Odontomegops titan, GUO & SELDEN, 2020

Guo, Xiangbo, Selden, Paul A. & Ren, Dong, 2022, New specimens from Mid-Cretaceous Myanmar amber illuminate the phylogenetic placement of Lagonomegopidae (Arachnida: Araneae), Zoological Journal of the Linnean Society 195, pp. 399-416 : 410-411

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 ).

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.

Figures

Figure 3. Hiatomegops spinalis, holotype CNU-ARA-MA2020002: A, habitus, dorsal view, showing fovea (arrow) and feathery setae (magnified at the top right) on carapace; B, schematic drawing of dorsal habitus; C, habitus, ventral view; D, schematic drawing of ventral habitus; E, cephalothorax, anterior view, showing peg teeth (magnified at the bottom left); F, tibia and tarsus of right pedipalp, lateral view, showing trichobothria (asterisks) and long macrosetae (arrow); G, basal part of abdomen, ventral view, showing female genitalia and tracheal spiracle; H, schematic drawing of basal ventral abdomen; I, spinnerets, ventral view; J, schematic drawing of spinnerets, showing spigots (lower arrow). Scale bars represent 0.5 mm (A, B, C, D), 0.2 mm (E) and 0.1 mm (F, G, H, I, J).

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).