Isoperla jamesae, Grubbs & Szczytko, 2010

Grubbs, Scott A. & Szczytko, Stanley W., 2010, A New Species Of Eastern Nearctic Isoperla From Alabama And Mississippi, U. S. A. (Plecoptera: Perlodidae; Isoperlinae), Illiesia 6 (17), pp. 241-247 : 243-247

Isoperla jamesae sp. n.

( Figs. 1–13 )

Material Examined. Holotype ♂, USA: Alabama, Lauderdale Co., North Fork Cypress Creek , CR 5, 3 km N Threet, 34.9765°, -87.8252°, 28/IV/2010, S.A. Grubbs . Paratypes: USA, Alabama, Lauderdale Co., same as holotype, 28/IV/2010, S.A. Grubbs, 11♂, 6♀ ; same as holotype, 3/ V /2008, S.A. Grubbs, 3♂; Threet Creek , CR 5, 23 km ENE Waterloo, 34.9559°, - 87.8248°, 3/ V /2008, S.A. Grubbs, 2♀ ; Colbert Creek , CR 14, 16 km NE of Cherokee, 34.8754°, -87.8773°, 4/ V /2008, S.A. Grubbs, 3♂, 8♀ ; Rock (sic) Spring Creek., 6.2 mi S Junct. Hwy 20 and Natchez Trace Pkwy on Pkwy , 6/ V /1971, A.M. James and H.B. Cunningham, 2♂ ; Mississippi: Tishomingo Co., Clear Creek, Hwy 172, 4 mi. east of Iuka , 12/ V /2010, B.P. Stark, 1♂, 1♀ ; same but 18/ V /2009, B.P. Stark, 1♂, 1♀. The holotype is deposited at the United States National Museum, Smithsonian Institution , Washington, D.C. Paratypes are deposited in the following collections: S.A. Grubbs collection (Western Kentucky University), B.P. Stark collection (Mississippi College ), S.W. Szczytko collection ( University of Wisconsin / Stevens Point ) and the Illinois Natural History Survey collection.

Male. Macropterous. Body length 6.0–7.0 mm; forewing length 7.0–8.0 mm. General body color light brown with dark brown markings. Dorsum of head with diffuse wide medium brown bands connecting ocelli and extending to posterior margin of head, terminating in two darker brown spots; interocellar area mostly dark usually with a faint, thin median light line, occasionally completely dark; thin medium brown bands extending anteriorly and deflected inward from median ocellus, bands wider on frons; triocellate ( Fig. 1 ). Antennae and scape dark brown. Pronotum with wide median light stripe; disks medium brown, rugosities darker, thick and rounded; anterior margin dark brown; lateral margins medium brown ( Fig. 1 ). Mesonotum and metanotum medium brown with irregular darker markings. Wings light, veins dark brown. Outer surface of femora light tan, with wide dark brown band near distal end ( Fig. 7 ), numerous small stout setae and occasional longer setae on outer surface; outer surface of tibia medium brown, dark brown dorsal band proximally ( Fig. 7 ), surface with numerous small stout setae and occasional longer setae. Abdominal terga light tan; lateral and dorsal patches of bright red color coloration on segments 1- 7 in fresh material. Tenth tergum weakly sclerotized medially; paraprocts weakly sclerotized, bluntly pointed apically, produced forward only to level of 10 th tergum ( Figs. 4, 5 ). Abdominal sterna light tan; 8 th sternum with a small, weakly sclerotized, low vesicle extending posteriorly to anterior margin of 9 th sternum, ca. 3 times as broad as long ( Fig. 3 ). Aedeagus membranous with paired postero- and antero-dorsal rounded lobes, large antero-medial lobe, paired postero-medial finger-like lobes, paired postero-ventral rounded lobes, and large single postero-basal lobe ( Fig. 6 ). Large postero-basal lobe and baso-median section of aedeagus covered with small, stout sharp spinulae ( Figs. 6 & 6a ); paired postero-ventral lobes and inner posterior margin covered with dense rows of long hair-like spinulae ( Figs. 6, 6b, 6d ); anterior margin above and below postero-ventral lobes with patch of stout spinulae ( Figs. 6, 6c ); patch of concentrated stout, thick spinulae below paired postero-median finger-like lobes ( Figs. 6, 6e ); paired anteromedian lobes fingerlike, deflected ventrally, curved outward at tips, medial patch of sharp stout spinulae below lobes, lateral patches of stout spatula-shaped scales lateral to medial patch ( Figs. 6, 6f , 8, 9); patch of flat scales above postero-median finger-like lobes ( Figs. 6, 6g ); patch of concentrated stout spinulae with apical long hairs above scale patch extending from posterior margin medially to near level of paired posteromedian finger-like lobes ( Figs. 6, 6i ), patch of slender long hair-like spinulae extending below spinulae with apical long hairs to near base of postero-ventral paired lobes ( Figs. 6, 6h ); concentrated patch of short stout, blunt spinulae on postero-apical area ( Figs. 6, 6j ).

