Panjange lanthana

Huber, Bernhard A. & Nuñeza, Olga M., 2015, Evolution of genital asymmetry, exaggerated eye stalks, and extreme palpal elongation in Panjange spiders (Araneae: Pholcidae), European Journal of Taxonomy 169, pp. 1-46 : 6-8

Panjange lanthana group

Diagnosis

Males are easily distinguished from congeners in other species groups of Panjange by the unique processes of the genital bulb (embolus and appendix), pointing in opposite directions ( Figs 18 , 64 , 69 ). Females differ from members of the nigrifrons group by their long folded scapes ( Figs 22 , 67 , 72 ) but are in general similar to females of the cavicola group. Other leaf-dwelling pholcids in the Philippines differ from Panjange as follows: Calapnita with longer abdomen that is monochromous and dorso-posteriorly not angular; male eyes on very low humps; embolus parallel to bulbal appendix. An undescribed group of leaf-dwelling Pholcus species differs from Philippine Panjange species as follows: dorsal process on procursus; embolus parallel to bulbal appendix; short male eye stalks without pointed processes; and epigynum without long folded scape.

Description

Male

MEASUREMENTS. Total body length ~4.0–5.5; carapace width 0.9–1.2; leg 1 length ~30–45; tibia 1 length ~8.0–10.5; tibia 2/tibia 4 length 1.10–1.25; tibia 1 L/d ~95–110.

COLOR. In life ( Figs 2–15 ) mostly pale ochre-yellow to whitish, ocular area with brown mark, sternum whitish, legs with dark patellae and tibia-metatarsus joints; abdomen with dark brown to black marks dorsally and laterally, sometimes partly reddish.

BODY. Carapace without median furrow; ocular area raised, eye triads on stalks of variable length (e.g., Figs 17 , 28 , 66 , 71 ), often with pair of additional pointed processes arising from near PME (absent only in Pa. lanthana ). AME usually absent, clearly present only in Pa. lanthana , present but tiny and barely visible in Pa. camiguin Huber sp. nov. males ( Fig. 45 ). Clypeus high, either unmodiFed or with ~20–25 short spines ( Figs 84, 85 ), sometimes in addition to stronger hairs below ocular area ( Fig. 84 ). Abdomen cylindrical, angular above spinnerets ( Figs 2, 9 ). Male gonopore with four epiandrous spigots ( Figs 60 , 88 ); each ALS with large widened spigot, pointed spigot, and six cylindrically shaped spigots (of varying sizes; Figs 32 , 62 ); PMS with two spigots each ( Fig. 63 ).

CHELICERAE. With only one pair of frontal processes proximally, without distal apophyses ( Figs 17 , 47 , 84 ); without modiFed hairs; without stridulatory ridges.

PALPS. Coxa usually unmodiFed, in Pa. hamiguitan Huber sp. nov. and Pa. bukidnon Huber sp. nov. with small ventral apophysis ( Figs 65 , 92 ); trochanter and femur very variable, with species-speciFc sets of humps, short processes, and more complex apophyses; patella short to longer than wide; tibia with two trichobothria; palpal tarsus usually with whitish dorsal elongation carrying tarsal organ (e.g., Figs 19 , 25 , 65 ), rarely short (e.g., Figs 70 , 75 ), absent in Pa. bukidnon Huber sp. nov. ( Fig. 92 ); palpal tarsal organ capsulate ( Fig. 89 ); procursus usually consisting of proximal and distal part connected by membranous hinge (e.g., Figs 18 , 64 , 80 ), but not hinged in right palps of asymmetric species; parallel ridges on procursus sometimes distinct (e.g., Figs 18 , 26 , 52 ), sometimes indistinct or absent; bulb with strong proximal sclerite (e.g., Figs 18 , 69 ), with two processes pointing in opposite directions: appendix toward ventral, embolus toward dorsal.

LEGS. Without spines, without curved hairs, few vertical hairs; retrolateral trichobothrium very proximal (tibia 1: at 2–4% of tibia length), prolateral trichobothrium absent on tibia 1, present on other tibiae. Tarsus 1 with ~30 pseudosegments, sometimes very indistinct; tarsus 4 with single row of ventral combhairs of the Pholcus - type (cf. Huber & Fleckenstein 2008) ( Fig. 58 ).

Female

Similar to male but without eye stalks; eye triads on low humps ( Fig. 46 ); clypeus and chelicerae unmodiFed; legs slightly shorter than in male. Epigynum weakly sclerotized, with more or less long, folded and extensible scape directed either toward posterior or toward anterior (e.g., Figs 22 , 36 , 72 ); sometimes widened at about half length ( Figs 77 , 82 ). Internal genitalia with pair of pore plates of variable shape.

