Pteronarcys, Newman, 1838

Myers, L. W. & Kondratieff, B. C., 2017, Larvae Of North American Species Of Pteronarcys (Plecoptera: Pteronarcyidae), Illiesia 13 (16), pp. 192-224 : 201-202

KEY TO MATURE LARVAE

1 Abdominal segments with conspicuous lateral projections ( Figs. 13, 14 , 17 , 25 , 27 , 50, 51, 53 , 54 , 58, 59, 61 , 62 , 66 ) ………………………………… 5

1’ Abdominal segments without lateral projections ( Figs. 18 , 23 , 28 , 36 , 37 , 44 , 45 , 49 ) ……………... 2

2 Supra-antennal plate developed into a semicircular ridge ( Figs. 16 , 30 , 39 , 46 , 48 , 55 , 60 , 63 ); APP weakly developed, APPMH/APPBW <1, and with rounded apices ( Figs. 31 , 36 , 40 , 44 , 47 , 49 ) ………………………………………………… 3

2’ Supra-antennal plate developed into a pointed semi-lunate conical projection visible dorsally ( Figs. 19 , 22 ); APP strongly developed APPMH/APPBW> 1, with pointed apices ( Figs. 20, 21 , 23 ) …………………………… P. californica

3 APP oriented laterally occasionally appearing reflexed distally ( Figs. 31 , 32, 33, 34 , 36 , 40 , 41, 42 , 44 ) ……………………………………………........ 4

3’ APP oriented anterolateral at a 45° angle ( Figs. 47 , 49 ) ……………………………….….. P. princeps

4 Convex bulge on lateral margin of pronotum sometimes present but does not exceed the level of pronotal projections ( Figs. 40 , 41 , 44 ); male larvae with rearward projecting process on abdominal sternum 9 triangular in shape and with sides nearly converging, resulting angle> 50° (63.91 ± 13.16) ( Figs. 38 , 43 ) ……..…. P. pictetii

4’ Convex bulge on lateral margin of pronotum produced often exceeding level of pronotal projections ( Figs. 32 , 36 ); male larvae with rearward projecting process on abdominal sternite 9 rectangular and with nearly parallel sides, resulting angle <39 (33.11 ± 5.16) ( Figs. 29 , 35 ) ………………………………….......... P. dorsata

5 Prominent acute process on each mesothoracic wingpad lateral margin ( Figs. 24 , 27 ); supraantennal plate developed into pointed, semilunate conical projections ( Fig. 26 ); abdominal projections with curved inner margins strongly developed on segments 1-8 ( Figs. 25 , 27 ), pronotal projections well developed with curved margins and sharp apices.; APPMH/APPBW ≥ 1.19 ( Figs. 24 , 27 ) ……………………………...…………. P. comstocki

5’ Prominent acute process absent from each mesothoracic wingpad, lateral margins smooth ( Figs. 15 , 17 , 57 , 66 ); supra-antennal plate developed into a low semi-circular ridge ( Figs. 16 , 55 , 60 , 63 ); APP not strongly developed, apices bluntly rounded; APPMH/APPBW ≤ 1.16 ( Figs. 15 , 17 , 52 , 57 , 65 , 66 ) ………………….…... 6

6 Lateral abdominal projections on AB7 and AB8 reduced and inconspicuous, AB8 POM/SW <0.13; APPA relatively obtuse ≥ 55° and with rounded corners ( Figs. 52 , 57 , 65 , 66 ) …….……. 7

6’ Lateral abdominal projections conspicuous and well developed on AB1-8, AB8 POM/SW ≥ 0.13 ( Figs. 1 , 13, 14 ); APPA more acute <55° (Figs., 15, 17) ……………………….……….......……. P. biloba

7 Measured in dorsal view AB4 POM/SW <0.15; AB6 POM/SW <0.12, lateral abdominal projections of AB5-7 nearly indiscernible, projecting past the posterior margin of the segment minimally in lateral view ( Figs. 58, 61 ) ………………………………….... P. scotti (in part)

