Progomphus aberrans Belle 1973
Creators: name: Molineri, Carlos
name: Rodríguez, José Sebastián
name: Leiva, Marta
name: Márquez, Javier Andrés
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Gomphidae
Progomphus
Progomphus aberrans

description: Progomphus aberrans Belle, 1973 (Figs. 1–2)
Reared material. ARGENTINA: 3 female adults with corresponding larval exuviae from Córdoba, río Salsacate, ca. San Carlos Minas, 31.18428° S, 65.10333° W, 9/Nov/2022, C. Molineri & D. Emmerich leg.
Other material. ARGENTINA: 1 male adult from Corrientes, Itá-Ibaté, arroyo Santa Lucía, 27.51318º S, 57.23370º W, 70 m, 9/Nov/2021, C. Molineri & G. Fontanarrosa leg.; 1 last larval exuvia and 1 teneral male (collected in the same patch of macrophytes) from San Luis, río Conlara, 32.894884º S, 65.513902º W, 865 m, 3/Jan/2023, J. Marquez leg.
Larva, female last instar exuvia. General coloration light yellowish with grey marks on abdomen. Head wider than long, narrower than meso- and metathorax but subequal to maximum abdominal width (Fig. 2a), cephalic lobes well developed, bulging, with abundant long, stiff setae on posterior borders, occipital margin slightly concave; genae projected and covered with setae; postclypeus and frons with abundant bristle-like setae directed backwards; interocellar area and occiput granulated. Antennae four-segmented (Fig. 2b), scape and pedicel short and globose; third segment (the longest) conical and with a concave ventral area on basal half, densely covered with bristle-like setae; fourth segment elongate and granulated, cylindrical, with rounded tip; size proportion of antennomeres: 0.16, 0.22, 1.00, 0.34. Mandibles (Fig. 1a–b) with a molar crest set in a soft, fleshy area (as usual in the genus), with the following formula: L 1 2 3 4 0 a (m 1,2,3, 4) b; R 1 2 3 4 y a (m 1,2,3,4) b; molar crest in right mandible reduced (also usual). Hypopharynx subtriangular. Galeolacinia (Fig. 1c) with four ventral teeth, the ventro-apical one the longest and three additional ones decreasing in size basally (the first, shorter one, about ½ the length of the second); the three dorsal teeth slender; palp slightly shorter than galeolacinia, triangular and curved (Fig. 1d) covered with stiff setae on lateral and ventral surfaces. Labium: Prementum—postmentum articulation reaching posterior margin of procoxae; prementum subrectangular (Fig. 1g), ratio length/maximum width 1.5, sides slightly convex, subparallel apically, with a row of thick setae; dorsal surface of prementum with scattered long setae (Fig. 1g). Ligula prominent (Fig. 1e–f), semicircular, fringed with three rows of about 20 flat rounded setae. Palp subrectangular with subtriangular distal projection 1/2 length of movable hook (Fig. 1g), inner margin smooth, outer margin bare; movable hook stout, as long as outer margin of palpal segment. Ventral surface of prementum with a submedian pair of long hair-like setae at base of ligula, and a few setae at base; dorsal surface with scattered setae. Thorax. Pronotum U-shaped, wider than long, with anterior V-shaped furrow, submedian plate slightly elevated, anterolateral corners bulging and covered with thin setae (Fig. 2a). Meso- and metathorax granulated with short setae on anterolateral corners. Wing pads strongly divergent, both wing pads almost reaching posterior margin of S4. Legs short and thick; pro- and mesotibiae without burrowing hooks and with a subbasal dorsal swelling densely covered with thick setae, pro- and mesotarsal claws cheliform, metatarsal claws long and acute with a subapical seta; pro- and mesotarsi darkened and subtriangular in transversal section. Abdomen. Slightly widening to its maximum at S4 and S5, thence gradually tapering, setose on lateral margins. Terga granulose and with short setae, with darker marks as follows: median subrectangular grey mark on S5–10, submedian oval mark on S5–10 and sublateral smaller oval mark on S7–10 (on S10 submedian and sublateral marks are fused, Fig. 2d). S2–9 with well-developed sharp posterolateral spines increasing in length rearward, those on S6–S7 subequal and longest (Fig. 1i). Dorsal median tubercles (Figs. 1h, 2d–e) small, thin and pointed on S1 to S9 (on S1 very small and thin, on S6 almost undistinguishable). Sterna covered with short setae, sternum S9 with a row of long thin setae near anterior margin; sterna S2–9 composed of three plates, S1 and S10 composed of one plate. Ventral sutures (separating the plates) blackish on S4–8. Sterna S6–9 with diffuse grey lateral markings; sternum S10 shaded with grey on central area and distal margin. Proportionate lengths of sterna S8: S9: S10 (n=3): 1.55, 1.10, 1.00. Female gonapophyses small and subtriangular (arrow in Fig. 2f). Caudal appendages pale except paraprocts with a small ventrobasal grey mark, epiproct dorsally with small anterobasal grey marks; acutely pointed and fringed with long stiff setae, epiproct and paraprocts covered with minute setae; cerci triangular. Paraprocts with the ventral inner margin strongly concave on the basal half (Fig. 2i), the concavities of both paraprocts form a ventro-basal anal hole (sensu Belle 1991).
