Leuctra georgiae Teslenko

Teslenko, Valentina A., Palatov, Dmitry M. & Semenchenko, Alexander A., 2019, Description of new apterous winter species of Leuctra (Plecoptera: Leuctridae) based morphology and DNA barcoding and further records to stonefly fauna of the Caucasus, Georgia, Zootaxa 4585 (3), pp. 546-560: 552-557

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Leuctra georgiae Teslenko

sp. n.

Leuctra georgiae Teslenko   sp. n.

( Figs. 14–24 View FIGURES 14–16 View FIGURES 17–19 View FIGURES 20–24 )


Material examined. Holotype male. Georgia. Adjaria. Kintrishi River , 16 km upstream from Kobuleti and 4 km upstream from Tchakhati Village, 41°47.192 N 41°57.390 E, 0 6.02.2017, coll. D. Palatov ( FSC EATB FEB RAS) GoogleMaps   . Paratypes: 3 males (1 male mounted), 5 females (2 females mounted), same locality and date, coll. D. Palatov ( FSC EATB FEB RAS) GoogleMaps   .

Description. Dark brown, apterous species, with tiny rudimentary wings, appearing as dark brown plates on the meso- and mesothorax; body length of males 4.0– 4.2 mm, females 5.2¯ 6.2 mm. Setation distinct, sclerotization heavy ( Figs. 14, 15 View FIGURES 14–16 ). Palpi, head, pronotum, meso- and metanotum, legs uniform black brown without pattern ( Fig. 14 View FIGURES 14–16 ). Head bears two very small lateral ocelli, poorly visible, the median ocellus indistinct, difficult to distinguish ( Fig. 14 View FIGURES 14–16 ).

The sclerite configuration on the female prothoracic and mesotoracic sterna of L. georgiae   is similar to that of L. adjariae   ( Figs. 3 View FIGURES 2–4 , 20 View FIGURES 20–24 ), except for prothoracic furcasternum as a pair of diverging bars which is larger and touching basisternum; prothoracic spinasternum of L. georgiae   is oval, and mesothoracic basisternum having a concave anterior margin ( Fig. 20 View FIGURES 20–24 ).

Male. Terga I-VII simple, heavily sclerotized, except semicircular paramedian poorly pigmented areas on posterior margins, which are increased in size to tergum VII and covered by long black setae. Tergum VIII bears anteromedial sclerotized process armed with a pair of triangular, heavily sclerotized teeth directed backward and covered by long black setae ( Fig. 16 View FIGURES 14–16 ). In lateral view teeth raised oblique upward and forward ( Fig. 15 View FIGURES 14–16 ). Tergum IX mostly unpigmented with distinct antecosta, divided medially on more than one fifth of segment width; posteromedial sclerite consists of pair pigmented triangular spots, disconnected at base ( Figs. 16 View FIGURES 14–16 , 17 View FIGURES 17–19 ). Tergum X deeply cleft, bilobed, each lobe with oblique mesal edge in dorsal view, bears a small posteromedial process, covered with tuft long black setae ( Figs 16 View FIGURES 14–16 , 17 View FIGURES 17–19 ). Between the lobes a small rounded membranous epiproct appears; a large conspicuous V-shaped pigmented sclerite is behind the epiproct ( Figs. 18, 19 View FIGURES 17–19 ). Cerci long, slim ( Figs. 16- 18 View FIGURES 14–16 View FIGURES 17–19 ), more sclerotized along inner edges than along outer ones, covered with long setae, especially along outer edges; apices round, not pigmented with vestigial terminal segment modified into an ‘eye-spot’ mark. In dorsal view cerci form a circle around styles ( Figs. 17, 18 View FIGURES 17–19 ). Paraprocts strong, styles more 2.0X shorter than specilla ( Figs. 16 View FIGURES 14–16 , 17 View FIGURES 17–19 ). Styles base wide with triangular truncate lateral edges ( Figs 16 View FIGURES 14–16 , 19 View FIGURES 17–19 ), and ending in strong sclerotized tapered to the tips, gently bent inward ( Figs 16 View FIGURES 14–16 , 17 View FIGURES 17–19 ) processes. Specilla gently tapered to the tip, apices blunt, gently bent outside in dorsal view ( Fig. 18 View FIGURES 17–19 ). Sternum IX with U-shaped unsclerotized area, ventral vesicle absent, a tiny, indistinct knob on the anteromedial margin weakly visible ( Figs. 14, 15 View FIGURES 14–16 ).