7’ Measured in dorsal view AB4 POM/SW ≥ 0.15; AB6 POM/SW> 0.12, lateral abdominal projections of AB5-7 well defined, rugose and triangular shaped in lateral view, the dorsal edge projecting caudally parallel to the lateral surface of the segment ( Figs. 50, 53 ) or lateral abdominal projections of AB5-7 nearly indiscernible, projecting past the posterior margin of the segment minimally in lateral view ( Figs. 58, 61 ) ………………………….……….......................….. 8

8 In dorsal view abdominal projections of AB1-7 well developed with the largest projections possessing a convex outer margin, appearing hook-shaped in dorsal view ( Figs. 51 , 54 , 57 ); AB5-7 well defined, rugose and triangular shaped in lateral view, the dorsal edge projecting caudally parallel to the lateral surface of the segment ( Figs. 50, 53 ), antennae with a distinctive medial yellow band ( Figs. 56 , 57 ) …………………………………………… P. proteus

8’ In dorsal view lateral abdominal projections of AB1-7 less developed, outer margins of largest projections nearly straight ( Figs. 59 , 62 , 66 ), lateral abdominal projections of AB5-7 nearly indiscernible, projecting past the posterior margin of the segment minimally in lateral view ( Figs. 58, 61 ), antennae lacking distinctive yellow band ( Figs. 64 , 66 ) …...............…. P. scotti (in part)

Figures

Fig. 13-16. Pteronarcys biloba. 13. Abdomen lateral view; New York: Franklin Co., N. B. Saranac River. 14. Abdomen dorsal view; New York: Franklin Co., N. B. Saranac River. 15. Head and Pronotum dorsal view; New York: Franklin Co., N. B. Saranac River. 16 Supra-antennal process dorsal view; New York: Franklin Co., N. B. Saranac River.

Fig. 17. Pteronarcys biloba - Larval habitus; New York: Clinton Co., Tributary to Canfield Brook.

Fig. 24-26. Pteronarcys comstocki. 24. Pronotum and thorax dorsal view; New York: Essex Co., Tributary of Ausable River. 25. Abdomen dorsal view; New York: Essex Co., Tributary of Ausable River. 26. Supraantennal process; New York: Essex Co., Tributary of Ausable River.

Fig. 27. Pteronarcys comstocki. Larval habitus; Virginia: Highland Co., Back Creek.

Fig. 50-53. Pteronarcys proteus. 50. Abdomen lateral view; New York: Essex Co., Roaring Brook. 51. Abdomen dorsal view; New York: Essex Co., Roaring Brook. 52. Head and pronotum dorsal view; New York: Essex Co., Roaring Brook. 53. Abdomen lateral view; Virginia: Botetourt Co., Bear Wallow Creek.

Fig. 54-56. Pteronarcys proteus. 54. Abdomen dorsal view; Virginia: Botetourt Co., Bear Wallow Creek. 55. Supra-antennal process; New York: Essex Co., Roaring Brook. 56. Antennae; New York: Delaware Co., Spring-fed tributary to Emory Brook.

Fig. 58.-61. Pteronarcys scotti. 58 Abdomen lateral; Tennessee: Sevier Co., Little River. 59. Abdomen dorsal view; Tennessee: Sevier Co., Little River. 60. Supra-antennal process; Tennessee: Sevier Co., Little River. 61. Abdomen lateral view; Tennessee: Carter Co., Cades Cove Creek.

Fig. 62-65. Pteronarcys scotti. 62. Abdomen dorsal view; Tennessee: Carter Co., Cades Cove Creek. 63. Supraantennal process; Tennessee: Carter Co., Cades Cove Creek. 64. Antennae; Tennessee: Sevier Co., Little River. 65. Pronotum; Tennessee: Sevier Co., Little River.

