Notes on rhopalosomatid wasps of Dominican and Mexican amber (Hymenoptera: Rhopalosomatidae) with a description of the first fossil species of &amp;lt;i&amp;gt;Rhopalosoma&amp;lt;/i&amp;gt; Cresson, 1865

Volker Lohrmann,James P Pitts,Michael Ohl,Laurent Jeanneau,Peter Michalik,Vincent Perrichot

doi:10.5194/fr-22-31-2019

Abstract

Abstract. Rhopalosomatidae are a family of aculeate wasps that are ectoparasitoids of crickets as larvae and are predominantly distributed pantropically. The published fossil record of the family is scarce. Here, we report three new fossil rhopalosomatid wasp specimens from Dominican and Mexican amber. Rhopalosoma hispaniola Lohrmann sp. nov. is described and documented from Dominican amber by two separate inclusions – one of each sex. An additional fossil female Rhopalosoma is described and documented from Mexican amber but is not named due to the insufficient preservation of the fossil. The new fossils, which are morphologically intermediate between Townes' isopus and poeyi species groups, do not only represent the first fossil records of an extant genus of this peculiar family but also the first records of the family in Dominican and Mexican amber.

Highlights

The Recent New World fauna of Rhopalosomatidae is currently comprised of 35 formally described species assigned to three genera: Liosphex Townes, 1977, with 13 species, Olixon Cameron, 1887, with 5 species, and Rhopalosoma Cresson, 1865, with 17 species (Townes, 1977; Lohrmann and Ohl, 2010; Lohrmann et al, 2012)
The aim of the present study is to describe and illustrate these fossils, which are the first fossil records of the genus but are the first of the family from Dominican and Mexican amber and from the Miocene as a whole
Based on the presence of a median tooth on the tarsal claws, females of Rhopalosoma are identified, and there is no doubt about the generic placement of the new species described

Summary

Introduction

The Recent New World fauna of Rhopalosomatidae is currently comprised of 35 formally described species assigned to three genera: Liosphex Townes, 1977, with 13 species, Olixon Cameron, 1887, with 5 species, and Rhopalosoma Cresson, 1865, with 17 species (Townes, 1977; Lohrmann and Ohl, 2010; Lohrmann et al, 2012) Their distribution ranges from southeastern Canada and the northeastern USA to northern Argentina and southern Brazil, with the vast majority occurring in the tropic zone. The recent discovery of an ectoparasitoid rhopalosomatid wasp larva attached to its cricket host in mid-Cretaceous Burmese amber revealed a remarkable constancy of the biology of Rhopalosomatidae over the last 100 million years (Lohrmann and Engel, 2017) In some way, this extraordinary fossil hides the fact that we still know little about the origin and evolution of this peculiar family of aculeate wasps. This leaves Eorhopalosoma Engel, 2008, which is another Cretaceous Burmese amber fossil, as the sole fossil species in the family so far

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