Allocapnia muskogee, Grubbs & Sheldon, 2008

Grubbs, Scott A. & Sheldon, Andrew L., 2008, Allocapnia Muskogee And A. Menawa, New Species Of Snowflies (Plecoptera: Capniidae) From The Talladega National Forest Region Of Eastern Alabama, U. S. A., Plus Four New State Records, Illiesia 4 (11), pp. 99-109 : 99-104

Allocapnia muskogee sp. n.

( Figs. 1-8 )

Material examined. Holotype ♂ and paratype ♀, U.S.A., Alabama, Cleburne Co., unnamed tributary to Swan Branch , Shinnabone Creek , Talladega National Forest , 24 km SW Heflin, 28 December 2007, S.A. Grubbs ( INHS). Additional paratypes: same but 9 ♂, 4 ♀ ( WKU); same but 17 February 2003, 1 ♂, S.A. Grubbs ( WKU). Clay Co. , unnamed tributary to Cheaha Creek , Talladega National Forest , 19 km N Ashland, 33.4397°N, 085.8387°W, 4 December 2006, 1 ♂, A.L. Sheldon ( WKU). Cleburne Co. , unnamed tributary to South Fork Terrapin Creek , Talladega National Forest , 33.8220°N, 085.5148°W, 22 December 2007, 2 ♂, A.L. Sheldon ( WKU); unnamed tributary to unnamed tributary to South Fork Terrapin Creek , Talladega National Forest , 4 km S Vigo, 33.8865°N, 085.5559°W, 26 January 2008, 2 ♂, 2 ♀, S.A. Grubbs ( WKU). Georgia, Lumpkin Co., fast stream, 12 mi NW Cleveland, 30 December 1964, 1 ♂, Hensley and Smith ( INHS, Catalog No. 11964).

Male. Body length 3.5–5.0 mm. Wings reaching 6 th to the 9 th abdominal terga. Seventh abdominal terga unmodified. Dorsal process of 8 th terga markedly produced, nearly perpendicular to the plane of the abdomen ( Figs 1–2 ); process with tuberculate transverse ridge that is partially ( Figs. 3–4 ) to nearly completely separated medially ( Fig. 5 ), with lobes that appear subtriangular in dorsal aspect ( Figs. 3, 5 ) to subtruncate in anterodorsal aspects ( Fig. 4 ). Apical limb of epiproct 2X length of basal limb, moderately and roundly expanded distal half laterally ( Fig. 1 ), nearly parallel-sided and unmodified dorsally ( Figs. 6–7 ).

Female. Body length 4.0–5.5 mm. Wings reaching 7 th terga to beyond tip of abdomen. Eighth abdominal sterna darkly sclerotized medially, only slightly sclerotized laterally, terminating in triangular projection posteriorly; separated from 7 th sterna by membrane ( Fig. 8 ).

Etymology. The specific name, used as a noun in apposition, is in reference to the indigenous Muskogee, or Creek, Native Americans who occupied the upper Coosa and Tallapoosa River valleys flanking the Talladega National Forest area prior to European settlement. The common name, Muskogee snowfly, is proposed for this species ( Stark et al. 1998)

Diagnosis. Allocapnia muskogee is most similar to A. wrayi Ross and A. mystica Frison , the only two members of the A. mystica species group ( Ross & Ricker 1971). Allocapnia zekia was described by Ross (1964) as a possible local variant of A. wrayi and also placed in the A. mystica group (Ricker & Ross 1971), but was subsequently synonymyzed with A. wrayi by Kondratieff & Kirchner (1982). Allocapnia muskogee is included in the A. mystica group.

Allocapnia muskogee is distinguished from the other two members of this group most easily by details of the epiproct, in both lateral and dorsal aspects. The ratio of the apical limb length to the basal limb length varies across the A. mystica group. The apical limb of A. mystica is markedly shorter than the basal limb, approximately 0.75X the length ( Figs. 17–18 ). In contrast, the apical limb of A. muskogee is 2X the length of the basal segment ( Fig. 1 ) and 1X – 1.5X for A. wrayi ( Figs. 9–10 ). Kondratieff & Kirchner (1982) illustrated the variability of the epiproct for Maryland and Virginia specimens of A. wrayi , depicting apical to basal limb ratios of 1.5X (their Fig. 1 ) and 1X (their Fig. 2 ), which is similar to the 1.5X ratio shown here for two separate series of specimens from western Maryland ( Figs. 9–10 ). Additional specimens of A. wrayi examined from Maryland, Virginia, North Carolina and South Carolina pertain easily to this concept.

