Two new fossil species of Omaliinae from Baltic amber (Coleoptera: Staphylinidae) and their significance for understanding the Eocene-Oligocene climate Zanetti, Adriano; Perreau, Michel; Solodovnikov, Alexey Published in: arthropod systematics & phylogeny Publication date: 2016 Document version Publisher's PDF, also known as Version of record Document license: Other Citation for published version (APA): Zanetti, A., Perreau, M., & Solodovnikov, A. (2016). Two new fossil species of Omaliinae from Baltic amber (Coleoptera: Staphylinidae) and their significance for understanding the Eocene-Oligocene climate. arthropod systematics & phylogeny, 74(1), 53-64. Download date: 08. Apr. 2020 74 (1): 53 – 64 14.6.2016 © Senckenberg Gesellschaft für Naturforschung, 2016. Two new fossil species of Omaliinae from Baltic amber (Coleoptera: Staphylinidae) and their significance for understanding the Eocene-Oligocene climate Adriano Zanetti 1, Michel Perreau *, 2 & Alexey Solodovnikov 3 1 Museo Civico di Storia Naturale, Lungadige Porta Vittoria 9, I-37129 Verona, Italy; Adriano Zanetti [[email protected]] — 2 Université Paris Diderot, Sorbonne Paris Cité, IUT Paris Diderot, case 7139, 5, rue Thomas Mann, F-75205 Paris cedex 13 France; Michel Perreau * [michel. [email protected]] — 3 Department of Entomology, Zoological Museum, Natural History Museum of Denmark, Universitetsparken 15, Copenhagen 2100, Denmark; Alexey Solodovnikov [[email protected]] — * Correspond ing author Accepted 23.ii.2016. Published online at www.senckenberg.de/arthropod-systematics on 03.vi.2016. Editor in charge: Christian Schmidt. Abstract Two fossil species, Paraphloeostiba electrica sp.n. and Phyllodrepa antiqua sp.n. (Staphylinidae, Omaliinae), are described from Baltic amber. Their external and relevant internal structures are illustrated using propagation phase contrast synchrotron microtomography. The palaeobiogeogaphy of the two genera, the thermophilous Paraphloeostiba, the temperate Phyllodrepa, as well as palaeoenvironment of the amber forest are discussed in light of the new findings. Key words Omaliini, Eusphalerini, synchrotron microtomography, temperate, thermophilous. 1. Introduction With more than 60,000 described living species (SOLO- like pattern, patches of wing folding, microtrichia on DOVNIKOV et al. 2013) Staphylinidae (rove beetles) is the some abdominal tergites, as well as some features of most speciose family of Coleoptera, presently divided genitalia (THAYER 1985a; PERIS et al. 2014). To date, 17 into 32 subfamilies. Among them the subfamily Omali- Mesozoic fossil species, mostly compression fossils that inae is moderately large (about 1,500 described species) are thought to belong to Omaliinae have been reported: and one of the oldest rove beetle groups, known since the 13 from the Jurassic and 4 from the Cretaceous (TIKHOMI- Mesozoic (TIKHOMIROVA 1968). The presence of a pair of ROVA 1968; RYVKIN 1985, 1990; HERMAN 2001; CHATZI- ocelli on the vertex of the head is the most characteristic MANOLIS & ENGEL 2011; CHATZIMANOLIS et al. 2012; CAI omaliine feature since the ocelli occur only in a few other & HUANG 2013; PERIS et al. 2014). But their systematic staphyliniform beetle families (THAYER 1985a; LESCHEN positions, especially tribal or generic assignment within & BEUTEL 2004). Other characters which are classically the subfamily, are still uncertain. Among them only Duo­ distinctive for the Omaliinae within Staphylinidae are calcar geminum Peris & Thayer, 2014 from Cretaceous tarsal formula 5-5-5, procoxal cavities opened behind, amber, studied by the same techniques used in this paper, well-developed prosternal and postprocoxal processes, is to be considered as a reliably identified extinct Meso- abdominal intersegmental membranes with brick-wall- zoic taxon. Many more amber preserved fossils of rove ISSN 1863-7221 (print) | eISSN 1864-8312 (online) 53 Zanetti et al.: New fossils of Omaliinae from Baltic amber beetles are known from the Cenozoic. In particular, 82 for examination of the ventral side of the body fully con- species of Staphylinidae were described from Baltic am- cealed by non-transparent milky substance common in ber (40 – 50 mya), belonging to Aleocharinae (8), Omali- Baltic amber fossils. The microtomographic scans of the inae (1), Oxyporinae (1), Paederinae (5), Pselaphinae samples were performed on beamline ID19 of the Eu- (33), Scydmaeninae (19), Staphylininae (2), Steninae ropean Synchrotron Radiation Facility (ESRF, Grenoble, (9), and Tachyporinae (4) (CHATZIMANOLIS & ENGEL 2011; France). Scans were performed with a monochromatic PARKER & GRIMALDI 2014). The only putative omaliine X-ray beam at the energy of 15 Kev using a multilayer in this list, Pseudolesteua insinuans Schaufuss, 1890, monochromator. The CCD detector was a FreLoN HD2k has never been revised since its original description by (fast read-out low noise) with 2048×2048 pixels. Two SCHAUFUSS (1890). The diagnosis of Pseudolesteua in resolutions were used: 0.678 μm (distance sample-de- the original description is insufficient for its unambigu- tector 30 mm, range angle 180°) and 1.75 μm (distance ous identification, but contains enough information to sample-detector 70 mm, range angle 360°). 