Ternatus, Sun, Ning, Li, Bin & Tu, Lihong, 2012

Sun, Ning, Li, Bin & Tu, Lihong, 2012, Te rn atu s, a new spider genus from China with a cladistic analysis and comments on its phylogenetic placement (Araneae: Linyphiidae), Zootaxa 3358, pp. 28-54 : 45-46

Ternatus new genus

Type species: Ternatus malleatus new species

Composition. Two species, Ternatus malleatus n. sp. and Ternatus siculus n. sp.

Etymology. The generic name, masculine in gender, is derived from the Latin ternate (“consisting of three”) in reference to the three tibial apophyses of the male palp.

Diagnosis. Males of Ternatus species can be distinguished from other erigonines by three well developed palpal tibial apophyses, of which the retrolateral one is furnished with modified macrosetae ( Figs. 1 E, 2E, 7A–B, 10A–D). Females are diagnosed by having the copulatory grooves forming lateral loops before entering the spermathecae ( Figs. 5 B–C, 5E–F, 8C, 8G), with their distal part opened ( Figs. 1 D, 2D, 8A, 8E).

Description. Small, male total length 2.35–2.60, female 2.38–2.67. Carapace bright orange to red, abdomen black. Male cephalic region raised with lateral sulci on sides, several setae arise from cephalic pit ( Figs. 6 A, 6C–D, 9A). AMEs smaller than other eyes; AER recurved, AME-AME shorter than AMEd, AME-ALE longer, PER straight, PME-PLE equal to PMEd, PME-PME shorter, ALE and PLE juxtaposed ( Figs. 1 A–C, 2A–C). Chelicerae with mesal surface dentate ( Figs. 6 E–F). Macrosetae on legs absent. Tm I 0.32–0.34, Tm IV absent. Female palpal claw absent. Tracheal system desmitracheate. Spinnerets ( Figs. 6 H, 9H): ALS with one major ampullate gland spigot and one nubbin; in female PLS basal part of mesal cylindrical gland spigot larger than distal one; in male PLS flagelliform and aggregate gland spigots (“araneoid triplet”) present. Epiandrous fusules absent in males.

Male palp ( Figs. 1 E–F, 2E–F, 3B–E, 4B–E, 7, 10). Palpal tibia with three apophyses: one distal, one retrolateral, and one prolateral; the retrolateral one furnished with long modified macrosetae. Paracymbium L-shaped. Tegular sac short. Distal suprategular apophysis bowl-shaped. Embolic membrane with long thread-like projections. Embolic division: radix with half rounded anterior radical process and tailpiece; embolus continuous with radix, long with basal socket, the wide basal part forming a spiral circle anterior to palpal bulb, embolic tip with hook covering the opening ( Fig. 7 H).

Epigynum ( Figs. 5 , 8 ). Dorsal plate concave resulting in centrally hollowed epigynum with plump lateral lobe at each side. Slits of epigynal grooves extending from dorsal to ventral surface with distal parts opened; no distinct trails show the location of spermathecae and boundary between fertilization grooves and copulatory grooves on the epigynal surface. Copulatory grooves forming two lateral loops before entering spermathecae. Spermathecae divided into two chambers, only one of them well developed.

Monophyly. Ternatus monophyly is unambiguously supported by the following six synapomorphies: modified setae on retrolateral tibial apophysis, distal hook on embolic tip, presence of embolic socket, distal part of copulatory groove opened, copulatory grooves forming lateral loops and presence of distal tibial apophysis.

Natural history. Ternatus species build small webs at the base of grasses, above the ground. They also can be found in the leaf-litter by sifting.

Distribution. China (Guangxi and Hunan provinces) (see map in Fig. 16 ).

Remarks. Ternatus n. gen. and Gonatium , are sister groups. They can be distinguished by the three palpal tibial apophyses in adult males: distal tibial apophysis in Ternatus arising from the anterior membranous area of palpal tibia, absent in Gonatium ; dorsal tibial apophysis arising from tibial dorsal surface in Gonatium , absent in Ternatus ; retrolateral tibial apophysis well developed and furnished with long modified macrosetae in Ternatus , small in Gonatium ; prolateral tibial apophysis long, extending distally and tightly covering over cymbium in Gonatium , free in Ternatus . Females of the two genera are different in the distal parts of copulatory grooves: opened in Ternatus , duct-like with slits opening on the epigynal surface in Gonatium , and by the tract tracings: lateral loops in Ternatus , spiral in Gonatium .

Figures

FIGURE 1. Ternatus malleatus n. sp. A, male, dorsal; B, female, dorsal; C, male, lateral; D, female epigynum, ventral; E, male palp, retrolateral; F, male palp, prolateral.

FIGURE 5. Female epigynum. A – C, Ternatus malleatus n. sp. A, ventral; B, ventral, cleared, arrow indicates lateral loop of copulatory groove; C, dorsal, cleared. D – F, Ternatus siculus n. sp. D, ventral; E, ventral, cleared; F, dorsal, cleared.

FIGURE 6. Ternatus malleatus n. sp. A – G, prosoma. A, male, lateral; B, female, lateral; C, male, dorsal, arrow indicates sulci; D, detail of A; E, female, frontal; F, detail of E (area in the box), arrow indicates dentations on chelicera; G, female chelicerae, ectal; H, male posterior lateral spinneret.

FIGURE 7. Ternatus malleatus n. sp., male palp. A, prolateral; B, retrolateral; C, anterior; D, palpal tibia, dorsal. E – H, embolic division with distal suprategular apophysis. E, ventral, arrow indicates embolic socket; F, anterior, arrow indicates embolic socket; G, anteroectal; H, distal end of embolus, arrow indicates hook on embolus apex.

FIGURE 8. Female epigynum. A – H, Ternatus malleatus n. sp., A, ventral, arrow indicates opened copulatory groove; B, dorsal; C, inner, arrow indicates lateral loop of copulatory groove; D, caudal, arrow indicates opened copulatory groove. E – F, Ternatus siculus n. sp. E, caudal, arrow indicates opened copulatory groove; F, dorsal; G, inner; H, ventral.

FIGURE 16. Collecting localities in China of Ternatus malleatus n. sp. (triangle: Huaping, Guangxi Province) and Ternatus siculus n. sp. (circle: Zhangjiajie, Hunan Province).