Dixa repanda Peters

Moulton, John K., 2018, Rediscovery of Dixa repanda Peters and description of its putative sister species, Dixa falcata sp. nov., from the south-central United States (Diptera: Dixidae), Zootaxa 4459 (1), pp. 171-178: 175-177

publication ID

https://doi.org/10.11646/zootaxa.4459.1.8

publication LSID

lsid:zoobank.org:pub:C01AD7DE-E3EC-4266-8538-726A07B95178

persistent identifier

http://treatment.plazi.org/id/6B6E87F7-F342-FFD2-4CA7-1F69FBDCFC19

treatment provided by

Plazi

scientific name

Dixa repanda Peters
status

 

Dixa repanda Peters 

( Figs 4 View Figure , 6, 8, 10 View Figure )

Dixa repanda Peters in Peters & Cook, 1966: 249  .

Type material examined. HOLOTYPE ♂ (card pointed) labeled: “Goodhue Co.[unty], Minn.[esota]/ May 21 1937 ”; “D.G. Denning/ Collector”. “ HOLOTYPE / Dixa  / repanda  / Peters/ USNMAbout USNM No. 67271 [red-trimmed label]” ( USNMAbout USNM). Terminalia: Not examined, presumed lost.

Additional material examined. USA: Arkansas: STONE COUNTY, Ozark NF, Blanchard Sprs Crk below source [N35°57′31.4″ W92°10′43.1″, 166 m], 21.v.1991, B.J. Sinclair (1♂, CNCAbout CNC)GoogleMaps  . Iowa: JEFFERSON COUNTY, Black Bridge Spr, S of Waupeton , N42°39′44.2″ W90°52′55.7″, 195 m, 17.ix.2009, J.K. Moulton (13♂, 8♀)GoogleMaps  . Illinois: MONROE COUNTY, Bicklein Cave Spr, 8 km W of Waterloo, T2S R10W SE1/4SE1/4 Sec 19, Waterloo 7.5’ Quadrangle [N42°29′22.5″ W92°29′51.8″, 308 m], 14.xii.1996, J. Krejca et al (1♂, UWS)GoogleMaps  . Indiana: CRAWFORD COUNTY, Hoosier NF, Trickling str @ Hemlock Cliffs [N38°16′30.2″ W86°32′17.5″, 214 m], 19.v.1991, B.J. Sinclair (5♂, CNCAbout CNC)GoogleMaps  . PERRY COUNTY, Hoosier NF, Trib Middle Deer Crk @ CR10, N37°59′11.0″ W86°37′23.9″, 140 m, 4.x.2009, J.K. Moulton (2L*)GoogleMaps  . Kansas: RILEY COUNTY, Manhattan, “ Hibernating ” under rock [N39°10′13.1″ W96°39′01.7″], 13.xii.1930, H.L. Culer (1♂, USNMAbout USNM)GoogleMaps  . Missouri: PHELPS COUNTY, Meramac Spr, 12.9 km S St James [N37°57′12.8″ W91°31′57.8″, 261 m], 28.iv.1956, P.J. Spangler (1♂, USNMAbout USNM)GoogleMaps  . ST FRANCOIS COUNTY, St Francois SP, stream beside old schoolhouse, N37°59′21.6″ W90°30′49.7″, 238 m, 30.iv.2009, J.K. Moulton (2♂)GoogleMaps  . STONE COUNTY, Crane Crk @ Crane City Park , N36°54′08.2″ W93°34′25.0″, 339 m, 30.iv.2009, J.K. Moulton (1♀)GoogleMaps  . Oklahoma: JOHNSTON COUNTY, Viola Sprs @ McIntosh Rd , ex emergent vegetation, N34°22′46.5″ W96°31′36.5″, 241 m, 25.iii.2010, E.A. Bergey (1♂ & 3♀)GoogleMaps  . PONTOTOC COUNTY, unnamed spr ex D169 Rd, 4 km S of Fittstown , N34°34′22.7″ W96°38′51.0″, 313 m, 25.iii.2010, E.A. Bergey (1♂, 1♀)GoogleMaps  .

Diagnosis. The less strongly setose, curved, non-tapered, banana-like gonostylus coupled with obliterated cercus and larger, more protruding basal gonocoxal lobe distinguishes this species from all other Nearctic species, including D. falcata  sp. nov.

Redescription. Differing from D. falcata  sp. nov. as follows. Male. Wing length (n =10) 2.5–3.4 mm (avg=3.1). Terminalia ( Figs 4 View Figure , 6, 8, 10 View Figure ): Gonostylus slightly shorter, ca. 2.5X longer than greatest height, considerably less tapered apically and with shorter and sparser setae on medial surface. Basal gonocoxal lobe appearing more protrusive from dorsal gonocoxal margin in lateral view.

Female. Wing length (n =8) 2.7–3.7 mm (avg=3.3). Indistinguishable from those of D. falcata  sp. nov. and several other similarly colored, related species.

Distribution and bionomics. Attempts by the author to collect material from near the type locality in Illinois (Havana) and paratype locality (environs of Rochester, MN) were unfruitful. Streams in and around Havana, IL, are heavily degraded and inaccessible due to co-opting for agricultural production. New collections of this species broadened its known range to the east to include southern portions of Indiana and Illinois and southwesterly into Arkansas, Missouri and Oklahoma ( Fig. 14). It likely also occurs in the Arkansas Ozarks as well as northern Kentucky. Dixa repanda  appears to be multivoltine and likely typically overwinters as eggs, although one female examined taken near Manhattan, Kansas, was observed under a rock in mid-December. Larvae mature as early as March in the southern portion of the range. This species occurs in spring-fed streams ( Fig. 13 View Figure ) very similar to those preferred by D. falcata  sp. nov., and they likely co-inhabit streams somewhere in the Ozark/Quachita region.

Remarks. Several issues hampered the author’s elucidation of the identity of this species. Firstly, the illustration of the male terminalia in Peters & Cook (1966, fig. 47) in lateral view does not accurately reflect the shape of the gonostylus. Secondly, the slide-mounted terminalia of the male holotype could not be located in the USNMAbout USNM and are presumed lost. Thirdly, the two paratype males could not be located and may also be lost. Lastly, attempts to collect streams in the environs of Havana, Illinois, the type locality, were fruitless as the streams were largely inaccessible and ones that were observed look extremely degraded. It was not until examining a male specimen taken near Manhattan, Kansas, that was identified as D. repanda  by T.M. Peters, that the association between my material and the holotype was synched. The absence of any other Dixa  species, besides the easily discernable D. fluvica Peters  , taken in the study area also reinforces this decision.

USNM

Smithsonian Institution, National Museum of Natural History

CNC

Canadian National Collection of Insects, Arachnids, and Nematodes

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Dixidae

Genus

Dixa

Loc

Dixa repanda Peters

Moulton, John K. 2018

2018
Loc

Dixa repanda Peters in Peters & Cook, 1966 : 249

: 249