List of characters used in cladistics analysis (matrix provided as electronic appendage)

The data are largely based on Yan et al. (2017). One character (prosternal grooves for protarsi) was removed as it is only informative within Cupedidae. Characters 18 and 19 were added. The taxon sampling was slightly modified. Two ademosynid genera were added and few terminals from the extant suborders were removed of replaced.

  1. Externally visible membranes: (0) present; (1) absent. Largely or completely absent in fossil beetles and also in extant groups with very few exceptions (e.g., Ponomarenko, 1969; Beutel et al., 2008).
  2. Tubercles: (0) absent or indistinct; (1) present. Distinct in Cupedidae and Ommatidae, and also in stem group Coleoptera (Beutel et al., 2008). Absent in †Ademosynidae, †Catiniidae, †Peltosynidae, †Schizophoridae (partim; Ponomarenko, 1969) and in extant groups.
  3. Scale-like setae: (0) absent; (1) present. Absent in all species of †Ademosynidae, in other extinct groups lacking cuticular tubercles, in extant Archostemata excl. Cupedidae and Ommatidae, and in extant non-archostematan beetles.
  4. Punctuation of body surface: (0) punctures absent or with lower density; (1) dense punctuation. Very dense punctuation present in †Ademosynidae, Archosyne and †Peltosynidae. Unusually coarse in Peltosyne (Yan et al., 2017).
  5. Ocelli: (0) three; (1) absent. Absent in †Ademosynidae and †Peltosynidae, and also missing in almost all other extant and extinct groups.
  6. Shape of head capsule: (0) not distinctly transverse; (1) distinctly transverse. Distinctly transverse head in †Peltosynidae and few extant groups.
  7. Constricted neck and postocular extensions: (0) absent or indistinct; (1) present. Absent in †Ademosynidae and most other extant and extinct groups. Usually present in Archostemata (e.g., Beutel et al., 2008)
  8. Supraantennal protuberance (P1): (0) absent; (1) present. Present as moderately distinct bulge above antennal base in Ommatidae and as distinct protuberance in extant Cupedidae (Beutel et al., 2008; Hörnschemeyer, 2009).
  9. Supraocular protuberance (P2): (0) absent; (1) present as moderately distinct bulge; (2) present as strongly pronounced protuberance. Distinct protuberance in most extant Cupedidae (Beutel et al., 2008), moderately distinct supraocular bulge in some other archostematan groups (e.g., Pace, 1975) and in Archosyne and Sylvacoleus (Ponomarenko, 1969).
  10. Posteromesal protuberance (P3): (0) absent; (1) present, moderately convex; (2) conspicuous, strongly convex. Present in Cupedidae and Tetraphalerus and Sikhotealinia (Beutel et al., 2008). Absent in fossil taxa under consideration (Ponomarenko, 1969).
  11. Posterolateral protuberance (P4): (0) absent; (1) present. Present on posterolateral head region in some genera of Cupedidae (Beutel et al., 2008).
  12. Cephalic antennal groove; (0) absent; (1) below compound eye; (2) above compound eye. Present below compound eyes in Tetraphalerus and Peltosyne (Yan et al., 2017), and above it in Crowsoniella (Pace, 1975) and Jurodidae (Kirejtshuk, 1999). Absent in Omma, Cupedidae and Micromalthus, and also missing in coleopteran stem group taxa with the possible exception of †Rhombocoleidae (Ponomarenko, 1969).
  13. Number of antennomeres: (0) 13 or more; (1) 11 or less. Thirteen in †Tshercardocoleidae, †Permocupedidae and †Rhombocoleidae), but eleven in other fossil taxa with preserved antennae (Ponomarenko, 1969; Beutel et al., 2008). Eleven or less in extant beetles.
  14. Location of antennal insertion on head capsule: (0) laterally; (1) dorsally. Laterally in †Ademosynidae like in most other most extant beetles and fossils beetles (Ponomarenko, 1969; Beutel et al., 2008). On dorsal side in Cupedidae excl. Priacma (Beutel et al., 2008) and in Sikhotealinia (Kirejtshuk, 1999).
  15. Mandibular mola: (0) absent; (1) present. Present in Myxophaga and many basal polyphagan groups (e.g., Lawrence et al., 2011). Also present in †Peltosynidae (Yan et al., 2017). Absent in Archostemata and Adephaga (Beutel et al., 2008). Not verifiable in most fossils including ademosynid genera.
  16. Cutting edge of mandible: (0) horizontal, (1) three vertically arranged teeth. Three vertically arranged teeth in Ommatidae and Micromalthus (e.g., Beutel et al., 2008). Cutting edge almost always horizontal in other groups (e.g., Dolichosyne, Peltosyne).
  17. Lateral mental lobes enclosing prementum: (0) absent; (1). Distinctly developed in Adephaga (e.g., Dressler et al., 2010). Absent in other extant and extinct beetles.
  18. Anterior pronotal margin: (0) not distinctly convex and not overlapping posterodorsal head region; (1) distinctly convex and overlapping posterodorsal head region. The convex margin overlapping the posterior head region is an unusual and characteristic feature of †Ademosynidae.
