Arnapa tinoor Huber

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

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Arnapa tinoor Huber

sp. n.

Arnapa tinoor Huber  sp. n.

Figs 43–44View FIGURES 39–44, 65–69View FIGURES 65–69, 74View FIGURES 70–74, 87–89View FIGURES 81–89, 95–104View FIGURES 90–97View FIGURES 98–104

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)GoogleMaps  .

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 holotypeGoogleMaps  . 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)GoogleMaps  . 5♂ 9♀ 6 juvs, RMNH, North Sulawesi, Dumoga [~ 0.5°N, 123.95°E], primary forest, 27–30.vii.1982 (collector not given)GoogleMaps  .

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. 68View FIGURES 65–69; rounded median process); also by armature of male chelicerae ( Fig. 68View FIGURES 65–69; ~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, 69View FIGURES 65–69); 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 74View FIGURES 70–74, 87–89View FIGURES 81–89).

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. 43View FIGURES 39–44. Ocular area elevated, thoracic furrow present; clypeus with median rounded process ~100 µm long ( Fig. 68View FIGURES 65–69), possibly provided with glands ( Fig. 98View FIGURES 98–104). Sternum wider than long (0.68/0.40), unmodified. ALS with only two spigots each, one widened, one pointed ( Fig. 97View FIGURES 90–97). Gonopore without epiandrous spigots ( Fig. 101View FIGURES 98–104).

CHELICERAE. As in Fig. 68View FIGURES 65–69, with several sclerotized cones in distinctive arrangement: large cones in a lateral row ( Fig. 99View FIGURES 98–104) and smaller cones in a frontal patch ( Fig. 100View FIGURES 98–104); without modified hairs; with stridulatory ridges ( Fig. 99View FIGURES 98–104).

PALPS. As in Figs 65–66View FIGURES 65–69; 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. 102View FIGURES 98–104), procursus with dorsal process proximally, ventrally slightly concave but without pocket, distally with distinctive sclerotized and membranous elements ( Fig. 67View FIGURES 65–69), with brush of hair-like structures on prolateral side ( Fig. 104View FIGURES 98–104); genital bulb large, with complex process carrying sperm duct opening ( Figs 69View FIGURES 65–69, 103View FIGURES 98–104).

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 87View FIGURES 81–89 and 95View FIGURES 90–97, 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 74View FIGURES 70–74, 89View FIGURES 81–89). ALS as in male ( Fig. 96View FIGURES 90–97).

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

Natural history. At Tinoor Fall ( Fig. 337View FIGURES 336–341), 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.