Myrmarachne tintinnabulum Yamasaki, 2018

Yamasaki, Takeshi, Hashimoto, Yoshiaki, Endo, Tomoji, Hyodo, Fujio, Itioka, Takao & Meleng, Paulus, 2018, New species of the ant-mimicking genus Myrmarachne MacLeay, 1839 (Araneae: Salticidae) from Sarawak, Borneo, Zootaxa 4521 (3), pp. 335-356 : 348-349

Myrmarachne tintinnabulum Yamasaki sp. nov.

( Figs 50–64 )

Type material. Holotype: male ( FRCS; LMy20140331_Ad1), Sungai Liku , Lambir Hills National Park, Sarawak, Borneo, 31.III.2014, Y. Hashimoto & T. Endo leg. Paratypes: 1 female ( FRCS; LMy20140331_Ad2), same data as

holotype; 1 female ( MHNAH; LMy20140330_ TY30 ), same locality as in holotype, 30.III.2014, T. Yamasaki leg.; 1 female ( MHNAH; LMy20140328_ TY15 ), same locality as in holotype, 28.III.2014, T. Yamasaki leg.

Etymology. The specific name, a Latin noun in apposition, meaning a bell, referring to the bell-shaped outer margin of the pair of copulatory atria.

Diagnosis. Slender, blackish species, with long pedicel; pedicel longer than ALE–PLE but shorter than carapace. M. tintinnabulum sp. nov. is very similar to M. cornuta, but distinguishable from the latter by shape of RTA flange in males, and by the absence of median structure of epigyne in females.

Male ( Figs 50–53 ). Carapace laterally constricted behind PLE by slit-like furrow; thoracic part lower than PLE. Cheliceral paturon long, with seven prolateral and nine retrolateral teeth on fang furrow; first apical prolateral tooth truncated. Fang weakly sinuous; ventral surface undulate, without tooth-like apophysis. Pedicel longer than ALE–PLE, but shorter than carapace; anterior dorsal part shorter than posterior part. Abdomen slender pearshaped, dorsally with narrow scutum covering entire median area.

Male palp ( Figs 54–56 ). Cymbium oval. Embolus coils not wider than cymbium. Tegulum oval; spermophore curving in anterior part of tegulum, running along posterior margin of tegulum. RTA slender, strongly curved. Acutely pointed flange developed venter to RTA.

Leg macrosetae. Femur I md 1, pd 1; patella I pv 0, rv 1; tibia I pv 4, rv 4; metatarsus I pv 2, rv 2; femur II pd 1; tibia II pv 2, rv 2; metatarsus II pv 2, rv 2; femur III md 1, pd 2; femur IV pd 1, md 1.

Coloration and setation ( Figs 50–52 ). Carapace dark brown, covered with white setae, especially margin of carapace fringed with white setae; cephalic part darker than thoracic part; lateral surface of constricted area densely covered with white setae. Chelicera brown, covered with setae, some white, some black; outer surface covered with long white setae. Endite and labium dark brown, tinged with black. Sternum dark brown. Abdomen gray, covered with fine setae; dorsal scutum dark brown; anterior dorsum covered with white setae; constricted area dorsally bearing pair of white setal tufts.

Female ( Figs 57–60 ). Carapace constricted dorsally and laterally behind PLE; with carapace in lateral view, thoracic outline convex dorsally, thoracic top lower than upper margin of PLE. Chelicera with six prolateral and nine retrolateral teeth on fang furrow. Pedicel almost same as in male. Abdomen slender, with scutum as in male.

Epigyne ( Figs 61–64 ). Pair of copulatory atria surrounded by bell-shaped margins. Sclerotized copulatory ducts beginning from middle parts of inner margins of copulatory atria, extending to spermathecae with complex twists. Spermathecae small round. Pocket absent.

Leg macrosetae. Patella I pv 0, rv 1; tibia I pv 4, rv 4; metatarsus I pv 2, rv 2; tibia II pv 3, rv 3; metatarsus II pv 2, rv 2; legs III and IV without macrosetae.

Coloration and setation. Almost same as in male. Live female appearance shown in Figure 57 .

Measurements. (1 male / 1 female). Total length 7.2/6.5. Carapace length 2.57/2.37, width 1.42/1.12. Length of chelicera paturon of Male 2.77. Width of eye row I 1.27/1.15; II 1.15/1.02; III 1.31/1.20. ALE–PLE 0.95/0.83; ALE–PME 0.45/0.40. Eye size: AME 0.42/0.37; ALE 0.22/0.20; PME 0.08/0.08; PLE 0.21/0.20. Pedicel length 1.22/0.90. Abdomen length 3.55/3.10.

Distribution. Known only from Borneo.

Remarks. Myrmarachne tintinnabulum sp. nov. and M. cornuta occur sympatrically in the same habitat of the Lambir Hills National Park. Because they share most superficial characters, the identification of species is not easy in the field. The result of DNA barcoding supports the non-conspecificity of M. cornuta and M. tintinnabulum sp. nov. ( Fig. 1 ).

Figures

FIGURE 1. Neighbor-joining tree generated under K2P distance model, based on a dataset consisting of 679 bp sequences. Bootstrap values (1000 replicates) are shown beside nodes.

FIGURES 50–56. Myrmarachne tintinnabulum sp. nov., holotype male (LMy20140331_Ad1). 50 dorsal view; 51 ventral view; 52 lateral view; 53 left cheliceral paturon and fang, ventral view; 54 left palp, ventral view; 55 retrolateral view; 56 left palpal tibia, dorsal view. Scales: 50–53: 1 mm; 54–56: 0.25 mm.

FIGURES 57–64. Myrmarachne tintinnabulum sp. nov., paratype females. 57 LMy20140330_TY30, in living condition, dorsal view; 58–64 LMy20140331_Ad2. 58 dorsal view; 59 ventral view; 60 lateral view; 61 epigyne, ventral view; 62 dorsal view; 63 cleared, ventral view; 64 dorsal view. Scales. 58–60: 1 mm; 61–64: 0.1 mm.