Vitisma coriacea, Sendi, 2024

Sendi, Hemen, 2024, Vitisma coriacea sp. n. (Insecta: Dictyoptera) from the mid-Cretaceous in northern Myanmar, first record of the genus in amber, Zootaxa 5437 (2), pp. 294-300 : 295-297

Vitisma coriacea sp. n. ( Fig. 1 )

urn:lsid:zoobank.org:act:F310D656-83B3-4480-A44A-B92626E3CFCD

Description (based on holotype). Adult roach of unknown sex, 6.39 mm long from head to wing apex, and 3.22 mm wide from left to right forewing (at ½ its length). Antennae filiform with tiny segments, each 0.08/ 0.02 mm long. Each segment bears tiny setae (0.02 mm long).

Pronotum somewhat flat, convex, shield-like with transverse margins, and almost as long as broad (1.22/ 2.03 mm). Meso- (1.04/ 2.53 mm) and metathorax (0.89/ 3.03 mm) distinct.

Forewings elongate (5.02/ 1.49 mm) and sclerotized, resulting in somewhat indistinct venation. Posterior margins separated, posterior margin, if present, very narrow. Coastal region probably elongate (up to ½ of wing length). R comb-like with 10 detectable veins. Distal part branched, reaching wing apex. Intercalary veins numerous. M large with at least 4 veins. CuA narrow, tertially branched with at least 3 veins. Hindwings partly arched without visible veins.

Legs cursorial and rich in spines (as in most cockroaches except advanced Umenocoleoidea ). Foretibia short (0.67/0.11), with at least 8 spines (0.20 mm long). Tarsi partly visible (0.59/ 0.07 mm) and covered with small setae (0.01 mm long). Midcoxae robust (0.98/ 0.64 mm). Femora (1.63/ 0.41 mm) with at least 8 anterior spines (0.13 mm long), and genicular spine of almost equal length (0.16 mm long). Tibia (1.8/ 0.15 mm) with at least 18 spines (0.32 mm long). Hindcoxae large (1.16/ 0.66 mm). Femur (1.65/ 0.21 mm) with at least 5 anterior spines (0.14 mm long), and one genicular spine (0.15 mm long). Tibia (1.75/ 0.21 mm) with at least 17 spines (0.45 mm long).

Holotype. SNM Z 40733 , deposited in Slovak National Museum.

Etymology. After the Latin word coriaceum, which refers to the leathery texture of the forewings.

Differential diagnosis. The species differs from other species of the genus by the absence of a white macula on the forewing and rather elongated shape of pronotum (almost as long as broad, anteriorly rounded).

Characteristics of preservation. The amber piece is honey-coloured and contains blisters, cysts and plant debris, or other biological material. The mite syninclusion belong to the Mesostigmata or Prostigmata.

The examined insect specimen is largely preserved. The left forewing is taphonomically affected (elongated near the base). Tarsi with claws are missing. Apart from the 3 basal sterna, abdominal segments and terminalia are not detectable and were probably separated during deposition. It is uncertain whether the posterior margins are detached due to the state of preservation.

Figures

FIGURE 1. Vitisma coriacea sp. n. (holotype SNM Z 40733) from Hukawng Valley, northern Myanmar amber: (A) Illustration of dorsal view of the specimen. (B) Photograph of dorsal view of the specimen. (C) Ventral view. (D) Mite syninclusion of Mesostigmata or Prostigmata. Scale bar is 1 mm.