Monophyly and relationships

The monophyly of the Pa. lanthana group is consistently supported by two characters: the small ventral process distally on the proximal part of the procursus (character 17; Figs 25 , 70 ), and the unique direction of the embolus, pointing in an opposite direction than the appendix rather than lying parallel to it (character 22; Figs 18 , 64 , 69 ).

The closest relatives of the lanthana group are probably members of the Pa. cavicola group. This relationship has been suggested before ( Huber 2011) and is here supported by numerous characters: hooked rather than straight spines in ocular area (character 3; Figs 48 , 87 ); absence of distal cheliceral apophyses (character 7; Figs 17 , 47 , 66 ); strong palpal tarsal elongation (character 14; Figs 19 , 39 , 65 ); and long strongly folded epigynal scape (character 23; Figs 22 , 36 , 72 ).

Within the lanthana group, the monophyly of three species Pa. malagos Huber sp. nov. + ( Pa. casaroro Huber sp. nov. + Pa. camiguin Huber sp. nov.) is supported only by the asymmetry of the male procursus (character 9). A second species group, Pa. isarog Huber sp. nov. + ( Pa. dinagat Huber sp. nov. + Pa. marilog Huber sp. nov.) is strongly supported: male clypeus with spines (character 6; Figs 84, 85 ); male palpal tarsal process secondarily short (character 14; Figs 70 , 75 , 80 ); uncus-like process arising from proximal bulbal sclerite (character 21; Figs 70 , 80 ); and epigynal scape directed toward anterior (character 24; Figs 72 , 77 , 82 ). The sister taxa of Pa. lanthana and Pa. hamiguitan Huber sp. nov. remain unclear. In Fig. 1 , Pa. hamiguitan Huber sp. nov. is placed as sister to Pa. isarog Huber sp. nov. + ( Pa. dinagat Huber sp. nov. + Pa. marilog Huber sp. nov.), but this is weakly supported by the secondary reduction of ridges on the procursus and was not recovered in all analyses (see above).

Entirely dubious is the position of Pa. bukidnon Huber sp. nov. (excluded from the analysis for reasons detailed above; see “Cladistic analysis”). In preliminary analyses including Pa. bukidnon Huber sp. nov., it ended up at three different positions, indicated in Fig. 1 by asterisks: (1) as sister to the lanthana + cavicola groups; (2) as sister to the lanthana group; or (3) as sister to Pa. isarog Huber sp. nov. + ( Pa. dinagat Huber sp. nov. + Pa. marilog Huber sp. nov.). It shares one of the synapomorphies of the lanthana group (embolus pointing in opposite direction than appendix) but not the other (ventral process on procursus). The parallel tips of the ocular spines ( Fig. 90 ) remind of Pa. casaroro Huber sp. nov. + Pa. camiguin Huber sp. nov. while the small rounded process between appendix and genital bulb ( Fig. 91 ) reminds of Pa. dinagat Huber sp. nov. + Pa. marilog Huber sp. nov. The procursus is highly autapomorphic. It seems that only the discovery of the unknown female and/or molecular data may solve this issue.

Natural history

Most species seem to have low abundances and very patchy distributions, with few specimens found within a very small area and none in surrounding areas of apparently similar vegetation. This may have been related to the low abundance and patchiness of suitable large leaves. Specimens were usually collected between about 50 cm above ground to about 2 m, and they are likely to occur also in higher strata of the forest, possibly in higher abundances. The web is a domed sheet, most of which is closely attached to the underside of a leaf. The extremely Fne silk is poorly visible except when the sheet is viewed directly from the side. Egg sacs are only slightly elongated and covered by a barely visible layer of silk ( Figs 3, 8, 12 ). In one case ( Pa. camiguin Huber sp. nov.; Fig. 8 ), eight of ten eggs in an egg sac were parasitized by a parasitic wasp.

Composition

As construed here, the Panjange lanthana group now contains nine species (including the dubious Pa. bukidnon Huber sp. nov.). Judging from known distribution patterns and from the large number of poorly sampled islands, the group may well contain several times as many species.

Distribution

Known from the Philippines only ( Fig. 16 ).

Figures

Fig. 1. Strict consensus of two most parsimonious cladograms of Panjange Deeleman-Reinhold & Deeleman, 1983 resulting from analyses of the matrix in Appendix 1 using equal character weights, successive weighting, and implicit enumeration. Only unambiguous character changes are shown. A = clade with asymmetric male palps; * = positions of Pa. bukidnon Huber sp. nov. in preliminary cladistic analyses. See Cladistic analysis section for further details.

