Accepted Manuscript Burmusculidae, a new and basal family of pompiloid wasps from the Cretaceous of Eurasia (Hymenoptera: Pompiloidea) Qi Zhang, Alexandr P. Rasnitsyn, Haichun Zhang PII: S0195-6671(18)30071-5 DOI: 10.1016/j.cretres.2018.07.004 Reference: YCRES 3917 To appear in: Cretaceous Research Received Date: 20 February 2018 Revised Date: 29 May 2018 Accepted Date: 3 July 2018 Please cite this article as: Zhang, Q., Rasnitsyn, A.P., Zhang, H., Burmusculidae, a new and basal family of pompiloid wasps from the Cretaceous of Eurasia (Hymenoptera: Pompiloidea), Cretaceous Research (2018), doi: 10.1016/j.cretres.2018.07.004. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT 1 Burmusculidae, a new and basal family of pompiloid wasps from the Cretaceous of Eurasia 2 (Hymenoptera: Pompiloidea) 3 4 Qi Zhang a,b,c , Alexandr P. Rasnitsyn d,e *, Haichun Zhang b 5 6 a School of Geography and Tourism, Qufu Normal University, Rizhao 276826, China 7 b State Key Laboratory of Palaeobiology and Stratigraphy, Center for Excellence in Life and 8 Paleoenvironment, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 9 Nanjing 210008, China 10 c University of Chinese Academy of Sciences, Beijing 100049, China 11 d A.A. Borissiak Palaeontological Institute, Russian Academy of Sciences, Moscow 117647, Russia 12 e Natural History Museum, Cromwell Road, London SW7 5BD, UK 13 *Corresponding author. Email:MANUSCRIPT [email protected] 14 15 Abstract 16 A group of aculeate wasps from mid-Cretaceous Burmese amber is described as Burmusculus 17 Zhang and Rasnitsyn, gen. nov. in Burmusculidae Zhang and Rasnitsyn, fam. nov. The type genus 18 Burmusculus contains three species: Burmusculus nuwae Zhang and Rasnitsyn sp. nov., 19 Burmusculus fuxii Zhang and Rasnitsyn, sp. nov., and Burmusculus shennongii Zhang and 20 Rasnitsyn, sp . nov. It does not fit any described families and therefore is referable to a new family. 21 The family displaysACCEPTED some features in common with the living family Pompilidae but can be easily 22 distinguished from Pompilidae in having the mesopleuron lacking an oblique suture. Hence it is 23 assigned to the superfamily Pompiloidea (monotypical as yet in our understanding) as the second 24 member. 25 ACCEPTED MANUSCRIPT 26 Keywords: Hymenoptera, Pompiloidea, Burmusculidae, mid-Cretaceous, Burmese amber 27 28 1. Introduction 29 The system and phylogeny of the aculeate wasps are currently to be attested as being in a 30 chaotic state. Before the time of molecular phylogenetics, students were in broad disagreement from 31 each other in various aspects, and yet there was a general consensus in respect to some important 32 points including the monophyly of superfamilies Chrysidoidea and Apoidea, and the position of 33 Chrysidoidea as a sister of the aculeate clade, and of Apoidea as a sister of non-chrysidoid Aculeata, 34 either alone or accompanied with Pompilidae (sometimes also with Rhopalosomatidae) (Brothers, 35 1975; Rasnitsyn, 1980, 1988, 2002; Brothers and Carpenter, 1993; Ronquist et al. 1999). However, 36 molecular data has turned the aculeate clade into a complete mess. Even the newest results 37 published after 2010 (Heraty et al., 2011; Peters et al., 2011, 2017; Sharkey et al., 2012; Johnson et 38 al., 2013; Klopfstein et al., 2013; Smith et al., 2015,MANUSCRIPT Branstetter et al., 2017) never display 39 Chrysidoidea as monophyletic, and show Apoidea usually monophyletic but rooted deep within the 40 cladogram and each time with different sister groups. The above results often show Pompilidae as 41 monophyletic with Mutillidae, either together with Sapygidae or not (Peters et al., 2011, 2017; 42 Sharkey et al., 2012; Johnson et al., 2013; Klopfstein et al., 2013 (except for a tree on fig. 2 with 43 Pompilidae shown as monophyletic with Tiphiidae); Smith et al., 2015; Braunstetter et al., 2017). 44 However, other results show Pompilidae as monophyletic with other taxa, namely 45 Rhopalosomatidae (Vilhelmsen and Turrisi, 2011), Scoliidae (Heraty et al., 2011, figs. 1, 3), or with 46 Chrysididae nextACCEPTED to a part of Apoidea (Heraty et al., 2011, fig. 2). The reasons for this failure are 47 debatable and lie outside the scope of the present publication (the opinion of one of the authors is 48 presented by Rasnitsyn, 1996, 2006, 2010). These circumstances force us to rely on the comparative 49 morphological and paleontological data when dealing with the accumulated and not assimilated yet 50 abundant Cretaceous fossils of Aculeata. ACCEPTED MANUSCRIPT 51 The primary aim of the present paper is to describe a group of mid-Cretaceous aculeate wasps 52 from the Burmese amber which does not fit any described family even though it displays some 53 features in common with the living family Pompilidae that is in turn of questionable taxonomic 54 position and has an unusually short fossil record (Rodriguez et al., 2016, 2017). 