Smithsonian Contributions to Zoology, number 563, 25 pages, 59 figures, 1 table, 1994.—The New World species of the genus Cyamops Melander, now numbering eight, are revised. Maps, species keys, detailed distribution data and illustrations (scanning electron micrographs and line drawings) are provided to assist in species identification. The following ratios are used in the descriptions (2cf and 29 were measured for each species when available, opposite cases are indicated under the corresponding species description).
ACKNOWLEDGMENTS.-Although this study is primarily based on specimens from the Norwegian Natural History Museum, several others, especially type specimens of the previously described species, were borrowed. As a preface to our revision of the species of New World cyamops, we first characterize the family Periscelididae and the subfamily Stenomicrinae. DISCUSSION.—As a preliminary effort to resolve the phylogenetic relationships within the family Periscelididae, we propose the following hypothetical phylogeny as outlined in the cladogram (Figure 1).
The synapomorphies we discovered and analyzed show that the genus Planinasus is more closely related to the genera of the subfamily Periscelidinae than to Stenomicra and Cyamops. The shape of the sixth tergite (narrow and reduced in length) is another likely synapomorphy for Stenomicra+Cyamops.
The plesiomorphic condition means that the faces of men and women are essentially the same width. This character state is a synapomorphy for the Neotropical species (two species from the Neotropics were analyzed). Some characters are polymorphic in the genera Cyamops and/or Stenomicra, making it impossible to determine their polarity by outgroup comparison alone.
Female abdomen with tergite and sternite of segment 7 fused to form a complete ring. This character occurs in the genera of Periscelidinae, sensu stricto, most species of Cyamops, and all. In Australian species of cyamops (Khoo, 1984), however, the tergite and stemite in this segment are free from each other.
We accept, after strict consideration, the fusion of the seventh tergite and sternite as the general or plesiomorphic condition, which would indicate that the Australasian species are apomorphic for this character. For this character, it is relatively clear that the plesiomorphic condition for the family is two scutellar setae, as in the outgroup. In Stenomicra, as well as in the outgroup, all degrees of sclerotization occur in this cross vein, and it is impossible to know what the plesiomorphic condition is for Cyamops.
Chaetotaxic characters of the head and thorax appear to have evolved independently many times within the family and related groups. Cell T4+S usually completely infuscate, split subapical white spot; middle and hind femora mostly yellow (Mexico. Chiapas) C. Head: Ocular tubercle sparsely microtomentose; frons subshine, moderately microtomentose, with polished area immediately laterad of lateral ocellus; mesophrons deeply concave, velvety black; antenna mostly yellow, with dorsal half and sometimes apex of 1st flagellomere brown; facial region mostly yellow; posterior '/3 of gena mostly brown; labellum and palpus mostly white to light yellow; face in profile shallow and vertically curved, not angular; facial carina shallow and narrow; eye sparse microcetulose.
Mostly yellow; fore coxa pale yellow, with mostly white microtomentum; middle coxa brown on dorsal '/2, whitish microtomentose; middle and hind femora brown on apical '/2-2/.v, apical and sometimes subapical tarsomere of each leg brown;.
5th tergite
7th tergite
6th sternite^M
6th syntergosternite
8th stemite 7th syntergosternite
6th syntergosternite tergite
7th syntergosternite M
Indeed, the shape of the aedeagal apodeme and the right sursty 1 in both species appear to be synapomorphies establishing their sister-group relationship. The depressed part of the fungus of this species is moderately densely microtomentose, appearing like velvet. FIGURES 9-11.—Cyamops imitatus: 9, male tergites 5-7 and epandrium, dorsal aspect; 10, male abdominal segments 4–7 and epandrium, ventral aspect; 11, male internal terminal, posteroventral aspect.
Head: Ocellar tubercle slightly microtomentose; region of frons immediately posterior to ocellar tubercle scarcely microtomentose, this region sometimes extending to level of upper orbital seta; mesophrons velvety brown; antenna mostly yellow, infuscate to brown at dorsum '/2; parafacial and gena mostly yellow to brown in ground color, gena darkening towards occipital region; face brown to dark brown, almost devoid of microtomentum between insertion of antenna and angle of vibration; palpus brown; face not angled; facial carina narrow. Chaetotaxy: Inner fronto-orbital seta slightly weaker and spanning about ]/2 of outer fronto-orbital seta; arista with 8/3 rays, of which the first 2-4 are distinctly bipartite;. Thorax: Anepimeron polished anteriorly; halter mostly yellow, slightly infuscate at base; mesonotum slightly longer than wide; scutellum conical, disc convex.
