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Cretaceous Research 53 (2015) 48e58

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Cretaceous Research

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The first trichomyiine from Burmese Cretaceous amber (Diptera,Psychodidae, Trichomyiinae)

Dany Azar a, Diying Huang b, Chenyang Cai b, Andr�e Nel c, *

a Lebanese University, Faculty of Sciences II, Department of Natural Sciences, P.O. Box 26110217, Fanar, Fanar e Matn, Lebanonb Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of Chinac Mus�eum National d’Histoire Naturelle, Institut de Syst�ematique, Evolution, Biodiversit�e, ISYEB, UMR 7205 CNRS UPMC EPHE, CP50, 45 rue Buffon,F-75005 Paris, France

a r t i c l e i n f o

Article history:Received 27 August 2014Accepted in revised form 25 October 2014Available online

Keywords:TrichomyiinaePsychodidaeAxenotrichomyiaMyanmarAmberCretaceousCenomaniangen. nov., sp. nov

* Corresponding author. Tel. þ1 310 825 6620; fax:E-mail address: anel@mnhn.fr (A. Nel).

http://dx.doi.org/10.1016/j.cretres.2014.10.0110195-6671/© 2014 Elsevier Ltd. All rights reserved.

a b s t r a c t

A new genus and species of Trichomyiinae (Axenotrichomyia boisteli) is described herein from BurmeseUpper Cretaceous (Cenomanian) amber. This new taxon is characterized, illustrated, and its taxonomicposition is discussed. This discovery sheds new light for the understanding of the palaeobiodiversity ofthis group.

© 2014 Elsevier Ltd. All rights reserved.

1. Introduction

The Trichomyiinae is a subfamily of short-legged psychodidsthat have the radial sector with only one vein (R4þ5) between theradial and medial forks. They are found exclusively in decayingwood or tree holes filled partly with rain water (Beran et al., 2010).This cosmopolitan group is represented in extant fauna by about 85species, all included in Trichomyia Haliday, 1839 (Satchell, 1956;Duckhouse, 1965, 1978, 1980; Bravo, 1999, 2001) even if thisgenus encloses a broad range of body structures (genitalia, etc.) thatimposed the creation of different subgenera.

Other recent genera were created within Trichomyiinae likeDiplonema Loew,1845, Lepria Enderlein, 1936, and Eubonetia Vargas& Diaz Najera, 1953, but Satchell (1956) synonymized them withTrichomyia. The genus Phalaenomyia Loew, 1844 originally pro-posedwithout included species is considered by all theworkers as anomen nudum.

Duckhouse (1965) stated that two or more Trichomyia groupsare presently mixed under Trichomyia, but he considered that it

þ1 310 206 8107.

would be premature to form new genera with them. Neverthelesshe subdivided the Trichomyiinae into two groups A and B basedmainly on antenna and palp structures. Later this author consideredthat this division was made as the first step towards a phylogeneticanalysis of Trichomyia, and that neither group is monophyletic(Duckhouse, 1978), but this classification remains taxonomicallyuseful.

Trichomyiinae comprises also two monospecific Cretaceousgenera Xenotrichomyia Azar & Salam�e, in press and Axeno-trichomyia gen. nov. (herein), both having very specific wing ve-nations; plus the two monospecific Cenozoic genera EatoniscaMeunier, 1905 (Baltic amber) characterized by a very particularwing venation (Azar and Waller, 2010) and Eotrichomyia Nel et al.,2002 (Oise amber) with the samewing venation as Trichomyia, butcharacterized by male genitalia with gonostylus bearing a sharpspine as in Sycorax Haliday in Curtis, 1839 (Nel et al., 2002). Theremaining fossils, all currently attributed to Trichomyia, werediscovered in the lower Cenomanian French amber (Lak et al.,2008), the Eocene Fushun, Baltic and Saxonian amber, theMiocene Mexican amber, and the Holocene Indonesian copal(Loew, 1845, 1850; Meunier, 1905; Quate, 1961, 1963; Wang et al.,2011). The fossil evidence from the numerous species found in

Table 1Check list of fossil Trichomyiinae.

