Tipula (Trichotipula) fji De Jong, 2019

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 : 5-7

Tipula (Trichotipula) fji De Jong , sp. nov.

Figures 1-3

zoobank.org/ 0CFD881A-D645-4490-99C0-95878A8C7E66

Etymology. The specific epithet (to be pronounced as efyaï) is the Latin genitive case for FJ, which stands for Floris-Jan Muys, a young Dutch researcher.

Holotype. USNM 625687 , deposited in the Department of Paleobiology , National Museum of Natural History (NMNH), Smithsonian Institution, Washington, District of Columbia, USA.

Type horizon. Middle Eocene Coal Creek Member, Kishenehn Formation .

Type locality. Spring site, Middle Fork of the Flathead River (Pinnacle, Montana, USA).

Differential diagnosis. This species of Tipula is distinguished by the short vein Rs, the parallelsided and pentagonal discal cell, the petiolate cell m 1, the length and position of crossvein m-cu, and the shape of the male terminalia.

Description

Adult male (Figure 1.1), body length about 13.5 mm, wing length about 11.5 mm. Specimen preserved in lateral view.

Head. Eyes well-developed, large, almost covering entire head, dorsally with narrow separation. Rostrum shorter than remainder of head, nasus invisible (Figure 2.1). Antenna about 4.5 mm long, longer than head and thorax combined, with elongate scape, pedicel not identifiable, flagellum consisting of 11 cylindrical flagellomeres with enlarged base that carries a set of verticils; flagellomeres becoming shorter towards apex of antenna, apical flagellomere abruptly much shorter than preceding one; most flagellomeres have become separated in fossil. Palp not clearly segmented, apparently densely set with setae (Figure 2.2).

Thorax. Scutum with dorsum moderately curved. Contours of halter indicated, halter about 1.2 mm long.

Wings. Right wing visible (Figure 3.1), although partly broken, apical part of left wing missing. Pterostigma distinct, dark-brown. Microtrichia on membrane visible. Subcosta long, terminating in R 1 just apical of origin of Rs (Figure 3.2). R 1 long, almost straight, terminating in costa near midlength of pterostigma. Rs very short and curved, forking near proximad side of pterostigma. R 2+3+4 short, forking into R 2+3 and the long R 4 at distad end of pterostigma (Figure 3.3). R 4 almost straight towards wing margin. Base of R 5 aligned with crossvein r-m; long apical section of R 5 slightly curved. M forking into short basal sections of M 1+2 and M 3+4. Discal cell with anterior and posterior margins almost parallel-sided, discal cell pentago- nal. M 1+2 forming petiole apicad of discal cell, then forks into a gradually widening cell m 1 towards wing margin. M 3 curves with anteriorly concave bow towards wing margin. M 4 fuses with crossvein m-cu for a short distance near proximal part of discal cell and from there curves with an anteriorly concave arch towards wing margin. Crossvein mcu strong and distinctly longer than Rs. CuA upturned and slightly angled at point of contact with crossvein m-cu; apical section of crossvein CuA rather abruptly curved just before wing margin. False vein immediately posterior to CuA present. CuP gradually deviating from CuA from wing base towards wing margin. A 1 long, slightly sinuous. Anal area of wing well-developed.

Legs. Left legs partly preserved, left foreleg almost complete. Femora and tibiae darkened at extreme tips. No tibial spurs identifiable. Apical tarsomere of foreleg with claw carrying a basal tooth (Figure 1.5).

Abdomen and genitalia. Abdomen made up of rather short segments. Male outer and inner genitalia partly visible (Figure 1.3). Posterior margin of tergite nine with a pair of lateral bulbous extensions that are ventrally set with dark spines; area between the lateral extensions U-shaped emarginate and (ventro-?) medially blackish, sclerotized; black spines along (ventral side of) posterior margin. A pair of blackish-brown gonostyles visible with broad base and slender, somewhat sinuous anterior part that ends in a narrow point; a bundle of thick black, curved setae on dorsal margin. Broad and dark-brown aedeagus clearly visible through integument, runs anterior from ill-defined sperm pump in segment seven to segment three and from there loops back to aedeagal guide in terminal segment (Figure 1.2).