Legs: Anterior femur continues slightly along the anterior margin and into apical 'A; anterior tibia and tarsus entirely light brown to brown; Wing (Figure 23): mostly darkly stained, cells r, entire and r2+3 mostly hyaline, posterior margin and apex of cell r2+3 dark, posterior part of cell m and slightly celcuate with hyaline area; costal vein ratio I: 0.80 (slide-mounted wing); costal vein II ratio: 2.8-3.4 (slide-mounted wing); wing ratio: 3.0 (sliding wing 3.30). 6th and 7th tergites are not of equal length; 4th and 5th tribes are not the same length; sternites 6-7 with posterior processes simple, margins almost straight (Figure 10).
REMARKS.—This species is represented by a few specimens, and the range of variation is largely unsampled. The individuals available to us can be easily distinguished from their relatives by the presence of a single pair of scutes (lateral) and wing pattern.
Thorax: Anepisternum, anepimeron and catepisternum partly smooth in some specimens; halter white, mostly brown at base; mesonotum slightly longer than wide; scutellum conical, disk shallowly convex. Chaetotaxy: Dorsocentral setae 0+1, subequal in length to scutellar setae; mesonotal setulae small and weak; scutellar seta 2 pairs, basal pair about 3A apical length; anepisternum bare posteriorly. Mostly yellow; para coxa pale yellow, white microtomentose and sometimes infuscate at base; the front femur is sometimes injected anteriorly; coxa medium brown on dorsal l/2, gray microtomentose; mid femur slightly infuscate brown in apical V5-3/4, but completely yellow in some specimens; hind femur slightly infuscate brown on apical V2-3A; apical and sometimes subapical tarsomeres of each leg brown; Spine-like setae 8-9, black, easy to distinguish.
Female: Head: Mesofacial light brown to dark brown, central shiny on lower l/3 of median carina; gena mostly yellow to brown; palpus yellow to brown. TYPE MATERIAL—The holotype female is labeled "Woods Hole 7-7-2 [July 7, 1902] Mass[achusetts]/TYPE Cyamops nebulosa Mel. The holotype is mounted twice (pins on rectangular cardboard), is in good condition, and is deposited in USNM.
REMARKS.—Cyamops nebulosus varies greatly in color, even among specimens from the same locality, and some of the variation appears to be sexually dimorphic. Wing and leg coloration is typically darker in females, although the pattern is inconspicuous in some specimens. Chaetotaxy: Dorsocentral setae 0+1, odd length with 1st scute liar seta; many setulae are present between dorsocentral and acrostic rows in most specimens; setulae of mesonotum well developed, some '/3-'/2 length of dorsocentral seta; scutellar setae 2 pairs, basal pair approx. 2 hours length of the apical; anepistemum setulose posteriorly.
Legs (Figure 35): Mostly yellow; fore coxa pale yellow, whitish microtomentose; middle coxa dark brown on dorsal '/2, grey. Male terminalia as follows (Figure 31): Left surstylus narrow, elongate, gradually tapering to tip; right surstylus shorter but wider, somewhat square although wider basally; hypandric process apparently lacking; ejaculatory apodeme (Figure 32) large, length subequal to combined length of 6th and 7th tergites, with expanded process extended to apex, fan-like;. REMARKS.-The specimens we examined were very uniform in the color pattern of the legs and wing.
Among species that have a setose posterior margin of the anepistemum, this species is most similar to C.
JSF" ; 1
CI^JJHI
REMARKS.—This species is distinguished from congeneric species by the patterned wing, infuscate middle and hind tibiae and characters of the male terminalia, especially the shape of the right surstylus. ETYMOLOGY.—The species epithet, columbianus, recognizes the 500th anniversary of the epic voyage of Christopher Columbus and the country where this species was collected. Dorsocentral setae 0+1, less long than the 1st scutellar seta; scutellar setae 2, the basal pair about 2/3 the length of the apical; mesonotal setulae small; anepistemum glabrous.
REMARKS.-The holotype differs slightly from the other males of the type series in that the halter is mostly yellow and the hind tibia entirely yellowish. Chaetotaxy: Dorsocentral setae 0+1, less long than the 1st scutellar setae; mesonotal setulae not well developed; scutellar setae 2, the basal pair about l/2 the length of the apical; anepisternum setulose posteriorly. Hennig was uncertain about the gender of the holotype because the abdomen was damaged.
The broad face, as shown, is characteristic of females and is probably the sex of the holotype. The phylogenetic classification of Diptera Cyclorrhapha, with special reference to the structure of the male postabdomen. Manuscripts intended for serial publication undergo content review (conducted by the original Smithsonian museums or offices) and are submitted to the Smithsonian Institution Press on Form SI-36, which must demonstrate approval from the appropriate authority designated by the sponsoring organizational unit.
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