Gemineurothrips peculiaris, Ulitzka, 2022

Ulitzka, Manfred R., 2022, New genera and species of Rohrthripidae (Thysanoptera: Tubulifera) from Burmese Cretaceous amber, Zootaxa 5162 (1), pp. 1-36 : 7-9

Gemineurothrips peculiaris gen. et sp. n.

( Figs 6–7 , 36 )

Sex not determinable, as abdominal segments VII–X are lacking ( Fig. 6 ). Body distended; left wings spread, right wings overlapping body, wing tip of left fore wing broken off; legs spread.

Colour ( Fig. 6 ) uniformly brown, including antennae and legs; all major setae dark as well as wing veins (including costa) and fringes; wing membranes ( Figs 6–7 ) with pronounced light brown wrinkles and dots of primary surface patterns (see Bhatti 1991, 1998c and Ulitzka 2019), hind wings with a paler streak along anterior margin.

Head ( Figs 6 , 36 ) wider than long; protruding at anterior margin over base of antennae. Cheeks slightly rounded and tapering towards base; with three pairs of weak setae. One pair of stout ocellar setae near the inner margin of antennal bases, their length protruding beyond base of antennal segment II; 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 small; prolonged ventrally. Hind ocelli close to compound eyes; fore ocellus directed forwards. Antennae nine-segmented; segment I 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 tiny and style-shaped. 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 bluntly pointed, reaching back to fore margin of ferna. Maxillary stylets ( Fig. 36 ) far apart and barely retracted into the head capsule. Maxillary palps two-segmented. Pronotum ( Figs 6 , 36 ) wider than long, trapezoidal; anteroangular, anteromarginal and mediolateral setae short, posteromarginal setae stout; two pairs of posteroangular setae, inner ones short and stout, outer as well as epimeral setae and a pair of coxal setae long and hair-like. Mesonotum weakly sculptured reticulate at front margin, smooth posteriorly of campaniform sensilla. Metanotum not assessable. Fore wings ( Fig. 7 ) becoming progressively larger in distal half; with two parallel wing veins; both furnished with stout setae, these stronger on second vein; membrane without microtrichia. Fringe cilia ( Fig. 7 ) 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 present around wing tips and apical margins of fore wing; on hind margin attached in an angle towards the body. Hind wing without microtrichia and without any veins. Wing coupling system hamulo-frenate; with a series of four hamuli at anterior margin close to base of hind wing. Fore femora stout ( Fig. 6 ); with long hairlike ventral seta; fore tibiae distally with a thorn-like process; fore tarsi with a strong tooth and a hamus with bilateral pseudunguis (see Bhatti 1998a, p. 256). Mid and hind legs slender; tibiae with one 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 wing-retaining setae; lateral setae pointed, recurved and long but delicate. Abdominal tergite I (pelta) not assessable; II without a dorsolateral suture.

Measurements. MU-Fos-142/1 (in microns): Length, head to abdominal segment VI 1683. Head, length 167; largest width (across eyes) 216. Eyes, dorsal length 98, ventral length 137; width 78. Hind ocelli, diameter 29; distance between the hind ocelli 127. Inner ocellar setae 127, outer 39. Pronotum, length 451; width 675; anteromarginal setae 29, anteroangular setae 20, mediolateral setae 29, outer (inner) posteroangular setae 294 (78), posteromarginal setae 147; epimeral setae about 210 (difficult to measure), coxal setae 233. Pterothorax, largest width 686. Abdomen, largest width 843 (segment IV); Antennae, length 399; length (largest width) of segment I 62 (56), II 50 (50), III 50 (47), IV 43 (47), V 47 (43), VI 48 (34), VII 48 (25), VIII 40 (9), IX 11 (3). Sense cones, length of inner (outer) on segment III 22 (19), IV 22 (25), V 22 (22), VI 28 (–), VII – (16); basal width 4–6. Fore wings, length 1195; largest width 274.

Material studied. Holotype MU-Fos-142/1 ( Figs 6–7 , 36 ); inclusion in Burmese amber from Hukawng Valley, Kachin State, Myanmar; donated by Patrick Müller and deposited in the author’s collection.

Syninclusions. Small remnants of another arthropod, fungal hyphen, plant detritus and countless tiny brownish droplets.

Etymology. The species epithet peculiaris comes from the same Latin word meaning “peculiar”. It refers to the unusual fore wings of this species ( Fig. 7 ).

Differential diagnosis. The two species in this genus are already distinguished by their visual appearance. G. peculiaris is more robust, with a much broader head and thorax. The most striking difference, however, concerns their antennae. In G. microcephalus they are slender with the median segments much longer than wide and pedicellate, whereas in G. peculiaris they are short and stout.

Figures

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 35–38. Line drawings of Rohrthripidae. Head, mouthparts and prothorax (md: mandibula, mx: maxillary stylets) 35–37: (35) Adstrictubothrips mirapterus gen. et sp. n. holotype female; (36) Gemineurothrips peculiaris gen. et sp. n. holotype (spa: posteroangular setae, left broken off and lying close to coxa; scx: coxal setae); (37) Rohrthrips rhamphorhynchus sp. n. holotype. (38) Rohrthrips multihamuli sp. n. holotype; left antenna, segment numbers in Roman numerals, indicated: ventral projections on segments V–VII (cs: campaniform sensillum, uncolored trichomes indicate presumptive sense cones).