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Volume 27.1
January–April 2024
Full table of contents
ISSN: 1094-8074, web version;
1935-3952, print version
Recent Research Articles
See all articles in 27.1 January-April 2024
See all articles in 26.3 September-December 2023
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Dale E. Greenwalt. Department of Paleobiology, National Museum of Natural History MRC 121, Smithsonian Institution, 10th & Constitution Ave. NW, Washington, D.C. 20013-7012. GreenwaltD@si.edu
Dale Greenwalt received his BA from the University of Minnesota, an MSc from Bemidji State University and his PhD from Iowa State University. He was an Assistant Professor of Biochemistry at San Jose State University before moving to the biotechnology industry, working at Human Genome Sciences and Poietic Technologies, the latter at which he was Director of Research. He is currently a Research Collaborator at the Smithsonian's National Museum of Natural History where he is establishing a collection of fossil insects from the Eocene Kishenehn Formation in northwestern Montana.
John K. Moulton.The University of Tennessee, Entomology and Plant Pathology Department, 432 Biotechnology Bldg., 2505 E. J. Chapman Drive, Knoxville, TN 37996-4560. jmoulton@utk.edu
John K. Moulton, Ph.D., is currently Associate Professor of Entomology at the University of Tennessee in Knoxville, TN. In his career as a research entomologist he has conducted fieldwork in Australia and throughout the Nearctic Region, published over 55 peer-reviewed publications, and described 14 species to date. Among his many interests are morphological and molecular systematics of the fly families Dixidae, Simuliidae, and Tachinidae and the collembolan genus Pogonognathellus.
FIGURE 1. Habitus of Dixa intacta, holotype. Scale bar equals 3 mm.
FIGURE 2. Morphological features of Dixa intacta. 1, Antennae with individual flagellomeres delineated; 2, Dorsal aspect of the thorax. Scale bars equal 0.5 mm for both figures.
FIGURE 3. Line drawings of wings. 1, Dixella intacta; 2, D. eomarginata; 3, D. curvistyla. Wing venation is from McAlpine (1981). Scale bar equals 1 mm.
FIGURE 4. Tarsal claw teeth of the Kishenehn Dixella. 1, Dixella intacta left metatarsal claw; 2, D. curvistyla left metatarsal claw; 3, D. spinilobata right metatarsal claw. Arrows point to teeth. Scale bars equals 50 μm.
FIGURE 5. The terminalia of Dixa intacta. 1, Posterior portion of abdomen including the spermatheca; 2, Cerci. Scale bars equal 0.5 mm (1) and 0.05 mm (2).
FIGURE 6. Habitus of Dixella eomarginata, holotype. Scale bar equals 3 mm.
FIGURE 7. Morphological features of Dixa eomarginata. 1, Wing with an emarginate posterior margin (arrowhead); arrows denote an apparent false vein posterior to vein M. 2, Terminalia. Scale bars equal 1.0 mm (1) and 0.25 mm (2).
FIGURE 8. Habitus of Dixella curvistyla, holotype. Scale bar equals 3 mm.
FIGURE 9. Morphological features of Dixella curvistyla. 1, Head and antennae; 2, Terminalia. The arrow points to the apical lobe of the gonocoxite. Scale bars equal 0.5 mm (1) and 0.2 mm (2).
FIGURE 10. Habitus of Dixella spinilobata, holotype. Scale bar equals 3 mm.
FIGURE 11. Morphological features of Dixella spinilobata. 1, Photograph of the terminalia; spiniform apical lobe marked with an arrow; 2, Line drawing of a partial reconstruction of the right portion of the terminalia (dorsal view). Scale bar equals 0.25 mm.
