Linnaeomyia, Jaschhof, Mathias & Jaschhof, Catrin, 2015

Jaschhof, Mathias & Jaschhof, Catrin, 2015, Linnaeomyia hortensis gen. et spec. nov. (Diptera: Cecidomyiidae, Porricondylinae) from a backyard site in Öland, Sweden, Zootaxa 4018 (2), pp. 292-296 : 293-294

Linnaeomyia gen. nov.

Type species Linnaeomyia hortensis spec. nov., described below. Monotypic.

Diagnosis. The new genus shows most of the characters typical of the tribe Dicerurini : the circumfila of males have long posterior extensions; male gonocoxites are lacking processes; parameres are fused medially into a tegmen; and parameral apodemes are curved ventrolaterally to form conspicuously long crescents ( Jaschhof & Jaschhof 2013: 109f.). In Jaschhof & Jaschhof’s (2013: 110f.) key to the genera of Dicerurini , Linnaeomyia would fall under Neurepidosis Spungis, 1987 (but see the remarks below), a genus of 10 Palearctic species. However, unlike all the other dicerurine genera, including Neurepidosis , the gonostyli in Linnaeomyia have a large plate-like spine apically and another large hook-like spine ventromedially ( Figs 2–3 ). If spines occur at all in other Dicerurini they are spike-like and form combs or brushes. Another unusual character of Linnaeomyia is the vestigial ejaculatory apodeme ( Figs 2, 4 ). (Note that the ejaculatory apodeme is missing in Dirhiza Loew, 1850 , a dicerurine genus of three or four species that are morphologically aberrant in several respects; cf. Jaschhof & Jaschhof 2013: 132ff.). The only such instance among the Dicerurini described in the past is Neurepidosis decorata Jaschhof, 2013 , whose ejaculatory apodeme is thin, poorly sclerotized, and lacking the strongly broadened base that is found in other Neurepidosis ( Jaschhof & Jaschhof 2013: fig. 67B). The relatively simple tegmen in Linnaeomyia ( Fig. 4 ) differs from that in Neurepidosis , where it is tube-like and terminates in a funnel-shape, as well as from that in many other Dicerurini , where the tegmen bears barbs or processes. Another character peculiar to Linnaeomyia , but one that is hard to assess, is the presence of a large, membranous, conspicuously wrinkled structure filling the space between the gonocoxites and the tegmen. An obvious, exposed outgrowth of that structure is the small lobe ventromedially on the gonocoxites ( Fig. 2 ). With all these apomorphic characters it is impossible to classify Linnaeomyia hortensis —the only species included in our new genus—elsewhere in the Dicerurini , unless one excessively expanded the generic concept of Neurepidosis .

Remarks. In the above-mentioned key to Dicerurini genera, couplet 5 should be slightly modified in order to incorporate Linnaeomyia , as follows:

5 Gonostylus with a pectinate claw or brush of spiky spines ........................................................................................ 6 - Gonostylus without spiky spines, but exceptionally with 2 large, plate- or hook-like spines .................................... 8

Beginning with couplet 11, the key should read as follows:

11 Circumfila present on flagellomeres 1 to 11–12, with long posterior extensions .................................................... 12 - Circumfila present on flagellomeres 1–8, with short or without posterior extensions .................................................. .............................................................................................................................. Desertepidosis Mamaev & Soyunov 12 Gonostylus without spines. Ejaculatory apodeme usually long and with conspicuously broadened base .................... .................................................................................................................................................... Neurepidosis Spungis - Gonostylus with 1 large spine both apically and ventromedially. Ejaculatory apodeme vestigial ................................ ................................................................................................................................ Linnaeomyia Jaschhof & Jaschhof

Other male characters. Head. 14 flagellomeres; flagellomere necks without microtrichia; circumfila on first to eleventh flagellomeres, sinuous, with 1–2 long posterior extensions. Palpus 4-segmented, shorter than head height. Thorax. Anepisternum asetose. Anepimeron with 2 setae. Metepisternum asetose. Scutum with sparse lateral and dorsolateral setae. Legs. Basitarsi without spines. Acropods (claws and empodia) missing in the only available specimen. Wing ( Fig. 5 ). 3.5 times longer than wide. Membrane with macrotrichia. Costal cell small. Rs slightly oblique. R-m + mcu sinuous. M absent. CuA branched; CuA1 weak, basally free, not reaching wing margin; CuA2 running almost parallel and close to wing margin. Abdomen. Pleural membrane asetose. Sclerites poorly sclerotized, with sparse long setae.

Female and preimaginal stages unknown.

Relationships. Morphological evidence (overall similarity) suggests a close relationship between Linnaeomyia and Neurepidosis (see above). As outlined by Jaschhof & Jaschhof (2013), we are just beginning to uncover the generic diversity of Dicerurini , so it is too early to clearly discern intergeneric relationships. In particular, the Dicerurini outside Europe remain virtually unknown. Recent research into the Diptera diversity of a Costa Rican cloud forest ( Borkent & Brown 2015) revealed a remarkably rich diversification of Dicerurini , including several new genera, all yet undescribed (Jaschhof, unpublished).

Etymology. The name refers to the famous Swedish naturalist Carl Linnaeus (1707–1778), also known as Carl von Linné, and to the research station on Öland bearing his name, Station Linné, the type locality of Linnaeomyia hortensis . The suffix – myia, meaning fly, is commonly used in generic names of Diptera and Cecidomyiidae .

Figures

FIGURES 2 – 5. Morphology of male Linnaeomyia hortensis. 2: Genitalia, ventral. 3: Gonostylus, ventral. 4: Tegmen and ejaculatory apodeme, ventral. 5: Wing, vestiture omitted. Tg 9 = ninth tergite; ejac ap = ejaculatory apodeme. Scale for 2 – 4, 0.05 mm; for 5, 0.50 mm.