Chiridurothrips dominicus, Ulitzka, 2019

Ulitzka, Manfred R., 2019, A new species of Chiridurothrips Okajima from Miocene amber of the Dominican Republic (Thysanoptera: Phlaeothripidae), Zootaxa 4686 (1), pp. 140-144 : 141

Chiridurothrips dominicus sp. n. ( Figs 1–4 )

Female macroptera. Body slightly contracted; fore legs angled, mid and hind legs extended; wings fully spread. Colour ( Figs 1, 2 ) dark brown including antennae and legs; major body setae and wing fringes dark; wing membrane shaded brownish, extreme tip of forewing and clavus somewhat darker.

Head retracted basally under pronotum ( Fig. 2 ); longer than wide, projecting in front of the compound eyes, with cheeks slightly rounded behind eyes and converging straight towards base; dorsally with reticulate sculpture. Ocelli large; posterior pair close to compound eyes. One pair of short ocellar setae visible just behind posterior ocelli. Postocular setae broken off, their points of insertion visible far behind the eyes. Antennae ( Fig. 3 ) 8-segmented; segment I barrel-shaped; segment II basally with a cone-shaped pedicle, apically polygonal and bluntly prolonged at the inner edge, sensilla situated between base and middle; III–VII basally with a slender pedicel, then inverse conically shaped and tapering distally from level of sense cones; VIII spindle-shaped, at base much narrower than segment VIII distally; III and V each with two sense cones (1+1), IV with two or three sense cones (1+1 or 1+2) – difficult to assess, VI with one sense cone (1+0), VII with one sense cone (0+1). Mouth cone short, rounded.

Prothorax not clearly assessable, deformed ( Fig. 2 ); pronotum small, laterally eroded; without prominent setae. Mesothorax and metathorax deformed by lateral distortion; both ventrolaterally with a pair of long fine, hair-like setae bent inwards to the front. Fore wings ( Fig. 1 ) parallel-sided; with 6–7 duplicated cilia; subbasal wing setae as well as subbasal wing vein lacking. Fore legs ( Fig. 4 ) with femora slightly enlarged, each with a long hair-like seta; fore tarsi with a large tarsal tooth and a hamus consisting of three discrete teeth („ dentate pseudungius “ c.f. Bhatti 1998: 258). Mid and hind tibiae each dorsally and laterally with a fine long seta, their ventral tips each with one spur-like apical seta; mid and hind tarsi two-segmented, each with a recurved hamus.

Pelta not assessable. Tergites without sigmoid wing retaining setae; lateral setae short, pointed. Sternites with short discal setae (only some visible). Segment IX tapering dome-shaped, with setae pointed, s1 short, s2 long, but not protruding tube. X (tube) long and slender, concavely extended at base and sharply constricted distally; anal setae weak but longer than tube.

Measurements. Holotype in microns: Body length 1188. Head, length 202; width 124. Eyes, length 60; width 31. Ocelli diameter 16; distance between hind ocelli about 40. Prothorax, length about 202; width not measurable (deformed). Pterothorax, not measurable (deformed); ventrolateral hair-like setae on mesothorax about 155, on metathorax about 190. Abdomen, length 542; largest width 217 (segments V); segment X (tube), length 90; basal width 47. Setae on tergite IX, s1 34, s2 74; longest anal setae 155. Antennae, length 296; length (largest width) of segment I 28 (28), II 31 (37), III 40 (31), IV 47 (28), V 37 (22), VI 39 (19), VII 37 (12), VIII 37 (6). Fore wings, length 706; width in the middle 65.

Specimen studied. Holotype female, inclusion in Dominican Miocene amber from the La Burca mine in the North of the Dominican Republic. Collection Ulitzka No. MU-Fos-83/1.

Syninclusions: One mite and parts of a fly (both not identified); small particles of plant detritus; numerous fungal spores attached to the thrips at its body, legs, and particularly at the base of the wings ( Fig. 2 ).

Etymology. The species epithet dominicus refers to the country in which the amber deposit is located, the Dominican Republic.

Comparisons. The combination of the following character states makes the new species clearly associable with Chiridurothrips : (1) head elongate and projecting in front of the eyes, (2) tube long, (3) antennal segment II asymmetrically prolonged at inner apex, (4) fore wing without subbasal wing vein and subbasal wing setae, (5) fore tarsi with a large tarsal tooth and a hamus consisting of three discrete teeth. Chiridurothrips dominicus sp. n. differs from the type species C. hisakoae first of all in the distinctly smaller body size. Furthermore, setae s2 on tergite IX are much longer than s 1 in the new species, whereas their length is subequal in C. hisakoae . In C. dominicus sp. n. the anal setae are much longer than the tube, in C. hisakoae shorter. Regarding the fore wings, the number of duplicated cilia is much higher in C. hisakoae (30) than in the new species (6–7). Due to these features, C. dominicus sp. n. is clearly distinguishable from C. hisakoae . Moreover, according to zur Strassen (1973) fossils found in amber are generally not attributable to extant species. Species vary in the course of time and therefore each of them has only a limited period of existence.

Figures

FIGURES 1–4. Chiridurothrips dominicus sp. n. holotype female. (1) dorsal view; (2) head and thorax, indicated red: thoracic ventrolateral setae, black: clusters of fungal spores (others are visible at the legs and the wing base); (3) right antenna; (4) left fore leg, indicated black: femoral hair-like seta, red: tarsal tooth, white: dentate pseudungius (hamus consisting of three discrete teeth).