The spider family Micropholcommatidae (Arachnida: Araneae: Araneoidea): a relimitation and revision at the generic level
Author
Rix, Michael
Western Australian Museum, Welshpool DC, Perth, Australia
Author
Harvey, Mark
Western Australian Museum, Perth, Welshpool, Australia
text
ZooKeys
2010
2010-02-22
36
36
1
321
journal article
10.3897/zookeys.36.306
4db6b327-7482-432e-a5f6-36f91c79fef3
1313–2970
576620
ADCACC88-6C78-4386-8E33-3F98234ECE92
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
.