Aphylla protracta (Hagen)

Novelo-Gutiérrez, Rodolfo, 2014, The larva of Aphylla protracta (Hagen, 1859), and a redescription of the larva of A. angustifolia Garrison, 1986 (Odonata: Gomphidae), Zootaxa 3884 (4), pp. 387-393 : 388-391

Aphylla protracta (Hagen)

(Figs. 1–6, 7a,c, 8a, 9a, 10)

Material. Fifteen exuviae (9♂, 6♀, one ♂ reared), 7 F-0 larvae (3♂, 4♀). MEXICO: Michoacán; Municipality of Coahuayana, arroyo El Ticuiz (18° 40.403 N; 103° 40.601 W, elevation 10m asl, stream in highly disturbed tropical forest), 29 March 2005 (1♀), 0 1 June 2005, (2♂, one reared and emerged on 0 3 June 2005, 14 exuviae), 28 September 2005 (3♀), 20 January 2006 (1♂), 10 July 2006 (1♂), all J.A. Gómez, R. Novelo leg. All specimens deposited in Colección Entomológica del Instituto de Ecología, A.C., Xalapa ( IEXA).

Description. Large larva (36.8–43.4 mm total length), body robust, setose on legs and sides of abdomen, strongly tapering caudad with abdominal segment 10 extremely elongated, coloration yellow (Fig. 1) to light yellow-brown, exuviae brown.

FIGURE. 1. Last stadium larva of Aphylla protracta . a) dorsal view, b) ventral view.

Head: Wider than long, but narrower than thorax and abdomen. Labrum 0.9 mm long, mostly bare, anterior border with dense brush of golden setae, flattened ventrally; clypeus, frons and vertex bare, a tuft of long, upturned, golden setae on frontolateral margins of frons (between antenna and the anterior margin of compound eye), occiput mostly bare, with long, golden setae on occipital lobes, anterior margin of frons slightly concave. Antennae 4- segmented (Fig. 2), densely covered with long, whitish setae on lateral margins, scape globose, pedicel subglobose, 3rd antennomere largest, subcylindrical, flattened on ventral surface, 4.2 times longer than its widest part, 4th antennomere reduced, digitiform, upturned; scape, pedicel and 3rd antennomere yellow, 4th antennomere brown, size proportions: 0.30, 0.22, 1.0, 0.12. Compound eyes moderately developed; ocelli creamy pale. Occipital lobes rounded, bulging. Mandibles (Fig. 3) with molar crest, formula: L 1234 0 a(m1-4)b / R 1234 y a(m1-2 or 1-3)b, in both FIGURES. 2–5. Details of the morphology of the larva of A. protracta . 2) Left antenna, dorsal view (setae omitted); 3) Mandibles: a and c, right mandible, b and d, left mandible (a and b, ventroexternal view, c and d, internal view); 4) Right maxilla showing palp and galeolacinia, ventral view; 5) Ventral pad of hypopharynx.

mandibles tooth a>b, tooth y in right mandible large, almost as large as incisors 2 and 3 (Fig. 3a). Maxillae: Galeolacinia (Fig. 4) with 7 moderately incurved teeth, three dorsal teeth more or less of same length and robustness, four ventral teeth of different size, apical one largest; maxillary palp thick and robust. Ventral pad of hypopharynx approximately diamond-shaped, withish, soft, with long, hirsute, stiff setae mainly toward rounded apex (Fig. 5). Labium: Prementum-postmentum articulation reaching posterior margin of procoxae. Prementum (Figs. 1b, 6) yellow, 0.25 longer than its widest part, lateral margins smooth, straight at apical 0.60, slightly concave on basal 0.40 (Fig. 6a); a longitudinal, bare, central sulcus on basal 0.70 of ventral surface, ending distally in a large, shallow, concavity just below ligula; ligula very poorly developed (Fig. 6a), apical margin slightly convex, with a double row of short, stout piliform setae (Fig. 6b); labial palp stout (Figs. 6b and c), yellow, with some sparse long, white, delicate setae on ventral and external surfaces, apical lobe reddish, sharp, stout, strongly incurved, internal margin with 3–4 robust, conical teeth, very basal part of this margin with a finely serrate border; movable hook yellowish-red, almost as long as palp, sharp and moderately incurved.

