Cembrotia Gagné, 2013

Gagné, Raymond J., 2013, Four new genera of Nearctic Cecidomyiidae (Diptera) for species previously incorrectly placed, Zootaxa 3701 (2), pp. 148-158 : 148-150

Cembrotia Gagné , new genus

Figs. 1–5

Diagnosis. Adults of Cembrotia can be separated from all other genera of the supertribe by the following combination of characters: C broken immediately posterior to junction with R5; R5 reaching C slightly anterior to wing apex; empodia much longer than tarsal claws; tarsal claws with basal tooth; second through seventh abdominal tergites of both sexes with posterior setae continuous across sclerite and lateral setae present; gonocoxal mediobasal lobe not prominently subdivided into dorsal and ventral lobes, blunt apically; gonostylus bulbous, widest near midlength, completely setulose, without ridges, tapered to narrow tooth; female eighth abdominal tergite one-fourth longer than seventh, divided into two separate, longitudinal sclerites; ovipositor elongate-protrusible, bare dorsally, with scattered setae ventrally and wide, lateral, lightly pigmented dorsolateral sclerite along length of ninth segment subdivided by closely placed, oblique, parallel lines; cerci fused, with many equally long setae, none thickened and blunt-tipped. Third instar larva lack a spatula, a common occurence in Cecidomyiinae that live in close spaces where motion is constrained.

Description. Adult. Head: Eye facets circular, contiguous on ventral half of eye, farther apart dorsally, eye bridge 3–4 facets long. Antenna: scape and pedicel with many setae ventrally and medially; 13–15 flagellomeres; all but last flagellomere with long necks in male, about one-third length of node, without necks in female. Frons with many setae and scales. Labella large, blunt-tipped in frontal view, with 3 to many stout setae. Palpus 4-segmented, segments exceptionally short, about as long as wide, the last two segments together usually no longer than combined length of first two.

Thorax: Scutum with 4 longitudinal rows of setae mixed with some scales, the 2 dorsocentral rows several setae wide anteriorly, narrowing to one seta wide before vanishing shortly before scutellum, the 2 lateral rows 2–3 setae wide mixed with some scales and continuous along length of sclerite. Scutellum with abundant setae and scales laterally. Anepisternum with 0–few scales dorsally; anepimeron setose; pleura otherwise bare. Wing: C broken beyond junction with R5; R5 reaching C slightly anterior to wing apex; M not apparent; CuA forked. Acropod ( Fig. 1 ): claws thick with small, thin, basal tooth; empodia appreciably longer than claws; pulvilli about 1/3 as long as claws.

Male abdomen: First through seventh tergites rectangular, with anterior pair of trichoid sensilla, single to double row of setae along posterior margin but sparse mesally; second to seventh tergites also with several lateral setae and scattered scales; eighth tergite unpigmented posteriorly and medially, with anterior pair of trichoid sensilla, several lateral setae and a few scales medially. Second through seventh sternites rectangular, with single horizontal row of posterior setae on second sternite progressively increasing to three rows on eighth sternite, 2–3 rows of setae mixed with scales in transverse group near midlength, and pair of closely adjacent trichoid sensilla anteriorly. Terminalia ( Figs. 2–3 ): cercus ellipsoid, with a few setae apically and laterally; hypoproct parallel-sided, sides curved ventrally, posterior edge transverse to weakly concave, with pair of subapical and pair of apical setae, otherwise evenly setulose on both surfaces; gonocoxite cylindrical laterally, its mediobasal lobe broad, not subdivided, nearly as long as aedeagus, blunt apically with several setae on raised bases; gonostylus bulbous, without ridges, largest near midlength, tapering to apical tooth, with scattered setae and completely setulose; aedeagus slightly longer than gonocoxal lobes, blunt apically.

Female abdomen ( Figs. 4–5 ): First through seventh tergites quadrate, narrowing gradually beyond fourth; fifth and sixth about 2 times as wide as long; first through sixth tergites with two anterior trichoid sensilla, single row of posterior setae, 1–3 lateral setae, and evenly distributed scales elsewhere; seventh tergite quadrate, with row of posterior setae, no laterals and few scales mesally; pair of pseudosclerites present between seventh and eighth tergite (except in less well-pigmented specimens); eighth tergite narrower, about longer than seventh, divided into two separate longitudinal sclerites, each with trichoid sensillum anteriorly, and several setae posteriorly. Second to seventh sternites as for male; eighth sternite apparent only by presence of trichoid sensilla and occasionally some sclerotization surrounding them. Ovipositor elongate, protrusible, bare dorsally, with scattered setae ventrally, and wide, lightly pigmented dorsolateral sclerite along length of ninth segment subdivided by closely placed, oblique, parallel lines; cerci fused, cylindrical, covered with many, equally long setae, none thickened and blunt tipped; hypoproct tapered to apex, with 2 distal setae.

