Tissahamia karuna, Huber, 2019

Huber, Bernhard A., 2019, The pholcid spiders of Sri Lanka (Araneae: Pholcidae), Zootaxa 4550 (1), pp. 1-57 : 27

Tissahamia karuna sp. n.

Figures 97–98 , 107–111 , 116–117 , 120–121

Diagnosis. Males are easily distinguished from most similar species ( T. maturata Huber, 2011 ) by details of palp: coxa with finger-shaped ventral process ( Fig. 109 ); prolateral process of main bulbal process (‘appendix’) small and weakly sclerotized ( Fig. 117 ); procursus shorter, without sclerotized prolateral process between proximal and distal elements and with larger distal elements ( Fig. 110 ). Females are barely distinguishable from T. maturata but seem to have consistently more weakly sclerotized epigyna and the anterior epigynal margin more curved ( Fig. 120 ).

Etymology. The species name is derived from the Pāli word karuṇā, one of the four Buddhist virtues or brahmavihāras (identifying the suffering of others as one's own); noun in apposition.

Type material. SRI LANKA: ♂ holotype, ZFMK (Ar 20065), Western Province, Labugama Forest (6.846°N, 80.175°E), 150 m a.s.l., 20.iii.2017 (B.A. Huber) .

Other material examined. SRI LANKA: 1♂ 1♀, NMSL , 6♂ 8♀, ZFMK ( Ar 20066–67), and 4♀ in pure ethanol, ZFMK ( SL167 ), same data as holotype . 3♂ 3♀, ZFMK ( Ar 20068), and 1♂ 2♀ in pure ethanol, ZFMK ( SL97 ), Western Province, Mitirigala Forest (6.997°N, 80.175°E), 70 m a.s.l., 6.iii.2017 (B.A. Huber) . 2♀ in pure ethanol, ZFMK ( SL105 ), Sabaragamuwa Province, near Kitulgala (6.985°N, 80.430°E), 170 m a.s.l., 7.iii.2017 (B.A. Huber) . 1♀, ZFMK (Ar 5088) (this female was erroneously assigned to Pholcus maturat a in Huber 2011), Western Province, Avissawella [6.953°N, 80.218°E], 3.viii.1996 (S.P. Benjamin) .

Description. Male (holotype). MEASUREMENTS. Total body length 4.4, carapace width 1.0. Distance PME- PME 400 µm, diameter PME 100 µm, distance PME-ALE 40 µm; AME absent. Sternum width/length: 0.63/0.47. Leg 1: 37.9 (8.8 + 0.4 + 9.0 + 17.6 + 2.1), tibia 2: 5.9, tibia 3: 3.3, tibia 4: 5.3; tibia 1 L/d: 113. Femora 1–4 width (at half length): all 0.09.

COLOR (in ethanol). Carapace mostly dark brown to black, including ocular area and clypeus, only lateral margins and beside ocular area whitish; sternum brown; legs pale ochre-yellow, patellae and tibia-metatarsus joints dark brown to black; abdomen pale with dark marks dorsally and laterally, ventrally monochromous.

BODY. Habitus as in Fig. 97 ; ocular area slightly raised, each triad on short stalk, with curved pointed process (~100 µm long) arising from median margin of each PME; with small process (~20 µm long) in place of AME; carapace without median furrow; clypeus and sternum unmodified.

CHELICERAE. As in Fig. 116 , with pair of weakly sclerotized processes proximally, without distal modification.

PALPS. As in Figs 107–109 ; coxa with finger-shaped ventral process (longer than in T. maturata and T. kottawagamaensis ; cf. Huber 2011: figs 805–806; Dong et al. 2016: figs 5A–B); trochanter with short retrolaterodorsal and longer pointed retrolatero-ventral apophyses, very similar to T. kottawagamaensis ; femur with dorsal hump and ventral process pointing toward proximal; tarsus with whitish elongation with tarsal organ at its tip; procursus complex ( Figs 110–111 ), with bifid dorsal process partly covered retrolaterally by transparent membrane, prolateral tip of bifid process connected to strong ridge that leads to ventral ‘knee’ and borders ventral pocket; distally with ventral hinged sclerite; genital bulb with simple membranous embolus and large heavily sclerotized bulbal process (‘appendix’) with small weakly sclerotized prolateral process ( Fig. 117 ).