FIGURES. 6–7. Details of the morphology of Aphylla spp. larvae. 6) Prementum: a, ventral view; b, ligula and palps, dorsal view; c, right palpus, ventral view. 7) Abdomen: a and b, left lateral view of segments 1–9 showing the profile of the dorsal protuberances; c and d, dorsal view of tergites 6-9 showing the reduced or absent dorsal protuberances (Figs. 6, 7a and c, A. protracta ; Figs. 7b and d, A. angustifolia ).

Thorax: Prothorax slightly narrower than head, setose on inferior border. Anterior margin of pronotum slightly concave, lateral margins convex, posterior margin sinuate. Synthorax mostly bare, with some tufts of long, curled setae on inferior margins, meso- and metaspiracles evident. Legs very short (e.g.: when fully extended, hind legs scarcely reaching anterior margin of abdominal segment 6), strongly setose, with long, whitish, delicate setae mainly on sides, and shorter, stiff, yellow setae mainly on anterior surfaces of pro- and mesotibiae and on external surfaces of pro- and mesotarsi; burrowing hooks moderately developed (Fig. 1); femora and tibiae of hind legs of the same length; claws simple, without a pulvilliform empodium. Anterior wing pads slightly divergent, posterior wing pads parallel, with abundant, delicate setae on margins and minute setae along primordial veins, remainder of surface mostly bare; anterior and posterior wing pads reaching basal half and posterior margin of abdominal segment 4, respectively.

Abdomen: Yellow, enlarged, tapering caudad (Fig. 1a), ventral surface more or less flat (Fig. 1b), dorsal surface convex, with dorsal protuberances (Fig. 7) well developed on S2-4, reduced on S5, vestigial or absent on S6–9, lacking on S10, all of them covered with abundant, small, stiff, reddish setae, those on S2–3 erect, vertical Fig. 7a); lateral spines lacking entirely; tergites 2–4 with combined short and long, delicate setae, tergites 5–8 with minute reddish setae, mainly on middle third of posterior margins, tergite 9 with abundant small, reddish setae on most of its surface and entire posterior margin; lateral margins of S2–9 and entire surface of S10 densely setose; tergites 2–8 with a sublateral, mound-like protuberance on each side of midline, at midlength of each tergite; S10 cylindrical (Fig. 1), reddish-brown, very long, five times longer than its base, much longer than S6+7+8+9. Sternites 1–9 light yellow (Fig. 1b), sternite 10 reddish-yellow; sternites 1–7 and 9 divided into three plates, sternite 8 divided in five plates (Fig. 8a), ventral sutures parallel on 2–8, slightly divergent caudally on 9; sternites 2–8 with three transversal, subbasal swellings (lumps), one in the midline, other two to each side of central one. Male gonapophyses lacking; female gonapophyses reduced, trapezoid, widely truncate at apex, internal margins widely divergent, V-shaped, almost twice wider than long (Fig. 9a). Caudal appendages (Fig. 10) very short, pyramidal, covered with abundant, small, stiff setae, cerci reddish-brown, sharply-pointed, epiproct and paraprocts mostly creamy pale, epiproct wide at base and strongly narrowed at apical half, as long as cerci but slightly shorter than paraprocts.

Measurements (range followed by mean). Last instar larvae (N= 7); Total length (TL) (incl. caudal app.) 36.8–43.4, 40.1; abdomen (Ab) (ventral, excl. caudal app.) 25.6–32, 28.6; maximum width of head 5.3–5.5, 5.4; hind femur (Hf) (lateral) 4.3–4.5, 4.4; segment 10 (S10) (ventral, excl. caudal app.) 9.3–11.2, 10.2; epiproct (Ep) 0.9, cerci (Ce) 0.9, paraprocts (Pp) 0.9–1.0, 0.98. Exuviae (N= 15): TL 39.7–45.2, 43.2; Ab 29.5–33.7, 32.2; Hf 4.2–4.7, 4.4; S10 9.5–12, 11.0; Ep 0.8–0.9, 0.87, Pp 0.8–1.0, 0.95, Ce 0.8–0.9, 0.87.

Habitat. Larvae of this species were found in both lotic and lentic water bodies, at muddy edges of sluggish streams with abundant grasses and patches of Eichhornia crassipes (Mart.) , and at the shoreline of lagoons.