65 (2): 373 – 381 2015 © Senckenberg Gesellschaft für Naturforschung, 2015 Morphological re-examination reveals that Campylomyza serrata Jaschhof, 1998 is a complex of five cryptic species (Diptera: Cecidomyiidae, Micromyinae) With 13 figures Mathias Jaschhof 1 1 Station Linné, Ölands Skogsby 161, SE-38693 Färjestaden, Sweden. – [email protected] Published on 2015-12-21 Zusammenfassung Die zur Unterfamilie Micromyinae gehörende Gallmücke Campylomyza serrata wurde vom Autor im Jahre 1998 nach drei Männchen von einem norddeutschen Fundort beschrieben. Seitdem wurden zahlreiche nachträglich gesammelte Exemplare aus mehreren europäischen Ländern dieser Art zugeordnet und als C. serrata publiziert. Nun, fast 20 Jahre später, wurden alle diese Exemplare und einige andere aus bislang undeterminiertem Campylomyza-Material in der Sammlung des Autors – insgesamt 56 Männchen – zusammengezogen und morphologisch nachuntersucht. Im Ergeb- nis dieser Untersuchung wurde offenbar, dass Campylomyza serrata sensu Jaschhof (1998) ein Komplex aus fünf Kryptospezies ist, einschließlich Campylomyza angulata spec. nov., Campylomyza appendiculata spec. nov., Campylo- myza lapponica spec. nov. und Campylomyza zwii spec. nov. In der vorliegenden Arbeit werden Campylomyza serrata und die ihr nahe verwandten Arten aufgrund von Genitalmerkmalen der Männchen definiert. Ein Schlüssel zur Bestimmung der Männchen wird vorgelegt, der die genannten Arten und Campylomyza spinata, den sechsten Vertre- ter der serrata-Gruppe, einbezieht. Schließlich werden Bestimmungsprobleme diskutiert, wie sie bei der praktischen Arbeit an der serrata-Gruppe (und anderen schwer bestimmbaren Micromyinen) auftreten. Key words Palearctic region, gall midges, species identification, morphology, DNA barcoding Summary The micromyine gall midge Campylomyza serrata was described by the author in 1998 on the basis of three male specimens from a single locality in Northern Germany. Since then, a number of additional specimens from several European countries were assigned to this species and published as C. serrata. Now, almost 20 years later, all these specimens plus a few others from previously undetermined Campylomyza material in the author’s collection, alto- gether 56 males, were gathered for a morphological re-examination. As a result, Campylomyza serrata sensu Jaschhof (1998) is revealed to be a complex of five cryptic species, including Campylomyza angulata spec. nov., Campylomyza appendiculata spec. nov., Campylomyza lapponica spec. nov., and Campylomyza zwii spec. nov. In the present paper, Campylomyza serrata and the new species related to it are defined using characters of the male genitalia. A key is provided that facilitates the identification of males of these species and of Campylomyza spinata, the sixth known member of the serrata group. Finally, various issues related to the identification of serrata-like species (and other taxo- nomically difficult Micromyinae) are discussed. ISSN 0005-805X DOI: 10.21248/contrib.entomol.65.2.373-381 373 Powered by TCPDF (www.tcpdf.org) Jaschhof, M.: Revision of the Campylomyza serrata complex New taxa Campylomyza angulata spec. nov., Campylomyza appendiculata spec. nov., Campylomyza lapponica spec. nov., Campy- lomyza zwii spec. nov. Introduction The genus Campylomyza Meigen provides a prime presented, based on characters of the male genitalia, so example of the difficulties involved in the morphological as to facilitate the morphological identification of hidden identification of gall midges of the subfamily Micro- biodiversity in this difficult group. Specimens in my myinae. With 34 extant, mostly Palearctic species named, collection indicate the presence of another one or two this genus is medium-sized, but one may expect that serrata-like species in Europe, but this material is insuf- there are many undescribed species, several of which are ficient for description. The serrata group has, to present known to the author and many more not yet collected. knowledge, an exclusively Palearctic distribution, but I At present, male genitalia provide the only morphological would not be surprised to learn of its presence in North characters diagnostic of species. Structures of taxonomic America where Campylomyza has been poorly studied. relevance are the gonocoxites, gonostyli and parameres, Finally, I take this opportunity to reflect about evolution– the latter joined to form a tegmen. All these parts are not of Campylomyza or Micromyinae but of the skills of a distinguished by a complex three-dimensional structur- morphotaxonomist. ing. This complexity, on the one hand, provides us with a number of potentially useful characters; on the other hand, character states are difficult to understand from the Material and Methods essentially