Cladochaeta arthrostyla, Grimaldi, David A. & Nguyen, Tran, 1999

Grimaldi, David A. & Nguyen, Tran, 1999, Monograph on the spittlebug flies, genus Cladochaeta (Diptera, Drosophilidae, Cladochaetini), Bulletin of the American Museum of Natural History 241, pp. 1-316 : 171-172

Cladochaeta arthrostyla , new species

Figures 94, 96, 98

DIAGNOSIS: Head broad, frons mostly velvety blue-black; cheek very deep; most of thorax and part of pleura dark brown; wings hyaline; male genitalia very distinctive; aedeagus sclerotized, long, pendulent, with tip curved up; surstylus unique, 2-segmented, distal segment with numerous, fine plumose haris, each with 3 branches. Female terminalia distinctive, as described below.

Description: head: Relatively short and long, with a long sloping front. Eyes with sparse, fine, very short pile; lower hind margin of eye with slight indentation seen in lateral view. Antenna with pedicel ochre medially, brown laterally; flagellomere I brown; arista with 3 dorsal branches and 1 ventral one (perhaps the ventral branch of apical fork). Frons long, sloping, quite wide; posterodorsal two-thirds blue-black, velvety; anterior third ochre yellow (entirely blue-black in the female specimen). Frontal-orbital setae: Proclinate orbitals approximately equal in size to posterior reclinates; anterior reclinate orbitals very small, ca. 0.2 X size of proclinates (and about twice the size of frontal-orbital setulae), immediately lateral to proclinates. Ocellar setae slightly shorter than orbitals; postocellars small, ca. 0.4X length of ocellar setae. Dorsal half of face light brown (dark brown in female), ventral half whitish (silvery in female), slightly protruding. Face of moderate width (FW/HW = 0.32 [N = 2]). Cheeks deep, white (silvery in female)(cD/ED = 0.17). Proboscis and palp light yellow; gena and postocciput dark brown.

THORAX: Notum, scutellum, and postnotum dark brown; pleura mostly dark brown, except for katepisternum (mostly ochre) (entirely dark in female). Anterior dorsocentrals ca. 0.6X length of posterior dorsocentrals; post. dorsocentrals closer to scutellum than to ant. dorsocentrals. Acrostichals in 6 uneven rows; acrostichal setula immediately anterior to ant. dorsocentral seta, and prescutellar acrostichals not enlarged. Anterior scutellars parallel; posterior scutellars slightly cruciate. Postpronotal lobe with 1 large seta, no trace of ventral one. Legs entirely light yellow in male (brown in female); forefemur with ventrolateral row of 3 larger setae; 3 larger dorsolateral setae. Wing hyaline, without even diffuse clouds of infuscation on x-veins. Vein R 2+3 straight; apex of R 2+3 gradually meeting costal vein. Veins R 4+5 and M parallel, but both gently curved. Crossvein dm-cu straight. Wing tip slightly pointed, not rounded. Halter light yellow in male, contrasting with dark brown thorax and tergites (entirely light brown in female).

ABDOMEN: All tergites black-brown. Female terminalia reduced, but distinctive; apical tergite very thin, without bridge beneath epi-/hypoproct; apical sternite completely divided into pair of widely separated narrow lobes (apices of each with ca. 10 minute setulae); narrow, tonguelike sclerite lies vertically between sternal and tergal lobes; most parts of terminalia sclerotized. Male genitalia: Cercus with ventrolateral margin flat. Ventrolateral halves of epandrium long, narrow, gradually tapered apicad, each with row of ca. 12 short, stiff setae. Aedeagus heavily sclerotized, smooth (slightly wrinkled); long and pendulous, extends from ventral margin of cercus to ventral margin of epandrium; tip is curved up. Aedeagal apodeme lightly sclerotized, funnel-shaped. Surstylus 2-segmented; basal lobe with numerous fine setulae and small medial lobe; apical lobe slightly larger, with numerous fine setae that are 3-branched. Hypandrium and gonopods lightly sclerotized. Hypandrium with squared anterior margin and deep ventral keel. Gonopods deep, laterally flattened. Apical sternites not examined.

TYPES: Holotype, Male: COSTA RICA: San Jose, Zurqui de Moravia , 1600 m, VII/ 92, P. Hanson, Malaise trap (dissected, no. 283 ) . Paratype: Female, same data as holotype (dissected, no. 284 ) . Both specimens in the AMNH.

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OTHER MATERIAL EXAMINED: Known only from the 2 type specimens.

ETYMOLOGY: from arthro (jointed) and styla, in reference to the 2-segmented surstyli.

DISCUSSION: On the basis of the very unusual feature of 3-branched setae on the surstylus, this species would apparently be closely related to C. dolichofrons . Male genitalia of the 2 species are quite similar overall. C. dolichofrons is known only from Trinidad

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