Triangulum thutai Jiang & Li, 2022

Xin, Yafei, Jiang, Tongyao, Yao, Zhiyuan & Li, Shuqiang, 2022, Twenty new spider species (Arachnida: Araneae) from Late Cretaceous Kachin amber (Myanmar), Zoological Systematics 47 (1), pp. 1-65 : 64

Triangulum thutai Jiang & Li , sp. nov. ( Figs 58–60 )

Holotype. Male (IZCAS-Ar42704Fo). Late Cretaceous amber from Hukawng Valley. No biotic syninclusions.

Etymology. The species name is a popular Burmese boy’s name and means “knowledge”; noun in apposition.

Diagnosis. The new species can be distinguished by the characters of the genus.

Description. Male. Total length 1.29; carapace 0.58 long, 0.34 wide, 0.54 high; opisthosoma 0.71 long, 0.46 wide. Left palp: - (0.22 + - + -), left leg I: - (0.52 + 0.12 + 0.42 + 0.46 + 0.28), leg II: (0.48 + 0.20 + 0.26 + 0.28 + 0.22), leg III: 1.06 (0.20 + 0.16 + 0.24 + 0.26 + 0.20), leg IV absent; right palp: absent, right leg I: 1.65 (0.56 + 0.11 + 0.42 + 0.36 + 0.20), leg II: 1.41 (0.40 + 0.15 + 0.32 + 0.30 + 0.24), leg III: 1.00 (0.32 + 0.08 + 0.20 + 0.22 + 0.18), leg IV: 1.34 (0.34 + 0.10 + 0.32 + 0.32 + 0.26). Eye sizes and interdistances: ALE 0.04, AME 0.80, PLE 0.04, PME 0.04; AME–AME 0.10, PME–PME 0.04. Habitus as in Figs 58C–E , 59A–D . Carapace ( Figs 58C–E ): carapace rather high but not cylindrical; sternum yellowish, round, with dense setae; eye region raised, clypeus projecting. AME largest, posterior row slightly recurved as seen from above, PME smallest. Opisthosoma ( Figs 59A–D ): Abdomen oval, covered with long setae. Legs unmodified, slender, fairly long with long bristles.

Palp ( Figs 58A–B , 60 ). Femur longer than patella, patella and tibia without apophyses; cymbium voluminous and round; embolus small and slender; tegulum large; median apophysis not visible; tegulum sclerotized.

Funding This study was supported by the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (2015CASEABRI005, Y4ZK111B01).

Acknowledgements The manuscript benefited greatly from comments by Yuri Marusik ( Magadan, Russia). Sarah Crews (San Francisco, USA) kindly checked the English of the final draft.

Figures

Figure 58. Triangulum thutai Jiang & Li, sp. nov., holotype male (IZCAS-Ar42704Fo). A–B. Left palp (A. Prolateral view, B. Retrolateral view); C–D. Ocular area (C. Dorsal view, D. Lateral view); E. Spinnerets, ventral view. Scale bars=0.05mm.

Figure 59. Triangulum thutai Jiang & Li, sp. nov., holotype male (IZCAS-Ar42704Fo). A–B. Habitus (A. Ventral view; B. Dorsal view); C–D. Habitus, lateral view. Scale bars=0.50mm.

Figure 60. Triangulum thutai Jiang & Li, sp. nov., holotype male (IZCAS-Ar42704Fo), left palp, retrolateral view. Scale bar = 0.05mm.