Peters & Cook, 1966 : 241
Garrett, 1924 : 6
The true identity of Dixa modesta Johannsen (Diptera: Dixidae) resolved: synonymy of Dixa similis Johannsen, designation of the Dixa ubiquita species group, and description of three new eastern Nearctic species
Moulton, John K.
Zootaxa
2017
4216
3
247
260
9HYNR
[151,344,1481,1507]
Insecta
Dixidae
Dixa
Animalia
Diptera
9
256
Arthropoda
species
vockerothi
sp. nov.
Dixa brevis Peters & Cook, 1966: 241, not Garrett, 1924: 6(misidentification of northeastern North American specimens).
Type material. HOLOTYPE, ♂ labeled: “Old Chelsea/ Que. 5.xi.1958/ J.R. Vockeroth”; “ Dixa brevis/ Garrett/ Det. T.M. Peters 1964”; “HOLOTYPE/ Dixa/ vockerothi/ J.K. Moulton [red label]” (CNC). PARATYPES: Old Chelsea, 5.xi.1958, J.R. Vockeroth (10♂; CNC); Same data, except 15.x.1958, J.R. Vockeroth (10♂; CNC). Additional material examined. CANADA: NS: Grande Anse R, Cape Breton Highlands NP, 8–10.vii.1984, I.M. Smith( 1♂, CNC); Kentville, 6.viii.1958, J.R. Vockeroth( 14♂; CNC); Lone Shieling, swept along fast rocky stream, 11.vii.1983, J.R. Vockeroth( 2♂, 2♀; CNC). ON: Normandale, 42°42′ 80°19′, 21.v.1956, J.R. Vockeroth( 1♂, CNC); Sterling, 14.x.1956, J.R. Vockeroth( 2♂, CNC); Ottawa, 30.ix.1956, J.R. Vockeroth( 1♂, CNC); Ottawa, Hog′s Back, 16.x.1947, G.E. Shewell( 2♂, CNC). QC: Eardley, 18.x.1956, J.R. Vockeroth( 2♂, CNC); Gatineau Park, Mackenzie King Falls@ Waterfall Tr, N45°28′41.08″ W75°51′02.98″, ex. above falls, 24.vi.2009, B.J. Sinclair( 2♀, CNC); King Mtn, sm str, 16.xi.2011, B.J. Sinclair( 1♂, CNC); Lac Philippe[Gatineau Park], 45° 37′N76°W, 22.viii.1959, J.R. Vockeroth( 1♂, CNC); Old Chelsea, Mulvihill Brookat Mountain Rd, in one moderately dense swarm 6–8′ over stream, 5.xi.1958, J.R. Vockeroth( 22♂, 1♀, CNC: ethanol); Old Chelsea, 5.xi.1958, J.R. Vockeroth( 21♂, CNC); Old Chelsea, 15.x.1958, J.R. Vockeroth( 42♂, CNC); Old Chelsea, 5.ix.1958, C.H. Mann( 1♂, CNC); Old Chelsea, 22.vii.1956, J.R. Vockeroth( 1♂, CNC); Mt. Orford, 29.viii., 9.ix.1937, G.E. Shewell( 2♂, CNC). USA: NC: HAYWOOD COUNTY, Woodfin Cascade, Blue Ridge Parkway NP, N35°27′08.30″ W83°06′10.6″, 16.vii.2006, J.K. Moulton& G.R. Curler( 2♂, 1L, ANSP); same locality, 24.vii.2011, JKM ( 1♀, ANSP). NY: CATTARAUGUS COUNTY, Stoddard Hollow, 1720–1880 ft, 42°4′N W78°45′, 10.viii.1961, D.L. Deonier/ J.L. Laffoon( 10♂, 2♀, ISIC).
Diagnosis. This species can be distinguished from D. ubiquita sp. nov.and D. elkmontensis sp. nov.by the following characters: Morphological. Basal gonocoxal lobe with apex more digitiform and dorsally directed ( Fig. 18vs. 12, 15), creating more conspicuously concave horizontal margin, most noticeable in terminal view ( Fig. 20vs. 14, 17). Anterior lobe of SES acute apically, with thin, strap-like, connection to ventral apodeme of proctiger acutely angled; distal lobe of SES narrow, lip-like in lateral view ( Fig. 18). Apex of gonostylus not strongly twisted ca. 90° medially, most obvious in ventral view ( Fig. 19). Molecular. Within the 66 nucleotides (22 codons) shown ( Fig. 35) a thymine at position 46 (vs cytosine), an adenine at position 51 (vs. guanine), and a guanine at position 54 (vs. cytosine) serve to distinguish this species from the other two. Within the encompassing amplified fragment of BZF, D. vockerothi sp. nov.is 6.1% divergent from D. ubiquita sp. nov.and 9.1% divergent from D. elkmontensis sp. nov.(JK Moulton, unpublished).
