Chresmoda obscura is one of the most common fossil insects found in the Solnhofen Limestone (Ponomarenko, 1985). This specimen is preserved as a cast with slightly darker coloration of the body and legs, along with some calcite mineralization around the head area. However, there is limited preservation of fine anatomical detail.

Some controversy has surrounded the paleoecology of these extinct insects. Their very long legs and general body plan, similar to that of water striders, suggest the ability to skate along the water surface. However, their large size would seem to preclude such behavior. The current consensus, based on detailed analysis of their leg anatomy, is that these aquatic insects rested on floating plants or skimmed over the surfaces of ponds or lagoons (Delclos et al., 2008; Shi et al., 2019).

They differ from living water striders (family Gerridae) and do not fit into any living group of insects, though they may have been somewhat similar to walking sticks or stoneflies (Nel et al., 2004). Female individuals had wings and were capable of flight, whereas males and nymphs appear to have been wingless (Delclos et al., 2008).

At least 10 species of the genus Chresmoda have been described (Paleobiology Database, n.d.), with specimens found in Jurassic rocks of Germany and Cretaceous rocks from England, China, Spain, Mongolia, Brazil, Myanmar, and Lebanon.

References:

Delclòs, X., Nel, A., Azar, D., Bechly, G., Dunlop, J.A., Engel, M.S. and Heads, S.W., 2008. The enigmatic Mesozoic insect taxon Chresmodidae (Polyneoptera): New palaeobiological and phylogenetic data, with the description of a new species from the Lower Cretaceous of Brazil. Neues Jahrbuch fur Geologie und Palaontologie-Abhandlungen, 247(3), p. 353.

Nel, A., Azar, D., Martínez-Delclòs, X. and Makhoul, E., 2004. A new Upper Cretaceous species of Chresmoda from Lebanon-a latest representative of Chresmodidae (Insecta: Polyneoptera inc. sed.): first record of homeotic mutations in the fossil record of insects. European Journal of Entomology, 101(1), pp. 145-152. doi:10.14411/eje.2004.019.

Paleobiology Database, No date. Chresmoda. Available at: https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=175598&is_real_user=1 (Accessed: November 2024).

Ponomarenko, A.G., 1985. Fossil insects from the Tithonian „Solnhofener Plattenkalke “in the Museum of Natural History, Vienna. Annalen des Naturhistorischen Museums in Wien. Serie A für Mineralogie und Petrographie, Geologie und Paläontologie, Anthropologie und Prähistorie, 87(A), pp. 135-144.

Shi, C., Shih, C. and Ren, D., 2019. Chresmodidae–Water‐Walking Insects. Rhythms of Insect Evolution: Evidence from the Jurassic and Cretaceous in Northern China, pp. 157-163. doi:10.14411/eje.2004.019.