Leuctra tenuis (Pictet, 1841)

Grubbs, Scott A., 2015, Leuctra Schusteri, A New Stonefly Species (Plecoptera: Leuctridae) Of The L. Tenuis (Pictet) Group From The Southeastern Usa, Illiesia 11 (12), pp. 147-166 : 148-149

Key to males of the L. tenuis species group

1 Dorsal process on 7 th abdominal tergum tapering to a single, narrowly-rounded posterior lobe, overall shape triangular ( Figs. 10 ‒11, 23‒25) ..……………….………...........…… 2

1’ Dorsal process on 7 th abdominal tergum narrowing little posteriorly, overall shape variable ( Figs. 1‒3 , 19, 34‒36 , 43 , 48 ).……….… 3

2 Subanal lobe ca. ¾ length of the specillum ( Figs. 28‒30, 32 ); specillum simple, lacking spurs or tubercles distally ( Figs. 27 , 31, 33 ) ...…………………………...….… L. tenuis (Pictet)

2’ Subanal lobe ca. equal length to specillum ( Figs. 14‒15 ); specillum with a prominent, laterally-directed spur ( Figs. 12‒13 ) ………………………... L. schusteri sp. n. Grubbs

3 Posterior margin of 7 th abdominal dorsal process terminating along the same plane, overall shape symmetrically-trapezoidal ( Figs. 43 , 48 ) .......................................…………………... 4

3’ Dorsal process on 7 th abdominal tergum variable, overall shape variable ( Figs. 1‒3 , 19, 34‒36 ) ..…………………………………………… 5

4 7th abdominal dorsal process bearing three subtruncate lobes, lateral lobes small, medial lobe ca. 4X wider than lateral lobes ( Fig. 43 ); specillum bearing tubercles distally and along the outer distal margin ( Figs. 44‒47 ); late winter and spring-emergent species ...... L. usdi Grubbs

4’ 7th abdominal dorsal process lacking distinct lateral lobes, essentially straight along posterior margin ( Fig. 48 ); specillum lacking tubercles along distal outer margin and at the tips ( Figs. 49‒52 ); autumn-emergent species ……………………………... L. variabilis Hanson

5 7th abdominal dorsal process bearing three rounded lobes, medial lobe narrowly-rounded posteriorly and nipple-like ( Figs. 34‒36 ); autumn- and winter-emergent species.……………………………..… L. triloba Claassen

5’ 7th abdominal dorsal process lacking distinct lobes, medial posterior portion either broadlyrounded or subtriangular ( Figs. 1‒3 , 19 ); late spring- and summer-emergent species ….....… 6

6 7 th abdominal dorsal lobe broadly rounded posteriorly ( Figs. 1‒3 ); specillum subtriangular distally ( Figs. 4, 7, 9 ), subanal lobes recurved anteriorly, but not at tip ( Figs. 4, 6, 9 ) …………………...…….. L. carolinensis Claassen

6’ 7 th abdominal dorsal process broadly subtriangular posteriorly ( Fig. 19 ); specillum truncate distally ( Fig. 22 ), subanal lobes sharply recurved anteriorly at tips ( Figs. 21‒22 ).……………………………….. L. tenella Claassen

Figures

Figs. 1–3. Leuctra carolinensis. 1, 7th abdominal process, dorsal view, 300X, Connecticut, tributary to Beaver Brook; 2, 7th abdominal process, dorsal view, 350X, Maryland, spring into Little Laurel Run; 3, 7th abdominal process, dorsal view, 350X, Alabama, tributary to Ross Branch.

Figs. 19–22. Leuctra tenella, Pennsylvania, spring into Powdermill Run. 19, 7th abdominal process, dorsal view, 350X; 20, paraprocts, caudal view, 1000X; 21, L. tenella, paraprocts, lateral view, 350X; 22, L. tenella, paraprocts, lateral view, 1500X. sp = specillum, sa = subanal lobe.

Figs 4–9. Leuctra carolinensis. 4, paraprocts, lateral view, 900X, Connecticut, tributary to Beaver Brook; 5, paraprocts, dorsal view, 1000X, Alabama, tributary to Ross Branch; 6, paraprocts, lateral view, 350X, Maryland, Bull Glade Run; 7, paraprocts, lateral view, 1000X, Maryland, Bull Glade Run; 8, paraprocts, lateral view, 350X, Alabama, tributary to Ross Branch; 9, paraprocts, lateral view, 1000X, Alabama, tributary to Ross Branch. sp = specillum, sa = subanal lobe.

Figs. 10–15. Leuctra schusteri sp. n., Kentucky, spring into Smyrna Creek. 10–11, 7th abdominal process, dorsal view, 350X; 12, paraprocts, caudal view, 350X; 13, paraprocts, caudal view, 1500X; 14, paraprocts, lateral view, 500X; 15, paraprocts, lateral view, 1000X. sp = specillum, sa = subanal lobe.

Figs. 16–18. Leuctra schusteri sp. n., Kentucky, spring into Smyrna Creek. 16–17, subgenital plate, ventral view, 350X; 18, vesicle, ventral view, 650X.

Figs. 23–27. Leuctra tenuis. 23, 7th abdominal process, dorsal view, 350X, Maryland, Middle Fork; 24, 7th abdominal process, dorsal view, 350X, Maryland, Youghioghenny River; 25, 7th abdominal process, dorsal view, 350X, Massachusetts, Stillwater River; 26, paraprocts, caudal view, 500X, Indiana, tributary to West Fork Mosquito Creek; 27, paraprocts, caudal view, 1000X, Indiana, tributary to West Fork Mosquito Creek. sp = specillum, sa = subanal lobe.

Figs. 28–33. Leuctra tenuis. 28, paraprocts, lateral view, 500X, Alabama, Hillabee Creek; 29, paraprocts, lateral view, 500X, Massachusetts, Stillwater River; 30, paraprocts, lateral view, 500X, Maryland, Middle Fork; 31, paraprocts, lateral view, 2000X, Maryland, Middle Fork; 32, paraprocts, lateral view, 350X, Tennessee, Cosby Creek; 33, paraprocts, lateral view, 2000X, Tennessee, Cosby Creek. sp = specillum, sa = subanal lobe.

Figs. 34–38. Leuctra triloba. 34, 7th abdominal process, dorsal view, 350X, Alabama, tributary to West Fork Hatchett Creek; 35, 7th abdominal process, dorsal view, 350X, North Carolina, Wine Spring Creek; 36, L. triloba, 7th abdominal process, dorsal view, 500X, Tennessee, tributary to South Suck Creek; 37, paraprocts, caudal view, 750X, North Carolina, Wine Spring Creek; 38, L. triloba, paraprocts, caudal view, 1500X, North Carolina, Wine Spring Creek. sp = specillum, sa = subanal lobe, ll = lateral lobe, ml = medial lobe.

Figs. 43–47. Leuctra usdi, Tennessee, spring into Pinewood Branch. 43, 7th abdominal process, dorsal view, 350X; 44, paraprocts, caudal view, 500X; 45, paraprocts, caudal view, 2000X; 46, paraprocts, lateral view, 350X; 47, L. usdi, paraprocts, lateral view, 1500X. sp = specillum, sa = subanal lobe, ll = lateral lobe, ml = medial lobe.

Figs. 48–52. Leuctra variabilis, Tennessee, Twin Springs. 48, 7th abdominal process, dorsal view, 350X; 49, paraprocts, caudal view, 350X; 50, paraprocts, caudal view, 1500X; 51, paraprocts, lateral view, 350X; 52, L. variabilis, paraprocts, lateral view, 1500X. sp = specillum, sa = subanal lobe.