Description. Male. Same as D. ubiquita sp. nov., except as follows: Winglength ( n=10) 3.8–4.1 (avg=4.0) mm. Terminalia( Figs 18–20): Basal gonocoxal lobe narrowed, less than half as broad as gonocoxite depth, with apex more digitiform and dorsally directed, with ventral margin straight to slightly convex ( Fig. 18). Gonostylus with apex straight, not twisted ca. 90° medially, most obvious in ventral view ( Fig. 19). Anterior lobe of SES rounded apically, with connection to 9T and ventral apodeme of proctiger broader; distal lobe of SES narrow, liplike in lateral view ( Fig. 18). Female. Wing length ( n=7) 4.4–4.9 (avg=4.6) mm. Not reliably distinguishable from D. ubiquita sp. nov.or D. elkmontensis sp. nov.
Etymology.Named in honor of Dr. Richard (Dick) Vockeroth, who collected numerous adults of this species, including the typeseries, from several localities in and around the Gatineau area and elsewhere in eastern Canada.
Distribution. Dixa vockerothi sp. nov.appears to be the most northerly distributed of the three members of this species group ( Fig. 34). It is confirmed from numerous localities in the Gatineau Hills region of Quebec, a few sites in Nova Scotia, one site in the Alleghany Mountains of Pennsylvania, and one site in the Southern Appalachian Highlands of western North Carolina.
Remarks. Dixa vockerothiis found in high gradient, rapidly flowing streams 3–5 min width with waterfalls, often stair-cased ones ( Figs 32, 33). It occurs with D. ubiquita sp. nov.in Woodfin Cascades in western NC, and no other dixid associations are known.
1423743198
1984-07-08
1984-07-10
1984-07-08
CNC
Grande Anse R & Cape Breton Highlands NP & I. M. Smith
Canada
CANADA
9
256
1
1
1423743214
[423,996,1799,1824]
1958-08-06
CNC
J. R. Vockeroth
Canada
Kentville
9
256
14
14
1423743207
1983-07-11
CNC
J. R. Vockeroth
Canada
Lone Shieling
9
256
4
2
2
1423743211
1956-05-21
CNC
J. R. Vockeroth
Canada
Normandale
9
256
1
1
1423743200
[302,858,1871,1896]
1956-10-14
CNC
J. R. Vockeroth
Canada
Sterling
9
256
2
2
1423743208
[875,1432,1871,1896]
1956-09-30
CNC
J. R. Vockeroth
Canada
Ottawa
9
256
1
1
1423743217
[151,817,1907,1932]
1947-10-16
CNC
G. E. Shewell
Canada
Back
Ottawa
Hog
9
256
2
2
1423743218
[830,1432,1907,1932]
1956-10-18
CNC
J. R. Vockeroth
Canada
Eardley
9
256
2
2
1423743203
2009-06-24
CNC
B. J. Sinclair
Canada
Waterfall Tr
45.478077
Gatineau Park
1
-75.85082
Mackenzie King Falls
9
256
2
2
1423743197
[435,1045,1979,2004]
2011-11-16
CNC
B. J. Sinclair
Canada
King Mtn
9
256
1
1
1423743206
1959-08-22
CNC
J. R. Vockeroth
Canada
10
257
45.616665
Lac Philippe
9
256
1
1
1423743219
1958-11-05
CNC
J. R. Vockeroth
Canada
Mountain Rd
Old Chelsea
Mulvihill Brook
10
257
44
1
43
1423743209
[632,1266,223,248]
1958-10-15
CNC
J. R. Vockeroth
Canada
Old Chelsea
10
257
42
42
1423743199
1958-09-05
CNC
C. H. Mann
Canada
Old Chelsea
10
257
1
1
1423743216
[566,1188,260,285]
1956-07-22
CNC
J. R. Vockeroth
Canada
Old Chelsea
10
257
1
1
1423743215
29. viii., 9. ix. 1937
CNC
G. E. Shewell
Canada
Mt. Orford
10
257
2
2
1423743210
2006-07-16
HAYWOOD, COUNTY, ANSP
Blue Ridge Parkway NP & J. K. Moulton & G. R. Curler
United States of America
35.452305
Woodfin Cascade
1
-83.10294
10
257
2
2
1423743201
2011-07-24
ANSP
Blue Ridge Parkway NP & J. K. Moulton & G. R. Curler
United States of America
35.452305
Woodfin Cascade
1
-83.10294
10
257
1
1
1423743220
1961-08-10
CATTARAUGUS, COUNTY, ISIC
D. L. Deonier & J. L. Laffoon
United States of America
549
42.066666
Stoddard Hollow
1152
-78.75
10
257
12
2
10