Cretaceous Research 63 (2016) 45e53 Contents lists available at ScienceDirect Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes A thorny, ‘anareolate’ stick-insect (Phasmatidae s.l.) in Upper Cretaceous amber from Myanmar, with remarks on diversification times among Phasmatodea * Michael S. Engel a, b, , Bo Wang c, d, Abdulaziz S. Alqarni e a Division of Entomology, Natural History Museum, 1501 Crestline Drive e Suite 140, University of Kansas, Lawrence, KS 66045-4415, USA b Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA c State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China d Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Science, Beijing 100101, China e Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia article info abstract Article history: A new fossil stick-insect (Phasmatodea) is described and figured from a male preserved in Cretaceous Received 7 January 2016 amber from Myanmar. Echinosomiscus primoticus Engel and Wang, gen. et sp. nov., is a robust, somewhat- Received in revised form compressed stick-insect bearing abundant acanthae over the head and body, and remarkably lacks an 26 February 2016 area apicalis on the tibiae. The species is described and assigned to a new, extinct subfamily of Phas- Accepted in revised form 27 February 2016 matidae s.l., as Echinosomiscinae Engel, subfam. nov. Brief remarks are made regarding the dating of Available online 3 March 2016 phasmatodean lineages, with E. primoticus providing the first reliable evidence for Euphasmatodea and even Neophasmatodea in the Cenomanian. Keywords: © Cenomanian 2016 Elsevier Ltd. All rights reserved. Euphasmatodea Holophasmatodea Neophasmatodea Phasmatidae Taxonomy 1. Introduction whereby gentle swaying gives the impression of foliage moving in a breeze (Bedford, 1978). The eggs of Phasmatodea are remarkably Insects of the order Phasmatodea are famous for crypsis, character-rich and mimic seeds, and the order is one of the few assuming diverse morphologies that allow them to mimic the with a developed ootaxonomy (Clark, 1976a, 1976b, 1978, 1979; surrounding foliage (Bedford, 1978), and their affinities among Sellick, 1988, 1997a, 1997b, 1998), making it possible to diagnose other polyneopteran lineages continues to inspire debate, either as the presence of particular clades from eggs alone. relatives to the Embiodea (Kristensen, 1975; Whiting et al., 2003; Naturally, in a group as varied as Phasmatodea, not all species Terry and Whiting, 2005; Friedemann et al., 2012) or Orthoptera can simply be lumped as either stick or leaf mimics, and there are (Hennig, 1981; Wheeler et al., 2001; Grimaldi and Engel, 2005). those, such as Trychopeplus Shelford or Oreophasma Günther that These prominent herbivores include some of the longest of extant are rather moss- or fern-like, and some Extatosoma Gray mimic insects, such as Phobaeticus chani Bragg reaching to over 56 cm in lichens (Robinson, 1969; Brock, 2001). On the other end of the length when the legs are extended (Hennemann and Conle, 2008), spectrum, some forms are more robust and although long, are often and different groups are either greatly elongate, mimetic with compressed and not so clearly stick-like. Regionally known as land twigs or sticks, hence the name stick-insect, or are broadened and or tree ‘lobsters’, such phasmatodeans are often heavily armed by leaf-like, the aptly named leaf-insects of the Phylliidae (Phyllo- thorny projections, or acanthae (acanthae do occur widely phasmatodea). This mimicry extends also into their behavior, throughout Phasmatodea), and can be at times massive, reaching up to 15 cm and with a body masses nearing 25 g, although at masses up to 65 g females of the Malaysian Heteropteryx dilatata * Corresponding author. Division of Entomology, Natural History Museum, 1501 (Parkinson, 1798) tip the scales as the heaviest of Phasmatodea Crestline Drive e Suite 140, University of Kansas, Lawrence, KS 66045-4415, USA. E-mail addresses: [email protected] (M.S. Engel), [email protected] (Brock, 1999a). Perhaps the most famous of such insects is the (B. Wang), [email protected] (A.S. Alqarni). critically endangered Dryococelus australis (Montrouzier, 1855), the http://dx.doi.org/10.1016/j.cretres.2016.02.015 0195-6671/© 2016 Elsevier Ltd. All rights reserved. 