FIGURE 12. Intraspecific wing venation pattern variability in Dixidae. 1-2, Wings from two different individuals of Dixella nova (USNM01193745, USNM01193785, ♀, ♂, respectively; NY). 3-4, Wings from two different individuals of Dixa terna (USNM01193791, USNM01193792, ♂, ♂, respectively; PA & VA). 5-6, Wings from two different individuals of Dixa rhathyme (USNM01193798, USNM01193868, ?, ♀, respectively; CA). 7-8, Wings from two different individuals of Dixella obscura (USNM01193908, USNM01193974, ?, ♀, respectively; AZ & AK). Collection localities are in parentheses. Arrows and arrowheads denote specific points of variation. Abbreviations: AK = Alaska, AZ = Arizona, CA = California, NY = New York, PA = Pennsylvania, VA = Virginia, USA.
TABLE 1. Extant genera of the family Dixidae.
Name | Number of species | Geographical distribution |
Asiodixa Papp et al., 2006 | 2 | Thailand |
Dixa Meigen, 1818 | 106 | World-wide except Antarctica |
Dixella Dyar & Shannon, 1924 | 64 | World-wide except Antarctica |
Meringodixa Nowell, 1951 | 1 | North America |
Mesodixa Belkin, Heinemann & Page, 1970 | 1 | Jamaica |
Metadixa Peters and Savary, 1994 | 1 | Philippines |
Neodixa Tonnoir, 1924 | 1 | New Zealand |
Nothodixa Edwards, 1930 | 10 | Australia, Chile & New Zealand |
TABLE 2. Fossils of the family Dixidae.
Name | Age | Lithology | Formation/Location | Reference |
Dixidae incertae sedis | Oligocene | Marl | Bouldnor Formation, U. K. | Cockerell, 1921 |
(Dixa priscula Cockerell, 1921. Nomen dubium) | ||||
Dixidae incertae sedis | Paleocene/ Eocene | Clayey diatomite | The Fur Formation, Denmark | Ansorge, 1992 |
(Dixa cimbrica Ansorge, 1992. Nomen dubium ) | ||||
Dixa minuta | Late Eocene | Amber | The Baltic region (Europe) | Meunier, 1906 |
Dixa tertiaria | Oligocene | Marl | The d'Aix Formation, France | Meunier, 1915; Theobald, 1937 |
(Dixa hyalipennis Theobald, 1937) | ||||
Dixella distans | Late Eocene | Amber | The Baltic region (Europe) | Hennig, 1966 |
Dixella filiforceps | Late Eocene | Amber | The Baltic region (Europe) | Hennig, 1966 |
Dixella intacta | Middle Eocene | Oil shale | Kishenehn Formation, U.S.A. | Greenwalt & Moulton, 2016* |
Dixella eomarginata | Middle Eocene | Oil shale | Kishenehn Formation, U.S.A. | Greenwalt & Moulton, 2016* |
Dixella spinilobata | Middle Eocene | Oil shale | Kishenehn Formation, U.S.A. | Greenwalt & Moulton, 2016* |
Dixella curvistyla | Middle Eocene | Oil shale | Kishenehn Formation, U.S.A. | Greenwalt & Moulton, 2016* |
Dixella succinea | Late Eocene | Amber | The Baltic region (Europe) | Meunier, 1906 |
Eucorethrina convexa | Late Jurassic | Shale | The Itat Formation, Siberia | Lukashevich, 1996 |
Eucorethrina flexa | Middle Jurassic | Shale | The Itat Formation, Siberia | Kalugina & Kovalev, 1985 |
Eucorethrina westwoodi | Early Cretaceous | Shale | Durlston & Lulworth Formations, U.K. | Lukasevich et al., 2001 |
?Syndixa liasina | Middle Jurrasic | Shale | Dzhil Formation, Kyrgyzstan | Lukashevich, 1996 |
Syndixa mollis | Middle Jurassic | Shale | The Itat Formation, Siberia | Lukashevich, 1996 |
Syndixa sibirica | Early Jurassic | Shale | The Itat Formation, Siberia | Lukashevich, 1996 |
*This study
APPENDIX 1.
Taxa examined in wing venation variability analysis. † denotes an extinct taxon.
