Planetella adami Ševčík & Hippa, 2023

Ševčík, Jan, Hippa, Heikki, Burdíková, Nikola, Sopuch, Kryštof, Skuhravá, Marcela & Bruun, Hans Henrik, 2023, Integrative taxonomy of Central European Planetella (Diptera: Cecidomyiidae) indicates high species diversity, intraspecific variation and low host specificity, Acta Entomologica Musei Nationalis Pragae 63 (2), pp. 413-450 : 424-425

Planetella adami Ševčík & Hippa sp. nov.

( Figs 6A–D , 13E,F )

Type material. HOLOTYPE: J, Slovakia , Cerová vrchovina Protected Landscape Area , Steblová skala Nature Reserve, 15.vi.–12.vii.2017, Malaise trap in a forest steppe, leg. J. Roháček & J. Ševčík, specimen after DNA extraction (No. PLA61 ),prepared on slide (coll. NMPC) . PARA- TYPEs: SLOVAKIA: 1 ♀ with the same data as holotype, specimen after DNA extraction (No. PLA 61b) (coll. SMOC); 2 JJ, Cerová vrchovina Protected Landscape Area, Vodokáš, 15.vi.–12.vii.2017, Malaise trap in Quercus cerris forest, leg. J. Roháček & J. Ševčík, specimens after DNA extraction (No. PLA 64b,c) (coll. JSL-UOC).

Additional material examined. SLOVAKIA: 1 J, Cerová vrchovina Protected Landscape Area, Steblová skala Nature Reserve, 15.vi.–12. vii.2017, Malaise trap in a forest steppe, leg. J. Roháček & J. Ševčík, specimen after DNA extraction (No. PLA 62), prepared on slide (coll. JSL-UOC).

DNA sequences. DNA sequences (COI barcode region, 28S, 16S) taken from the holotype (No. PLA 61) are deposited in GenBank. Their Accession numbers are provided in Table 1.

Diagnosis. This species is characterized by 15 flagellomeres (binodose, except the shorter apical one), eyes with an eye-bridge, palpus with 4 short palpomeres, and details of male terminalia (aedeagus reaching to about 2/3 of the length of gonocoxite, hypoproct almost as long as aedeagus, apically slightly excavated, gonostylus narrow, apically rounded, see Figs 6C,D ).

Etymology. This species is named after the son of the first author, Adam Ševčík, who was born in 2017 when the type material was collected.

Description. Male. Wing length 7.0 (holotype). Overall body coloration: mostly dark brown, legs and halteres light brown.

Head. Dark brown. Eyes with a distinct eye-bridge, which is membranous, without ommatidia. Antennal flagellum with 15 flagellomeres, F1–F14 with two nodes and three sets of looped circumfila, the apical flagellomere (F15) shorter (about two thirds as long as F14), uninodal but with three rows of circumfilial loops. Flagellomere 1 ( Fig. 13E ) about 3.75 times as long as broad, longer and less constricted than the other flagellomeres. Flagellomere 4 ( Fig. 13E ) 2.9 times as long as broad. Maxillary palpus with 4 palpomeres, P1 to P3 subequal in length, the apical one shorter than the previous ones.

Thorax mostly dark brown, scutum laterally light brown with three dark longitudinal stripes. Scutellum light brown with black lateral lining. Lateral pleura mostly dark brown. Scutum distinctly produced above the head.

Wing elongated, about 2.7 times as long as broad. Veins C, R 1, R 5 and Cu-stem distinct. R 1 joining C in the middle of wing. R 5 reaching C beyond wing apex. Rs indistinct. M

4

indistinct. CuA with dark stem and bent downwards.

Legs with tarsal claws narrow, slightly longer than maximum tarsal diameter, only slightly bent.

Abdomen dark brown, with a light transverse oval spot on each side of the tergite.

Terminalia ( Figs 6C,D ). Gonocoxite relatively narrow, about 2.4 times as long as broad, mediobasally with a large but relatively narrow microtrichose lobe. Gonostylus narrow, slightly curved, slightly broader in apical half, about 4.4 times as long as broad and 0.6 times as long as gonocoxite, apically with a rounded, transversely grooved dark lobe, pointed medially. Cerci very short, apically bluntly pointed, basally fused. Hypoproct relatively narrow, with a shallow posterior depression, slightly shorter than aedeagus, covered with relatively short setae.Aedeagus elongate, subtriangular, reaching to 3/4 of gonocoxite.

Female (associated with holotype male by COI sequence). Similar to male but darker.Antennae much shorter than in male, about as long as thorax, and thinner. Eyes with a narrow eye-bridge. Antennal flagellum with 15 cylindrical flagellomeres.Abdomen not distinctly pointed, segment 8 relatively broad and of similar size as previous segments. Cercus relatively small, one-segmented.

Variation. We noted remarkable variation in coloration and some morphological characters among the specimens studied. One male has distinctly light, whitish abdomen, bicoloured thorax, more excavated apical part of hypoproct ( Figs 6A,B ), and cerci apically rounded. We consider this as a mere intraspecific variation because all DNA sequences (COI, 28S, 16S) of this aberrant specimen are 100% identical with the holotype. Alternatively, if we do not accept DNA species concept, the specimen may represent a potentially separate species with the same DNA sequences as the closely related species, which we consider as highly improbable, although several cases of barcode (or BIN) sharing in Sciaroidea were reported in the literature ( KJAERANDsEN 2022), all of them in the family Mycetophilidae .

Biology. Host plant and galls are unknown. All the type specimens were collected at the edge of a thermophilous Quercus cerris forest.

Discussion. This species belongs to the group of species with 14 to 15 flagellomeres, eye-bridge present, overall dark coloration, currently containing five very similar species, P. adami sp. nov., P. atrobrunnea sp. nov., P. csabai sp. nov., P. muranica sp. nov., and P. thermophila sp. nov., see the key above. They differ only in tiny details on the male terminalia, especially in the shape of hypoproct. Interestingly, K2P distances in COI sequences among these species are relatively high (all more than 5%), see Table 3, allowing their safe identification according to DNA sequences. The closest species to P. adami sp. nov., in terms of K2P distance, is P. muranica sp. nov., with 8.2% distance ( Tab. 3).

Figures

Fig. 6. Male terminalia in ventral (A, C, E) and dorsal (B, D, F) view. A, B (specimen No. PLA62) and C, D (holotype, No. PLA61) – Planetella adami Ševčík & Hippa sp. nov. E, F – P. aestivalis Ševčík & Hippa sp. nov. (holotype). Scale 0.1 mm.

Fig. 13. Antennal flagellomere 4 (except flagellomere 3 in H) and outline of flagellomere 1 with or without associated pedicellus and scapus. A – Planetella granifex (Kieffer, 1898), B – P.gallarum (Rübsaamen, 1899), C – P.fasciata (Meigen, 1818), D – P. aestivalis Ševčík & Hippa sp. nov.(holotype), E, F – P. adami Ševčík & Hippa sp. nov. (holotype), G – P. antennata Ševčík & Hippa sp. nov. (holotype); H – P. atrobrunnea Ševčík & Hippa sp. nov. (holotype); I – P. csabai Ševčík & Hippa sp. nov. (holotype). Scales: 0.1 mm.