55 To define the pompiloid clade of Aculeata, we rely on the features identified as indicative by 56 Brothers (1975) and Rasnitsyn (1980, 1988). These include, the first, the sexually dimorphic antenna 57 (12-segmented in female and 13-segmented in male), the only synapomorphy of the non-chrysidoid 58 aculeates (Aculeata s.str. sensu Rasnitsyn, 1980) available in fossils, usually combined with the hind 59 wing with the jugal lobe retained (a plesiomorphy of Aculeata s.str., apomorphically lost in 60 Chrysidoidea). Within Aculeata s.str., Pompiloidea (= Pompilidae s.l. that is, including Ceropalidae) 61 are unique in retaining in their ground-plan (and in vast majority) a plesiomorphic metapostnotum 62 which is fully external, ribbon-like and not impressed (apomorphically impressed and rather narrow 63 in some disparate genera, e.g. Machaerothrix Haupt,MANUSCRIPT Nipponopogon Ishikawa, Homonotus 64 Dahlbom, but in known cases not as invaginated and as hidden as in any Vespoidea s.l.). In contrast, 65 Apoidea have a far widened metapostnotum posteriorly forming a propodeal enclosure, whilst in the 66 remaining non-chrysidoid Aculeata (Vespoidea other than Pompilidae) it is narrow, groove-like and 67 impressed (in Sierolomorphidae) or completely invaginated between the metanotum and the 68 propodeum and scarcely or, usually, not at all visible externally. This unique pompilid 69 autoplesiomorphy is combined with the non-unique synapomorphy that the mid coxa is narrowly 70 attached to the mesosoma. Until the molecular data are as contradictory as it is referred to above, we 71 feel it possibleACCEPTED to limit ourselves with morphological information. This makes it possible to consider 72 Pompiloidea tentatively a monophyletic clade in unresolved sister relation to both Apoidea and the 73 remaining Vespoidea s.l. (excluding Pompilidae). Pompilidae is known to have more putative 74 non-unique synapomorphies such as mesopleuron with oblique suture traversing it towards the fore 75 margin of mesoventropleuron, and using spiders as larval food. The latter feature is unfortunately ACCEPTED MANUSCRIPT 76 inapplicable to fossils, and the former one is not found in the fossils under description below and so 77 is considered here as defining Pompilidae in contrast to our fossils. The line found in one of these 78 (Figs 3A, 4B) runs much more ventral and so probably represent a different structure than the 79 oblique suture of Pompilidae. 80 The principal material of the present work comes from the mid-Cretaceous Burmese amber, 81 now the richest source of knowledge of Cretaceous insects (Rasnitsyn et al., 2016). The Burmese 82 amber assemblage of Hymenoptera is found to be particularly rich in non-chrysidoid and non-ant 83 aculeate wasps and opens a unique way to consider the Cretaceous diversity of these insects. The 84 present publication is one of a series planned to pursue this aim. 85 2. Material and methods 86 All the specimens described in this paper were collected from the amber mines sited in the 87 Hukawng Valley of Kachin State, Myanmar (locality in Kania et al., 2015: fig. 1). The rock 88 containing the Burmese amber was radiometricallyMANUSCRIPT dated at 98.79 ± 0.62 Ma (Shi et al., 2012). 89 However, we prefer to refer to the amber age informally as mid-Cretaceous, because the amber 90 could be re-deposited (Smith and Ross, 2018) and hence older than the enclosing rocks. 91 All the materials are deposited in the Nanjing Institute of Geology and Palaeontology, Chinese 92 Academy of Sciences (NIGPAS). The ambers were studied under a Nikon SMZ-10 R stereoscopic 93 microscope and a Nikon Optiphot compound microscope with magnifications up to 800× at the 94 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and 95 Palaeontology, Chinese Academy of Sciences, and using a Leica M165C stereomicroscope with a 96 Leica DFC 420ACCEPTED camera at the A.A. Borissiak Paleontological Institute, Russian Academy of 97 Sciences, in Moscow. Helicon Focus Pro ×64 was used to stack photos for better depth of field. Line 98 drawings were done using image-editing software (CorelDraw X7 and Adobe Photoshop CS6) on 99 the basis of digital photographs. All taxonomic acts established in the present work have been ACCEPTED MANUSCRIPT 100 registered in ZooBank (see below), together with the electronic publication LSID: 101 urn:lsid:zoobank.org:pub:C638CADF-40A4-406C-8176-88D1950C3CC0 102 3. Systematic paleontology 103 Order Hymenoptera 104 Infraorder Vespomorpha Laicharting, 1781 105 Superfamily Pompiloidea Latreille, 1804 106 107 Emended diagnosis (addressed primarily to fossils).