BLATTODEA (COCKROACHES)

Grimaldi, David A., Sunderlin, David, Aaroe, Georgene A., Dempsky, Michelle R., Parker, Nancy E., Tillery, George Q., White, Jaclyn G., Barden, Phillip, Nascimbene, Paul C. & Williams, Christopher J., 2018, Biological Inclusions in Amber from the Paleogene Chickaloon Formation of Alaska, American Museum Novitates 2018 (3908), pp. 1-37 : 20

BLATTODEA (COCKROACHES)

Figure 7A

Two pieces of amber, AMNH WH-12 and AMNH WH-11, contain fragmentary remains of small roaches, probably nymphs. WH-12 contains a portion of one leg: apical portion of the femur and the entire tibia and tarsus. The tibia has 18 spinelike setae (including a pair of apical tibial spurs), in roughly four longitudinal rows. WH-11 contains portions of three legs and an antenna, all very dark and surrounded by a dark reddish “halo” of pyritization/oxidation. One leg is preserved as a portion of a femur; the tarsi and portions of the tibia are preserved for the other two legs. Approximately 30 filiform flagellomeres are preserved; the basal ones short (lengths about twice the width), gradually increasing in length distad to about five times the width. Leg segments of WH-11 are shorter than in WH-12, and tarsomere four has a long ventral lobe. Thus, there appears to be two taxa of roaches. Though these specimens cannot be identified to family or superfamily, they are clearly Blattodea based on the antennal structure and the tibial spines, which further have minute serrations on the ventral margin.

The fossil record and natural history of roaches are reviewed by Grimaldi and Engel (2005). The natural distribution of Blattodea worldwide is almost entirely tropical to warm temperate; pest species reach higher latitudes in association with human habitations. Of the 69 species of roaches in North America, 24 are introduced from other regions, and only three native species ( Parcoblatta pensylvanica , P. uhleriana , and P. virginica ) have distributions that extend into southernmost Ontario and Québec (Vickery and McKevan, 1985; Atkinson et al., 1991). The roaches are the most obvious example in Chickaloon amber of a taxon that has retreated from high northern latitudes.

Figures

FIG. 7. Various insect inclusions. A. AMNH WH-12, with legs from a roach (Blattodea), and the legs and distal portions of two wings from a caddisfly (Trichoptera). B. AMNH LC-A4, nymph of Heteroptera (Hemiptera). C, D. AMNH LC-B6, nymphal thrips (Thysanoptera), habitus (C) and detail of antennae (D). E. AMNH WH-3, with inclusion of entire male Chironomidae: Tanypodinae, and juvenile spider.