Mecoptera is a small order of insects, comprising about 600 extant species assigned to nine families (Cai et al. 2008, Krzemiński and Soszyńska-Maj 2012). The Panorpidae is the largest family in the order, with about 400 extant species in six genera: Panorpa Linnaeus, 1758, Leptopanorpa MacLachlan, 1875, Neopanorpa Weele, 1909, Sinopanorpa Cai, Huang & Hua, 2008, Furcatopanorpa Ma & Hua, 2011 and Dicerapanorpa Zhong & Hua, 2013 (Byers 1967, Cai et al. 2008, Cai and Hua 2009, Ma and Hua 2011, Zhong and Hua 2013).

Fossil records of the Panorpidae are fairly rare. Up to date, only three genera have been described in this family and two of them are fossil-only genera: Solusipanorpa Lin, 1980 with one species from the Early Cretaceous of China (Lin 1980); Baltipanorpa Krzemiński, 2012 with one species from the Eocene Baltic amber (Krzemiński and Soszyńska-Maj 2012); and Panorpa Linnaeus, 1758 with seven species from Baltic amber, Eocene of U.S.A. and Oligocene of Germany (Carpenter 1931, Statz 1936, Carpenter 1954). However, the holotype (and the only known specimen) of Solusipanorpa gibbidorsa is too incompletely preserved and cannot be attributed to any particular family. In addition, Archibald et al. (2013: fig. 23) reported several undescribed specimens of Panorpidae in the Early Eocene Okanagan Highlands, Canada and U.S.A. Therefore, with Solusipanorpa gibbidorsa ignored, the fossil records of Panorpidae are known so far since the Early Eocene.

Recently we collected four well-preserved fossils, which we attribute to Panorpidae, from the Jiulongshan Formation at Daohugou, Ningcheng County, Inner Mongolia, China. The Jiulongshan Formation is dated as the late Middle Jurassic, ca. 165 Ma (Ren et al. 1995, 2002, Shen et al. 2003, Chen et al. 2004, Liu et al. 2004, Ji et al. 2006, Gao and Ren 2006, Huang et al. 2006, Wang et al. 2013). Based on a combination of forewing characters: both R₁ and Rs₁ with two branches, 1A reaching posterior margin of wing distad of the forking of Rs from R_1, and no crossveins or only one crossvein between veins 1A and 2A, we erect a new genus Jurassipanorpa with two new species.

This study is based on four fossil specimens collected from the late Middle Jurassic Jiulongshan Formation at Daohugou Village of Ningcheng County in Inner Mongolia, China. All type specimens are housed in the fossil insect collection of the Key Laboratory of Insect Evolution & Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China (CNUB; Dong Ren, Curator).

The specimens were examined and photographed using a Leica MZ12.5 dissecting microscope with a Leica DFC 500 digital camera and illustrated with the aid of a drawing tube attachment. The line drawings were drawn by Adobe Photoshop CS5. We use the venational nomenclature of Willmann (1989).

In the vast insect fossil collection at the Capital Normal University (> 250, 000 fossil insect specimens), we have collected only four panorpid fossils so far from the Daohugou locality. Informal survey of the Mecoptera collection indicates that specimens of Nannochoristidae are abundant, followed by many specimens of Orthophlebiidae, Bittacidae, and Cimbrophlebiidae, then, low numbers of Choristopsychidae, Mesopsychidae, Aneuretopsychidae, Pseudopolycentropodidae, and Eomeropidae, while very rare for Panorpidae. It is interesting to note that the rarity of Panorpidae during the Middle Jurassic of northeastern China is in contrast to their dominance in the Recent world fauna of Mecoptera (about 66% of all extant species).

Described fossil records of the Panorpidae in Mesozoic are extremely rare. Up to now, only one species, Solusipanorpa gibbidorsa Lin, 1980, has been described. However, we consider the holotype of Solusipanorpa gibbidorsa as not sufficiently preserved to be attributed to Panorpidae nor to any other family, and regard Solusipanorpa gibbidorsa as Mecoptera incertae sedis. Eight species in two genera: Panorpa Linnaeus, 1758, and Baltipanorpa Krzemiński, 2012, have been reported from the Eocene and Oligocene, however Carpenter stated that “Panorpa rigida Scudder, from the Florissant shales, is too incompletely preserved to permit even family classification.” and “Panorpa arctiiformis Cockerell, also from the Florissant shales, is undoubtedly a member of the family Panorpidae, but I have not seen the type specimen and there is nothing in the description to indicate its affinities.” (Carpenter 1931, Carpenter 1954, Willmann 1989, Krzemiński and Soszyńska-Maj 2012, Archibald et al. 2013). Jurassipanorpa impunctata gen. et sp. n. and Jurassipanorpa sticta sp. n. described in this study are the earliest fossil panorpids in the world hitherto. The holotypes of these two new species of Jurassipanorpa gen. n. are well-preserved, including both wings and most of the body. New information from these two new species enhances our understanding of the morphological characters of Panorpidae and diversity of Mecoptera during the late Middle Jurassic.