Taxon | Reference/Depository |
Asiodixa pura | Papp et al., 2006 |
Asiodixa maculosa | Papp et al., 2006 |
Dixa aliciae | WRBU |
Dixa babai | Takahashi, 1958 |
Dixa brevis | WRBU |
Dixa californica | WRBU |
Dixa camerounensis | WRBU |
Dixa cimbrica† | Ansorge, 1992 |
Dixa clavata | WRBU |
Dixa dilatata | WRBU |
Dixa dyari | WRBU |
Dixa fluvica | WRBU |
Dixa fusca | WRBU |
Dixa hegemonica | WRBU |
Dixa hikosana | Takahashi, 1958 |
Dixa hoffmani | WRBU |
Dixa inextricata | WRBU |
Dixa johannseni | WRBU |
Dixa kaplani | Wagner et al., 1991/1992 |
Dixa kyushuensis | Takahashi, 1958 |
Dixa lobata | WRBU |
Dixa lobatus | WRBU |
Dixa longistyla | Takahashi, 1958 |
Dixa lunata | WRBU |
Dixa maculata | WRBU |
Dixa melanderi | WRBU |
Dixa minuta† | Hennig, 1966 |
Dixa minutiformis | Takahashi, 1958 |
Dixa modesta | Johannsen, 1923 |
Dixa modesto | WRBU |
Dixa naevia | WRBU |
Dixa nebulosa | WRBU |
Dixa neoaliciae | WRBU |
Dixa neohegemonica | WRBU |
Dixa nipponica | Takahashi, 1958 |
Dixa notata | WRBU |
Dixa nova | Peters, 1981 |
Dixa nubilipennis | WRBU |
Dixa obtusa | Takahashi, 1958 |
Dixa orientale | WRBU |
Dixa priscula† | Cockerell, 1921 |
Dixa puberula | Disney, 1975 |
Dixa punctata | Wagner et al., 1991/1992 |
Dixa rathyme | WRBU |
Dixa serrata | WRBU |
Dixa serrifera | WRBU |
Dixa similis | WRBU |
Dixa spiralis | WRBU |
Dixa stuckenbergi | WRBU |
Dixa submaculata | WRBU |
Dixa subobscura | Takahashi, 1958 |
Dixa terna | WRBU |
Dixa tertiaria† | Theobald, 1937 |
Dixa trilineata | Takahashi, 1958 |
Dixa xavia | WRBU |
Dixa yamatona | Takahashi, 1958 |
Dixella aegyptiaca | Wagner et al., 1991/1992 |
Dixella aestivalis | WRBU |
Dixella amphibia | Disney, 1975 |
Dixella attica | Wagner et al., 1991/1992 |
Dixella aurora | WRBU |
Dixella autumnalis | WRBU |
Dixella corensis | Peters, 1992 |
Dixella cornuta | WRBU |
Dixella curvistyla† | This study |
Dixella deltoura | WRBU |
Dixella distans† | Hennig, 1966 |
Dixella eomarginata† | This study |
Dixella fernandezae | Chaverri and Borkent, 2007 |
Dixella filicornis | Disney, 1975 |
Dixella filiforceps† | Hennig, 1966 |
Dixella fraxina | Taber, 2010 |
Dixella fuscifrons | Wagner et al., 1991/1992 |
Dixella fuscinervis | WRBU |
Dixella golanensis | Wagner et al., 1991/1992 |
Dixella hansoni | Chaverri and Borkent, 2007 |
Dixella hernandezi | Chaverri and Borkent, 2007 |
Dixella indiana | Peters and Cook, 1966 |
Dixella intacta† | This study |
Dixella israelis | Wagner et al., 1991/1992 |
Dixella jironi | Chaverri and Borkent, 2007 |
Dixella laeta | Peus, 1936 |
Dixella limai | WRBU |
Dixella lobata | Chaverri and Borkent, 2007 |
Dixella maculata | Chaverri and Borkent, 2007 |
Dixella martini | WRBU |
Dixella neozelandica | Belkin, 1968 |
Dixella nixiae | Peters, 1980 |
