Cretaceous Research 69 (2017) 56e61

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Cretaceous Research

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A new crown wasp in Cretaceous amber from Myanmar (Hymenoptera: Stephanidae)

* Michael S. Engel a, b, c, , Diying Huang d 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 Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA d State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China article info abstract

Article history: A third species of Cretaceous crown wasps (Euhymenoptera: Stephanoidea) is described and figured from Received 8 August 2016 a male preserved in Upper Cretaceous amber from the Hukawng Valley of northern Myanmar. Phor- Received in revised form iostephanus exilis Engel and Huang, gen. et sp. nov., is generally plesiomorphic relative to the subfamilies 24 August 2016 Electrostephaninae and Stephaninae, and shares many features with the relict Schlettereriinae. However, Accepted in revised form 26 August 2016 in many respects the fossil is aberrant and therefore classified in its own tribe, Phoriostephanini Engel Available online 27 August 2016 and Huang, trib. nov., most notably for the more complete wing venation, a generally smooth integu- ment, and the absence of the usually distinctive coronal tubercles. Keywords: © Cenomanian 2016 Elsevier Ltd. All rights reserved. Euhymenoptera Schlettereriinae Parasitoid Stephanoidea Taxonomy

1. Introduction Unfortunately, Stephanidae have a sparse representation in the fossil record. Engel et al. (2013) summarized the known fos- Crown wasps (Stephanidae Leach, 1815) comprise a family of sils, noting that all, with one exception, are preserved as in- parasitoid Hymenoptera of approximately 350 extant species in 11 clusions in amber, and mostly from the mid-Eocene or Eocene- genera (Aguiar et al., 2013). In most analyses the stephanids occupy Oligocene boundary (Cockerell, 1906; Brues, 1933; Aguiar and an auspicious position as the putative surviving sister group to the Janzen, 1999; Engel, 2005; Engel and Ortega-Blanco, 2008). Two remainder of the Apocrita (Sharkey et al., 2012; Mao et al., 2015), species have been documented in Upper Cretaceous amber d one and thereby represent a lineage of putatively ancient derivation species in Turonian amber from New Jersey (Engel and Grimaldi, among the parasitoid Euhymenoptera (Grimaldi and Engel, 2005). 2004), and another in Cenomanian amber from Myanmar (Engel Species are parasitoids of wood-boring beetles and wood wasps, a et al., 2013). A species described as a stephanoid from Fushun biology plesiomorphic for Euhymenoptera. Individuals are easily amber (Hong, 2002) is assuredly a braconid, the wing venation recognized by their elongate, slender bodies with a globular head being of that family and the photograph of the holotype showing projected forward from a rather pronounced pronotal collar. The an absence of teeth on the metafemora. Similarly, a wasp head of these wasps, like that of Orussidae Newman, 1834, bears on attributed to Stephanidae from the Choshi amber of Japan its vertex and upper frons a series of tubercles (resembling a (Fujiyama, 1994), is not of this family as evidenced by the wing ‘crown’, hence the common name) used in aiding movement of the venation, simple legs, presence of tarsal plantulae, and presence wasp through the chambers of its host as it emerges. of a frontal prominence over the antennae. Here we expand upon the meager Mesozoic diversity of the family by documenting a new species from Burmese amber (Fig. 1). The new species is * Corresponding author. Division of Entomology, Natural History Museum, 1501 remarkable in many traits and differs considerably from other Crestline Drive e Suite 140, University of Kansas, Lawrence, KS 66045-4415, USA. stephanids, most notably in the absence of the typical ‘crown’ on E-mail addresses: [email protected] (M.S. Engel), [email protected] the vertex. (D. Huang). http://dx.doi.org/10.1016/j.cretres.2016.08.014 0195-6671/© 2016 Elsevier Ltd. All rights reserved. M.S. Engel, D. Huang / Cretaceous Research 69 (2017) 56e61 57

Fig. 1. Photographs of holotype (NIGP 164783) male of Phoriostephanus exilis Engel and Huang, gen. et sp. nov., in Burmese amber. A, Dorsal view. B, Ventrolateral oblique view.

2. Material and methods mapped by Cruickshank and Ko (2003) provide details on the amber deposit, including a map of the mines, while Shi et al. (2012) A single male wasp was located in a small cabochon of Burmese have provided a radiometric date for the amber of approximately amber (Fig. 1), of approximately 8.3 mm diameter and 4.2 mm 98.8 million years, or lowermost Cenomanian. All nomenclatural depth. Owing to the position of the wasp, only one of the larger decisions established in this work have been registered in ZooBank rounded surfaces could be polished flat, as well as only a single under LSID urn:lsid:zoobank.org:pub:26A2FBCF-7198-44D0-9F95- edge dorsal to the wasp. Otherwise, the anterior and posterior ends 08544A59E92D. of the wasp's body are located rather close to the curved edge of the cabochon. This leaves somewhat distorted views, owing to curva- 3. Systematic palaeontology ture of the amber surfaces, from some directions. Given that flat surfaces are positioned above and ventrolateral to the wasp, most Family Stephanidae Leach, 1815 details can be observed without difficulty. Where necessary, a small Subfamily Schlettereriinae Orfila, 1949 drop of glycerine was placed on the amber and covered by a glass Phoriostephanini Engel and Huang, trib. nov. coverslip. This eliminated most optical distortion while minimizing Type genus: Phoriostephanus Engel and Huang, gen. nov. any long-term conservation impact on the amber piece. The specimen was studied with an Olympus SZX-12 stereomi- Diagnosis. Male stephanids with head globose, with massive croscope, measured with an ocular micrometer and drawn with a compound eyes (Figs. 1, 2B); vertex reduced, without coronal ru- camera lucida attached to the same microscope. For the de- gosities or tubercles (Fig. 2B); ocelli large, lateral ocelli nearly scriptions, morphological terminology is adapted from that out- touching compound eyes; vertex posterior to compound eyes lined by Huber and Sharkey (1993) and Sharkey and Wharton short, about as long as ocellar diameter; face without striae, (1997). Photographs of the holotype were taken with a Canon 7D costae, or rugosities (Fig. 2A); labial palpus with 3 palpomeres digital camera affixed to an Infinity K-2 lens, and all were shot (the possible presence of an exceedingly minute, basal palpomere through a glass coverslip and drop of glycerine to eliminate as cannot be excluded, which would give a total count of four pal- much optical refraction as possible. The amber locality has been pomeres), individual palpomeres short, apicalmost palpomere Download English Version: https://daneshyari.com/en/article/4746681

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