Calileuctra, Shepard & Baumann. The, 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 : 2-4

Generic Diagnosis of Calileuctra

Following is an expanded and updated generic description of Calileuctra larvae from that of Stewart & Stark (2002) that was based on the partial description of C. ephemera larvae. The originally proposed combination of diagnostic Calileuctra characters included: 1) Ab 1-7 divided by a pleural fold, (this character is shared only with the leuctrid genus Megaleuctra Neave , which is much larger and more setose, and with Perlomyia Banks , which has fused, terminally hairless paraprocts and a single stem of the mesosternal Y-ridge), 2) right mandible molar area with 8-10 stalked teeth in side view, (originally described by Stark & Stewart (2002) as a “scraping ridge”), and 3) a double stem of the mesosternal Y-ridge, (this character shared only with Paraleuctra Hanson and Pomoleuctra Stark & Kyzar , but both have much longer terminal cercomere hairs). These original characters are all supported by this study and the generic description, given below, is updated with revised and newly discovered characters, measurements, and illustrations. The further SEM study, with views into the right mandibular cup of C. dobryi , show stalked-tooth ridges similar to those described for C. ephemera by Shepard & Baumann (1995), and comparative side views of the cup of other leuctrid and capniid genera (Stewart & Stark 2002), suggest that the mandibular ridges found in leuctrid genera may be an additional character used in the difficult separation of larvae from these families.

Larval morphology. Body length ♂ 5-7mm, ♀ 6- 8mm, light colored body with little pigmentation and generally few hairs ( Figs. 1 , 21 ). Antennae with 60-64 segments, each with apical circlet of very short hairs or sensillae. Mouthparts Type 1 (herbivorousdetritivorous; Stewart & Stark 2002). Labrum and clypeus with numerous setae. Lacinia triangular and palmate, with 2 large, round-tipped apical teeth, dorsal and ventral rows of sharp spines, and a scalloped palm surface ( Figs. 7, 8 ). Right mandible with short, rounded-tipped apical cusps and molar cup in side view with 8-10 short, stalked teeth ( Figs. 11 , 26 ); these teeth are manifested as curved ridges extending well onto the cup surface ( Fig. 27 ). Left mandible with similar apical cusps; its molar cup with about 12 long, outer, finger-like teeth ( Fig. 12 ) and inner surface with raised, transverse ridges ( Fig. 13 ). Pronotum quadrangular, with no marginal setae and no distinct pattern ( Figs. 1 , 21 ). Mesosternal Yridge with a double stem, arms reaching to posterior corners of furcal pits, and a transverse ridge connecting anterior corners of furcal pits ( Fig. 2 ). Wingpads with few, or no, hairs, 3 or more times longer than wide and with their longitudinal axes nearly parallel to body axis; hind wings slightly shorter than fore wings ( Figs. 1 , 21 ). Legs slightly increasing in size posteriorly; femora and tibiae with appressed, fine clothing hairs, scattered, short thick hairs ( Fig. 14 ), and tarsal segments 1, 2 with a double row of short thick setae ( Fig. 15 ). Abdominal terga without a posterior fringe of setae and variable surface setation between species; pleural fold on segments 1-7 ( Figs. 5 , 23 ). Developing male genitalia evident dorsally and ventrally ( Figs. 1 , 3, 4 ) just prior to emergence. Paraprocts only incompletely fused at base ( Fig. 5 ), each with a pair of terminal hairs ( Figs. 1 , 3, 4, 5 ). Cercal segments 20-22, each with apical circlet of more than 12 stiff setae, half as long as, or longer than, following segment ( Figs. 6 , 20 , 24 ).

Species Accounts of Larvae

The following accounts include: 1) known distribution, 2) larvae, exuviae and adult material examined, and 3) description of characters not addressed in the generic diagnosis above, or that offer specific diagnosis, reinforcement or correction of original character descriptions of C. ephemera by Shepard & Baumann (1995) and Stewart & Stark (2002), and for C. dobryi by Stewart & Drake (2007). Descriptions and illustrations are based on typical, late instar individuals or exuviae from the few populations and individuals that were successfully field associated; therefore, they do not address possible variation of characters.

Figures

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

Figs. 21-24. Calileuctra dobryi larval characters. 21. Habitus (from Stewart & Drake, 2007); scale line = 2mm. 22. Right foreleg. 23. Abdomen, left lateral (from Stewart & Drake, 2007). 24. Basal 16 cercal segments, dorsal (from Stewart & Drake, 2007).

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