Triamyxidae Qvarnström &amp; Fikáček &amp; Vikberg Wernström &amp; Huld &amp; Beutel &amp; Arriaga-Varela &amp; Ahlberg &amp; Niedźwiedzki 2021, fam. nov.
Creators: name: Qvarnström, Martin
name: Fikáček, Martin
name: Vikberg Wernström, Joel
name: Huld, Sigrid
name: Beutel, Rolf G.
name: Arriaga-Varela, Emmanuel
name: Ahlberg, Per E.
name: Niedźwiedzki, Grzegorz
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Triamyxidae

description: Family Triamyxidae fam. nov. <i>Type genus</i> <i>Triamyxa</i> gen. nov. <i>Differential diagnosis</i> Characters of the new family are put in contrast to [<b>x</b>] other myxophagan families: dorsal body surface without tubercles or ridges (<b>x</b> Lepiceridae); eyes strongly protruding (<b>x</b> Sphaeriusidae, most Hydroscaphidae); head anterior of eyes prolonged and distinctly narrowing (<b>x</b> Hydroscaphidae, Sphaeriusidae); antennal bases exposed dorsally between eyes (<b>x</b> Hydroscaphidae, Lepiceridae); antennal scapus and pedicel distinctly separated from each other (<b>x</b> Torridincolidae, Lepiceridae), exposed in dorsal view (<b>x</b> Lepiceridae, modern Hydroscaphidae); terminal maxillary palpomere long, longer than penultimate (<b>x</b> Hydroscaphidae, Sphaeriusidae); mentum large, narrowing anteriad (<b>x</b> modern Hydroscaphidae); prosternum long, with very short prosternal process (<b>x</b> Hydroscaphidae, Lepiceridae); propleuron wide, without posterior projection (<b>x</b> all modern families); mesoventrite only slightly shorter than metaventrite (<b>x</b> Hydroscaphidae, Sphaeriusidae, Torridincolidae); mesoventrite with wide subpentagonal elevation (<b>x</b> modern Hydroscaphidae, Torridincolidae); elytra only slightly shortened, exposing 1 to 2 terminal abdominal tergites (<b>x</b> all modern families), truncated posteriorly (<b>x</b> Sphaeriusidae, Torridincolidae, Lepiceridae); metanepisternum moderately wide anteriorly (<b>x</b> Sphaeriusidae, Torridincolidae, Lepiceridae); metacoxal plates present, narrow (<b>x</b> Sphaeriusidae, Torridincolidae, Lepiceridae); abdomen with 5 to 6 exposed ventrites (Figure 4; <b>x</b> Sphaeriusidae, some Torridincolidae); all abdominal segments with separate tergite and sternite (<b>x</b> Hydroscaphidae). For more details, see Table S1. From its habitus, Triamyxidae is similar to Hydroscaphidae but differs from this family in a series of characters listed above, most notably the lack of fused tergites and sternites of abdominal segments III–VI. This abdominal configuration, a very uncommon shared derived feature and synapomorphy of extant Hydroscaphidae and the Triassic <i>Leehermania</i>, is clearly absent from <i>Triamyxa</i>, where tergites and sternites of all abdominal segments are distinctly separated (FigureS1).
description: Published as part of <i>Qvarnström, Martin, Fikáček, Martin, Vikberg Wernström, Joel, Huld, Sigrid, Beutel, Rolf G., Arriaga-Varela, Emmanuel, Ahlberg, Per E. &amp; Niedźwiedzki, Grzegorz, 2021, Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin, pp. 1-8 in Current Biology 31</i> on page 3, DOI: 10.1016/j.cub.2021.05.015, http://zenodo.org/record/5061134