The oldest osoriine rove beetle from Cretaceous Burmese amber (Coleoptera: Staphylinidae)

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    the antiquity of the subfamily, but also bears signicant biogeographic implications. 2014 Elsevier Ltd. All rights reserved.

    speciehe mobennike beetxcept

    Sinolispinodes torosus Zhang, from the Miocene in Shanwang ofShandong Province, China. Sinolispinodeswas then transferred fromOxytelinae to Osoriinae as supported by the absence of paratergiteson abdominal segments (Herman, 2001; Yue et al., 2010). Irmler

    y history of Osor-

    lder osoriine rovei et al., 2012) as ar. Based on UePbca. 99 Ma) for thelished (Shi et al.,of the previouslydest record for the

    subfamily Osoriinae.

    2. Material and methods

    The material described here derives from amber deposits inthe Hukawng Valley of northern Myanmar. The mining is done ata hill named Noije Bum near Tanai Village (2621033.4100N,9643011.8800E) (e.g., Cruickshank and Ko, 2003; Grimaldi et al.,2002). Observations and photographs were taken using a Zeiss

    * Corresponding author. State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39East Beijing Road, Nanjing 210008, China.

    Contents lists availab

    Cretaceous

    els

    Cretaceous Research xxx (2014) 1e6E-mail address: caichenyang1988@163.com (C. Cai).abdominal segment (Newton et al., 2000). Although a few otherstaphylinids, including certain genera of Euaesthetinae, Paederinae,Tachyporinae and some Stenus species, have unmargined abdomen,they can be easily separated from Osoriinae by having slender,more or less falcate mandibles lacking molar lobes and concealedantennal insertions (Newton et al., 2000).

    Fossil osoriines are relatively rare, and all of them are limited tothe Tertiary (Hope, 1837; Irmler, 2003; Ortega-Blanco et al., 2013;Zhang, 1989). Zhang (1989) described a fossil oxyteline species,

    been reported. The origin and early evolutionariinae thus remain unclear.

    Herein, we report a discovery of a much obeetle (ca. 99 million years old; see details in Shnew genus from the Cretaceous Burmese ambedating of zircons, an earliest Cenomanian age (fossilized inclusions in Burmese amber is estab2012). The new fossil, about twice the ageknown Eocene fossil from India, represents the ol2001; Thayer, 2005). The subfamily Osoriinae is a very distinctivegroup among Staphylinidae, which lacks paratergites on each

    Eocene amber of India, which is regarded as the oldest known fossilof Osoriinae. Until now, no fossil osoriines of Mesozoic age haveCretaceousBurmese amber

    1. Introduction

    With more than 2083 describedrove beetle subfamily Osoriinae is tOxyteline group of subfamilies (GreThayer, 2005). Modern osoriine rovuted in all biogeographic regions ehttp://dx.doi.org/10.1016/j.cretres.2014.03.0200195-6671/ 2014 Elsevier Ltd. All rights reserved.

    Please cite this article in press as: Cai, C., HuaCretaceous Research (2014), http://dx.doi.ors and 103 genera, thest diverse group of theov and Newton, 2012;les are widely distrib-the Antarctic (Herman,

    (2003) described an extinct genus Lispinomimus Irmler, twoextinct species (Thoracophorus palaeobrevicristatus Irmler andNacaeus dominicanensis Irmler), and ve unnamed species ofgenera Liberiana Blackwelder, Osoriellus Fagel, and Neosorius Fagelfrom the Early Miocene Dominican amber. Recently, Ortega-Blancoet al. (2013) described a new genus and species, Paleosorius cam-bayensis Ortega-Blanco, Chatzimanolis and Engel, from the EarlyOsoriinaeThoracophoriniStaphylinidaelong antennae, very long maxillary palpomere 4, contiguous procoxae, and well-developed anterolateralpronotal angles. The new discovery of the oldest Osoriinae from about 99 million years not only suggestsThe oldest osoriine rove beetle from Cre(Coleoptera: Staphylinidae)

    Chenyang Cai a,b,*, Diying Huang a

    a State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology aRoad, Nanjing 210008, ChinabGraduate School, University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 10

    a r t i c l e i n f o

    Article history:Received 4 December 2013Accepted in revised form 17 March 2014Available online xxx

    Keywords:

    a b s t r a c t

    A remarkable new genusgured based on a well-prfrom Myanmar. Mesallotroincluding the protibia witcoxal cavities, and more or

    journal homepage: www.ng, D., The oldest osoriine rovg/10.1016/j.cretres.2014.03.02ceous Burmese amber

    alaeontology, Chinese Academy of Sciences, 39 East Beijing

    , China

    species, Mesallotrochus longiantennatus n. gen. n. sp., is described andrved individual in the lowermost Upper Cretaceous (Cenomanian) amberis placed in the extant tribe Thoracophorini based on its general habitus,ner edge straight, without ctenidium, exposed protrochantins, open pro-s atted body. Mesallotrochus is separated from other allied genera by the

    le at ScienceDirect

    Research

    evier .com/locate/CretRese beetle from Cretaceous Burmese amber (Coleoptera: Staphylinidae),0

  • Discovery V20 stereo microscope and a Zeiss Axio Imager 2 lightmicroscope with a digital camera attached. Photomicrographs withgreen background (Fig. 3) are taken using green uorescence aslight source attached to a Zeiss Axio Imager 2 light microscope. Thematerial has been prepared, including cut with a razor bladeand polished with sand papers with different grain sizes andwith diatomite mud. A polished slab of amber measuring3.5 mm 2.8 mm contains the beetle specimen, which (in dorsalview) is oriented at approximately a 40 angle to the surface.

