First fossil tumbling flower beetle-type larva from 99 million-year-old amber

Ana Zippel,Carolin Haug,Joachim T Haug,Patrick Müller

doi:10.1007/s12542-022-00608-8

Abstract

Beetle larvae often differ significantly in morphology from their adult counterparts. Therefore, it should be surprising that these immatures are often not considered to the same extent as the adult beetles. As an example, the fossil record of most beetle groups is largely represented by adult specimens. Representatives of Mordellidae, the group of tumbling flower beetles, have a cosmopolitan distribution with myriads of formally described species, based mostly on adult male specimens. Mordellidae is also well represented in the fossil record, but again only by adults; not a single fossil specimen of a larva has been reported until now. We report a new well-preserved beetle larva in 99 million-year-old Kachin amber. The larva possesses specialisations not known from the modern larvae of Mordellidae, but otherwise is clearly similar to them in many aspects. It appears possible that the fossil represents yet another holometabolan larva in Kachin amber that is associated with life within wood and/or fungi, and therefore, may have contributed to carbon cycling of the past.

Highlights

Adult tumbling flower beetles can often be encountered in the field and have, been investigated regularly; the larvae seem often omitted from research, possibly due to their often hidden way of life
We present a very well-preserved fossil beetle larva specimen preserved in Kachin amber from the Cretaceous of Myanmar
Special emphasis was lain on a particular characteristic, a process on the terminal end, present in extant larvae of Mordellidae and the fossil

Summary

Introduction

Beetles come in various forms and sizes and fulfil myriads of important ecosystem functions, both as adults, as well as in their larval forms. Mordellidae, the group of tumbling flower beetles, includes about 1500 formally described species in the modern fauna (Jackman and Lu 2002; Lawrence and Ślipinśki 2010). Tumbling flower beetles have a cosmopolitan distribution (Lawrence and Ślipinśki 2010), with highest species richness in the tropical zone, followed by relatively high numbers in subtropical and warm temperate zones (Bao et al 2019a). Adult tumbling flower beetles are often found on flowers and represent one of the most species-rich groups among beetle pollinators of flowering plants (Magnoliopsida, “angiosperms”) (Bao et al 2019b). Due to the scarceness of data on larvae, the ecology of most tumbling flower beetle larvae remains unknown as well (Liu et al 2018)

Methods

Discussion

Conclusion