In lateral aspect the apical epiproct limb of A. muskogee is rounded distally ( Figs. 1 ), and differentiated easily from both A. wrayi and A. mystica . For A. wrayi the distal end of the epiproct is truncate with a raised mid-dorsal keel ( Figs. 9–10, 13– 15 ), while the apical half of the epiproct of A. mystica bears a subdistal notch ventrally ( Figs. 17–18 ). When viewed dorsally the epiproct apical limb of A. muskogee is parallel- or nearly parallel-sided and broadly rounded distally ( Figs. 6–7 ). In contrast, the epiproct apical limb of A. wrayi is spatulate ( Figs. 13– 15 ) and for A. mystica the epiproct apical limb tapers markedly distally.

The dorsal process of the 8 th abdominal terga of A. muskogee , A. wrayi , and A. mystica are similar and provide a less objective means of differentiating between species. The dorsal process lobes of A. muskogee vary from subtriangular to truncate ( Figs. 3–5 ) while the lobes are more rounded for both A. wrayi ( Figs. 11–12 ) and A. mystica ( Figs. 19–20 ).

Females of A. muskogee can be distinguished from A. wrayi and A. mystica by the posterior triangular projection of the 8 th abdominal sterna ( Fig. 8 ). Allocapnia mystica bears a broadly rounded posterior margin ( Fig. 24 ) while the posterior margin of A. wrayi varies from broadly rounded to slightly subtriangular ( Fig. 16 ). Ross & Ricker (1971) did not distinguish the females of A. mystica and A. wrayi .

Although A. mystica is distributed broadly across the unglaciated landscape east of the Mississippi River ( Kondratieff & Baumann 2000; Stark et al. 2008) and is common throughout Alabama ( James 1972), it is not a resident of upland or montane streams in the Talladega National Forest area. Allocapnia wrayi is regionally distributed in small, upland streams from southern Pennsylvania south to northwestern South Carolina, and has yet to be collected west of the Appalachian Mountains ( Ross & Ricker 1971; Kondratieff & Baumann 2000; Stark et al., 2008). The single male specimen of A. muskogee from northern Georgia currently represents the northern end of its range.

Remarks. The type locality is a small, intermittent stream situated within a broad, flat valley. The only other stonefly species collected with A. muskogee , and only from the tributary to Cheaha Creek site, were A. aurora Ricker , A. menawa n.sp., and A. recta (Claassen) .

Figures

Figs. 1–8. Allocapnia muskogee. 1. Male terminalia, lateral, SEM micrograph, 200X, 2. Male terminalia, lateral, SEM micrograph, 200X, 3. Male terminalia, dorsal, SEM micrograph, 200X, 4. Male terminalia, dorsoanterior, SEM micrograph, 200X, 5. Male terminalia, dorsal, SEM micrograph, 200X, 6. Male terminalia, dorsal, SEM micrograph, 200X, 7. Male terminalia, dorsal, SEM micrograph, 750X, 8. Female terminalia, ventral.

Figs. 17–24. Allocapnia mystica (17, 19, 21, 23: U.S.A., Indiana, Perry Co., East Deer Creek, 3 January 2000; 18, 20, 22, 24: U.S.A., Alabama, Lawrence Co., West Flint Creek, 27 December 2007). 17. Male terminalia, lateral, SEM micrograph, 200X, 18. Male terminalia, lateral, SEM micrograph, 200X, 19. Male terminalia, dorsal, SEM micrograph, 150X, 20. Male terminalia, dorsoanterior, SEM micrograph, 200X, 21. Male terminalia, dorsal, SEM micrograph, 200X, 22. Male terminalia, dorsal, SEM micrograph, 200X, 23. Male terminalia, dorsal, SEM micrograph, 750X, 24. Female terminalia, ventral, SEM micrograph, 150X.

Figs. 9–16. Allocapnia wrayi (9, 12, 14, 15: U.S.A., Maryland, Allegany Co., White Sulphur Run, 16 January 1996; 10, 11, 13, 16: U.S.A., Maryland, Washington Co., Little Tonoloway Creek, 17 December 1995). 9. Male terminalia, lateral, SEM micrograph, 200X, 10. Male terminalia, lateral, SEM micrograph, 200X, 11. Male terminalia, dorsal, SEM micrograph, 200X, 12. Male terminalia, dorsoanterior, SEM micrograph, 200X, 13. Male terminalia, dorsal, SEM micrograph, 200X, 14. Male terminalia, dorsal, SEM micrograph, 200X, 15. Male terminalia, dorsal, SEM micrograph, 750X, 16. Female terminalia, ventral, SEM micrograph, 150X.