101-5 Is Mazon Creek’s “Dasyleptus” sp. a true member of the genus Dasyleptus?

Session: Paleontology, Biogeography/Biostratigraphy & Phylogenetic/Morphological Patterns

Presenting Author:

Authors:

Abstract:

A suite of fossil apterygote insect specimens of the order Archaeognatha found in the Late Pennsylvanian Mazon Creek fossil beds in northern Illinois are united under the name “Dasyleptus” sp. This taxon was originally described in 1987 by Kukalová-Peck wherein it was assigned to the genus Dasyleptus without a species name. However, this original description included a number of features inconsistent with an assignment to the genus Dasyleptus: double clawed tarsi, sclerotization, stick-like styli, leg-like cerci, and a basally thin caudal filament. Therefore, more recently, it has been termed “Dasyleptus” sp. to reflect uncertainty in the genus-level assignment. Here we carry out a thorough morphological analysis of 62 “Dasyleptus” sp. specimens to re-assess its morphology and compare to the description of the genus Dasyleptus. In all cases, we found morphological features consistent with the genus Dasyleptus, including single clawed tarsi, short abdominal styli, absent cerci, and a basally wide caudal filament. Moreover, the previously described morphological features considered inconsistent with the genus were not observed in any sample. Therefore, we conclude that the genus Dasyleptus is truly represented at the Mazon Creek fossil site.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8376

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