Larva. Third instar: Ovoid. Integument spiculose. Head short, hemispherical, cephalic apodemes shorter than head capsule, antennae less than twice as long as wide. Spatula absent. Papillae with very short setae; lateral papillae in two groups of three on each side of midline; 6 terminal papillae.

Type species, Janetiella coloradensis Felt.

Material examined (all taken from galls in needles of Pinus edulis Engelm. (Pinaceae) in USA). Syntypes of Janetiella coloradensis , 3 ♀ and larva, Denver, Colorado, 1914, E. Bethel; 3 ♂, 3 ♀, Fort Collins, Colorado, VII– 13–1973, J.W. Brewer; 5 ♂, 5 ♀, 3 larvae, same locality, V–25–1981, C. Gillet; 2 ♂, 2 ♀, 3 larvae, I–17–1970, J.W. Brewer; ♂, ♀, larva, Tucson, Arizona, VI–30–1914, W.D. Edmonston. Janetiella sp. near coloradensis Felt of Brewer 1971: 5 ♂, 5 ♀, 3 larvae, Fort Collins, Colorado, VII–13–1973, J.W. Brewer. All specimens are in the National Museum of Natural History, Smithsonian Institution, Washington, DC; the syntypes of J. coloradensis are also presently there on long-term loan but are the property of the New York State Museum in Albany.

Etymology. The name Cembrotia combines Cembroides, the name for the section of Pinus to which the known host plants belong, but shortened here to “Cembro, with the suffix “tia to indicate the host association of the included species. The gender is feminine.

Remarks. This new genus includes several species, only one of which has been described. Cembrotia coloradensis (Felt 1912) , new combination, causes a needle-shortening gall on Pinus edulis Engelm. (Pinaceae) in Colorado (Gillet and Brewer 1983) and California (Russo 2006). An undescribed species was referred to by Brewer (1971) as Janetiella sp. near coloradensis , also on P. edulis . I am aware of additional species from Colorado received from W. Brewer that also form needle-shortening galls on P. e d u l i s and Pinus monophylla Torr. & Frém. in Colorado and Arizona (Gagné 1989), and one other (as Janetiella sp.) on P. edulis in California (Russo 2006).

Cembrotia differs from the two other new genera on conifers described here by its toothed tarsal claws, very short palpi, each segment barely longer than broad, the undivided mediobasal lobes of the gonocoxites, the bulbous and completely setulose gonostyli, the presence of a pair of pseudosclerites between the seventh and eighth tergites and pair of eighth sternite trichoid sensilla. Cupressatia and Strobilotia have untoothed tarsal claws, longer palpal segments, the distalmost at least twice as long as wide, the mediobasal gonocoxal lobe subdivided into a rounded dorsal lobe and a longer, more tapered ventral lobe, and the gonostylus is foreshortened, glabrous and ridged. Cupressatia is distinct from Strobilotia for its continuous row or rows of tergal posterior setae on the tergites, the short, undivided female eighth tergite and the presence in the third instar of a spatula. Strobilotia has the tergal posterior setae largely interrupted mesally, the female eighth tergite three times as long as the seventh, and no larval spatula. All three new genera on conifers have empodia that are appreciably longer than the claws. While this serves as an excellent key character, empodial length is not necessarily synapomorphic. It is interesting that long empodia are present in most conifer-feeding gall midges, both Lasiopteridi and Cecidomyiidi, no matter their relationship. A rare exception is Dasineura balsamicola (Lintner) , an inquiline in galls of Paradiplosis tumifex Gagné on Abies (Osgood and Gagné 1978) . Were it not for a few notable exceptions of gall midges not associated with conifers that have empodia that are longer than the claws, e.g., Semudobia on birch (Roskam 1977), one could expect that any gall midge with long empodia was associated with a conifer.

Figures

FIGURES 1 – 5. Cembrotia coloradensis. 1, Acropod. 2 – 3, Male terminalia: 2, only one gonopod shown (dorsal), 3, aedeagus with gonocoxal mediobasal lobes and apodeme (dorsal). 4 – 5, Female postabdomen: 4, posterior end of sixth segment to fused cerci (dorsolateral), 5, fused cerci and hypoproct, detail (lateral).