Arnapa tinoor Huber, 2019

Huber, Bernhard A. & Carvalho, Leonardo S., 2019, Filling the gaps: descriptions of unnamed species included in the latest molecular phylogeny of Pholcidae (Araneae), Zootaxa 4546 (1), pp. 1-96 : 24-30

Arnapa tinoor Huber sp. n.

Figs 43–44 , 65–69 , 74 , 87–89 , 95–104

Gen.n. Ind82: Eberle et al. 2018 (molecular data); Huber et al. 2018: fig. 2.

Type material. INDONESIA: ♂ holotype, ZFMK (Ar 20614), Sulawesi, North Sulawesi, Tinoor Fall near Tomohon (1.3820°N, 124.8363°E), 500 m a.s.l., at rocks near waterfall, 2.xi.2009 (S. Sutono) .

Other material examined. INDONESIA: 25♂ 29♀ 7 juvs, ZFMK (Ar 20615–16) and 2♀ 1 juv. in pure ethanol, ZFMK (Ind 184), same data as holotype . 4♂ 2♀, ZFMK (Ar 20617) and 1♂ 3♀ 1 juv. in pure ethanol, ZFMK (Ind 194), North Sulawesi, degraded forest at Danau ( Lake ) Linow near Tomohon (1.2653°N, 124.8310°E), 880 m a.s.l., 3.xi.2009 (S. Sutono) . 5♂ 9♀ 6 juvs, RMNH, North Sulawesi, Dumoga [~ 0.5°N, 123.95°E], primary forest, 27–30.vii.1982 (collector not given) .

Etymology. The species name is derived from the type locality; noun in apposition.

Diagnosis. Males are easily distinguished from known congeners by modified clypeus ( Fig. 68 ; rounded median process); also by armature of male chelicerae ( Fig. 68 ; ~6 lateral apophyses in a row plus ~7 apophyses proximally in a patch), and by shapes of bulbal process and procursus distal elements ( Figs 67, 69 ); females differ from known congeners by combination of small plate in front of epigynum, absence of strong transversal ridges on epigynum, very short posterior epigynal plate, and relatively small pore plates ( Figs 74 , 87–89 ).

Description. Male (holotype). MEASUREMENTS. Total length 2.2, carapace width 1.05. Distance PME-PME 90 µm; diameter PME 100 µm; distance PME-ALE 80 µm; distance AME-AME 20 µm, diameter AME 45 µm. Leg 1: 27.9 (6.6 + 0.4 + 6.9 + 11.9 + 2.1), tibia 2: 3.9, tibia 3: 2.8, tibia 4: 3.9; tibia 1 L/d: 73.

COLOR (in ethanol). Carapace ochre-yellow with dark brown bands laterally and wide band medially including ocular area; clypeus with pair of dark bands below eye triads; sternum ochre-yellow with pair of slightly darker marks near median line; legs brown, with indistinct darker rings on femora (subdistally) and tibiae (proximally and subdistally), tips of femora and tibiae whitish. Abdomen gray, dorsally densely covered with dark marks, ventrally with slightly darker mark in gonopore area, dark median band behind gonopore, pair of brown external marks and pair of larger internal ventro-lateral marks in front of spinnerets.

BODY. Habitus as in Fig. 43 . Ocular area elevated, thoracic furrow present; clypeus with median rounded process ~100 µm long ( Fig. 68 ), possibly provided with glands ( Fig. 98 ). Sternum wider than long (0.68/0.40), unmodified. ALS with only two spigots each, one widened, one pointed ( Fig. 97 ). Gonopore without epiandrous spigots ( Fig. 101 ).

CHELICERAE. As in Fig. 68 , with several sclerotized cones in distinctive arrangement: large cones in a lateral row ( Fig. 99 ) and smaller cones in a frontal patch ( Fig. 100 ); without modified hairs; with stridulatory ridges ( Fig. 99 ).

PALPS. As in Figs 65–66 ; coxa unmodified, trochanter with short ventral process weakly sclerotized, femur strongly widened, with large rounded retrolateral process proximally, with stridulatory pick (modified hair) proximally and stronger than usual hairs distally on ventral-retrolateral side, patella ventrally reduced (not closed), tibia retrolateral trichobothrium in very proximal position, tarsus small, tarsal organ exposed ( Fig. 102 ), procursus with dorsal process proximally, ventrally slightly concave but without pocket, distally with distinctive sclerotized and membranous elements ( Fig. 67 ), with brush of hair-like structures on prolateral side ( Fig. 104 ); genital bulb large, with complex process carrying sperm duct opening ( Figs 69 , 103 ).

LEGS. Without spines; few vertical hairs; with curved hairs on femora, tibiae, and metatarsi of all legs (especially legs 1–2); retrolateral trichobothrium of tibia 1 at 9%; prolateral trichobothrium present on all tibiae; tarsus 1 with ~25 pseudosegments, distally distinct.

