Coxoplectoptera, a new fossil order of Palaeoptera (Arthropoda: Insecta), with comments on the phylogeny of the stem group of mayflies (Ephemeroptera)

Müller²,

2019

Zoological Lett

Background Biological diversity is a hot topic in current research, especially its observed decrease in modern times. Investigations of past ecosystems offer additional insights to help better understand the processes underlying biodiversity. The Cretaceous period is of special interest in this context, especially with respect to arthropods. During that period, representatives of many modern lineages appeared for the first time, while representatives of more ancient groups also co-occurred. At the same time, side branches of radiating groups with ‘experimental morphologies’ emerged that seemed to go extinct shortly afterwards. However, larval forms, with their morphological diversity, are largely neglected in such studies, but may provide important insights into morphological and ecological diversity and its changes in the past. Results We present here a new fossil insectan larva, a larval lacewing, in Cretaceous amber, exhibiting a rather unusual, ‘experimental’ morphology. The specimen possesses extremely large (in relation to body size) mandibulo-maxillary piercing stylets. Additionally, the labial palps are very long and are subdivided into numerous elements, overall appearing antenniform. In other aspects, the larva resembles many other neuropteran-type larvae. Conclusions We provide a comparison that includes quantitative aspects of different types of neuropteran larvae to emphasise the exceptionality of the new larva, and discuss its possible relationships to known lineages of Neuroptera; possible interpretations are closer relationships to Dilaridae or Osmylidae. In any case, several of the observed characters must have evolved convergently. With this new find, we expand the known morphological diversity of neuropterans in the Cretaceous fauna.

Section: Introductionmentioning

confidence: 99%

“…252 mya), but being extinct in later faunas. This includes, for example, very early offshoots of the evolutionary lineage of mayflies [10] and cockroaches [11].…”

Section: Introductionmentioning

confidence: 99%

A 100-million-year old predator: a fossil neuropteran larva with unusually elongated mouthparts

Müller²,

2019

Zoological Lett

“…The Cretaceous fauna seems to be especially diverse due to three factors : (1) The survival of 'old' morphologies known from the Palaeozoic, but extinct after the Cretaceous, as exemplified by certain mayflies (Godunko, Staniczek & Bechly, 2011) or cockroach-like dictyopterans (Hörnig et al, 2018). (2) The emergence and diversification of new and distinctive morphological and functional types, such as ants and bees (Dlussky, 1996;Anderson, 2009).…”

Section: Diversity Of the Cretaceous Faunamentioning

confidence: 99%

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

Schädel

Baranov

et al. 2020

PeerJ

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.

“…provide a taxonomic or phylogenetic signal as well.Fossil larvae may possess more plesiomorphic characters no longer represented in the modern fauna, providing important clues for reconstructing character evolution (Müller & Walossek, 1986a, 1986b; Walossek & Müller, 1990; Wang, Ponomarenko & Zhang, 2009; Godunko, Staniczek & Bechly, 2011; Haug & Haug, 2013, 2015, 2016; Haug et al, 2013a, 2015; Badano et al, 2018). Fossil larvae of such more ancestral forms (under point 5) may persist longer in time than at first expected (‘morpho-type survival’ in the sense of Haug et al, 2012) extending the range of such larval morphologies (Kukalova-Peck, 1978; Godunko, Staniczek & Bechly, 2011; Haug, Haug & Garwood, 2016). Fossil larvae may possess characters today only known from different modern lineages, but not occurring together in the same specimen, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Fossil larvae may possess more plesiomorphic characters no longer represented in the modern fauna, providing important clues for reconstructing character evolution (Müller & Walossek, 1986a, 1986b; Walossek & Müller, 1990; Wang, Ponomarenko & Zhang, 2009; Godunko, Staniczek & Bechly, 2011; Haug & Haug, 2013, 2015, 2016; Haug et al, 2013a, 2015; Badano et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Beetle larvae with unusually large terminal ends and a fossil that beats them all (Scraptiidae, Coleoptera)

2019

PeerJ

Larvae, and especially fossil larvae, are challenging to deal with from a purely taxonomic view. Often one cannot determine which species the larvae belong to. Yet, larvae can still contribute to various scientific questions. Especially morphological traits of a fossil larva can be highly informative for reconstructing character evolution. Also the occurrence of specific larval types and larval characters in time and the disappearance of such forms can well be reconstructed also without being able to narrow down the phylogenetic relationship of a larva very far. Here, we report two new beetle larvae preserved in Baltic amber which are identified as representatives of Scraptiidae, based on an enlarged terminal end (‘9th abdomen segment’); this is only the third record of such larvae. In comparison to modern forms, the terminal ends of the two new fossil larvae is even larger in relation to the remaining body than in any known larva. Unfortunately, our knowledge of such larvae in the modern fauna is very limited. Still, one of the two already known fossil larvae of Scraptiidae also has a very long terminal end, but not as long as those of the two new fossils. These three fossil larvae therefore seem to possess a specific morphology not known from the modern fauna. This might either mean that they (1) represent a now extinct larval morphology, a phenomenon well known in other euarthropodan lineages, or that (2) these forms represent a part of the larval phase not known from modern day species as they have not been described yet; such cases occur in closely related lineages. In any case, the fossils expand the known diversity of larval morphologies.