Eterosonycha aquilina Rix & Harvey, 2010

Rix, Michael & Harvey, Mark, 2010, The spider family Micropholcommatidae (Arachnida: Araneae: Araneoidea): a relimitation and revision at the generic level, ZooKeys 36 (36), pp. 1-321 : 39-41

Eterosonycha aquilina Rix & Harvey , sp. n.

urn:lsid:zoobank.org:act:5E16DE9E-BCF3-4C19-9ABF-882338D20396

Figs 7E , 51C, 52–53

Type material. Holotype male: Yarra Ranges National Park , Mount Donna Buang, Victoria, Australia, Mountain Ash / Nothofagus /fern forest, 37°42'36"S, 145°40'57"E, 19.IV.2006, M. Rix ( NMV K10766 ).

Paratypes: Allotype female, same data as holotype ( NMV K10767 ); 4 males and 10 females, same data as holotype ( WAM T94446) .

Other material examined. AUSTRALIA: Victoria: Acheron Gap, 16 km N. of Warburton, 750 m, Nothofagus forest Berlese , 28–30.IV.1978, S. & J. Peck, 1♁ ( AMNH) ; Alfred National Park, 200 m, temperate rainforest Berlese , bark and rotten logs, 21.V.1978, S. & J. Peck, 2♁, 4♀ ( AMNH) ; Coranderrk Reserve, SE. of Healesville, 240 m, Berlese , forest litter, 13.I.1980, A. Newton, M. Thayer, 1♀ ( AMNH) ; Otway Ranges, Beauchamp Falls , sifting moss, 38°39'07"S, 143°36'23"E, 24.IV.2006, M. Rix, 1♁, 1♀ ( WAM T94444) ; Great Otway National Park, track to Cora Lynn Cascades, near Lorne , sifting moss, 38°30'58"S, 143°55'45"E, 22.IV.2006, M. Rix, 4♁, 10♀ ( WAM T94445) ; Kalista, Sherbrooke Forest Park, 400–500 m, wet sclerophyll forest Berlese of forest litter, 15.I.1980, A. Newton, M. Thayer, 1♁, 1♀ ( AMNH) ; Tarra-Bulga National Park, 550 m, Berlese , fungi on logs, 17.V.1978, S. & J. Peck, 6♀ ( AMNH) ; 12 km E. of Warburton , 215 m, Eucalyptus forest, dry moss on logs, 12–16.I.1980, A. Newton, M. Thayer, 3♀ ( AMNH) ; Warburton , 500 m, Nothofagus litter, 30.IV.1978, S. & J. Peck, 1♁ ( MCZ) ; Warburton, Cement Creek, 670 m, Nothofagus cunninghamii forest, Berlese , forest litter, 10–17.I.1980, A. Newton, M. Thayer, 1♁ ( AMNH) ; same data, 1♀ ( AMNH) ; Wingam Inlet National Park, Berlese , fungi and eucalypt bark, 23.V.1978, S. & J. Peck, 1♁ ( AMNH) . New South Wales: Kosciusko National Park, Leather Barrel Creek , 1000 m, frass under bark, wet sclerophyll, 21.IV.1978, S. & J. Peck ( AMNH) . Tasmania: 16 km NNW. of Bicheno, Douglas River , wet forest litter, 41°46'S, 148°14'E, 3.XI.1985, L. Hill, 2♀ ( QMB S6578 ) ; Cuckoo Falls, near Scottsdale , sifting moss, 41°14'13"S, 147°36'49"E, 26.IV.2006, M. Rix, 1♁, 10♀ ( WAM T94441) ; Mount Barrow Road , 890 m, Nothofagus Berlese , forest litter, 15–17.II.1980, A. Newton, M. Thayer, 2♀ ( AMNH) ; 4 km S. of Weldborough, 460 m, Nothofagus forest Berlese , 12–14.II.1980, A. Newton, M. Thayer, 1♀ ( AMNH) ; same data, 1♁ ( AMNH) .

Etymology. The specific epithet is derived from the Latin ‘aquilinus’, meaning ‘of the eagle’ ( Brown 1956), and refers to the distinctive, eagle-like shape of the female epigyne of this species.

Diagnosis. Males of Eterosonycha aquilina can be distinguished from all other described congeners by the shape of the distal conductor, which has a prominent, retrolaterally-directed process ( Fig. 53A ). Females can be distinguished from all oth- er described congeners by the distinctive, ‘eagle-like’ shape of the external epigyne ( Fig. 52D ).

