Baltoparalethus alessioboninoi sp. nov.Figs 1, 2Etymology. —The species is named after Alessio Bonino, the son of the senior author of this study.Locality and horizon. —Baltic Sea coast, Yantarny settlement (formerly Palmnicken), Sambia (Samland) Peninsula, Kaliningrad Region, Russia.Material. —Holotype, male. Currently in the collection of the Back to the Past Museum, Cancún, Mexico, coll. no. BPM 1134. To be transferred to a paleontological museum facility in Miami, USA within the next two years. It is possible that the holotype represents a nymph, but given the currently limited knowledge of the genital morphology of fossil Eumastacoidea at different developmental stages, this is uncertain. There are also no wing pads visible, which would help determine the stage of the specimen.Diagnosis. —As for genus (monotypical).Description. —As for genus (monotypical). See comment made above for the “ diagnosis / description ” of the genus.Measurements [mm]. —Body length (front of head to tip of cercus) 8.0. Head height 2.7. Height of compound eye 1.1, width 0.68. Antenna length (including scape and pedicel) ca. 1.9. Length of maxillary palpus ca. 0.41. Pronotum length (along dorsal line in lateral view) 1.3; height (maximum height in lateral view) 0.64. Thoracic height below pronotum 1.45. Mesotibia 1.56 long. Mesotarsus 1.23 long (0.4 / 0.12 / 0.71 for 1 / 2 / 3 segment; length of third segment including pulvillus). Metafemur 4.6 long, 0.65 wide (maximum width). Metatibia 2.85 long. Metatarsus 1.85 long (1.0 / 0.28 / 0.57). Cercus 0.68 long. Supra-anal plate 0.45 long.