Microcercis albipalpis (Meigen), 2007

Foster, George A., 2024, Revision of Nearctic Microcercis Beschovski (Diptera: Chloropidae), with Synonymy of Incertella Sabrosky, Zootaxa 5481 (4), pp. 401-439 : 406-408

Microcercis albipalpis (Meigen)

( Figs. 15 , 26, 27 )

Chlorops albipalpis Meigen, 1830: 163 . Type locality: Europe. Deposited Naturhistorisches Museum, Vienna, Austria (NHMW).

Chlorops socius Meigen, 1830: 155 . Type locality: Europe. Deposited NHMW. Synonymy: Duda 1932: 47; Nartshuk 1997: 403.

Oscinis albipalpis . — Zetterstedt 1838: 489, 781 (Lapland).

Oscinis basalis Zetterstedt, 1860: 6441 . Type locality: Illstorp, Skåne, Sweden. Synonymy: Becker 1910: 163; Andersson 1966: 75.

Oscinosoma albipalpis .— Enderlein 1913: 356.

Oscinella albipalpis .— Becker 1910: 163 (Europe).

Conioscinella albipalpis . — Duda 1932: 46 (Europe).

Tropidoscinis albipalpis . — Collin 1946: 136 ( England).

Incertella albipalpis .— Sabrosky 1980: 422; Beschovski 1981: 61 [male genitalia]. Cherian 2002: 15 [femoral organ].

Microcercis albipalpis .— von Tschirnhaus 2007: 131 [new combination]. Deeming & Al-Dhafer 2012: 39 ( Oman).

Oscinella opacifrons Aldrich (unpublished), Sabrosky 1936: 724 [new syn., spms labeled opacifrons in various collections and “ paratypes ” but never published by Aldrich].

Oscinella incerta Becker, 1912: 116 [orig. description: (Type locality, Troy, Idaho. Deposited NMNH)].— Sabrosky 1935 [in key, discussion, compared with bispina , sexual dimorphism, Kansas distrib.].— Sabrosky 1936 [in key, discussion of type material, sr. syn. of opacifrons Aldrich ].— Sabrosky 1965 [N. Am. catalog, distrib.]. NEW SYNONYM

Incertella incerta .— Sabrosky 1980 [placement in Incertella n. gen.].

Diagnosis—Ocellar triangle gray to brown; vertex and occiput gray to black tomentose; postpedicel entirely black; prosternum brown; scutum gray to brown tomentose; postpronotal lobe and notopleuron gray to yellowish, tomentose; pleuron brown, ventral polished area continuous from propleuron to meron; femora and tibiae brown; tibial organ yellow; syntergite 1+2 usually brown, occasionally yellowish; male cerci widely separate, small lobes; surstylus short, parallel sided or widening slightly, distal tip smooth spatulate, slightly angulate dorsally.

Description.—Body length; female: 1.65−1.90 mm; male: 1.28−1.60 mm.

Head: Ocellar triangle evenly gray to brown tomentose; vertex and occiput gray to black tomentose; frons yellow; scape and pedicel dark brown, postpedicel entirely black; arista black, pubescent; face, palps, and gena yellow tomentose; clypeus black; prementum polished brown, labellum light brown; gena to eye ratio 0.22.

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

Thorax: Prosternum usually brown, may be yellow in specimens with lighter legs; prescutum polished brown; scutum mostly brown, evenly grayish tomentose; postpronotal lobe and notopleuron gray to slightly yellowish tomentose, slightly lighter than scutum; pleuron brown to nearly black; polished except anepisternum and anepimeron mostly gray tomentose and katepisternum with a small anterior spot of tomentum; mediotergite mostly polished black, gray tomentose on small lateral areas; scutellum brown, margin yellowish, tomentose; subscutellum yellowish tomentose; wing length 1.32–1.74 mm, hyaline, costal ratios 0.37:0.28:0.15; all coxae usually polished light to dark brown, fore coxa may be light to dark yellowish; all femora and tibiae mostly light to dark brown, yellow on one-fourth to one-third of distal tip; all tarsi yellow except for distal 2 tarsomeres; femoral organ two rows of short warts with flattened setae (as in fig. 9); tibial organ yellow to white.

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

Abdomen: Syntergite 1+2 yellow to brown; remaining tergites evenly brown with narrow yellow posterior margins. Male terminalia (figs. 26, 27): Epandrium brown tomentose with many setulae, male cerci widely separate, small lobes; surstylus short, parallel sided or widening slightly, distal tip smooth spatulate, slightly angulate dorsally. Female terminalia including cerci brown.

Distribution.—Nearctic: Canada (Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Yukon). Mexico (Michoacan). United States (Alaska, Arizona, Colorado, Idaho, Iowa, Ohio, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New Mexico, North Dakota, Oregon, Pennsylvania, South Dakota, Tennessee, Utah, Washington, Wisconsin, Wyoming). Palearctic (“Trans-Palearctic polyzonal species known from the British Isles to Japan ” per Nartshuk et al. 2013). Also in the arctic tundra ( Nartshuk 2005: 246), and Mediterranean and Canary Islands (von Tschirnhaus unpubl.).

