Aeshna sp.

Herhold, Hollister W, Davis, Steven R, Degrey, Samuel P & Grimaldi, David A, 2023, COMPARATIVE ANATOMY OF THE INSECT TRACHEAL SYSTEM PART 1: INTRODUCTION, APTERYGOTES, PALEOPTERA, POLYNEOPTERA, Bulletin of the American Museum of Natural History 459 (1), pp. 1-184 : 1-184

Aeshna sp. adult

Figures 31 , 32 (lateral, anterior, posterior); 33 , 34 (dorsal, anterior, posterior), 35 , 36 (ventral, anterior, posterior)

Plates 18 (lateral), 19 (dorsal), 20 (ventral)

DESCRIPTION: HEAD: Numerous air sacs throughout most of the head, creating a complex, interlocking network of tracheae and air sacs. Larger, discernible features outlined here. H-DCT running anteriad, leading to large, nearly hemispherical air sacs that feed numerous H-Oc anteriad. H-VCT similar, supplying a network of ventral air sacs that connect dorsoventrally; H-Lbm ventral to this network.

THORAX: Odonate thoracic morphology, adapted for synchronous (direct) flight musculature, is substantially different from Neoptera. Consequently, assessment of homology for thoracic tracheal morphology is tenuous at best. Several tracheae, particularly those supplying the wings, appear to be homologous, including T2,3- Wbr and T2,3-W-c-r, but the homology of structures found in other winged insects such as T2,3-AWL and T2,3-PWL are not as clear. Many dorsal-ventral tracheae branch from leg tracheae and extend into the flight muscles throughout the pterothorax; it is likely these do not have homologs with Neoptera. T2,3-DLT is differentiable based on homologous connections to spiracles and extension into the abdomen, though the air-sac-based morphology is substantially different from other taxa. As mentioned previously, many tracheae also enter and exit large thoracic air sacs, and apparent valves between these spaces likely facilitate active ventilation. Further research is indicated to accurately locate and effectively visualize these structures.

ABDOMEN: Tillyard’s “visceral” trunk ViLT extending from thorax posteriorly to end at A8-S; ViLT is unsegmented but is numbered A n - ViLT in areas for convenience. ViLT crossing laterally at anterior end of abdomen; this crossover migrating posteriad from immature (see fig. 30 ). A2-ViLT with several ventral branches into viscera, including A2-ViLT-VB. A1..8-S present, with A1..8-SB present. A1-SB long, extending mediad and dorsad from A1-S. A2-SB much shorter; subsequent A3..8-SB present but short. A1-SB dividing into A1-DB, A1-VB, and joining with A1-MLT anteriad and posteriad. A1-DB running dorsad and anteriad, extending into network of leg/wing thoracic tracheae; A1-VB proceeding ventrad and mediad along body wall, joining with T3-VLT anteriad and A1-VLT posteriad in T-shaped junction. A2-S with similar morphology but A2-SB shorter and more dorsal and slightly posterior to A2-DB; subsequent A3..8-S similar to A2-S with very short A n -SB and A n -DB dorsal and posterior. All A n -DB supplying air-saclike A n -DLT, extending from thorax through abdomen as far as A6-DLT; apparent gap between A6-DLT and A7-DLT, followed by narrow, more trachealike A8-DLT extending posteriad. As noted, valvelike structures discernible between adjacent air sacs (see fig. 37 ). A n - MLT extending through abdomen, beginning at thorax and terminating posteriad of A8-S. A n - VLT small and nearly linear, likewise beginning in thorax, connecting with each A n -S via A n -DB and terminating posteriad of A8-S.

Figures

FIGURE 30. Aeshnid immature with longitudinal trunks labeled. Lateral (left), dorsal (middle), and ventral (right) views.

FIGURE 31. Odonata: Aeshnidae anterolateral view.

FIGURE 32. Odonata: Aeshnidae posterolateral view.

FIGURE 33. Odonata: Aeshnidae anterodorsal view.

FIGURE 34. Odonata: Aeshnidae posterodorsal view.

FIGURE 35. Odonata: Aeshnidae anteroventral view.

FIGURE 36. Odonata: Aeshnidae posteroventral view.

FIGURE 37. Aeshnidae with valve. Direct screen capture from 3D Slicer.