1999 pro- rule out any close affinity of that fossil with the two jections were acquired for each scan and performed by new species described here. Based on SCHAUFUSS (1890), continuous rotation to blur out details located outside the who only pointed to some habitus resemblance of Pseu­ field of interest (far from rotation center and generally dolesteua with two omaliine genera (he wrote: “Dieser undesired) in order to decrease their contribution to the Staphyline [Pseudolesteua] hat etwa die Form einer Les­ noise of the final reconstructed slices (LAK et al. 2008). teua, ist aber schmäler und nähert sich dadurch mehr im Tomographic reconstructions were made using inhouse Habitus einem Boreaphilus”), we cannot be even sure software of ESRF. Segmentations of selected structures that Pseudolesteua in fact represents an omaliine. An- were made with the software VGSTUDIOMAX 2.1 of other omaliine known from the Baltic amber is the genus Volume Graphics (http://www.volumegraphics.com/en/ Eusphalerum reported by HIEKE & PIETRZENIUK (1984) products/vgstudiomax.html). Microtomographic data based on material identified by E. Reitter. It was reported linked to these specimens (original slices and processed as an undescribed species of Anthobium, the genus name data) and used for the present analysis are publicly avail- wrongly used for the current Eusphalerum until the mid- able on the ESRF online paleontological database http:// dle of the last century (TOTTENHAM 1949). As a result, two paleo.esrf.eu. species that we are describing here are the first reliably Habitus pictures in Figs. 33 – 35 were photographed recorded fossil Omaliinae from Baltic amber. Because on a Visionary Digital system, using Adobe Lightroom the groups they belong two are systematically complex (Adobe Systems Inc. 2006 – 09). and require examination of characters difficult to observe with light microscopy, we used propagation phase con- trast synchrotron microtomography for detailed study of the specimens. 3. Systematics 2. Material and methods Order Coleoptera Linnaeus, 1758 Family Staphylinidae Latreille, 1802 Four pieces of Baltic amber, each with one inclusion of Subfamily Omaliinae MacLeay, 1825 Staphylinidae Omaliinae belonging to the Zoological Tribe Omaliini MacLeay, 1825 Museum, Natural History Museum of Denmark, Copen- hagen (ZMUC) were tentatively identified by V. Puthz as Eusphalerum sp. This paper deals with two of these Genus Paraphloeostiba Steel, 1960 specimens, referenced as ZMUC-900029 and ZMUC- 900027. The other two, referenced as ZMUC-900028 and Paraphloeostiba electrica sp.n. ZMUC-900026 (with an additional old handwritten label Figs. 1 – 7, 9 – 20, 32 – 34 “Baltic amber” and a recent printed label, with “Staphyli- nidae Liban, 1941 – 43 Kobmand Tidemand M.M.”), are Material. Holotype ♂: as inclusion in a piece of amber 9 mm × 5 still under study [according to Lars Vilhelmsen, ZMUC mm × 2.5 mm in size, with one aphid as syninclusion, in paper amber collection curator, ‘Liban’ on the label has no rela- envelope with the following 3 handwritten labels: “Staphylini- dae Thysanoptera (?) [crossed out in pencil] C.V. Henningsen 1-5 tion to Lebanon or Lebanese amber]. 1967”; “Eusphalerum spec. det. Puthz 1974”; “Eusphalerum sp. External and internal structures are illustrated using det. Solodovnikov 2007”, inserted in transparent plastic envelope propagation phase contrast synchrotron microtomogra- with the following printed label: “SNM Amber Collection/ZMUC- phy (PPC-SRμCT), which allows a complete virtual dis- 900029/ Class: Insecta/ Order: Coleoptera/ Family: Staphylini- dae/ Eusphalerum sp./ Baltic Amber/ Leg. C.V. Hennigsen date: section of specimens in a non-destructive way (TAFFOR- 1.5.1967/ Dep. ZMUC”, the following handwritten label: “MP018” EAU et al. 2006; PERREAU & TAFFOREAU 2011). This tech- (reference of ESRF scan), and the following printed label (red): nique was particularly useful for the study of genitalia “Paraphloeostiba electrica n. sp. Zanetti, Perreau and Solodovnik- in both specimens, and, in case of Phyllodrepa antiqua, ov, 2014 HOLOTYPE”. The holotype is deposited in the ZMUC. 54 ARTHROPOD SYSTEMATICS & PHYLOGENY — 74 (1) 2016 Figs. 1 – 6. Paraphloeostiba electrica sp.n. 1: Habitus, dorsal view. 2: Habitus, lateral view. 3: Habitus ventral