Abstract
Leptoomus janzeni, n. gen. and n. sp., is described from 5 females and 2 males in 7 pieces of Baltic amber. An enlarged acropleuron forming the entire mesopleuron places the taxon within Eupelmidae, Tanaostigmatidae or Encyrtidae (Chalcidoidea), but it has a unique combination of features that differentiates it from extant members of these families. Its structural features are compared with those that characterize the three families and it is postulated to be the sister group of Tanaostigmatidae sensu stricto + (Cynipencyrtus + Encyrtidae) based on relative structure of its pronotum, prepectus and mesothoracic spiracle, and retention of two other putative symplesiomorphies, the presence of complete furrowlike notauli and a protibial apical spicule. Conflicting character states indicate other possible relationships, including a sistergroup relationship with Cynipencyrtus + Encyrtidae based on transverse-triangular axillae and a flagellum having only seven funicular segments, or with Tanaostigmatidae s. s. based on presence of an externally visible prepectal pouch, or possibly forming a monophyletic group with Tanaostigmatidae s. s. + Cynipencyrtus based on combined acropleuralmetacoxal structure. Several features support the monophyly of Tanaostigmatidae s. s., that is excluding Cynipencyrtus and Leptoomus, but these two genera are both classified in Tanaostigmatidae sensu lato until relationships are resolved more conclusively. Features possessed by different members of Neanastatinae (Eupelmidae) suggest that this subfamily may be closely related to Tanaostigmatidae s. l. + Encyrtidae, but possible relationships of Tanaostigmatidae s. s. are also discussed if its enlarged acropleuron and other skeletomusculature features associated with jumping are convergent to similar features in the other taxa.References
Bou…ek, Z. (1988) Australasian Chalcidoidea (Hymenoptera). A Biosystematic Revision of Genera of Fourteen Families, with a Reclassification of Species. CAB International Institute of Entomology, The Cambrian News Ltd., Aberystwyth, 832 pp.
Clausen, C.P. (1927) The bionomics of Anastatus albitarsis Ashm., parasitic in the eggs of Dictyoploca japonica Moore (Hymen.). Annals of the Entomological Society of America, 20, 461–472.
Clausen, C.P. (1940) Entomophagous Insects. McGraw Hill, New York, London, 688 pp.
Dzhanokmen, K.A. (1994) Comparative morphology of pteromalid head capsule (Hymenoptera, Chalcidoidea, Pteromalidae). Russian Entomological Journal, 3, 109–121.
Dzhanokmen, K.A. (2000) Phylogenetic relations between Palaearctic Pteromalidae (Hymenoptera, Chalcidoidea) subfamilies. Zoologicheskiy Zhurnal, 79, 564–571.
Gibson, G.A.P. (1986) Mesothoracic skeletomusculature and mechanics of flight and jumping in Eupelminae (Hymenoptera, Chalcidoidea: Eupelmidae). The Canadian Entomologist, 118, 691–728.
Gibson, G.A.P. (1989) Phylogeny and classification of Eupelmidae, with revision of the world genera of Calosotinae and Metapelmatinae (Hymenoptera: Chalcidoidea). Memoirs of the Entomological Society of Canada, 149, 1–121.
Gibson, G.A.P. (1995) Parasitic wasps of the subfamily Eupelminae (Hymenoptera: Chalcidoidea: Eupelmidae). Memoirs on Entomology International, 5, i–v + 421 pp.
Gibson, G.A.P. (1997) Chapter 2. Morphology and terminology. In: Gibson, G.A.P., Huber, J.T. & Woolley, J.B. (Eds.), Annotated Keys to the Genera of Nearctic Chalcidoidea (Hymenoptera). NRC Research Press, Ottawa, pp. 16–44.
Gibson, G.A.P., Heraty, J.M. & Woolley, J.B. (1999) Phylogenetics and classification of Chalcidoidea and Mymarommatoid–a review of current concepts (Hymenoptera, Apocrita). Zoologica Scripta, 28, 87–124.
Gibson, G.A.P., Read, J. & Huber, J.T. (2007) Diversity, classification and higher relationships of Mymarommatoidea (Hymenoptera). Journal of Hymenoptera Research, 16, 51–146.
