Siphloplecton jaegeri Demoulin, 1968

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

publication ID	https://dx.doi.org/10.3897/zookeys.898.47118
publication LSID	lsid:zoobank.org:pub:7B407C80-9E64-4F59-95C2-B3229CF78C6B
persistent identifier	https://treatment.plazi.org/id/7FD9035A-A5F6-5731-941A-ACB9B93F19C4
treatment provided by	ZooKeys by Pensoft
scientific name	Siphloplecton jaegeri Demoulin, 1968
status

Treatment

Siphloplecton jaegeri Demoulin, 1968 Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 ; Table 1 View Table

Siphloplecton jaegeri Demoulin, 1968 - Deutsche Entomologische Zeitschrift: 252, figs 18a, c (description, designation of holotype)

Siphloplecton jaegeri Demoulin, 1968 - Staniczek and Godunko 2012, Paleodiversity : 73, figs 10a, b, 11a−c (redescription of holotype). For complete list of synonymies see Staniczek and Godunko (2012: 73).

Material examined.

Male imago in Baltic amber (Eocene), MNB, MB.I 7370, specimen labelled 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 ♂ imago Nr.: 271" ( Figs 1 A–E View Figure 1 , 2 View Figure 2 ).

Well preserved specimen, visible in dorsoventral aspect. Wings completely preserved ( Fig. 1A, B View Figure 1 ); posterior margin of left forewing and hind wings twisted. Ventral side of head and prosternum not visible, view obstructed by resin influx and cracks in stone. Foremargin and distal part of left forewing and entire left hind wing dirty brownish coloured; several dark spots on remaining part of left forewing. Such irregular pigmentation is a side effect of the specific conditions of fossilization, and must not be confused with the natural pigmentation of Siphloplecton wings (the right wings of the same specimen are colourless and translucent). Right fore- and left middle legs lost. Cerci partly damaged.

For measurements see Table 1 View Table .

Male imago in Baltic amber (Eocene), MNHN, 4655 BA ( Figs 3 View Figure 3 - 4 View Figure 4 ).

The specimen is visible in dorsoventral and, partly, lateral aspect. Head and thorax ventrally with “Verlumung”. Right fore- and hind wings fully preserved; left pair of wings partly twisted; details of cubital field not discernible. Cerci lost.

Colour yellow to yellowish-brown with darker thorax, but generally paler than all other known specimens of S. jaegeri . Wings hyaline, translucent, without any pigmentation.

For measurements see Table 1 View Table .

Description of specimens.

General colouration from pale (yellow to yellowish-brown), to dark brown (yellowish-brown to intensively brown); details of wing colouration are described above.

Head uniformly brown. Eyes large, well developed, medially contiguous ( Figs 1C View Figure 1 , 2 View Figure 2 , 3A View Figure 3 , 4A View Figure 4 ), slightly flattened laterally (MNB specimen); ocelli of MNHN specimen with slightly paler apical part and darker basally; antennae light brown, longer than head ( Fig. 3A View Figure 3 ); ocelli and antennae of MNB specimen not visible due to resin influxes ( Fig. 1 A–C View Figure 1 ).

Thorax brown with dirty maculation dorsally (MNB specimen), yellowish-brown with markedly darker sterna (MNHN specimen); mesonotal suture stretched backwards medially; lateroparapsidal suture elongated, without surrounding pigmentation; furcasternal protuberances of mesothorax fused.

Wings hyaline. Pterostigma with at least 6 anastomosed veins. Cubital field of right forewing with well-developed intercalary vein (iCu1) close to CuA and basally directly connected to it, followed by one pair of intercalaries (iCu2, iCu3) basally connected to each other and connected to CuA (in MNHN specimen also to CuP) by a short crossvein ( Figs 1D View Figure 1 , 2 View Figure 2 , 4A View Figure 4 ). Hind wings with triads RS, MA and MP ( Fig. 4A View Figure 4 ); preserved part of hind wings 0.39 × forewing length (MNB specimen). Hind wings of MNHN specimen with triads RS, MA and MP, poorly visible distally; preserved part of hind wings 0.35 × forewing length. Costal process small.

Legs brownish; tibiae and tarsi darker than femora; structure and proportions of leg segments similar to those of holotype of S. jaegeri ; outer margin of foretibia with pointed setae; measurements of leg segments in Table 1 View Table .

Abdominal segments well preserved, paler than thorax. Shape of styliger and penis lobes ( Figs 1E View Figure 1 , 3D View Figure 3 , 4B View Figure 4 ) similar to those of S. jaegeri holotype ( Demoulin 1968: 252, figs 18a, c, Staniczek and Godunko 2012: 74, fig. 11c). Styliger plate angulate, deeply incised with three prominent projections; medial projection markedly broad; basal segment of forceps basally (a) markedly narrower than adjoining apical part of plate (b) (a/b = 0.57); forceps 4-segmented; segment 2 longest, segment 4 approximately 2.47 to 2.65 times as long as wide; length ratio of segment 3 to segment 4 approximately 0.9:1. Penis lobes elongated, medially incised, triangular, with relatively inconspicuous incision between lateral and medial penis sclerites. Surface details of penis lobes not visible.

Paracercus vestigial, 5-segmented.

Comments.

Some minor differences regarding the proportions of the fore/hind wings and forceps segments between the holotype of S. jaegeri and the specimens described above are present. However, we attribute these specimens to S. jaegeri due to the presence of 1+2 intercalaries in the cubital field, pointed setae along outer margin of foretibia, and the shape of plate and penis lobes.