Pilosarachne, Jiang & Li, 2020

Jiang, Tongyao, Xin, Yafei, Yao, Zhiyuan & Li, Shuqiang, 2020, Two new spider families from Late Cretaceous Kachin amber (Arachnida: Araneae), Zoological Systematics 45 (4), pp. 266-280 : 268-272

publication ID	https://doi.org/ 10.11865/zs.202033
publication LSID	lsid:zoobank.org:pub:00441A2B-31CF-400B-B2AA-E7BEA6775439
persistent identifier	https://treatment.plazi.org/id/FE7987DA-FFD3-FFFA-BCFE-F89317A5FAB3
treatment provided by	Diego
scientific name	Pilosarachne
status

Treatment

Pilosarachne ju Jiang & Li, sp. nov. ( Figs 1–3 View Figure 1 View Figure 2 View Figure 3 )

Holotype ♂ (IZCAS-Ar41629Fo), Late Cretaceous amber from Myanmar , Kachin State, Hukawng Valley . No biotic syninclusions.

Etymology. The specific name is derived from the Chinese pinyin word for “saw” (jù), referring to the saw-like serrate structure near embolus, and is a noun in apposition.

Diagnosis. The new species can be distinguished by the characters of the family, as given above.

Description. Male (holotype). Body length 5.12, carapace 2.50 long, 2.20 wide, abdomen 2.62 long, 1.25 wide. Eyes: AME 0.20, ALE 0.13, PME 0.15, PLE 0.14, AME-AME 0.39, AME-ALE 0.31, PME-PME 0.44, PME-PLE 0.26, AME- PME 0.19, ALE-PLE 0.03, CH AME 0.17, CH ALE 0.21. Spination: palp: 1320, 1210, 1314; legs: femur I 424, II 324, III 2(3)22(3), IV 2(3)33; patella I 2122, II 2013, III 2100, IV 21(2)20; tibia I 3223, II 1022 (incomplete), III 2123, IV 2226; metatarsus I 2(4)332(3), II 3(4)43(4)3(4), III 2234 (incomplete), IV 3222; tarsus without spines. Measurements of palp and legs: left side: palp 3.71 (1.75, 0.31, 0.88, 0.77), leg I 12.71 (3.38, 0.98, 2.65, 4.02, 1.68), leg II 8.98 (2.63, 0.66, 1.71, 2.84, 1.14), leg III - (1.6, -, -, 1.36, -), leg IV - (2.28, 0.49, 1.71, -, -); right side: palp - (-, 0.40, 0.93, 0.80), leg I - (3.56, 1.03, 2.78, -, -), leg II - (2.68, 0.65, -, -, 1.15), leg III 4.9 (1.73, 0.30, 0.88, 1.40, 0.59), leg IV 7.79 (2.30, 0.45, 1.56, 2.50, 0.98).

Carapace piriform, covered by dense feathery scales; pars cephalica not elevated; fovea distinct, longitudinal ( Fig. 2E View Figure 2 ). Eight eyes; ALE and PLE contiguous, arising from a common tubercle; anterior eye row slightly recurved in anterior view, posterior eye row recurved in dorsal view ( Fig. 2E View Figure 2 ). Clypeus short, clypeus height at AME shorter than diameter of AME. Cheliceral teeth covered by setae at promargin and thus unknown; fangs long; chilum absent ( Fig. 2F View Figure 2 ). Endite not converging, widened distally, probably longer than width; serrula in a single row ( Fig. 2F View Figure 2 ); labium not observable; sternum extending between coxae IV. Legs annulated, leg formula 1243, covered by dense feathery scales; tactile hairs plumose ( Fig. 2C View Figure 2 ); spines numerous ( Fig. 2A View Figure 2 ; see above), but absent from all tarsi; spines at apex of metatarsi forming a ring (or “garland”); metatarsal preening combs absent; vestigial calamistrum in male absent (in contrast to some extinct families, e.g., † Burmadictynidae Wunderlich, 2017 , † Frateruloboridae Wunderlich, 2018 , which have a distinct vestigial calamistrum even in adult males); femoral trichobothria absent; ITC present, slightly smaller than STC ( Fig. 2B View Figure 2 ); STC teeth uniseriate, four or five ( Fig. 2C View Figure 2 ); serrate accessory claw setae present. Abdomen elongated, length more than two times width, unsclerotized, covered by feathery scales; pedical, booklungs and spiracle not well observable; three pairs of spinnerets, a small vestigial cribellar region is most likely present but was not able to be observed explicitly ( Fig. 2D View Figure 2 ).

Male palp ( Figs 3A–D View Figure 3 ). Femur shorter than length of carapace, without apophysis ( Fig. 3D View Figure 3 ). Tibia without apophysis, but apically with curved tapering spines on retrolateral and dorsal sides ( Figs 3A, C–D View Figure 3 ). Cymbium spoon-shaped, with two prolateral spines ( Figs 3B–D View Figure 3 ). Tegulum discoid. A serrate structure is present at prolateral margin of tegulum, near base of embolus, bearing more than 10 teeth ( Figs 3B, D View Figure 3 ). A dubious median apophysis is present, arising near center of tegulum, wrinkled and blunt, covering base of conductor in ventral view. Conductor most likely membranous, arising from tegulum at 1 o’clock, curved, its end directed proximally ( Figs 3A–B, D View Figure 3 ). Embolus arising from tegulum at 5 o’clock position, accompanied by membranous pars pendula nearly its whole length, running counterclockwise, embolic tip ending near apex of cymbium ( Figs 3B, D View Figure 3 ).