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 3%; prolateral trichobothrium absent on tibia 1; tarsus 1 pseudosegments not seen.

Male (variation). Tibia 1 in 9 other males: 6.8–9.0 (mean 8.2). Males from Mitirigala with slightly wider tip of appendix and with small conical process on proximal part of bifid dorsal process of procursus (asterisk in Fig. 110 ).

Female. In general similar to male but carapace mostly light with small U-shaped dark mark ( Fig. 98 ), triads closer together (distance PME-PME 210 µm), without processes arising from near PME, without small process in place of AME. Tibia 1 in 13 females: 6.4–7.2 (mean 6.8). Epigynum as in Fig. 120 ; with weakly sclerotized epigynal plate and finger-shaped semi-transparent process (‘knob’) arising at anterior margin on epigynal plate (not visible in Fig. 120 ); whitish rugose area in front of epigynal plate bordered anteriorly by dark internal arc (‘valve’) visible through cuticle. Internal genitalia as in Fig. 121 , with pair of oval pore plates.

Natural history. This species built its domed web connected to the underside of live leaves. Webs were sometimes shared with many cecidomyiid flies. At Labugama, the spiders were found in the forest as well as in very disturbed secondary vegetation.

Distribution. Known from four localities in southwestern Sri Lanka ( Fig. 225 ).

Figures

FIGURES 93–102. Tissahamia, live specimens. 93–96. T. ethagala (Huber, 2011), male from Ethagala, female with egg-sac from Kandalama, and females from Dematagala. 97–98. T. karuna sp. n., male and female with egg-sac from Labugama. 99– 100. T. maturata (Huber, 2011), male with mite and female with egg-sac from Hakgala. 101–102. T. kottawagamaensis (Yao & Li, 2016), male from Kottawa, female from Viharekele.

FIGURES 103–109. 103–106. Tissahamia ethagala (Huber, 2011), female prosomata in dorsal views (both specimens from Dimbulagala, ZFMK Ar 20059) and ventral views (specimens from Dimbulagala and Ethagala, ZFMK Ar 20059 and 20056). 107–109. T. karuna sp. n. (ZFMK Ar 20066), left male palp in prolateral, dorsal, and retrolateral views. Abbreviations: a, ‘appendix’ (main bulbal process); b, genital bulb; c, coxa; e, embolus; f, femur; p, procursus; pbs, proximal bulbal sclerite; ta, tarsus; ti, tibia; tr, trochanter. Scale line (107–109): 0.5 mm (103–106 at various scales).

FIGURES 110–115. Left procursi in prolateral (upper row) and retrolateral views, all images at same scale. 110–111. Tissahamia karuna sp. n., from Labugama (ZFMK Ar 20066); asterisk marks area where males from Mitirigala have a small conical process. 112–113. T. maturata (Huber, 2011), from Hakgala (ZFMK Ar 20069); arrow points at distinctive prolateral process. 114–115. T. kottawagamaensis (Yao & Li, 2016), from Kottawa (ZFMK Ar 20072). Abbreviations: bp, bifid process; hs, hinged sclerite; m, membrane; po, pocket; r, ridge; ta, tarsus. Scale line: 0.5 mm.

FIGURES 116–119. 116–117. Tissahamia karuna sp. n., from Labugama (ZFMK Ar 20066), male chelicerae, frontal view; and processes of left genital bulb, prolateral view. 118–119. T. maturata (Huber, 2011) from Hakgala (ZFMK Ar 20069) and T. kottawagamaensis (Yao & Li, 2016) from Kottawa (ZFMK Ar 20072), processes of left genital bulbs in prolateral views (all genital bulbs at same scale). Abbreviations: a, ‘appendix’ (main bulbal process); e, embolus. Scale lines: 0.3 mm.

FIGURES 120–125. Epigyna in ventral views (upper row) and cleared female genitalia in dorsal views. 120–121. Tissahamia karuna sp. n., from Labugama (ZFMK Ar 20067); arrow points at internal arc (‘valve’). 122–123. T. maturata (Huber, 2011), from Hakgala (ZFMK Ar 20070). 124–125. T. kottawagamaensis (Yao & Li, 2016), from Kottawa (ZFMK Ar 20073). Abbreviation: pp, pore plate. At various scales.

FIGURES 224–225. Known distribution of Tissahamia in Sri Lanka; “?”, female with uncertain identity from Eastern Sinharaja.