Anaxyelidae of Karatau: 100 Years After †
1
Institute of Zoology, 93 Al-Farabi Avenue, Almaty 050060, Kazakhstan
2
Paleontological Institute, Russian Academy of Sciences, 123 Profsoyuznaya Street, Moscow 117647, Russia
3
Natural History Museum, London SW7 5BD, UK
*
Author to whom correspondence should be addressed.
†
urn:lsid:zoobank.org:pub:D9BBA3C6-369B-49AD-B76F-F0A1C8681753.
Insects 2025, 16(9), 943; https://doi.org/10.3390/insects16090943
Submission received: 2 August 2025
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Revised: 1 September 2025
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Accepted: 2 September 2025
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Published: 9 September 2025
(This article belongs to the Special Issue Fossil Insects: Diversity and Evolutionary History)
Simple Summary
The family Anaxyelidae is a relict group of woodwasps, represented in the extant fauna by a single surviving species. In stark contrast to its dwindling present-day diversity, Anaxyelidae was among the most prosperous and diverse hymenopteran groups in the Late Mesozoic. Taxonomically, the family is divided into two subfamilies: Anaxyelinae, dominant in the Jurassic, and Syntexinae, which prevailed in the Cretaceous and survive to the present. Until now, only one Jurassic record of Syntexinae was known—from the Middle Jurassic of China. During our 2025 fieldwork, we discovered the second Jurassic representative of Syntexinae in the Late Jurassic deposits of Karatau (Kazakhstan). The fossil sites of the “Jurassic Lake of Karatau” complex have seen very limited excavation over the past 50 years. During our expedition, we visited all the key sections of Karatau. These outcrops are in satisfactory condition and merit further exploration.
Abstract
The fossil beds of the Karabastau Formation in southern Kazakhstan, known as the “Jurassic Lake of Karatau”, represent one of the richest Lagerstätten for Jurassic insects, with more than 800 described species. This year marks the centenary of the first fossil insect descriptions from Karatau, published by A.V. Martynov in 1925. Among the most prominent insect groups from this locality are the Anaxyelidae, a relict family of siricoid woodwasps. Here we report the first occurrence of the subfamily Syntexinae in Karatau, based on a newly discovered and described genus and species, Karasyntexis martynovi gen. et sp. nov., from the Galkino locality. This is only the second Jurassic record of Syntexinae globally. We provide a detailed morphological description of the new taxon and compare it with related syntexine genera. In addition, we reassess the current state of the four historically known fossiliferous localities of the Karabastau Formation (Galkino, Mikhailovka, Karabastau, and Chugurchak), all of which were revisited during a 2025 field expedition. A total of 22 anaxyelid species are now known from Karatau, highlighting the site’s exceptional paleodiversity. Our findings suggest that the true diversity of Karatau’s anaxyelids remains significantly underexplored and underscore the importance of renewed paleontological research in this classic locality.
Keywords:
Hymenoptera; Syntexinae; woodwasp; wasp; insect; Kazakhstan; Karabastau; Galkino; Mikhailovka; Jurassic; fossil; new taxa