Female. Macropterous. Body length 7.0–8.0 mm; forewing length 8.0–9.0 mm. General body coloration, head and pronotal pigmentation patterns similar to male described above, however without abdominal red coloration. Subgenital plate broadly triangular (sometimes rounded apically), 5.6 times as wide as long, produced to near posterior margin of 9 th sternum ( Fig. 2 ).

Egg. General shape nearly round, cross section concave, collar absent ( Figs. 10, 11 ). Color light brown. Length 254 µm, width 228 µm. Chorionic surface covered with numerous small, shallow punctuations; eclosion line, hexagonal follicle cell impressions and ridges absent ( Figs. 10, 11, 12 ). Micropyles positioned near posterior 1/ 3 in a row of 6-8; orifices with thickened flared ridges ( Figs. 12, 13 ).

Etymology. This species is named in honor of Dr. Audrey James, who first recognized this species as new ( James 1972).

Diagnosis. Isoperla jamesae males can be distinguished from other eastern congeners by the unique shape, spinule types and patterns, and unusual finger-like lobes of the aedeagus. Females can be separated from other known eastern Isoperla by the distinctive color pattern of the head with dark brown bands extending from the median ocellus to the frons. Due to the wide variation in the shape of subgenital plate seen among eastern Isoperla species in general, separation based on this character is questionable at this time. The egg is unique from other eastern Isoperla by having a nearly round and concave shape with no follicle cell impressions or ridges visible.

The best diagnostic species character for Nearctic Isoperla is the male aedeagus which needs to be fully everted to discern unique spinule patterns, arrangement of lobes, and sclerotized structures (if present). At this time it is not possible to assign I. jamesae to any eastern Isoperla species group (Szczytko and Kondratieff, in preparation). This species does, however, appear to be aligned with several eastern Isoperla species that have an aedeagus without sclerotized structures and a subtriangular subgenital plate.

Received 29 July 2010, Accepted 12 August 2010, Published 31 August 2010

Remarks. The type locality is a small, upland stream draining a combination of forested and agricultural lands. Amphinemura alabama Baumann , A. nigritta (Provancher) , Leuctra rickeri James , Alloperla caudata Frison , and Haploperla brevis Banks were other stonefly species collected at the type locality with I. jamesae .

Figures

Figs. 1-7. Isoperla jamesae. 1. Adult head-pronotal color pattern (line = 0.5 mm). 2. Female subgenital plate 3. Male 8th and 9th sternum (line = 0.5 mm). 4. Male paraprocts (line = 0.5 mm). 5. Male 8-9 terga (line = 0.5 mm). 6. Male aedeagus (line = 0.5 mm). a. Spinule pattern of postero-basal lobe. b. Spinule pattern of paired postero- ventral lobes and inner margin. c. Stout spinule patch above and below paired postero-ventral lobes. d. Long hair-like spinulae on paired postero-ventral lobes and posterior margin. e. Concentrated stout, thick spinulae below paired postero-median finger-like lobes. f. Paired postero-median finger-like lobes. g. Flat scales above postero-median finger-like lobes. h. Posterior slender, long hair-like spines. i. Stout spinulae with apical long hairs above scale patch. j. Short stout, blunt spinulae on postero-apical area. 7. Male hind leg (line = 0.5 mm).

Figs. 10-13. Isoperla jamesae. 10. Whole egg dorsal view. 11. Whole egg lateral view. 12. Micropyle row. 13. Detail of micropyles.