Baryshnyala occulta, Ilger, Jan-Michael & Brauckmann, Carsten, 2011

Ilger, Jan-Michael & Brauckmann, Carsten, 2011, The smallest Neoptera (Baryshnyalidae fam. n.) from Hagen-Vorhalle (early Late Carboniferous: Namurian B; Germany), ZooKeys 130, pp. 91-102 : 92-94

Baryshnyala occulta gen. et sp. n. Fig 1 A–B2A–F

Holotype (and only known specimen).

Specimen no. WMf.N P.212999, left metathoracic wing, with slightly damaged apex and lacking wing base. Stored in the collection of the LWL-Museum für Naturkunde, Westfälisches Landesmuseum mit Planetarium in Münster (Germany).

Type locality.

Former brickyard quarry near Hagen-Vorhalle, North Rhine-Westphalia, Germany (topographic map 1: 25,000 sheet no. 4610 Hagen/Westfalen; 51°22.88'N; 007°26.77'E, ~115 m a.s.l.).

Type stratum.

Early Late Carboniferous (Early Pennsylvanian): early Bashkirian, late Namurian B, late Marsdenian, ammonoid zone R2c, Ziegelschiefer Formation.

Diagnosis.

As for the genus (due to the temporarily monospecific status). Length ≥9.6 mm.

Preservation.

The isolated wing is quite well preserved, though it lacks the proximal tenth with articulation and most of the anal area. Apical wing margin is also slightly damaged. The corrugation is easily discernible but flattened by diagenetic compression. The anterior midwing is slightly damaged by preparation marks which obscure the exact reconstruction of terminal ScP– and RA+ branches-especially whether they do or do not fuse.

Also visible in the apical area (Fig. 1), tiny prodissoconchs of young bivalves are attached to the dorsal wing membrane. These embryonic shells are common in basal Neoptera from Hagen-Vorhalle but are absent in all other Pterygota from the same locality. Most recently this has led to new interpretation of the taphonomy of the Lagerstätte.-A manuscript by Ilger is currently in review, Ilger and Brauckmann (2009) gave a short overview.-The model implies a stage of drifting along a pycnocline in a well stratified water body. During this period the corpses were affected by free-swimming bivalve larvae.

Measurements.

Preserved length: 8.7 mm; estimated length: ≥9.6 mm; maximum width (at most posterior branch of MP–): 4.2 mm. Approximated ratio length/width: ~2.3.

Description.

There is only one isolated wing known. Due to its shape and the existence of a cubito-median fold we suppose it is a metathoracic wing (Figs 1-2). Costal margin in mid-wing straight, apex well rounded. Costal area strongly pectinate with wide-standing cross-veins. ScP– simple and most likely reaching costal margin. R stem proximally thick and strong, branching in proximal quarter of wing length. RA+ simple and generally straight, terminal development not well preserved but probably reaching costal margin in distal fifth. RP– well and strongly developed, with 9 terminal branches. MP– strong, with 5 terminal branches, first branching clearly before mid-wing and fanning at basal third of wing length, posterior branches with strongly curved backwards at posterior wing margin. Strong arculus (= cross-vein between MP– and CuA+) present in proximal eighth of the wing. CuA+ slightly reduced, slightly concave in the middle part before branching, with 3 terminal branches, all very strongly curved backwards. Well developed and probably sclerotizied cubito-median fold (between MP– and CuA+) running close to CuA+, especially in the proximal part. CuP– with 3 terminal branches, CuP1- very strongly convex. First AA+ straight. A number of thin and straight cross-veins mainly in the sectors of RP– and MP– and distal of mid-wing.

Etymology.

Latin occultus, -a, -um (adjective) meaning arcane. The holotype specimen was stored for twenty years in the collection without being identified as a new species.