Merothrips mizoramensis, Johnson & Mound & Varatharajan, 2021

Johnson, Th., Mound, L. A. & Varatharajan, R., 2021, A new species of Merothrips from the Dampa Tiger Reserve, Mizoram, India (Thysanoptera, Terebrantia), Zootaxa 4926 (4), pp. 597-600 : 598

Merothrips mizoramensis sp. n.

( Figs 1–7 )

Female macroptera. Body exceptionally long and slender ( Fig. 1 ), light brown, head progressively darker towards base of antennae; legs and antennae uniformly yellow; fore wings grey with longitudinal vein darker. Antennae 8-segmented, segments III and IV each with a transverse oval sensorium, surface microtrichia absent; III large, almost quadrate, IV smaller than III, V‒VII small ( Fig. 3 ). Head with compound eyes well developed, ocelli not developed; pre-ocular vertex with one pair of setae arising in transverse line with campaniform sensilla ( Fig. 2 ); postocular setae not developed. Prothorax elongate; with narrow median sclerite delimited by long notopleural sutures; this pronotal sclerite bears medially several longitudinal sculpture lines, but with anterior, lateral and posterior areas finely granulate; anterior margin with one pair of minute setae, and lateral margins on anterior half with two pairs of minute setae; two pairs of posteromarginal setae, of which the lateral pair is minute; notopleural suture incomplete posteriorly with the two posteroangular setae arising lateral to this suture on the epimeral sclerite, one seta long and one very short. Fore coxae long and swollen, with two pairs of long setae, one ventrally and one laterally ( Fig. 4 ). Fore tarsi apparently with pre-apical claw. Meso and metathorax greatly elongate. Mesonotum medially with weak longitudinal lines of sculpture; mesosternum with bold elongate reticulation. Metanotum with longitudinal reticulation on anterior half and one pair of setae medially, posterior half without sculpture but with one pair of minute setae; metascutellum without sculpture except for a few lines near posterior margin. Fore wing with a single longitudinal vein bearing 7 (or 9) setae ( Fig. 6 ), and no indication of a veinal fork or second vein ( Fig. 7 ); posterior margin with the usual two series of cilia, all of them strongly wavy; clavus without veinal setae. Tergites and sternites each with longitudinal lines of sculpture medially; tergite VIII spiracles scarcely 5 microns in diameter; tergite IX with two pairs of long setae; tergite X with trichobothria represented by pair of very small campaniform sensilla with no axial seta. Sternites II‒VII with many strong longitudinal sculpture lines; sternite VII with 2 pairs of minute discal setae, with 3 pairs of marginal setae and 1 or 2 pairs of minute setae on weakly sclerotised posteromarginal lobes ( Fig. 5 ).

Measurements (holotype female in microns). Body length 1120. Head, length 85; width 54. Pronotum, length 80; epimeral setae 40. Coxa lateral setae 30. Fore wing length 600. Tergite IX median and lateral setae lengths 70. Antennal segments I‒VIII length (width), 18 (18), 20 (16), 24 (17), 23 (15), 19 (13), 19 (13), 17 (13), 29 (12), respectively.

Specimen examined. Holotype female macroptera, INDIA, Mizoram, Dampa Tiger Reserve (23 o 36’ N and 92 o 20’ E), from dried twigs, 31.x.2014 (Th. Johnson), deposited in the Indian National Bureau of Insect Resources , Bengaluru.

Comments. The single available specimen is slightly distorted, with the compound eyes apparently slightly compressed laterally ( Fig. 2 ), and the abdominal segments similarly compressed laterally. Despite the fore wings being fully developed ( Figs 6, 7 ) there is no indication of any ocelli on the head, and on tergite X the trichobothria are absent despite these structures generally being present in macropterous females of Merothrips species ( Mound & O’Neill 1974). This new species is unusually long and slender, with the pterothorax particularly long. It differs from other members of this genus in having many sclerites bearing longitudinal lines of sculpture, including the pronotum, tergites and sternites, in having the fore wing with a single longitudinal vein ( Fig. 7 ), and in having an elongate prothoracic notum that is delimited by longitudinal notopleural sutures ( Fig. 4 ). The structure of the elongate meso and metathorax is particularly difficult to interpret due to their weak sclerotisation, but both of them are unusually elongate.

Figures

FIGURES 1‒7. Merothrips mizoramensis: (1) female; (2) head; (3) antennae; (4) prothorax; (5) sternite VII; (6) fore wing apex; (7) fore wing base.