Phylogeny and Character Evolution of the Neotropical Fern Genus Cyclodium (Dryopteridaceae)

Abstract— Cyclodium is a neotropical fern genus with 13 species, most of them distributed in the Amazonian lowlands, particularly in the Guianan region and along the border with the Andes. It belongs to the polybotryoid clade of Dryopteridaceae, being unique within this clade by a combination of characters related to rhizome growth, leaf dimorphism, anastomosing venation, and peltate indusia. Here we present a molecular phylogenetic hypothesis for Cyclodium resulting from Bayesian and maximum likelihood analyses, using molecular sequences of five plastid markers. We also map 12 morphological characters and habit onto the resulting trees. Our results support Cyclodium as monophyletic and sister to Polybotrya. The presence of peltate indusia is the main character distinguishing Cyclodium. Our results also suggest that plesiomorphic conditions in Cyclodium are free venation (vs. anastomosing), creeping rhizomes (vs. erect or decumbent), highly dissected laminae (vs. 1-pinnate), monomorphic sterile and fertile fronds (vs. dimorphic), and pinnatifid apices (vs. conform).

The Taming of Psidium guajava: Natural and Cultural History of a Neotropical Fruit

Guava (Psidium guajava L., Myrtaceae) is a Neotropical fruit that is widely consumed around the world. However, its evolutionary history and domestication process are unknown. Here we examine available ecological, taxonomic, genetic, archeological, and historical evidence about guava. Guava needs full sunlight, warm temperatures, and well-distributed rainfall throughout the year to grow, but tolerates drought. Zoochory and anthropochory are the main forms of dispersal. Guava’s phylogenetic relationships with other species of the genus Psidium are unclear. A group of six species that share several morphological characteristics are tentatively accepted as the Psidium guajava complex. DNA analyses are limited to the characterization of crop genetic diversity within localities and do not account for possible evolutionary and domestication scenarios. A significant amount of archeological information exists, with a greater number and older records in South America than in Mesoamerica, where there are also numerous historical records. From this information, we propose that: (1) the guava ancestor may have originated during the Middle or Late Miocene, and the savannas and semi-deciduous forests of South America formed during the Late Pleistocene would have been the most appropriate ecosystems for its growth, (2) the megafauna were important dispersers for guava, (3) dispersal by humans during the Holocene expanded guava’s geographic range, including to the southwestern Amazonian lowlands, (4) where its domestication may have started, and (5) with the European conquest of the Neotropics, accompanied by their domestic animals, new contact routes between previously remote guava populations were established. These proposals could direct future research on the evolutionary and domestication process of guava.

Evolutionary Diversity Peaks at Mid-Elevations Along an Amazon-to-Andes Elevation Gradient

Elevation gradients present enigmatic diversity patterns, with trends often dependent on the dimension of diversity considered. However, focus is often on patterns of taxonomic diversity and interactions between diversity gradients and evolutionary factors, such as lineage age, are poorly understood. We combine forest census data with a genus level phylogeny representing tree ferns, gymnosperms, angiosperms, and an evolutionary depth of 382 million years, to investigate taxonomic and evolutionary diversity patterns across a long tropical montane forest elevation gradient on the Amazonian flank of the Peruvian Andes. We find that evolutionary diversity peaks at mid-elevations and contrasts with taxonomic richness, which is invariant from low to mid-elevation, but then decreases with elevation. We suggest that this trend interacts with variation in the evolutionary ages of lineages across elevation, with contrasting distribution trends between younger and older lineages. For example, while 53% of young lineages (originated by 10 million years ago) occur only below ∼1,750 m asl, just 13% of old lineages (originated by 110 million years ago) are restricted to below ∼1,750 m asl. Overall our results support an Environmental Crossroads hypothesis, whereby a mid-gradient mingling of distinct floras creates an evolutionary diversity in mid-elevation Andean forests that rivals that of the Amazonian lowlands.

Phylogenetic placement of the spider genus Taczanowskia (Araneae:Araneidae) and description of a new species from Ecuador

The genus Taczanowskia Keyserling, 1879 is one of the rarest groups of spiders in the orb-weaving family Araneidae, with only five species described and 17 specimens cited in publications. Our study provides new insights into the evolutionary relationships and diversity of Taczanowskia. Using morphological data, we tested the evolutionary relationships of the genus within the family Araneidae and propose the first phylogenetic hypothesis depicting the relationships among species of Taczanowskia. Our results place Taczanowskia as sister to Mastophora Holmberg, 1876, and confirm the monophyly of Taczanowskia. We describe the first species of Taczanowskia from Ecuador, collected at a Waorani community on the River Curaray basin, Amazonian lowlands of Ecuador. The new species can be easily diagnosed from all other species of Taczanowskia by having two tubercles in the opisthosoma; a distinct patchy dark–light colouration pattern with dark spots concentrated towards the anterior margin and on the lateral tips; small bundles of white setae forming a reticulum across the dorsal part of the opisthosoma, and the first two femora thick but lacking teeth on the margin. ZooBank registration: urn:lsid:zoobank.org:pub:46B8C1F7-A474-4DC3-90BC-940F84AC099D

Magnolia napoensis (subsect. Talauma, Magnoliaceae): a new species from the Amazonian lowlands of Ecuador and Peru

Magnolia napoensis, a new species from the Amazonian lowlands of Ecuador and Peru is described and illustrated. This species belongs to subsection Talauma; it is similar to M. rimachii in leaf shape but differs from the latter in being taller with a larger diameter and having fewer lateral leaf veins, more numerous hypsophylls, larger flowers, longer outer petals, more numerous stamens and fruits ovoid and ribbed vs. subglobose and smooth. The new species differs from M. neillii by its leaves with fewer lateral veins, glabrous petioles and terminal internodes, more numerous hypsophylls, fewer stamens and ovoid fruits of smaller size, with fewer carpels. Magnolia napoensis is assessed as endangered (EN B2ab(iii)) in accordance with the IUCN criteria.

Convergence and divergence in anti-predator displays: A novel approach to quantitative behavioural comparison in snakes

Animals in nature use diverse strategies to evade or deter their predators, including many vivid behavioural displays only qualitatively described from field encounters with natural predators or humans. Within venomous snake mimicry, stereotyped anti-predator displays are suggested to be a critical component of the warning signal given by toxic models and thus under strong selection for independent convergence in mimetic species. However, no studies have systematically quantified variation in snake anti-predator displays across taxonomically broad clades to test how these behaviours evolve across species within a phylogenetic comparative methods framework. Here we describe a new, high-throughput approach for collecting and scoring snake anti-predator displays in the field that demonstrates both low observer bias and infinite extension across any species. Then, we show our method’s utility in quantitatively comparing the behaviour of 20 highly-divergent snake species from the Amazonian lowlands of Peru. We found that a simple experimental setup varying simulated predator cues was very successful in eliciting anti-predator displays across species and that high-speed videography captured a greater diversity of behavioural responses than described in the literature. We also found that although different display components evolve at different rates with complicated patterns of covariance, there is clear evidence of evolutionary convergence in anti-predator displays among distantly related elapid coral snakes and their colubrid mimics. We conclude that our approach provides new opportunity for analyses of snake behaviour, kinematics, and the evolution of anti-predator signals more generally, especially macroevolutionary analyses across clades with similarly intractable behavioural diversity.