Fig. 16. Known distribution of the Panjange lanthana group.

Figs 17 – 19. Panjange malagos Huber sp. nov. (ZFMK, Ar 12999). 17. Male prosoma and chelicerae, frontal view. 18 – 19. Left male palp, prolateral and retrolateral views. Abbreviations: a = appendix; b = genital bulb; e = embolus; h = hinge; p = procursus; ps = proximal bulbal sclerite; pto = palpal tarsal organ; te = tarsal elongation. Scale bars = 0.5 mm.

Figs 64 – 65. Panjange hamiguitan Huber sp. nov. (ZFMK, Ar 13009), left male palp, prolateral and retrolateral views. Abbreviations: a = appendix; b = genital bulb; e = embolus; h = hinge; p = procursus; pto = palpal tarsal organ; te = tarsal elongation; vp = ventral process. Scale bar = 1 mm.

Figs 69 – 73. Panjange isarog Huber sp. nov. (ZFMK, Ar 13013, 13014). 69 – 70. Left male palp, prolateral and retrolateral views. 71. Male prosoma and chelicerae, frontal view. 72 – 73. Cleared female genitalia, ventral and dorsal views. Abbreviations: a = appendix; b = genital bulb; e = embolus; p = procursus; ps = proximal bulbal sclerite; te = tarsal elongation; tp = toothed process of proximal bulbal sclerite; tr = trochanter. Scale bars: 69 – 71 = 0.5 mm; 72 – 73 = 0.3 mm.

Figs 20 – 23. Panjange malagos Huber sp. nov. (ZFMK, Ar 12999). 20 – 21. Right male palp, prolateral and retrolateral views. 22 – 23. Cleared female genitalia, ventral and dorsal views. Scale bars = 0.5 mm.

Figs 66 – 68. Panjange hamiguitan Huber sp. nov. (ZFMK, Ar 13009, 13012). 66. Male prosoma and chelicerae, frontal view. 67. Cleared female genitalia, dorsal view (proximal part of scape partly extended). 68. Detail of Fig. 67. Scale bars: 66 – 67 = 0.5 mm; 68 = 0.3 mm.

Figs 2 – 15. Live specimens. 2 – 4. Pa. lanthana, Mt. Isarog, Ƌ, ♀ with eggsac, and penultimate Ƌ. 5. Pa. malagos Huber sp. nov., Ƌ. 6 – 7. Pa. casaroro Huber sp. nov., ƋƋ. 8 – 10. Pa. camiguin Huber sp. nov. 8. ♀ with parasitized eggsac, from Camiguin Island. 9. Ƌ from Bohol Island. 10. Ƌ from Camiguin Island. 11 – 13. Pa. dinagat Huber sp. nov., Ƌ, ♀ with eggsac, and penultimate Ƌ. 14 – 15. Pa. marilog Huber sp. nov., ƋƋ showing color variation.

Figs 26 – 30. Panjange casaroro Huber sp. nov. (ZFMK, Ar 13001). 26 – 27. Right male palp, prolateral and retrolateral views. 28. Male prosoma and chelicerae, frontal view. 29 – 30. Cleared female genitalia, ventral and dorsal views. Scale bars = 0.5 mm.

Figs 45 – 49. Panjange camiguin Huber sp. nov., SEM micrographs (ZFMK, Ar 13003, 13004). 45 – 46. Male and female prosomata, frontal views (arrows point at tiny AME remnants). 47. Male chelicerae. 48 – 49. Male eye triads and ocular processes, oblique frontal and frontal views. Scale bars: 45 – 46, 49 = 200 µm; 47 – 48 = 100 µm.

Figs 84 – 89. Panjange marilog Huber sp. nov., SEM micrographs (ZFMK, Ar 13019). 84. Male prosoma, frontal view (asterisk marks stronger hairs below ocular area). 85. Spines on male clypeus. 86. Left male palp, prolateral view. 87. Right eye stalk, triad, and hooked process, oblique frontal view. 88. Male gonopore. 89. Male palpal tarsal organ. Abbreviations: a = appendix; b = genital bulb; p = procursus; te = tarsal elongation; sp = spines on clypeus; vp = ventral process. Scale bars: 84 = 300 µm; 85 = 40 µm; 86 = 200 µm; 87 = 80 µm; 88 = 30 µm; 89 = 20 µm.

