Zadbimyia, Jaschhof, Mathias & Jaschhof, Catrin, 2014

Jaschhof, Mathias & Jaschhof, Catrin, 2014, Zadbimyia, a new genus of asynaptine Porricondylinae (Diptera: Cecidomyiidae) with twenty-two new species from the cloud forest of Costa Rica, Zootaxa 3866 (1), pp. 1-29 : 3-6

Genus Zadbimyia gen. n.

Type species, Zadbimyia costaricensis sp. n.

Diagnosis. Based on males ( Fig. 1 ); females and immature stages are unknown. Zadbimyia can be recognized as an Asynaptini using the key by Jaschhof & Jaschhof (2013: 46). Asynaptini are the only Porricondylinae that regularly have more than 14 flagellomeres and the abdominal sclerites subdivided in two or four raised portions. Zadbimyia is distinct from other Asynaptini based on the following combination of character states: [1] flagellomere necks usually have microtrichia, at least basally ( Fig. 4 D); [2] circumfila, in the typical outline, form a single circumferential band with short, irregular loops ( Fig. 4 D); both [3] labella and [4] palpus are atrophied ( Fig. 2 B–D); [5] vein r-m+m-cu is almost straight to slightly curved or sinuous, i.e. the point where the media is supposed to branch off is obscured ( Fig. 3 ); [6] vein M is absent ( Fig. 3 ); [7] vein CuA1 is absent ( Fig. 3 A) except in one species ( Fig. 3 B); [8] each basitarsus has a spine ventro-apically ( Fig. 2 A); [9] claws are strongly curved ( Fig. 2 E) except in one species ( Fig. 2 F); [10] abdominal tergites are present as a single narrow, medially interrupted band on the posterior margin of segments I–VI (rarely VII); [11] the anterior portions of the gonocoxal apodemes are separated medially, i.e. not merged to form a common shaft ( Fig. 5 C); [12] gonostylus lacks a pectinate claw and is densely microtrichose apically [ Fig. 4 C]; [13] the ejaculatory apodeme is well developed and distinct from the parameres [ Fig. 4 A]; [14] parameres are merged medially to form a structural unit (‘tegmen’); and [15] bear 1–3 pairs of sclerotized processes ventrally to ventrolaterally ( Fig. 4 A).

