Retrooecobius lwini 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 : 3

Retrooecobius lwini Jiang & Li , sp. nov. ( Figs 1–3 )

Holotype. Male (IZCAS-Ar42683Fo). Late Cretaceous amber from Hukawng Valley. Syninclusion includes one neuropteran.

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

Diagnosis. Retrooecobius lwini Jiang & Li , sp. nov. can be distinguished from R. chomskyi Wunderlich, 2015 (figs 313–321, photos 149–153), the only species of the genus described based on male specimen before, by the clypeus. R. chomskyi has a clypeal apophysis, while the new species does not have. In addition, the palp of R. chomskyi was obscured.

Description. Male. Total length 3.09; carapace 1.33 long, 1.25 wide; opisthosoma 1.76 long, 0.88 wide. Left palp: - (0.29 + - + -), left leg I: - (1.07 + - + - + 1.19 + 0.64), leg II: - (- + - + - + 1.17 + 0.71), leg III: 4.30 (0.99 + 0.40 + 0.78 + 1.18 + 0.95), leg IV: 4.87 (1.15 + 0.46 + 1.01 + 1.37 + 0.88); right palp: - (0.67 + - + -), right leg I: 4.44 (1.25 + 0.45 + 0.90 + 1.12 + 0.72), leg II: 4.39 (1.34 + 0.41 + 0.91 + 1.20 +0.53), leg III: - (1.56 + - + - + 1.31 + 0.75), leg IV: 5.28 (1.68 + 0.41 + 0.97 + 1.24 + 0.98). Eye sizes and interdistances: ALE 0.09, AME 0.07, PLE 0.07, PME 0.08; AME–AME 0.08, AME– ALE 0.04, PME–PLE 0.03, PME–PME 0.08. Habitus as in Figs 2A–B . Carapace has an obvious fovea, longer than wide, brown, covered with dark brown setae. Sternum brown, with dense brown setae. Labium not visible. Legs with long setae, approximate to width of leg segment. Opisthosoma elongate, black-brown. Anterior and posterior spinnerets ( Fig. 2D ) are approximately the same length.

Palp ( Figs 1A–D , 3 ). Ratio of femur length to cymbial length 2.71; median apophysis triangular, sclerotized.

Figures

Figure 1. Retrooecobius lwini Jiang & Li, sp. nov., holotype male (IZCAS-Ar42683Fo). A. Left palp, retrolateral view; B–C. Right palp (B. Retrolateral view; C. Ventral view); D. Left palp, ventral view. Scale bars=0.10mm.

Figure 2. Retrooecobius lwini Jiang & Li, sp. nov., holotype male (IZCAS-Ar42683Fo). A–B. Habitus (A. Dorsal view; B. Ventral view); C. Ocular area, dorsal view; D. Spinnerets, ventral view. Scale bars: A–B=0.50mm; C–D=0.10mm.

Figure 3. Retrooecobius lwini Jiang & Li, sp. nov., holotype male (IZCAS-Ar42683Fo), left palp, retrolateral view. Scale bar = 0.10mm.