Progomphus lambertoi Novelo-Gutiérrez

Novelo-Gutiérrez, Rodolfo & Gómez-Anaya, José Antonio, 2011, The larva of Progomphus lambertoi Novelo-Gutiérrez, 2007 (Odonata: Gomphidae), Zootaxa 2872, pp. 58-62 : 58-62

Progomphus lambertoi Novelo-Gutiérrez

Figs. 1–9

Material. Four exuviae (3 ɗ, reared, 1 Ψ), 17 F0 larvae (9 ɗ, 8 Ψ). MEXICO: Michoacán; Municipality of Aguililla, Aguililla, stream Τanque verđe (IO2O m), I8 43 •5O3 N﹔ IO2 47•687 W, 2O­II­2OO5, 7 larvae (2 ɗ emerged on I8­Iv­2 OO5)﹔ Μunicipality οf Τepalcatepec, Ríο Pinοlapa (6 I 6 m), I9 OO•524 N﹔ IO3 OI•456 W, 28­III­2 OO5, I ɗ emerging in field (13 h), 1 exuviae (Ψ)﹔ Μunicipality οf Cοalcοmān, La Chichihua (II3 O m), I8 44 •8 I2 N﹔ IO3 I3 •379 W, O 2­Iv­ 2OO5, II larvae﹔ Μunicipality οf Apatzingān, Califοrnia (28O m), I9 O6•2O7 N﹔ IO2 27•786 W, I larva, all R. Novelo, J.A. Gómez leg. Deposited at Colección Entomológica del Instituto de Ecología, A.C., Xalapa ( IEXA).

Description. Exuviae yellow, larvae reddish-yellow; mature larvae large in size (≥ 25 mm), body enlarged and tapering caudad, most of the dorsal abdominal protuberances vestigial or reduced.

Head. Wider than long, narrower than thorax and abdomen (Fig. 1), cephalic lobes well developed, bulging, with abundant long, stiff setae on posterior borders, occipital margin straight. Labrum bare, its anterior border fringed with long, stiff setae and with a hump-like protuberance immediately behind that. Anteclypeus bare; postclypeus and frons with abundant bristle-like setae directed backwards; interocellar area and occiput granulose. Antennae four-segmented (Fig. 2), scape and pedicel short and globose, third segment the longest, moderately flattened dorso-ventrally, densely covered with bristle-like setae on dorsal surface, fourth segment elongate, cylindrical, with rounded tip and mostly bare; size proportion of antennomeres: 0.24, 0.20, 1.0, 0.44. Mandibles (Fig. 3) with a molar crest set in a soft, fleshy area, with the following formula (sensu Watson 1956): L 1 2 3 4 0 a (m 1,2,3,4) b; R 1 2 3 4 y a (m 1,2,3) b; molar crest in right mandible greatly reduced. Ventral pad of hypopharynx subtriangular, longer than wide (Fig. 4), densely covered with long, stiff setae on lateral surfaces and ventral border. Maxilla: Galeolacinia (Fig. 5) with seven teeth, the apical one the longest and stoutest, the three ventral teeth short, robust, and moderately incurved, the three dorsal teeth long, robust, and slightly incurved at tip; palp short and thick, incurved, ending in a robust spine, with numerous long, stiff setae along its external margin. Labium: Prementum-postmentum articulation scarcely reaching posterior margin of procoxae; prementum subrectangular (Fig. 6), 0.20 longer than its widest part, sides straight and slightly divergent apically, with a row of hair-like setae; dorsal surface of prementum with setae as follows (Fig. 6): 3–5 basidorsal and 3–4 mid-lateral stiff setae, a group of short hair-like setae close to the base of each palp, and long, delicate, sparse setae on each side of midline without a particular arrangement. Ligula prominent (Fig. 6), widely convex, its dorsal surface covered with very minute scale-like setae, its distal border fringed with a dense row of flabellate scale-like setae whose bases are overlaid by another row of shorter, semicylindrical, scale-like setae. Palp short and thick (Fig. 6), end hook stout and slightly incurved, bluntly pointed, internal margin smooth, external margin bare; movable hook shorter than palpal lobe, blunt at apex. Ventral surface of prementum with a very long, delicate seta at base of ligula, one on each side of midline.

