The scorpionfly (Mecoptera) family Bittacidae are known from the Upper Triassic (Riek Reference Riek1955) and their peak diversity occurred in the Jurassic – 26 genera (Handlirsch Reference Handlirsch1906–1908, Reference Handlirsch1939; Martynov Reference Martynov1927; Carpenter Reference Carpenter1928, Reference Carpenter1954, Reference Carpenter1955; Tillyard Reference Tan and Hua1933; Bode Reference Bode1953; Riek Reference Riek1955; Willmann Reference Wang, Shih and Ren1978, 1987, 1989; Sukatcheva Reference Sukatsheva and Rasnitsyn1990; Ansorge Reference Ansorge1993, Reference Ansorge1996; Novokshonov Reference Novokshonov1993a, Reference Novokshonovb, Reference Novokshonov1996, Reference Novokshonov1997a, Reference Novokshonovb; Ren Reference Ren1993, Reference Ren1997; Petrulevičius Reference Petrulevičius1998, Reference Petrulevičius2001a, Reference Petrulevičiusb, Reference Petrulevičius2003; Bechly & Schweigert Reference Bechly and Schweigert2000; Petrulevičius & Martins-Neto Reference Petrulevičius and Martins-Neto2001; Krzemiński Reference Krzemiński2007; Petrulevičius et al. Reference Petrulevičius, Huang and Ren2007; Li et al. Reference Li, Ren and Shih2008; Li & Ren Reference Li and Ren2009; Yang et al. Reference Willmann2012; Wang et al. Reference Villagomez, Contreras-Ramos and Marquez-López2014; Liu et al. 2014, 2016). At the end of Jurassic and the beginning of the Cretaceous, a strong decrease in the diversity of hangingflies was observed (Kopeć et al. Reference Kopeć, Soszyńska-Maj, Krzemiński and Coram2016). Today, the Bittacidae comprises c.200 species in 19 genera (Penny Reference Penny1997; Collucci & Amorim Reference Chen and Hua2002; Huang & Hua Reference Huang and Hua2005; Cai et al. Reference Cai, Huang and Hua2006; Bicha Reference Bicha2007, Reference Bicha2011; Petrulevičius et al. Reference Petrulevičius, Huang and Ren2007; Hua et al. Reference Hua, Tan and Huang2008; Tan & Hua Reference Tan and Hua2008a, Reference Tan and Huab, Reference Tan and Hua2009a, Reference Tan and Huab; Chen & Hua Reference Chen and Hua2011; Chen et al. Reference Chen, Tan and Hua2013; Garcia-Garcia & Cadena-Castañeda Reference Collucci and Amorim2015), are the second most abundant family of extant scorpionflies after Panorpidae.
The extinct genus Orthobittacus was established by Willmann (Reference Willmann1989) to distinguish and classify a species described previously as Neorthophlebia abshirica Martynova, Reference Martynova1951 from the Lower Jurassic (Lias) of Kirgizia. Martynova (Reference Martynova1951) described the specimen with a characteristic Sc vein unusually long for the Bittacidae. Willmann (Reference Willmann1989) transfered N. abshirica to the new genus Orthobittacus and provided an updated drawing and description of the holotype, with a long Sc and also all characters typical for most Bittacidae, such as four veins in radial and medial sectors. Four years later, Novokshonov (Reference Novokshonov1993a) revised the holotype and published a new drawing of O. abshiricus with seven medial veins (Fig. 1). Additionally, Novokshonov (Reference Novokshonov1996) described a second species, O. polymitus Novokshonov, Reference Novokshonov1996 from the Upper Jurassic of Karatau (Kazakhstan), characterised by a long vein Sc, four veins in the radial sector, and seven medial veins (Fig. 2). In the same year, Ansorge (Reference Ansorge1996) transferred Protobittacus desacuminatus Bode, Reference Bode1953 from Braunschweig (Germany) to the genus Orthobittacus. The fourth congener, O. maculosus Liu, Shih, Bashkuev & Ren, Reference Liu, Shih, Bashkuev and Ren2016, was described recently from the Middle Jurassic Jiulongshan Formation of Daohugou (China). It is characterised by having a radial sector with four veins, and six veins in the medial sector in the forewing as well as in the hindwing (Fig. 3). The wings of both O. polymitus and O. maculosus bear clearly visible and well preserved colour patterns.
