Mesozoic sooty mould beetles as living relicts in New Zealand

Abstract

New Zealand is an island continent that completed its split from the Gondwanan continent at 52 Ma, harbouring an iconic biota of tuatara, kiwi and weta. The sooty mould community is a distinctive trophic element of New Zealand forest ecosystems that is driven by plant-feeding sternorrhynchan Hemiptera. These produce honeydew, which supports fungal growth, which in turn supports numerous endemic invertebrates, including endemic New Zealand beetle families. Ancient New Zealand insect fossils are rare but a single fossil of a sooty mould cyclaxyrid was recently described from Cretaceous Burmese amber, a family that was previously known from two extant New Zealand species. Well-preserved fossils like this one are recasting Earth history, and, based on a wealth of additional specimens, we re-evaluate the taxonomy of Cretaceous cyclaxyrids and one Eocene species here transferred to Cyclaxyridae. Cyclaxyridae are highly tied to the sooty mould community and have now been discovered to occur in disparate biogeographic realms in deep time. Our discovery indicates that the family, and perhaps the sooty mould community in general, was widespread in Pangaea from at least the Cretaceous and survived as a relict in New Zealand. Persistence of a sooty mould ecosystem in New Zealand and fungal specialization may not necessarily be an evolutionary ‘dead-end’ for cyclaxyrids and other insects.

X-ray micro-computed tomography reveals a unique morphology in a new click-beetle (Coleoptera, Elateridae) from the Eocene Baltic amber

“…However, our finding of Baltelater gen. nov. in the North European amber challenges this hypothesis. Similar cases in which the extant southern hemisphere taxon has its closest relatives in the Baltic amber include for example cyclaxyrid 9 and some trogossitid beetles 73 , and Mantophasmatodea 74 .…”

A new genus of the subfamily Languriinae (Coleoptera: Erotylidae) from the Late Eocene Baltic amber

“…Neolitochropus hoffeinsorum Lyubarsky et Perkovsky, 2016 was transferred to Cyclaxyridae; both extant сyclaxyrid species are known only from New Zealand. This species was widespread and abundant in Eocene Europe (in total, 13 specimens of it are known from across Rovno, Bitterfeld, and Baltic amber) (Gimmel et al, 2019;Gimmel & Szawaryn, 2020), an additional species was described from Baltic amber recently (Háva, 2020). Besides, the cyclaxyrid genera Electroxyra et al, 2019 andPacyclaxyra Tihelka et al, 2021 were described from Cenomanian Burmese amber (Tihelka et al, 2021).…”

“…Extant сyclaxyrids are a part of the relict sooty mould community that is driven by scale insects from the subfamily Callipappinae (see Gavrilov-Zimin, 2018) the most ecologically important New Zealand herbivorous insects (Morales et al, 1988). These сallipappines are known to produce copious honeydew, which supports fungal growth, which in turn hold up сyclaxyrids and two other endemic beetle families (Gimmel et al, 2019). Similar relict community in the Eocene amber forests should have depended on the equable Priabonian climate with warm winters, and not accidentally the first fossil cyclaxyrid was described from Rovno and Bitterfeld amber.…”

Rhomeocalpsua torosa gen. et sp. nov., a unique lineage of Endomychidae from mid‑Cretaceous Burmese amber (Coleoptera: Coccinelloidea)

“…Mesozoic endomychids that are important for elucidating the origin and early evolution of the family are very sparse (Tomaszewska et al, 2018), while several endomychids have been formally described from Cenozoic ambers of Europe (e.g., Shockley & Alekseev, 2014;Alekseev & Tomaszewska, 2018;Reike et al, 2020; see also the list by Shockley et al, 2009a). The mid-Cretaceous Burmese amber has offered invaluable well-preserved fossils for our understanding of character evolution, phylogeny, biogeography, and palaeoecology of beetles (e.g., Cai et al, 2017aCai et al, , b, 2018Cai et al, , 2019aGimmel et al, 2019;Tihelka et al, 2021a). Burmese amber fossils also provide critical evidence of palaeodiversity of beetle families that are either currently extinct (e.g., Li et al, 2021a, b), relictual (e.g., Li et al, 2019Li et al, , 2021cTihelka et al, 2019Tihelka et al, , 2021b, or confined to the Southern Hemisphere (e.g., Li et al, 2020Li et al, , 2021d.…”