Thorax. Pronotum subrectangular, wider than long, lateral margins straight and parallel, postero-lateral corners widely rounded, mostly granulose except for two large, oval, bare areas, one on each side of midline (Fig. 1). Pterothorax granulose, bare on sutures. Wing pads strongly divergent, anterior wing pads reaching posterior margin of S4, posterior ones reaching basal 0.25 of S5. Legs short and thick, strongly pubescent; pro- and mesotibiae without burrowing hooks, pro- and mesotarsal claws cheliform, metatarsal claws long and acute; all claws with pulvilliform empodium.

Abdomen. Enlarged, slightly widening to its maximum at S5, thence gradually tapering, heavily setose on lateral margins. Tergites granulose-setose, with a complex mottled pattern, posterior margins with a row of spiniform setae which increase in size and robustness rearward (Fig. 1). S4-9 with well developed sharp lateral spines increasing in length to rearward, those on S8 the longest; sometimes a reduced or minute spine present on S3 on one or both sides. Dorsal protuberances (Fig. 7) highest on S1 and S2, then diminishing in size on S3-S5, vestigial on S6, then slightly and gradually increasing on S7-S9, those on S4-S9 quite low. Sternites granulose-setose, yellow on S1-5, yellow with reddish-brown markings on S6-8, color pattern of S9-10 as shown in Fig. 8a; sternite 9 with a subbasal, transverse fringe of long, stiff setae most of which reach posterior margin of sternite; sternites 1–8 composed of three plates, 9 and10 composed of one plate; proportionate lengths of sternites 8–10: 0.9, 0.9, 1.0. Male gonapophyses absent. Female gonapophyses rudimentary, mostly hidden on posterior margin of sternite 8, widely divergent with rounded apex (Fig. 8b). Caudal appendages acutely pointed, heavily setose; basal 0.40 of epiproct and paraprocts granulose, reddish-brown, apical 0.60 with some spiniform setae and hair-like setae, reddish-yellow; male epiproct tubercles at basal 0.34; cerci triangular, dark brown on basal 0.60, yellowish on apical 0.40 (Fig. 1); size proportion of caudal appendages: cerci 0.44, epiproct 1.0, paraprocts 1.0; epiproct and paraprocts as long as sternite 10.

Measurements (in mm) [those of exuviae in square brackets] (x= mean): Total length including caudal app. 26– 29.7, x= 27.8 [27.3–29.3, x= 28.3]; abdomen (ventral) 16–20.4, x= 18.8 [18.3–19.5, x= 18.9]; maximum width of head 4.9–5.3, x= 5.1 [5–5.2, x= 5.1]; hind femur (lateral) 3.4–3.7, x= 3.5 [3.5–3.6, x= 3.56]; lateral spine on S8 (ventral on inner margin) 0.4–0.6, x= 0.6 [0.5–0.6, x= 0.53]; epiproct and paraprocts (dorsal) 2–2.3, x= 2.16 [2–2.1, x= 2.03].

PLATE I. Figs. 1–3. Details of the larval morphology of Progomphus lambertoi . 1) Habitus of the last stadium larva; 2) Right antenna, lateral view (I–IV, antennomeres; m, membrane) (setae omitted); 3) Mandibles: a and c, right mandible, b and d, left mandible; a and b dorso-ental view, c and d ventro-ental view.

PLATE II. Figs. 4–8. Details of the larval morphology of Progomphus lambertoi . 4) Hypopharynx, ventral view; 5) Right galeolacinia, ventral view; 6) Prementum, dorsal view; 7) Abdomen, left profile; 8) a: sternites (st) 9–10 and caudal appendages (pp, paraprocts; ep, epiproct); b: female gonapophyses; 9) S6–8 of the larva of Progomphus borealis , dorsal view (modified from Belle 1991).

Remarks. Larvae of Progomphus lambertoi were found in open rocky streams of third and fourth order, at shallow places with moderate water flow, in a substrate composed mainly of sand, some rough gravel, a few cobbles and occasionally fragmented detritus. One male was caught at the moment of emergence, which occurred in horizontal position on a dense mat of filamentous algae, in an exposed sunny spot, on March 28, 2005 at 13 h. The other two males emerged in the field on small rocks, at 16 h on April 18, 2005.