Perissoderma Xing, Shih & Ren

Xing, Changyue, Shih, Chungkun, Zhao, Yunyun & Ren, Dong, 2016, New Earwigs in Protodiplatyidae (Insecta: Dermaptera) from the Middle Jurassic Jiulongshan Formation of Northeastern China, Zootaxa 4205 (2), pp. 180-188 : 182

Perissoderma Xing, Shih & Ren gen. nov.

Type species: Perissoderma triangulum Xing, Shih & Ren sp. nov.

Diagnosis. Body small-sized, densely setose. Head relatively small, posterior margin nearly straight. Antenna with 17 antennomeres, scape broader than others. Pronotum approximately elliptical, anterior margin almost as wide as or wider than posterior margin. Abdominal segments posterior to sixth segment (counting from metacoxal base level) compacted into a short structure. Tegmina with longitudinal veins (plesiomorphy), costal margin arched. Female with exposed ovipositor. Pygidium small. Cercus long, about half (0.5‒0.6×) as long as body (plesiomorphy).

Etymology. The generic name is a combination of the Greek word of “perisso” meaning unusual- and derma (for Dermaptera ). Gender neuter.

Comparison. Perissoderma gen. nov. is differentiated from other genera in Protodiplatyidae by the following characters:

1. The size of the head in Perissoderma gen. nov. is relatively small in comparison with the pronotum (vs. large in Asiodiplatys and Longicerciata ).

2. Antenna with 17 antennomeres (vs. 17 to more than 26 in other genera).

3. Longitudinal venation on tegmina present (vs. Sinoprotodiplatys , Asiodiplatys , Microdiplatys , Turanovia , and Longicerciata without visible veins on tegmina).

4. The pronotum approximately elliptical, anterior and posterior margins convex and lateral margins rounded (vs. approximately elliptical, anterior and posterior margins subequal in width in Sinoprotodiplatys ; anterior margin of pronotum concave, posterior margin slightly convex in Dermapteron ; lateral margins almost parallel and subequal in Microdiplatys and transversely wider in Longicerciata ; trapezoidal, anterior margin almost as wide as or wider than the posterior margin in Barbderma );

5. The length ratio of cercus to body is 0.55 (vs. longer or shorter in other genera as shown in Table 1);

6. Abdominal segments posterior to the sixth segment (counting from metacoxal base level) compacted into a short structure (vs. longer but forming a particularly compact triangle in Sinoprotodiplatys ; Archidermapteron and Longicerciata with segments 1-9 [10] of subequal length, and remaining taxa in Protodiplatys , Microdiplatys , Barbderma having segments posterior to the sixth distinctly shortened but not so deeply compacted).

7. Asiodiplatys differs from Perissoderma gen. nov. and Sinoprotodiplatys zhangi in having wings forming transverse, short and wide triangles, and antenna with 22 antennomeres.

8. Perissoderma gen. nov. differs from Sinoprotodiplatys in having tegmina shorter and wider (1:2 vs 1:4) and wing longer than half tegmen (vs. several times shorter).