Dixella obscura | WRBU |
Dixella pollex | Nowell, 1980 |
Dixella pyrenaica | Peus, 1936 |
Dixella scitula | Belkin et al., 1970 |
Dixella serotina | Disney, 1975 |
Dixella shannoni | Chaverri and Borkent, 2007 |
Dixella solomonis | WRBU |
Dixella spinilobata† | This study |
Dixella succinea† | Hennig, 1966 |
Dixella suzukii | Chaverri and Borkent, 2007 |
Dixella techana | WRBU |
Dixella torrential | WRBU |
Dixella trinitensis | WRBU |
Dixella venezulensis | Chaverri and Borkent, 2007 |
Dixella vespertina | WRBU |
Dixella woodi | Chaverri and Borkent, 2007 |
Eucorethrina convexa† | Lukashevich, 1996 |
Eucorethrina flexa† | Kalugina, 1985, Lukashevich, 1996 |
Eucorethrina westwoodi† | Lukashevich et al., 2001 |
Meringodixa chalonensis | Nowell, 1951 |
Mesodixa biambulacra | Belkin et al., 1970 |
Neodixa minuta | Belkin, 1962 |
Nothodixa campbelli | Belkin, 1968 |
Nothodixa otagensis | Belkin, 1962 |
Nothodixa septentrionalis | Belkin, 1962 |
Nothodixa philpotti | Belkin, 1962 |
Syndixa mollis† | Lukashevich, 1996 |
Syndixa sibirica† | Lukashevich, 1996 |
APPENDIX 2.
Character states used in the analysis of fossil and extant dixid wing venation.
1. Vein Sc apex relative to the origin of Rs: basal [>2X vein width] (0); subbasal [<2X vein width] (1); even (2); subapical [<2X vein width] (3); apical [>2X vein width] (4).
2. Crossvein r-m origin relative to the bifurcation of Rs: basal (0); subbasal [<2X vein width] (1); even (2); subapical [<2X vein width] (3); apical (4).
3. Crossvein m-cu origin relative to the terminus of r-m: basal (0); subbasal [<2X vein width] (1); even (2); subapical [<2X vein width] (3); apical (4).
4. Vein A1 terminus relative to the origin of Rs: basal (0); subbasal [<2X vein width] (1); even (2); subapical [<2X vein width] (3); apical (4).
5. Vein A1 terminus relative to Sc terminus: basal (0); subasal [<2X vein width] (1); even with (2); subapical [<2X vein width] (3); apical (4).
6. Vein A1 terminus relative to the bifurcation of Cu: basal (0); subbasal [<2X vein width] (1); even (2); subapical [<2X vein width] (3); apical (4).
7. Vein R2+3: branched (0); unbranched (1).
8. R2+3 curvature: straight or very slightly arched (0); strongly arched (1).
9. Vein R2+3 branch relative to the bifurcation of M: basal (0); subbasal [<2X vein width] basal (1); even (2); subapical [<2X vein width] (3); apical (4).
10. Vein R1: fused to C far basal (near 3/4 wing length) of wing apex (0); closer to C than R2 and fused near wing apex (1); equidistant to C and R2 and fused near wing apex (2).
11. Vein R2: not fused with R1 (0); fused with R1 (1).
12. Rs: straight (0); sigmoidal (1).
13. Wing length/width: <2.5(0); 2.5 - 3 (1); >3 <4 (2) >4 (3).
APPENDIX 3.
Morphological data matrix (Dixidae wing and venation characters only).
