Amphinemura denstigris, Zwick, 2010

Zwick, Peter, 2010, New Species And New Records Of Plecoptera From Korea And The Russian Far East, Illiesia 6 (9), pp. 75-97 : 77-79

Amphinemura denstigris sp. n.

( Figs. 3-8 )

Material examined. REPUBLIC OF KOREA: Holotype ♂, 6 paratype ♂, 2♀, Jirisan , Hamyang-gun, Munsu-Sa, Songjeong-li, Alt. 400 m, 35°24.74'N 127°43.82'E, 6.-27.VII. 2004, Malaise trap in forested area at sunlight; Jirisan, Hamyang-gun, MacheonMyeon, Samjeon-li, Alt. 700 m, 35°20.93'N 127°38.50'E, 27.VII.-16.VIII. 2004, Malaise trap on small stream, 3♂ paratypes, 1♀; same locality, 16.VIII.-5.IX. 2004, 1 paratype ♂.

Adult habitus. A small, pale brown Amphinemura , no pattern. FWL (= fore wing length) 6.6-7.5 mm. The pronotal surface is rough and densely covered with circular little grooves from each of which rises a tiny hair. Distinguished from congeners by the characteristic male and female genitalia.

Male. T9 with medially interrupted fringe of strong, inwardly curved setae. S9: A slender almost parallelsided tongue-shaped vesicle originates in the middle of the basal sclerite strip. Caudal part of segment divided, the middle portion forms a subparallel subgenital plate that is longer than the sides of the segment and ends in a narrow tongue-shaped extension basally delimited by some transverse folds. T10 laterally short, its middle forms a posteriorly directed sclerite plate with a heart-shaped anteromedian paler area overlain by the epiproct which originates at the caudal end of the plate ( Fig. 3 ). S10 reduced, its place occupied by the broad base of the paraprocts. Cerci simple, one-segmented, inserted dorsolaterally in a curved notch of T10. Terminal wart inconspicuous.

Paraprocts of complex shape. In ventral view ( Fig. 4 ), the triangular inner epiproct lobe with a sharply pointed straight sclerite along its medial edge is seen by the side of the subgenital plate tip. The middle lobe is membraneous and basally bare. On its outside it is connected to the outer lobe. The outer lobe is a narrow sclerite strip that bends outward at right angle at its base and is then gently curved mediad. In side view ( Fig. 5 ), the sclerite band curves dorsad and forks almost like a T. The dorsal face and the caudal end of the forked sclerite are beset with many black spines. The posterior branch of the sclerite curves down, the anterior branch is straight, in dorsal view its blunt end lies between the hairy cercus and the hairy dorsal part of the middle paraproct lobe.

In side view of the epiproct ( Fig. 6 ) the dorsal contour is regularly convex. The ventral paramedian spine-bearing sclerites are basally and apically partly concealed by the overhanging membrane of the dorsal side. The spinose section is deeply downcurved and bears around 10 short, stout black spines. The lateral sclerite of the epiproct forks in the anterior third. The dorsal branch is a delicate strip while the ventral branch is strong and forms a large hook which stands free from the rest and curves back, and mediad. In dorsal view ( Fig. 7 ) this hook is seen by transparency.

In dorsal view the epiproct ( Fig. 7 ) is pear-shaped. It narrows in a gently concave line from the wide parabolic caudal part to the gently bilobed tip which is less than half as wide as the base. A small anterior tube is largely concealed between the lobes. The surface is smooth, with a median furrow in the anterior half. The furrow is occupied by a narrow slender sclerite which anteriorly leads to a very short and inconspicuous dorsally open semi-tube. Ventral sclerites visible by transparency as dark shadows.

Female. S8 with a distinct pregenital plate bulging backward over S9. Subgenital plate on S9 flat, consisting of two transversely truncate lobes ( Fig. 8 : S) caudally separated for a short distance by a narrow well defined notch. On the sides the flat lobes of the paragenital plates ( Fig. 8 : P) project distinctly. Dark sclerotized structures inside segments 8 & 9 are visible by transparency.

Inner sclerites are best studied from the dorsal side. A wide sclerotized area is anteriorly delimited by converging uprolled edges. Between them, in front of the narrow notch in the subgenital plate lie ventrally two black, erect closely adjacent crests. Dorsally and laterally from them are two sclerites resembling narrow leaves that diverge anteriorly, like a funnel. Anterolaterally the funnel supports two anteriorly open hemispheres which in turn support a parabolic sclerite above them. Over this rises anteriorly an approximately heart-shaped shield with two slender fingers caudally and anteriorly at the top a straight sclerotized tube which leads into the membraneous spermatheca. This tube and the little tube at the tip of the male epiproct ( Fig. 7 ) are of similar diameter.

Diagnosis. Several Korean Amphinemura have rough pronota. Among them is A. steinmanni , which also has huge ventral teeth on the epiproct. However, both the T-shaped outer paraproct lobes with their caudally projecting setal fringe, and the pear-shaped epiproct of A. denstigris are distinctive and very different from A. steinmanni . The tooth-like appendage to the lower face of epiproct relates A. denstigris also to A. rai but the distinction is again easy, see below under A. rai . This small group of species may be related to Far-Eastern Amphinemura species possessing large extensions spreading laterally from the antero-ventral area of the epiproct, like A. pterygoidea Li & Yang, 2008 . In China, there are additional species with remarkable anterolateral projections from the epiproct but details of interconnections between sclerites are undescribed. The female resembles the female of A. steinmanni but the subgenital plate lobes of the latter are obliquely truncate ( Zwick 1973a: figs. 10, 11). The vaginal sclerites have some similariry with A. rai (see below), but in many species these structures are as yet undescribed.

Etymology. The freely projecting tooth-like appendage of the epiproct resembles a tiger fang, hence the name denstigris, Latin , tooth of a tiger.

Figures

Figures 3-8. Amphinemura denstigris, male abdominal tip in dorsal (3) and ventral views (4). 5, lateral view of left paraproct after removal of cercus which occupied the area labelled C; male epiproct in lateral (6) and dorsal (7) views; 8, cleared female genitalia in dorsal view; P, paragenital plate, R, receptacle, S, subgenital plate. Figs. 3-5 and 6-7, respectively, to the same scale.