Lygistorrhinidae (Diptera: Bibionomorpha: Sciaroidea) in early Eocene Cambay amber.

Frauke Stebner,Hukam Singh,David A Grimaldi,Jes Rust

doi:10.7717/peerj.3313

Abstract

One new genus and three new species of Lygistorrhinidae in early Eocene Cambay amber from India are described, which significantly increases our knowledge about this group in the Eocene. Lygistorrhina indica n. sp. is the oldest fossil known from this extant genus. Indorrhina sahnii n. gen. et sp. shows morphological similarities to each of the two extant genera Lygistorrhina and Asiorrhina. Palaeognoriste orientale is the third species known from a group that has only been recorded from Eocene Baltic amber before. The latter finding reveals faunal links between Cambay amber and the probably slightly younger Baltic amber, adding further evidence that faunal exchange between Europe/Asia and India took place before the formation of Cambay amber.

Highlights

Lygistorrhinidae is a small dipteran group within the superfamily Sciaroidea of the infraorder Bibionomorpha
Findings of fossil Lygistorrhinidae in Eocene Cambay amber from India fill a gap in the spatial fossil record of the Palaeogene
Considering the scarcity of Eocene amber deposits, Cambay amber is of great significance because it fills a gap in the spatial fossil record of the Paleogene and provides information about phylogenetic relationships, divergence estimations, and biogeographic patterns of certain groups, and adds information about the palaeoenvironment

Summary

Introduction

Lygistorrhinidae is a small dipteran group within the superfamily Sciaroidea (fungus gnats) of the infraorder Bibionomorpha. The monophyly of the latter two groups has been recently confirmed with high support by molecular analysis (Ševčík et al, 2016). Members of Lygistorrhinidae can be found in tropical to temperate warm forests today (Grimaldi & Blagoderov, 2001). They can be recognized by the distinct wing venation, with a lack of the stem and sometimes the base of the fork of M veins, and generally an elongate proboscis, which is presumably for feeding from flowers (Seguyola lacks this as a derived condition) (Grimaldi & Blagoderov, 2001). It has been concluded that rareness of this group in recent collections is due a lack of sampling, which is in turn related to poor knowledge about its biology and distribution

Methods

Results

Discussion

Conclusion