Olgania Hickman, 1979

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 : 90-91

Genus Olgania Hickman, 1979

Olgania Hickman, 1979: 71 . Type species by original designation Olgania excavata Hickman, 1979 . Brignoli, 1983: 372. Davies, 1985: 55. Transferred from Anapidae to Micropholcommatidae by Platnick & Forster, 1989: 76. Platnick, 2009.

Affinities. The genus Olgania appears to be the sister-lineage to Taphiassa from Australasia ( Fig. 4 ).

Diagnosis. Species of Olgania can be distinguished from species of Taphiassa by the presence of six or fewer eyes (Figs 177C, 182C), and by the presence of a very large, wedge-shaped anterior sclerite which covers the entire anterior portion of the abdomen (Figs 176D, 177A). Other diagnostic characters include the presence of bulging anterior projections on the male chelicerae (Figs 188A, 190F), the presence of a ring of prominent sclerotic sigillae on the posterior abdomen (Fig. 177B), and the troglomorphic morphology of most species (Fig. 179).

Description. Very small, entelegyne Araneoidea : total length 0.90 to 1.20. Cephalothorax: Carapace with glandular depressions above maxillae; cuticle of carapace and sternum heavily punctate, covered with glandular pits (Fig. 188); margins fused to sternum via pleural sclerites. Six (Fig. 177C) or no (Fig. 182C) eyes present on anterior margin of pars cephalica; AME absent. Chelicerae with or (rarely) without bulging anterior projections in males; promargin with two true teeth (Fig. 190B); fused setal sockets, peg teeth and ectal stridulatory ridges absent.

Legs and female pedipalp: Legs three-clawed (Fig. 191D), covered with smooth or serrate hair-like setae. Trichobothria present on legs; tibiae each with three (legs I–III) or four (legs III–IV) trichobothria; metatarsi (legs I–III) each with single trichobothrium (Fig. 191C). Female pedipalp entire, five-segmented; claw absent (Fig. 190C–D).

Abdomen: Abdomen subtriangular in lateral view, with very large, wedge-shaped anterior sclerite present around epigastric region and petiole, extending anteriorly and laterally to cover entire anterior portion of abdomen (Figs 176D, 177A); dorsal scute absent on males and females (Fig. 176A–B); posterior abdomen thickened around dorsal and lateral margins of anterior sclerite, with ring of sclerotic sigillae (Fig. 177B) and sclerotic ring surrounding spinnerets and colulus. Six spinnerets situated posterior to fleshy colulus; ALS largest; PMS smallest; spigot morphology unknown. Anterior tracheal system well-developed, with multiple anteriorly-directed tracheae (Fig. 178A); posterior tracheal spiracle vestigial (Figs 189C–D).

Genitalia: Male pedipalp (Fig. 192) small to large; patella with retrolaterally-directed, hooked ligulate retrolateral apophysis and strongly recurved distal apophysis; tibia with or without pair of large prolateral macrosetae; tegulum smooth, with curved, marginal evaginated tegular ridge; embolus exposed, long (length> 5× width), sometimes coiled. Female genitalia (Fig. 178) with pair of separate, globular anterior receptacula each with internal ducts; insemination ducts looped or coiled; fertilisation ducts simple, curved.

Distribution. Known only from Tasmania (Fig. 213).

Composition. Olgania excavata Hickman, 1979 and the four new species O. cracroft , O. eberhardi , O. troglodytes and O. weld .

Taxonomic remarks. The genus Olgania was first described by Hickman (1979) in the family Anapidae , before being transferred to the Micropholcommatidae by Platnick and Forster (1989: 76). The close phylogenetic relationship between Olgania and Taphiassa was first noted by Rix et al. (2008), and the two genera now form the distinctive subfamily Taphiassinae .

Figures

Figure 4. Optimal cladogram for the Micropholcommatidae under equal and implied weights, and one of six equally parsimonious trees recovered from an equal weights analysis of the ‘new’ matrix (length = 135; see Appendix II). With the exception of the highlighted (*) node ‘Patelliella adusta + Micropholcommatini’, all clades shown were recovered in all iterations of an implied weights analysis (K=1–6); the phylogenetic position of P. adusta changed to ‘P. adusta + Textricellini’ under K-values 1–5. Unambiguous character optimisations are shown for each node, and bold species are newly described, with generic type species highlighted (*).