The first whirligig beetle larva from mid-Cretaceous Burmese amber (Coleoptera: Adephaga: Gyrinidae)

Burmese amber reveals a new stem lineage of whirligig beetle (Coleoptera: Gyrinidae) based on the larval stage

“…Most larval members of the Dineutini have denticles on the inner margin of the mandible (Archangelsky & Michat, 2007;Michat et al, , 2017bMichat & Gustafson, 2016). Zhao et al, (2019). E, Gyrinus vicinus Aubé, 1838.…”

“…Another gyrinid larva, Cretogyrus beuteli, was recently described from Burmese amber (Zhao et al, 2019). This taxon was not placed at the tribal level despite clearly exhibiting features suggesting placement in crown Dineutini.…”

“…1D to 2). However, the original description lacks further key information with regard to the lacinia (Zhao et al, 2019). Xiangdong Zhao kindly provided us with high-resolution images of the cephalic capsule in order to allow us to study the gross morphology of the maxilla (Fig.…”

“…6; Supporting Information, Figs S1-S4) with support for the currently recognized tribes and their relationships within the Gyrininae . Although all analyses place Cretogyrus as nested in Dineutus, this is likely a result of the large amount of missing data for Cretogyrus owing to the lack of chaetotaxic analysis in the original description (Zhao et al, 2019), because this taxon was coded, in part, from the literature and from additional high-resolution images of the head provided by X. Zhao, but this did not allow the study of maxillary chaetotaxy. All phylogenetic analyses strongly support our amber specimen as being sister to both Dineutini and Orectochilini [BI without Cretogyrus (Fig.…”

“…Among fossil Gyrinidae, specimens are known from Baltic amber (Hatch, 1927). Most recently, a larva, Cretogyrus beuteli Zhao et al, 2019, was described from Burmese amber (Zhao et al, 2019). The larvae of several extant gyrinid genera remain unknown, including key taxa, such as Spanglerogyrus Folkerts, 1979 andHeterogyrus Legros, 1953, representing the subfamilies Spanglerogyrinae and Heterogyrinae (Miller & Bergsten, 2012), and for some genera in the subfamily Gyrininae, such as the dineutine genus Porrorhynchus Laporte, 1835 and the gyrinine genus Metagyrinus Brinck, 1955 (Michat et al, 2017b).…”