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The thermostatic mechanisms of Earth’s persistent habitability remain unresolved. High-resolution Cenozoic C isotope records, P accumulation, and coarse-fraction I/Ca allow recalculation and assessment of controls on the global proportion of total carbon buried as organic carbon (f_org), a regulator of atmospheric CO₂and O₂.f_orgwas suppressed during the Eocene hothouse, coincident with an oxygenated water column and low water-column phosphate. With decreased sea level, the area for efficient organic carbon and phosphate sedimentary burial diminished, leading increasingly to greater water-column phosphate, higher primary productivity, and emergent water column deoxygenation. The sea-level influence on the areal extent of high sedimentation in shelf regions acts as a control on phosphate availability for new production, respiratory demand, and ocean oxygenation, as proposed by hypsographic models [C. J. Bjerrum, J. Bendtsen, J. J. F. Legarth,Geochem. Geophys. Geosys.7, 1–24 (2006)]. During intermediate sea-level highs of the Neogene, pulses of enhanced organic carbon burial prevailed for multimillion years, in response to the redox recycling of phosphate when oxygen minimum zones with O₂< 90 µmol/kg were present. We propose the existence of a self-limiting intermediate sea-level sweet spot with peak C_orgburial due to redox recycling of phosphate, whereby oxygen minimum zones (OMZ) with O₂< 90 µmol/kg impinge on the most C_orgrich continental shelf sediments. Such a sweet spot has narrowed over Earth history due to deepening OMZs, stabilizing both atmospheric O₂and CO₂. Continental marine inundation controls on phosphate availability, and the sedimentary carbon flux, provide a positive-feedback and rectifier to perturbations during inception of the icehouse world. 

Abstract Wild bees are widely believed to be in decline, yet most species remain unassessed for IUCN extinction risk. Geographic range size is used in risk assessments under the assumption that species with smaller ranges are more vulnerable to anthropogenic impacts. Narrow diet breadth can also increase vulnerability but is not currently incorporated into assessments.Niche breadth theory predicts a positive association between range size and diet breadth, which could concentrate risk among dietary specialists, but this relationship is not well established for bees and may differ among taxa.Here, we combined pollen‐use data from natural history collections with global occurrence records to test the relationship between diet breadth and range size across bees and among bee families. We assigned diet breadth using three metrics (categorical, numerical and phylogenetic) and estimated range size as the extent of occurrence for 633 species from six families.Across bees, range size increased with diet breadth, and diet specialists tended to occupy smaller ranges. These results suggest that range size and diet breadth jointly contribute to increased vulnerability in bees, indicating that some specialist species may merit conservation prioritisation.Our findings support the integration of trait‐based approaches for assessing extinction risk and highlight the high value of natural history data in identifying patterns of vulnerability among pollinators. 

Abstract We reconstruct the phylogeny of the most speciose genus of cuckoo bees, genus Nomada Scopoli, 1770, using 221 species from throughout its distribution, yet with a strong emphasis on the West Palearctic. For phylogenetic reconstruction, we sequenced ultraconserved elements, allowing robust phylogenetic estimates with both concatenation and coalescent-based methods. By integrating extensive information on Nomada host records, we study macroevolutionary patterns of host associations, transitions, and phylogenetic conservatism. Using Bayesian divergence time estimates, we assess the historical biogeography of the genus, focusing on the West Palearctic. Our results show that Nomada likely originated in the Eastern Mediterranean and Near Eastern region, and likely expanded its range to a near-global distribution from there. We recovered long-standing phylogenetic conservatism in the host usage of Nomada and provided strong statistical evidence for an ancestral host association with Andrena and its most recent common ancestor. However, host transitions occurred multiple times independently in the natural history of Nomada, and species of the genus are brood parasites in at least 5 genera and 4 different families of bees in the Old World. At last, we systematically revise the taxonomy of the Old World Nomada by integrating morphological study with our well-supported phylogenetic estimates. We re-establish the genus Acanthonomada Schwarz, 1966, stat. res., as a distinct, second genus in the tribe Nomadini. We recognize 13 subgenera for Nomada, 9 of which are described as new: Afronomada Straka and Bossert, subgen. nov., Colliculla Straka, subgen. nov., Gestamen Straka, subgen. nov., Hungias Straka, subgen. nov., Mininomada Straka, subgen. nov., Nomacolla Straka, subgen. nov., Nomonosa Straka, subgen. nov., Plumada Straka, subgen. nov., and Profuga Straka, subgen. nov. Aside from the subgenus Nomada s.s., we reinstitute 3 previously synonymized subgenera: Heminomada Cockerell, 1902, stat. res., Holonomada Robertson, 1903, stat. res., and Hypochrotaenia Holmberg, 1886 stat. res. A total of 15 subgeneric names are formally synonymized with the newly established subgeneric concepts. 

Establishing a higher classification of bees based on morphology alone can fail to capture evolutionary relationships when morphological characters either vary very little between distantly related groups, or conversely vary greatly between closely related species. This problem is well represented in the subfamily Panurginae, for which a recent global revision based on phylogenomic data unexpectedly revealed that two Old World species previously placed in Camptopoeum Spinola and Flavipanurgus Warncke, are in fact most closely related to each other, and together form a sister group relationship to the remaining Flavipanurgus and Panurgus Panzer combined. To rectify this situation, we here establish an expanded phylogenomic data set of Old World Panurgini and re-assess generic and subgeneric concepts for the tribe. To solve the paraphyly of Camptopoeum and Flavipanurgus , we establish the new genus Halopanurgus gen. nov. containing the species H. baldocki (Wood & Cross), comb. nov. and H. fuzetus (Patiny), comb. nov. , both of which are restricted to coastal sands, saltmarshes, and inland saline lagoons in the extreme south of Portugal and south-west of Spain. Re-evaluation of four recently used subgenera in Panurgus strongly supports a simplified classification of two subgenera; Pachycephalopanurgus Patiny, stat. rev. including Micropanurgus Patiny syn. nov. , and Panurgus s. str. including Euryvalvus Patiny. Pachycephalopanurgus species seem to be oligoleges of Asteroideae (Asteraceae), whereas Panurgus s. str. may be oligoleges of Cichorieae (Asteraceae). Our findings reinforce the challenges of establishing a phylogenetically sound classification of Panurginae using morphology alone and illustrate that even in well-studied regions like Europe unrecognised genera can persist in underexplored corners of the continent.