Microcercis laytoni, Foster, 2024

Foster, George A., 2024, Revision of Nearctic Microcercis Beschovski (Diptera: Chloropidae), with Synonymy of Incertella Sabrosky, Zootaxa 5481 (4), pp. 401-439 : 419-421

Microcercis laytoni new species

http://zoobank.org:act: 2744DC3D-D06B-4CFA-ABBA-B065F111439A

( Fig. 23 )

Diagnosis.—Ocellar triangle entirely yellow; vertex and occiput gray orange; frons yellow; postpedicel brown dorsally around base of arista or more, remainder yellow; prosternum yellow; scutum entirely gray; postpronotal lobe mostly yellow, may be gray along dorsal margin; notopleuron gray; pleuron mostly to entirely gray, tomentose except small spot below the anterior spiracle, posterior surface of the katepisternum and meron polished; legs mostly gray except femora yellow at distal tips; tibial organ yellowish; abdominal tergites uniformly brown with narrow yellow posterior margins.

Description.—Body length; female: unknown; male: 1.07–1.21mm.

Head: Ocellar triangle evenly grey tomentose; vertex and occiput grey tomentose; frons yellow; scape and pedicel brown, postpedicel mostly brown dorsally, ventral half or less yellow; arista black, pubescent; face, palps, gena, and clypeus yellow tomentose; prementum polished brown, labellum yellow; gena to eye ratio 0.20.

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

Thorax: Prosternum yellow; prescutum polished black; postpronotal lobe yellow on ventral half or more; notopleuron gray; scutum entirely grey tomentose; pleuron mostly grey tomentose except small spot below the anterior spiracle, posterior surface of the katepisternum and meron polished; mediotergite entirely grey tomentose; scutellum gray tomentose; subscutellum yellowish tomentose; wing length 0.95–1.24 mm, hyaline, costal ratios 0.34:0.29:0.16; legs nearly entirely grey tomentose except femora yellowish at distal tips; tarsi yellow except distal tarsomere black or brown; all femora and tibiae with only light scattered setulae; femoral organ not imaged; tibial organ narrow, yellowish.

Thoracic chaetotaxy: Scapular setae absent; scutal and scutellar setae black.

Abdomen: Abdominal tergites and sternites uniformly brown with posterior margins of tergites yellow. Male terminalia (not imaged due to lack of males, cerci and surstyli appear very similar to M. bispina and M. dorsata ): epandrium blackish tomentose with many setulae. Female unknown.

Type material.— The holotype male is labeled [white label] “DE: Sussex Co.: Angola / Sally Cove: sweeping beach grasses/ 38°38′54.70″N 75°07′45.64″W / 24–27 August 2021 / GA and AM Foster coll.//[white label] ♂ //[red highlighted] HOLOTYPE/ Microcercis laytoni Foster ♂ / G. A. Foster 2023 // USNMENT 01519365 [inverted white label]”

The holotype is double mounted (0.15mm minuten inserted in a white cube of silicone rubber on a #2 insect pin), is in excellent condition, and is deposited in the USNM.

PARATYPES (4♂, 3♀): DELAWARE. Sussex Co.: Angola, Sally Cove sweeping beach grasses, (38°38′54.70″N 75°07′45.64″W), 24–27 Aug 2021, G. A. and A. M. Foster (1♂; GAF) .

USA. FLORIDA. St. Johns Co.: St. Augustine, 14 June 1979, Amnon Friedberg (2♀; NMNH) .

MISSISSIPPI. Harrison Co.: Pass Christian , 8 June 1917, J. M. Aldrich (2♂; NMNH) .

NEW JERSEY. Ocean Co.: Barnegat , salt marsh Spartina , (39°51′21″N 76°05′19″W), 15 June 2022, William L. Murphy (1♂; GAF) .

SOUTH CAROLINA. Horry Co.: Myrtle Beach , 28 July 1941, A. L. Melander (1♀; NMNH) .

Distribution.—Nearctic: United States (Delaware, Florida, Mississippi, New Jersey, South Carolina).

Discussion.—This species is distinguished from other Microcercis species by the yellow postpronotal lobe and otherwise nearly entirely brownish gray pleuron with two polished spots, one just under the postpronotal lobe and the other on the posterior surface of the katepisternum and the meron which is very similar to M. insularis , from which it clearly differs in the color of the postpronotal lobe and the male genitalia. I examined the cleared male genitalia of one specimen. The images are too poor for publication but I could clearly see that the cerci are diminutive and the surstyli have a smooth distal margin, lacking the prominent projection of M. insularis .

Notes.—I collected this species late in the 2021 season (October) and found few specimens so far. It shares the halophilic habitat with M. infesta , M. trifeminarum and M. insularis .

Etymology.—This species is named in honor of my first grandson, Layton James Arbogast of Baltimore, Maryland. Layton has always shown a great interest in my work and in the natural world.

Figures

FIGURES 23–30. Microcercis and Conioscinella morphology. 23, M. laytoni habitus, lateral view. 24, M.trifeminarum habitus, lateral view. 25, C. ovalis HOLOTYPE habitus, lateral view. 26, M. albipalpis male genitalia, posterior oblique view. 27, M. albipalpis surstylus. 28 M. bispina male genitalia, posterior oblique view. 29, M. dorsata male genitalia, posterior oblique view. 30, M. infesta male genitalia, posterior oblique view.