Olgania troglodytes 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 : 94-96

Olgania troglodytes Rix & Harvey , sp. n.

urn:lsid:zoobank.org:act:12301C34-1B39-4A2A-AC50-A018051969AB

Figs 178C, 179D, 184–185, 213

Type material. Holotype male: Revelation Cave (IB-1), Ida Bay karst, Tasmania, Australia, under sheet webs on wall of side chamber upslope from main cave passage, c. 40 m below surface (dark zone), 25.III.1989, A. Clarke ( AMS KS32002 ).

Paratypes: Allotype female, same data as holotype ( AMS KS97163 ); 1 male and 3 females, same data as holotype ( AMS KS97164 ) .

Other material examined. AUSTRALIA: Tasmania: Arthurs Folly (1B-110), Ida Bay karst, in sheet web on moist wall c. 2 m above stream (dark zone), before rockfall section c. 200 m from entrance, 43°24'S, 146°52'E, 20.XI.1986, A. Clarke, S. Eberhard, 1♁, 2♀ ( AMNH) ; Bradley-Chesterman Cave (IB-4), Ida Bay karst, from sheet webs (twilight zone), 43°24'S, 146°52'E, 22.III.1990, S. Eberhard, 4♀ ( QVM 13 : 13223) ; Dismal Hill Pot (IB-128), Ida Bay karst, webs near leaf litter at ̴ 90 m below surface (dark zone), 9.VIII.1987, S. Eberhard, 2♁ ( AMS KS20185 ) ; Little Grunt (IB-23), Ida Bay karst, 43°24'S, 146°52'E, from webs on cave ceiling (dark zone), 16. IV.1990, S. Eberhard, 1♀ ( QVM 13 : 13066) ; same data except webs on dry cave wall, 20.XI.1990, 2♀ ( QVM 13 : 12768) ; Loons Cave (IB-2), Ida Bay karst, sheet webs (from near litter or in mud cracks) near aven (dark zone), 10.V.1989, S. Eberhard, J. Jackson, 1♁, 2♀ ( AMS KS29595 ) ; same data except in sheet webs deep in cave (dark zone), 2♀ ( QVM 13 : 12665) ; March Fly Pot (IB-46), Ida Bay karst, from sheet-webs on walls in lower chamber (dark zone), 43°24'S, 146°52'E, 23.III.1990, S. Eberhard, 2♁, 2♀ ( QVM 13 : 13303) ; Pseudocheirus Cave (IB-97), Ida Bay karst, 4.V.1990, S. Eberhard, 3♁, 7♀ ( QVM 13 : 12851) ; Straw Cave (IB-91), Ida Bay karst, from sheet webs deep in cave (dark zone), 43°24'S, 146°52'E, 5.IV.1990, S. Eberhard, 1♀ ( QVM 13 : 13268) ; Thun Junction (IB-20), Ida Bay karst, from horizontal web in crevice of aven wall at c. 35 m depth, 125 m from entrance (dark zone), 24.III.1989, A. Clarke, 2♀ ( AMS KS32011 ) .

Etymology. The specific epithet is derived from the Greek ‘trogle’, meaning ‘hole’, and the Greek ‘dytes’, meaning ‘enterer’ ( Brown 1956), and refers to the cave-dwelling nature of this species.

Diagnosis. Males of Olgania troglodytes can be distinguished from all other described congeners except O. cracroft by the absence of prolateral, thorn-like macrosetae on the male pedipalpal tibia; and from O. cracroft by the shorter, looped embolus (Fig. 185). Females can be distinguished from all other described congeners by the distinctive shape of the receptacula (Fig. 178C).

Description. Holotype male: Total length 0.94. Carapace 0.42 long, 0.41 wide. Abdomen 0.63 long, 0.47 wide. Leg I femur 0.76. Cephalothorax, abdominal sclerites tan-yellow; legs pale tan-yellow; abdomen cream. Carapace raised anteriorly, fused to sternum via pleural sclerites; dorsal surface of pars cephalica strongly convex in lateral view; carapace and sternum heavily punctate. Eyes absent, except for single, barely-visible vestigial eye spot on each side of pars cephalica. Chelicerae without bulging anterior projections; promargin without peg teeth. Legs relatively long (leg I femur-carapace ratio 1.81); macrosetae absent. Abdomen subtriangular-globose, covered with hair-like setae, each seta projecting from small sclerotic spot; dorsal scute and lateral sclerotic strips absent. Pedipalpal patella with retrolaterally-directed, hooked lRPA, strongly recurved distal apophysis and additional, flange-like distal process; tibia without thorn-like macrosetae; tegulum smooth, with curved, marginal ETR; embolus long (length> 5× width), looping around prolateral margin of bulb (Fig. 185).

Allotype female: Total length 0.96. Carapace 0.46 long, 0.42 wide. Abdomen 0.67 long, 0.54 wide. Leg I femur 0.78. Cephalothorax, abdominal sclerites tan-yellow; legs pale tan-yellow; abdomen cream. Carapace raised anteriorly, fused to sternum via pleural sclerites; dorsal surface of pars cephalica strongly convex in lateral view; carapace and sternum heavily punctate. Eyes absent, except for single, barely-visible vestigial eye spot on each side of pars cephalica. Chelicerae without bulging anterior projections; promargin without peg teeth. Legs relatively long (leg I femur-carapace ratio 1.70); macrosetae absent. Abdomen subtriangular, covered with hair-like setae, each seta projecting from small sclerotic spot; dorsal scute and lateral sclerotic strips absent. Pedipalp entire, five-segmented. Epigyne with distinctive external morphology (Fig. 184D); receptacula globular, with coiled internal ducts; insemination ducts looped; fertilisation ducts simple, curved (Fig. 178C).

Distribution. Known only from caves in the Ida Bay karst of southern Tasmania, including Arthurs Folly, Bradley-Chesterman Cave, Dismal Hill Pot, Little Grunt, Loons Cave, March Fly Pot, Pseudocheirus Cave, Revelation Cave, Straw Cave and Thun Junction (Fig. 213).

Remarks. Olgania troglodytes is a distinctive, blind and long-legged species known from at least 10 caves in the Ida Bay karst of southern Tasmania. It is among the most troglomorphic of any Micropholcommatidae , and is most similar to O. cracroft from the nearby Cracroft karst (Fig. 179). Nothing is known of its biology or conservation status, except that specimens were collected from horizontal sheet-webs on the walls of caves.