46 M.S. Engel et al. / Cretaceous Research 63 (2016) 45e53 Lord Howe Island Stick-Insect (sometimes referred to as the Lord long surface, beneath the insect, is comparatively flat, while the Howe Island Tree Lobster). Populations of this large, ‘Lazarus’ spe- opposing one is arched. The insect is oriented obliquely across the cies were decimated on Lord Howe Island by rats, becoming locally shorter axis (Fig. 1), with its face looking toward the curved rim of extinct by the 1960s, but in 2001 an isolated group of 24 individuals the oval. The legs are set alongside the body as if the animals were was rediscovered on Ball's Pyramid and it is considered the rarest of in stance, and the antennae are extended to the side and along the insects (Priddel et al., 2003; Robertson, 2006). Given their striking line of the body, although that of the left is incomplete. The morphologies and usually docile behavior, many stick- and leaf- abdomen is a bit shriveled, and the apicalmost segment partly insects are popular with zoological gardens and as pets for pri- damaged, the dorsomedial membrane torn, but preserving well vate collectors and children, and detailed guides exist to their the characteristic divided tenth tergum, albeit with the hemi- breeding and care (Brock, 1999a, 2000; Bradler and Seiler, 2012). tergites slightly twisted out of their natural position. The integu- The order is an ideal group from which to explore patterns of ment is partially cleared as preserved, and there is some Schimmel morphological evolution and convergence (e.g., Whiting et al., in places which, in combination with scattered organic debris 2003; Buckley et al., 2009), and is a textbook example of a group within the piece as well as the placement of the insect near some whereby wings are repeatedly lost and reacquired, presumably curved surfaces render various views difficult. Nonetheless, a through the turning on and off of a specific hox gene such that the remarkable amount of detail is observable, permitting a thorough genetic architecture for wings remains in place, albeit ‘dormant’, understanding of the species. even in those clades that are otherwise apterous. Parthenogenesis The mine from which the fossil was excavated is located in the abounds throughout Phasmatodea (Scali, 2009), and this repro- Hukawng Valley of Myanmar's northern state of Kachin, and near ductive mechanism appears to extend deeply in their phylogeny the village of Noije Bum, near Tainang, and westward of Myitkyina owing to its scattered phylogenetic presence across the order and (Kania et al., 2015). These Burmese amber mines have yielded well-studied occurrence in the relict genus Timema Scudder thousands of fossils of earliest Cenomanian age (Shi et al., 2012), (Sandoval et al., 1998; Schwander et al., 2011), a group from west- and represent one of the richest and oldest sources for paleobio- ernmost North America isolated into its own suborder, Time- logical information on the Upper Cretaceous. The locality has been matodea, and sister to all other extant phasmatodeans, or extensively studied and mapped by Grimaldi et al. (2002) and Euphasmatodea (Bradler, 1999; Tilgner et al., 1999). Cruickshank and Ko (2003), and the biotic diversity, largely While the Phasmatodea include over 3000 modern species and comprising insects, has been tabulated by Grimaldi et al. (2002) are particularly diverse in southern and southeastern Asia (Brock, and Ross et al. (2010), but with numerous important additions 1999b; Seow-Choen, 2000; Bragg, 2001; Otte and Brock, 2005; subsequent to these works that have expanded the crustacean Chen and He, 2008; Großer,€ 2008), their past diversity has been a (Broly et al., 2015), arachnid (Engel and Grimaldi, 2014a; Engel challenge to reconstruct. Their often large proportions and frail et al., 2016a), and insect records (e.g., Grimaldi and Engel, 2013; bodies have not lent them to ideal preservation, and when fossils Barden and Grimaldi, 2014, 2016; Dikow and Grimaldi, 2014; have been recovered they are frequently of nymphs or exception- Engel and Grimaldi, 2014b; Grimaldi and Johnston, 2014; Arillo ally fragmented. Varied Mesozoic fossils from the Jurassic and et al., 2015; Parker and Grimaldi, 2014; Vea and Grimaldi, 2015; Lower Cretaceous, many known only from isolated wings, have Delclos et al., 2016; Engel et al., 2016b, 2016c, 2016d, 2016e, been attributed to the stem group of Phasmatodea, the most 2016f; Yamamoto, 2016). notable being those of the Aeroplanidae, Aerophasmatidae, and The classification of Phasmatodea is rather muddled, with Susumaniidae (e.g., Tillyard, 1918; Sharov, 1968; Gorochov, 1993, much comparative morphological investigation and revision 1994; Ren, 1997; Gorochov and Rasnitsyn, 2002; Shang et al., necessary before a robust, stable system is achieved. The Bradley 2011; Wang and Ren, 2013; Wang et al., 2014 d the Chresmodi- and Galil (1977) system has repeatedly been found wanting (e.g., dae are no longer attributed to Holophasmatodea: