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The first fossil New World Dixidae with a critical discussion of generic definitions

Dale E. Greenwalt and John K. Moulton

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

 

 

FIGURE 1. Habitus of Dixa intacta, holotype. Scale bar equals 3 mm.

figure1

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.

figure2

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.

figure3

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.

figure4a

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).

figure5

FIGURE 6. Habitus of Dixella eomarginata, holotype. Scale bar equals 3 mm.

figure6

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).

figure7

FIGURE 8. Habitus of Dixella curvistyla, holotype. Scale bar equals 3 mm.

figure8

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).

figure9

FIGURE 10. Habitus of Dixella spinilobata, holotype. Scale bar equals 3 mm.

figure10

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.

figure11

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.

figure12

 

 

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
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
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
 

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

 

 

 

greenwaltDale E. Greenwalt. Department of Paleobiology, National Museum of Natural History MRC 121, Smithsonian Institution, 10th & Constitution Ave. NW, Washington, D.C. 20013-7012. This email address is being protected from spambots. You need JavaScript enabled to view it.

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.

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moultonJohn K. Moulton.The University of Tennessee, Entomology and Plant Pathology Department, 432 Biotechnology Bldg., 2505 E. J. Chapman Drive, Knoxville, TN 37996-4560. This email address is being protected from spambots. You need JavaScript enabled to view it.

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.