Allotype. Female unknown.

Syncompressions. Coprolite (1).

Remarks

Tipulidae s.str. currently include 38 recent genera and 4,294 species and subspecies; the genus Tipula comprises 40 recent subgenera with 2,634 species and subspecies ( Oosterbroek, 2018). The higher-level classification of the Tipulidae does not necessarily reflect phylogenetic relationships within the family and is in need of revision. Over 100 fossil species are described in Tipulidae , most of them are classified in Tipula sensu lato. The few fossil species that have been assigned to a subgenus of Tipula include T. (Electrotipula) pinetorum Alexander, 1931 ( Alexander, 1931a) , T. (Platytipula) anatolica Kania and Nel, 2013 , T. (Tipula) oligocenica Kania and Nel 2013 , and T. (Trichotipula) paicheleri Kania and Nel, 2013 . Electrotipula Alexander, 1931 ( Alexander, 1931a) is the only described extinct subgenus of Tipula .

The present fossil is placed in the genus Tipula because of its relatively small size, the presence of simple flagellomeres with a whorl of verticils at their enlarged bases (Figure 2.2), the long Sc ending apical of the origin of Rs, the petiolate cell m 1 and the fusion of M 4 with m-cu near the proximal part of the discal cell. It is provisionally placed in the subgenus Trichotipula because of the short vein Rs, the shape of the discal cell (Figure 3.1), the shape and armament of the posterior margin of tergite nine and the shape and sclerotization of the inner gonostylus. The inner gonostylus and the posterior margin of tergite nine are reminiscent of that of the type species of Trichotipula , T. oropezoides (cf. Alexander, 1965, figure 31). The exceptionaly well-preserved aedeagus may suggest that this particular cranefly was teneral and the posteclosion period too short to have allowed cuticular sclerotization.

Trichotipula includes 46 recent species, of which 34 are known from the Nearctic region; eight species are recorded from the Neotropical region, four from the East Palaearctic and one from the Oriental region; one species occurs in both the Nearctic and Neotropical regions. Most, but not all, Trichotipula species have at least some macrotrichia on the membrane of the wingtip; in the present fossil, microtrichia can be observed quite clearly, but macrotrichia are absent.

The fossil species from the late Oligocene of Turkey classified by Kania and Nel (2013) in Trichotipula does not belong to this subgenus, or even to the genus Tipula . The very short vein Rs, the sessile cell m 1 and the position of crossvein mcu proximal of the discal cell indicate that it belongs to the genus Nephrotoma Meigen, 1803 . For these reasons, the species paicheleri is formally transferred to the genus Nephrotoma as Nephrotoma paicheleri (new combination).

Figures

FIGURE 1. Tipula (Trichotipula) fji sp. nov., USNM 625687, male. 1, Habitus; 2, Posterior portion of the abdomen showing aedeagus; 3, Terminalia; 4, Halter; 5, tarsal claws. The arrows point to the front tarsal claw (left) and the terminal tarsomere of either the middle or back leg (right). Scale bars equal 10.0 mm (1), 2.0 mm (2) and 0.5 mm (3-5), respectively.

FIGURE 2. Tipula (Trichotipula) fji sp. nov., USNM 625687. 1, Head. Arrow denotes palpus; 2, Antennae. Arrows denote boundaries between basal flagellomeres, double arrows point to verticils at the base of the terminal flagellomere. Scale bars equal 1.0 mm (1) and 0.5 mm (2).

FIGURE 3. Tipula (Trichotipula) fji sp. nov., USNM 625687. 1, The apical half of the right wing; 2, Detail of vein Sc. The arrow denotes the terminus of Sc, the arrowhead points to a dislocation of a portion of Rs; 3, Detail of anterior radial veins. The arrows point to R1 and the second abscissa of R2 (left and right respectively) and the arrowhead denotes the first abscissa of R2. Scale bars equals 1.0 mm (1), 0.3 mm (2) and 0.5 mm (3).