Athyroglossa (Athyroglossa) fennica, Introduction, 2021

Introduction, Jens-Hermann Stuke, 2021, New European species of Athyroglossa Loew, 1860 (Diptera: Ephydridae) from Finland and the Republic of Georgia, Bonn zoological Bulletin 70 (1), pp. 85-95 : 86-88

Athyroglossa (Athyroglossa) fennica spec. nov.

( Figs 1 , 3 , 9 , 15 , 21 )

urn:lsid:zoobank.org:act:374E3C1C-15A0-4EBC-A79F-B0B14159325B

Type material

Holotype. FINLAND: ♂; (1) „ Fl Central Finland / Kolima 3.7 km ese / Pihtipudas / [63,342°N 25,621°E] / 18.vii.2020, leg. Stuke / 2667 [cross written]”. – (2) “Ho- lotypus / Athyroglossa fennica ♂ / spec. nov. ♂ / Stuke det. 2020”. [The specimen is pinned using a minuten and is in excellent condition ( Fig. 1 ). The holotype will be pre- served in the collection of the Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany ( ZMB).].

Paratypes. FINLAND: 1 ♂, 18.vii.2020, Central Finland, Kolima 3.7 km ESE Pihtipudas [63.342°N 25.621°E], leg. Stuke. – 1 ♂, 18.vii.2020, Central Finland, Kolima 8.1 km ESE Pihtipudas [63,310°N 25,670°E], leg. Stuke.

Description (holotype, ♂)

Body length about 2.2 mm. Wing length = 1.9 mm. Head height = 0.6 mm.

Head black. Gena-eye-ratio (in lateral view genal height measured at the maximum eye height:eye height) = 0.8. Antenna black. First flagellomere strongly light brown dusted. Arista black, with 4–5 dorsal rays, basal rays slightly shorter than height of basal aristomere. Eye brown, all ommatidia about same size, no omma- trichia recorded. Eye height-length-ratio (in lateral view maximum eye height:maximum eye length) = 1.2. Ocelli forming an isosceles triangle. Frons with distinct brown dusting surrounding ocellar tubercle and reaching for- ward to ptilinal fissure and posterolaterally to the dorsal eye margin. Frontal triangle indistinct, reaching forward to the ptilinal fissure. Frontal triangle polished, inter- frontal vitta otherwise polished to very fine longitudinal wrinkled. Facial grooves with indistinct facial carina. Ventral face bulging and stretching ventrally beneath the clypeus. Facial grooves and parafacia silver dusted. Clypeus large, slightly wider than high, shiny, slightly microsculptured. Gena large, polished in upper ¾ and microsculptured in ventral ¼. Anteroventral margin and posteroventral margin of gena forming an angle of about 65°. Postcranium brown dusted to subshining. Palpus brown, without setae. Proboscis reaching to mouth edge. 1 ocellar seta; 1 postocellar seta about as long as vertical setae; 1 outer and 1 inner vertical seta; no postorbital setae; 1 distinct reclinate and 1 distinct proclinate fron- to-orbital-seta; 1 large dorsal, 1 smaller but still distinct seta below and 3 minute facial setae; 1 distinct proclinate genal seta.

Thorax black. Scutum finely microsculptured, scutel- lum more roughly microsculptured. Scutum and scutel- lum covered with short, brown, scattered setulae that are not arranged in lines. Scutum medially distinctly dusted, laterally shining. Scutellum subshining to shining. Ane- pisternum with several setulae. Anepimeron, posterior margin of anepisternum, meron, katatergite, subscute- llum and dorsal ⅔ of mediotergite dusted. Other pleu- rae shining. no acrostichal seta; 0+1 dorsocentral seta; 0 prescutellar seta; 1 intra-alar seta; 0 supra-alar seta; 1 small postpronotal seta; 2 notopleural seta, posterior inserted above level of anterior; 0 postalar seta; 1 sub- apical + 3 indistinct lateral scutellar seta, only subapical seta situated on a small tubercle; 1 small katepisternal seta; 1 small anepisternal seta. Wing membrane slight- ly brownish infuscated. Veins brown. Wing complete- ly covered with microtrichia. Alula about four times as wide as long. Dark brown setulae at hind margin of al- ula about twice as long as alula. Costal index I (straight line distance between the apices of R 1 and R 2+3 [section 2 of costa]:straight line distance between the apices of R 2+3 and R 4+5 [section 3 of costa]) = 2.7. Costal index II (straight line distance between the apices of R 4+5 and R 2+3 [section 3 of costa]:straight line distance between the api- ces of Media and R 4+5 [section 4 of costa]) = 2.1. R 4+5 vein-ratio (straight line distance along vein R 4+5 between crossvein r-m and branch of R 4+5 and R 2+3 [Section 1 of R 4+5]:distance apicad of r-m [section 2 of R 4+5]) = 0.1. M vein-ratio (straight line distance along vein M between crossveins dm-cu and r-m [section 1 of M]:distance apicad of dm-cu [section 2 of M]) = 0.6. M vein-ratio (straight line distance along vein M between crossveins dm-cu and r-m:distance apicad of dm-cu) = 0.6. Base and stem of halter brown, knob of halter black. Legs black with tarsi lighter dark brown to yellow. Fore tarsi dark brown, middle and hind tarsi brown. Legs mostly sub- shining, all tibiae shining on dorsal surfaces. Legs cov- ered with small setulae. Fore femur with conspicuous, slightly longer, regular setulae arranged on posteroventral surface, long setae anteroventrally towards the apex of the middle femur and some regularly arranged pos- teroventral setulae at the apex of the hind femur. Mid- dle tibia distally with 2 ventral setae. Metatarsus II-tibia II-ratio (length metatarsus 2:length tibia 2) = 0.5. Fore femur distally with 2 inconspicuous posteroventral short spines.

