A new species of Hemerobiidae, Wesmaelius makarkini Yang, Pang & Ren, sp. n. is described from the Lower Miocene, Garang Formation of Zeku County, Qinghai Province (northeastern Tibetan Plateau), China. The species is assigned to the widely distributed extant genus Wesmaelius Krüger (Hemerobiinae). The species represents the first named fossil of this family from China, which sheds light on the historical distribution of Wesmaelius and early divergences within Hemerobiinae.

Cenozoic, China, Wesmaelius

Hemerobiidae, commonly known as brown lacewings, are the third largest family of Neuroptera, with about 520 species assigned to 27 genera (Oswald 2017). Hemerobiids are the most widely distributed lacewings, from subpolar tundra to tropical regions (Oswald 1993, 2017; Monserrat 2000; Makarkin et al. 2016). The extant brown lacewings have been comprehensively studied by Oswald (1993) including a taxonomic revision, a genus-level phylogeny based on morphology, and the establishment of a subfamilial classification. Recently, Garzón-Orduña et al. (2016) provided a total evidence phylogeny of the family based on combined data of morphological characters and DNA. As a result, seven known subfamilies were recovered to be monophyletic, with the addition of a new subfamily and the revision of Notiobiellinae (Garzón-Orduña et al. 2016).

Compared with its putative sister group Chrysopidae, Hemerobiidae have a relatively sparse and recent fossil record (Haring and Aspöck 2004; Winterton et al. 2010; Wang et al. 2016), although in a recent study, Hemerobiidae are not sister to Chrysopidae, but to the clade including Mantispoidea, Chrysopoidea, and Myrmeleontoidea (Winterton et al. 2017). Only four species have been described from the Mesozoic, with the earliest from the Late Jurassic. All the other 19 species have been described from the Cenozoic, from the Eocene to the Miocene (Makarkin et al. 2003, 2016; Engel and Grimaldi 2007) (Table 1). The Mesozoic hemerobiids comprise four monotypic extinct genera, one from the Late Jurassic of Kazakhstan, two from the Early Cretaceous of Mongolia and England, and one from the Late Cretaceous of Canada (Panfilov 1980; Ponomarenko 1992; Jepson et al. 2012; Klimaszewski and Kevan 1986; Makarkin et al. 2003, 2016). In the Cenozoic, 10 genera have been described from Russia, Baltic amber, Denmark, England, Canada, USA, and Dominican amber (Pictet-Baraban and Hagen 1856; Scudder 1878, 1890; Henriksen 1922; Krüger 1923; Jarzembowski 1980; Makarkin 1991; Oswald 2000; Makarkin et al. 2003; Makarkin and Wedmann 2009; Jepson et al. 2010), as well as China in this paper.

Fossil hemerobiids have never been described from China. Mesohemerobius jeholensis Ping, from the Lower Cretaceous, Yixian Formation of China, was previously placed in Hemerobiidae, but was later excluded from the family by Makarkin et al. (2003) and referred as Neuropteraincertae sedis. Wang et al. (2014) mentioned hemerobiids in Fushun amber, but with no descriptions or figures. Herein, we describe a new species of Wesmaelius Krüger (Hemerobiidae: Hemerobiinae) from the Lower Miocene of the northeastern Tibetan Plateau in China. The species is the first named fossil of the family Hemerobiidae in China.

The specimen was collected from the Guide Group at Caergen Village, Duohemao Town, Zeku County, eastern Qinghai Province, China (34°56'N, 101°48'E, 3700 m a.s.l.) (fig. 1 in Li et al. 2017). The stratum is a papery oil shale deposit and constitutes a lacustrine–fluvial sedimentary succession (fig. 1 in Li et al. 2016), belonging to the Garang Formation (<16–19 Ma), the Lower Miocene. The deposit yielded abundant, exquisitely preserved fossil plants (Guo 1980; Fang et al. 2005, 2007), bird feathers (Yang 1975), and insects including representatives of Hemiptera (Li et al. 2017), Diptera, Hymenoptera, Neuroptera, Mecoptera, Odonata and Coleoptera (pers. obs.). The specimen is housed in the collection of the Key Laboratory of Insect Evolution & Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China (CNUB; Dong Ren, Curator).

