Amphinemura baei Ham and Lee, 1999

Zwick, Peter & Baumann, Richard W., 2011, Nemoura Jejudoensis A New Species Of Stonefly And The Redescription Of Amphinemura Baei Ham And Lee (Plecoptera, Nemouridae) From Jeju Island, Korea, Illiesia 7 (15), pp. 148-155 : 151-154

Amphinemura baei Ham and Lee

( Figs. 7-18 )

Amphinemura baei Ham and Lee 1999:120 .

Holotype male; Donneko , Sugyipo-si [Seogwipo City], Jeju-do, Korea.

Material studied. Republic of Korea, Cheju Island , Sogwipo City [Seogwipo City], spring above KAL Hotel fish hatchery, 10 November 1986, M.F. Whiting, 18 ♂, 9 ♀ , plus 4♂, 4 ♀ for SEM study; Sogwipo City , Tonneko spring [Seogwipo City, Donneko], 18-XII 1986, M.F. Whiting, 1♂ ; Chungmoon City , Chonyeon waterfalls [Seogwipo City, Jungmun, Cheonjeyeon falls], 28 September 1986, M.F. Whiting, 2♂, 1♀ ; 5 Dec. 1986, M.F. Whiting, 2♂, 2♀.

Size and habitus. Front wing length 5.8-6.8 (mean 6.4) mm in ♂, 6.6-8.2 (mean 7.8) mm in ♀. Habitus as typical of genus. Pronotum with very dense coarse punctation, rough, matt. Body brown, legs and antennae brown with indistinctly paler bases, palpi yellowish. Wing veins brown, membrane with brownish tint.

Male. T9 medially constricted, caudal margin on either side of constriction curved, with a few rough setae ( Fig. 11 ). A rhomboid membranous pale area remains between T9 and the also constricted T10 which is medially only a narrow strip in front of the epiproct base plate ( Fig. 12 ). Base plate under the epiproct largely membranous.

Epiproct in dorsal view parallel-sided, anterior third enlarged in gentle curve which turns abruptly mediad ( Fig. 7 ). Basolaterally, the bases of the ventral sclerites project a little beyond the general contour. Dorsum densely covered with fine spicules, surface divided by fine suture which anteriorly forms a deep cleft separating two short membranous lobes. Between these projects, a dorsally split, anteriorly bifid tube. Laterally from it the spinose dark apices of the lateral sclerites project ( Fig. 13 ). From beneath, the apices appear as black spinose humps ( Figs. 14, 16 ). In ventral view ( Fig. 8 ), the sclerites converge and narrow anteriorly until they lie close together, leaving only a narrow space between them. In it occur some spines of which mainly the insertion rings are seen from beneath. The spines themselves are best seen in lateral view. In side view the epiproct is strongly curved, dorsal surface without projections.

S9 with a long and slender vesicle, slightly enlarged above base, center of caudal half membranous ( Fig. 18 ). Caudal margin of S9 forming a triangular subgenital plate, that carries the apical gonopore.

Paraprocts complex. Sclerite of outer lobe straight, then bent forward at right angle, the anterior part joined to apical part of middle sclerite but junction concealed behind the simple cercus. The middle sclerite is a slender sinuous band ending in a forward directed sclerite, with an apical row of long spines forming a concave line. It surrounds the pilose apex of the large membranous lobe situated above the short triangular inner sclerite ( Figs. 15, 17 ).

Female ( Fig. 9 ). S8 with distinct pregenital plate. S9 largely covered by sclerotized anteriorly bare subgenital plates (sg) separated by a short narrow median slot. Caudal parts drawn out into triangular lobes appearing a bit swallow-tailed, mediocaudal edge gently sinuous. A caudolateral notch exposes a rounded pilose paragenital plate (pg).

In cleared slide-mounted female genitalia in dorsal view ( Fig. 10 ), the paragenital plates form the dorsal most layer in the form of a transparent triangle on each side. Below it are located the much larger dark triangular extensions of the subgenital plates which carry an acute, apparently hollow process (ap) along the medial edge, near midlength. There is a transverse crest (tc) on each sclerite. Anteriorly each sclerite supports an oval sclerotized internally rough pocket (rp). Between the latter is a funnel (f) formed by a sclerotized cone with a well defined straight median tube leading into the base of the membranous receptacles.

Diagnosis. A member of the Amphinemura luteipes - group ( Aubert 1967) which is, among other things, distinguished by the tube projecting from the epiproct apex. Most species have a roughly punctate matt pronotum, females of most have a distinct pregenital plate and neatly separate truncate lobes of the subgenital plate. The group is widespread in Asia and includes several Korean species ( Zwick 2010).

The present male is readily distinguished by the strong curvature of the row of spines on the paraproct tip, and by its epiproct. Presence of a strong apical sclerite on the lateral epiproct sclerites suggests close relations with A. steinmanni Zwick , A. denstigris Zwick , and A. rai Ham and Lee. However , in these species the apical sclerite is long and toothshaped.

Females of the same species are similar, not all can be reliably identified by external characters. The distinctive inner vaginal structures are known only in a few. Among these, A. denstigris and A. rai also possess apical funnels that during copula may perhaps receive the apical epiproct tube. Females of this species are mainly distinguished by the exceptional length of the funnel, the acute hollow process, and the transverse crest.

We know of no closely similar species from China or Japan.

Figures

Figs. 7-10. Amphinemura baei. 7. Male epiproct in dorsal view. 8. Same, ventral view; 9. Female genitalia, ventral view. 10. Vaginal complex, cleared specimen in dorsal view; ap, acute process; f, funnel; pg, paragenital plate; rp, rough pocket; sg, subgenital plate; tc, transverse crest.

Figs. 11-18. Amphinemura baei. 11. Male terminalia, dorsal, anterior. 12. Male terminalia, dorsal, posterior. 13. Epiproct, lateral. 14. Epiproct, apex, lateral. 15. Right paraproct, dorsal. 16. Epiproct, apex, terminal. 17. Subgenital plate, apex and right paraproct, ventral (cercus removed). 18. Subgenital plate, base, showing vesicle.