Andiperlodes tehuelche Pessacq

Pessacq, Pablo, 2009, A new Gripopterygidae (Plecoptera) species from southern Patagonia, Zootaxa 2264, pp. 51-57 : 51-55

Andiperlodes tehuelche Pessacq , sp. nov.

( Figs. 1–4 )

Diagnosis: This is the smallest species of Patagonian Gripopterygidae that lack wings. It is distinguished from other Patagonian species by an exceptionally wide pronotum in both adults and in the nymphs and by the lack of an epiproct in the males.

Male holotype. Measurements (in mm): Total length 5.4, head max. width 1.0, antennae 4.5, pronotum max. width 1.4, pronotum max. length 0.8, cerci 1.3. Stout, dark, heavily sclerotised, medium size gripopterygids, with long antennae and relatively short cerci.

Head. Dark brown, with a posterior brown band behind the eyes and labrum; covered with hair-like setae, with one longer and thicker hair-like seta at base of each antenna. Eyes small, three very small ocelli. Cephalic suture poorly visible. Antenna as long as 4.5 max. head width, covered with hair-like setae, scape and pedicel dark brown, the first the largest, second smaller, about two times first flagellar annulus length; flagellum brown, with 27–28 annuli, last ones slightly thinner and longer. Maxillae with a five-segmented palp, fifth palpomere the longest, followed in length by the third, the fourth is shortest.

Thorax. Dorsally dark brown, ventrally light brown; wide, covered with hair-like setae, more densely on its margins. Pronotum dark brown, rectangular, 1.7 times as wide as long, margins slightly concave, angles rounded. Mesonotum 2.5 times as wide as long, anterior margin concave, lateral and posterior margins convex, the latter with small triangular lateral projections pointing backwards, resembling small larval wingpads. Metanotum 2.7 times as wide as long, anterior margin straight, lateral margins convex, posterior margin concave, also with triangular lateral projections pointing backwards. Legs relatively thick, covered with short curved hair-like setae, dorsal and lateral sides with sparse, thin, straight spine-like setae between the curved ones. Apical third of femora dark brown, basal two thirds light brown; slightly expanded on the ventral margin of basal third and with a dense row of hair-like setae on it. Tibiae dark brown, with two small tibial spurs. Tarsi brown, distal tarsomere the longest, proportions about 2:1:3; tarsal claws acute.

Abdomen. Dorsally dark brown, ventrally light brown, its dorsal surface covered with hair-like setae. Terga heavily sclerotised, sterna sclerotised. Tergum X extends posteriorly, forming from dorsal view a slightly laterally expanded lobe ending in a pair of points ( Figs. 1 a, 1b). Epiproct absent. Paraprocts ( Fig. 1 b) well developed, curved upwards and surpassing segment X dorsally, apex acute, dorsal half well sclerotised, ventral half poorly sclerotised. Cerci composed of 12 segments, covered with curved hair-like setae and sparse, thin, straight spine-like setae.

Female allotype. Same as male holotype, except for: Measurements (in mm): Total length 6.4, head max. width 1.1, antennae 4, pronotum max. width 1.6, pronotum max. length 1, cerci 1.1.

Head ( Fig. 2 d): with two brown areas by the sides of the eyes. Antennae dark brown, as long as 3.6 head maximum width. Maxilla ( Fig. 2 c) with a five-segment palp, fifth palpomere the longest, followed in length by the third, fourth the shortest. Galea with several small conical projections on its apex; lacinia with one long and acute tooth on its outer apical margin, a dense row of six to eight thick and long subapical setae and six short thick setae on inner margin.

Thorax ( Fig. 2 d): Pronotum, rectangular, 1.7 times as wide as long. Mesonotum 2.2 times as wide as long. Metanotum 2.4 times as wide as long, anterior margin slightly concave, posterior margin straight. Legs: Tibiae with two tibial spurs.

Abdomen: segment X produced dorsodistally in an acute angle ( Fig. 2 b). Subgenital plate extending over ninth sternum, with two very shallow rounded lobes. Paraproct wide, pointed ( Fig. 2 a). Cerci composed of 13 segments, covered with hair-like setae and an irregular apical ring of hair-like setae.

Last instar larva. Measurements (in mm, n=10): Total length 5.94 ± 0.33, head max. width 0.98 ± 0.04, antennae 3.38 ± 0.24, pronotum max. width 1.51 ± 0.05, pronotum max. length 0.83 ± 0.05, cerci 1.55 ± 0.15. Stout, well sclerotised brown larva, with thick legs, long antennae and relatively short cerci ( Fig. 3 ).