Description. Holotype male: Total length 0.98. Carapace 0.47 long, 0.40 wide. Abdomen 0.66 long, 0.48 wide. Leg I femur 0.35. Cephalothorax, abdominal sclerites, legs tan-yellow; abdomen with chequered dark-olive and tan-yellow pattern laterally and ventrally. Carapace raised anteriorly, not fused to sternum except around petiole; dorsal surface of pars cephalica slightly convex in lateral view. Eight eyes present on anterior margin of pars cephalica; AME 0.6x diameter of ALE; PME separated by half their own diameter. Chelicerae each with large, bulging anterior projection; promargin with three peg teeth. Legs relatively short (leg I femur-carapace ratio 0.74); distal, prolateral macroseta present on tibia I. Abdomen oval, covered with hair-like setae; dorsal scute large, covering most of dorsal surface of abdomen; lateral sclerotic strips absent. Pedipalpal patella with retrolaterally-directed, hooked lRPA, divergent distal apophysis and expanded distal region with ornate, ridged cuticular microstructure; tibia enlarged, with pointed posterior process; tegulum large, bulging posteriorly, with excavate ETR and large, divergent, fleshy distal conductor bearing prominent, retrolaterally-directed process; embolus short (length <5× width), spur-like, situated adjacent to base of conductor ( Fig. 53 ).

Allotype female: Total length 1.09. Carapace 0.49 long, 0.39 wide. Abdomen 0.74 long, 0.57 wide. Leg I femur 0.37. Cephalothorax, abdominal sclerites, legs tan-yellow; abdomen olive brown dorsally, with chequered dark-olive and tan-yellow pattern laterally and ventrally. Carapace raised anteriorly, not fused to sternum except around petiole; dorsal surface of pars cephalica slightly convex in lateral view. Eight eyes present on anterior margin of pars cephalica; AME 0.6x diameter of ALE; PME separated by slightly less than their own diameter. Chelicerae without bulging anterior projections; promargin without peg teeth. Legs relatively short (leg I femur-carapace ratio 0.76); macrosetae absent. Abdomen oval, covered with hair-like setae; dorsal scute and lateral sclerotic strips absent. Pedipalp entire, five-segmented. Epigyne heavily sclerotised externally, with distinctive ‘eagle-shaped’ morphology ( Fig. 52D ); spermathecae looped and twisted; insemination ducts curved and looped anteriorly; fertilisation ducts filiform (Fig. 51C).

Distribution. Known from south-eastern Australia, in southern New South Wales, Victoria and Tasmania.

Remarks. Eterosonycha aquilina is among the most distinctive of any Australian Textricellini , with an unmistakeable external epigyne ( Fig. 52D ) and male pedipalp ( Fig. 53 ) morphology. It is common in moss and leaf litter in south-eastern Australia, and is one of the dominant micro-spiders in moss on Mount Donna Buang, in the Yarra Ranges of Victoria (M. Rix, pers. obs.). It can be found in sympatry with E. alpina at several localities (e.g. at Cuckoo Falls, Tasmania).

Figures

Figure 7. The genera of Micropholcommatidae, illustrated with habitus photographs of representative male specimens. A–D tribe Micropholcommatini: A Micropholcomma caeligenum Crosby & Bishop B Pua novaezealandiae Forster C Austropholcomma florentine sp. n. D Tricellina gertschi (Forster & Platnick). E–M tribe Textricellini: E Eterosonycha aquilina sp. n. F Epigastrina fulva (Hickman) G Raveniella peckorum sp. n. H Rayforstia vulgaris (Forster) I Normplatnicka lamingtonensis (Forster)] Eperiella alsophila sp. n. K Algidiella aucklandica (Forster) L Taliniella nigra (Forster) M Tinytrella pusilla (Forster). N Patelliella adusta sp. n., tribe Patelliellini. O–P subfamily Taphiassinae: O Olgania excavata Hickman P Taphiassa robertsi sp. n. Q–R subfamily Gigiellinae: Q Gigiella milledgei sp. n. R Gigiella platnicki sp. n. Note that Guiniella tropica (Forster) is not illustrated.

Figure 52. Eterosonycha aquilina sp. n. from Mount Donna Buang, Victoria. A, C holotype male (NMV K10766): A habitus, dorsal view C cephalothorax, antero-dorsal view. B, D allotype female (NMV K10767): B habitus, dorsal view D abdomen, ventral view.

Figure 53. Eterosonycha aquilina sp. n., paratype male from Mount Donna Buang, Victoria (WAM T94446): A left pedipalp, ventral view B left pedipalp, retrolateral view. Scale bar = 0.065 mm (65 µm).