Taxon | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
13 |
Dixa aliciae | 2 | 1 | 2 | 2 | 2 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa babai | 0 | - | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixa brevis | 2 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
Dixa californica | 3 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixa camerounensis | 0 | 4 | 4 | 2 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa clavata | 2 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa dilatata | 0 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 3 | 1 | 0 | 0 | - |
Dixa dyari | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa fluvica | 1 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa fusca | 0 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa hegemonica | 1 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixa hikosana | 0 | - | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixa hoffmani | 0 | 2 | 0 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa inextricata | 2 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa johannseni | 4 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa kaplani | 0 | 2 | 0 | 2 | 4 | 0 | 0 | 1 | 3 | 1 | 0 | 0 | 1 |
Dixa kyushuensis | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa lobata | 4 | 2 | 4 | 4 | 4 | 2 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa lobatus | 2 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa longistyla | 0 | 0 | 4 | 0 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa lunata | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa maculata | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa melanderi | 2 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa minutiformis | 0 | 3 | 4 | 4 | 4 | 2 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixa modesta | 0 | 4 | 4 | 2 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixa modesto | 0 | 4 | 4 | 4 | 3 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa naevia | 2 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa nebulosi | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixa neoaliciae | 0 | 0 | 0 | 4 | 4 | 1 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa neohegemonica | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixa nipponica | 0 | - | 4 | 4 | 0 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa notata | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa nubilipennis | 0 | 4 | 4 | 2 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa obtusa | 0 | - | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixa orientale | 4 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa puberula | 1 | 3 | 4 | 4 | 4 | 1 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Dixa punctata | 0 | 2 | 0 | 2 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 2 |
Dixa rhathyme | 2 | 3 | 4 | 4 | 4 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | - |
Dixa serrata | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa serrifera | 0 | 4 | 4 | 3 | 4 | 0 | 0 | 1 | 3 | 1 | 0 | 0 | - |
Dixa similis | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixa spiralis | 0 | 0 | 4 | 2 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa stuckenbergi | 0 | 0 | 4 | 1 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa submaculata | 1 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa subobscura | 0 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixa terna | 0 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixa trilineata | 0 | - | 4 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa xavia | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixa yamatona | 0 | - | 4 | 4 | 4 | 1 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Dixa priscula | 0 | 2 | 0 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixa cimbrica | 1 | 4 | 0 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | 0 |
Dixa minuta | 0 | 0 | 2 | - | - | - | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa tertiaria | 0 | 0 | 1 | 3 | 4 | 1 | 0 | 1 | 4 | 1 | 0 | 0 | 2 |
Dixella aegyptiaca | 0 | 1 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 2 |
Dixella aestivalis | 0 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella amphibia | 2 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
Dixella attica | 3 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 0 |
Dixella aurora | 0 | 4 | 3 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella autumnalis | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella corensis | 0 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | - |
Dixella cornuta | 1 | 2 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella deltoura | 0 | 2 | - | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella fernandezae | 0 | 0 | 3 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella filicornis | 0 | 0 | 4 | 4 | 4 | 2 | 0 | 1 | 1 | 1 | 0 | 0 | 0 |
Dixella fraxina | 0 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella fuscifrons | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella fuscinervis | 4 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella golanensis | 2 | 4 | 4 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixella hansoni | 0 | 0 | 2 | 4 | 4 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
Dixella hernandezi | 4 | 4 | 2 | 4 | 3 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
Dixella indiana | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixella israelis | 0 | 4 | 4 | 4 | 4 | 4 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixella jironi | 0 | 2 | 2 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella laeta | 4 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixella limai | 0 | 2 | 0 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella lobata | 0 | 2 | 2 | 4 | 4 | 0 | 0 | 1 | - | 1 | 0 | 0 | 1 |
