Madma oisella, Viertler & Klopfstein & Jouault & Spasojevic, 2022

Viertler, Alexandra, Klopfstein, Seraina, Jouault, Corentin & Spasojevic, Tamara, 2022, Darwin wasps (Hymenoptera, Ichneumonidae) in Lower Eocene amber from the Paris basin, Journal of Hymenoptera Research 89, pp. 19-45 : 19

Madma oisella sp. nov.

Figs 5 , 6

Etymology.

Derived from the locality name: Oise. The word is transformed to resemble the ending of the French word for Miss “Madmoiselle” and latinised.

Material examined.

France • Holotype female; Oise department, region of Creil, Chevrière, Le Quesnoy; 49°20'06.0"N, 2°40'28.9"E; 1998-2000; G. De Ploëg and A. Nel leg.; in amber; MNHN.F. A71347 (PA2189).

Type condition.

Lateral aspects clearly visible through amber; dorsal and ventral aspects partly visible through irregular surface of amber. Complete, except few apical flagellomeres at surface of amber with their ventral side missing. Body translucent, thus parts of body from opposite side often visible below cuticle, as well as some inner structures. Body surface sculpture and carinae weakly visible; outer surface partly covered with dark material, which probably represents remains of organic matter.

Diagnosis.

See genus diagnosis.

Description.

Body around 4.9 mm. Color difficult to interpret, except tip of mandibles darker, hind tibiae clearly darker at base and apex (dark-light-dark), antennae uniformly colored and T1 dark.

Head. Mandibles moderately large, weakly tapered from base to apex, not twisted, with two oblique and subequal teeth; outer surface without strong sculpture, smooth or sparsely pubescent. Malar space moderately long, 0.9 × mandibular width at base, smooth, seemingly without subocular sulcus. Labrum not clearly exposed below clypeus. Clypeus in frontal view subquadrate, transversely undivided and separated from face with weak clypeal groove, in lateral view clearly convex; apical margin simple, truncate, without tooth or tubercles. Face weakly convex with weak median swelling, without upper process. Eyes large, in lateral view 0.85 × head height; inner margin of eyes straight opposite antennal sockets, in frontal view parallel to each other. Modification between antennal sockets absent. Frons without strong impressions for scape. Ocelli of normal size, separated from eyes by more than their diameter. Vertex steeply declivous behind ocelli with straight surface to occipital carina. Occipital carina complete and dorsally evenly convex, high on head, in lateral view almost reaching height of dorsal eye margin. Maxillary palps with five segments, labial palps not visible. Scape about as long as wide, without extended membranous area; pedicel clearly smaller than scape. Flagellum 3.9 mm with 27 segments; first flagellomere 6.25 × as long as wide; median and apical flagellomeres longer than wide; tip of apical flagellomere unmodified.

Mesosoma. Pronotum in profile on left side higher than long, on right side about as high as long (specimen clearly viewed only in slight diagonal position), without latero-ventral posteriorly projecting lobe; pronotal collar not visible; anterior vertical part clearly extended dorsally. Epomia weakly visible, present ventrally, extending laterally but unclear how far. Modifications near base of notauli absent. Mesosternum with epicnemial carina extending laterally on mesopleuron at least to mid-height of pronotum, possibly longer, but dorsal part not visible clearly through amber; not modified behind fore coxae. Posterior transverse carina absent laterally, present in front of mid coxae as a raised flange and in between as a low carina. Mesopleuron evenly convex with sternaulus weakly visible, extending from ventrolateral anterior margin of mesopleuron to posterior margin of mesopleuron clearly above mid-height of mid coxa, bowed upwards around mid-height. Mesopleural furrow with horizontal impression extending from around mid-height to episternal scrobe. Mesoscutum evenly shagreened and matt. Notauli deeply impressed anteriorly, extending posteriorly past centre of mesoscutum but unclear how far. Carina along lateral margin of mesoscutum evenly raised and extending to anterior margin of scutellum. Scutellum in profile flat, smooth, without carinae. Postscutellum evenly convex in profile. Propodeum about as long as high; structure difficult to assess but either smooth or punctured. Metapleuron as long as high, with anteroventral corner extended to a small lobe, without juxtacoxal carina and at most with few rugae lateroventrally. Submetapleural carina difficult to interpret, present only in anterior half or completely absent. Propodeal carination complete, although presence of medial portion of anterior transverse carina uncertain; area basalis shorter than area superomedia; the latter similar in size to area petiolaris. Spiracle subcircular, separated from pleural carina by its own diameter, touching dorsal half of pleural portion of lateral longitudinal carina. Dorsal margin of metacoxal cavities above ventral margin of metasomal cavity. Legs simple, not unusually stout or slender. Fore tibia with small apical tooth. Mid and hind tibia with two long slender spurs. Hind tibia with fringe of parallel setae on inner apex; 1st tarsomere 1.1 × as long as wide; 4th tarsomere apically more or less evenly truncated. Tarsal claws without modification.

Wings. Fore wing 3.8 mm. Areolet oblique pentagonal, 1.5-2.2 × as wide as long, with 3Rs 0.8 × 2Rs, 2 + 3M 2.1 × 2Rs, 4M 0.3 × 2 + 3M; 3rs-m with two bullae. 2m-cu clearly curved outwards, with two bullae. 1Rs + M absent. 1m-cu at level of 1M + 1Rs. Pterostigma 4.3 × as long as wide. Cell 2R1 2.1 × as long as pterostigma, 3.4 × as long as wide. 2Cu 0.8 × 1M + 1Rs, 0.8 × r-rs. 3Cu about same length as 2cu-a. Hind wing with M + Cu curved distally. 1Cu around same length as cu-a. 1Rs 1.2 × as long as rs-m.

Metasoma. Depressed to cylindrical. S1 reaches around middle of T1, anteriorly with a median keel, centrally with a weak median swelling. Presence of laterotergite 1 unclear; if present then membranous on entire length. T1 in dorsal view about 2-2.5 × as long as wide, petiolate, but sides evenly tapering from apex to base as tergite relatively short, in lateral view continuously expanding in profile; spiracle at around 0.6 × T1 length in profile; dorso-lateral carina complete, above spiracle; latero-median carinae long, almost reaching posterior margin, parallel to each other; sculpture shagreened or punctured, but could be an artefact. T2 in dorsal view transverse; sculpture if present not strong and even on entire tergite length; latero-median carinae absent; impressions in anterior half either absent or shallow; thyridium present and shape unclear. Dorsal surface of T3 and remaining tergites evenly convex. T3 and T4 with posterolateral corners rounded. S6 unclear, seems transverse with simple apical margin. T7 conspicuously shorter than T6. T8 short, not elongated in horn or boss. Ovipositor sheaths 0.2 × metasoma length, parallel-sided, with dense short setae. Ovipositor straight and compressed, parallel sided until tip where dorsal valve expanding into nodus; tip of lower valve with at least four distinct oblique teeth.

Figures

Figure 5. Holotype of Madma oisella sp. nov. A lateral view of whole specimen B fore tibia, black triangle points to tooth on apical margin C latero-ventral view showing propodeum and bilobed posterior transverse carina on mesosternum (I) and extended small lobe on metapleuron (II) D lateral view of head E first tergite and sternite F frontal view of face G ovipositor H Detailed photo of fore wing. Scale bar: 2 mm (A); 0.5 mm (B, D-G); 1 mm (H).

Figure 6. Interpretative line drawing of Madma oisella sp. nov. Dotted lines indicate uncertain interpretations. Different detailed photographs were used as templates to create this drawing. Scale bar: 1 mm.