Abdomen black. Tergites laterally reflexed under. Terg- ites smooth. Tergite 1 completely dusted. Tergites 2 + 3 broadly dusted in the middle with a small shining hind margin, dusted at the anterior margin and dusted at the extreme lateral margin. Tergite 4 broadly dusted in an- terior 2/3 of the middle and at the anterior margin. Terg- ite 5 completely dusted dorsally. Tergites covered with scattered black setulae. Tergite III-IV-ratio (length tergite 3 medially:length tergite 4 medially) = 0.9. Tergite IV- V-ratio (length tergite 4 medially:length tergite 5 medi- ally) = 2.3.

Description of male postabdomen and sternites based on 1 dissected paratype: Sternites 3–5 as shown in Fig. 3 : Sternites 3–4 moderately large, elongated. Sternite 5 di- vided in two triangular sclerites. A small additional scler- ite between sternites 4 and 5. Sternites 3–5 covered with scattered setulae. Epandrium as Figs 9 and 15 : hind mar- gin about as long as cercus, without ventral protuberance and therefore hind margin in lateral view almost straight. Epandrium with minute setulae and hind margin behind cerci with 4 strong setae. Cercus elongated, covered with microtrichia and setae. Surstylus as Figs 9 and 15 : elon- gated, base broadened, dorsally concave, ventrally slightly concave, posterodorsally separated from epandrium, anteriorly upcurved and pointed anteromedially. No set- ulae present on surstylus. Hypandrium as Fig. 21 : with a large anteriorly directed appendix that is almost as long as wide and anteriorly hollowed out. Additionally, with a narrow ventrally directed appendix. Postgonite elon- gated, anteriorly rounded, dorsally almost straight, and ventrally without indentation. Pregonite distinct, slightly shorter than high, dorsally semicircular and ventrally straight.

Variability. The dusting of the frons can cover almost all of the frons. Wing may be almost hyaline. Apical tar- someres may be black.

Female. Female unknown.

Diagnosis. This species is easily recognised by the com- bination of black fore tarsi and long postocellar seta. The only other Palearctic Athyroglossa with black fore tarsi is A. flaviventris (Meigen, 1830) , and it has a reduced postocellar seta. Additional characters to separate both species are given in the key below. With the table of the West Palearctic species presented by Mathis & Zatwarnicki (1990) A. fennica spec. nov. will key out at couplet 4 with the separation of A. flaviventris and A. glabra (Meigen, 1830) where a decision to one of the keys alternatives is not possible anymore. In the key to Nearctic species ( Wirth 1970), A. fennica spec. nov. will be identified as A. glabra .

88 Jens-Hermann Stuke

Etymology. The Latin female adjective “fennica ” de- scribes the known distribution of this new species that is known thus far from central Finland.

Distribution. Although the author visited 128 locations all over Finland to collect Ephydridae and several looked very similar to the locations of A. fennica , this new species was only recorded at two adjacent sites in central Finland.

Ecology. All specimens were collected along man-made shores with sparse vegetation of a lake. One locality is a larger harbour, the other one a small area that is used for fishing and bathing. Such localities are the only locations where collecting Ephydridae was successful at large Finnish lakes. At one of the locations A. glabra occurred together with A. fennica spec. nov.

Figures

Fig. 1. Habitus of Athyroglossa fennica spec. nov., holotype, ♂.

Figs 3–8. ♂; sternites 3–5 (ventral view) of European Athyroglossa. 3. Athyroglossa fennica spec. nov. 4. A. flaviventris (Meigen, 1830). 5. A. glabra (Meigen, 1830). 6. A. kuraensis spec. nov. 7. A. nudiuscula Loew, 1873. 8. A. ordinata Becker, 1896.Abbreviations: S3 = sternite 3; S = sternite 5.

Figs 9–14. Epandrium, surstylus and cercus (dorsal view) of European Athyroglossa. 9. A. fennica spec. nov. 10. A. flaviventris (Meigen, 1830). 11. A. glabra (Meigen, 1830). 12. A. kuraensis spec. nov. 13. A. nudiuscula Loew, 1873. 14. A. ordinata Becker, 1896. Abbreviations: ce: cercus, ep: epandrium, su: surstylus.

Figs 15–20. Epandrium, surstylus, hypandrium and cercus (lateral view) of European Athyroglossa. 15. A. fennica spec. nov. 16. A. flaviventris (Meigen, 1830). 17. A. glabra (Meigen, 1830). 18. A. kuraensis spec. nov. 19. A. nudiuscula Loew, 1873. 20. A. ordinata Becker, 1896. Abbreviations: ce = cercus; ep = epandrium; hyp = hypandrium; hypb = hypandrial bar; phyp = projection of hypandrium; su = surstylus.

Figs 21–26. ♂; Hypandrium (ventral view) of European Athyroglossa. 21. A. fennica spec. nov. 22. A. flaviventris (Meigen, 1830). 23. A. glabra (Meigen, 1830). 24. A. kuraensis spec. nov. 25. A. nudiuscula Loew, 1873. 26. A. ordinata Becker, 1896. Abbreviations: hypb = hypandrial bars; phyp = projection of hypandrium.