two-dimensional picture seen with a transmit- ted-light microscope, which is the standard method used Specimens of Campylomyza serrata sensu Jaschhof in the routine identification of Micro myinae species. (1998a) studied here came from the Naturhistoriska There is also the fact that even the slightest distortions Riksmuseet Stockholm (NHRS), the Senckenberg of such tiny structures may cause dramatic changes in Deutsches Entomologisches Institut Müncheberg (SDEI), appearance–something known to careful students of and undetermined material in the author’s collection at these midges as preparation artifacts (cf. Jaschhof & Station Linné, Öland, Sweden. Specimens are returned Jaschhof 2009: 31f.). Like most other Micromyinae, to their holding institutions, and those that were previ- Campylomyza are very small, with body length of usually ously unidentified are shared between NHRS and SDEI. less than 2 mm. The material, available as microscope slide preparations, The Holarctic species of Campylomyza have twice was studied by transmitted-light microscope at 400-times been the subject of taxonomic revision in recent years or lower magnification. The routine of preparing and (Jaschhof 1998b, Jaschhof & Jaschhof 2009). An studying specimens of Micromyinae has repeatedly been improvement to the 2009 revision is that two elusive described, most recently by Jaschhof and Jaschhof taxa, Campylomyza flavipes Meigen, 1818 and Campy- (2009). In the illustrations given here, arrows indicate the lomyza ormerodi (Kieffer, 1913), could be shown to be most relevant diagnostic characters. Morphological terms species complexes. Careful study of new material at that that are not commonly used are explained in Figures 5–7. time revealed the flavipes group to contain 9, and the Identifications and distribution data given here make ormerodi group to contain 6 distinct species (Jaschhof & those published earlier for C. serrata (Jaschhof 1998b, Jaschhof 2009). The serrata group, which is the subject 2009; Jaschhof & Jaschhof 2009; Jaschhof et al. 2014) of the present paper, was established by Jaschhof & obsolete. Jaschhof (2009) for 2 species: the widespread European Campylomyza serrata Jaschhof, 1998 and the Far East Russian Campylomyza spinata Jaschhof, 1998. Taxonomy Here I demonstrate that Campylomyza serrata sensu Jaschhof (1998a) is actually a group of five cryptic species. Campylomyza serrata group This insight is not so much the result of studying new specimens but rather of studying previously known spec- Species of the serrata group are characterized by the imens again, this time in a body. Acquired experience in tegmen that has a pair of finely serrate processes assessing slight morphological differences also plays a role (Jaschhof & Jaschhof 2009). The serration is not here. The newly recognized species–Campylomyza angu- obvious in all the specimens studied and is perhaps vari- lata spec. nov., Campylomyza appendiculata spec. nov., able within a species. According to the orientation of Campylomyza lapponica spec. nov., and Cam pylomyza these processes and to the size of the aedeagal head, two zwii spec. nov–are described and Campylomyza serrata subgroups can be distinguished. In Campylomyza spinata is redefined. A key to the species of the serrata group is and C. zwii, which make up one of the subgroups, the 374 DOI: 10.21248/contrib.entomol.65.2.373-381 Powered by TCPDF (www.tcpdf.org) CONTRIBUTIONS TO ENTOMOLOGY : BEITRÄGE ZUR ENTOMOLOGIE — 65 (2) 373–381 processes are turned posteriorly, so as to form the apex of in C. appendiculata (←, Fig. 5). The tegmina of the two the tegmen (←, Fig. 13), and the aedeagal head is large (←, species are clearly different. In C. angulata, the tegmen Fig. 13). In the other subgroup, which contains C. angu- is broadened towards the apex; it has no distinct shoul- lata, C. appendiculata, C. lapponica, and C. serrata, the ders (←); its apical margin is more or less clearly angulate tegminal processes are situated subapically dorsome- (←); and the parameral apodemes are of moderate size dially in a longitudinal direction (←, Fig. 11), and the (Figs 2, 4). In C. appendiculata, the medial portion of the aedeagal head is small- (←, Fig. 10) to medium-sized (←, tegmen is parallel-sided; small shoulders are present; the Fig. 7). Another peculiarity of the serrata group is that apical margin is straight (except for the two points medi- the medial gonocoxal bridges, which in Campylomyza are ally that are present in all the species treated here); and usually unmodified, have the tendency to project dorso- the parameral apodemes are longer than in any other medially, either in their entirety (←, Fig. 6) or by sending species of the serrata group (←, Fig. 7). Other diagnostic out narrow processes (Jaschhof