Discussion.—This species bears a strong resemblance to M. bispina but lacks the scapular setae present that species. It is otherwise distinguished from the other Nearctic Microcercis species by the mostly brown scutum and pleuron and an overall brownish appearance with the most of the ventral half of the pleuron polished. The notopleuron usually has a slight yellowish cast. This is the only species in the Nearctic with the antennae entirely black.

Biology.—In an attempt to examine Foote’s material from his two studies ( Foote 2004 and 2007), I contacted the Carnegie Museum (Pittsburgh, PA), where most of his material is housed, to try to get a loan of these specimens. Foote had recorded over 200 specimens of the genus. They located only 16 specimens of M. bispina from the 2004 study (see below in Material Examined for M. bispina ) and no other material. Therefore, I am unable to confirm Foote’s rearing records.

Nearly all of the material included in this study was from inland habitats yet, von Tschirnhaus (2007) reports that M. albipalpis is one of four very common chloropids on the salt marshes of the North Frisian coast islands of Mellum and Memmert (the others being Oscinella frit , Oscinimorpha minutissima ( Strobl, 1900) and O. albisetosa ( Duda, 1932)) .

There are just two localities in the material examined in this study which could be salt marsh habitats: Courtenay, Vancouver Island , British Columbia, and Shediac, New Brunswick, Canada.

Discussion of the status of Oscinella opacifrons Aldrich (unpub.).— Sabrosky (1936) stated that there were a type and 34 paratypes (I found 39 in the NMNH collection) of this unpublished species that Sabrosky considered to be I. incerta . My examination confirms Sabrosky’s conclusion. Although the description was never published there are an unknown number of specimens labeled O. opacifrons deposited in other (unspecified) collections. For this reason, I record the NMNH material here for the record.

I have examined 39 specimens with “ O. opacifrons Aldrich PARATYPE ” labels. All are clearly M. albipalpis : CANADA. MANITOBA. Glenboro – South Cypress Municipality: Aweme, 1 Aug 1913, N. Criddle (1♀; NMNH) ; same data, 9 Oct 1915, (1♀; NMNH) ; same data, 2 June 1916, (1♀; NMNH) ; same data, 26 June 1916, (6♀; NMNH) ; Treesbank, 12 June 1915, (6♀; NMNH) ; same data, 25 June 1915, (1♀, 1 empty pin; NMNH) ; same data, swept from grass, 13 July 1915, (4♀; NMNH) ; same data, 23 July 1915, (1♂, 4♀; NMNH) ; same data, 17 Aug 1915, (2♀; NMNH) .

USA.

IDAHO. Latah Co.: Moscow, 8 July 1916, J. M. Aldrich (7♀; NMNH) .

MONTANA. Powder River Co.: Powderville , June 1913, no collector (1♀; NMNH) .

SOUTH DAKOTA. Union Co.: Elk Point , 22 May 1915, C. N. Ainslie (1♀; NMNH) .

WASHINGTON. Whitman Co.: Union Flat , 16 June 1916, no collector (2♀; NMNH) .

Type Material of M. incerta examined.— One female with a type label in NMNH. Becker did not designate a holotype. The specimen is badly shriveled but retains all body parts, however the scutal setae are missing. It is mounted through the venter with a minuten pin affixed to a small off-white card and is oriented in an upright position. It has six labels which are (in order from top to bottom): white label with “Troy Idaho ” typewritten and “VI-14-8” handwritten; white label with “Collection JM Aldrich” typewritten; red label with “COTYPE” typewritten, “No. 49970” handwritten, “ U.S. N.M.” typewritten; white label “ Oscinella incerta Beck cotype” handwritten; white label “Look for holotype I think this is not the type Melander coll’n” all handwritten; white label facing down with “USNMENT barcode 01492506”. Clearly the message to “look for” the holotype is incorrect as there was no single specimen designated as the “type”.

Nine PARATYPES: USA. IDAHO. Bingham Co.: Collins , no date, no collector given, A. L. Melander coll’n (1♂; NMNH) ; Latah Co.: Moscow Mt., 17 June 1904, J. M. Aldrich, A. L. Melander coll’n, (2m [1m labeled “Cotype, 49970]”; NMNH) ; Troy, 14 June 1908, no collector A. L. Melander coll’n (1♂, 2♀; NMNH) .

WASHINGTON. Whitman Co.: Pullman, 9 Aug 1908, no collector given, A. L. Melander coll’n, (2♀; NMNH); Rock Lake , no date, no collector given, A. L. Melander (1♀; NMNH) .

Sabrosky noted that there were 13 paratypes deposited in the NMNH and the Museum of Comparative Zoology , Harvard University. He did not state how many are in each depository. I found just these nine in the NMNH material.

There is one specimen, female, in the NMNH collection from Woods Hole, Massachusetts with a red paratype label that reads “ Oscinella incerta Becker ” PARATYPE. However, Becker stated that his type series were from Washington and Idaho only. In any case, I have determined that this specimen is M. infesta . So, it is neither a paratype, nor M. albipalpis .

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 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.