New specimens from Mid-Cretaceous Myanmar amber illuminate the phylogenetic placement of Lagonomegopidae (Arachnida: Araneae) Author Guo, Xiangbo Author Selden, Paul A. Author Ren, Dong text Zoological Journal of the Linnean Society 2022 2021-06-16 195 399 416 https://www.mendeley.com/catalogue/e9144677-a36a-374f-9b9f-ef35c5f8cd3c/ journal article 61601 10.1093/zoolinnean/zlab027 507433fb-c54c-4c3a-9872-748cd6417b9d 0024-4082 6599779 ODONTOMEGOPS TITAN GUO & SELDEN, 2020 ( FIG. 6 ) Guo et al. (2020) : 2–4, figs 1, 2. Material: Male, specimen no. CNU-ARA-MA2019001 ( holotype ). Locality and horizon: Hukawng Valley, Kachin State , northern Myanmar ; lowermost Cenomanian, Mid-Cretaceous. Description: See Guo et al. (2020) . Epigastric plate with more than 30 epiandrous spigots scattered along median margin of epigastric furrow ( Fig. 6C ). Tracheal spiracle broad, situated on postgastric area behind epigastric furrow, immediately dividing internally into two tracheae ( Fig. 6A, B ). Figure 6. Odontomegops titan ; holotype CNU-ARA-MA2019001: A, basal part of abdomen, ventral view, showing male genitalia and tracheal spiracle; B, schematic drawing of basal ventral abdomen; C, male genitalia, ventral view, showing epigastric furrow and epiandrous spigots (arrows). Scale bars represent 0.5 mm (A, B) and 0.1 mm (C). Remarks: After regrinding and repolishing the holotype of Odontomegops titan , the male genitalia and tracheal spiracle are now shown clearly. They differ from the single, broad opening in Hiatomegops spinalis ( Fig. 3G, H ), in that two small openings are situated on the postgastric area behind the epigastric furrow in Odontomegops titan ( Fig. 6A, B ). We interpret the abdomen of CNU-ARA-MA2019001 as being somewhat modified and broken, thus exposing the internal part of the tracheal spiracle. Hence, we interpret the posterior respiratory system of Odontomegops titan as a single, broad tracheal spiracle, which immediately divides internally into two smaller tracheae.