Male description. Slender, delicate midges, body lengths 1.3–2.0 mm ( Fig. 1 ). Color: body light brown to yellow, with dark setae and scales, latter densely covering legs and halter (trap-collected specimens usually rubbed, vestiture often missing). Head ( Fig. 2 B–D). Eyes covering most of head, in some species narrowed ventrally, at vertex connate, resulting eye bridge 6–11 ommatidia long. Occiput evenly convex, with various sized setae including pair of large dorsal setae. Postfrons asetose. Prefrons extensive, usually well sclerotized. Scape markedly tapered toward base, with setal tuft distomedially, 1.5–2.5 times longer than pedicel, in Z. dubia shorter and conspicuously broad. Number of flagellomeres 16–31 with some intraspecific variation; with distinct necks, barrelshaped to subglobular nodes; in many species necks partly or entirely covered with microtrichia; node, from base to apex, with irregular double whorl of setae, one circumfilum, few to many large sensory hairs arising from hooded alveoli, one whorl of sensory hairs arising from ordinary alveoli; circumfilum typically sinuous, appressed to somewhat bowed, forming irregular loops between adjoining alveoli ( Figs 16 B, 19A); ultimate flagellomere neckless, often with additional apical bud. Clypeus small, with large setae or asetose. Labrum asetose. Labellum vestigial, basal segment tiny, smooth, asetose, apical segment with 1–3 setae. Maxillary protuberance large, in some species elongate ( Fig. 2 D). Palpus atrophied, usually shorter than length of head, with 1–4 segments. Thorax. Scutum with large lateral and dorsocentral setae. Anepisternum and anepimeron setose except in Z. dubia with asetose anepisternum, anepimeral setae twice as long as anepisternal setae. Wing ( Fig. 3 ). About as long as body. Membrane usually tinged slightly gray or gray-brown, costal cell often darker than rest of membrane. Veins: R1 long; Rs short, oblique, in line with R5; R5 slightly curved, progressively departing from C, joining C beyond apex of wing; r-m+m-cu straight to slightly curved or slightly sinuous; M absent; no wingfold anteriad of CuA; CuA1 typically absent ( Fig. 3 A), present only in Z. lasalturas , there forming fork with CuA2 ( Fig. 3 B); CuA2 mostly straight, only distally curved, usually evanescent apically; CuP long, reaching to bend of CuA2. Legs. More than twice body length. Each basitarsus with long, thin spine ventro-apically ( Fig. 2 A). Claws typically strongly curved, a large curved tooth basally, rarely a tiny tooth subapically ( Fig. 2 E); Z. aberrans exceptional with thin, almost straight claws with fine basal tooth ( Fig. 2 F). Empodia and pulvilli rudimentary. Preabdomen. Tergites I–VI (rarely VII) present as narrow, raised, setose, medially interrupted bands on posterior margin of segments, with strikingly large setae, terga VII–VIII largely unsclerotized, asetose. Pleural membrane at least of anterior segments setose, pleural setae 1/3 as long as tergal setae. Sternum I unsclerotized, asetose, sternites II–VIII evenly sclerotized, setose, sternal setae 1/3 to 1/2 as long as tergal setae. Terminalia (see Figs 4 A, 5B–C for specific terms). Tergite IX subtrapezoid, with posterior or lateroposterior setae, posterior margin straight or medially concave, anterior margin membranous, obscured. Gonocoxites broadly united ventrobasally, with posteromedial concavity (= ventral emargination), ventrobasal portion narrowed to various extent, often subrectangular, gonocoxal apodemes with distinct anterior and posterior portions, anterior portions (antGA in species descriptions) maximally as long as distance separating them. Gonostylus robust, curved, tapered toward apex to various extent, with dense, often large microtrichia apically, without spines, subapical bristles usually absent, present only in Z. aberrans and Z. dubia . Ejaculatory apodeme long, strongly sclerotized; ducts of accessory glands usually distinct, joining apodeme near apex. Parameres merged medially, typical outline ( Figs 4 A, 5B) with broad portion basally, usually small, weakly sclerotized apodemes, and narrow, subcylindrical, often seemingly two-pointed portion apicomedially, typically 1–3 pairs of diversely shaped, sclerotized processes and, in some species, pronounced lateral shoulders at transition from basal to apical portions; atypical parameres may occur (see Figs 23 C, 25C). Hypoproct deeply incised, resulting in two rounded lobes apically, each with a few apical setulae. Cerci similar to hypoproct but larger, usually extending beyond level of parameres.

Phylogenetic relationships as inferred from adult morphology. The basic construction of the male genitalia in Zadbimyia is uniform (see character states [11]–[15] specified in the generic diagnosis), and character state [15] can be regarded as a synapomorphy of the included species. Also, the genus contains the only Asynaptini known to have the flagellomere necks completely covered with microtrichia. Zadbimyia and Asycola Spungis , a monotypic genus of Asynaptini from the Palearctic, are the only Porricondylinae with multi-looped circumfila, yet other characters indicate that the two genera are not closely related (see Spungis 1991). Altogether, there is no doubt that Zadbimyia is a monophyletic group. In searching for its closest relatives one is reliant upon fragments of knowledge available for other New World and tropical Asynaptini . Based on this Pseudocamptomyia appears to be closer to Zadbimyia than any other Asynaptini described. The North American type species of Pseudocamptomyia Parnell , P. phosphila (Felt) , resembles Zadbimyia species with respect to character states [3], [4], [6], [7], [10–12] and [14], yet there are a number of differences. Most notably, in P. phosphila circumfila are not looped but are only slightly sinuous; vein r-m+m-cu is strongly sinuous and enters the radius at an almost right angle; each basitarsus has a microtrichose projection rather than a spine ventro-apically; the gonostylus lacks microtrichia and possibly has a small spine apically (which cannot be accurately determined in the two specimens existing of this species); and the ejaculatory apodeme and parameres together form a complex structure, in which the apodeme bears two pairs of apical processes and the parameres one lateral pair. Two species from Somalia, unavailable for our study, were classified in Pseudocamptomyia by Mamaev and Zaitzev (1997). Their genitalia are figured as having processes similar to that of P. phosphila ( Mamaev & Zaitzev 1997: fig. 3b–c), but it is impossible to determine where exactly these processes are inserted. Other important characters were also not adequately described. Regardless of whether these two Afrotropical species are properly placed in the genus Pseudocamptomyia , which remains to be verified, they are certainly closely related to it.