Fossil taxa Stage Deposit

Trichomyia buceras Loew, 1845 Holocene Indonesian copalTrichomyia antiquaria Quate, 1961 middle Miocene Mexican amberTrichomyia declivivena Quate, 1963Trichomyia discalis Quate, 1963Trichomyia glomerosa Quate, 1963Trichomyia mecocerca Quate, 1963Trichomyia smithi Quate, 1963Eatonisca tertiaria Meunier, 1905 Eocene Baltic & Saxonian amberTrichomyia brevicornis Loew, 1850Trichomyia concinna Meunier, 1905Trichomyia crassicornis Meunier, 1905Trichomyia decora Meunier, 1905Trichomyia distincta Meunier, 1905Trichomyia formosula Meunier, 1905Trichomyia (Diplonema) longicornis (Loew, 1850)Trichomyia nova Meunier, 1905Trichomyia procera Meunier, 1905Trichomyia pulchra Meunier, 1905Trichomyia tenera Meunier, 1905Trichomyia duckhousei Wang, Zhang & Azar, 2011 lower Eocene Fushun amberEotrichomyia electronica Nel et al., 2002 lowermost Eocene French Oise amberXenotrichomyia newjerseyiensis Azar & Salam�e, 2014 Turonian New Jersey amberTrichomyia lengleti Lak et al., 2008 lower Cenomanian French Charentes Maritimes amberAxenotrichomyia boisteli gen. et sp. nov. lower Cenomanian Amber of Myanmar

N.B. Trichomyia swinhoei Cockerell, 1917 from Amber of Myanmar belongs undoubtedly to the subfamily Sycoracinae (Lak et al., 2008). The genus Diplonemawas synonymizedwith Trichomyia (Satchell, 1956).

Fig. 1. Microphotography of dorsal habitus of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male, specimen number NIGP161238. Scale bare ¼ 1.0 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e58 49

Fig. 2. Microphotography of ventral habitus of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male NIGP161238. Scale bare ¼ 1.0 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e5850

amber suggests that this group was already diverse since at leastthe mid Cretaceous (Table 1).

Until recently, the precise age of the amber of Myanmar (Bur-mite) has been elusive. The history of this amber has beenreviewed by Zherikhin and Ross (2000), Grimaldi et al. (2002),Cruickshank and Ko (2003), and Ross et al. (2010). AfterGrimaldi et al. (2002), this amber contains probably the mostdiverse inclusions among other Cretaceous ambers. For the first 80years of its scientific study, the amber of Myanmar was generallyconsidered to be Eocene-Miocene in age. Since the nineties of thelast century, several scientists noticed the presence of someCretaceous insect groups in this amber (Zherikhin & Ross, 2000;Grimaldi et al., 2002), and a Cenomanian age was hypothesized

Fig. 3. Drawing of antenna of Axenotrichomyia boisteli gen. et s

by Grimaldi et al. (2002). Cruickshank & Ko (2003) reviewed thegeology of the Burmite deposits, and proposed a late Albian age.Recently it was possible to give an absolute age of the amber ofMyanmar based on UePb dating of zircons inside the amber (Shiet al., 2012). The absolute given age is earliest Cenomanian, orapproximately 99 Ma. A psychodid has been described from thismaterial (Trichomyia swinhoei Cockerell, 1917) and assigned togenus Trichomyia, but this assignation is largely erroneous (Laket al., 2008)

We describe herein a new genus and species (Axenotrichomyiaboisteli gen. et sp. nov.) of the first real fossil trichomyiine fly fromthe Cretaceous amber of Myanmar. This new taxon adds more ev-idence of the rich palaeodiversity for this peculiar group and, as

p. nov.; holotype, male NIGP161238. Scale bare ¼ 0.3 mm.

Fig. 4. Microphotography of detail of antenna of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male, specimen number NIGP161238; red arrows show ascoids Scalebare ¼ 0.01 mm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

D. Azar et al. / Cretaceous Research 53 (2015) 48e58 51

fossilization is an exceptional event, this group was probably asdiverse, if not more, than those of recent entomofauna.

2. Material and methods

This study is based on a single specimen from a blocNIGP161238 (male) from Burmese amber that comes fromHukawng Valley in the northern state of Kachin, Myanmar,deposited in the Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing, China. The amber piececontains several syninclusions (one psocodean and four dipterans:one Brachycera fly, two different ceratopogonid males, and oneceratopogonid female). The amber piece was prepared as pro-posed by Azar et al. (2003) between two cover slips, using Canada

Fig. 5. Drawing of detail of antenna of Axenotrichomyia boisteli gen. et sp. nov.; ho-lotype, male NIGP161238; red arrows show ascoids. Scale bare ¼ 0.1 mm.

