Cyttaromyia fuscula Cockerell, 1921

Dale E. Greenwalt, Daniel J. Bickel, Peter H. Kerr, Gregory R. Curler, Brian V. Brown, Herman de Jong, Scott J. Fitzgerald, Torsten Dikow, Michal Tkoč, Christian Kehlmaier & Dalton De Souza Amorim, 2019, Diptera of the middle Eocene Kishenehn Formation. I. Documenting of diversity at the family level, Paleontologia Electronica 22 (2), No. 50, pp. 1-56 : 12

Cyttaromyia fuscula Cockerell, 1921 ( Cockerell, 1921a, Brodo, 1967)

Figure 7

Asilopsis fusculus Cockerell, 1921 ( Cockerell, 1921a)

Asilopsis fuscula Cockerell, 1921 ( Evenhuis, 1994)

Material examined. Holotype, wing only. USNM

66572 (NMNH; examined).

Type horizon. Middle Eocene, Green River For-

mation.

Type locality. White River , Colorado, USA

Redescription

This specimen consists of a single wing (Figure 7.1-2). The shape of what can be interpreted as R 2+3+4 and R 1, the shape and size of the discal cell, the position of what appears to be M 1, and the shape of cell m 2, which narrows toward the wing margin, indicate that this is a representative of Cylindrotomidae . Scudder (1877) described Cyttaromyia fenestrata from White River, but C. fenestrata has a shorter and apically much wider discal cell, and a very wide cell m 3 compared to C. fuscula . The short section between the first forking of vein M and the position where crossvein m-cu touches the discal cell in C. fusculus differs from the other known Cyttaromyia species; Cyttaromyia fuscula appears to be a distinct species.

Remarks

Originally assigned to Asilidae by Cockerell

(1921a), Asilopsis fusculus was discussed as possibly a member of Asilinae or Laphriinae or its own new subfamily Asilopsinae . Hull (1962) discussed the fossil and stated “... the ultimate interpretation of Asilopsis Cockerell must rest upon the presence or absence of a proboscis and the character of the pretarsus. Without further material and for the reasons given above, I reject a subfamily based upon this fly.” The specimen was subsequently assigned to Tipulidae by Brodo (1967). Twenty years later, Brown (1988), in a review of fossil Cyttaromyia , relied on the input of Curtis Sabrosky and Aubrey Scarbrough who stated “We believe it is a primitive asilid ... and not at all tipuloid.” However, neither Sabrosky nor Scarbrough, who were Brachycera specialists, appear to have been well-acquainted with the diversity of crane flies. Brodo (1967) followed the North American concept of “ Tipulidae ” in which Tipulidae s.l. includes Tipulidae s.str. (as Tipulinae ), Cylindrotominae , Limoniinae and Pediciinae ; the rest of the world treats these four taxa as families. We believe that this specimen represents neither Tipulidae s.str. nor Limoniidae ; the only other crane fly possibility other than Cylindrotomidae would be Pediciidae (based on what in that case would be R 4+5), but then the shape of R 1, R 2 and R 3 would be very unusual, the discal cell much too large and its shape atypical, and the number of M veins would be 'incorrect' for Pediciidae . With the caveat that the specimen is poorly preserved, we propose that wing venation is similar to that of Cylindrotomidae : Cyttaromyia .

Figures

FIGURE 7. Cyttaromyia fuscula Cockerell, 1921 (new combination), USNM 66572. 1, Wing. Arrow points to a defect in the wing where the distal portion of the wing has shifted anteriorly relative to the basal portion causing an upwards curving of the basal portion of Rs; 2, Line drawing of the wing. Scale bar equals 3.0 mm (1).