DOI: 10.3897/asp.81.e101374

Authors: Kateřina Rosová, Jakub Prokop, Jörg U. Hammel, Rolf G. Beutel

Abstract: Omophroninae is a distinctive monogeneric group of Carabidae, presumably placed relatively close to the root of the megadiverse adephagan family. In the present study we describe a larva belonging to Omophroninae from mid-Cretaceous Burmese amber and erect a new genus †Cretomophron. Several features support the placement in this small but distinctive subfamily, such as the wedge-shaped head, the large triangular nasale, the elevated antennae with the apical segment directed sideways, the large and bidentate mandibular retinaculum, the enlarged hexagonal prothorax, legs with a distinct armature of spines, and the relatively narrow and posteriorly tapering abdomen. In contrast to larvae of the extant genus Omophron Latreille, the posterior tentorial grooves are not shifted backwards, apparently a plesiomorphic feature, the 2nd antennomeres are markedly longer, and the legs bear long setae and rather thin and long spike-like setae. †Cretomophron also differs in the presence of numerous setae arranged in transverse rows on abdominal segment VI. Lateral lobe-like expansions of abdominal tergites are a conspicuous feature of the new genus but similar structures occur in later instars of Omophron. Structural specializations of the head, prothorax and legs strongly suggest that the larvae were burrowing in sand, like adults and larvae of the extant genus, and that they were efficient predators, detecting prey with the unusually shaped antennae and long maxillae, grasping it with the elongate apical mandibular tooth, and squeezing and piercing it between the bidentate retinaculum and large and triangular nasale.

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DOI: 10.3897/asp.80.e84114

Authors: Jan Erik Sedlmeier, Arnaud Faille

Abstract: The past climatic changes caused repeated distribution shifts within insect populations leading to a highly diverse fauna in the mountain regions, which have acted as a refuge for many groups. There, some taxa have adapted to high altitudes and cold climatic conditions. One of those is the highly diverse and Holarctic subgenus Cryobius Chaudoir, 1838 (Carabidae: Pterostichus) including both locally and widely distributed species. Isolated and morphologically divergent populations of the same species led to the description of many subspecies. Until now, there has been no comprehensive work concerning the phylogeny of Cryobius, and genetic data on this taxon are sparse. This study is the first to provide insights into the molecular phylogeny of this subgenus, focusing on species from the Pyrenean and Cantabrian mountain systems. Cryobius specimens were sequenced targeting mitochondrial and nuclear genes. A molecular phylogeny was then built, merging the new data with genetic data from online public databases. All species of Cryobius included in this study form a monophyletic clade within Pterostichus. The synonymy of the two former taxa Pyreneorites and Haptoderus with Cryobius is confirmed by this study. Cryobius of the Pyreneo-Cantabrian area are closely related. Moreover, several well-supported clades of local species were found. The results further indicate a relation between Nearctic and Eastern Palearctic Cryobius, in agreement with the theory of faunal and floral colonization of North America via the Bering land bridge.

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