Agapetus tricornutus Etnier, Parker, and Baxter, 2010

Etnier, David A., Parker, Charles R., John T. Baxter, Jr., Long, Todd M. & Drive, News Sentinel, 2010, A review of the genus Agapetus Curtis (Trichoptera: Glossosomatidae) in eastern and central North America, with description of 12 new species, Insecta Mundi 2010 (149), pp. 1-77 : 42-44

Agapetus tricornutus Etnier, Parker, and Baxter new species

Fig. 27a, 27b, 27c . Map 27

Type material. Holotype, male, length 4.7 mm, EX UT 1.464 . stream 1.5 rd mi w of US 11 on continuation of St. Clair co rd 30, 33.7345 o N, 86.5379 o W, Jefferson Co., AL, 13 April 1999, emerged 17 April 1999, D. A. Etnier. ( NMNH)

Allotype, female pupa, taken with holotype, emerged 17 April 1999. ( NMNH)

Paratopotypes, EX UT 1.464 : CASC, 1 male pupa, 1 larva, 1 prepupa ; CUAC, 1 MMTmale, 1 MMT female, 1 larva, 1 prepupa ; INHS, 1MMTmale, 1 MMT female, 1 larva, 1 prepupa ; ROME, 1 MMTmale, 1 MMT female, 1 larva, 1 prepupa ; SCHC, 1 MMT male pupa, 1 larva, 1 prepupa ; UMSP, 1 MMTmale, 1 female pupa, 1 larva, 1 prepupa ; NMNH, 1 male pupa, 1 larva, 1 prepupa. Remaining in UT 1.164 are 1 MMTmale, 1 MMT male pupa, 1 MMT female pupa, 1 larva, and 3 prepupae .

Additional paratypes, EX UT 1.500 , Ohatchee Cr. trib. at Kays Ferry Road, 0.6 rd mi n of jct. Hollingsworth Road and New Liberty Road, access via Seven Springs Road, ne of AL 204, Calhoun Co., AL, 6 May 1999. CASC, 1 MMT female pupa ; SCHC, 1 MMT female pupa. Remaining in UT 1.500 are 2 males, 2 MMT males, and 4 MMT female pupae .

Additional material examined. Alabama, St. Clair Co.: UT 1.463 , spring run 2.4 rd mi n of co rd 30, s of Springville , 13 April 1999, 1 male + 2 female mature pupae/adults ; UT 1.490 , spring run at US 11 in Springville , 13 April 1999, 2 male + 1 female mature pupae/adults .

Diagnosis. The three prominent spines or denticles (2 dorsal and vertical, 1 ventral and horizontal, none between posterioventral and posteriodorsal corner) associated with the posterior margin of segment X (lateral view) separate this species from all others in central and eastern North America. Most similar to A. alabamensis (which has 4-9 prominent denticles on X, many on posterior border), and further differing in having ventral margin of X straight on distal 3/4 (distal 1/4 decurved in A. alabamensis ).

Description. Male. Length 4.0- 5.5 mm (n = 7). Male genitalia: Lateral view ( Fig. 27a ), segment IX anterior margin straight, slanting down and forward to middle at 45 o, lower 1/2 slightly convex, sloping down and back at 60 o to convex ventral margin; posterior margin convex and nearly vertical; dorsal margin 1/2 length of ventral margin, sloping down and back at 20 o. Preanal appendage clavate, 1/2 length of inferior appendage, its maximum depth (posterior to mid-length) 1/3 length; distal 1/2 and end with about 12 long setae. Sides of X sclerotized, ventral arms more opaque; dorsal margin with slight concavity at base, then straight to second concavity anterior to anteriodorsal denticle, then more deeply concave to base of posteriodorsal denticle. Ventral margin horizontal to sloping downward to swelling at basal third, then upward (145 o angle with base) to posterioventral denticle. Terminal denticles 3, one at posterioventral corner nearly horizontal, curved upward; largest denticle vertical, at posteriodorsal corner; third denticle also vertical, subequal to ventral denticle, and anterior to largest denticle. A few scattered serrations occasionally present along posterior border of X. Inferior appendage rhomboid, length = 3.0 times depth; upper margin straight, nearly parallel to convex lower margin, distal end angles down and forward at 55 o; a submarginal black denticle apparent on inner surface at posteriodorsal corner, and heavily sclerotized ridge associated with posterioventral corner visible as a dark line.