Head: Brown, covered with minute setae and with an irregular pentagonal or octagonal cuticular pattern only visible under high magnification. Eyes small, no ocelli. Cephalic suture poorly developed. Antennae as long as 3.4 max. head width, scape and pedicel brown, the first the largest, second much smaller, about two times first flagellar annulus length; flagellum light brown, with 35–45 annuli progressively thinner and slightly longer, with an apical ring of short setae. Labrum trapezoidal, anterior margin with a very shallow middle depression and a row of minute setae, lateral margins slightly convergent anteriorly, base with several long hair-like setae on its dorsal side. Right mandible ( Fig. 4 a) with two blunt apical teeth united at their base, followed by a series of six much smaller teeth in two rows, basal to these teeth one big tooth, with a smaller one on its base; mola with a row of small, short and blunt denticles. Left mandible ( Fig. 4 b) with six teeth, four apical ones short, blunt, and broadly united on their base, two basal ones clearly differentiated and acute; mola extremely complex with four irregular rows of denticles of different length and with both acute or blunt apex. Four long hair-like setae on molar base. Maxilla ( Fig.4 c) with a five-segmented palp, fifth palpomere the longest, followed in length by the fourth, remaining ones about the same size; basal palpomere limits poorly visible. Galea tapering distally, with several short projections on its apex, several subapical short setae on its ventral side and three long hair-like setae on its inner surface; lacinia with six to ten short setae on its inner margin, a dense row of eight to ten thick and long subapical setae and several small rounded apical teeth, hidden by the setae in dorsal view. Labium ( Fig. 4 d) longer than wide, with a three-segmented palp, distal palpomere the longest, with several short hair-like setae, remaining two about the same size, with no setae; glossa with a dense bunch of hair-like setae on its apex, paraglossae with long hair-like setae, longer on its outer margin, but absent from inner margin.

Thorax: Dorsally brown, with an irregular darker pattern on disc of every notum as in Fig. 3 , ventrally light brown, wide, covered with short minute hair like setae and short rounded minute setae and with an irregular pentagonal or octagonal cuticular pattern only visible under magnification (detail in Fig. 3 ), margins with a continuous row of small spine-like setae. Pronotum 1.79 ± 0.1 times as wide as long, maximun width 1.54 ± 0.06 times head maximum width, anterior margin slightly concave, posterior and lateral margins slightly convex; angles rounded. Mesonotum 2.3 ± 0.5 times as wide as long, maximun width 1.75 ± 0.16 times head maximun width, anterior and lateral margins convex, posterior margin concave with triangular lateral projections pointing backwards resembling small wing pads. Metanotum 2.1 ± 0.3 times as wide as long, maximun width 1.5 ± 0.44 times maximum head width, anterior margin slightly concave, lateral margins convex and posterior margin concave, with a shallow projection in its center and with triangular lateral projections pointing backwards resembling small wing pads.

Legs: dorsally brown, ventrally light brown, thick. Femora ( Fig. 4 e) distinctly expanded on the ventral margin of basal third, covered with short rounded setae on its posterior margin and dorsal side and short spinelike setae on its anterior margin as in Fig. 4 e, ventro-distal angle acute; tibiae light brown covered with short setae, no tibial spurs; tarsi ( Fig. 4 f) light brown, with a ventral row of hair-like setae, sparse hair-like setae on its surface and two small spine–like setae on its apex, distal tarsomere the longest, proportions as follows: 1.5:1:5; tarsal claws acute.

Abdomen: Brown, ventrally light brown, its dorsal surface sparsely covered with short thick minute setae and scale-like pointed cuticular projections (detail in Fig. 3 ), distal margin with a row of minute setae. Sternum I very small, terga and sterna II–III separated by narrow membranous pleura; segments IV–IX forming a complete ring, segment X forms a distally oblique cylinder, produced dorsodistally in an acute lobe ( Fig. 4 g). Cerci composed of 18–22 segments, each of them progressively thinner and longer and with an apical ring of setae. Anal gills poorly developed. Paraproct well developed, with an acute tip.

Type material. Holotype male adult: ARGENTINA, Santa Cruz Province. Estancia La Angostura, nameless stream at the side of state route 29, -48.63028 latitude, - 70.61806 longitude

580 m asl. 21/II/2009, J. Muzón leg. Allotype, same data as holotype. Paratypes: 10 final instar larva, same data as holotype.

Etymology. tehuelche makes reference to the original inhabitants of the region where the species was collected.

Distribution. Southern steppe of Central Patagonia (Andean Region, Patagonian Subregion, Santa Cruz Province, Argentina)

Remarks. All specimens were collected in a small stream of about 1 m wide and 20 cm of depth, in the Patagonian Steppe.

Figures

FIGURE 1. Andiperlodes tehuelche male. 1 a, abdominal segment X, dorsal view. 1 b, abdominal segments VII – X, lateral view. Scales 1 mm.

FIGURE 2. Andiperlodes tehuelche female. 2 a, abdominal segments VII – X, ventral view. 2 b, abdominal segment X, dorsal view. 2 c, left maxilla, dorsal view. 2 d, head and thorax, dorsal view. Scales for fig. C: 0, 25 mm, for figs. a, b and d: 1 mm.

FIGURE 3. Andiperlodes tehuelche larva, habitus and detail of cuticula. Scale: 1 mm.

FIGURE 4. Andiperlodes tehuelche larva. 4 a, right mandible, ventral view. 4 b, left mandible, ventral view. 4 c, right maxilla, dorsal view. 4 d, labium, dorsal view. 4 e, femur. 4 f, tarsus. 4 g, abdominal segment X, dorsal view. Scales for figs. a – d and f: 0.25 mm, for figs. e and g: 1 mm.