Calileuctra ephemera Shepard & Baumann, 1995

Stewart, Kenneth W., Stark, Bill P. & Serpa, Larry L., 2013, Larvae Of The Two North American Species Of Calileuctra (Plecoptera: Leuctridae), Illiesia 9 (1), pp. 1-13 : 7-8

Calileuctra ephemera Shepard & Baumann

( Figs. 1-6 , 7-12 , 13-18 , 19-20 , 33 )

Distribution and collection site descriptions.

Known from Putah Creek in Lake Co., tributaries and the main channel of Whitlow Creek, Mendocino Co., and the type locality, Capell Creek tributary in Napa Co., all in California. Capell Creek tributary and Putah Creek sites are both in the Putah Creek drainage but separated by about 34 miles. The type locality ( Fig. 33 ) was described by Shepard & Baumann (1995), whereas the latter site consists of two small, adjacent stream channels; the larger, southern channel, from which the female specimen was collected, has a closed riparian canopy composed primarily of California Bay ( Umbellularia californica (Hook & Arn.) Nutt. ), Big-leaf Maple ( Acer macrophyllum Pursh ), Blue Oak ( Quercus douglasii Hook & Arn. ), Black Oak ( Q. kelloggii Newberry ), Canyon Live Oak ( Q. chrysolepis Liebm. ) and California Buckeye ( Aesculus californica (Spach) Nutt. ). Additional shading occurs from the surrounding mixed oak forest along adjacent steep slopes. Herbaceous streamside vegetation consists mostly of California Fescue ( Festuca californica Vasey ). Adult Malenka depressa (Banks) , Sweltsa pisteri Baumann & Bottorff and Soliperla thyra (Needham & Smith) were swept from riparian vegetation by author Serpa, and larvae of Oemopteryx vanduzeea (Claassen) and an undetermined Isoperla were collected on other sample dates.

The Whitlow Creek tributary sites are located about 43 miles northwest of the Putah Creek site (or 74 miles northwest of the type locality) on property owned by the Conservation Fund in the Garcia River watershed, Mendocino County, California, and the site receives additional protection from an easement held by the Nature Conservancy. The intermittent tributaries flow through steep forested terrain, becoming relatively level near their junctions with the main channel of Whitlow Creek which retains water at least 9 months of the year. The tributaries flow for about 4-5 months of the year but probably have hyporheic springs (suggested by the presence of blind unpigmented amphipods, Stygobromus sp. and the blind isopod, Callasellus californicus (Miller)) which reach the surface only during the wet months. The portion of the forest in which Calileuctra specimens were collected includes a heavy oak component along with California Bay, Oregon Ash ( Fraxinus latifolia Benth. ), Tan Oak ( Notholithocarpus densiflorus (Hook & Arn.) Manos, Cannon & S.H.Oh ), California Buckeye, Big-leaf Maple and young Douglas fir. Oregon White Oak ( Quercus garryana Douglas ex. Hook.) grow on the adjacent slopes, often extending over the stream and providing additional shading. Seventy six adult C. ephemera adults were swept or beat from riparian vegetation with the vast majority of specimens found on herbaceous Festuca , rushes or ferns. All larvae were collected from pools where the sand-gravel substrate could be disturbed to a depth of at least 3 inches. Other stoneflies collected with Calileuctra include members of the Capnia ventura Nelson & Baumann complex (R.W. Baumann in litt.) and Mesocapnia projecta (Frison) .

Material examined. CALIFORNIA: Lake Co., Putah Creek, Hwy 175, 3.5 mi N Middletown, 23.00 mile marker, 17 May 1998, C.R. Nelson, B. Stark, S.W. Szczytko, I. Sivec, 1♀ (C.R. Nelson Collection). Mendocino Co., 15 collections by L.E. Serpa, 17-II- 2010 to 16-IV-2012, mainly tributary complex of Whitlow Creek, 38 ° 54’41.4” - 38 ° 55 ’ 0 ’’ N, 123 ° 28 ’ 14” - 123 ° 28 ’ 38 ” W, 131.4 - 204.5 m elevation, 33♂, 47♀, 15 larvae. One pair of larvae and most adults deposited in L.E. Serpa collection, 1♂ and 2♀ deposited in R.W. Baumann collection, Monte L. Bean Museum, Brigham Young University, Provo, UT, and remaining larvae and a few adults deposited in B.P. Stark collection, Mississippi College, Clinton, MS.

