Patelliella adusta 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 : 78-79

Patelliella adusta Rix & Harvey , sp. n.

urn:lsid:zoobank.org:act:1AD1C743-0B7A-4F65-9AFB-CD6A34402E82

Figs 7N , 143–151, 216

Type material. Holotype male: Mount Gower summit, D Gully, Lord Howe Island, New South Wales, Australia, 850 m, moss on trees, 16.XI.1979, G. Monteith ( QMB S88030 ).

Paratypes: Allotype female, same data as holotype ( QMB S88031 ); 2 males and 1 female, same data as holotype ( QMB S88032 SEM♁ ♀); 2 females, east end of Mount Gower summit, leaf litter ex Dawsonia , moss off log, 31°35'07"S, 159°04'43"E, 15.V.2001, I. Hutton ( AMS KS79112 ) .

Other material examined. AUSTRALIA: New South Wales: Lord Howe Island: Mount Gower: far eastern edge of Little Pocket , leaf litter, 31°35'23"S, 159°04'11"E, 23.V.2002, I. Hutton, 1♀ ( AMS KS88975 ) ; midway down ridge N. of igloo, moss, 31°35'05"S, 159°04'35"E, 20.XI.2001, I. Hutton, 1♀ ( AMS KS85197 ) ; ridge, leaf litter ex moss, 31°35'18"S, 159°04'20"E, 20.XI.2001, I. Hutton, P. Flemons, C. Reid, 1♀ ( AMS KS85198 ) ; Station 45, north-eastern area of summit, in lichen on tree trunks, 31°35'12"S, 159°04'42"E, 15.II.1971, M. Gray, 1♁ ( AMS KS86058 ) ; summit, litter, 31°35'23"S, 159°04'19"E, 1.II.1979, T. Kingston, B. Miller, 2♀ ( AMS KS88977 ) ; top of gully N. of igloo, leaf litter ex moss, 31°35'07"S, 159°04'36"E, 20.XI.2001, I. Hutton, P. Flemons, C. Reid, 1♁ ( AMS KS79111 ) ; top of large ridge, 31°35'16"S, 159°04'24"E, 20.XI.2001, I. Hutton, P. Flemons, C. Reid, 1♁, 1♀ ( AMS KS79113 ) . Mount Lidgbird: 31°33'S, 159°05'E, 1978, T. Kingston, 1♁ ( AMS KS88976 ) .

Etymology. The specific epithet is derived from the Latin ‘adustus’, meaning ‘tanned’ or ‘brown’ ( Brown 1956), and refers to the brown body colouration of this species.

Diagnosis. As for the tribe Patelliellini (see above).

Description. Holotype male: Total length 1.18. Carapace 0.57 long, 0.50 wide. Abdomen 0.78 long, 0.65 wide. Leg I femur 0.47. Cephalothorax, abdominal sclerites brown; legs tan-yellow; abdomen dark-olive. Carapace significantly raised anteriorly, not fused to sternum except around petiole; dorsal surface of pars cephalica slightly convex in lateral view; clypeus bulging anteriorly. 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 each with bulging anterior projection; promargin with one peg tooth. Legs relatively short (leg I femur-carapace ratio 0.82); macrosetae absent. Abdomen oval, covered with hair-like setae; dorsal scute large, covering most of dorsal surface of abdomen; lateral sclerotic strips absent. Pedipalp as for the Tribe Patelliellini (see above).

Allotype female: Total length 1.23. Carapace 0.57 long, 0.45 wide. Abdomen 0.88 long, 0.67 wide. Leg I femur 0.43. Cephalothorax, abdominal sclerites brown; legs tan-yellow; abdomen olive. Carapace raised anteriorly, not fused to sternum except around petiole; dorsal surface of pars cephalica slightly convex in lateral view; clypeus bulging anteriorly. 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 0.75); macrosetae absent. Abdomen oval, covered with hair-like setae, each seta projecting from small sclerotic spot; dorsal scute and lateral sclerotic strips absent. Pedipalp entire, five-segmented. Epigyne as for the Tribe Patelliellini (see above).

Distribution. Known only from southern Lord Howe Island in the western Pacific Ocean, 780 km north-east of Sydney (Fig. 216).

Remarks. Patelliella adusta has been collected only from the wet, montane cloud forest that occurs on the 27 hectare summit of Mount Gower, Lord Howe Island ( Figs 220 B–E), with a single additional specimen collected from nearby Mount Lidgbird (Figs 216, 220). The species is remarkable among Micropholcommatinae in having no known close relatives, and as such its presence on Lord Howe Island is puzzling, given the recent Australasian affinities of most of the fauna and flora of the island ( Hutton 1998; Savolainen et al. 2006; Austin and Jennings 2009). Unlike the sympatric micropholcommatid species Taphiassa magna and Rayforstia lordhowensis , P. adusta has never been collected in the lowland forests on the northern half of the island, and the main population is restricted to the small, 850 m high plateau-like summit of Mount Gower (Figs 216, 220). Clearly, given its unique phylogenetic position and extremely limited distribution, this enigmatic species is of the highest conservation significance.

Subfamily Taphiassinae Rix & Harvey , subfam. n. urn:lsid:zoobank.org:act:69327955-5C5C-49FA-BA8E-71151812EABB

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 220. Lord Howe Island, western Pacific Ocean – home to three genera of Micropholcommatidae, including Patelliella adusta sp. n., the only known member of the tribe Patelliellini. A view across Lord Howe Island from Kims Lookout, showing southern mountains in the distance B Mount Lidgbird and Mount Gower from Transit Hill, showing cloud-covered summits C–E fern- and moss-covered vegetation on the summit of Mount Gower, habitat of P. adusta F lowland kentia palm rainforest at Stephens Reserve, habitat of Rayforstia lordhowensis sp. n. Images by M. Rix.