Gemineurothrips microcephalus, Ulitzka, 2022

Ulitzka, Manfred R., 2022, New genera and species of Rohrthripidae (Thysanoptera: Tubulifera) from Burmese Cretaceous amber, Zootaxa 5162 (1), pp. 1-36 : 6-7

Gemineurothrips microcephalus gen. et sp. n.

( Figs 3–5 , 26, 29 )

Syntype female (MU-Fos-145/1; Figs 3–4 ). Body completely extended; right antenna bent downwards; wings closed over abdomen; right hind leg spread, others bent under body or head, respectively. Prothorax largely hidden, ventrally by a bubble and dorsally by a shiny reflective layer of air. Syntype female (MU-Fos-148/1; Figs 5 , 26, 29 ). Body slightly inclined to the right, completely extended; right wings spread; hind wing, however, bent forwards; left wings partly torn, overlapping body; legs spread except for right fore and hind leg. Left side of pronotum covered by a shiny reflective layer; mesonotum torn away.

Colour ( Fig. 5 ) of head, thorax and distal abdominal segments dark brown, rest of abdomen somewhat paler; antennae, legs and all major setae dark brown as well as wing veins and fringes; wing membrane uniformly light brown.

Head ( Figs 3 , 5 ) much longer than wide, with cheeks tapering straight towards base. One pair of long ocellar setae near the inner margin of antennal bases, projecting largely beyond the base of antennal segment III; a second pair close to the front margin of the eyes, much weaker and shorter. Postocular setae close to compound eyes; short and pointed. Compound eyes prominent; slightly prolonged ventrally. Ocelli small; on an ocellar hump; hind ocelli close to compound eyes; fore ocellus directed forwards. Antennae ( Fig. 4 ) nine-segmented; segment I long and barrel-shaped; segment II asymmetrically bent outwards, without a pedicle; III–VII with a short pedicle at base, then slightly asymmetrical inverse cone shaped and flat at distal margin; VIII spindle-shaped; IX small, cone shaped, basally broadly joined to VIII. Sensorium at segment II not visible; number of sense cones of the following segments difficult to assess, at least one outer and one inner on III–V, one inner on VI and one outer on VII. Mouth cone short but pointed; maxillary palps not visible. Pronotum wider than long, trapezoidal; anteromarginal, mediolateral and posteromarginal setae not visible, anteroangular setae short; two pairs of posteroangular setae, inner pair short and stout, outer as well as epimeral setae and a pair of coxal setae long and hair-like. Mesonotum sculptured reticulate at front margin but striate in posterior half. Metanotum long; sculpture not assessable. Fore wings ( Fig. 5 ) becoming progressively larger in distal half; with two parallel wing veins, both furnished with setae, but these stronger on second vein ( Fig. 29 ); membrane distally smooth but fore wing clavus and base of hind wings with structures interpretable as microtrichia ( Fig. 26 ). Fringe cilia straight; enlarged at base; for the most part deeply embedded into the wing membrane, on sockets only at the front margin of the hind wing. Duplicated cilia ( Fig. 29 ) present around wing tips and apical margins of fore wing; on hind margin attached in an angle towards the body. Hind wings without veins. Wing coupling system hamulo-frenate with six hamuli ( Fig. 26 ; MU-Fos-148/1 has four setiform processes at the fore wing clavus instead of two). Fore femora stout ( Fig. 5 ); with a long hairlike ventral seta; fore tibiae with a long dorsal seta each and distally with a thorn-like process; fore tarsi with a strong tooth each and with hamus with bilateral pseudunguis (see Bhatti 1998a, p. 256) of which the outer claw is conspicuously long and slender. Mid and hind legs slender; tibiae with a long dorsal seta and terminally each with three strong spines; mid and hind tarsi two-segmented, with hamus. Abdominal tergites with three pairs of setae, s1 longer than s2 and s3; without wingretaining setae; lateral setae pointed, recurved and long but delicate. Abdominal tergite I (pelta) not assessable; II without a dorsolateral suture; segment IX dome-shaped; setae s1–s3 long hair-like; s3 longest, protruding distally over tip of tube. Abdominal segment X elongated tubular, with a terminal crown of short anal setae.

Measurements. MU-Fos-145/1 (in microns): Body, length 2066. Head, length 233; largest width (across eyes) 163; width at base 95. Eyes, dorsal length 76, ventral length 82; width 57. Ocelli, diameter not measurable; distance 63. Inner ocellar setae 158, outer 32. Pronotum, length 258; width 315; anteroangular setae 50, outer (inner) posteroangular setae 189 (about 65, difficult to measure); epimeral setae 201; coxal setae 202. Pterothorax, largest width 302. Abdomen, length 1224; largest width 536 (segment III); segment X (tube), length 189; basal width 82. Setae on tergite IX, s1 245; s2 239; s3 290. Antennae, length 383; length (largest width) of segment I 56 (31), II 47 (22), III 53 (31), IV 47 (34), V 47 (34), VI 47 (31), VII 43 (22), VIII 34 (12), IX 9 (8). Sense cones, length of inner (outer) on segment III 19 (19), IV 22 (25), V 22 (22), VI 22 (–), VII – (19); basal width 4–6. Fore wings, length 1362; largest width 284.

Material studied. Two female syntypes; MU-Fos-145/1 ( Figs 3–4 ) was donated to the author by Patrick Müller and MU-Fos-148/1 ( Figs 5 , 26, 29 ) was purchased by the author on eBay from Terry Su , eBay username “burmite-miner”. Both specimens originate from amber mines in the Hukawng Valley, Kachin State, Myanmar and are deposited in the collection of the author .

Syninclusions. MU-Fos-145/1: threads of a spider’s web, small particles of plant detritus as well as many brownish droplets and bubbles. MU-Fos-148/1: a small fly (Diptera), coprolites, plant detritus and a large brown fissured layer of unknown origin.

Etymology. The species epithet microcephalus comes from the Greek words ΜΙκρός (mikrós), meaning “small”, and κεφαλή (kephalon), meaning “head”. It refers to the remarkably small head of this species ( Figs 3 , 5 ).

Figures

FIGURES 1–4. Rohrthripidae species. Adstrictubothrips mirapterus gen. et sp. n. 1–2: (1) holotype female dorsal view, indicated: constriction at the tube; (2) right wings, indicated: duplicated cilium on fore wing margin. Gemineurothrips microcephalus gen. et sp. n. syntype female (MU-Fos-145/1) 3–4: (3) dorsal view; (4) left antenna.

FIGURES 5–7. Rohrthripidae species. (5) Gemineurothrips microcephalus gen. et sp. n. syntype female (MU-Fos-148/1): dorsolateral view. Gemineurothrips peculiaris gen. et sp. n. holotype 6–7: (6) dorsal view; (7) left fore wing.

FIGURES 24–29. Thysanoptera wings. Wing coupling (f: frenulum, h: hamuli, r: retinaculum, smr: submarginal ridge, indicat- ed: microtrichia) 24–27: (24) Taeniothrips inconsequens Uzel (Terebrantia: Thripidae); (25) Elaphrothrips cf. costalimai Hood (Tubulifera: Phlaeothripidae: Idolothripinae); (26) Gemineurothrips microcephalus gen. et sp. n. (Tubulifera: Rohrthripidae); (27) Rohrthrips multihamuli sp. n. (Tubulifera: Rohrthripidae). Tubulifera fore wing duplicated cilia (green to red arrow: area with duplicated cilia) 28–29: (28) Haplothrips setiger Priesner (Phlaeothripidae); (29) Gemineurothrips microcephalus gen. et sp. n. (Rohrthripidae).