Myanmarothrips pankowskiorum, Ulitzka, 2018

Ulitzka, Manfred R., 2018, A first survey of Cretaceous thrips from Burmese amber including the establishment of a new family of Tubulifera (Insecta: Thysanoptera), Zootaxa 4486 (4), pp. 548-558 : 551-552

Myanmarothrips pankowskiorum sp. n.

( Figs 1–8)

Female: Colour uniformly dark brown including antennae and legs; all major setae dark as well as wing veins and fringes; fore wings ( Fig. 7) shaded brownish, hind wings ( Fig. 8) transparent.

Head ( Fig. 3) wider than long, constricted behind compound eyes but with cheeks swollen and roundly convergent to the base; cheeks irregularly furnished with small setae; with three pairs of ocellar setae (III anterior to the ocellar triangle). Eyes large, their front margin protruding over base of antennae, triangularly tapering on ventral side. Vertex with six postocular setae, s1 and s5 longer and stronger than the others, s 6 in most specimens strongly curved inwards. Antennae ( Fig. 3) with segments IV–IX distinctly more slender than basal segments; all segments with rings of microtrichia; III with a circular and IV with a tiny transversal and kidney-shaped distal sensorium. Mouth cone short; maxillary palps long, three-segmented; labial palps not visible. Pronotum ( Fig. 3) wider than long; front margin with 14–16 setae directed anteriorly, lateral margins with about 10 setae; hind margin with about 30 setae directed posteriorly and with one pair of strong posteroangular setae; pronotal plate regularly covered with many discal setae. Mesonotum transversally striate with rows of microtrichia; metanotum—as far as assessable—reticulate. Mesothorax (mesopleura?) laterally with a pair of strong setae bent to the front ( Fig. 2). Fore wings ( Fig. 7) with microtrichia, distally softly pointed; with four cross veins clearly seen in one specimen (MU-Fos-62/3a); first vein bearing a row of about 20 setae, second vein bearing about 17 setae, posterior fringes straight; clavus with six marginal and one discal setae. Hind wings ( Fig. 8) without any veins; membranous with some sparse microtrichia developed only around extreme tip. Legs covered with microtrichia; fore femora stout ( Fig. 4); hind femora slightly enlarged ( Fig. 4); tarsi 2-segmented. Abdominal tergites II–VII laterally with a row of posteromarginal setae that is less interrupted in the distal segments and finally closed to a continuous comb on tergite VIII ( Fig. 4). Abdominal sternites II–VII with a complete row of many posteromarginal setae (about 30 on III); discal setae lacking. Abdominal segments IX and X conically shaped, with strong setae; X dorsolaterally with a pair of large trichobothria ( Fig. 6).

Male MU-Fos-62/3b ( Figs 5, 8). Similar to females in colour and shape, however smaller and rather slim; legs yellowish brown (possibly due to reflections in the amber). Abdomen slender; segment I much longer than in females and conically extended from its base; distal abdominal segments conically tapering; trichobothria on X lacking; genitals not visible.

Measurements. Female MU-Fos-62/1 (in microns): Body, length 1166 (abdomen slightly contracted). Head, length 113; width 183. Eyes, length 76, width 44. Hind ocelli, diameter 13; distance between the hind ocelli 34. Ocellar setae 3 40. Postocular setae s1 62, s5 62, s6 25. Maxillary palps, length 76. Pronotum, length 167; width 248; anterior marginal setae 22–24, lateral marginal setae 19–22, posterior marginal setae 30–34, posteroangular setae 93, discal setae 10–12. Pterothorax, largest width 265. Mesothoraxic lateral setae about 110 (difficult to measure due to their bend); mesonotal median setae 16. Abdomen, length 693; largest width 340 (segment V). Antennae, length 355; length (width) of segment I 25 (25), II 47 (25), III 65 (26), IV 68 (11), V 43 (11), VI 31 (9), VII 25 (9), VIII 22 (8), IX 28 (6). Fore wings, length 680; largest width 107; width at level of the r-m-cross vein 85.

The specimens differ greatly in their body size. The female MU-Fos-63/1 is much larger, reaching a body length of 1836 (fully distended); measurements are longer, respectively.

Male: Body, length 870. Head, length 113; width 126. Eyes, length 70, width 32. Longest postocular setae 50. Pronotum, length 124; width 180; posteroangular setae 74. Abdomen, length 465; largest width 130 (segment III); segment I, length 93. Antennae, length 305.

Material studied: Syntypes: Four females, MU-Fos-62/1 ( Fig. 1), MU-Fos-62/2 ( Fig. 4), MU-Fos-62/3a ( Fig. 7), MU-Fos-63/1 ( Figs 2, 3, 6), one male MU-Fos-62/3b ( Figs 5, 8). All samples were purchased on eBay from two sellers (“the-past-experience”: www.ebay.com/usr/the-past-experience, and “amber_resin_fossils”: www.ebay.com/usr/amber_resin_fossils) by Maximilian, Madeline and Mark Pankowski and generously donated to the author. The origin of the amber is the north of Myanmar, as certified by the sellers. All five syntypes are deposited in the Senckenbergische Naturforschende Gesellschaft, Frankfurt am Main, Germany ( SMF T 19277– 19281). Specimens excluded from the syntypic series: 29 females in several amber pieces in collection Ulitzka.

Etymology. The species name ‘ pankowskiorum ’ is gratefully dedicated to the Pankowski family for their donations of the Burmite samples.

Comments. Females of M. pankowskiorum sp. n. have been commonly found in many different samples of Burmese amber, often in high numbers. This abundance possibly could indicate a swarming behaviour, as seen in some extant thrips known as thunder flies (cf. Ulitzka 2018). At present the collection of the author includes 34 females of this species, however, only one single male. This result coincides with the sex ratio found in many field populations of extant thrips ( Lewis 1973).