Derinilipia, a new genus of Ripidiini from mid-Cretaceous amber of northern Myanmar (Coleoptera: Ripiphoridae)

Recent phylogenomic studies have confirmed that Ripi phoridae is not a monophyletic group, with Mordellidae sensu stricto nested within it (Zhang et al. 2018, McKenna et al. 2019, Cai et al. 2022).Ripiphoridae currently includes five extant subfamilies: Ptilophorinae, Pelecoto minae, Hemirhipidiinae, Ripidiinae and Ripiphorinae.Although several studies have attempted to resolve the phylogeny of Ripiphoridae using morphological or molecular data (Falin 2003, Batelka et al. 2016, Batelka & Prokop 2023), a reliable phylogenetic framework regarding the relationships of the subfamilies has not yet been established.Ripidiinae is notable among the subfamilies of Ripiphoridae, due to its larviform females (state unknown in Eorhipidiini) and reduced mouthparts (e.g.Riek 1955, Besuchet 1956, Batelka et al. 2021).The subfamily includes two tribes, Eorhipidiini and Ripidiini (Iablokoff Khnzorian 1986).Compared to the more plesiomorphic Eorhipidiini, Ripidiini possesses many specialized characters, such as eyes forming a continuous ring around head, antennae flabellate, mandibles absent, maxillary palps at most 3-segmented and sometimes fused, prothorax with contiguous coxal cavities, elytra widely separated, and abdominal sternite II visible externally.Several fossils of Ripidiini have been discovered in mid-Cretaceous Kachin amber from Myanmar.Some of them exhibit morphological features that are unknown or rarely present in their modern relatives.For example, Protoripidius Cai et al., 2018 has filiform antennae (uniflabellate in all other male Ripidiini) (Cai et al. 2018), Amberocula Batelka et al., 2018 has compound eyes di vided into upper and lower lobes (known otherwise only in Neopauroripidius Falin & Engel, 2014) (Batelka et al. 2018), and Ripidinelia Batelka & Prokop, 2019 has a spur on all tibiae (absent in all other Ripidiini) and pectinate pretarsal claws (rare in Ripidiini, though possible present in Riekella Selander, 1957) (Batelka & Prokop 2019, Li et al. 2024).In the present study, we report a new genus of Ripidiini from Kachin amber, which again shows an unusual combination of morphological characters unknown in extant ripiphorids.