Forewing of holotype of Orthobittacus abshirica (Martynova, Reference Martynova1951): (A) drawing, redrawn from Novokshonov (1993, fig. 1); (B) photograph.
Forewing of holotype of O. polymitus Novokshonov, Reference Novokshonov1996: (A) drawing, redrawn from Novokshonov (Reference Novokshonov1996, fig. 1, modified); (B) photograph.
Wings of holotype of O. maculosus Liu, Shih, Bashkuev & Ren, Reference Liu, Shih and Ren2016: (A, C.) forewing; (B, D) hind wing; redrawn from Liu et al. (Reference Liu, Shih, Bashkuev and Ren2016, fig. 5, modified).
A new species herein described from the Jiulongshan Formation of Daohugou (China) is the fifth congener of Orthobittacus, and the second species from the Middle Jurassic of China. Its wings also have a visible colour pattern, but different to those of already described species.
1. Material and methods
The description of a new species is based on a well-preserved female specimen. The holotypes of Orthobittacus polymitus from the collection of the Paleontological Institute, Russian Academy of Sciences in Moscow (PIN) and O. maculosus from the collection of the College of Life Sciences, Capital Normal University (CNU), Beijing, China were used for comparative study.
The specimen of O. suni sp. nov. was studied with the use of a stereomicroscope, under the reflected light. Drawings were based on the photographs and digitally processed in Corel X5. The terminology of wing venation follows Willmann (Reference Willmann1989), with some modifications (Soszyńska-Maj et al. Reference Soszyńska-Maj, Krzemiński, Kopeć and Coram2017 (this volume)) and is presented in Figures 1–3 and Figure 5. The terminology of the female genitalia follows Villagomez et al. (Reference Tillyard2015).
2. Systematic palaeontology
Order Mecoptera Packard, Reference Packard1886 Infraorder Raptipedia Willmann, Reference Willmann and Westphal1987 Family Bittacidae Handlirsch, 1906 Genus Orthobittacus Willmann, Reference Willmann1989
Type species. Orthobittacus abshiricus (Martynova, Reference Martynova1951, pp 1009–10, fig. 1; Novokshonov, Reference Novokshonov1993a, p. 76, fig. 1) – Lower Jurassic (Lias) from the locality of Kyzyl–Kiya (Kirghizia).
Remark. Three Jurassic species from the Laurasian area belong to the genus: O. abshiricus (Lower Jurassic); O. maculosus (Midddle Jurassic); and O. polymitus (Upper Jurassic).
Orthobittacus suni sp. nov. Figs 4–6
Habitus of Orthobittacus suni sp. nov., holotype, CNN-MEC-NN2016101, female.
Drawing of both wings of Orthobittacus suni sp. nov., holotype, CNN-MEC-NN2016101: (A) forewing; (B) hind wing.
Female abdomen of Orthobittacus suni sp. nov., holotype, CNN-MEC-NN2016101. Abbreviations: cr = cerci; sg = subgenital plate; suba = sub-anal plate.
Type material. Holotype No. CNU-MEC-NN2016101 female with well-preserved wings, complete abdomen and parts of legs, without head (part and counterpart), Jiulongshan Formation of Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China – latest Middle Jurassic. Housed in the collection of the College of Life Sciences, Capital Normal University, Beijing, China (CNUB, Curator Dong Ren).
Etymology. The name is dedicated to Mr Sun Qian in acknowledgement of his contribution and hard work in raising the collection of fossil materials from Daohugou, Inner Mongolia, China.
Diagnosis. The new species is distinguished from all other species of this genus by differences in colour markings on the wings, and the proportions of some wing veins. Orthobittacus suni sp. nov. has three wide, transparent cross-bands on both wings, whereas the wings of O. polymitus and O. maculosus have transparent oval spots which do not form bands. The new species is distinguished from O. abshiricus and O. polymitus by six medial veins, and from O. maculosus by the position of the forking of Mb, which in both fore and hind wings of this species is situated opposite mid Rs3+4, whilst in O. suni sp. nov. it is opposite a point a quarter along the length of Rs3+4.
