Angustitermes Jiang, Z.Zhao & Ren, 2024

Jiang, Yurong, Deng, Xinru, Shih, Chungkun, Zhao, Yunyun, Ren, Dong & Zhao, Zhipeng, 2024, Primitive new termites (Blattodea, Termitoidae) in Cretaceous amber from Myanmar, ZooKeys 1197, pp. 115-126 : 115

Genus Angustitermes Jiang, Z.Zhao & Ren gen. nov.

Type species.

Angustitermes reflexus Jiang, Z. Zhao & Ren, gen. et sp. nov. (Figs 1 - 3 ).

Etymology.

Angusti - is a Latin adjective, reflecting the fact that the medial field of this genus is narrow, and termes is the usual noun for the generic name in Termitoidae. The gender is masculine.

Diagnosis.

Imago: ocelli oval; fontanelle absent; Y-suture absent; mandibles not exceeding labrum; antenna moniliform with 22 articles; compound eyes lying in middle position on head; pronotum saddle-shaped. Wings heavily reticulated, with “cross-veins” present. Forewing: scale large, overlapping hind wing base, humeral suture convex; all major veins origin in scale; veins Sc, R1, R2, Rs, and M more pigmented than CuA; Sc simple; Rs with about three main branches, terminating on costal margin anterior to wing apex; radial field narrow, parallel to costal margin; M closer to Rs than CuA, lying more or less parallel to Rs as a simple vein for the greater part of its length, first branching in apical 1/5 of wing length, medial field narrow, encompassing wing apex; CuA branched, lying above the mid-longitudinal line of wing; CuP (claval suture) arched, meeting basal suture before posterior margin. Hind wing: basal suture not visible, large anal lobe present. Legs: tibial spines of all legs present; tibial spur formula 3-4-4; tarsi pentamerous; arolium present. Abdomen: cerci short, trimerous; abdominal styli absent.

Remarks.

Based on the sclerotized vein M, presence of the anal lobe, saddle-shaped pronotum, pentamerous tarsi, etc., Angustitermes gen. nov. is considered to belong to the Mastotermitidae and is assigned to the subfamily Mastotermitinae because of the ocelli (Fig. 1C ). Besides the new genus and Mastotermes , there are two other genera in Mastotermitinae : Garmitermes Engel, Grimaldi & Krishna, 2007 and Magnifitermes Jouault, Engel & Nel, 2022. Termites in both Angustitermes gen. nov. and Garmitermes have a rounded head, but unlike Angustitermes gen. nov., Garmitermes has 26 antennal articles, the arolium is greatly vestigial or absent, and the tibial spur formula of Garmitermes is 3-5-4 ( Engel et al. 2007). Both Angustitermes gen. nov. and Magnifitermes have arolium, and their tibial spur formula is the same. However, the shape of the head of Magnifitermes is relatively long and with about 28 antennal articles ( Jouault et al. 2022). Although in different subfamilies, Angustitermes gen. nov. and Anisotermes share many similarities, such as the rounded head and the tibial spur formula. However, the M vein of Anisotermes is located halfway between Rs and CuA, and the first inferior branch of the M vein on the hind wings gradually fades away, ultimately terminating in the center of the hind wings of Anisotermes ( Zhao et al. 2019; Jouault et al. 2022).

The major feature of Angustitermes gen. nov. is that the M vein is a simple vein for the greater part of its length, first branch branching in the apical 1/5 of wing length, and the medial field is narrow (Fig. 2B ). The simple M and narrow medial field of Angustitermes gen. nov. is similar to Blattotermes Riek, 1952. However, Angustitermes gen. nov. has sparser veins than Blattotermes ; the branches of R and secondary branches of CuA are fewer, and tertiary branch is absent; its forewings are much shorter, so that the difference in wing lengths between these two genera is more than 10 mm. Besides, the specimen of the new Angustitermes species is from the upper Cretaceous while the three Blattotermes species are from the Cenozoic: Blattotermes neoxenus Riek, 1952 and Blattotermes wheeleri (Collins, 1925) are from Eocene, and Blattotermes massiliensis Nel, 1986 is from Oligocene ( Collins 1925; Riek 1952; Nel 1986; Thorne et al. 2000; Krishna et al. 2013b).

Figures

Figure 1. Photographs and drawing of Angustitermes reflexus gen. et sp. nov., holotype specimen CNU-TER-BU- 2017005 (female imago) A habitus (dorsal view) B drawing of habitus (dorsal view) C head in dorsal view D head in ventral view E cerci in dorsal view. Scale bars: 4.0 mm (A, B); 1.0 mm (C); 0.5 mm (D); 0.2 mm (E).

Figure 2. Photograph and drawing of Angustitermes reflexus gen. et sp. nov., holotype specimen CNU-TER-BU- 2017005 (female imago) A habitus (ventral view) B partial reconstruction with wings unfolded. Scale bars: 4.0 mm (A); 4.0 mm (B).

Figure 3. Drawings of Angustitermes reflexus gen. et sp. nov., holotype specimen CNU-TER-BU- 2017005 (female imago) A drawing of habitus (ventral view) B-D drawings of femur, tibia, tarsi, arolium and claw of left hind leg, mid-leg and foreleg, respectively E drawing of head in dorsal view. Scale bars: 4.0 mm (A); 0.5 mm (B, C, D); 2.0 mm in (E).