Merithone laetitiae sp. nov. Montagna & Magoga Code Zoobank: LSID urn:lsid:zoobank.org:act: 968E793A-F8F8-4B60-ADFE-E0B724A7F1EA Etimology: laetitiae is derived from the prosoponym Laetitia, the daughter of the first author, to whom the species is dedicated. Material: holotype specimen MCSN 8679, Museo Cantonale di Storia Naturale, Lugano, Switzerland. Type horizon: upper Kalkschieferzone member of Meride Limestone Formation. Type locality: VM12 site (45° 53 ′ 26 ʺ N, 8° 56 ′ 49 ʺ E), Val Mara valley near Meride (Monte San Giorgio, Switzerland). Diagnosis: as for the genus, being the only species. Description (Figs. 3, 4, 5). Almost complete specimen of ~ 6.4 mm length, preserved in dorso-lateral view. Prognathous head (0.6 mm in length) with prominent compound eyes of 0.4 mm diameter; eyes surrounded by short spines; chewing mouthpart with visible mandibles and the short maxillary palps (only the left visible); filiform antennae composed of more than 20 antennomers (2.04 mm in length) (Fig. 4). Well-developed prothorax (0.6 mm) but shorter than meso- plus metathorax; sub-rectangular, partially crushed mesothorax (length = 0.8 mm, maximum width = 0.95 mm) covered with long setae especially visible on the anterior ridge (Fig. 4). Metathorax of 0.5 mm in length and 0.67 mm of width, respectively. Forelegs visible, one almost complete (coxa, trochanter, femur of 0.8 mm, tibiae of 0.91 mm, and tarsus of 0.97 mm; Fig. 4), while only tibiae and tarsus of the other are visible. Abdomen of 1.3 mm in length partially visible. Wings (Figs. 3, 5). Two pairs of subequal membranous wings without pterostigma and with many veins, long setae present on veins, except for the costal (C) vein, where setae are shorter and denser. Forewings elongate, ~ 2.7 times as long as wide (length: 5.1 mm; maximum width of inter radial area: 1.92 mm), with a distally rounded shape; moderately broad costal area (until its mid; maximum width 0.29 mm), then gently decreasing distally until the joining with subcostal (SC) vein, and proximally at the wing base. Costal area with numerous veinlets that, in the proximal part of the wing, are bifurcated. SC vein almost straight, terminating distally on R; few cross veins between R and RS, the latter with six primary branches. Medial (M) veins not coalesced with RS basally, the former is separated in medial anterior (MA) and medial posterior (MP). Cubital anterior 1 distally forked, cubital posterior simple. Anal veins not clearly visible. Hind wings are visible and subequal to forewings (Fig. 3), as demonstrated by the right hind wing almost completely overlapping the corresponding forewing, the left hind wing is crumpled, and venations are only partially visible.

Published as part of Montagna, Matteo, Magoga, Giulia & Magnani, Fabio, 2024, The Middle Triassic palaeontomofauna of Monte San Giorgio with the description of Merithone laetitiae († Permithonidae) gen. et sp. nov., pp. 1-10 in Swiss Journal of Palaeontology (17) (17) 143 (1) on pages 6-8, DOI: 10.1186/s13358-024-00317-6, http://zenodo.org/record/12005564