Siphloplecton sp. 6

Godunko, Roman J., Neumann, Christian & Staniczek, Arnold H., 2019, Revision of fossil Metretopodidae (Insecta, Ephemeroptera) in Baltic amber - Part 4: Description of two new species of Siphloplecton Clemens, 1915, with notes on the new S. jaegeri species group and with key to fossil male adults of Siphloplecton, ZooKeys 898, pp. 1-26 : 1

Siphloplecton sp. 6 Figure 14 ; Table 1

Material examined.

Male subimago in Baltic amber (Eocene), MNB, MB.I 7372, specimen originally labeled as: "6. Pseudoneuroptera III Ephemeridae "; "Museum für Naturkunde Berlin"; “Paläontologisches Museum"; "Slg.: Künow Inv. Nr.: Nr. 268-294 nur noch 9 Stück vorgefunden"; “Ephemeriden“; "Siphloplecton cf. jaegeri subim. male Nr.: 272".

Completely preserved specimen, well visible in lateral aspect. Details of head hardly visible due to resin influxes and small cracks in stone. Left forewing arcuated at half length; left hind wing twisted. Terga IX–X and, partly, genitalia covered by “Verlumung”. For measurements see Table 1 .

Description.

General colouration of body brown to dark brown. Head brown with paler antennae; eyes large, medially contiguous, uniformly brown coloured.

Thorax intensely brown; details of terga hardly visible; mesonotal suture typical for Siphloplecton ; lateroparapsidal suture not visible. Thorax ventrally hardly visible, but furcasternal protuberances of mesothorax contiguous.

Wings opaque. Forewings with several irregular dark spots (probably an artefact of fossilisation). Pterostigmatic area with 7-8 anastomosed veins. In cubital field of forewing one pair of intercalaries close to CuP (connected with CuP and CuA); one additional intercalary vein close to CuA. Hind wings with triads RS, MA and MP, 0.32 × forewing length; costal process bluntly pointed ( Fig. 14 ).

Legs typical for the genus Siphloplecton .

Abdominal segments completely preserved; terga darker than sterna.

Shape of plate poorly visible in ventral view, but generally close to the one of S. landolti (deeply incised mediocaudally, angulate, with relatively small medial projection). Shape of penis lobes hardly visible because of “Verlumung”. Visible part of penis lobes with apical sclerites rounded at tip.

Cerci partly damaged; paracercus vestigial.

Comments.

Due to the general shape of the styliger and penis lobes, and proportions of the fore/hind wings, this specimen belongs with high probability to S. landolti sp. nov. Some of the observed differences might be related to differences between subimago and imago, or may be due to the bad preservation of the genitalia. However, in order to avoid any taxonomic confusion, we refrain from attributing Siphloplecton sp. 6 to a certain species within Siphloplecton .

Figures

Figure 14. Siphloplecton sp. 6, MNB, MB. I 7372, male subimago (photograph): general lateral view, left side.