Description. Both wings with well-preserved colour pattern composed of three wide, transparent cross-bands on fore and hind wings.
Forewing. 45 mm long, 14 mm wide, radial sector (Rs) with four veins and medial sector with six veins reaching the outer margin; vein Sc reaching Costa slightly distal to two-thirds wing length and clearly distal to the forking behind forks of Rs into Rs1+2 and into Rs3+4; forking of Rb into R1 and Rs is positioned significantly beyond the fusion of Mb and Cu1; forking of Mb in quarter of length of Rs4+5; R1 long, mildly curved in distal section, terminating just distal of half of Rs1; Rs1+2 almost twice as long as Rs2 and more than twice as long as Rs; Rs3+4 1.25 times as long as Rs; Rs4 almost twice as long as Rs3+4; forking of Rs3+4 into Rs3 and Rs4 positioned slightly distal to forking of M1+2; M1 1.5 times as long as Mb and 2.33 times as long as M1+2; M2 forked into M2a and M2b; M2a 1.5 times as long as M2; M1+2 more than twice as long than M3+4; M3 forked into M3a and M3b; M3 a little longer than M3a; two anal veins A1 and A2 present.
Hindwing. Slightly narrower than forewing; venation and colour pattern similar to forewing, minor differences as follows: R1 is almost straight, forking of Mb opposite one quarter length of Rs4+5, base of vein M4 free, and base of A1 reduced. Abdomen and female genitalia (Fig. 5) well preserved, with subanal plate (1.4 mm×1.25 mm), and short cerci (1.75 mm), broad basally (0.9–1 mm).
3. Discussion
Willmann (Reference Willmann1989) distinguished the genus Orthobittacus based on the long Sc vein. Later, Novokshonov (Reference Novokshonov1996) added the character of the unusually developed medial sector. Although the long Sc vein occurs also in other fossil genera, such as Megabittacus Ren, Reference Ren1997, Sibirobittacus Sukatsheva, Reference Sukatsheva and Rasnitsyn1990, Plesiobittacus Novokshonov, Reference Novokshonov1997a and Composibittacus Liu, Shih, Bashkuev & Ren, Reference Liu, Shih and Ren2016, the medial sector consists usually of four veins, and rarely of five veins, as in the genus Probittacus Martynov, Reference Martynov1927 and Scharabittacus Novokshonov, Reference Novokshonov1993a. Novokshonov (Reference Novokshonov1993b) considered the medial sector consisting of more veins in both wings of the genus Orthobittacus to be a plesiomorphic character. Thus, this established this genus as being at the most basal position of the phylogenetic tree of the Bittacidae, and as a sister group position to all other bittacids (see Fig. 2). The same author, (Novokshonov Reference Novokshonov1997a) created the new subfamily Plesiobittacinae with the Bittacidae, with one genus, Plesiobittacus, and two species: P. martynovi Novokshonov and P. promigenius Novokshonov. In the same paper, Novokshonov (Reference Novokshonov1997a), considered including the genus Orthobittacus in the Plesiobittacinae, but did not do this formally. Bechly & Schweigert (2000) expressed the opinion that both the subfamily Plesiobittacinae and the genus Orthobittacus are taxa of uncertain taxonomic position (sedis mutabilis).
In summary, the genus Orthobittacus, with its plesiomorphic features of the medial sector, is of extraordinary importance for the phylogeny of Bittacidae as the stem taxon.
4. Acknowledgements
We would like to thank Alexandr Rasnitsyn for the opportunity to work, and for his hospitality, at the Paleontological Institute, Russian Academy of Sciences in Moscow, Russia. We are most grateful to Chunkung Shih and Alexei Bashkuev for their very helpful comments and to Ewa Krzemińska for the language correction of the previous version of the manuscript. The research was supported by the Polish National Science Center (grant no.2013/09/B/NZ8/03270). YC and DR were supported by grants from the National Natural Science Foundation of China (No. 31230065), Program for Changjiang Scholars and Innovative Research Team in University (IRT13081).