Balsam as mounting medium. The specimen was examined undera Nikon SMZ 1500 stereomicroscope, Olympus CK 40 invertedmicroscope, and a Leitz Wetzlar compound microscope, allequipped with drawing tubes for line drawings and AmScope 9MPdigital camera. Photomicrographs with green background (Fig. 16)is taken using green fluorescence as light source attached to aZeiss Axio Imager 2 light microscope and using a confocal laserscanning microscopy (CLSM) Zeiss LSM 710. CLSM was used toproduce high resolution in-focus three dimensional images ofrelatively thick sections by targeted fluorescence. The studiedspecimen was imaged and constructed in 3D using CLSM, whichenables detailed observation without damaging. We follow thewing venational and body nomenclature of McAlpine (1981) andQuate and Vockeroth (1981), with the following abbreviations: h,humeral vein; Sc, subcosta; R1, R2, R3, R4þ5, radial veins; M1, M2,M3, median veins; CuA1, CuA2, cubital veins; A1, anal vein; r-m,radial-median cross-vein.

3. Systematic palaeontology

Order: Diptera Linnaeus, 1758Family: Psychodidae Newman, 1834Subfamily: Trichomyiinae Tonnoir, 1922Genus: Axenotrichomyia gen. nov.

Type species. Axenotrichomyia boisteli sp. nov., by monotypy andpresent designation.Etymology. The generic name is after ‘A’ in Greek for negation,‘xenos’ (îÝíï�o) ¼ strange in Greek and Trichomyia.

Diagnosis. Short legged Trichomyiinae (i.e. legs not longer thanbody), with palpi three-segmented; antennal flagellomeresslightly excentric; distinctive wing venation with Sc making asharp anglewith radius, R1 reaching wingmargin before level ofradial fork into R2 and R3, very short apical radial fork with R2

Fig.NIG

Fig. 6. Microphotography of palps of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male NIGP161238 Scale bare ¼ 0.02 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e5852

almost perpendicular to costa, M3 fused with CuA1 for a dis-tance basally, CuA2 modestly developed, male genitalia com-plex, inverted, with gonostylus bearing a strong and large claw.

Axenotrichomyia boisteli sp. nov.(Figs. 1e15)Etymology. The specific epithet is dedicated to our friend DrRenaud Boistel.Holotype. Specimen number NIGP161238 (male) (Figs 1, 2),deposited in the Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing, China.

Type locality and horizon. Lowermost Cenomanian, HukawngValley, northern Myanmar. The mining is done at a hill namedNoije Bum, near Tanai Village (26�21033.4100N, 96�43011.8800E).

Diagnosis. As for the genus (vide supra).

Description. Body 1.3 mm long (without head, because the headis bent below thorax) (Figs 1, 2). Head with vertex well-developed and bulging, 0.2 mm large, with prominent longitu-dinally elliptical compound eyes of 0.09 mm long and 0.08 mm,10 facets wide; space between eyes 0.08 mm; antenna 0.47 mmlong, with scapus and pedicel sub-elliptical (Fig. 3); 14 flag-ellomeres; first flagellomere as long as the remaining flag-ellomeres, last flagellomere well reduced and shorter than halfof flagellomeres 1e13flagellomeres slightly excentric, bearingtwo digitate and curved ascoids (Figs 4, 5); maxillary palpsthree-segmented, basal palpomere the longest and largest0.028 mm long and 0.021 mmwide, with sensory rods on inner

7. Drawing of palps of Axenotrichomyia boisteli gen. et sp. nov.; holotype, maleP161238. Scale bare ¼ 0.1 mm.

side, second one 0.022mm long and 0.014 mm large, third is theshortest, 0.018 mm long and 0.005 mm large (Figs 6, 7). Wing0.98 mm long, 0.39 mm wide (Figs 8, 9); apex of wing slightlyrounded somehow pointed; humeral vein h reaching wingmargin at 0.11mm fromwing base, subcostal vein Sc reaching Rs0.31 mm from wing base, a very week and phantom-likecrossvein relating obliquely Sc to costal margin; Rs three-branched; R1 curved inward reaching wing margin at0.71 mm distally of base of Rs; R2 and R3 fork very short,occurring at 0.78 mm distally, well after level where R1 meetswith costal margin; R2 reaching margin at 0.84 mm from wingbase; R3 reaching costal margin at 0.98 mm fromwing base; R4and R5 fused, forming R4þ5 reaching wing apex; fork of M1þ2into M1 and M2 0.49 mm distally of r-m; M1 reaching wingmargin at 0.93 mm of its base; M2 slightly shorter than M1; M3reaching wing margin at 0.78 mm from wing base; M3 fusedbasally for a distance with CuA1 creating as such a commonstalk of 0.09 mm; CuA1 reaching wing margin at 0.68 mmdistally; CuA2 moderately long, 0.63 mm long; A1 reachingposterior wing margin at 0.24 mm. Halteres 0.17 mm, stem0.11 mm, knob 0.06 mm.Thorax 0.31 mm long. Legs shorter than body. Abdomen0.47 mm long (without genitalia). Male genitalia complexinverted (torsion begins with the 8th abdominal segment andabove) (Figs 10e13) but with gonostylus of Sycorax-type, gon-ocoxite (basistylus) with a long, digitate, pointed and directedinward gonapophysis, gonostylus (dististylus) simple with longsetae, ending with an apical claw (Fig. 14), lanceolate, verystrong, and large; proximal parameres membraneous, trian-gular, with axial concavity, with ventral edge forming a ridgeconsolidating the triangular structure, and another ridge form-ing the height of the “triangle”, basal edge with its ventral halfinflated and bearing wavy ‘tentacles-like’ structures with apicalctenate knobs (Fig. 15), and dorsal corner of basal edge inflatedbearing a bunch of wavy ‘tentacles-like’ structures. Proximalparameres forming somehow a kind of sheath surroundingmembraneous tube-like distal parameres. Surstyli setose,reduced to a membrane in an arc form at base of parameres(Fig. 16); cerci indiscernible or very reduced.

