Herpetofauna from an Atlantic Forest fragment in São Paulo, Brazil

Habitat loss via urbanization is a cause of decline for reptile and amphibian species around the world. The Atlantic Forest is the second largest rainforest of South America and holds one of the most extraordinary herpetofauna in the world, even after decades of fragmentation. The Parque Estadual das Fontes do Ipiranga (PEFI) is one of the most important remnants of Atlantic Forest inside the city of São Paulo (Brazil), but its herpetofauna richness has not been studied. Between 2011 and 2014, we carried out a herpetofaunal inventory in the PEFI and made notes on habitat use by using pitfall traps with drift fences combined with acoustic and visual encounter surveys. We also collected data from opportunistic encounters and historical information from scientific collections. We found that the PEFI harbors 22 native species of anurans, 24 native species of reptiles, and three exotic species of reptiles. Also, through surveying scientific collections, we found three species of amphibians and one of the snakes that were detected in the past but were not detected during our survey. The composition of amphibian species in the PEFI is similar to proximal small urban and periurban Atlantic Forest fragments, but its species richness is higher than these fragments even when compared to areas with similar or larger size. In conclusion, the highly urban PEFI supports considerable herpetofaunal diversity in comparison with other regional areas and our data reinforce the necessity of conserving this and other urban forest fragments through strategic management across the Atlantic Forest.

Notes on the hyperossified pumpkin toadlets of the genus Brachycephalus (Anura: Brachycephalidae) with the description of a new species

Four species of pumpkin toadlets are currently recognized by the extreme condition of hyperossification in the skull and vertebral column within the genus Brachycephalus. In addition to their larger body size, relative to other congeneric species, Brachycephalus darkside, Brachycephalus ephippium, Brachycephalus garbeanus, and Brachycephalus margaritatus share remarkable osteological features, such as the large paravertebral plates forming an ornamented dorsal bone shield, visible through the integument. We add to the current knowledge of this group by analyzing its diversity and describing a new hyperossified species from some important Atlantic Forest remnants in southeastern Brazil, including those bordering São Paulo, the largest and most populous city in South America. The new species is diagnosed by a combination of morphological, osteological, and bioacoustic characters, with further evidence of mtDNA sequences to confirm its distinction from the other congeners. The parotic and paravertebral bone plates externally bordered with a rough and pale contour can readily distinguish the new species from the other hyperossified species within Brachycephalus. The new species is widely distributed along the Serra do Mar mountain range, including the regionally named Serra de Paranapiacaba, in elevations from 700 to 1000 m above sea level (a.s.l.), in the central coast of the state of São Paulo, southeastern Brazil. We discuss valuable morphological characters within this group of species, reinforce the need for further studies, and highlight the relevance of protected areas for biodiversity conservation in metropolitan regions.

The tadpole of Hylodes caete (Anura: Hylodidae), an endemic Atlantic rainforest Torrent frog of Brazil.

The genus Hylodes Fitzinger currently comprises 26 species of Torrent frogs, organized into four morphological taxonomic groups (Heyer 1982; Frost 2020): Hylodes glaber, H. lateristrigatus, H. mertensi, and H. nasus groups. Hylodes lateristrigatus is the most speciose group, comprising today 20 known species (Frost 2020). Nested in this group, a clade has been recovered based on molecular evidence, gathering the only four Hylodes species that are known to have males with nuptial thumb tubercles (de Sá et al. 2015; Malagoli et al. 2017). This well-supported clade includes H. phyllodes Heyer Cocroft, Hylodes fredi Canedo Pombal, H. pipilans Canedo Pombal, and H. caete Malagoli, de Sá, Canedo Haddad. Among these four Torrent frogs, tadpoles are unknown only for the most recently described H. caete (see tadpole descriptions in Heyer et al. 1990; Laia et al. 2010; Nogueira-Costa et al. 2019). With important taxonomic and conservation implications for the family Hylodidae (Laia Rocha 2012), we describe here the tadpole of Hylodes caete, a species endemic to the crests and slopes of Serra do Mar, State of São Paulo, southeastern Brazil (Malagoli et al. 2017). The present description is particularly important because, in its type-locality, H. caete occurs in sympatry and syntopy with H. phyllodes (Malagoli et al. 2017).

Low resistance to chytridiomycosis in direct-developing amphibians.

Host-generalist pathogens sporadically infect naive hosts, potentially triggering epizootics. The waterborne fungus Batrachochytrium dendrobatidis (Bd) is linked to declines of hundreds of amphibian species with aquatic larvae. Although several population declines and extinctions attributed to Bd have been reported among cryptic species undergoing direct development away from water, epidemiological studies focused on these terrestrial frogs are lacking. Our field data support that terrestrial direct-developing hosts are less exposed to Bd during their ontogeny than species with aquatic larvae, and thus they might lack adaptive responses against waterborne chytrids. Using controlled laboratory experiments, we exposed wild-caught amphibian species with terrestrial and aquatic life histories to Bd and found that direct developers showed more rapid increases in infection loads and experienced higher mortality rates than species with aquatic larvae. Our findings provide novel information about host responses to generalist pathogens and specifically show that our focal direct developing species have low resistance to Bd infections. Finally, our results underscore that we should not ignore Bd as a potential threat to direct developing species simply because they are less exposed to Bd in nature; instead future amphibian conservation plans should include efforts to safeguard hundreds of direct-developing amphibian species globally.