Aneuroderma oiodes Xiong, Engel & Ren, gen. et, 2021

Xiong, Shurong, Engel, Michael S., Xiao, Lifang & Ren, Dong, 2021, New archidermapteran earwigs (Dermaptera) from the Middle Jurassic of Inner Mongolia, China, ZooKeys 1065, pp. 125-139 : 125

Aneuroderma oiodes Xiong, Engel & Ren, gen. et sp. nov.

Figs 1 , 2 , 3

Diagnosis.

As for the genus (vide supra).

Type material.

Holotype, a completely preserved female, CNU-DER-NN2021003C/P; paratype, CNU-DER-NN2021004C/P. All type material deposited in the College of Life Sciences, Capital Normal University, Beijing, China.

Locality and horizon.

Jiulongshan Formation (Middle Jurassic); Daohugou Village, Wuhua Township, Ningcheng County, Inner Mongolia, China.

Description.

Adult female, preserved in both dorsal and ventral aspects. Body with numerous setae and distinctively sculptured (densely punctate-granulose throughout, particularly on head and thorax). Total length as preserved (excluding antennae, ovipositor, and cerci) about 10.75 mm. Head medial length from clypeal apex to posterior border 1.57 mm, maximum width (across level of compound eyes) 1.56 mm, prognathous; maxillary palpus pentamerous, ca 1.33 mm long (Fig. 1E ). Antennal length 5.2 mm, with 20 elongate antennomeres; scape thick, broader than remaining antennomeres, longer than wide, length 0.31 mm, apical width 0.22 mm; pedicel shortest, length 0.17 mm; flagellomeres longer than wide and distally becoming tapered. Compound eyes large and prominent, located near posterior margin of head, compound eye length 0.72 mm; distance between compound eyes distinctly longer than compound eye length (Fig. 1E ). Ocelli absent. Pronotum approximately oval and almost as broad as posterior margin of head, medial length 1.12 mm, maximum width 1.71 mm; anterior margin 1.56 mm wide, posterior margin 1.53 mm wide, anterior margin nearly straight, posterior margin slightly convex and lateral margins convexly rounded. Tegmina well developed, without venation, length 2.41 mm, maximum width 1.39 mm, lateral margins arc-shaped, posterior margins truncate, squamata extending well beyond tegminal apex, tegmina and squamata covering abdominal terga I and II (Fig. 1C ). Femora compressed and ventrally carinulate; tibiae elongate, slender, almost as long as femora; all tarsi pentamerous (Fig. 2D ). Pretarsal claws present and simple; arolium absent (Fig. 1D ). Abdomen cylindrical, with dense, soft, short setae, lateral margins relatively convex, almost all segments wider than long with apical margins straight, abdominal length as preserved (excluding cerci) 5.38 mm, maximum width 2.41 mm. Abdomen distally with external ovipositor, length 1.64 mm. Pygidium small. Cerci 5.33 mm long, longer than one-half abdominal length, with ca 30 elongate cercomeres, margins with abundant short setae.

Etymology.

The specific epithet is the Greek neuter adjective ōiôdes (ᾠῶδες, meaning, “oval” or “egg-like”), as a reference to the ovoid pronotum.

Remarks.

The new genus is placed within Protodiplatyidae on the basis of the characteristic filiform antenna with 17-23 antennomeres; pedicel and flagellomere I subequal in size; pentamerous metatarsus; cerci elongate, slender, and multimerous; and externalized ovipositor in females.

Key diagnostic characters of Aneuroderma gen. nov. are summarized in Table 2 and compared with those of nine genera of Protodiplatyidae . Aneuroderma gen. nov. can be distinguished from Archidermapteron Vishniakova, 1980 by the posterior margin of head as wide as anterior border of pronotum, 20 antennomeres, tegmina without longitudinal veins, and hind wings extending to apex of abdominal segment II, pygidium small, 30 cercomeres, and a cercus/body ratio of 0.5. By contrast, Archidermapteron has the head narrower than the pronotum, the tegmina with longitudinal veins, hind wings extending beyond abdominal segment IV, pygidium transverse and trapeziform, and 40 cercomeres that together are slightly shorter than the body. Aneuroderma gen. nov. differs from Longicerciata Zhang, 1994 by the latter with the head broader than the pronotum, 26 antennomeres, at least 36 cercomeres, and a cercus/body ratio of 1. Aneuroderma gen. nov. differs from Barbderma Xing et al., 2016a in the number of antennomeres (20 instead of 19), and the hind wings extending to the apex of abdominal segment II, instead of segment I. Aneuroderma gen. nov. is similar to Asiodiplatys Vishniakova, 1980 in that the tegmina lack longitudinal veins and the hind wings extend to the apex of abdominal segment II, but the former differs from the latter in only 20 antennomeres (vs. 22 antennomeres), the posterior margin of the pronotum straight (vs. pronotum with shallow, broad notch anteriorly), and 30 cercomeres (vs. 40 cercomeres). Aneuroderma gen. nov. can be separated from Abrderma Xing et al., 2016b, Microdiplatys Vishniakova, 1980, Perissoderma Xing et al., 2016b, and Protodiplatys Martynov, 1925, by the following traits: (1) absence of longitudinal veins in tegmina (present in the aforementioned genera), and (2) 20 antennomeres (vs. 17 to 19 in the other genera). The new genus is readily differentiated from Sinoprotodiplatys Nel et al., 2012 by the posterior margin of the head and anterior border of the pronotum equal in width (head narrower than pronotum in the latter), 20 antennomeres, and 30 cercomeres (18 antennomeres and 20 cercomeres in the latter). Lastly, the distinctive punctate sculpture of the new genus is quite distinctive among several Archidermaptera .

Figures

Figure 1. Holotype of Aneuroderma oiodes gen. et sp. nov. CNU-DER-NN 2021003 C. A Photograph of dorsal aspect B line drawing of dorsal aspect C dorsal view of tegmina and squamata of hind wings D anterior lateral (prolateral) view of right midleg E dorsal aspect of head. Scale bars: 2.0 mm (A, B); 0.5 mm (C, D, E). The tegmina and squamata of the hind wings in C, the right midleg in D, and the head in C are photographed under ethanol.

Figure 2. Holotype of Aneuroderma oiodes gen. et sp. nov. CNU-DER-NN 2021003 P. A Photograph of ventral aspect B ventral view of head C line drawing of ventral aspect D ventral view of midleg and hindleg. Scale bars: 2.0 mm (A, C); 0.5 mm (B, D). The head in C and the right midleg and hindleg in D are photographed under ethanol.

Figure 3. Paratype of Aneuroderma oiodes gen. et sp. nov. CNU-DER-NN 2021004 C / P. A Photograph of dorsal aspect B photograph of ventral aspect. Scale bars, 2.0 mm (A, B). The body in A and B are photographed under ethanol.