Aprionus internuntius Jaschhof, 2003

Jaschhof, Mathias & Jaschhof, Catrin, 2020, An update of Micromyinae (Diptera: Cecidomyiidae) taxonomy, with descriptions of a new genus and 13 new species from Northern Europe, Zootaxa 4750 (3), pp. 349-369 : 366-367

Aprionus internuntius Jaschhof

Our earlier decision to synonymize A. internuntius Jaschhof, 2003 with A. stylifer Mamaev, 1998 is reversed here ( Jaschhof & Jaschhof 2009: 242). Fresh specimens of A. internuntius we recently obtained from various sites in southern Sweden were instrumental in helping us realize that there are subtle but stable distinctions in their morphology, which are described below. In Sweden, A. internuntius tends to be more southerly distributed (Skåne, Östergötland, Uppland) than A. stylifer (Uppland, Västerbotten, Pite Lappmark, Norrbotten, Lule Lappmark), with some overlap in the hemiboreal zone. Our reexamination of the A. stylifer material in the NHRS and SDEI ( Jaschhof & Jaschhof 2009: 242) showed that most specimens were correctly identified in the past, confirming this species to be present in Norway (Akershus, Finnmark) and Finland, whereas other specimens proved to be misidentified, representing the first findings of A. internuntius in Norway (Akershus, inner southern Nordland). The Akershus site, in southern Norway, is remarkable for being the only place where both species were found to co-occur. Another misidentification we noticed is a specimen from Russian Karelia labeled as A. stylifer (spn. FENN 2175 in NHRS), which our reexamination revealed to belong to neither A. stylifer nor A. internuntius but to an unnamed Aprionus .

Diagnosis. Within the A. flavidus (Winnertz) group ( Jaschhof & Jaschhof 2009: 228 ff.), both A. internuntius and A. stylifer are distinguished by the finger-like processes of the tegmen being unusually thin and situated in a cavity near the apex rather than in the center. As a distinction, in A. internuntius the cavity is slightly larger and more clearly defined ( Jaschhof 2003: fig. 2C) compared with A. stylifer ( Jaschhof & Jaschhof 2009: fig. 77C). A more obvious difference is the posterior edge of the subanal plate, which in A. internuntius is markedly concave medially and equipped with two short processes laterally, whereas in A. stylifer it is nearly straight with inconspicuous, lateral sclerotizations (see fig. 2C versus fig. 77C). A peculiarity of the subanal plate of A. internuntius is that the central portions often have a few setae. Finally, the two teeth on the gonostylus of A. internuntius are slightly stronger than those in A. stylifer , which however can be appreciated only in specimens compared side by side.

Material examined. Sweden: 1 male, Skåne, Simrishamn , Stenshuvud NP, mixed broadleaf forest, 26 May–28 June 2010, MT, MCJ (spn. CEC 2708 in SDEI) ; 2 males, Östergötland, Ödeshög, Omberg, Storpissan NR, emergence trap on Norway spruce log, 19 June–30 August 2009, MCJ (spns CEC2709 – CEC 2710 in SDEI) ; 3 males, Uppland, Knivsta, Rickebasta , alder swamp forest, 12 June–24 July 2010, MT, MCJ (spns CEC2711 – CEC 2713 in SDEI) ; 7 males, Uppland, Uppsala , Ekdalen NR, young broadleaf forest with old oak trees, 17 May–2 June 2004, MT, SMTP (trap 27, collecting event 486) , 9–26 May 2005 (collecting event 1700), 26 May–13 June 2005 (collecting event 1701), 27 June–17 July 2005 (collecting event 1703), 20 July–3 August 2005 (collecting event 1035) (spns CEC2714 – CEC 2720 in NHRS); 1 male, Uppland, Älvkarleby, Båtfors, pine forest, 29 July–13 August 2003, MT, SMTP (trap 7, collecting event 3058) (spn. CEC 2721 in NHRS) .