Cyphoderia ampulla (Cyphoderiidae: Rhizaria), a tale of freshwater sailors. The causes and consequences of ecological transitions through the salinity barrier in a family of benthic protists

An investigation into the morphological variation and ecological-environmental range of Cyphoderia compressa: A case study of Scottish material

Cyphoderia compressa has only been described from supralittoral environments, as a psammobiont, with salinities from 1.33 to 36.00 ‰. Other Cyphoderia species such as those in the C. ampulla species complex are more ecologically and environmentally widespread, occurring as free-living individuals within water bodies or in association with vegetation, and over a wider salinity range, including freshwater. We postulate that C. compressa may not be as restricted in terms of its environmental or ecological distribution. To this end, we examined a variety of water and sediment samples from Scottish localities, ranging from supralittoral to inland freshwater environments. The Scottish material occurs as a psammobiont within supralittoral beach sands and is newly recorded within sands from freshwater to brackish stream sections and along the margin of the freshwater Loch Lomond. It is also recorded from freshwater to brackish settings as part of the stream and pond water biota, associated biofilm and vegetative material. Test morphology is more variable than previously appreciated, including those with a papillate fundus, and many that are not as laterally compressed as typified by the species. Differences in plate morphology and size were also noted, as well as a novel arcuate cross-cutting ridged cement structure, that is restricted to C. compressa.

Phylogenomic insights into the historical biogeography, character-state evolution, and species diversification rates of Cypripedioideae (Orchidaceae)

Cypripedioideae (slipper orchids; Orchidaceae) currently consist of ∼200 herbaceous species with a strikingly disjunctive distribution in tropical and temperate regions of both hemispheres. In this study, an updated phylogeny with representatives from all five cypripedioid genera was presented based on maximum likelihood and Bayesian inference of plastome and low-copy nuclear genes. Phylogenomic analyses indicated that each genus is monophyletic, but some relationships (e.g., those among Cypripedium sects. Acaulia, Arietinum, Bifolia, Flabellinervia, Obtusipetala and Palangshanensia) conflict with those in previous studies based on Sanger data. Cypripedioideae appeared to have arisen in South America and/or the adjacent Qinghai-Tibet Plateau and Hengduan Mountains ∼35 Mya. We inferred multiple dispersal events between East Asia and North America in Cypripedium, and between mainland Southeast Asia and the Malay Archipelago in Paphiopedilum. In the Americas, divergences among four genera (except Cypripedium) occurred around 31-20 Mya, long before the closure of the Isthmus of Panama, indicating the importance of long-distance dispersal. Evolutionary patterns between morphological and plastome character evolution suggested several traits, genome size and NDH genes, which are likely to have contributed to the success of slipper orchids in alpine floras and low-elevation forests. Species diversification rates were notably higher in epiphytic clades of Paphiopedilum than in other, terrestrial cypripedioids, paralleling similar accelerations associated with epiphytism in other groups. This study also suggested that sea-level fluctuations and mountain-building processes promoted the diversification of the largest genera, Paphiopedilum and Cypripedium.

Their fates intertwined: diversification patterns of the Asian gliding vertebrates may have been forged by dipterocarp trees

The repeated evolution of gliding in diverse Asian vertebrate lineages is hypothesized to have been triggered by the dominance of tall dipterocarp trees in the tropical forests of Southeast Asia. These dipterocarp forests have acted as both centres of diversification and climatic refugia for gliding vertebrates, and support most of their extant diversity. We predict similarities in the diversification patterns of dipterocarp trees and gliding vertebrates, and specifically test whether episodic diversification events such as rate shifts and/or mass extinctions were temporally congruent in these groups. We analysed diversification patterns in reconstructed timetrees of Asian dipterocarps, the most speciose gliding vertebrates from different classes (Draco lizards, gliding frogs and Pteromyini squirrels) and compared them with similar-sized clades of non-gliding relatives (Diploderma lizards, Philautus frogs and Callosciurinae squirrels) from Southeast Asia. We found significant declines in net-diversification rates of dipterocarps and the gliding vertebrates during the Pliocene-Pleistocene, but not in the non-gliding groups. We conclude that the homogeneity and temporal coincidence of these rate declines point to a viable ecological correlation between dipterocarps and the gliding vertebrates. Further, we suggest that while the diversification decay in dipterocarps was precipitated by post-Miocene aridification of Asia, the crises in the gliding vertebrates were induced by both events concomitantly.

Deconstructing Difflugia: The tangled evolution of lobose testate amoebae shells (Amoebozoa: Arcellinida) illustrates the importance of convergent evolution in protist phylogeny

Protists, the micro-eukaryotes that are neither plants, animals nor fungi build up the greatest part of eukaryotic diversity on Earth. Yet, their evolutionary histories and patterns are still mostly ignored, and their complexity overlooked. Protists are often assumed to keep stable morphologies for long periods of time (morphological stasis). In this work, we test this paradigm taking Arcellinida testate amoebae as a model. We build a taxon-rich phylogeny based on two mitochondrial (COI and NADH) and one nuclear (SSU) gene, and reconstruct morphological evolution among clades. In addition, we prove the existence of mitochondrial mRNA editing for the COI gene. The trees show a lack of conservatism of shell outlines within the main clades, as well as a widespread occurrence of morphological convergences between far-related taxa. Our results refute, therefore, a widespread morphological stasis, which may be an artefact resulting from low taxon coverage. As a corollary, we also revise the groups systematics, notably by emending the large and highly polyphyletic genus Difflugia. These results lead, amongst others, to the erection of a new infraorder Cylindrothecina, as well as two new genera Cylindrifflugia and Golemanskia.