Fig. 66. Pteronarcys scotti. Larval habitus; North Carolina: Macon Co., Cullasaja River.

Fig. 18-21. Pteronarcys californica – 18. Abdomen dorsal; Colorado: Larimer Co., Poudre River. 19. Supraantennal process dorsal view; Colorado: Larimer Co., Poudre River. 20. Head and pronotum dorsal view; Colorado: Larimer Co., Poudre River. 21. Head and thorax dorsal view; Colorado: Larimer Co., Poudre River.

Fig. 23. Pteronarcys californica. Larval habitus; Colorado, Grand Co., Colorado River.

Fig. 28-31. Pteronarcys dorsata. 28. Abdomen dorsal view; Michigan: Otsego Co., West Branch Sturgeon River. 29. Ventral view of process on AB 9 of male; Michigan: Otsego Co., West Branch Sturgeon River. 30. Supra-antennal process; Michigan: Otsego Co., West Branch Sturgeon River. 31. Pronotum dorsal view; Michigan: Otsego Co., West Branch Sturgeon River.

Fig. 36. Pteronarcys dorsata. Larval habitus; Mississippi: Simpson Co., Westville Creek.

Fig. 37-40. Pteronarcys pictetii. 37. Abdomen dorsal view; Nebraska: Hall Co., Platte River. 38. Abdomen ventral view; Wisconsin: Dunn Co., Red Cedar River. 39. Supra-antennal process; Nebraska: Hall Co., Platte River. 40. Pronotum dorsal view; Nebraska: Hall Co., Platte River.

Fig. 44. Pteronarcys pictetii. Larval habitus; Nebraska: Deuel Co., South Platte River.

Fig. 45-47. Pteronarcys princeps. 45. Abdomen dorsal view; California: Butte Co., Butte Creek. 46. Supraantennal process; California: Butte Co., Butte Creek. 47. Head and pronotum dorsal view; California: Butte Co., Butte Creek.

Fig. 49. Pteronarcys princeps - Larval habitus; California: Siskiyou Co., Big Springs Creek.

Fig. 48. Pteronarcys princeps. Supra-antennal process; California: Siskiyou Co., Big Springs Creek.

Fig. 22. Pteronarcys californica. Supra-antennal process; Colorado, Grand Co., Colorado River.

Fig 32-34. Pteronarcys dorsata. 32. Pronotum dorsal view; Virginia: Montgomery Co., Little River. 33. Pronotum dorsal view; New York: Sullivan Co., Delaware River. 34. Pronotum dorsal view; Canada: Northwest Territories, Source of Mackenzie River, Great Slave Lake.

Fig. 41-42. Pteronarcys pictetii. 41. Pronotum dorsal view; Nebraska: Red Willow Co., Republican River. 42. Pronotum dorsal view, Wisconsin: Dunn Co., Red Cedar River.

Fig. 43. Pteronarcys pictetii. Process of male sternum 9; Nebraska, Deuel Co., South Platte River.

Fig. 35. Pteronarcys dorsata. Process of male sternum 9; Mississippi: Simpson Co., Westville Creek.

Fig. 57. Pteronarcys proteus. Larval habitus; Massachusetts: Berkshire Co., Wright Brook.

Fig. 1. Pronotal projection morphometrics; APP Angle (Anterior Pronotal Projection Angle), APPMH (Anterior Pronotal Projection Median Height), APPBW (Anterior Pronotal Projection Basal Width), PPP Angle (Posterior Pronotal Projection Angle), PPMH (Posterior Pronotal Projection Median Height), PPPBW (Posterior Pronotal Projection Basal Width). Fig. 2. Abdominal projection morphometrics; SL (Segment Length), SW (Segment Width), POM (Projection Outer Margin), PIM (Projection Inner Margin). Fig. 3. Process of AB9 in male of P. pictetii showing measured AAMP angle.