Female. Sterna with wide ventral sclerite and pair lateral membranous bands ( Fig. 21 View FIGURES 20–24 ). Sternum VIII forms a rectangular subgenital plate with two rounded posteromedial lobes ( Figs 21, 22 View FIGURES 20–24 ). In ventral view of a cleared specimen ( Fig. 22 View FIGURES 20–24 ) in ¾ of the length of the subgenital plate one notices a pair of lateral wing-shaped processes covered with black setae; each process tapered to the tip and directed to outside, makes subgenital plate slightly wider, than at anterior or posterior margin ( Fig 22 View FIGURES 20–24 ); the last third of subgenital plate bilobed, posteromedian lobes rounded with slightly concaved posteromedian margin ( Figs 21, 22 View FIGURES 20–24 ). A median less-pigmented area divides the posteriomedian lobes ( Fig. 22 View FIGURES 20–24 ). Subgenital plate fused with paragenital plate being dark brown that can be seen by transparency ( Fig. 22 View FIGURES 20–24 ). Paragenital plate with paired fan-shaped processes, directed sideward and slightly overhang from under of posterolateral corners of the subgenital plate ( Fig. 22 View FIGURES 20–24 ). Sternum IX completely sclerotized, with a produced arch-shaped extension anteromesally and pair of small triangular anretolateral unpigmented spots below subgenital plate ( Figs 21, 22 View FIGURES 20–24 ). Seminal receptacle spheroid ( Figs 23, 24 View FIGURES 20–24 ), spermathecal sclerite ring-shaped, with strongly sclerotized semi-ring which ends in a pair of small teeth; the teeth joined to each other by slightly sclerotized a central arch ( Figs 22, 24 View FIGURES 20–24 ).

Diagnosis. Apterous in both sexes. Leuctra georgiae   is distinguished from other Leuctra   species by the pair of short, triangular and heavily sclerotized anteromedial processes on male tergum VIII in combination with pair of pigmented triangular posteromedial spots on tergum IX. The male is also distinguished by tergum X deeply notched with small paired posteromedial processes, covered with long setae; epiproct small, rounded and membranous; styles shorter specilla more than 2X. The female is characterized by a rectangular subgenital plate with two lateral wing-shaped processes, posterior margin of subgenital plate with paired posteromedian rounded lobes.

Affinities. Based on tergal ornamentation of the male, L. georgiae   possibly belongs to the prima   species subgroup within the hippopus species group according to Ravizza & Vinҫon (1998) and Ravizza (2002). Within the prima   subgroup, the male of L. ligurica Aubert, 1962   has similar paired anteromedial sclerotized processes on tergum VIII. In L. ligurica   they are pointed at the apices, whereas in L. georgiae   , the apex of each anteromedial process is rectangular. The posteriomedial sclerite on tergum IX is rectangular in L. ligurica   , the same sclerite of L. georgiae   appears as a pair of pigmented triangular spots, which are disconnected at the base. The females of both species are only generally similar in rectangular shape of subgenital plates with a bilobed posterior margin. However, the female genitalia differ in detail. The spermatheca of L. georgiae   has a strongly sclerotized central arch and caudally connected arms, similar to L. ligurica   and some members of the prima   sub-group. Both species are apterous and are distributed within a relatively small area in the different mountain systems. Leuctra ligurica   is known from the western edge of the Ligurian Apennines to the eastern margin of the Ligurian Alps ( Ravizza 2002); L. georgiae   occurs on the western slopes of Meskheti Range (Lesser Caucasus) in Adjaria, Georgia.

Furthermore, the styles of L. georgiae   resemble remotely the styles of L. tarnogradski   , which are short. L. georgiae   also differs from L. tarnogradski   by the different shape of the posteromedial sclerite on tergum IX, by the lack of ventral vesicle on sternum IX, by the lack of wings, and by the very different shape of the female subgenital plate ( Zhiltzova, 2003).

Distribution. Apparently, larvae of L. georgiae   occur in the Kintrishi River, near the town of Kobulety located in Adjaria in the southwestern corner of Georgia bordered Turkey to the south and the eastern end of the Black Sea ( Fig. 25 View FIGURES 25–28 ). The Kintrishi River flows down from western slopes of Meskheti Range (Lesser Caucasus) into the Black Sea. The Kintrishi River at the type locality on altitude 180–190 m a.s.l. flows through a canyon with a width 5–6 m ( Figs. 27, 28 View FIGURES 25–28 ). Despite the river being at flood stage, the water was clear, flowing at 0.3–0.9 m /s. Adults of L. georgiae   were collected walking on the snow.

Etymology. This species is named after Georgia, where it occurs.


Fredericton Stock Culture Collection