Germanostenolestes lutzi, Nel, André & Fleck, Gunther, 2012

Nel, André & Fleck, Gunther, 2012, A new genus and species of Sieblosiidae from the Middle Miocene of Germany (Odonata: Epiproctophora), Zootaxa 3582, pp. 64-68 : 65-67

Germanostenolestes lutzi sp. nov.

Figures 1–3

Material. Holotype NHM OR 59573, Van Breda Collection, May 1871, NHMUK, London, UK. Etymology. Named after our colleague Dr H. Lutz.

Age and outcrop. 13.6-14.8 Ma, Middle Miocene, Öhningen (or OEningen), Germany ( Lutz et al. 2000; Berger et al. 2005).

Diagnosis. As for the genus.

Description. A thorax with the four wings in connection; one forewing is nearly complete but the three other wings are much more fragmentary. Meso-metathorax large, 10.5 mm long, 6.2 mm wide; wings hyaline; forewing 38.1 mm long, 7.8 mm wide, 6.2 mm wide at nodus level; distance from base to arculus 5.1 mm; from arculus to nodus 6.9 mm, from nodus to pterostigma 19.3 mm; nodus in a basal position; pterostigma long and broad, 4.5 mm long, 1.0 mm wide, covering four cells; pterostigmal brace absent; distance from wing base to Ax1 2.4 mm, from Ax1 to Ax2 2.7 mm, Ax2 aligned with arculus; discoidal cell unicellular, 1.4 mm long, 1.2 mm wide, distinctly broadened in its distal part, basal side 0.7 mm long, anterior side 0.7 mm long, posterior side 1.4 mm long, distal side MAb 1.2 mm long; ScP crossing through nodus as in Stenolestes Scudder, 1895; nodal crossvein very slightly oblique; subnodus nearly perpendicular to RA and RP; 15 postnodal crossveins preserved (probably 17 in fact), not aligned with the 16 postsubnodal crossveins; bases of RP 3/4 and IR2 between arculus and nodus, nearly at mid way between the two, base of RP 3/4 3.0 mm from arculus; base of RP 2 seven cells and 7.3 mm distal of subnodus; base of IR1 six cells and 7.4 mm distally; oblique crossvein ‘O’ not preserved, but probably about four cells distal of base of RP 2; cubito-anal area with two rows of cells between CuA and posterior wing margin; CuA reaching posterior wing margin just distal, 1.2 mm distal, of nodus level; CuA strongly curved; area between MP and posterior wing margin very broad, with 14 rows of cells; postdiscoidal area narrow, with one row of cells, without secondary longitudinal vein between MP and MA; area between RP 3/4 and MA very narrow, without secondary longitudinal vein in between, between their bases and two cells basal of pterostigma; one row of cells between RP 3/4 and IR2 and between RP 1 and IR1; two rows of cells between IR1 and RP 2 opposite pterostigma, but only one more basally. Hindwing very similar to forewing; oblique vein ‘O’ present, three cells distal of base of RP 2; discoidal cell more elongate and narrower than in forewing, with distal side directed toward wing apex and anterior and posterior sides more parallel than in forewing, length of basal side 0.5 mm, of posterior side 1.7 mm, of distal side 1.1 mm, of anterior side 0.9 mm.

Discussion. This fossil can easily be attributed to the Sieblosiidae on the basis of the main diagnostic characters of the family, viz. ScP crossing through nodus, nodal crossvein and subnodus nearly vertical, discoidal cell of forewing very broad, with anterior and posterior sides not parallel and distal side much longer than basal side, oblique vein present; bases of RP 3/4 and IR2 between arculus and nodus; long pterostigma, without pterostigmal brace; base of RP 2 well distal of subnodus; numerous postnodal crossveins; CuA short, with cubito-anal area broad.

Following the phylogenetic analysis of the Sieblosiidae of Nel et al. (2005a), Germanostenolestes gen. nov. falls in the clade [Sieblosia & Miostenolestes & (Paraoligolestes + (Parastenolestes + Stenolestes ))] on the basis of the synapomorphy ‘ScP crossing through the nodus’. It falls in the clade (Paraoligolestes + (Parastenolestes + Stenolestes )) on the basis of the synapomorphy ‘part of CuA distal of nodus level shorter than proximal part’, although this character is also present in Italolestes Nel et al., 2005, but the latter has a narrower discoidal cell in the forewing, with anterior and posterior sides nearly parallel, unlike Germanostenolestes (Hagen 1856; Nel et al. 2005a, b). Germanostenolestes differs from Paraoligolestes Nel and Escuillié, 1993, in the same character, plus the base of IR 1 in a much more distal position than in Paraoligolestes (Nel and Escuillié 1993; Nel et al. 2005a). It differs from Stenolestes Scudder, 1895, in the very narrow area between RP 3/4 and MA with only one row of cells between their base and two cells basal of pterostigma ( Scudder 1895; Nel and Papazian 1986; Nel 1986; Nel and Escuillié 1992; Nel and Paicheler 1994; Riou and Nel 1995; Nel et al. 1997, 2005a). Germanostenolestes shares with Parastenolestes Nel and Paicheler, 1994, this area comparatively narrower than in Stenolestes, which would support a sister-group relationship between the two genera, but it differs from this last genus in the less numerous and non elongate cells in the cubito-anal area ( Nel and Paicheler 1994). Nevertheless, the area between RP 3/4 and MA is broader in Parastenolestes than in Germanostenolestes . The only problematic species to compare with Germanostenolestes lutzi is Stenolestes hispanicus Nel, 1991 , which is based on the basal half of a forewing, with distal half of area between RP 3/4 and MA not preserved. The forewing base of S. hispanicus is also very similar to that of Germanostenolestes , especially in the cubito-anal area ( Nel 1991). But Germanostenolestes lutzi differs from S. hispanicus in its base of RP 2 seven cells distal of subnodus instead of five. It remains that the present discovery of the new genus Germanostenolestes renders uncertain the generic position of S. hispanicus . Nevertheless, we prefer to maintain it in the genus Stenolestes because there is no argument to remove this species from it.

Germanostenolestes is the second Sieblosiidae from Öhningen, the first species being Stenolestes iris Scudder, 1895 , type species of Stenolestes. It can easily be separated from S. iris on the basis of the width of the area between RP 3/4 and MA but also on the presence of only two rows of cells between IR1 and RP 2 ( Scudder 1895: pl. 6, fig. 3).

Heer (1849) described the (sub)genus Sterope for ‘ Sterope parthenope ’ from Öhningen. Unfortunately the location of its type specimen is unknown. After the original drawings of Heer (1849: pl. 3, fig. 11-11a), it shares with Germanostenolestes the presence of only one row of cells between IR1 and RP 1 (unlike Stenolestes iris ) and similar cubito-anal areas, but it differs from Germanostenolestes in its broad area between RP 3/4 and MA with four secondary longitudinal veins. Sterope parthenope is very probably a Sieblosiidae , but its type specimen should be redescribed, if still existing.

Figures

FIGURE 1. Germanostenolestes lutzi gen. and sp. nov., holotype 59573, photograph of habitus, photograph copyright P. Crabb (Natural History Museum, London).

FIGURE 2. Germanostenolestes lutzi gen. and sp. nov., holotype 59573, reconstruction of right forewing (scale bar represents 5 mm).

FIGURE 3. Germanostenolestes lutzi gen. and sp. nov., holotype 59573, reconstruction of right hindwing and pterostigma (scale bar represents 5 mm).