Antarctoperlinae, Enderlein, 1909

McLellan, Ian D. & Zwick, Peter, 2007, New Species Of And Keys To South American Gripopterygidae (Plecoptera), Illiesia 3 (4), pp. 20-42 : 31-32

Antarctoperlinae gen. sp. III

( Figs. 30 ‐ 35 )

Material examined. 1 LA, Chile, Magal ., Penin. Cordova Ba.Borja 7. October.69 OSF ; another larva from the same locality is additionally labelled “pond”; 2 LA (partly dissected, parts on slide), Chile, Magal., I. Desolacion, Pto. Churruca , 5 October 1969, OSF .

Dimensions. Larva (final instar): body length 12.0 ‐ 13.0; antenna 6.0; cerci 1.5.

Larva. A moderately slender species, uniformly light brown and shining; the larva appears to be hairless under the dissecting microscope, except for colourless short hair fringes along the front edge of the clypeus and the rear edge of tergite 10. However, when pieces of integument are studied with a compound microscope and under transmitted light, the body is found to be covered by very fine, colourless hairs. Hairs on tergites are curved and strongly tapered towards the tip, being almost whip like on basal segments. Apices of hairs along distal segment margins are strongly curved inwards, towards the body. Floriform chloride cells on intersegmental membranes at basal abdominal segments numerous, each resembling a goblet with long basal stalk.

Head massive, simple, with distinct shallow central depression, eyes small, and ocelli indistinct. Antennae seemingly bare, with large squarish scape and narrow bell ‐ shaped pedicle; basal third of flagellum indistinctly inflated. Genae normal, simple; frons gently bulging down to the short clypeus, labrum trapezoidal, with narrow base. Sclerotised mouthparts worn, details of molar structure no longer visible, lacinial apex apparently with only a few blunt massive scoop ‐ like apical teeth. Galea longer than lacinia, with apical group of small rod shaped sensillae. Palpus simple, segment 4 a little shorter than both segments 3 and 5. Labium normal, except terminal segment of palpi wide, distinctly ovoid, fairly densely pilose.

Thorax. Pronotum a little wider than long, the anterior angles a little produced forward but barely outward. Rear angles pronounced but blunt, not produced. Meso ‐ and metanotum simple, with short wing pads. Legs short, stout, hind tarsi not reaching abdominal tip. Tibiae simple, no crests or keels. Tarsi with segment 2 short, dorsally completely divided by the basal part of distal segment.

Abdominal segments ring ‐ shaped, a little constricted just forward of the middle of each so that the segment contour appears bell ‐ shaped. Two minute dark spots on tergites 2 ‐ 9 appear to be part of the adult pattern rather than larval marks; the narrowly triangular apophyses of the antecosta of tergite 10 faintly visible by transparency. Segment 10 large, with protruding rounded posterior edge; bases of cerci and paraprocts concealed inside last segment. Cerci of about 20 segments but very short, downcurved, the apical part extremely fine, narrow and translucent. Paraprocts with sclerotised, medially partly overlapped bases from which rises a sharply pointed upcurved process; in dorsal view, the two processes appear like the forceps of an earwig (Dermaptera) while in side view the basal two thirds of their ventral edge are slightly concave to nearly straight. Gill rosette large, many fine filaments but contracted in the specimens examined.

30

Adult. Not known; however, a few traits of the developing adult were visible by transparency or were dissected out from the larvae from Isola Desolación. The wings are about 3 mm long when artificially extended in hot lactic acid. Wings were insufficiently developed to recognize details of the much reduced venation; however, Rs and M are distinctly forked, crossveins are not visible. Both mature larvae are females; a pale median strip and darker paramedian lobes that probably extend backward in the emerged adult are visible by transparency inside sternite 8. Sternite 9 contains a deeply forwardly arched darker structure.

Figures

Figs. 30‐35. Antarctoperlinae gen.sp. III, larva. 30, habitus; 31, labial segment, ventral; 32 left maxilla, ventral; 33, abdominal tip, ventral; 34, same, lateral; 35, part of abdominal tergite, with pilosity. Figs 31‐34 not to scale.