Heraty, J.M., Woolley, J.B. & Darling, D.C. (1997) Phylogenetic implications of the mesofurca in Chalcidoidea (Hymenoptera), with emphasis on Aphelinidae. Systematic Entomology, 22, 45–65.
Ishii, T. (1928) The Encyrtinae of Japan. I. Bulletin of the Imperial Agricultural Experiment Station of Japan, 3, 79–160.
Janzen, J.-W. (2002) Arthropods in Baltic amber. Ampyx-Verlag Dr. Andreas Stark, Halle, 167 pp.
LaSalle, J. (1987) New World Tanaostigmatidae (Hymenoptera, Chalcidoidea). Contributions of the American Entomological Institute, 23, 1–181.
LaSalle, J. & LeBeck, L.M. (1983) The occurrence of encyrtiform eggs in Tanaostigmatidae (Hymenoptera: Chalcidoidea). Proceedings of the Entomological Society of Washington, 85, 397–198.
LaSalle, J. & Noyes, J.S. (1985) New family placement for the genus Cynipencyrtus (Hymenoptera: Chalcidoidea: Tanaostigmatidae). Journal of the New York Entomological Society, 93, 1261–1264.
Noyes, J.S. (1997) Chapter 8. Encyrtidae. In: Gibson, G.A.P., Huber, J.T. & Woolley, J.B. (Eds.), Annotated Keys to the Genera of Nearctic Chalcidoidea (Hymenoptera). NRC Research Press, Ottawa, pp. 170–320.
Noyes, J.S. (2000) Encyrtidae of Costa Rica (Hymenoptera: Chalcidoidea), 1. The subfamily Tetracneminae, parasitoids of mealybugs (Homoptera: Pseudococcidae). Memoirs of the American Entomological Institute, 62, 1–355.
Noyes, J.S. (2003) Universal Chalcidoidea database. Available from http://www.nhm.ac.uk/research-curation/projects/chalcidoids [accessed 11 June 2007].
Noyes, J.S. & Hayat, M. (1984) A review of the genera of Indo-Pacific Encyrtidae (Hymenoptera: Chalcidoidea). Bulletin of the British Museum (Natural History), 48, 131–395.
Peck, O. (1951) Superfamily Chalcidoidea. In: Muesebeck, C.F.W., Krombein K.V. & Townes H.K. (Eds.), Hymenoptera of America north of Mexico - synoptic catalog. Agriculture Monographs, U.S. Department of Agriculture, 2, 410–594.
Rasplus, J.Y., Kerdelhué, C., Clainche, I. le & Mondor, G. (1998) Molecular phylogeny of fig wasps. Agaonidae are not monophyletic. Comptes Rendus de l'Academie des Sciences, Paris (III) (Sciences de la Vie), 321, 517–527.
Simutnik, S.A. (2002) A new genus of encyrtid wasps (Hymenoptera, Chalcidoidea, Encyrtidae) from Late Eocene Rovno amber (Ukraine). Vestnik Zoologii, 36, 99–102.
Tachikawa, T. (1963) Revisional studies of the Encyrtidae of Japan (Hymenoptera: Chalcidoidea). Memoirs of Ehime University., Sect. VI (Agriculture), 9, 1–264.
Tachikawa, T. (1973) Discovery of the hosts of Cynipencyrtus bicolor Ishii and Microterys tarumiensis Tachikawa (Hymenoptera: Chalcidoidea - Encyrtidae). Transactions of the Shikoku Entomological Society, 11, 133–134.
Tachikawa, T. (1978) A note on the genus Cynipencyrtus Ishii (Hymenoptera: Chalcidoidea - Encyrtidae). Transactions of the Shikoku Entomological Society 14, 69–71.
Trjapitzin, V.A. (1963) A new hymenopteran genus from Baltic amber. Palaeontological Journal, 3, 89–95. (In Russian.)
Trjapitzin, V.A. (1977) The characteristic features of the morphology of adult encyrtids (Hymenoptera, Chalcidoidea, Encyrtidae) and their systematic significance. Trudy Vsesoyuznogo Entomologicheskogo Obshchestva, 58, 145–200. (In Russian.)