Balticopteryx dui Chen, 2018

Chen, Zhi-Teng, 2018, First record of subfamily Brachypterainae (Plecoptera: Taeniopterygidae) in Baltic amber: a new genus and species, Zootaxa 4527 (4), pp. 569-574 : 570-572

Balticopteryx dui Chen , sp. nov.

Figs. 1–5 .

Adult habitus ( Figs. 1 , 2): Macropterous, wings markedly exceeding abdomen; body length ca. 6.0 mm, generally dark brown.

Head ( Figs. 1–3 ): Head rounded and dark brown, anteriorly with several scratches but without anterior ocellus or any ocellus remnant, wider than pronotum. Biocellate, each ocellus small and distant to each other; compound eyes pale in current status, not enlarged. Antennae dark and filiform, with about 50 segments. Maxillary palp threesegmented, each segment equal in length.

Thorax ( Figs. 1 , 3 ): Pronotum subquadrate, anterior margin sinuous. Coxal gills absent; sclerotized coxal extensions present instead. Legs mostly dark brown; hindlegs longest, about 1.5× longer than forelegs and midlegs; tibia with two giant ventroapical spurs; tarsus three-segmented, each segment almost equal in length; claws hooklike and sharp.

Wings ( Figs. 1 , 2, 4): Wings smoked, without any diagnostic patterns; veins dark brown. Forewing length ca. 7.0 mm; ScP reaches RA before ra-rp, apically approaching the anterior margin of forewing; only a single h vein presents in the costal area; a very pale crossvein presents in apical area; RP, M and CuA each forked with two branches; area between M and CuA with five crossveins in right forewing, and with four crossveins in left forewing; area between CuA and CuP with five crossveins in right forewing, and with seven crossveins in left forewing; AA1 simple, AA2 forked. Left hindwing length ca. 6.0 mm; ScP similar to that of forewing; RP and M each forked with two branches; crossveins r, r-m, m, and cu present; AA1 simple, basal area invisible.

Abdomen (Figs. 2, 5): Dorsal aspects invisible. Segments generally pale brown, sterna 1–7 each with a kidney-shaped dark sclerite. Sternum 8 mostly pale, lateral margins dark; posteromedial margin of sternum 8 with the opening of the oviduct, anterior margin of the genital opening darkly sclerotized and semicircular. Sternum 9 mostly sclerotized, medially with an elongated postgenital plate, which is slightly pointed distally and exceeding basal half of the paraprocts; lateral margin of postgenital plate with several hairs. Cerci composed of six segments, apical segment unmodified.

Egg ( Fig. 1 ): An isolated, dark brown and subrounded egg presents near the female and without obvious modifications, which might be the egg of this female.

Holotype. Female, a well-preserved specimen in a piece of Baltic amber from Lithuania (Eocene, ca. 40-50 Mya). The holotype is deposited in the Chen Amber Collection , Yangzhou, China, No. CZT-PLE-BA4.

Etymology. The new species is named for Professor Yu-Zhou Du from Yangzhou University, Yangzhou, China, who has contributed much to the knowledge of Chinese stoneflies.

Syninclusions. Unidentified Diptera, Coleoptera, a presumptive stonefly egg near the female adult and another two different unknown eggs.

Remarks. The shape of the presumptive egg of Balticopteryx dui is similar to another taeniopterygid, Brachyptera risi ( Morton, 1896) , the egg of which is also ovoid without conspicuous anterior and posterior poles ( Michalik et al. 2015). Eggs of family Taeniopterygidae are seldomly studied in the past and may be contribute useful information in comprehensive taxonomic identifications.

Liu et al. (2007) described two new Middle Jurassic fossil genera of Taeniopterygidae from Daohugou Village, Inner Mongolia, China. The wing venation of both genera are simple, supporting the hypothesis of Ricker & Ross (1975) that the ancient species of the family possess simpler venation than more recent species. The simple venation of the new genus described in this study also supports this hypothesis from an Eocene view.

Figures

FIGURE 1. Balticopteryx dui, gen. et sp. nov. Adult habitus, dorsal view; the presumptive egg indicated with arrow. FIGURE 2. Balticopteryx dui, gen. et sp. nov. Adult habitus, ventral view; the three tarsal segments indicated with “1st, 2nd and 3rd”.

FIGURE 3. Balticopteryx dui, gen. et sp. nov. Photograph and reconstruction of head and pronotum.

FIGURE 4. Balticopteryx dui, gen. et sp. nov. Right forewing and left hindwing, dorsal view; basal area of left hindwing not visible.

FIGURE 5. Balticopteryx dui, gen. et sp. nov. Photograph and reconstruction of terminalia, ventral view.