Massalongia Kieffer, 1897

Elsayed, Ayman Khamis, Skuhrava, Marcela, Ohta, Kazuki, Yoshida, Satoshi & Tokuda, Makoto, 2020, Revision of the birch-associated genus Massalongia (Diptera, Cecidomyiidae), with description of a new species from Japan and a taxonomic key to worldwide species, ZooKeys 958, pp. 1-27 : 1

Genus Massalongia Kieffer, 1897

Massalongia Kieffer, 1897: 12. Type species, Hormomyia rubra Kieffer by original designation.

Apagodiplosis Gagné, 1973: 862. Type species, Oligotrophus papyriferae Gagné, comb. nov.

Diagnosis.

Massalongia differs from other genera of the supertribe Cecidomyiidi in the following combination of characters: antennal flagellomeres are cylindrical in both sexes; male flagellomeres possess three sets of short-looped circumfila that appear interconnected at least in some flagellomeres of each specimen; the reduced abdominal setation; the unmodified female tergite VIII; the presence of dorsal pigmentation on the protrusible part of ovipositor; the massive gonocoxites and mediobasal lobes; the habit of mature larvae to pupate in the soil inside hyaline bottle-shaped cocoons. The following diagnosis lists the attributes shared by known species and can serve as a checklist for future species descriptions.

Description.

Adults. Head. Eye bridge 5-6 facets long; facets rounded. Occiput without dorsal protuberance (Fig. 4 ). Mouthparts (Fig. 5 ): labrum with short setae and no microtrichia; hypopharynx microtrichose; labellum ellipsoid, with stout setae laterally; palpus 3-segmented, consecutively longer, microtrichose, with scattered setae and no scales. Antenna (Figs 6-9 ): scape conical, pedicel rounded; flagellomeres cylindrical in both sexes, successive flagellomeres diminishing gradually in length; flagellomeres I-II connate. Female flagellomeres with 2 sets of interconnected circumfila. Male flagellomeres with 3 sets of short-looped circumfila, some flagellomeres with interconnected circumfila.

Thorax (Figs 10 , 11 ). Wing hyaline; Rs present but rudimentary; R4+5 curved toward apex, joining C posteriad of wing apex; C not broken after the conjunction with R4+5. Acromere: claws untoothed, bent beyond midlength; empodia longer than claws. Scutum with 4 rows of numerous setae. Anepimeron with setae. Anepisternum and katepisternum bare.

Female abdomen (Figs 12 - 15 ). Tergites I-VII entire, rectangular, without scales, with anterior pair of trichoid sensilla; tergites I-VI with 1 row of posterior setae; tergite VII with 1-2 rows of posterior setae; tergite VIII unpigmented, differentiated from remainder of tergum only by anterior pair of trichoid sensilla, without scales and setae. Sternites II-VI with scattered setae near midlength, 1 posterior row of setae; sternites III-VII with anteromedial pair of trichoid sensilla; sternite VIII unpigmented, without anterior pair of trichoid sensilla, with scattered setae posteriorly. Ovipositor: protrusible portion with stiff dorsal sclerite, scattered setae ventrally and few setae dorsally; cerci separate, bilaterally flattened, with 2 slightly thickened sensory setae at apex; hypoproct with 2 apical setae.

Male abdomen. Tergites I-VII as in female; tergite VIII short, sclerotized only anteriorly, with anterior pair of trichoid sensilla located on the sclerotized part. Sternites II-VI as in female; sternite VII with anteromedial pair of trichoid sensilla, scattered setae near midlength and 1-2 posterior rows of setae; sternite VIII short, with pair of trichoid sensilla placed anterolaterally and 2-3 posterior rows of setae. Terminalia (Figs 16-18 ): Gonostylus covered mostly with microtrichia and setae dorsally and ventrally, with comb-like denticles; gonocoxite robust, massive, with enlarged mediobasal lobes and microtichose; hypoproct elongate, constricted after midlength, without setae dorsally, with setae posteroventrally.

Pupa (Figs 19-20 ). Exuviae not pigmented except antennal horns and prothoracic spiracles. Two asetose and 2 setose cephalic papillae present. Prothoracic spiracle long, slightly curved. Abdominal spiracles present on segments II-VI. Abdominal segments I-VII each with 6 dorsal papillae. Dorsal and lateral parts of abdominal segments covered evenly with pointed spinules, diminishing gradually in length and width, except on posterior third.

Mature larva. Spatula bilobed (Fig. 22 ) or absent (Fig. 39 ). Ventral papillar pattern basic for Cecidomyiidi ( Gagné 1989). One asetose anal papilla present on each side of anal opening; other 2 asetose papillae situated posterolaterally, each on separate plaque (Fig. 23 ). Six dorsal papillae present on thoracic segments and abdominal segments I-VII; 2 setose dorsal papillae present on abdominal segment VIII.

Remarks.

Comparisons with other possibly related genera revealed that the Nearctic genus Apagodiplosis Gagné, which contains a single species, A. papyriferae ( Gagné), fits the definition of Massalongia ( Gagné, 1973). No differences were found between the two genera ( Gagné 1967, 1973). Thus, we synonymize Apagodiplosis under Massalongia and M. papyriferae ( Gagné) is a new combination.

Figures

Figures 4 - 11. Massalongia nakamuratetsui sp. nov. 4 head 5 ventral view of mouthparts 6 female antenna 7 male antenna 8 dorsal view of female flagellomere V. 9 dorsal view of male flagellomere V. 10 wing 11 tarsomere V and acromere. Scale bars: 50 µm.

Figures 12 - 13. Terminal part of female abdomen of Massalongia nakamuratetsui sp. nov. 12 dorso-lateral view 13 ventro-lateral view. Scale bars: 50 µm.

Figures 14 - 18. Massalongia nakamuratetsui sp. nov. 14 terminal part of female abdomen (arrow indicate the dorsal sclerite on the protrusible portion) 15 protrusible portion of ovipositor 16 male terminalia 17 ventral view of gonostylus 18 ventral view of male hypoproct. Scale bars: 50 µm.

Figures 19 - 21. Pupa of Massalongia nakamuratetsui sp. nov. 19 ventral view of head 20 prothoracic spiracle 21 dorsal view of terminal part of abdomen (arrows indicate dorsal spines). Scale bars: 50 µm.

Figures 22 - 24. Larva of Massalongia nakamuratetsui sp. nov. 22 spatula 23 ventral view of terminal abdominal segments 24 dorsal view of terminal abdominal segments. Scale bars: 50 µm.

Figures 39 - 41. Larva of Massalongia bachmaieri. 39 ventral view of prothoracic segment 40 ventral view of terminal abdominal segments 41 dorsal view of terminal abdominal segments. Scale bars: 50 µm.