Plesioblattogryllus magnificus, Huang & Nel & Petrulevičius, 2008, Huang & Nel & Petrulevičius, 2008

Huang, Di-Ying, Nel, André & Petrulevičius, Julian F., 2008, New evolutionary evidence of Grylloblattida from the Middle Jurassic of Inner Mongolia, north-east China (Insecta, Polyneoptera), Zoological Journal of the Linnean Society 152 (1), pp. 17-24 : 18-21

PLESIOBLATTOGRYLLUS MAGNIFICUS

GEN. NOV., SP. NOV.

FIGURES 1–3

Derivation of the name: Named after the wonderful state of preservation of the type specimen.

Material: Only the holotype included ( NIGP 133701 ). The holotype is an almost complete female specimen with brownish colour, dorsally compressed, and without counterpart. The material is deposited in the Nanjing Institute of Geology and Palaeontology .

Type locality: Daohugou Village , Ningcheng County, Inner Mongolia, north-east China; Middle Jurassic , Jiulongshan Formation .

Description: Head 10.5-mm long, 7.7-mm wide, rather developed, upper surface covered with small tubercles and tiny setae; eyes 3.4-mm long, 1.9-mm wide (left one), 4.0-mm apart, in lateral position, subelliptic in shape, contracted posteriorly; three ocelli 0.6 mm in diameter at middle, olive shaped, disposed in a triangle but nearly aligned between eyes; left mandible 4.8-mm long (without tip), 2.8-mm wide at base, right mandible 5.2-mm long and 2.6-mm wide at base, both very robust, asymmetrical (problem of preservation?), left mandible with a long, curved, and sharp pointed apical tooth and three marginal teeth, first and second being strong and pointed, and third marginal tooth located near base and very blunt; lacinia c. 4-mm long and very developed, pointed at apex, with a row of dense setae in middle inner margin; preserved part of maxillary palp 4.5-mm long, developed, with five segments of distinctly increasing width forwards, covered with fine setae; labial palp 4.3-mm long, developed, with three elongated segments of nearly the same width, covered with fine setae, second segment being shorter than the other two, the last one distinctly swollen and rounded at apex; clypeus 1.2-mm long, 2.8-mm wide, strong, with the shape of a transverse ellipse; labrum 2.5-mm long, developed, slightly projected in median part of anterior edge, extending to two-thirds of the mandibles; antenna c. 15-mm long, as long as head + pronotum, its base located close to the mandible; about 24 antennomeres, first one large, second shortest, third rather long, segments 4–7 distinctly shorter than the others, segments 8–24 with a notable decreasing width, last one with rounded end, all antennomeres covered with fine setae; ecdysial distinctly visible, Y-shaped.

Pronotum 5.2-mm long medially, 5.7-mm long laterally, 9.3-mm wide, broader than head, covered with tiny setae, with middle line and large rounded lateral expansions, anterior margin slightly projected, with pronounced angles, posterior margin rounded; mesonotum 4.2-mm long, about 4.7-mm wide, contracted backwards, distinctly narrower than pronotum.

Legs all similar; femora, tibiae, and tarsi densely covered with distinct setae; fore and hind coxae visible, and rather elongate; forelegs rather sturdy, femur 6.8-mm long, 1.8-mm wide, tibia 5.7-mm long, 0.8-mm wide; median legs rather short, femur 9.2-mm long, 1.7-mm wide, tibia 6.5-mm long, 1.1-mm wide; posterior legs slender, femur 9.6-mm long, 1.9-mm wide, tibia 9.7-mm long, 0.8-mm wide, tarsi 5.0-mm long; inner margin of median tibia with three strong aligned spines; inner margin of posterior tibia with four strong aligned spines, apical end with three strong spines; all tarsi with five segments, tarsomeres 1–4 with a pair of rather large euplantulae, fifth segments rather elongate with increased width; no arolia but two claws, hind tarsal claws 0.7-mm long, strong, and rather straight, fore tarsal claws 0.9-mm long, with a large base and a strong basal tooth.

Wings partly overlapping and difficult to interpret, in particular for the anal areas; wings dark infuscate with darker spots in distal halves; preserved parts of fore and hindwings similar, but the possible differences in the anal areas are not preserved; wings hyaline; forewing 43-mm long, about 11-mm wide; costal area between subcosta (Sc) and anterior wing margin narrow, 1.0-mm wide, in all wings, with about 20 more or less sigmoidal cross-veins between Sc and anterior wing margin; costal vein reaching wing apex; vein Sc ending on anterior wing margin 3.7 mm to wing apex; radius (R) ending very close to wing apex; Sc and R closely parallel; several cross-veins in area between Sc and R, the most distal ones being oblique; base of Rs 22 mm from wing base, in basal half of wing; area between R and radial sector (Rs) rather narrow, 1.2-mm wide in its broadest part, with one or two rows of cells; Rs posteriorly pectinate, with five main branches; cubitus apex (CuA) emerging from Cu at wing base and basally fused with common stem R + media (M); R and M + CuA separating about 4 mm from wing base; M + CuA anteriorly pectinate, with first branch media anterior (MA) emerging 7 mm from its base; MA posteriorly pectinate, with three branches in its distal fourth; media posterior (MP) emerging 10 mm from base of M + CuA and apparently simple; CuA posteriorly pectinate with three long and simple branches; cubital area between M + CuA and cubitus posterior (CuP) broad, with long sigmoidal cross-veins; CuP simple; anal vein 1 (A1) posteriorly pectinate with three simple branches; A2 forked; hindwing about 40-mm long.

Abdomen 15.8-mm long, segmentation not clearly visible, first visible abdominal segment shorter than half of the second, and other visible segments with distinct lateral lobes; last segment very small with slight lateral angles; two long, parallel-sided, and straight structures corresponding to the ovipositor, c. 8.0-mm long; right cercus (?) with three visible elongate segments, second segment distinctly longer than the first one; at least 11 visible large oliveshaped eggs, c. 3-mm long, 1.5-mm wide, with several strongly developed longitudinal ridges, first egg at level of second abdominal segment, but smaller than the more distal eggs.

Figures

Figure 1. Plesioblattogryllus magnificus gen. nov., sp. nov., holotype NIGP 133701. A. Photograph of general habitus (scale bar represents 10 mm). B. Photograph of foreleg (scale bar represents 2 mm). C. Photograph of head (scale bar represents 5 mm). D. Photograph of hind leg (scale bar represents 2 mm). E. Photograph of eggs (scale bar represents 2 mm).

Figure 2. Plesioblattogryllus magnificus gen. nov., sp. nov., holotype NIGP 133701. Drawing of general habitus.

Figure 3. Plesioblattogryllus magnificus gen. nov., sp. nov., holotype NIGP 133701. Drawing of head.