Dorsal view ( Fig. 27b ). Segment IX with anterior margin broadly and deeply concave, thickened, its mid-length 0.4 times that of preanal appendage, posterior margin straight, poorly differentiated from X, and with triangular emargination barely visible on midline. Preanal appendages parallel to or slightly divergent from body axis, inner margin concave near base, convex distally, outer margin straight except may diverge slightly at pointed, distal end. Sclerotized inner margins of X narrowly separated by dorsal membranous area and convergent to U- or V-shaped (20 o angle) basal fusion. Dorsolateral and ventrolateral margins of X nearly parallel; posteriodorsal denticles with tips incurved; posterioventral denticle with tip curved outward. Inferior appendages (not shown) with denticle near posteriodorsal margin pointed, transverse.

Ventral view ( Fig. 27c ). Anterior margin of IX concave, posterior margin with angular extension (90 o) between inferior appendage bases; heart-shaped to triangular depigmented area on IX anterior to inferior appendage bases bordered anteriad by transverse row of setae. Inferior appendages with bases slightly swollen, outer margins slightly concave near middle, slightly divergent to rounded tip; inner margins in contact at base, straight and divergent (30 o from each other) to mid-length; at mid-length a tiny dark denticle marks the anterior end of a concave, heavily sclerotized ridge that diverges (30 o angle from body axis) to posterioventral angle of inferior appendage where an additional weak denticle is present; the ridge then abruptly more concave, less darkly pigmented, and more divergent to base of submarginal posteriodorsal denticle. Ventral arms of X (not shown) converge from base to meet or nearly meet at swelling at 1/3 length, forming an angle of about 80 o, then nearly parallel to near each posterioventral tip and their denticle-like prolongations which diverge from body axis at about 30 o.

Larva. Genae and frontoclypeus gray except for pale area around eye. Muscle scars on head of larva, if visible, are pale and occur in a patch of about 12 scars behind eye and extending ventrally to genal suture; frontoclypeus with 3 pale muscle scars near middle of sclerite just posterior to lateral angles. Pronotum with 1-2 large, circular, pale, submarginal muscle scars at the anterior base of each leg; 2 rows of 3 pale muscle scars diverge from each other at 40 o, from middle of segment near midline; additional pale muscle scars near posterior margin of sclerite. Mesonotal and metanotal sclerites as dark as those of head and pronotum, easily differentiated from paler surrounding membranous area. Pale muscle scars on larval frontoclypeus not conspicuous in MMT, in a cluster of 3-5 as in larvae, 2 paler circular areas present transversely near middle of sclerite. Genae show additional pale muscle scars throughout area behind eye; posterioventral corner and deepest area of concavity on posterior margin are conspicuously darkened. Legs and sterna typical for genus; and sclerites on IX and X as dark as those on thoracic nota.

Emergence dates. 13 April-31 May.

Distribution. AL Calhoun, Jefferson, St. Clair (2).

Figures

Figure 25-27. Agapetus spp. male genitalia. 25) Agapetus stylifer Etnier, Baxter, and Parker. 25a, lateral view; 25b, dorsal view; 25c, ventral view, preanal appendages not shown. 26) Agapetus tomus Ross. 26a, lateral view; 26b, dorsal view; 26c, ventral view of IX and inferior appendages. 27) Agapetus tricornutus Etnier, Parker, and Baxter. 27a, lateral view; 27b, dorsal view, inferior appendages not shown; 27c, ventral view of IX and inferior appendages.