the scarce fossil record. Here we demonstrate that overall estimates of net species diversification are approximately half those reported in ferns and ∼30% those described for angiosperms. Nevertheless, statistical rate analyses on time-calibrated large-scale phylogenies reveal that mosses and liverworts underwent bursts of diversification since the mid-Mesozoic. The diversification rates further increase in specific lineages towards the Cenozoic to reach, in the most recently derived lineages, values that are comparable to those reported in angiosperms. This suggests that low diversification rates do not fully account for current patterns of bryophyte species richness, and we hypothesize that, as in gymnosperms, the low extant bryophyte species richness also results from massive extinctions.

In ovum exposure to pesticides increases the egg weight loss and decreases hatchlings weight of Caiman latirostris (Crocodylia: Alligatoridae).

The increasing use of pesticides affects ecosystem health. Caiman latirostris is a South American species with ecological and physiological features that render it vulnerable to exposure to pesticides with endocrine disruptor's action. Our main objective was to test the effect of in ovum exposure to atrazine and endosulfan on the sex ratio of caiman hatchlings; however, we are also presenting unexpected findings regarding pesticide effects on egg weight loss during incubation and hatchlings relative weight. Caiman eggs were incubated under controlled temperature (30 and 33 degrees C) and humidity (>90%). They were treated with vehicle, 17 beta-estradiol (1.4ppm), atrazine (0.2ppm) and endosulfan (0.02; 2; 20ppm). Pesticides did not cause estrogen-like effects on sex determination. Greater egg weight loss was observed in eggs treated with atrazine and higher doses of endosulfan (2 and 20ppm) (p=0.0005). These pesticides also caused a reduction in hatchling fractional weight (p=0.0497). These effects might have a significant impact on caiman population dynamics.