Cretolixon, Lohrmann & Zhang & Michalik & Blaschke & Müller & Jeanneau, 2020

Lohrmann, Volker, Zhang, Qi, Michalik, Peter, Blaschke, Jeremy, Müller, Patrick & Jeanneau, Laurent, 2020, † Cretolixon - a remarkable new genus of rhopalosomatid wasps (Hymenoptera: Vespoidea: Rhopalosomatidae) from chemically tested, mid-Cretaceous Burmese (Kachin) amber supports the monophyly of Rhopalosomatinae, Fossil Record 23 (2), pp. 215-236 : 227

Cretolixon and Rhopalosomatidae

Cretolixon is an enigmatic new genus, which can be confidently assigned to the crown group rhopalosomatids. Specifically, the presence of diagnostic characters such as a very narrow fore wing costal cell, distinct apical bristles on the basal flagellomeres, posterad paired mesosternal lobes covering the bases of the mesocoxae, laterally widened female tarsomeres, upcurved parameres, and an upcurved sting support the placement of the genus in the family. On the other hand, a placement among the two recent subfamilies is far more challenging and without a phylogenetic analysis rather difficult. Thus, we choose a conservative approach and will test the placement of Cretolixon in a future study. However, in the following, we will discuss key characters and their implications for a potential subfamily affinity in more detail (see also Figs. 9 and 10 ).

Figures

Figure 9. Some characters of Rhopalosomatidae. (a) Rhopalosomatidae, gen. et sp. indet., Burmese (Kachin) amber (ZMB; MB.I 6501), basal section of hind wing. (b) Liosphex boreus Lohrmann (in Lohrmann and Ohl, 2010), basal section of hind wing. (c) Rhopalosoma nearcticum Brues, 1943, basal section of hind wing. (d) Olixon banksii (Brues, 1922), mouthparts. (e) Liosphex longicornis Lohrmann (in Lohrmann and Ohl, 2010), mouthparts. (f) Paniscomima kilombero Lohrmann, 2011, mouthparts. (g) Paniscomima opposita Guidotti, 2007, male, paratype, head in dorsal view. (h) Paniscomima seyrigi (Berland, 1951), female, head in dorsal view. (i) Liosphex varius Townes, 1977, female, holotype, head in dorsal view. Abbreviations: ab – apical bristle; lp1,..., lp4 – labial palpomere 1,..., labial palpomere 4; mp1,..., mp6 – maxillary palpomere 1,..., maxillary palpomere 6. Panel (i) is reproduced with permission from copyright holder and was first published in Zootaxa (Lohrmann and Ohl, 2010); photo by David Wahl.

Figure 10. Distribution of the discussed characters among Rhopalosomatidae.The tree topology of the recent genera is based on Brothers and Carpenter (1993), Brothers (1999) (both: “rhopalosomatids” sister to Olixon), Guidotti (1999), and unpublished molecular data (Blaschke et al., unpublished results) (both: Olixon + (Liosphex + (Rhopalosoma + Paniscomima))).