Hymenoptera, Linnaeus, 1758

Ortega-Blanco, J., Rasnitsyn, A. P. & Delclòs, X., 2008, First record of anaxyelid woodwasps (Hymenoptera: Anaxyelidae) in Lower Cretaceous Spanish amber, Zootaxa 1937, pp. 39-50 : 40-41

Fossil Hymenoptera from the Spanish Lower Cretaceous

With the exception of Peñacerrada amber, Lower Cretaceous Hymenoptera are found in Spain in the lithographic limestones (Barremian in age) partly from Las Hoyas (Cuenca Province) and mainly from El Montsec (Lleida Province) (Rasnitsyn 2000b; Rasnitsyn & Ansorge 2000a, b; Rasnitsyn & Martínez-Delclòs 2000). The following families have been recorded: Xyelotomidae Rasnitsyn, 1968 , Sepulcidae Rasnitsyn, 1968 , Anaxyelidae Martynov, 1925 , Ephialtitidae Handlirsch, 1906 , Praeaulacidae Rasnitsyn, 1972 , Gasteruptiidae Ashmead, 1900 , Andreneliidae Rasnitsyn & Martínez-Delclòs, 2000 , Mesoserphidae Kozlov, 1970 , Bethylonymidae Rasnitsyn, 1975 , Sphecidae Latreille, 1802 , Scoliidae Latreille, 1802 , and possibly Bethylidae Haliday, 1833 . La Cabrua outcrop in the Montsec is the type locality of two species of the Anaxyelidae : Eosyntexis catalonicus [recte: catalonica ] Rasnitsyn & Martínez-Delclòs, 2000, and Cretosyntexis montsecensis Rasnitsyn & Martínez-Delclòs, 2000 .

In the Spanish ambers, hymenopteran individuals are frequently found, and Hymenoptera is the second most diverse and abundant group of insects ( Delclòs et al. 2007). The majority of specimens belong to the suborder Apocrita . Eight families of non-aculeate parasitic wasps are represented: Trigonalidae , Evaniidae , Megaspilidae , Scelionidae , Stigmaphronidae , Serphitidae , Mymarommatidae , and Braconidae . The specimen previously cited as a member of the Orussidae ( Delclòs et al. 2007) is not an orussid (Vilhelmsen pers. com.). Aculeata make up 4% of the Hymenoptera and belong to the Sphecidae , Chrysididae and Bethylidae families.

Álava amber is found in several outcrops of the Basque-Cantabrian Basin ( Delclòs et al. 2007). The palynological assemblage suggests an Upper Aptian-Lower Albian age for the deposit that contains the amber included in the Escucha Formation, and the presence of Inaperturopollenites dubius pollen is related to the conifer family Cupressaceae ( Barrón et al. 2001) . In the Basque-Cantabrian Basin, the Escucha Formation is divided into three sub-units which represent the regression-transgression vertical evolution of a deltaic system. Amber levels are associated with coal layers that are abundant in the middle member of the formation, coinciding with the period of maximum regression of the deltaic system ( Salas et al. 2001; Martínez-Torres et al. 2003), related to inter-distributary deltaic bay sequences, associated with the top of abandoned channels or on crevasse splay facies.

Hymenopterans included in this amber lived between a high number of anemophilous and hydrophilous plants and a low proportion of entomophilous ones. The palynological associations suggest the presence of a dense low-land wet coniferous forest (mainly of araucariaceans and cupressaceans, and with lesser presence of pinaceans and podocarpaceans) on alluvial plains, with an important under-forest of lycophytes and schizaeacean ferns, and coastal areas under xeromorphic conditions, dominated by cheirolepidiacean conifers and cyathacean and matoniacean ferns, under a wet and cold climate ( Barrón et al. 2001).