Microcercis johanni, Foster, 2024

Foster, George A., 2024, Revision of Nearctic Microcercis Beschovski (Diptera: Chloropidae), with Synonymy of Incertella Sabrosky, Zootaxa 5481 (4), pp. 401-439 : 418-419

Microcercis johanni new species

http://zoobank.org:act: B95BE9ED-AC9D-4FFB-A6FC-BA811BAEB6E2

( Fig. 21 , 32 )

Diagnosis.—Ocellar triangle yellow except ocellar tubercle brown to black; vertex yellow; occiput gray to black; frons yellow; postpedicel black dorsally, yellow ventrally; prosternum bright yellow; scutum ground color yellow, with four variously distinct brighter yellow vittae; postpronotal lobe and notopleuron yellow; pleuron mostly yellow with light brown areas, ventral polished area continuous from propleuron to meron; coxae yellow, femora yellow to light brown, tibiae all yellow to brown, the hind tibia often with a central brown spot; tibial organ bright yellow; abdominal tergites brown with narrow yellow posterior margins; surstylus short, parallel sided with a slight posterior curvature, distal tip squared, angulate.

Description.—Body length; female: 1.43–1.68 mm; male: 1.30 mm.

Head: Ocellar triangle yellow tomentose, ocellar tubercle brown to black; vertex yellow, tomentose; occiput brown to black, tomentose; frons yellow; scape and pedicel yellow, postpedicel black dorsally, yellow ventrally; arista black, short pubescent; face, palps, gena and clypeus bright yellow tomentose; prementum and labellum light brown; gena to eye ratio 0.22.

Cephalic chaetotaxy: Fronto-orbital setae brown; interfrontal setae brown; ocellar setae black, erect; postocellar setae black; outer vertical setae black; inner vertical setae black; postocular setae black; vibrissae yellow; subgenal setae yellow.

Thorax: Prosternum bright yellow; prescutum polished brown to black; scutum with whitish tomentum on yellow ground color with four brighter yellow vittae, vittae sometimes faint; postpronotal lobe yellow; notopleuron yellow; pleuron mostly yellow with light brown areas, ventral polished area continuous from propleuron to meron; mediotergite polished black; scutellum light brown centrally with yellow margin, whitish tomentum; wing length 1.20–1.62 mm, hyaline, costal ratios 0.47:0.34:0.18; coxae yellow, femora often entirely yellow, occasionally darker yellow to brownish, sometimes hind femur with a brown patch ventrally, tibiae may all be yellow or with hind tibia with a brown patch dorsally, tarsi sometimes brown; femoral organ not imaged; tibial organ bright yellow lighter than surrounding tibia.

Thoracic chaetotaxy: Scapular setae absent; scutum and scutellum with yellow to brown setae and setulae.

Abdomen: Tergites brown with yellow posterior margin; sternites yellow; Male terminalia (fig. 32); specimen is uncleared due to the paucity of material): epandrium grey tomentose; cercus not imaged; surstylus parallel sided with a slight posterior curvature, distal tip squared, angulate. Female cerci brown.

Type material.— The HOLOTYPE male is labeled [white label] CALIFORNIA / Inyo Co. Big Pine 4000’ 9 Sept. 1965 M. S. Mulla //[white label] ♂ //[red highlighted] HOLOTYPE/ Microcercis johanni G. A. Foster 2023 ♂ // [inverted white label] USNMENT 01519360 .

The holotype is double mounted on a white paper point, is in good condition, and is deposited in the NMNH.

PARATYPES, (3♂, 5♀; NMNH): UNITED STATES. CALIFORNIA. Inyo Co.: Big Pine , 4000’, 9 Sep 1965 , M. S. Mulla (1♂, 1♀; NMNH) .

FLORIDA. Alachua Co.: Gainesville, 29 Apr 1937, L. J. Bottimer (1♀; NMNH); Pinellas Co. : Clearwater, 15 Sept 1976, G. C. Steyskal (2♀; NMNH) .

KANSAS. Riley Co.: Keats , 4 mi. S, 8 May 1932, C. W. Sabrosky (1♀; NMNH) .

SOUTH CAROLINA. Pickens Co.: Central , 34.71930 -82.77310, no date, (1m [head missing], 1♀), M. Ferro .

Distribution.— United States.(California, Florida, Kansas, South Carolina)

Discussion.—Externally this species is nearly identical to Conioscinella ovalis and is easily mistaken for that species.

The two species share the often pronounced but sometimes faint yellow vittae on the scutum. This species differs from C. ovalis in having shorter, somewhat less dense, microtrichiae of the eye, a shorter head that is slightly longer than high. The gena of C. ovalis is wider (about 0.30 times of the eye height), the postpedicel is entirely yellow whereas in M. johanni it is brown to black dorsally, and the black spot on the ocellar tubercle is oval, extending slightly from the tubercle anteriorly into the ocellar triangle. The male genitalia differ in that the male surstylus of the C. ovalis species is longer and spatulate and the cercus is long and prominant, where in M. johanni the surstylus is much shorter spatulate with an angulate distal tip and the cercus appears to be small and weak.

M. johanni is also similar in appearance to M. minor but differs in often having brown to black areas on the ventral margin of the anepimeron, the anterior margin of the anepisternum and sometimes a dark spot on the ventral portion of the katepisternum. The pleuron of M. minor varies from evenly yellow to having very light grey tomentum on the anepimeron and anepisternum. It is important to note that pleural and scutal color patterns can vary, which is typically the case with the Chloropidae . Some specimens barely show the scutal vittae while in others they are distinct. They are absent in M. minor . The pleural markings vary from light yellow and barely discernable to darker and obvious.

Taxonomic Note. —I examined all the specimens in the NMNH collection that were in trays labeled as “ Incertella ovalis (Adams) ” and that is when I discovered the trays included two species, one clearly a Conioscinella and the other one was a new species of Microcercis , described here. The Field Museum of Natural History very kindly sent me the holotype of ovalis and I have confirmed it to be Conioscinella .

Etymology.—The name johanni is a genitive patronym honoring my son, Johann Walter Foster. Johann has always been supportive of my work and provides a lot of humor while so doing.

Figures

FIGURES 15–22. Microcercis morphology. 15, M. albipalpis habitus, lateral view. 16, M. bispina habitus, lateral view. 17, M. dorsata habitus, lateral view. 18, M. infesta habitus, lateral view. 19, M. insularis habitus, lateral view. 20, M. minor habitus, lateral view. 21, M. johanni habitus, lateral view. 22, M. murphyi habitus, lateral view.

FIGURES 31–38. Microcercis and Conioscinella morphology. 31, M. insularis male genitalia, posterior view. 32, M. johanni male genitalia, posterior oblique view. 33, M. minor male genitalia, posterior view. 34, M. minor male genitalia, lateral oblique view. 35, M. murphyi male genitalia, posterior oblique view. 36, M. murphyi male genitalia, lateral oblique view. 37 M. trifeminarum male genitalia, posterior oblique view. 38, C. ovalis male genitalia, posterior oblique view.