In search for the unlikely: Leaf-mining caterpillars (Gracillariidae, Lepidoptera) from Upper Cretaceous and Eocene ambers Author Fischer, Thilo C. https://orcid.org/0000-0001-7371-4053 Bavarian State Collection of Zoology, Muenchhausenstrasse 21, 81247 Muenchen, Germany thilo.fischer@4gene.de text Zitteliana 2021 2021-12-08 95 135 145 http://dx.doi.org/10.3897/zitteliana.95.63317 journal article http://dx.doi.org/10.3897/zitteliana.95.63317 2747-8106-95-135 F0DEFCBA9EAF43EE93C2AD1D6E88BD5B 18933B34F8305449A0B21C682D7D39B7 Phyllonorycter inopinata nov. spec. Etymology. The species name '' Phyllonorycter inopinata " "surprising" refers to the seemingly unlikely find of a leaf mining caterpillar preserved in amber. Holotypus. Specimen ex coll. Fischer no. 8182, Fig. 1 Locus typicus. Amber mine of Yantarni, RUS Stratum typicum. "Blaue Erde" (Upper Eocene to Lower Oligocene) Repository. Bavarian State Collection of Zoology, Munich, Germany; accession number SNSB-ZSM-LEP amb003. Description of holotype. The caterpillar is 5 mm long and subcylindrical, maximum width 0.73 mm (in A4). The head is 0.36 mm long and 0.5 mm broad, depressed, triangular, and prognathous. Mandibles and antennae are developed. The legs are small (0,15-0.2 mm long). The thorax (T1 to T3) is 0.45 mm long and 0.63 mm broad. The longest abdominal segment is 0.61 mm (A4), the shortest abdominal segment is 0.3 mm (A9). Prolegs at abdominal segments A3 to A5 are small. There are three setae in lateral positions on either side of each segment, these are maximal 0.2 mm in length and could not be exactly positioned. The terminal segment is 0.21 mm long and 0.43 mm broad. Diagnosis. A differential diagnosis to other Phyllonorycter species is currently impossible. The holotype is the only known specimen of the new species P. inopinata . Consequently, there is no information on variability and differences between subsequent instars. A comparison to similar extant species like P. leucographella or P. platani suffers from the same insecurities. Future findings from Baltic amber may enable a differential diagnosis.