Habroblattula drepanoides
Creators: name: Wang, Tian-Tian
name: Liang, Jun-Hui
name: Ren, Dong
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Blattodea
Blattulidae
Habroblattula
Habroblattula drepanoides

description: Habroblattula drepanoides gen. et sp. nov.
Fig 1. A–B, Fig 2. A–H
Holotype. A complete specimen, No. CNU-B-LB-2006369-1.
Locatity and horizon. Yixian Formation, Upper Jurassic or Lower Cretaceous, Huangbanjiegou, Chaomidian Village, Beipiao City, Liaoning Province, China.
Additional Material. CNU-B-LB-2006305, CNU-B-LB-2006378, CNU-B-LB-2006386, CNU-B-LB- 2006389, CNU-B-LB-2006392 (Forewings); CNU-B-LB-2006301, CNU-B-LB-2006302, CNU-B-LB- 2006303, CNU-B-LB-2006304, CNU-B-LB-2006369-2, CNU-B-LB-2006390-1, CNU-B-LB-2006390-2, CNU-B-LB-2006306, CNU-B-LB-2006391 (Complete specimens); Yixian Formation, Upper Jurassic or Lower Cretaceous, Huangbanjigou, Chaomidian Village, BeiPiao City, Liaoning Province, China. CNU-B- LB-2006387, CNU-B-LB-2006380, CNU-B-LB-2006384 (Forewings); CNU-B-LB-2006372, CNU-B-LB- 2006383, CNU-B-LB-2006377, CNU-B-L-B-2006320, CNU-B-LB-2006373, CNU-B-LB-2006375, CNU- B-LB-2006381, CNU-B-LB-2006382, CNU-B-LB-385, CNU-B-LB-2006376 (Complete specimens); Yixian Formation, Upper Jurassic or Lower Cretaceous, Jianshangou, Chaomidian Village, Beipiao City, Liaoning Province, China.
Description. (Figs 1–6) Large species. Head length/width: 2.0–2.7/2.0– 2.2mm, more or less globular; antennae filiform, shorter than body length; mandibles strong with sharp dentition; maxillary palps 5-seg- Forewing elongate, elliptical, length/width=11.0–12.0mm/ 3.2–4mm, with more or less parallel margins and characteristic coloration (dark macula apically of the R and M, look like “falcate” and in the basal part of the posterior margin); Cross-veins distinct, mainly in clavus and Cu area; intercalaries pale; apex oval; costal space narrow, occupies 1/3 of the wing length; Sc straight and somewhat thickened, simple or with several simple branches (1–4) (Fig 2. D); R space taking 43.0% of wing width, R slightly curved, terminated prior to the apex, forming 12–17 branches; M reaching apex, with 3–8 veins; CuA gently curved, with 3–6 branches; CuP simple; Clavus occupies 1/3 the length of the posterior margin of the wing, anal veins numerous (6–8).
Hindwing length 10.0–11.0mm. Simple weak Sc reach 1/3 the wing length; Pterostigma present in the R1 (5–6), RS (9–11), diverged from R basally; M with 2–5 simple branches, reaching the apex; CuA with 6–9 veins; thin CuP simple straight; A1 forked; Intercalaries and cross-veins apparent, apex distinctly coloured.
Legs cursorial, colored (Figs 2. G. H). Fore legs thin compare with mid and hind legs, femora narrow, as wide (0.35mm) as tibiae; Mid legs longer than fore legs, femora (3.0 mm) shorter than tibiae (3.5 mm); tarsus (2.5mm) longer than 1/2 length of tibia; Hind legs longer than fore legs and mid legs, tibiae (5.0mm) gracile and 1.4 times as long as femora (3.5mm), tarsus (3.0mm) longer than half length of tibia. Fourth tarsal segment shorter than total length of other four segments; both femora and tibiae with long spines bearing very smooth helical ridges.
Body elongate; Cerci short, with 9 and more segments (Fig 2. B).
Remarks. Forewing venation fusion (Fig 2. F) is present in 4 of 28 specimens, mainly in different Cu and A branches. Hindwing venation fusion (Fig 2. E) is present in Cu area (2 of 28 specimens). Fusions might have been caused by some environmental factors (Vršanský 2005a).
The hindwing pterostigma and the branched SC in forewing probably represent plesiomorphic characters within the Blattulidae (Vršanský 2002a).
Variability. (Tables 1–4) The total number of the forewing veins (23–27, exclude Sc and A) meeting the forewing margin has the lowest CV (5.72). Comparatively, low CV value (8.22) is observed in R+M system (17–22). M (3–8) seems to be the most variable (CV=30.99) vein. Limited variation in the anterior part of the wing suggests enhanced flight capabilities when compared with the representatives of the Spiloblattinidae, Poroblattinidae, Mylacrididae, Caloblattinidae, Mesoblattinidae, supporting the hypothesis that the Blattulidae were active flyers (Vršanský 2000).
Variability is lower than that found in Blattula langfeldi and Elisama tsaganica possibly due to relatively small sample size (Vršanský 2003).
It is notable that the variation in hindwing is higher than that in the forewing, which is also the case for advanced Mesozocic blattulids. The higher variation in the hind wing may be caused by the regulation of the vein strength (Vršanský 2003).
The difference between left and right wings in the same individual in Blattaria is a common phenomenon in Fossil of cockroaches. It was observed in H. drepanoides, with the left forewings differing from right ones in the following characters: CV of the total number of the veins meeting the right forewing margin is slightly higher CV (5.82) than the left forewing (CV=5.64) as well as the CV of the R, M, A, R+Cu. The CV of the Cu R+M of the right forewing is a bit lower than the left forewing. It is notable that M+Cu in the right forewing (CV=12.86) is much higher than the left forewing (CV=6.77). The asymmetry between left and right wings in one specimen suggests that the specimen had limited flight capability. An appreciation of the asymmetry of the venation is very important for identifying fossil Blattaria. It clarifies which features of venation are important for identification of fossils.
Etymology: after Greak for drepanoides (falcate), refers to the forewing falcate dapple. Character of preservation. 20 complete specimens and 8 isolated forewings.
Yixian Formation is characterised by a high ratio of H. drepanoides, a colored cockroach species, possibly indicating warm and moist climate.
In the wing venation for H. drepanoides, the total number of veins (excluding SC and A) reaching the wing margin is found to be the least variable character, suggesting active flight, supported by the asymmetrical difference between left and right forewings. Higher variability of the hind wing might suggest habroblattula was an advanced genus, with vein strength control mechanisms.
Habroblattula gen. nov. is most closely related to Svabula Vršanskÿ, 2005, supporting its near the J/K boundary age.
description: Published as part of Wang, Tian-Tian, Liang, Jun-Hui & Ren, Dong, 2007, Variability of Habroblattula drepanoides gen. et. sp. nov. (Insecta: Blattaria: Blattulidae) from the Yixian Formation in Liaoning, China, pp. 17-27 in Zootaxa 1443 on pages 19-26, DOI: 10.5281/zenodo.176061