The symphytognathoid spiders of the Gaoligongshan, Yunnan, China (Araneae: Araneoidea): Systematics and diversity of micro-orbweavers
Author
Miller, Jeremy
Naturalis Biodiversity Center, Leiden, Netherlands
Author
Griswold, Charles
California Academy of Sciences ,, United States of America
Author
Yin, Chang
College of Life Sciences, Hunan Normal University ,, China
text
ZooKeys
2009
2009-05-31
11
11
9
195
journal article
10.3897/zookeys.11.160
6bed073a-175c-42e6-bb99-645c99d55b4f
1313–2970
576459
C631A347-306E-4773-84A4-E4712329186B
Family
Symphytognathidae Hickman, 1931
Symphytopgnathids are typically characterized by cheliceral fusion, a sternum broadly truncated posteriorly, reduction of the female palp and eye number, and the absence of book lungs (
Forster and Platnick 1977
,
Wunderlich 2004
). However, some sym- phytognathid genera have the chelicerae fused only at the base (e.g.,
Patu
,
Curmagua
Forster and Platnick 1977
) and the distinction between basally fused chelicerae and unfused chelicerae can be subtle. The remaining characters are present in other symphytognathoid families so enumerating synapomorphies for the family is problematic.
At least the symphytognathid species described here also share with anapids an insertion of the pedicel on the posterior slope of carapace (as typically associated with
Anapidae
; e.g.
Jocqué and Dippenaar-Schoeman 2006
) rather than the pleural region between carapace and sternum. Epiandrous gland spigots, present in theridiosomatids, mysmenids, and synaphrids, are absent from anapids and symphytognathids.
Crassignatha
is the only symphytognathid in which the male has an abdominal scutum, a trait more typical of
Anapidae
. The presence of a single tooth-like keel on the chelicerae and the lack of a fang furrow has been used in part to diagnose
Synaphridae
(
Lopardo et al. 2007
,
Miller 2007
). Some
Patu
(
Fig. 69
E-F) and
Crassignatha
(
Fig. 78A
) species exhibit these same characteristics.
Another character of possible interest for circumscribing
Symphytognathidae
concerns the situation of the aggregate gland spigots on a common base (Figs 71D, 85D, 92D;
Griswold et al. 1998
: figs 35D, 36D).
The presence of a colulus is homoplasious within some symphytognathid genera (
Forster and Platnick 1977
). A colulus is absent at least from
P. jidanweishi
and
Crassignatha
(investigated in
C. quanqu
sp. n.
and
C. longtou
sp. n.
). Some other
Patu
species do have a small colulus (e.g.
Griswold et al. 1998
: figs 23A, 37A).
The symphytognathid species described here are placed in the genera
Patu
and
Crassignatha
Wunderlich, 1995
.
Patu
is a particularly problematic genus. Comparative anatomy of the genitalia across the genus has been rudimentary, a problem exacerbated by the scarcity of material in collections and the minute size of these animals. In practice,
Patu
are symphytognathids with minimal fusion of the chelicerae and 1-3 teeth (
Forster 1959
,
Forster and Platnick 1977
,
Saaristo 1996
). However, at least two of the
Patu
species described here have a distinctive cluster of 2-4 strong setae on the distoventral part of the male tibia II. Similar structures have been described for
Patu samoensis
Marples, 1951
and are found in
Crassignatha
.
Crassignatha
was cataloged in the
Mysmenidae
, apparently based on the presence of cymbial lobes and mating claspers. However, the distal cymbial tooth found in
Crassignatha
does not interact with the embolus as a functional conductor, as is typically the case in mysmenids. Also, the mating claspers in
Crassignatha
are on the distoventral part of tibia II; mating claspers in
Mysmenidae
are always found on the prolateral face of metatarsus and/or tibia I.
Diagnosis
.
Symphytognathidae
distinguished from other spider families in the Gaoligongshan except
Anapidae
by the following combination of characters: the lack of a female pedipalp (
Fig. 70C
) and male epiandrous gland spigots (
Fig. 78E
), and by the insertion of the pedicel through an opening in the posterior declavity of the carapace (
Fig. 65B
,
74B
); distinguished from
Anapidae
by the fusion of the chelicerae at least at the base (
Figs 69F
,
78A
) and by having the aggregate gland spigots arise from a common base (Figs 71D, F, 92D). Like
Anapidae
and unlike most other spiders,
Symphytognathidae
typically have the tarsi longer than the metatarsi (
Figs 74E
,
83E
), but the tarsi are rarely as much as 1.5 times the length of the metatarsi.