Mirlatia, Hausmann & László & Mayr & Huemer, 2023

Hausmann, Axel, Laszlo, Gyula M., Mayr, Toni & Huemer, Peter, 2023, Surprising discovery of an enigmatic geometrid in Croatia: Mirlatia arcuata, gen. nov., sp. nov. (Lepidoptera, Geometridae), ZooKeys 1183, pp. 99-110 : 99

Genus Mirlatia gen. nov.

Type species.

Mirlatia arcuata sp. nov. (by monotypy).

Description

(Figs 1 - 6 ). External morphology. Head. Head medium-sized, compound eye relatively large, labial palp narrow, length 1.1 × the diameter of eye in male, 1.5 × in female. Proboscis well developed. Male antenna distinctly bipectinate, length of longest branches 1.6 mm, approximately 10 × the diameter of flagellum, branches checkered black and white; female antenna distinctly bipectinate, longest branches 4-5 × the diameter of flagellum. Thorax (wings, legs). Forewing costa and dorsum slightly, termen markedly convex, apex pointed; hindwing termen distinctly arcuate in both sexes. Transverse lines diffuse, hardly discernible. Venation: forewing with double areole; R2-4 and R5 arising connate from tip of second areole, M1 and R5 shortly stalked laterally on second areole; hindwing with long fusion of Sc+R1 and Rs, distal parts of Rs and M1 completely fused, M2 arising shortly below cell apex (caudad); discocellular cross vein of hindwing distinctly incurved. Male frenulum well developed as a single bristle. Legs long and narrow, spur formula 0-2-4 in male, 0-2- x in female (hindlegs of the examined specimen are missing). Male foreleg with long, black, narrow epiphysis arising from middle of tibia.

Abdomen. Tympanal organ (Fig. 4 ). Ansa of tympanal organ very broad at base, gradually tapered, neither dilated medially, nor at apex with hammer-shaped dilation, tip truncate, with a few micro-spinules in the male.

Genitalia. Descriptions of the male and female genitalia are provided under the description of the type species of the new genus.

Differential diagnosis.

Presence of paired tympanal caves with ansa at the base of the abdomen clearly proves the assignation of the new genus to the family Geometridae . Mirlatia is distinguished from the vast majority of members of the subfamily Ennominae by the tubular M2 vein of the hindwing and the long fusion of hindwing veins Sc+R1 and Rs. It differs from the genera of the subfamilies Ennominae , Geometrinae , Larentiinae , and Sterrhinae by the very broad base and in the lacking apical dilatation of the tympanal ansa. So far, no other geometrid is known to display a similarly shaped ansa, although a broad ansa basis is found in Archiearinae , Desmobathrinae , and Alsophilini , but these groups have an ansa with a pointed tip. The new genus differs from the vast majority of geometrid genera also by the long pectination of the female antenna.

Genetic data, phylogeny.

The genetic data are summarised under the species description. The COI barcode suggests a largely isolated position within Geometridae . The new genus is tentatively placed in the subfamily Larentiinae , supported by the double forewing areole and the hindwing venation with presence of the M2 vein and long fusion of Sc+R1 and Rs. Further aspects of the phylogeny are discussed later in this paper.

Etymology.

The new generic name Mirlatia is introduced as a feminine noun. It is an aggregate of the stems of two latin words, i.e. mir - (stem of the noun mirum, mira meaning surprise(s)) and lat - (latum, the perfect participle form of the verb ferre meaning to bring, referring to the rather surprising discovery of this curious new geometrid moth.

Figures

Figure 1. Adult. Mirlatia arcuata sp. nov., holotype, male (coll. TLMF).

Figure 4. Tympanal organ. Mirlatia arcuata sp. nov., female paratype, slide No.: LG 3352 (prep. G. Laszlo, coll. NHMV). Scale bar: 1 mm.

Figure 6. Mirlatia arcuata sp. nov., female genitalia, paratype.