Based on studies of these two new species and documented species of other representative panorpids, we compare and summarize six key forewing characters in Table 1. A combination of the following characters enables us to distinguish the new genus from all other described genera of Panorpidae: (1) R₁ with two branches in forewing – same as Baltipanorpa, Furcatopanorpa and a rare few species of Panorpa, but different from all other genera with only one branch; (2) Rs₁ with two branches of Rs_1a and Rs_1b – different from Sinopanorpa with 3 branches; (3) 1A reaching posterior margin distad of the forking of Rs from R₁ in forewing – same as Panorpa, Sinopanorpa, Furcatopanorpa, Dicerapanorpa, and Baltipanorpa, in contrast to significantly shortened 1A in Neopanorpa and Leptopanorpa; (4) no crossveins or only one crossvein between 1A and 2A on forewing – different from almost all other genera of Panorpidae, Neopanorpa and Leptopanorpa (one crossvein), Panorpa (one or two crossveins), Sinopanorpa, and Dicerapanorpa (two crossveins), Baltipanorpa and Furcatopanorpa (three crossveins); (Byers 1967, Cai et al. 2008, Ma and Hua 2011, Krzemiński and Soszyńska-Maj 2012, Zhong and Hua 2013).

We found that the wing venation of this family is comparatively stable, that is, Sc not forking, Rs₂, Rs₃, Rs₄ without forking, and M with 4 branches. However, Rs₁ is rather variable, typically, Rs₁ has two branches, but, some with three branches such as Sinopanorpa, while three Mexican extant species Panorpa dividilacinia, P. mixteca, P. umbricola have only a single Rs₁ (Carpenter 1992, Bicha 2006, Cai et al. 2008).

Most panorpids have M₄ bending basally in forewings, that is, M₃ is a straight branch while M₄ is derived from M₃ with a basal bending. However, this character is not obvious for some extant panorpids, such as Panorpa wangwushana Huang, Hua and Shen, 2004 (Huang et al. 2004). On the other hand, most panorpodids have M₃ bending basally in forewings, that is, M₄ is a straight branch while M₃ is derived from M₄ with a basal bending. However, Panorpodes colei Byers, 2005 is an exception to this typical panorpodid character (Byers 2005). Jurassipanorpa impunctata gen. et sp. n. has M₄ bending basally in forewing (Figs 2A, C), but Jurassipanorpa sticta sp. n. does not have obvious M₄ bending basally, nor M₃ bending basally (Figs 4A, C). Hence, we propose that M₄ or M₃ basal bending is variable in both Panorpidae and Panorpodidae.

All four specimens of Jurassipanorpa impunctata gen. et sp. n. (Figs 1B, D, 2D, F) and Jurassipanorpa sticta sp. n. (Figs 3C, E, 4E, F) have remarkable long and robust setae on anal veins of the forewings that are not known for any other described fossil or extant panorpid species. Unlike these of Jurassipanorpa gen. n., setae on veins of extant species of Panorpidae as well as of Mesozoic Orthophlebiidae are usually more dense, shorter and decumbent unidirectionally and look similar to microtrichia on the wing membrane (Tillyard 1933, Webb and Penny 1979, Whalley 1985, Whalley 1986). These setae of the new genus, with lengths ranging from 0.09 to 0.38 mm, are similar in appearance to the piliform scales, ranging from 0.12 to 0.21 mm in lengths, present on the hind wing veins of Akainalepidopteron elachipteron Zhang, Shih, Labandeira & Ren, 2013 of Lepidoptera (Zhang et al. 2013), or to robust bristles (“dinotrichia”) on the basal anterior margin of forewings on the Recent Notiothauma reedi and fossil Tsuchingothauma shihi and Jurathauma simplex (Eomeropidae) (Crampton 1930, Ren and Shih 2005, Zhang et al. 2011). The wing scales have been used as a diagnostic character for Lepidoptera, while also found in some forewings of Trichoptera (Kristensen 1984, Grimaldi 1999, Zhang et al. 2013). However, it is unlikely that these setae are homologous to piliform scales because scales have not been reported for Panorpidae. Since these setae are located only on anal veins of the forewings while all pointing anteriorly, we hypothesized that they might have been used for wing coupling. But, we could not find any associated structures preserved on the anterior part of the hind wings on these specimens. Hence, the function of these setae remains enigmatic.