Apobaetis etowah ( Traver 1935 ), 2004

Cruz, Paulo Vilela, 2020, Redescription of three species of Apobaetis Day, 1955 (Ephemeroptera: Baetidae), Zootaxa 4808 (2), pp. 317-330 : 318-322

Apobaetis etowah ( Traver 1935)

Apobaetis indeprensus Day 1955 (syn.)

Pseudocloeon etowah Traver 1935 (orig.)

Diagnosis. Male imago. 1) posterior margin of styliger plate triangular, area between unistyligers without emargination (Fig. 13 in Day 1955).

Larva. 1) labrum rectangular, distal margin without shallow medial emargination, dorsal surface with three to four short and blunt setae medially near distal margin ( Fig. 2A ); 2) lingua subquadrangular, with one medial protuberance ( Fig. 2D ); 3) maxillary palp long, 1.6× length of galea-lacinia, apex of segment II with constriction ( Fig. 2E ); 4) labial palp segment II with pointed and apically directed distomedial projection, segment III rectangular, distal margin deeply concave ( Fig. 2F ); 5) tarsal claws 0.85× length of tarsus, without row of denticles ( Fig. 3A ); 6) posterior margin of terga IV with triangular, pointed spines ( Fig. 3C ).

Redescription. Larva. Head: antenna with minute spines and fine, simple setae on apex of each segment. Frons with two keels. Labrum ( Fig. 2A ): rectangular, broader than long; length about 0.6× maximum width; distal margin without shallow medial emargination; ventral surface with robust spine-like setae on distolateral and distal margin; dorsal surface with three to four short and blunt setae medially near distal margin; dorsal surface with one row of long and thin setae medially, near distal margin. Right mandible ( Fig. 2B ): incisors deeply cleft in two sets; outer and inner set of incisors with 3 and 2–3 denticles, respectively; prostheca slender, bifurcated at apex; margin between prostheca and mola concave; tuft of spine-like setae at base of mola absent; denticles of mola not constricted; lateral margin convex. Left mandible ( Fig. 2C ): incisors deeply cleft in two sets; outer and inner set of incisors with 5 and 3 denticles, respectively; prostheca robust, bifid at middle, inner lobe slender, outer lobe robust; margin between prostheca and mola concave; tuft of spine-like setae at base of mola absent; subtriangular process wide; denticles of mola not constricted; lateral margin convex. Hypopharynx ( Fig. 2D ): lingua subquadrangular, with one medial protuberance, and short apical tuft of setae, subequal than superlingua; superlingua not expanded, with short, fine, simple setae scattered over distal margin. Maxilla ( Fig. 2E ): maxillary palp long, 1.6× length of galea-lacinia; apex of segment II with constriction, similar to a third segment; maxillary palp with fine and simple setae scattered over surface. Labium ( Fig. 2F ): glossa broad basally, narrowing slightly apically, subequal in length to paraglossa; inner margin with one row of blunt setae; apex with three short spine-like setae; outer margin with six spine-like setae; ventral surface covered with thin setae. Paraglossa curved inward; apex with two spine-like setae; outer margin with one row of ten robust spine-like setae; dorsal surface with one longitudinal row of seven robust spine-like setae near inner margin; ventral surface with one longitudinal row of five robust spine-like setae at middle. Labial palp with segment I 0.8× length of segments II and III combined; segment I covered with micropores (not illustrated); segment II with pointed and apically directed distomedial projection, apex of distomedial projection slightly concave, outer margin and distomedial projection covered with fine, long and simple setae; inner margin bare; segment III rectangular, length 0.5× width, covered with fine, long and simple setae on outer margin, ventral surface with five robust spine-like setae near outer margin, distal margin with one row of six robust spinelike setae, distal margin deeply concave.

Thorax. Foreleg. Femur ( Fig. 3A ): dorsally with row of 12 short concave and blunt setae (similar with Fig. 5C in Cruz et al. 2018); apex with two concave and blunt setae; ventrally with row of elongated spine-like setae. Tibia. Dorsally bare; ventrally with one row of nine short spine-like setae. Patella-tibial suture present, apparently restricted to ventral margin ( Fig. 3B ). Tarsus: bare dorsally; ventrally with one row of nine short spine-like setae. Tarsal claws 0.8× length of tarsus, row of denticles absent. Abdomen: terga surface covered with scale-like triangular spines, micropores and short, fine and simple setae (not illustrated); posterior margin with triangular, pointed spines ( Fig. 3C ). Gills as in Figure 1 in Day (1955). Paraproct ( Fig. 3D ) with marginal spines, posterolateral extension with spines. Cerci with small lateral spines on all segments, paracercus without spines.

Material examined: Paratype of A. indeprensus , larva, USA, California, Tuolumne River, Stanislaus County, near Modesto , 14/viii/1954, H.L. Day, PERC .

Figures

FIGURE 1. Dorsal habitus. A. Apobaetis fiuzai holotype; B. Apobaetis fiuzai, abdominal details of a paratype; C. Apobaetis signifer holotype; D. Apobaetis signifer, abdominal detail of the holotype.

FIGURE 2. Apobaetis etowah. A. labrum (left d.v., right v.v.); B. right mandible; C. left mandible; D. hypopharynx; E. maxilla; F. labium (left d.v., right v.v.).

FIGURE 3. Apobaetis etowah. A. foreleg; B. detail patella-tibial suture, red arrow indicates the location of suture; C. posterior margin of tergum IV; D. paraproct.

FIGURE 5. Apobaetis fiuzai. A. foreleg; B. posterior margin of tergum IV; C. paraproct.