Lineaburmops beigeli, WUNDERLICH, 2015

Guo, Xiangbo, Selden, Paul A. & Ren, Dong, 2022, New specimens from Mid-Cretaceous Myanmar amber illuminate the phylogenetic placement of Lagonomegopidae (Arachnida: Araneae), Zoological Journal of the Linnean Society 195, pp. 399-416 : 408

LINEABURMOPS BEIGELI WUNDERLICH, 2015

( FIGS 4 , 5 )

Wu n d e r l i c h (2 0 1 5): 2 5 5 –2 5 6, f i g s 2 3 6, 2 3 7, photos 104, 105.

Material: Two adult males, specimen nos CNU-ARA-MA2020003 and CNU-ARA-MA2020004.

Locality and horizon: Hukawng Valley, Kachin State, northern Myanmar; lowermost Cenomanian, Mid-Cretaceous.

Taphonomic features: CNU-ARA-MA 2020003: the pedicel and abdomen are somewhat broken; metatarsus, tarsus of left leg I, II and patella of left leg IV are missing; there are a few bubbles and impurities around the spider. A thrips near the tibia of left leg III is present as a syninclusion. CNU-ARA-MA2020004: the tarsus of left leg IV is incomplete, tarsal claws are missing; and there are many impurities and cracks around the spider.

Description: Body length 2.98–3.08, dark-coloured, with a subtriangular white patch on clypeus, a pair of reniform white patches on the thoracic region and a pair of white longitudinal stripes on the abdomen dorsally ( Figs 4A, B , 5F ). Carapace length 1.57–1.59, width 0.96–0.99 at widest point, covered with short, dense, feathery setae pressed flat against the cuticle. Cephalic region of carapace slightly raised, with a pair of anterolateral protrusions next to the inner side of PME. Neck present between cephalic and thoracic regions, slightly narrower than cephalic region. Fovea absent. Eight eyes present; PME enormous, 0.17 in diameter, situated on anterolateral corner of carapace; PLE small, placed at the mediolateral margin of cephalic region, separated 0.25 from the PME centre; AME and ALE contiguous, situated between the PME and the clypeal margin. Chelicera length 0.58 and width 0.29 at base, cheliceral insertion distinctly separated from mouthparts, stridulatory files absent. Fang length 0.19. Chelicera with about eight peg teeth on promargin ( Fig. 4C ); retromargin not visible. Labium subtriangular, slightly longer than wide, not fused to sternum. Endites elongated, converging but not meeting in midline; serrula as a single row of teeth. Sternum covered with setae, convex and without tubercles.

Palpal podomere lengths: fe 0.51, pa 0.18, ti 0.27, ta 0.67. Palp hairy, feathery setae at least present on tarsus. Tibia with three dorsal trichobothria in a single row ( Fig. 5A ). Cymbium elongate, finger-like distally ( Fig. 5A ). Detailed structures of male palp, such as embolus and conductor, not recognizable.

Legs long but no legs enlarged; metatarsus distinctly much longer than tarsus in anterior legs; metatarsus slightly longer than tarsus in posterior legs. Leg formula I> II> IV> III: leg I cx 0.31, tr 0.07, fe 1.47–1.58, pa 0.34, ti 1.44–1.60, mt 1.10–1.16, ta 0.66–0.75; leg II cx 0.37, tr 0.07, fe 1.49–1.53, pa 0.31–0.37, ti 1.43–1.45, mt 1.08–1.11, ta 0.66–0.71; leg III cx 0.24–0.28, tr 0.06, fe 1.14–1.17, pa 0.30–0.32, ti 1.02–1.14, mt 0.67–0.69, ta 0.50–0.57; leg IV cx 0.29– 0.31, tr 0.08, fe 1.46–1.51, pa 0.32–0.35, ti 1.28–1.42, mt 0.83–0.86, ta 0.64–0.67. Metatarsus and tarsus without scopulae. Distal preening comb composed of six to eight short macrosetae, present on metatarsus of posterior legs ventrally ( Fig. 5C ). Feathery setae at least present on femur, patella, tibia and metatarsus ( Fig. 5B ). Tibiae at least with five, metatarsi at least with six, tarsi at least with nine trichobothria ( Fig. 5C, D ). Three tarsal claws, paired claws with five to eight teeth, median claw hook-like. Serrate accessory claw setae near the median claw present at least on left leg III ( Fig. 5E ).

Abdomen ovoid, length 1.27–1.34, width 0.65– 0.68, densely covered with short feathery setae. Spinnerets and anal tubercle encircled by a quadrate glabrous band. Four spinnerets visible. ALS with two segments, distal segment much smaller than basal segment; PLS about as large as ALS, details not visible ( Fig. 4E, F ).

Remarks: These two specimens can be assigned to Lineaburmops beigeli , the type species of genus Lineaburmops , by the following characters: the shape and placement of white patches on carapace and abdomen; the length of the podomeres.

Figures

Figure 4. Lineaburmops beigeli; CNU-ARA-MA2020003: A, habitus, dorsal view; B, schematic drawing of dorsal habitus; C, habitus, ventral view, showing peg teeth (magnified at the top); D, schematic drawing of ventral habitus; E, distal part of abdomen, ventral view, showing spinnerets and anal tubercle; F, schematic drawing of distal ventral abdomen. Scale bars represent 0.5 mm (A, B, C, D) and 0.1 mm (E, F).

Figure 5. Lineaburmops beigeli; CNU-ARA-MA2020003: A, tibia and male palp of right pedipalp, dorsal view, showing trichobothria (asterisks); B, distal femur of left leg III, lateral view, showing feathery setae; C, metatarsus of right leg IV, lateral view, showing trichobothria (asterisks) and preening comb (arrow); D, tarsus of left leg III, lateral view, showing trichobothria (asterisks); E, distal tarsus of left leg III, lateral view, showing claws and serrate accessory claw setae (arrow). CNU-ARA-MA2020004: F, overall habitus, dorsal view. Scale bars represent 0.5 mm (F), 0.1 mm (A, B, C, D) and 0.05 mm (E).