How snow leopard gradually adapted to the extreme environments in Tibet remains unexplored due to the scanty fossil record in Tibet. Here, we recognize five valid outside-Tibet records of the snow leopard lineage. Our results suggest that the snow leopard dispersed out of the Tibetan Plateau multiple times during the Quaternary. The osteological anatomy of the modern snow leopard shows adaptation to the steep slope and, to a lesser extent, cold/high-altitude environment. Fossils and phylogeny suggest that the snow leopard experienced a gradual strengthening of such adaptation, especially since the Middle Pleistocene ( 0.8 million years). Species distribution modeling suggests that the locations of the fossil sites are not within most suitable area, and we argue that local landscape features are more influential factors than temperature and altitude alone. Our study underscores the importance of integrating morphology, fossil records, and species distribution modeling, to comprehensively understand the evolution, ecology, and inform conservation strategies for endangered species. Integrated morphology, fossil records, and SDM reveal the evolution and adaptation in the snow leopard lineage.

The structural and chemical diversity of β-glucans is reflected on the variety of essential biological roles tackled by these polysaccharides. This natural heterogeneity requires an elaborate assortment of enzymatic mechanisms to assemble, degrade or modify, as well as to extract their full biotechnological potential. Recent metagenomic efforts have provided an unprecedented growth in potential new biocatalysts, most of which remain unconfirmed or uncharacterized. Here we report the first biochemical and structural characterization of two bacterial β-glucanases from the recently created glycoside hydrolase family 157 (LaGH157 and BcGH157) and investigate their molecular basis for substrate hydrolysis. Structural analysis by X-ray crystallography revealed that GH157 enzymes belong to clan GH-A, possessing a (β/α)8-barrel fold catalytic domain, two β-sandwich accessory domains and two conserved catalytic glutamates residues, with relative positions compatible with a retaining mechanism of hydrolysis. Specificity screening and enzyme kinetics suggest that the enzymes prefer mixed-linkage glucans over β-1,3-glucans. Activity screening showed that both enzymes exhibit pH optimum at 6.5 and temperature optimum for LaGH157 and BcGH157 at 25 °C and 48 °C, respectively. Product analysis with HPAEC-PAD and LC-MS revealed that both enzymes are endo-1,3(4)-β-glucanases, capable of cleaving β-1,3 and β-1,4-linked glucoses, when preceded by a β-1,3 linkage. Moreover, BcGH157 needs a minimum of 4 subsites occupied for hydrolysis to occur, while LaGH157 only requires 3 subsites. Additionally, LaGH157 possesses exohydrolytic activity on β-1,3 and branching β-1,6 linkages. This unusual bifunctional endo-1,3(4)/exo-1,3–1,6 activity constitutes an expansion on our understanding of β-glucan deconstruction, with the potential to inspire future applications.

Stegosaurs are a small but iconic clade of ornithischian dinosaurs. They and their sister taxa, the ankylosaurs, formed the clade Eurypoda which means ‘broad-footed’. Here, we describe a stegosaur from the Upper Jurassic Qigu Formation of Xinjiang, China, based on an associated partial skeleton that includes axial, pectoral girdle, pelvic girdle, limb and armor elements. It can be diagnosed as a new taxon, Angustungui, based on numerous autapomorphies. Some morphologies of Angustungui are more similar to the taxa from Europe, Africa and North America than to those from Asia. Our phylogenetic analysis recovers it as the sister taxon of Loricatosaurus. More importantly, the narrow and claw-shaped ungual of Angustungui proves that Eurypoda, at least stegosaur, has claw-shaped unguals. Besides, we revised the character scores for Chinese stegosaurs based on observations of the specimens.Competing Interest StatementThe authors have declared no competing interest.

In this paper we consider endomorphisms of an undirected cycle graph from Semigroup Theory perspective. Our main aim is to present a process to determine sets of generators with minimal cardinality for the monoids $wEnd(C_n)$ and $End(C_n)$ of all weak endomorphisms and all endomorphisms of an undirected cycle graph $C_n$ with $n$ vertices. We also describe Green's relations and regularity of these monoids and calculate their cardinalities.

In this paper we consider the monoids of all partial endomorphisms, of all partial weak endomorphisms, of all injective partial endomorphisms, of all partial strong endomorphisms and of all partial strong weak endomorphisms of a star graph with a finite number of vertices. Our main objective is to determine their ranks. We also describe their Green's relations, calculate their cardinalities and study their regularity.

In this paper we consider three submonoids of the dihedral inverse monoid DI_n, namely its submonoids OPDI_n, MDI_n and ODI_n of all orientation-preserving, monotone and order-preserving transformations, respectively. For each of these three monoids, we compute the cardinal, give descriptions of Green's relations and determine the rank.

n/a

The jigsaw-puzzle fit of South America and Africa is an icon of plate tectonics and continental drift. Fieldwork in Angola since 2002 allows the correlation of onshore outcrops and offshore geophysical and well-core data in the context of rift, sag, salt, and post-salt drift phases of the opening of the central South Atlantic. These outcrops, ranging in age from >130 Ma to <71 Ma, record Early Cretaceous outpouring of the Etendeka-Paraná Large Igneous Province (Bero Volcanic Complex) and rifting, followed by continental carbonate and siliciclastic deposition (Tumbalunda Formation) during the sagging of the nascent central South Atlantic basin. By the Aptian, evaporation of sea water resulted in thick salt deposits (Bambata Formation), terminated by sea floor spreading. The Equatorial Atlantic Gateway began opening by the early Late Cretaceous (100 Ma) and allowed flow of currents between the North and South Atlantic, creating environmental conditions that heralded the introduction of marine reptiles. These dramatic outcrops are a unique element of geoheritage because they arguably comprise the most complete terrestrially exposed geological record of the puzzle-like icon of continental drift.