Figs 59 – 63. Panjange camiguin Huber sp. nov., SEM micrographs (ZFMK, Ar 13003, 13004). 59. Female spinnerets. 60. Male gonopore. 61. Epigynum and scape, ventral view. 62. Female ALS. 63. Female PMS. Abbreviations: ALS = anterior lateral spinneret; PLS = posterior lateral spinneret; PMS = posterior median spinneret. Scale bars: 59 = 60 µm; 60 = 30 µm; 61 = 100 µm; 62 – 63 = 10 µm.

Figs 31 – 34. Panjange casaroro Huber sp. nov., SEM micrographs (ZFMK, Ar 13001). 31. Female spinnerets. 32. Female ALS. 33 – 34. Epigynum and scape. 33. Lateral (slightly posterior) view. 34. Ventral view. Abbreviations: ALS, anterior lateral spinneret; PLS = posterior lateral spinneret; PMS = posterior median spinneret. Scale bars: 31 = 60 µm; 32 = 10 µm; 33 – 34 = 100 µm.

Figs 90 – 92. Panjange bukidnon Huber sp. nov. (ZFMK, Ar 13023). 90. Male prosoma and chelicerae, frontal view. 91 – 92. Left male palp, prolateral and retrolateral views. Abbreviations: a = appendix; b = genital bulb; e = embolus; h = hinge; p = procursus. Scale bars = 0.5 mm.

Figs 24 – 25. Panjange casaroro Huber sp. nov. (ZFMK, Ar 13001), left male palp, prolateral and retrolateral views. Abbreviations: a = appendix; b = genital bulb; e = embolus; h = hinge; p = procursus; pto = palpal tarsal organ; te = tarsal elongation; tr = trochanter; vp = ventral process. Scale bar = 0.5 mm.

Figs 74 – 78. Panjange dinagat Huber sp. nov. (ZFMK, Ar 13016). 74 – 75. Left male palp, prolateral and retrolateral views. 76. Male prosoma and chelicerae, frontal view. 77 – 78. Cleared female genitalia, ventral and dorsal views. Abbreviations: a = appendix; b = genital bulb; e = embolus; p = procursus; tr = trochanter. Scale bars: 74 – 76 = 0.5 mm; 77 – 78 = 0.3 mm.

Figs 79 – 83. Panjange marilog Huber sp. nov. (ZFMK, Ar 13019) 79 – 80. Left male palp, prolateral and retrolateral views. 81. Male prosoma and chelicerae, frontal view. 82 – 83. Cleared female genitalia, ventral and dorsal views. Abbreviations: a = appendix; b = genital bulb; e = embolus; h = hinge; p = procursus; pto = palpal tarsal organ; te = tarsal elongation; tp = toothed process of proximal bulbal sclerite; tr = trochanter; vp = ventral process. Scale bars: 79 – 81 = 0.5 mm; 82 – 83 = 0.3 mm.

Figs 50 – 58. Panjange camiguin Huber sp. nov., SEM micrographs (ZFMK, Ar 13003, 13004). 50 – 51. Left and right male palps, retrolateral views. 52. Left procursus and appendix, prolateral view. 53 – 54. Left and right male palpal trochanters and femora proximally, retrolateral views. 55. Tip of embolus. 56 – 57. Left and right procursus tips, retrolateral views. 58. Comb-hairs on female tarsus 4. Abbreviations: a = appendix; f = femur; p = procursus; sdo = sperm duct opening; te = tarsal elongation; tr = trochanter. Scale bars: 50 – 51 = 300 µm; 52 = 200 µm; 53 – 54 = 100 µm; 55 = 30 µm; 56 – 57 = 80 µm; 58 = 20 µm.

Figs 35 – 37. Panjange camiguin Huber sp. nov. (ZFMK, Ar 13003, 13004). 35. Male prosoma and chelicerae, frontal view. 36 – 37. Cleared female genitalia, ventral and dorsal views. Scale bars = 0.5 mm.

Figs 38 – 44. Panjange camiguin Huber sp. nov. (ZFMK, Ar 13003). 38 – 39. Left male palp, prolateral and retrolateral views. 40. Male chelicerae, frontal view. 41 – 42. Left male tarsus and procursus, prolateral and retrolateral views. 43 – 44. Right male tarsus and procursus, retrolateral and prolateral views. Abbreviations: a = appendix; b = genital bulb; e = embolus; p = procursus; te = tarsal elongation; tr = trochanter. Scale bars: 38 – 39, 41 – 44 = 1 mm; 40 = 0.3 mm.