Fig. 9. Drawing of wing of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male NIGP161238. Scale bare ¼ 0.5 mm.

Fig. 8. Microphotography of wing of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male NIGP161238 Scale bare ¼ 0.5 mm.

Fig. 10. Microphotography of genitalia of Axenotrichomyia boisteli gen. et sp. nov., dorsal view; holotype, male NIGP161238. Scale bare ¼ 0.2 mm.

Fig. 11. Drawing of genitalia of Axenotrichomyia boisteli gen. et sp. nov., dorsal view; holotype, male NIGP161238. Scale bare ¼ 0.1 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e5854

Fig. 12. Microphotography of genitalia of Axenotrichomyia boisteli gen. et sp. nov., ventral view; holotype, male NIGP161238. Scale bare ¼ 0.2 mm.

Fig. 13. Drawing of genitalia of Axenotrichomyia boisteli gen. et sp. nov., ventral view; holotype, male NIGP161238. Scale bare ¼ 0.1 mm.

Fig. 14. Microphotography of detail of the distylus spine of Axenotrichomyia boisteli gen. et sp. nov.; holotype, male NIGP161238. Scale bare ¼ 0.02 mm.

Fig. 15. Microphotography of detail of the parameres of Axenotrichomyia boisteli gen. et sp. nov., ventral view; holotype, male NIGP161238. Scale bare ¼ 0.07 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e5856

Fig. 16. Microphotography (using confocal laser scanning microscopy) of genitalia of Axenotrichomyia boisteli gen. et sp. nov., ventral view; holotype, male NIGP161238. Arrowsindicate the surstyli. Scale bare ¼ 0.07 mm.

D. Azar et al. / Cretaceous Research 53 (2015) 48e58 57

4. Discussion and conclusion

Axenotrichomyia boisteli gen. et sp. nov. is indubitably attributableto Trichomyiinae as evidenced by a typical trichomyiine wingstructure characterized by the radial sector with only one vein be-tween radial and medial forks, and CuA2 vein developed. This spe-cies is different from all the recent and other fossil species ofTrichomyiinae, except Xenotrichomyia, in having a very short radialfork very apical to apex of R1. Differences with Xenotrichomyia are inthe longer Sc and themale genitalia of Axenotrichomyia, especially inthe wavy ‘tentacles-like’ structures with ctenate knobs apically.

All Trichomyia species can be divided into two groups based onantennal and palpal structures: group Awith palps four-segmented,gonostylus short; and group B with palps three-segmented, gono-stylus long (Duckhouse, 1965). Axenotrichomyia resembles repre-sentatives of group B by the following characters: first flagellomereof nearly the same length of remaining flagellomeres, presence ofascoids, flagellomeres excentric, three-segmented palps with sen-sory rods on inner side, small sized wings.

5. Conclusion

The distinctive features cited before (i.e. moderately short Sc,very short radial fork, male genitalia with very specialized para-meres) justify the creation of a new genus. The discovery of thisfossil confirms that the Cretaceous was a crucial period for thehistorical evolution of the Trichomyiinae.

The fossil Trichomyiinae represents a little more than a quarterof the richness of the extant species of this subfamily. As

fossilization is a rare phenomenon even for Trichomyiinae that livein close relation with trees, it is probable that this group was evenmore diverse in the Cretaceous, maybe even more diverse thannowadays.

Acknowledgments

We would like to thank National Basic Research Program ofChina (2012CB821903), Outstanding Youth Foundation of JiangsuProvince (BK 2012049), and the National Natural Science Founda-tion of China (91114201) for fund supporting. This paper is acontribution to the team project “Biodiversity: origin, structure,evolution and geology” leaded by DA and awarded by the LebaneseUniversity.

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