MeasurSements (mm): Total length without caudal appendages, 21.0; abdomen without caudal appendages (ventral), 14.0; maximum width of head, 4.2; hind femur (lateral), 2.5; lateral spine on S8 (ventral, on inner margin), 0.4; epiprocts (dorsal), 2.7; paraprocts (dorsal), 2.7; cerci (dorsal), 0.85.
Larval diagnosis. Progomphus aberrans can be distinguished from the larvae of all other species in the genus by the following combination of characters: fourth antennomere relatively long and slender (Fig. 2b); mandibular formula (Figs. 1a–b) L 1 2 3 4 0 a (m 1,2,3, 4) b, R 1 2 3 4 y a (m 1,2,3,4) b; galeolacinia with 4 ventral teeth, the first (basal) one about 1/3 length of the second (Fig. 1c), palp apically pointed (Fig. 1d); prementum subrectangular (Fig. 1g), ligula without submedian tubercles, margin with three rows of flat setae, the ventral one formed by small setae, then a central row with oblong setae, and finally a dorsal row of long slender setae (Fig. 1e–f), palp with subtriangular distal projection 1/2 length of movable hook (Fig. 1g), margins smooth; movable hook slender, subequal in length to outer margin of palpal segment. Ventral surface of prementum with a submedian pair of long hair-like setae at base of ligula, and a few setae at base; dorsal surface with scattered setae; fore and mesotarsal claws cheliform; thorax and legs with whitish setae; pro- and mesotibia without distal spurs; hind tarsi darker than or concolorous with the remaining leg segments; posterolateral spines on S2–9 (Fig. 1i); small dorsal tubercles on terga S1–9 (almost undiscernible on S6) (Fig. 1h); sterna S2–9 formed by 3 plates, sterna S1 and S10 by one plate (Fig. 1i); apical abdominal segments and anal pyramid slender (Figs. 2d, 2g –i); relative length of sterna S8: S9: S10: epiproct = 1.5: 1.3: 1: 2.7.
In the male larval exuvia from San Luis, mediodorsal abdominal tubercles on S5–8 were very reduced, almost indistinguishable. The larval stage of P. aberrans share with P. kimminsi: 1) the long and slender anal pyramid with inner margin of paraproct concave on basal side, 2) the shape of the fourth (distal) antennomere (cylindrical), 3) the absence of tibial spurs, and 4) S5 with posterolateral spine. Among the Argentine species, the last three characteristics are also present in P. complicatus. Unique characteristics of the larva of P. aberrans include molar crests with 4 denticles between a and b in both mandibles (Figs. 1a–b); dorsal tubercles present on terga S1–9, but small from S5–9 (Fig. 1h); and posterolateral spines present on S2–9 (Fig. 1i).
Distribution. Argentina (Córdoba, Corrientes, Entre Ríos, Misiones; Lozano et al. 2020; San Luis new provincial record), Brazil and Paraguay (Belle 1973; Kittel & Engels 2016).
Notes. The stream where reared larvae were collected presented a channel width of 30 m, wet width of 3 m, and mean depth on 10 cm. The substrate was composed mainly by coarse sand, gravels and pebbles occupied patches on riffles. The larvae were collected in sand patches.
description: Published as part of Molineri, Carlos, Rodríguez, José Sebastián, Leiva, Marta & Márquez, Javier Andrés, 2023, Diagnoses and key for the larvae of Progomphus Selys, 1854 from Argentina (Anisoptera: Gomphidae), with first larval descriptions for P. aberrans Belle, 1973 and P. kimminsi Belle, 1973, pp. 239-259 in Zootaxa 5297 (2) on pages 240-244, DOI: 10.11646/zootaxa.5297.2.4, http://zenodo.org/record/7993190