Dixella maculata | 4 | 2 | 4 | 2 | 0 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Dixella martini | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixella neozelandica | 1 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixella nixiae | 0 | 2 | 1 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Dixa nova | 4 | 3 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 2 |
Dixella obscura | 0 | 4 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella pollex | 0 | 4 | 4 | 0 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Dixella pyrenaica | 0 | 0 | 4 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixella scitula | 2 | 4 | 0 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixella serotina | 0 | 3 | 4 | 4 | 4 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella shannoni | 4 | 0 | 2 | 4 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella solomonis | 2 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | - |
Dixella suzukii | 0 | 2 | 0 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Dixella techana | 0 | 4 | 0 | 4 | 4 | 0 | 0 | 1 | 3 | 1 | 0 | 0 | - |
Dixella torrentia | 0 | 2 | 0 | 4 | 4 | 4 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella trinitensis | 0 | 0 | 4 | 0 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixella venezulensis | 0 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella vespertina | 1 | 3 | 2 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | - |
Dixella woodi | 2 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
Dixella spinilobata | 0 | - | - | - | - | - | 0 | 1 | - | 1 | 0 | 0 | 2 |
Dixella eomarginata | 2 | 3 | 2 | 4 | 4 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
Dixella curvistyla | 0 | 0 | 3 | - | - | - | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
Dixella intacta | 2 | 3 | 2 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
Dixella distans | 0 | 3 | 4 | 4 | 4 | 4 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixella filiforceps | 0 | 2 | 3 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | - |
Dixella succinea | 0 | 2 | 4 | 4 | 4 | 1 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Mesodixa biambulacra | 1 | 2 | 3 | 4 | 4 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Meringodixa chalonensis | 2 | 4 | 4 | 4 | 4 | 1 | 0 | 1 | 2 | 1 | 0 | 0 | 1 |
Neodixa minuta | 0 | 0 | 4 | 4 | 4 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 |
Asiodixa pura | 0 | 0 | 3 | 2 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
Asiodixa maculosa | 0 | 0 | 4 | 0 | 4 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 1 |
Nothodixa campbelli | 0 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 0 |
Nothodixa otagensis | 0 | 0 | 4 | 4 | 4 | 2 | 0 | 1 | 4 | 1 | 0 | 0 | 1 |
Nothodixa septentrionalis | 0 | 0 | 4 | 4 | 4 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 |
Nothodixa philpotti | 0 | 0 | 4 | 0 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 0 | 0 |
Eucorethrina convexa | 4 | 4 | 2 | 4 | 3 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 |
Eucorethrina flexa | 3 | 4 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 1 |
Eucorethrina westwoodi | 4 | 4 | 2 | 4 | 2 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 |
Syndixa mollis | 4 | 4 | 2 | 4 | 3 | 4 | 0 | 0 | 0 | - | 1 | 0 | 0 |
Syndixa sibirica | 4 | 4 | 2 | 4 | 1 | 4 | 0 | 0 | 0 | - | 1 | 0 | 1 |
The first fossil New World Dixidae with a critical discussion of generic definitions
Plain Language Abstract
The dipteran family Dixidae is a small group of 184 extant species of flies. They, along with two other families, are related to mosquitoes but have received little attention from modern taxonomists. The fossil record of the dixids is relatively good with 13 described species. In this study, we describe four additional extinct species from the oil shale of the 46 million-year-old Kishenehn Formation in Montana, including the first females and the only fossil species to be described from the New World. We review the morphological bases of the generic assignments of all extant and extinct dixids and conclude that neither of the two major genera, Dixa and Dixella, can be distinguished by wing venation characters alone. Given that some fossil species of Dixidae consist only of an isolated wing, the generic assignments of these specimens must be re-examined.
Resumen en Español
Los primeros fósiles de Dixidae del Nuevo Mundo con una discusión crítica de las diferenciaciones de los géneros
Se describen cuatro nuevas especies fósiles de la familia de dípteros Dixidae, incluyendo los primeros ejemplares fósiles de hembras de esta familia, provenientes de las lutitas bituminosas del Eoceno Medio de la Formación Kishenehn en el noroeste de Montana. Estas nuevas especies, Dixella intacta sp. nov., D. eomarginata sp. nov., D. spinilobata sp. nov. y D. curvistyla sp. nov., son los primeros fósiles de Dixidae que se describen del Nuevo Mundo. Se revisa críticamente el cuerpo de carácteres morfológicos usados hasta ahora para todas las asignaciones a nivel taxonómico de género de los Dixidae existentes y extintos, y se presentan nuevos datos sobre la variabilidad del patrón de venación alar en Dixidae actuales. Se concluye que es imposible distinguir entre los adultos de los dos géneros principales, Dixa y Dixella, a partir únicamente de la venación alar. Debido a la falta de rasgos distintivos, los nombres de las dos especies cenozoicas que consisten únicamente un ala aislada en cada caso, Dixa priscula y D. cimbrica, se declaran nomina dubia y los fósiles se asignan a Dixidae incertae sedis.
