Osmanthedon Kallies, 2018

Agassiz, David & Kallies, Axel, 2018, A new genus and species of myrmecophile clearwing moth (Lepidoptera: Sesiidae) from East Africa, Zootaxa 4392 (3), pp. 588-594 : 589-590

Osmanthedon Kallies gen. nov.

Type species: Osmanthedon domaticola Agassiz & Kallies spec. nov.

Description. Small moths, with a wingspan of 15–19.5 mm ( Figs 1, 2 ).

Head. Proboscis minute, perhaps not functional; labial palpus, basal and second palpomeres rough scaled, distal margin of second palpomere with bristly scales and extending beyond frons, apical palpomere smooth, 2/3 as long as second; frons smooth. Antenna thick, in particular in male, apically abruptly ending, not tapering, ventrally covered with short ciliae, which are slightly longer than the width of the flagellum.

Forewing. Transparent areas densely covered in semitransparent scales. Venation ( Fig. 3 ): forewing with M3 and Cu1 separate, R1 and R2 not fused, R4 and R5 with a short common stalk, hindwing veins M3, Cu1 and Cu2 closely approximated; M3 and Cu1 arise from a common point from the cross vein, without a common stalk.

Abdomen. Anal tuft small in male, in female only laterally developed, terminal segment dorsally and ventrally with very short scales.

Male genitalia ( Figs 4, 5 ). Typical of Synanthedonini (setae bifurcate, scopula androconialis present, phallus without coecum penis); however, the vinculum and tegumen tightly fused, tegumen ventrally membranous, without distinct gnathos, valva with a soft bulbous crista near its centre; base of the valva with well-developed scale or sensilla sockets; ventral margin of the valve with a distinct processus half way; phallus with a distinctly hooked and large cornutus.

Female genitalia ( Fig. 6 ). Antrum very short, ductus seminalis close to ostium, ductus bursae close to antrum distinctly expanded.

Diagnosis. This genus is unique based on at least three autapomorphic character states:

(1) Hindwing veins M3, Cu1 and Cu2 closely approximated (well separated in all other Synanthedonini ). (2) Valva with a soft bulbous crista near its centre (with a distinctly sclerotized ridge-like crista or a dense field of setae near the base of the valva in all other Synanthedonini ).

(3) Valva with sacculus with well-developed scale or sensilla sockets (without in all other Synanthedonini ).

In addition to these unique characters, Osmanthedon differs from most Synanthedonini by the shape of the antennae, which are distinctly thickened and terminate abruptly in Osmanthedon, while they are thinner, clavate and tapering apically in most other Synanthedonini , including Synanthedon Hübner [1819] . However, some South American species currently assigned to Euryphrissa Butler, 1874 , Carmenta Edwards, 1881 and Aegerina Le Cerf, 1917 have similar antennae ( Eichlin 2003; Bartsch, personal communication).

Other characters that distinguish Osmanthedon from most Synanthedonini are as follows:

(1) Forewing veins R1 and R2 not fused (often fused distally, or occasionally completely fused in Synanthedonini ). (2) Forewing veins R4 and R5 with a short common stalk (longer in typical Synanthedonini ). (3) Hindwing veins M3 and Cu1 arise from a common point from the cross vein (with a common stalk in most Synanthedonini ).

(3) Hindwing veins M3 and Cu1 arise from a common point from the cross vein (with a common stalk in most Synanthedonini ).

(4) Male genitalia with vinculum and tegumen tightly fused (connected by a thin membrane in most Synanthedonini ), without any distinct gnathos lobes (well developed in most Synanthedonini ), tegumen ventrally membranous (sclerotized in most Synanthedonini ), ventral margin of the valva with a distinct processus (lacking in most Synanthedonini ); phallus with a distinctly hooked and large cornutus (without in most Synanthedonini ).

(5) Female genitalia with antrum very short (long and well-developed in most Synanthedonini ), ductus seminalis close to ostium (well removed in most Synanthedonini ), ductus bursae distinctly expanded in the section close to the antrum (simple in most Synanthedonini ).

(6) The anal tuft in the female is only laterally developed, terminal segment dorsally and ventrally with very short scales (anal tuft in females very prominent, terminal segment dorsally and ventrally with long scales in most Synanthedonini ).

The new genus shares some characters with Camaegeria Strand, 1914 , which also lacks the sclerotized crista sacculi and has an undeveloped anal tuft in the female. However, the two genera are not similar otherwise (comp. Bartsch & Berg 2012). Superficially, the new genus is also somewhat similar to Osminia and Coccophila Bartsch, 2015 . These genera, however, belong to the tribes Osminiini and Sesiini , respectively, and differ fundamentally by the genitalia and wing venation ( Eichlin 1998; Kallies 2004; Bartsch 2015, 2016).

Etymology. The name derives from the generic names Osminia and Synanthedon , referring to the similarity of the new genus to species of Osminia while indicating its relationship to Synanthedon .

Figures

FIGURES1–6. Osmanthedon domaticola gen. etspec.nov. 1.Male,holotype (alar expanse15 mm).2. Female,paratype (alar expanse 18.5 mm). 3. Venation. 4. Male genitalia, phallus removed. 5. Male genitalia, phallus.6. Female genitalia.