Arnapa 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 : 15-16

Arnapa Huber gen. n.

Type species. Arnapa arfak sp. n.

Etymology. The genus is named for West Papuan cultural leader and musician Arnold Ap (1946–1984); gender feminine.

Diagnosis. Distinguished from similar Southeast Asian and Australian Arteminae ( Wugigarra , Holocneminus , Trichocyclus ) by the combination of: (1) male palpal tarsus dorsally with whitish area (e.g., Huber 2001: figs 201, 248, 265; absent in Wugigarra ); (2) genital bulb without worm-shaped process (present in Wugigarra and some Holocneminus ; e.g., Huber 2001: figs 16, 24); (3) legs with curved hairs (absent in Trichocyclus ); (4) genital bulb without transparent dorsal process (present in most Trichocyclus , e.g., Huber 2001: figs 191, 203, 252); (5) ALS with only two spigots each ( Figs 96, 97 ; 8–9 spigots in Holocneminus and Trichocyclus ; e.g. Huber 2001: figs 195, 209, 224); (6) male clypeus unmodified or with round median process (pair of strong horns in Holocneminus ; e.g., Deeleman-Reinhold 1995: fig. 2; Beatty et al. 2008: fig. 7); (7) carapace with median and lateral dark bands ( Figs 39–44 ; three pairs of marks in most Holocneminus and Trichocyclus ; e.g. Huber 2001: fig. 187; Deeleman- Reinhold 1995: fig. 1; Beatty et al. 2008: fig. 34); (8) female chelicerae without stridulatory ridges ( Fig. 92 ; present and distinct in Wugigarra and Holocneminus ; e.g. Huber 2011: figs 45, 139); (9) epigynum without light median projection ( Figs 75, 78 , 81, 84, 87 ; present in Trichocyclus ; e.g. Huber 2001: figs 200, 213, 240).

Description. Male. MEASUREMENTS. Total body length 2.0–2.3, carapace width 0.9–1.1. Leg 1: ~25–35, tibia 1: 4.9–8.0; tibia 1 L/d: ~70–100. Distance PME-PME 75–110 µm, diameter PME 80–110 µm, distance PME- ALE 60–120 µm, distance AME-AME 15–20 µm, diameter AME 40–50 µm.

COLOR. In general ochre to brown ( Figs 39, 41, 43 ). Carapace with dark brown median and lateral marginal bands, never with three pairs of dark marks. Clypeus with pair of brown bands. Legs usually with dark rings on femora subdistally, patellae + tibiae proximally, and tibiae subdistally; tips of femora and tibiae whitish. Abdomen always with dark marks and sometimes also white marks dorsally and laterally; ventrally with dark mark behind gonopore.

BODY. Habitus as in Figs 39, 41, 43 . All eyes on raised ocular area. Carapace with distinct median furrow, without pit. Clypeus unmodified or slightly more prominent than in females, only in A. tinoor with rounded median projection ( Fig. 68 ). Chelicerae with cone-shaped apophyses in species-specific arrangement, always with distinct stridulatory ridges. Gonopore without epiandrous spigots ( Fig. 101 ). ALS with one strongly widened and one long pointed spigot each ( Fig. 97 ); PMS with two spigots each; PLS without spigots.

PALPS. Large relative to body size. Coxa unmodified. Trochanter barely modified or with short ventral projection. Femur strongly widened, with retrolateral process proximally. Patella on ventral side not closed. Retrolateral trichobothrium of tibia in relatively proximal position. Tarsus dorsally with whitish area, with exposed tarsal organ ( Fig. 102 ). Procursus with distinct dorsal process, with species-specific distal sclerotized and membranous elements. Bulb with complex and species-specific process carrying sperm duct opening, never with worm-shaped process.

LEGS. Without spines; few vertical hairs; with curved hairs, especially on tibiae and metatarsi; retrolateral trichobothrium on tibia 1 at 4–11%; prolateral trichobothrium present on all tibiae; tibia 2 and tibia 4 approximately same length; pseudosegmentation of tarsi distally distinct.

Female. In general similar to male ( Figs 40, 42, 44 ) but legs shorter (tibia 1: 3.8–6.7), stridulatory files on chelicerae either absent or very fine. Epigynum with weakly sculptured anterior plate and distinct posterior plate, sometimes with dark median sclerite anteriorly.

Monophyly. The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) included four representatives of Arnapa and a total of 12 representatives of Wugigarra , Holocneminus , and Trichocyclus . Arnapa was recovered with maximum support, but there is no obvious morphological character that is likely to provide a synapomorphy for the genus. The diagnosis above shows that similarities exist with each of the three closely related genera, but in the absence of a comprehensive cladistic analysis it is generally not known which character states are plesiomorphic and which apomorphic.

Generic Relationships. The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) supports a close relationship between Arnapa and three other Southeast Asian and Australian Arteminae genera ( Wugigarra , Holocneminus , Trichocyclus ). However, relationships among these four genera remain unresolved.

Composition/Diversity. The genus currently includes six species: the five species newly described below, plus Arnapa nigromaculatus ( Kulczyński, 1911) comb. n. that is newly transferred from Psilochorus . The latter species originates from Indonesia, West Papua, “Manikion” (~ 1.49°S, 133.94°E). The only known specimen (male holotype) could not be found at the Museum and Institute of Zoology of the Polish Academy of Sciences, Warsaw (W. Wawer, pers. comm. July 2018). Kulczyński’s (1911) reasonably good drawings of the male palp suggest that it is likely to be closely related to the species newly described below but not conspecific with the geographically close A. arfak , nor with any of the other four species described below.

Several additional species exist in collections (Institut Royal des Sciences Naturelles de Belgique, Brussels; Natural History Museum, London; and Netherlands Centre for Biodiversity Naturalis, Leiden). The Pholcidae of New Guinea are extremely poorly known and it seems likely that the island is home to many dozen species of this genus.

Distribution. Widely distributed in eastern Indonesia ( Fig. 343 ). Further undescribed species that might belong in this genus are known from the Caroline Islands and from New Guinea east to the Louisiade Archipelago.

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 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 7–12. Artema spp., procursi in dorsal views, and genital bulbs in dorsal views. 7–8. A. bahla sp. n. (ZFMK, Ar 20587). 9–10. A. ghubrat sp. n. (ZFMK, Ar 20594). 11–12. A. dhofar sp. n. (ZFMK, Ar 20596). a, b, c, bulbal processes a–c; da, dorsal apophysis; em, embolus; n, light notches. Scale line: 0.5 (all figures at same scale).

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 75–80. Arnapa spp., epigyna, ventral views, and cleared female genitalia, ventral and dorsal views; arrows point at internal putative pockets. 75–77. A. arfak sp. n. (ZFMK, Ar 20605). 78–80. A. manokwari sp. n. (ZFMK, Ar 20608). Scale lines: 0.5.

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 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 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).