Palabras clave: Dixidae; insecto fósil eoceno; Formación Kishenehn; venación; nuevas especies
Traducción: Enrique Peñalver (Sociedad Española de Paleontología)
Résumé en Français
Les premiers fossiles de Dixidae du Nouveau Monde et une révision des définitions des genres
Quatre nouvelles espèces fossiles de la famille de diptères Dixidae, incluant notamment les premiers spécimens fossiles de femelles de cette famille, sont décrites dans les schistes bitumineux de l'Éocène moyen de la formation de Kishenehn, nord-ouest du Montana. Ces nouvelles espèces, Dixella intacta sp. nov., D. eomarginata sp. nov., D. spinilobata sp. nov., et D. curvistyla sp. nov., sont les premières espèces fossiles de Dixidae décrites dans le Nouveau Monde. Les définitions morphologiques de tous les genres de dixidés actuels et éteints sont révisées, et de nouvelles données sur la variabilité des schémas de nervation des ailes des Dixidae actuels sont présentées. Il est conclu qu'il est impossible de distinguer les adultes des deux genres principaux, Dixa et Dixella, en se basant uniquement sur la nervation des ailes. Étant donné le manque de caractères diagnostiques, les noms des deux espèces cénozoïques qui sont basées sur des ailes isolées, Dixa priscula et Dixa cimbrica, sont déclarées nomina dubia et les fossiles sont attribués à Dixidae incertae sedis.
Mots-clés : Dixidae : fossiles d'insectes éocènes ; formation de Kishenehn ; nervation ; nouvelle espèce
Translator: Antoine Souron
Deutsche Zusammenfassung
Das erste Dixidae-Fossil aus der neuen Welt mit einer kritischen Diskussion der Gattungsdefinition
Vier neue fossile Arten der Dipteren-Familie Dixidae, mit den ersten weiblichen Stücken in dieser Familie, werden aus den mitteleozänen Ölschiefern der Kishenehn-Formation von Nordwest-Montana beschrieben. Diese neuen Arten, Dixella intacta sp. nov., D. eomarginata sp. nov., D. spinilobata sp. nov. und D. curvistyla sp. nov., sind die ersten beschriebenen Dixidae-Fossilien aus der neuen Welt. Es wird die morphologische Basis aller Gattungszuordungen der heutigen und ausgestorbenen Dixiden kritisch überprüft und neue Daten zur Flügelnervatur-Variabilität bei heutigen Dixidae werden vorgelegt. Es wurde der Schluss gezogen, dass es unmöglich ist, zwischen den Adulten der zwei großen Gattungen Dixa und Dixella, nur aufgrund der Flügelnervatur zu unterscheiden. Da es an Unterscheidungsmerkmalen fehlt, werden die Namen der zwei känozoischen Arten, die nur aus einem Flügel bestehen, Dixa priscula und D. cimbrica, zu nomina dubia erklärt und die Fossilien werden den Dixidae incertae sedis zugeschrieben. .
Schlüsselwörter: Dixidae; eozäne Insektenfossilien; Kishenehn Formation; Nervatur; neue Art
Translator: Eva Gebauer
Arabic
Translator: Ashraf M.T. Elewa
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Review: The Princeton Field Guide to Mesozoic Sea Reptiles
The Princeton Field Guide to Mesozoic Sea Reptiles
Article number: 26.1.1R
April 2023