Nigropterix cummingi, Sendi, 2024

Sendi, Hemen, 2024, Nigropterix cummingi sp. n., an umenocoleid (Insecta: Dictyoptera) from mid-Cretaceous northern Myanmar amber, Zootaxa 5424 (4), pp. 476-482 : 478-480

Nigropterix cummingi sp. n. ( Fig. 1 )

ZooBank code. urn:lsid:zoobank.org:act:B0D98387-7252-4293-A972-C991AD673082

Autapomorphies. Punctured ovipositor with setae, wide paranotalia.

Symplesiomorhies with standard Blattaria . Paranotalia present

Description (based on holotype). Adult female, 8.86 mm from head to end of abdomen, and 3.21 mm wide. Head transverse in dorsal view (1.78/ 0.52 mm) with large bulging compound eyes (0.33/ 0.37 mm), protruding from pronotum. Antenna with 34 visible segments (0.06/ 0.12–0.18/ 0.04 mm). Distal segments are thinner than proximal one. It is only about half as long as the body.

Pronotum (1.46/ 2.60 mm) flattened, broadest posteriorly (broader than head) with oblique corners and darkly coloured, except translucent wide paranotalia.

Forewings elongate (7.31/ 1.87 mm), reaching (overlapping in repose) to the end of ovipositor, and strongly sclerotized. Posterior margin almost straight, anterior margin convex with sparse minute setae ( Fig. 1d ). Apex slightly rounded. Colouration dark, except in subcostal area. It consists of minute setae (0.03 mm long), which are formed in horizontal, somewhat irregular rows of bulges, which have small pits where the setae grow from ( Fig. 1e ). Venation somewhat traceable with one R vein almost reaching wing apex, presumably two M veins dichotomised near the apex, and two CuA veins branched centrally.

Hindwings membranous with minute seta (0.02 mm long), and overlapping forewings and abdomen (7.29/ 3.03 mm). Sc reaching ½ of anterior margin. R veins reduced and divided into R1 and Rs. R1 with one visible branch, Rs with one detectable vein. M partially preserved with only one visible straight vein. Pterostigma not visible. CuA branched with at least 3 visible veins. A branched with at least 4 visible veins, two of which are part of the vannus and folded under the hindwings.

Legs standardly cursorial and robust. Midfemur partially preserved (0.38 mm wide). Tibiae (2.46/ 0.31 mm) with abundant spurs (0.34 mm long). Tarsi divided into 5 segments (0.83/ 0.11; 0.28/ 0.11; 0.12/ 0.11; 0.09/ 0.06; 0.24/ 0.12 mm). Tarsal claw partially preserved (0.16 mm long) with arolium (0.14 mm in diameter), last 3 segments are recognisable.

Abdomen somewhat narrow (2.11 mm wide) with a row of setae between the cerci (0.07 mm long). Cerci ( Fig. 1f ) striated with at least 8 segments (0.11/ 0.12; 0.17/ 0.17; 0.19/ 0.22; 0.12/ 0.17; 0.12/ 0.12; 0.12/ 0.08; 0.12/ 0.06; 0.12/ 0.05 mm), with abundant setae (0.10 mm long). Ovipostor robust, protruding (0.56/ 0.25 mm), possibly type 2 ( Hörnig et al. 2018). It is punctured on the surface with small minute setae (0.05 mm long) ( Fig. 1g ) and with a row of long setae laterally (0.8 mm long). Valves are tapering towards its apex, and posteriorly separated.

Holotype. Adult ♀, SNM Z 40731 .

Derivation of name. The species is named after the entomologist Royce Cumming, who contributed to the study of Umenocoleidae by providing several spectacular specimens from Burmese amber.

Differential diagnosis. The specimen differs from Nigropterix angustata by the parallel M, and R area with numerous cross-veins.

Remarks. The specimen is classified within the genus Nigropterix because it has dark coloured forewings with translucent subcostal area, and hindwing with narrow CuA. In addition, the texture of the forewings (formed by irregular rows of bulges) is similar to Alienopterix, Archaeospinapteryx and Poikiloprosopon. The pronotum is widened and shield-like, somewhat similar to Perspicuus and Jantaropterix , but more pronounced. The triangular shaped pronotum without reduced paranotalia, and shortened punctured ovipositor with small minute setae on the surface are probably apomorphic, and not observed in other umenocoleids. Legs are cursorial and robust, standard as in most cockroaches.

Character of preservation. The amber sample has a honey-yellow colour with numerous small syninclusions, probably detritus and possibly Chlamydomonas hanublicanus cysts ( Hinkelman & Vršanská 2020). The adult umenocoleid is almost completely preserved, except parts of the legs, distal cercal segments, and antennae are missing. Details of the forewing venation are barely visible due to strong sclerotization of the wings. Details of the head (e.g. ocelli, palpomeres) cannot be recognised due to the state of preservation.

Figures

FIGURE 1 Nigropterix cummingi sp. n. from Burmese amber of Hukawng Valley, North Myanmar, holotype (SNM Z 40731). A: Illustration of dorsal view. B: Photograph of the dorsal view. C: Photograph of the ventral view. D: Right forewing of the specimen. E: Detail of the forewing. F: Detail of terminalia with characteristic chaetotaxy. G: Detail of the ovipositor. Scale bar is 1mm.