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.