Agapetus meridionalis 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 : 30-31

Agapetus meridionalis Etnier, Parker, and Baxter new species

Fig. 19a, 19b, 19c . Map 19

Type material. Holotype, male MMT, length 5.0 mm, EX UT 1.453 . spring run at Everett Springs Road 0.6 rd mi n of entrance to Boy Scouts of America Camp Sidney Dew, 34.5365 o N, 85.1076 o W, Floyd Co., GA, 6 April 1999, emerged 19 April, D. A. Etnier. ( NMNH)

Allotype, female MMT. Taken with holotype, emerged 19 April 1999. ( NMNH)

Paratopotypes, all EX UT 1.453 . CUAC, male pupa emerged 14 April, MMT female pupa emerged 17 April, 1 prepupa ; INHS, MMT male pupa emerged 17 April, female emerged 17 April, 1 prepupa; ROME, MMT male pupa emerged 12 April, female emerged 17 April, 1 prepupa; SCHC, male pupa emerged 14 April, 1 larva ; UMSP, male pupa emerged 6 April, 1 larva ; UT 1.453 , male emerged 14 April, female MMT pupa emerged 1 May, 4 larvae, 1 prepupa .

Diagnosis. Shares with A. crasmus , A. diacanthus , A. gelbae , A. tomus , and A. vireo the heavily sclerotized ventral and posterior portions of segment X. Differs from all of these except A. vireo in having the preanal appendage nearly circular in lateral view, with length 1.5 times depth (versus digitiform, with length 2 or more times depth), and in having the inferior appendages ovoid (versus rhomboid in A. crasmus and A. diacanthus , with posteriodorsal projection in A. gelbae , and with concave or truncate tip in A. tomus ). Posterioventral aspect of X is produced to form a denticle that angles down and back and has a very acute tip in A. meridionalis ; (posterioventral area of X is rounded and extends dorsad in A. crasmus , is bluntly pointed and extends posteriodorsad in A. diacanthus and A. gelbae , has a rounded ventral lobe in A. tomus , and forms a right angle in A. vireo ). Most similar to A. vireo (see Discussion), differing in having the posterior margin of X sloping down and back at 30 o from vertical, extending below ventral margin of X, and extending past inferior appendage; in A. vireo posterior margin of X is vertical, with its posterioventral angle not produced, not extending below the ventral margin of X, and not extending to end of inferior appendage. In addition, there are only 3 (occasionally 4) denticles on the inferior appendage in A. meridionalis (see description), while in A. vireo there is an arc of 5-10 or more denticles occupying the same area as occupied by the individual denticles in A. meridionalis .

Description. Male. Length 4.9-5.1 mm (n = 3). Male genitalia: Lateral view ( Fig. 19a ), segment IX with anterior margin thickened, straight to concave, angling down and forward at 60 o to midline, then straight to convex, angling down and back at 75 o to convex ventral margin; dorsal margin straight, slightly longer than preanal appendage, 3/4 length of ventral margin; posterior margin convex, vertical. Preanal appendage with ventral margin slightly convex to slightly concave, dorsal margin convex, tip rounded or with ventral corner bluntly pointed, length 1.5 times depth, extending 1/3 distance to end of X, with 6-8 long setae dorsally. Sides of X sclerotized throughout, more heavily so along ventral and posterior margins; dorsal base of X slightly up-sloped. Posterior margin of X projected down and back at 30 o from vertical, its dorsal continuation a sharp, protruding, vertical denticle; posterioventrally, X is produced down and back below the ventral margin of X, its sharply pointed tip extending past tip of inferior appendage. Membranous area between lateral plates of X protruding slightly above its concave dorsal margin. Inferior appendages ovoid, length = 2.2 times depth, posteriodorsal portion extending farther rearward than posterioventral portion, tip rounded, ventral and dorsal margins slightly convex; denticles on inner surface visible as darkened areas near ventral margin at mid-length, and submarginally at posteriodorsal “corner”; a smaller, submarginal denticle near middle of posterior margin occasionally visible.

Dorsal view ( Fig. 19b ). Anterior margin of IX with broad, deep, U-shaped emargination; posterior margin concave between lateral margins of X and preanal appendages, straight, faint, transverse suture between IX and X; longitudinal ridge on midline of IX. Dorsal inner margins of lateral sclerotized areas of X with V-shaped junction near base of segment, outer margins slightly divergent to end of segment, area between sides of X membranous. Posterioventral angle of X with long, sharply pointed projection directed posteriolaterad at 30-45 o from body axis; posteriodorsal denticle of X nearly erect, at about same angle as posterioventral denticle, sharply pointed. Subterminal dorsal denticle of inferior appendage (not shown) nearly transverse, angled slightly posteriad.

Ventral view ( Fig. 19c ). Anterior margin of IX barely concave; its posterior margin forming an obtuse (100-120 o) angle between bases of inferior appendages; depigmented area on posterior 1/3 of segment bounded anteriad by transverse row of setae. Inferior appendages angular, in contact at base, inner margins convex, diverging from each other at 30-50 o to base of marginal denticle at mid-length, then more divergent and concave to second denticle at 3/4 length of appendage, these denticles connected by a nearly continuous, darkened ridge; subterminal, distal denticle about same size as other two, with a much smaller denticle occasionally apparent about midway between distal two denticles; outer margin of appendages convex and slightly divergent. Ventral arms of X (not shown) converge from base to mid-length where they nearly or actually meet, and then diverge in a smooth curve to tips.

Larva. Head uniformly dark brown except for oval pale area around eye, darker than other sclerites. Pale muscle scars visible on shed sclerites of MMT in 3-4 rows behind eye, and in 2 rows of 2 on middle of posterior 1/2 of frontoclypeus. Pronotum uniform tan, pale muscle scars in a row from middle of posterior margin to middle of mesal margin, and scattered near anteriolateral margin, on each sclerite. Muscle scars not apparent on intact larvae. Meso- and metanotal sclerites tan, darker than adjacent membranes, and easily visible. Legs amber. Prosternal sclerite with median side about 2/3 length of outer side. Mesosternal sclerites mostly black except for pale streak along midline. Legs, sterna, and sclerites on IX and X otherwise typical for genus.

Emergence dates. 6 April-1 May.

Distribution. GA, known only from the type locality.

Discussion. There is a possibility that this species is not valid, and represents a variant population of A. vireo . We choose to treat it as a valid species at this time because of its potentially precarious status and to stimulate additional research. See discussion under A. vireo for additional aspects of our rationale.

Etymology. meridionalis = of the south, in reference to its southerly distribution.

Figures

Figure 19-21. Agapetus spp. male genitalia. 19) Agapetus meridionalis Etnier, Parker, and Baxter. 19a, lateral view; 19b, dorsal view, inferior appendages not shown; 19c, ventral view of IX and inferior appendages. 20) Agapetus minutus Sibley. 20a, lateral view; 20b, dorsal view; 20c, ventral view of IX and inferior appendages. 21) Agapetus pegram Etnier, Baxter and Parker. 21a, lateral view; 21b, dorsal view; inferior appendages not shown; 21c, ventral view of IX and inferior appendages.