Sphyracephala brevicornis ( Say, 1817 )

Feijen, Hans R., Feijen, Frida A. A. & Feijen, Cobi, 2025, A revision of the four Afrotropical and Palaearctic Sphyracephala Say (Diptera, Diopsidae) with an illustrated overview of the other five Sphyracephala, ZooKeys 1241, pp. 1-81 : 1-81

Sphyracephala brevicornis ( Say, 1817)

Figs 100 , 105 , 106 , 107 , 108 , 109 , 110–112 , 113–115 , Tables 2 , 3 , 4

Diopsis brevicornis Say, 1817: 23.

Sphyracephala brevicornis (Say): Say 1828: plate LII (unpaginated). Portschinsky 1871: 287 (material from Siberia, misidentification for S. nigrimana); Curran 1934: 358 (in part, figure represents S. subbifasciata); Lavigne 1962: 5 (Lavigne - pers. comm. - later indicated that all data refer to S. subbifasciata, except for 1958 records); Sabrosky 1965: 638 (in part); Steyskal 1972: 13 (in part); Hochberg Stasny 1985: 1; Peterson 1987: 785 (in part); Feijen 1989: 72, figs 5–10, 13–40; Marshall 2017: 419, fig. 9 on p. 510. Up to 1989, authors considered S. subbifasciata as junior synonym of S. brevicornis. Their treatment of Nearctic Sphyracephala could therefore be one of the two species or a mixture.

Achias brevicornis (Say): Wiedemann 1830: 564. Wiedemann received these flies as A. brevicornis, but was convinced that they belonged to Diopsis.

Sphyracephala bicornis (Say): Peterson 1916: 183. Error for S. brevicornis.

Type series.

U. S. A.: holotype, sex unknown, Wissahickon Creek near Philadelphia, Pennsylvania [~ 40°8'55"N, 75°13'14"W, ~ 60 m]. It seems likely that the single type specimen of S. brevicornis has been lost.

Distribution.

South-Eastern corner of Canada, contiguous U. S. A. east of the line Houston-Lincoln (Nebraska) - Grand Forks.

Illustrations.

Feijen (1989) provided drawings of external morphology and genitalia. To this is added a set of photographs (Figs 113 – 118 ) of habitus, head, thorax, wing, fore femur, and abdomen.

Figures

Figure 100. Sphyracephala brevicornis, eye span plotted against body length. Older measurements for S. brevicornis from the 1970 s and 1980 s were also used. These measurements were not elaborated with the required accuracy for allometric studies. However, given the large number of data, the allometric lines obtained could be used, though the R 2 values were rather low. Two data points for S. nigrimana are also presented.

Figure 105. Eye span plotted against body length for males of eight Sphyracephala species. A single data point for S. nigrimana is also shown.

Figure 106. Eye span plotted against body length for females of eight Sphyracephala species. A single data point for S. nigrimana is also shown.

Figure 107. Geometric morphometric PCA analysis of Sphyracephala wing venation patterns. Grey dots represent landmarks that were placed with the aid of straight (dotted) lines through other landmarks (white dots). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figure 108. Hierarchical clustering analysis of principal component scores from the PCA in Fig. 107, using the average clustering method. Branch labels indicate the Approximately Unbiased p-value (AU) and Bootstrap Probability (BP). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figure 109. Hierarchical clustering analysis of principal component scores from the PCA in Fig. 107, using the complete clustering method. Branch labels indicate the Approximately Unbiased p-value (AU) and Bootstrap Probability (BP). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figures 110–112. 110 Cladogram of Sphyracephala species groups according to Feijen (1989) 111 preferred maximum likelihood phylogeny of the Sphyracephalinae, based on molecular analysis (Jackson 2019, supplemental figure 1, in slightly adapted form). Numbers at nodes represent Ultrafast Bootstrap supports 112 revised cladogram of Sphyracephala species groups.

Figures 113–115. Sphyracephala brevicornis, Belmont, U. S. A. 113 ♀, habitus, lateral view 114 ♂, head, anterior view 115 ♀, basiliform prosternum, ventral view. Scale bars: 1 mm (113); 0.2 mm (114, 115).

Figures 116–118. Sphyracephala brevicornis, USA 116 ♀, Lewisburg, PA, wing 117 ♂, Belmont, fore femur, outer view 118 ♀, Philadelphia, abdomen, dorsal view. Scale bars: 0.5 mm (116, 118); 0.2 mm (117).