  19. Anterolateral pronotal angles: (0) present; (1) reduced. Almost always distinctly developed (e.g., Ponomarenko, 1969) but reduced in †Ademosynidae. A tendency towards reduction of the anterolateral angle can be also observed in Ommatidae and Cupedidae, and it is entirely missing in Omma rutherfordi Lawrence, 1999 (Lawrence, 1999) and largely obliterated in Tetraphalerus bruchi Heller, 1931 (Friedrich et al. 2008). However, the conditions found in these families differ distinctly from what we observed in ademosynids, and a more or less distinctly recognizable anterolaterally or laterally directed angle is usually present (e.g., Ponomarenko 1969; Baehr, 1979; Tan et al., 2012) (coded as 0 for general of Ommatidae and Cupedidae).
  20. Propleural suture (0) present; (1) absent. Present in Chauliodinae (Maki, 1936), †Tshecardocoleidae, †Permocupedidae, and †Triadocupedinae (Ponomarenko, 1969). Condition in †Rhombocoleidae unclear. Absent in other beetles.
  21. Exposure of propleura: (0) largely or fully exposed; (1) internalized. Internalized in Polyphaga and also in † Peltosyne, † Petrosyne and † Ranis (Yan et al., 2017).
  22. Broad prothoracic postcoxal bridge: (0) absent; (1) present. Present in †Tshecardocoleidae, †Permocupedidae and †Rhombocoleidae (Ponomarenko, 1969; Beutel et al., 2008). Also developed in some few groups not included here (e.g., Rhysodini).
  23. Mesocoxal cavities: (0) not bordered by metanepisterum; (1) bordered by metanepisternum. Metanepisternum forms part of lateral border of mesocoxal cavities in Cupedidae, Ommatidae, †Jurodidea, Myxophaga, and Derodontidae (Kirejtshuk, 1999; Lawrence et al., 2011).
  24. Separation of mesocoxae: (0) moderately widely separated or adjacent; (1) very widely separated. Very widely separated in Myxophaga (e.g., Beutel, 1999) and a species of Ranis (coded as 0&1 for the genus).
  25. Transverse suture of mesoventrite: (0) present; (1) absent. Present in Cupedidae, Ommatidae and Sikhotealinia, and also in some fossil taxa under consideration including † Peltosyne (Yan et al., 2017). Absent in †Catiniidae, †Ademosynidae (in contrast to Ponomarenko, 1969: figure 71c) and † Ranis.
  26. Exposure of metatrochantin: (0) externally visible; (1) internalized or absent. Externally visible in Cupedidae and Ommatidae, and also in the fossil taxa under consideration with the exception of †Catiniidae and †Schizophoridae (narrow element may be exposed in † Catinius; Ponomarenko, 1969).
  27. Shape of penultimate tarsomere: (0) not distinctly bilobed; (1) distinctly bilobed. Bilobed in Cupedidae, Decliniidae and Sialidae (e.g., Lawrence, 1999; Yan et al., 2017).
  28. Sclerotization of fore wings: (0) membranous; (1) transformed into sclerotized elytra. Elytra with epipleura present in beetles with the exception of very few specialized forms (e.g., Beutel and Haas, 2000).
  29. Venation of fore wings: (0) with distinctly curved veins; (1) without distinctly curved veins. Distinctly curved veins only preserved in †Protocoleoptera (e.g., †Tshecardocoleidae; Ponomarenko, 1969).
  30. Elytral sclerotisation pattern: (0) pattern of unsclerotized window punctures; (1) entirely sclerotized. Window puncture pattern present in Cupedidae and Ommatidae, and also in most stem group Coleoptera (e.g., Ponomarenko, 1969). Absent in †Ademosynidae and some other extinct groups, and generally missing in non-archostemataqn beetles (e.g., Ponomarenko, 1969, 2004; Beutel et al., 2008; Yan et al., 2017).
  31. Elytral striae: (0) absent; (0) present. Present in †Ademosynidae, †Peltosynidae, Ranis, Archosyne and some other extinct taxa (Yan et al., 2017). Also occuring in some groups of Adephaga (e.g., Carabidae, major part) or Polyphaga (e.g., Histeridae partim, Elateridae partim) (Lawrence et al., 2011).
  32. Elytral apex: (0) distinctly reaching beyond abdominal apex posteriorly; (1) slightly reaching beyond abdominal apex posteriorly; (2) reaching abdominal apex or shorter. Distinctly reaching beyond abdominal apex in †Tshecardocoleidae and slightly in †Permocupedidae (Ponomarenko, 1969; Beutel, 1997; Beutel et al., 2008). Closely adapted to shape of abdomen in extant beetles with few exceptions.
  33. Abdominal sternite I: exposed; (1) concealed under metacoxae, largely or completely reduced. Reduced in all extant and fossil beetles (e.g., Beutel and Haas, 2000).
  34. Connate abdominal ventrites: (0) none or at least less than 3; (1) 3. Three sternites connate in Adephaga (e.g., Lawrence et al., 2011).
  35. Median ridge on ventrite 1: (0) absent; (1) present. Present in Sikhotealinia, † Jurodes, Cupedidae and Ommatidae (e.g., Beutel et al., 2008).
  36. Arrangement of abdominal sterna: (0) abutting, not overlapping; (1) tegular or overlapping. Overlapping in Cupedidae (Lawrence et al., 2011; Beutel et al., 2008).