Characters of mature larvae. Color, pigmentation ( Fig. 1 ), lacinia ( Figs. 7, 8 ), general body, leg, and cercal setation ( Fig. 1 ,) and mouthparts, typical of genus. Body length ♂ 5-6.5 mm, ♀ 6-8 mm. Head capsule width ♂ 0.66-0.75 mm, ♀ 0.75-0.84 mm. Antennal segments 60-64, each with very short apical circlet of hairs or sensillae. Lacinia triangular and palmate, with 2 rounded-tipped apical teeth, 8-10 dorsal and ventral rows of long, sharp spines, a long, trichoid sensilum arising from the base of one apical tooth (and as long as the tooth) ( Fig. 9 ), and a scalloped palm surface. Right mandibular molar cup, in side view, with 8-10 stalked teeth that are manifested in both Calileuctra species as stalked ridges extending onto the cup (see inside surface of C. dobryi cup, Fig. 27 ). Left mandibular molar cup with about 12 long, curved, comb-like outer sharp teeth, and 3 or 4 raised transverse ridges (that in Fig. 13 are probably well worn). Mesosternum with a double stem of its Y-ridge ( Fig. 2 ). Inside fore wingpad length ♂ 0.66-0.75 mm, ♀ 0.72-0.96 mm; inside hind wingpad length ♂ 0.51-0.63 mm, ♀ 0.60- 0.78 mm. Foreleg femoral and tibial surface with sparse, short, stiff hairs, fine appressed clothing hairs, and few if any fringe hairs ( Figs. 1 , 14 ); apex of tibia with 2 heavy apical spines; tarsal segments 1, 2, with double ventral rows of short spines ( Fig. 15 ). Abdominal terga with scattered, appressed clothing hairs, and segments 7-10 with thick, bristle-like setae, especially laterally, in dorsal view ( Figs. 16-18 ); terga 7-8 ( Fig. 17 ) without 2 diverging rows of short, thick sensillae (as present in C. dobryi , see Figs. 30 , 31 ). Developing male genitalia evident dorsally and ventrally just prior to emergence ( Figs. 3, 4 ). Cercal segments 20-24 ( Fig. 6 ), each, except terminal few, with apical circlet of more than 15 stiff hairs ( Fig. 20 ); hairs of basal segments only about half the length of following segment ( Fig. 19 ).

Figures

Fig. 1. Calileuctra ephemera pharate larval male habitus. Scale line = 2 mm.

Figs. 2-6. Calileuctra ephemera larval characters. 2. Male mesosternum. 3. Pharate male terminalia, dorsal. 4. Pharate male terminalia, ventral. 5. Female terminalia, ventral. 6. Cercus, dorsal. Scale line = 1mm, arrows = developing male genitalic features.

Figs.7-12. Calileuctra ephemera larval characters. 7. Lacinia, ventral. 8. Lacinia and galea, lateral. 9. Lacinia apex, ventral. 10. Right mandible, lateral. 11. Left mandible, outside. 12. Left mandible outside molar cup teeth. Arrows = molar cup.

Figs.13-18. Calileuctra ephemera larval characters. 13. Left mandible molar cup. 14. Left foreleg femur and tibia, anterior. 15. Left foreleg tarsus, ventral. 16. Abdominal terga 8-10. 17. Abdominal tergum 7. 18. Abdominal tergum 9.

Figs.19-20. Calileuctra ephemera cerci. 19. Basal 4 segments, dorsal. 20. Cercal segments 5, 6.

Figs. 33-34. Intermittent headwater habitats of Calileuctra. 33. Capell Creek, type locality of C. ephemera. 34. Arroyo Sequit, habitat of C. dobryi. No larvae found in rainwater pools, February 2000.

Figs. 25-30. Calileuctra dobryi larval characters. 25. Right lacinia, ventral. 26. Right mandibular molar cup, outer margin. 27. Ridges of right mandibular molar cup. 28. Worn left mandibular molar cup. 29. Abdominal tergum 7, left side, arrow = sensilla row. 30. Abdominal tergum 8, diverging rows of short, thick sensillae.

Figs.31-32. Calileuctra dobryi larval characters. 31. Abdominal tergum 8, right side. 32. Basal cercal segments, dorsal.