Early Middle Pleistocene sediments at Sidestrand, northeast Norfolk, yield the most extensive preglacial cold stage beetle assemblage from Britain

Abstract

Fluvial sediments (Cromer Forest-bed Formation) at Sidestrand, northeast Norfolk, have yielded the most extensive preglacial early Middle Pleistocene cold (arctic) stage beetle assemblage known from Britain. The assemblage is composed of 59 taxa indicating severely cold and continental climatic conditions. Mutual Climatic Range reconstructions suggest that the mean temperature of the warmest month (July) was between 10°C and 13°C and the mean temperature of the coldest months (January and February) between -17°C and -10°C, although the actual palaeotemperatures were probably towards the lower end of these ranges. Associated pollen and macroflora remains were poorly represented but all are known from other cold stage contexts.Excavations reveal that this freshwater arctic assemblage occurs within units between two important stratigraphic marker horizons, the Sidestrand Hall Member of the Cromer Forest-bed Formation and the first lowland glacigenic deposit (Happisburgh Till Member) in eastern England, although the ages of both remain equivocal. Recent amino-acid chronologies of molluscan faunas from the Sidestrand Hall Member indicate a MIS 13 age, with by inference, a MIS 12 age for the overlying arctic units with cold beetle fauna and for the Happisburgh Till Member. However, the arctic units are separated from the two stratigraphic marker horizons by shallow marine deposits (Wroxham Crag Formation) demonstrating at least two intervening phases of marine transgression and a cold climate marine regression. The climatic significance of these marine transgressions and their chronostratigraphic implications are currently uncertain.

The palaeontology and dating of the ‘Weybourne Crag’, an important marker horizon in the Early Pleistocene of the southern North Sea basin

“…The stratigraphy of the deposits overlying the "Weybourne Crag" at Sidestrand is complex and has been described in a number of recent papers (Preece et al, 2009;Lee, 2009;Burke et al, 2009;Lee et al, 2013;Phillips and Lee, 2013;Larkin et al, 2011Larkin et al, , 2014.…”

Aphidophagous ladybirds (Coleoptera: Coccinellidae) and climate change: a review

“…A diversity of different ladybirds that today are restricted to high latitudes or other cold climate regions are found as fossils from cooler glacial periods elsewhere, in areas that at that time would have exhibited a similar cool climate, though not today (e.g., Lemdahl, 1991; Schwert, 1992; Buckland & Buckland, 2018). In Britain and the European continent, for example, intermittent fossil records of Hippodamia arctica (Schneider) during glaciations extend back over 450 000 years to the Mid‐Pleistocene (e.g., Coope & Sands, 1966; Ponel, 1995; Coope, 2013; Larkin et al ., 2014). In contrast, the warmer interglacials and interstadials are characterised by species now characteristic of milder climates.…”

Explaining global insect species richness: lessons from a decade of macroevolutionary entomology

“…Some fossil studies continue to imply long insect species lifetimes (i.e., low extinction risk) by describing extant species from ancient deposits (Hörnschemeyer et al., ). In addition, very few Palaearctic insect species are known to have gone extinct during Pleistocene climate fluctuations (Langford et al., ; Larkin et al., ) and this seems also to be true of New Zealand beetles (Marra & Leschen, ). More geographically widespread studies of this nature are needed to tell whether such data are representative of Pleistocene extinction rates in insects.…”

“…Comparative studies of insects in this regard may yet shed light on large‐scale macroevolutionary patterns related to climate, though geographic and taxonomic biases are likely to apply just as heavily here as in more general assessments of extinction risk in insects. It will be interesting to see whether these studies can also be reconciled with the persistence of Pleistocene insects in the Palaearctic and elsewhere (Marra & Leschen, ; Langford et al., ; Larkin et al., ).…”