    3. Systematic palaeontology

    Order: Coleoptera Linnaeus, 1758Family: Staphylinidae Latreille, 1802Subfamily: Osoriinae Erichson, 1839Tribe: Thoracophorini Reitter, 1909Subtribe: Clavilispinina Newton and Thayer, 1992

    Genus: Mesallotrochus gen. nov.

    Type speciesMesallotrochus longiantennatus sp. nov., here designated.

    EtymologyThe genus name is a combination of Meso-, meaning Mesozoic,

    and the supposed related genus Allotrochus; it is masculine ingender.

    DiagnosisSmall, slightly attened Staphylinidae with: eyes moderate,

    distinctly protruding, coarsely faceted; antennal insertions con-cealed; antennae densely setose, not clubbed, long, extending

    widest nearly at middle, with lateral carinae, anterolateral pronotalangles well-developed; elytra longer than pronotum, covering partof abdominal tergite III, with epipleural keels; protrochantinsexposed; pro- and metacoxae contiguous; mesocoxae narrowlyseparated; femoraweakly dilated, somewhat atted, with relativelydeep concave groove in ventral side to conceive tibia; tibiae veryslender, without strong spins; all tarsi 5-segmented; abdominalsegments IIIeVIII well-developed, without paratergites, tergiteswithout basolateral ridges.

    Mesallotrochus longiantennatus sp. nov. (Figs. 1e4).

    EtymologyDerived from the combination of the Latin adjectives longus and

    antennatus, meaning with (or having) long antennae.

    MaterialHolotype, NIGP157737. The fossil beetle is a completely pre-

    served adult. The type specimen is housed in the Nanjing Instituteof Geology and Palaeontology, CAS, Nanjing, China.

    OccurrenceLowermost Upper Cretaceous (ca. 99Ma) amber from the village

    of Tanai, Hukawng Valley, northern Myanmar.

    DiagnosisAs for the genus (vide supra).

    DescriptionBody: 2.86 mm long; sub-parallel, deep brown throughout.Head: relatively small, 0.43 mm long and 0.51 mm wide

    (including eyes), without lateral or dorsal neck constriction; withfour long setae at apical margin of frons; antennal insertions con-

    C. Cai, D. Huang / Cretaceous Research xxx (2014) 1e62beyond posterior margin of pronotum; maxillary palpi long, withreduced palpomere 3 and elongate article 4; pronotum transverse,Fig. 1. General habitus of Mesallotrochus longiantennatus n. gen. n. sp., holotype, NIG

    Please cite this article in press as: Cai, C., Huang, D., The oldest osoriine rovCretaceous Research (2014), http://dx.doi.org/10.1016/j.cretres.2014.03.02cealed under shelf-like corner of frons, located before a line drawnP157737. A. dorsal view; B. ventral view. Under normal light. Scale bars: 1 mm.

    e beetle from Cretaceous Burmese amber (Coleoptera: Staphylinidae),0

  • ousC. Cai, D. Huang / Cretacebefore anterior margin of eye. Eye positioned laterally. Antennaelong (Fig. 2B; 3A), 11-segmented, moniliform; antennomeres 1broad and elongate, antennomere 2 elongate, slightly narrowerthan antennomere 1, antennomere 3 gradually dilated to apex,nearly as long as antennomere 2, antennomeres 4e7 graduallywidened, antennomere 8 slightly smaller than 7 and 9, anten-nomere 10 almost in the same size and shape as 9, antennomere 11conical, 1.6 times as long as antennomere 10. Labrum and labialpalpus not observable. Mandibles with sharp apex visible. Maxil-lary palpus (Fig. 2A) relatively long, apparently 4-segmented, pal-pomere 2 longer than wide, palpomere 3 as wide as 2, but shorterthan 2, palpomere 4 elongate, about 2.8 times as long as palpomere3, glabrous.

    Thorax: Pronotum wider than head. 0.69 mm wide, 0.54 mmlong. Pronotum in dorsal view slightly narrowed from middle tobase; anterior margin concave, posterior margin nearly straight.Anterolateral angels distinctly pronounced, posterolateral angelsrectangular. Pronotum with well-developed lateral carina. Pros-ternum transverse, procoxae contiguous (Fig. 3B), with a smallprosternal process; procoxal cavities open. Pronotal hypomerondeveloped, subtriangularly produced inwards. Mesocoxae narrowlyseparated by smaller mesoventral and larger metaventral processes(Fig. 3B); metacoxae contiguous. Mesoscutellum sub-triangular,longer than wide, distinctly narrowed at anterior third. Elytraelongate, sub-parallel, 0.75 mm long and each 0.44 mm wide,

    Fig.