As regards the interspecific relationships of Zadbimyia , there is a large core group of species, including the type species, whose parameres have moderately sized, toothlike processes (see, for instance, Fig. 4 B). It is possible that these species are more closely related to each other than to those exhibiting different types of parameres (see Figs 22 C, 24C, 25C). However, this assumption is not supported by additional evidence, so for the time being it remains uncertain whether or not this core group is monophyletic. Even subsets of the core group, such as those species having two pairs of paramere processes, are usually quite variable regarding other characters, such as the outline of the eye bridge, size of the maxillary protuberance, or coverage of flagellomere necks with microtrichiae. As an exception, Z. costaricensis , Z. browni , and Z. artborkenti correspond in having tarsal claws with a tiny subapical ancillary tooth in addition to parameres of the same outline, so this trio is certainly monophyletic. Various Zadbimyia with unusual parameres, namely Z. spinapiscis , Z. inornata , Z. aberrans , and Z. dubia , suggest a degree of intrageneric complexity that we have only just begun to explore.

All in all, the present body of evidence indicates that Zadbimyia and Pseudocamptomyia belong to one and the same clade of Asynaptini that is distributed in the New World and occurs also in the Afrotropics. This clade appears to be similarly complex and biodiverse as are both Asynapta Loew , with 44 species, and Camptomyia Kieffer , with 65 species, two genera that hitherto accounted for the greater part of world Asynaptini .

Etymology. The generic name, Zadbimyia , is composed of Zadbi -, the abbreviation of Zurquí All-Diptera Biodiversity Inventory, and -Μγία (lat. - myia), the Greek word for fly.

Figures

FIGURE 1. Habitus of male adult Zadbimyia sp., most of wing setae omitted. Scale 1.0 mm.

FIGURE 2. Morphology of male Zadbimyia spp. A: basitarsus of foreleg, dorsolateral, of Z. browni. B: head, lateral, of Z. artborkenti. C: ditto, of Z. anniae. D: ditto, of Z. spinapiscis. E: fifth tarsomere of foreleg, lateral, of Z. browni. F: ditto, of Z. aberrans. Scale for A, E – F, 0.05 mm; B – D, 0.1 mm. clp = clypeus, eye br = eye bridge, fd chnl = food channel, lbl = labellum, lbr = labrum, mx prtb = maxillary protuberance, pfr = postfrons, plp = palpus, prfr = prefrons.

FIGURE 3. Wings of male Zadbimyia spp., setae omitted. A: Z. membranacea. B: Z. lasalturas. Scale 1.0 mm.

FIGURE 4. Zadbimyia costaricensis, male. A: ejaculatory apodeme and parameres, ventral. B: ditto. C: terminalia, ventral. D: fourth flagellomere, lateral. Scale 0.05 mm. ej ap = ejaculatory apodeme, par = paramere, par ap = parameral apodeme, par pr = paramere process.

FIGURE 5. Zadbimyia browni, male. A: gonostylus, ventral. B: ejaculatory apodeme and parameres, ventral. C: terminalia, ventral. D: fourth flagellomere, lateral. Scale 0.05 mm. acc gl dc = accessory gland duct, antGA = anterior portion of gonocoxal apodeme, lat shld = lateral shoulder, vtr em = ventral emargination.

FIGURE 16. Zadbimyia anniae, male. A: gonostylus, ventral. B: fourth flagellomere, lateral, only basal pores of circumfilum shown. C: terminalia, gonostyli omitted, ventral. D: ejaculatory apodeme and parameres, ventral. Scale 0.05 mm.

FIGURE 22. Zadbimyia spinapiscis, male. A: terminalia, ventral. B: fourth flagellomere, lateral, only basal pores of circumfilum shown. C: ejaculatory apodeme and parameres, ventral. Scale 0.05 mm.

FIGURE 23. Zadbimyia inornata, male. A: terminalia, ventral. B: fourth flagellomere, lateral. C: ejaculatory apodeme and parameres, ventral. Scale 0.05 mm.