Criniverticillus Lin, Yao & Ren, 2018

Lin, Shan, Yao, Yunzhi & Ren, Dong, 2018, A new scale insect of the extinct family Weitschatidae (Insecta: Hemiptera: Coccomorpha) from mid-Cretaceous Burmese amber, Zootaxa 4407 (3), pp. 427-434 : 428-431

Genus Criniverticillus Lin, Yao & Ren gen. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:A5025B96-B712-418B-958C-FB3A91475B51

Type species. Criniverticillus longicumulus Lin, Yao & Ren sp. nov.

Diagnosis (macropterous male). Body large (ca. 2 mm long, Fig. 1 ); antenna long (ca. 2.1–2.4 mm, Fig. 2F ), most antennal setae forming distinct whorls, antennal apical segment with curved bristles ( Fig. 2G ); hamulohaltere leaf-shaped; basisternum without a median ridge ( Fig. 2B ); abdominal tergites well developed and sclerotized, first three tergites each with distinct median ridge ( Fig. 2A ); abdominal tergites VI and VII each with a transverse row of 7–9 tubular ducts ( Fig. 2A ) extruding wax filaments; a pair of short tubercular projections present on apex of abdominal segment VIII ( Fig. 2 C ).

Etymology. The generic name Criniverticillus comes from combination of the prefix ‘ crini- ’ (from the Latin crinis meaning ‘hair’) with the masculine Latin noun ‘ verticillus ’ (meaning ‘whorl’), referring to most of the setae on the antenna forming whorls around the segments.

Remarks. Koteja (2008) considered that the following extinct genera were xylococcid-like taxa: Arnoldus Koteja ; Grohnus Koteja ; Lithuanicoccus Koteja ; Serafinus Koteja , and Weitschatus Koteja , and classified them in five families: Arnoldidae , Grohnidae , Lithuanicoccidae , Serafinidae and Weitschatidae respectively. After comparing key structures like antennal capitate setae; pterostigma on forewing; radial sector on forewing; hamulohaltere; basisternal median ridge; small caudal extension on tergite VIII; tarsal digitule; penial sheath; anterior margin of scutellum, and membranous lateral areas of scutellum, Vea & Grimaldi (2015) questioned this classification and considered that further analyses of relationships within the xylococcid-like taxa were needed. According to our observations, based on the body and wing shapes, antennae without specialised setae, subtriangular scutellum and waxy tail tufts of our adult male Criniverticillus, we think these genera are very similar to each other, and are inclined to support the latter authors’ point of view.

Among the Xylococcid-like genera, records from the Cretaceous only comprise Xiphos Vea & Grimaldi (family placement uncertain) from the Early Cretaceous Lebanese amber and Pseudoweitschatus Vea & Grimaldi from the mid-Cretaceous Burmese amber; all other fossil records are from the Eocene Baltic amber. However, the morphological characters of Xiphos are very different from the other genera, such as: body small (ca. 1.45 mm long total); scutum with an oval membranous area; forewings each without anterior flexing patch; claw digitule absent, and penial sheath extremely elongate. The Xylococcid-like taxa therefore only have one important record ( Pseudoweitschatus ) from the Cretaceous. The new species described in this paper adds to the record of the Weitschatidae in the mid-Cretaceous and provides a significant new addition to the understanding the past diversity of scale insects.

The new genus described herein is assigned to the family Weitschatidae based on the presence of the following features (contrasting conditions in the other fossil taxa/families are given in brackets): antennae without capitate setae (capitate setae present in Arnoldus ( Arnoldidae )); radial sector of forewing absent (present in Xylococcus ( Xylococcidae )); tarsal digitules undifferentiated (clavate in Arnoldus and Xiphos ); membranous lateral areas of scutellum absent (present in Grohnus (Grohnidae) and Xiphos ) and cubital ridge extending beyond middle of wing (cubital ridge very short, reaching posterior wing margin at 1/4 its length in Serafinus ( Serafinidae )). In particular, the shape of the pterostigma in Criniverticillus is very similar to that of Weitschatus and Pseudoweitschatus (Weitschatidae) (absent in other Xylococcid-like taxa).

Criniverticillus differs from the other two genera in Weitschatidae by the following combination of characters (contrasting conditions in the other taxa are given in brackets): antenna significantly longer, 2.10–2.40 mm in Criniverticillus (1.30–1.33 mm in Pseudoweitschatus ); most setae on antenna forming distinct whorls (without whorls in Weitschatus ); antennal apical segment with the short ‘curved bristles’ of Vea & Grimaldi (2015) (absent in Weitschatus ); hamulohaltere leaf-shaped (bilobed in Weitschatus ); first three abdominal tergites with distinct median ridge (median ridge absent in Weitschatus and Pseudoweitschatus ); a single row of tubular ducts present on each of abdominal tergites VI and VII (2–4 rows of pores in Weitschatus ), and the presence of a pair of short tubercular projections on the apex of abdominal segment VIII (absent in Pseudoweitschatus ).

Figures

FIGURE 1. Holotype of Criniverticillus longicumulus Lin, Yao & Ren gen. et sp. nov. CNU-COC-MA2018001. Photomicrographs of (A) dorsal and (B) ventral views; line drawings of (C) dorsal and(D) ventral views.Scale bars = 1.0 mm. afp: anterior flexing patch; dse: dorsal simple eye; en: endophallus; mrt: median ridge on tergite; pfp: posterior flexing patch; sscr: sensorium on subcostal ridge; tp: tubercular projection.

FIGURE 2. Detailed photographs of Criniverticillus longicumulus Lin, Yao & Ren gen. et sp. nov. holotype, CNU-COC- MA2018001. (A) dorsal and (B) ventral views of body; (C) left tubercular projection on apex of abdomen in (B); (D) ventral view of right mid- and hind legs; (E) claw, tarsus and part of tibia (note bifurcate setae and spine-likeclaw digitules) in (D); (F) ventral view of antennae; (G) apical antennal segment in (F); (H) lateral view of apex of antenna (note basiconic sensilla); (I) dorsal view offorewing; (J)dorsal view of hamulohalteres.Scale bars for A, B,D, F, I = 0.4 mm; C = 0.05 mm;E, G, H, J = 0.1 mm.