Male (variation). Number of sclerotized cones on chelicerae slightly variable but pattern consistent. Tibia 1 in 28 males: 4.9–7.6 (mean 6.6).

Female. In general similar to male but clypeus unmodified; chelicerae without stridulatory ridges (confirmed by SEM). Tibia 1 in 37 females: 3.8–5.1 (mean 4.5). Epigynum as in Figs 87 and 95 , anterior plate divided medially by variably distinct whitish area, with additional smaller plate in front of anterior epigynal plate; posterior plate very short but wide. Internal genitalia with distinctive lateral folds and narrow anterior ‘valve’, relatively small pore plates ( Figs 74 , 89 ). ALS as in male ( Fig. 96 ).

Distribution. Known from three localities in North Sulawesi ( Fig. 343 ).

Natural history. At Tinoor Fall ( Fig. 337 ), this species was found in high abundance on the wet steep rock wall at the waterfall. Their domed webs had a diameter of ~ 15 cm and were built in small cavities and among small plants on the rock; they were often densely covered by tiny water droplets. Above the waterfall, the spiders were abundant on the undersides of dead leaves on the ground. At Danau Linow, the spiders were found both in leaf litter and in a much dryer habitat, on the stems of palm trees up to 1 m and more above the ground, with their webs among the dense mesh of palm fibers.

Figures

FIGURE 343. Known distribution of Arnapa gen. n.; red marks: undescribed species. Further undescribed species that might belong in this genus are known from the Caroline Islands and from Papua New Guinea east to the Louisiade Archipelago.

FIGURES 39–44. Arnapa spp., live specimens. 39–40. A. arfak sp. n., male and female from Mokwam. 41–42. A. tolire sp. n., male and female with egg sac from Ternate. 43–44. A. tinoor sp. n., male and female from near Tomohon.

FIGURES 65–69. Arnapa tinoor sp. n. (ZFMK, Ar 20615). 65–66. Left male palp, prolateral and retrolateral views. 67. Left procursus, dorsal view. 68. Male prosoma, oblique frontal view. 69. Left genital bulb, dorsal view. Scale lines: 0.5.

FIGURES 70–74. Arnapa spp., cleared female genitalia, dorsal views. 70. A. arfak sp. n. (ZFMK, Ar 20605). 71. A. manokwari sp. n. (ZFMK, Ar 20608). 72. A. meja sp. n. (ZFMK, Ar 20610). 73. A. tolire sp. n. (ZFMK, Ar 20613). 74. A. tinoor sp. n. (ZFMK, Ar 20616). Scale lines: 0.3.

FIGURES 81–89. Arnapa spp., epigyna, ventral views, and cleared female genitalia, ventral and dorsal views. 81–83. A. meja sp. n. (ZFMK, Ar 20610). 84–86. A. tolire sp. n. (ZFMK, Ar 20613). 87–89. A. tinoor sp. n. (ZFMK, Ar 20616). Scale lines: 0.5.

FIGURES 90–97. Arnapa tolire sp. n. (90–94, ZFMK, Ar 20613) and A. tinoor sp. n. (95–97, ZFMK, Ar 20615–16). 90–91. Female prosoma, frontal views. 92. Left female palp and chelicerae; note absence of stridulatory files. 93. Female palpal tarsal organ. 94–95. Epigyna, ventral views. 96–97. Female and male spinnerets. ALS, anterior lateral spinneret; ch, chelicera; PMS, posterior median spinneret; pto, palpal tarsal organ. Scale lines: 10 µm (93, 96–97), 100 µm (90–92, 94–95).

FIGURES 98–104. Arnapa tinoor sp. n., male (ZFMK, Ar 20615). 98. Projection on clypeus; note presence of putative pores. 99. Cheliceral stridulatory ridges and lateral processes. 100. Cheliceral frontal proximal processes. 101. Gonopore. 102. Palpal tarsal organ. 103. Left procursus and bulb, dorsal view; arrow points at sperm duct opening. 104. Distal part of procursus, prolateral view. ba, bulbal apophysis; gb, genital bulb; pr, procursus. Scale lines: 10 µm (98–100, 102, 104), 20 µm (101), 100 µm (103).

FIGURES 336–341. Selection of collecting sites and habitats. 336. Forest above Mokwam (West Papua), type locality of Arnapa arfak sp. n. and Aetana mokwam sp. n. 337. Tinoor Fall near Tomohon (North Sulawesi), type locality of Arnapa tinoor sp. n. 338. Entrance to Caverna Porco do Mato II (Rio Grande do Norte), type locality of Pinocchio barauna sp. n. 339. Desert between Sur and Kamil (Oman), type locality of Magana velox sp. n. 340. Bromeliad at Reserva Particular do Patrimônio Nacional Serra Bonita (Bahia), type locality of Psilochorus bromelicolus sp. n. (note pair of spiders among leaves). 341. Disturbed forest near Sofifi (Halmahera), type locality of Giloloa sofifi sp. n. and Panjange togutil sp. n.