The specimen was examined using a Zeiss Discovery V20 stereomicroscope and photographed with an AxioCam HRc digital camera attached to the Zeiss Discovery V20 stereomicroscope (both instruments Carl Zeiss Light Microscopy, Göttingen, Germany). Line drawings were prepared with the CorelDraw 12 graphics software and with the aid of Adobe Photoshop CS6. The vein terminology in general follows Yang et al. (2012, 2014). Terminology of wing spaces and details of venation (e.g., veinlets, traces, ‘oblique radial branches’ (“ORB”) concept) follows Oswald (1993).

Venation abbreviations used in the text and figures:

AA1–AA3 first to third anterior anal vein;

CuA anterior cubitus;

CuP posterior cubitus;

hv humeral veinlet;

fl flexion fold line;

MA anterior branche of media;

MP posterior branche of media;

ORB1, ORB2, ORB3 first to third oblique radial branches;

RA anterior radius;

RP posterior sector;

ScA subcosta anterior;

ScP subcosta posterior.

Named fossil Hemerobiidae have been described from the Late Jurassic to the Miocene, including four extinct genera from the Mesozoic and 11 genera from the Cenozoic (Table 1). Among the Cenozoic genera, six of them are extant genera, belonging to five subfamilies (Drepanepteryginae, Sympherobiinae, Megalominae, Hemerobiinae, Notiobiellinae), which are distributed in the three main clades of Hemerobiidae according to Garzón-Orduña et al. (2016). The earliest fossil record of each of the five subfamilies are from the Eocene of Europe and North America, indicating these extant subfamilies have been well differentiated and widely distributed across the Northern hemisphere by the Eocene.

Wesmaelius is an extant genus with approximately 62 extant species and two fossil species from the Eocene of Canada (Makarkin et al. 2003) and the Miocene of China (as afore-described). The extant species are widely distributed in the Palearctic, Nearctic, Afrotropic, and Indomalaya, with the majority of species widely distributed across the northern hemisphere; only four species are found in the southern hemisphere (Makarkin et al. 2003; Oswald 2017). Nearly all of them are restricted from the tropical to the temperate zone, and most of them restricted to higher elevation montane region. The genus apparently is distributed from the north to the south, but the center of origin of Wesmaelius is questionable, mainly because the generic assignment of the oldest species (i.e., W. mathewesi) from the Eocene of Canada is uncertain (Makarkin et al. 2003). Nevertheless, W. mathewesi shows high affinity to the genera of Wesmaelius and Hemerobius, both of which belong to the subfamily Hemerobiinae. Therefore, it represents one of the earliest fossil records of the subfamily to date. Hemerobius also has fossil records extending back to the Miocene (Makarkin 1991). The geological history of the Hemerobiinae is still uncertain, due to the undetermined subfamilial assignment of the extinct genera, which requires further study.

We thank Dr. Chungkun Shih (College of Life Sciences, Capital Normal University and National Museum of Natural History, Smithsonian Institution) for his helpful comments, fruitful suggestion and improvement of our manuscript. We are grateful to Dr. Shaun L. Winterton (California State Arthropod Collection, California Department of Food and Agriculture, Sacramento, USA) for his kind help and permitting us to check the extant hemerobiids specimens. We sincerely thank Drs Yunzhi Yao and Junjie Gu, Zhipeng Zhao, Lei Li, Yizi Cao, Yingnan Li, Siyuan Wu, and He Tian for collecting specimens. We appreciate the valuable comments and useful suggestions on our manuscript from reviewers and the editor. This research was funded by grants from key project of Science-technology basic condition platform from The Ministry of Science and Technology of the People’s Republic of China (grant no. 2005DKA21402), the specimen platform of China, teaching specimens sub-platform, Web, http://mnh.scu.edu.cn/, National Natural Science Foundation of China (grant nos. 41602014, 31501881, 41402009, 31730087), China Postdoctoral Science Foundation (grant no. 2016M592570), Natural Science Foundation of Hebei Province (grant no. C2015403012), Basal Research Fund of SYSU (grant nos. 32110-41030349) and Program for Changjiang Scholars and Innovative Research Team in University (grant no. IRT-17R75).