Taphiassa Simon, 1880

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 : 80-82

Genus Taphiassa Simon, 1880

Taphiassa Simon, 1880: 172 . Type species by monotypy Taphiassa impressa Simon, 1880 . Roewer, 1942: 414. Bonnet, 1959: 4238. Transferred from Theridiidae to Symphytognathidae by Levi & Levi, 1962: 29. Transferred from Symphytognathidae to Mysmenidae by Forster & Platnick, 1977: 2. Brignoli, 1980: 730 (also transferred ‘ Taphiassa ’ punctigera Simon, 1895 to Theridiidae incertae sedis). Brignoli, 1983: 379. Platnick, 2009.

Parapua Forster, 1959: 301 . Type species by original designation Parapua punctata Forster, 1959 . Brignoli, 1983: 374. Platnick, 2009. syn. n. (but see also Brignoli, 1980: 731).

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

Diagnosis. Species of Taphiassa can be distinguished from species of Olgania by the presence of a normal, plate-like anterior sclerite (Fig. 165C), the presence of an enlarged subtegulum (Fig. 174A), and the presence of a seta projecting from the proximal toothed mound of the cheliceral promargin (Figs 159B, 172F). Other diagnostic characters include the presence of eight eyes (Fig. 152A), and the absence of bulging anterior projections on the male chelicerae (Fig. 157E).

Description. Very small, entelegyne Araneoidea : total length 1.00 to 2.20. Cephalothorax: Carapace with glandular depressions above maxillae (Figs 170E, 170G– H); cuticle of carapace and sternum heavily punctate, covered with glandular pits (Figs 152A–C); margins fused to sternum via pleural sclerites. Eight eyes present on anterior margin of pars cephalica (Fig. 152A); eyes usually subequal, AME greater than three-quarters diameter of ALE (Fig. 152C). Chelicerae without bulging anterior projections in males; promargin with one sessile tooth and separate proximal, toothed mound near tip of fang bearing prolateral seta (Figs 159A–B); fused setal sockets, peg teeth and ectal stridulatory ridges absent.

Legs and female pedipalp: Legs three-clawed (Figs 160E–F), covered with smooth or serrate hair-like setae; superior claws of legs I–II often strongly pectinate (Figs 173D– E); superior claws of legs III–IV usually asymmetric (Fig. 173F). Trichobothria present on legs; tibiae each with three (legs I–III) or four (legs III–IV) trichobothria; metatarsi each with (legs I–IV) (Fig. 160C) or sometimes without (leg IV) single trichobothrium. Female pedipalp entire (Fig. 159C), reduced or vestigial (Fig. 170F); claw absent (Fig. 159D).

Abdomen: Abdomen globose; anterior sclerite present around epigastric region and petiole; dorsal scute absent on males and females (Figs 155A–B); posterior sclerotic ring surrounding spinnerets and colulus. Six spinnerets situated posterior to fleshy colulus (Figs 162, 175); PMS with single medial AC gland spigot and posterior seta; PLS with reduced triad consisting of FL gland spigot and single AG gland spigot. Anterior tracheal system well-developed, with multiple radiating tracheae (Figs 169E–F); posterior tracheal spiracle vestigial (Figs 152F, 154D).

Genitalia: Male pedipalp (Figs 161, 174) relatively small; patella with retrolaterallydirected, hooked ligulate retrolateral apophysis and strongly recurved distal apophysis; subtegulum enlarged, bulging posteriorly; tegulum smooth, with curved evaginated tegular ridge; embolus exposed, long (length> 5× width), curving distally. Female genitalia (Figs 154A–C, 169) with pair of separate, globular anterior spermathecae; insemination ducts simple, straight; fertilisation ducts simple, curved.

Distribution. Eastern and south-western mainland Australia, Tasmania, Lord Howe Island, New Caledonia and New Zealand (Fig. 217).

Composition. Two described species, Taphiassa impressa Simon, 1880 and T. punctata ( Forster, 1959) and the four new species T. castanea , T. globosa , T. magna and T. robertsi . Undescribed species are also known from New Caledonia and eastern Australia. Note that the species Taphiassa punctigera Simon, 1895 is a Theridiidae incertae sedis ( Brignoli 1980; Platnick 2009), not conspecific or congeneric with T. impressa .

Nomenclatural remarks. The genus Taphiassa was originally described by Simon (1880) for the species T. impressa , from Nouméa, New Caledonia. No illustrations were provided with the original description, and the species had never been adequately illustrated ( Brignoli 1980). Levi and Levi (1962) transferred T. impressa from the Theridiidae to the Symphytognathidae , while Forster and Platnick (1977) transferred it from the Symphytognathidae to the Mysmenidae . It was Brignoli (1980) who, with remarkable insight aided only be Simon’s original Latin description, first noted the similarity of T. impressa to Parapua , and the analysis of Rix et al. (2008) also inferred a close sister-group relationship between Taphiassa and Parapua . Taphiassa is hereby transferred from the Mysmenidae to the Micropholcommatidae , and Taphiassa is formally recognised as a senior generic synonym of Parapua .

Taxonomic remarks. Species of Taphiassa can be arbitrarily divided into two groups based upon somatic features – the ‘ Taphiassa group’ and the ‘ Parapua group’. Species in the ‘ Parapua group’ (including T. punctata , T. castanea and similar species) are generally smaller, darker coloured, with relatively shorter legs and smaller female pedipalps than species in the ‘ Taphiassa group’, which are often relatively large with strongly patterned abdomens. A spectrum of intermediate morphologies exists, however, and the division seems merely phenetic. Many additional species of Taphiassa are known from Australia and New Caledonia (e.g. see Platnick 1993 under “ Parapua ”), and the genus has clearly radiated in New Caledonia, with at least five undescribed species represented in museum collections (M. Rix, unpubl. data).

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 (*).