Uncicauda pirata, McLellan & Zwick, 2007

McLellan, Ian D. & Zwick, Peter, 2007, New Species Of And Keys To South American Gripopterygidae (Plecoptera), Illiesia 3 (4), pp. 20-42 : 22-24

Uncicauda pirata gen. n., sp. n.

( Figs. 1 ‐ 5 )

Material examined. Holotype ♂, paratype ♂ and ♀ CHILE, Malleco, Nahuelbuta , Los Gringos , 37°48 ʹ S; 73°01 ʹ W, 15 ‐ 17 December 1993, CMF & OSF ( USNM). Additional paratypes: 1♂, 1♀, CHILE, Malleco, Pino Hachado, 1480 m, 38°39 ʹ S; 70°58 ʹ W, 8 ‐ 9 January 1994 CMF & OSF; 2♂, Chile , Cautin, Conquillio, 1200 m, 4 ‐ 8 February 1988, L. E. Peña.

Dimensions. Male: body length 6.0 ‐ 7.0, forewing 7.5 ‐ 8.0; antenna 4.5. Female: body length 8.0; forewing 8.0 ‐ 9.0; antenna 5.0.

Adult. Small slender light brown animals. Pronotum rectangular, with angles rounded. Head a little paler along sutures, muscle attachments on head and thorax a little darker, no prominent pattern. Ocelli present. Antenna brown, long, slender, individual segments distinctly expanded apically. Palps short, brown. Row of setae runs across apex of lacinia, in front of broad terminal teeth (see Fig. 68). Legs slender, essentially brown, base of femur a little paler, especially in front leg. Front and middle tibiae paler towards apex, hind tibiae with base to subgenual organ dark brown, remainder yellowish. Tibial spurs present.

Wings ( Fig. 1 ): Venation typical of the genus except for a very short fork of Rs without crossvein. The hind wing of specimens from Los Gringos (including the holotype) has the posterior branch of M coalesced with Cu1 for a short distance. In other specimens the veins are separate but connected by a short crossvein. Veins pale brown and membrane with light brown tinge. Forewing with a darker tint around crossveins and in some specimens a purplish pigment from C to M but without speckles in cells.

Abdomen sexually dimorphic. Cerci yellowish, short, downcurved with 8 ‐ 10 segments in males and 9 ‐ 11 in females. Pilosity inconspicuous.

Male genitalia. ( Figs. 2 ‐ 4 ): Abdomen brownish or purplish, only slightly sclerotised. Each tergite with an anterior sclerite band that is medially divided on anterior tergites but entire on tergites 9 ‐ 10, although it is deeply incised from behind on segment 9. Sternites incompletely sclerotised, segments 2 ‐ 7 with widely separate narrow transverse anterior sclerites plus a continuous sclerite band across posterior third of segment; sternite 8 completely sclerotised. Subgenital plate a broadly rounded transversely oval sclerite almost truncate posteriorly. Tergite 10 well sclerotised, except for a small notch in anterior margin and a median elongate pale band in front of a sharply pointed downcurved posterior sclerite ( McLellan 1971). No epiproct. Paraprocts laterally dark brown with pale tips. The long slender sclerotised struts in side view are regularly curved and apically spatulate. Dorsoventrally the paraprocts have a narrow membranous triangular base that tapers until the sclerotised struts remain with their flat apices sometimes against each other. Penis structure not studied.

Female genitalia. ( Fig. 5 ): Abdomen pale, soft, dorsally unsclerotised except tergite 10, which is rounded apically. Sternites resemble those in males but anterior sclerites narrower and on sternite 7 posterior band shaped sclerite split into separate lateral sclerites that are slightly raised. Sternite 8 forming a sclerotised subgenital plate covering the posterior segments. Sides of subgenital plate parallel to slightly diverging posteriorly; distal margin with a broad, shallow excision. Subanal lobes triangular. The posterior sclerites on sternite 7, subgenital plate and ventrolateral face of the subanal lobes with a thick coat of stout curved colourless hairs which form a dense brush along the posterior margin of the subgenital plate.

Larva. Unknown.

Remarks. Sternite 9 of the female paratype is completely telescoped under sternite 8. The generic name describes the hooked (Latin: uncus, hook; cauda, tail) caudal end of the male and the pirate ‐ like hook of tergite 10 posterior sclerite of the male suggested the specific name.

Affinities. The new taxon is a member of Gripopteryginae in the sense of McLellan (1977). The insect has no striking autapomorphies but at the same time fits into none of the existing genera. Analysis of its affinities is hampered by lack of its larva. Therefore, generic rank as well as placement are somewhat provisional.

The known apomorphic characters of Uncicauda suggest relations with some of the smaller genera which Illies (1963) classified as Paragripopteryginae . However, all of the apomorphies in question represent reductions that may have occurred repeatedly and independently, especially shortening of the fork of Rs and of the cerci. Even loss of the male epiproct, although very unusual and known only among South American Gripopterygidae , has occurred independently. Within Gripopteryx which, by its bizarre larvae, is undoubtedly monophyletic several species have very small epiprocts, and G. serrensis Froehlich lacks it completely ( Froehlich 1993). The remaining genera without male epiproct ( Paragripopteryx , Tupiperla , Guaranyperla (all NE South American) and Potamoperla (Andean)) have a double point of male tergite 10 which is unique in the subfamily and suggests these genera represent a monophylum. We believe the new genus Uncicauda with a sharp single point of tergite 10 may be an early member or the sister taxon of this small group of genera.

Figures

Figs. 1‐5. Uncicauda pirata sp. n., adult. 1, pair of wings; 2, male abdominal tip, lateral; 3, same, ventral; 4, same, dorsal; 5, female abdominal tip, ventral. Not to scale.