Nest Volume and Distance between Nests Do Not Affect Population Size or Species Richness of the Termitophilous Corotocini Fauna

Revalidation of the termitophilous genus Ceratoxenus Mann and description of two new species from the Neotropical region (Coleoptera: Staphylinidae: Aleocharinae: Corotocini)

Termitogastrina is a subtribe of termitophilous rove beetles distributed mostly across Neotropical and Afrotropical regions. In 1923, William M. Mann established the genera Ceratoxenus and Xenopelta from material collected by Alfred E. Emerson in Guyana. Nine years later, Emerson himself synonymized the genera, in what seems to be a result from the misidentification of specimens. In this work, we revalidate the genus Ceratoxenus, provide its redescription and a taxonomical key for the species, along with a comparative diagnosis with the genus Xenopelta. Additionally, two new species of Ceratoxenus are described: C. akerata sp. nov. and C. inflatus sp. nov., respectively, from Panama and Guyana. This paper also marks a new record for the genus Ceratoxenus for Panama.

A New Termitophilous Rove Beetle from Brazil Suggests an Undersampling Scenario and Cospeciation between Termites and their Termitophiles in the Neotropical region (Coleoptera: Staphylinidae: Aleocharinae)

Numerous staphylinid species can be found in termite nests. While the distributional range of termite hosts has been well studied, the same cannot be said for their associated fauna. There is a lack of comprehensive sampling even in areas where termite fauna has been well-sampled. In recent surveys in Southeastern Brazil, we collected a new species of termitophilous rove beetle from the tribe Termitohospitini (Aleocharinae): Termitosocius boraceiensis sp. nov., is herein described. The new species is the first termitophile found in Boracéia, SP, Brazil, even with decades of termite sampling in the place. Additionally, we discuss the diversity and description rate of neotropical Termitohospitini, and investigate the potential of cospeciation between termites and their termitophilous beetles on the Emerson-Kistner principle. Our findings suggest that the neotropical Termitohospitini may be more diverse than previously believed and that Termitosocius species are present in host species that are geographically separated, implying a cospeciation scenario. Additional sampling is required to fully comprehend the relationships between termitophiles and their termite hosts. The outcomes of this study provide new insights into the undersampling scenario and possibly cospeciation between termites and their termitophiles in the Neotropical region.

The Earliest Corotocini (Insecta: Coleoptera: Staphylinidae) from Dominican Amber, with Remarks on Post-Imaginal Growth Influence on Termitophile Taxonomy

Simple Summary

The tribe Corotocini is one of the most diverse and morphologically specialized groups of rove beetles associated with termites. All species of Corotocini present some degree of membranous enlargement of the abdomen, called physogastry. The development of physogastry occurs after the beetle emerges from the pupa as an ordinary beetle and is accompanied by further modifications related to its sclerotized parts, which makes the early stages (stenogastrics) strikingly different from the fully developed forms (physogastrics). The present study reports the very first fossil record for Corotocini, with a new genus and species, Pareburniola dominicana gen. et. sp. nov., from Miocene Dominican Republic amber. The fossil is represented by a stenogastric individual, which poses challenges in the taxa description since the last stage of development remains unknown. We utilize the current knowledge of post-imaginal growth in Corotocini to understand what is likely and not likely to change in the morphology during this phenomenon.

Abstract

Pareburniola dominicana Zilberman, Yin & Cai gen. et. sp. nov. is the very first fossil record of the tribe Corotocini, reported from Miocene Dominican Republic amber. The new species, which is based on a stenogastric individual, is described and illustrated and is included in the subtribe Corotocina due to the combination of a tarsal formula 4-4-4, an elongated gula, a developed labial palp, a reduced fourth palpomere, separated metacoxae and a glandular structure on the posterior region of the head. Since the taxon belongs to the physogastric tribe Corotocini, which presents post-imaginal growth, this phenomenon is herein discussed, and its current knowledge is used to understand the possible outcomes during morphological changes in the fossil species.