An unusual 100-million-year old holometabolan larva with a piercing mouth cone

Abstract

Holometabola is a hyperdiverse group characterised by a strong morphological differentiation between early post-embryonic stages (= larvae) and adults. Adult forms of Holometabola, such as wasps, bees, beetles, butterflies, mosquitoes or flies, are strongly differentiated concerning their mouth parts. The larvae most often seem to retain rather plesiomorphic-appearing cutting-grinding mouth parts. Here we report a new unusual larva preserved in Burmese amber. Its mouth parts appear beak-like, forming a distinct piercing mouth cone. Such a morphology is extremely rare among larval forms, restricted to those of some beetles and lacewings. The mouth parts of the new fossil are forward oriented (prognathous). Additionally, the larva has distinct subdivisions of tergites and sternites into several sclerites. Also, the abdomen segments bear prominent protrusions. We discuss this unusual combination of characters in comparison to the many different types of holometabolan larvae. The here reported larva is a new addition to the ‘unusual zoo’ of the Cretaceous fauna including numerous, very unusual appearing forms that have gone extinct at the Cretaceous–Palaeogene boundary.

Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding “Fossils from conflict zones and reproducibility of fossil-based scientific data”: Myanmar amber

“…c Restoration drawing in dorsal view. d Extremely unusual holometabolan larva in dorsal view; the character combination is so unusual that we cannot even tell whether this specimen represents a lacewing or a beetle or something closely related to both (Haug et al 2020b, re-figured under CC BY 4.0); the specimen of Kachin amber was legally acquired and originally part of the collection of Patrick Müller; it was later donated to the Staatliche Naturwissenschaftliche Sammlungen Bayerns-Bayerische Staatssammlung für Paläontologie und Geologie in Munich (SNSB-BSPG 2019 I 171)…”

A Bizarre Planthopper Nymph (Hemiptera: Fulgoroidea) from Mid-Cretaceous Kachin Amber

“…The most striking morphological feature of the fossil is its body covered by numerous spines and tubercles (i.e., armour). Such structure is common among some insect larvae from mid-Cretaceous Kachin amber [ 29 , 30 , 31 , 32 ], but very rare in extant and extinct planthoppers. By the Early Cretaceous, many new predaceous arthropods (including some spiders, lacewing larvae, and ants) and vertebrates (including lizards, birds, and mammals) had appeared [ 33 , 34 , 35 ], so S. shcherbakovi probably used these spines and tubercles to protect itself from predators.…”

Diversity of culicomorphan dipterans in the Eocene Kishenehn Konservat-Lagerstätte (Montana, USA) and its palaeoecological implications

“…Wherever possible, we decided not to use Linnean ranks ('rankless taxonomy'). Ranks (or "categories" sensu Mayr, 1942, p.102) represent arbitrary constructs in a way that do not hold 'comparative values' (Mayr, 1942, p. 291, line 3) and, in our view, do not contribute to an easier understanding of the phylogenetic relations among species and higher groups (Haug et al, 2020).…”