The phylogeny of pholcid spiders: a critical evaluation of relationships suggested by molecular data (Araneae, Pholcidae)
Author
Huber, Bernhard A.
Author
Eberle, Jonas
Author
Dimitrov, Dimitar
text
ZooKeys
2018
789
51
101
http://dx.doi.org/10.3897/zookeys.789.22781
journal article
http://dx.doi.org/10.3897/zookeys.789.22781
1313-2970-789-51
496949FCA96A4489A0940182520DAB6C
496949FCA96A4489A0940182520DAB6C
Pholcinae
'group 1'
Figs 7, 8
Remarks
.
This group includes some genera named long ago, like
Spermophora
,
Belisana
, and
Paramicromerys
Millot, 1946. Most other genera were described relatively recently and resulted either from splitting of
Spermophora
(e.g.,
Spermophorides
Wunderlich, 1992;
Buitinga
Huber, 2003;
Savarna
Huber, 2005;
Khorata
Huber, 2005) or from the discovery and description of new species (
Aetana
Huber, 2005;
Wanniyala
Huber & Benjamin, 2005;
Hantu
Huber, 2016).
A Southeast Asian clade that is consistently resolved with high to full support but variably placed either inside 'group 1' (IQ-TREE, RogueNaRok) or outside of the three operational groups as an isolated fourth group (4+ genes, RAxML) is composed of
Aetana
, Southeast Asian '
Spermophora
', and an undescribed new genus from Indonesia (
"Ind206"
). Morphological data have suggested a close relationship of
Aetana
with
Savarna
,
Khorata
, and
Hantu
(
Huber et al. 2015
). The positions of those three genera in our molecular trees are all unstable and problematic (see below). Thus, we consider it premature to conclude that the morphological data were misleading, and suggest that the positions of
Savarna
,
Khorata
, and
Hantu
need further analysis. A similar problem occurs with Southeast Asian '
Spermophora
'. The monophyly of the five species included receives reasonable to high support, but this group does not seem to be close to the type species
S. senoculata.
However, the position of
S. senoculata
varies strongly among analyses, and the idea that Southeast Asian taxa are in fact congeneric with
S. senoculata
(
Huber 2005a
) should not yet be discarded based on the present molecular data.
In
Aetana
, our analyses include 16 of 18 (89%) described species plus two undescribed species. The monophyly of the genus is highly to fully supported even though morphological support appeared weak (
Huber et al. 2015
). All four species groups proposed after cladistic analysis of morphological characters (
Huber et al. 2015
) are supported, but with different relationships among each other. Most of these relationships among species groups receive low support, but the kiukoki group is resolved as sister of the omayan group (with modest support) and this is in conflict with the results from morphology (
Huber et al. 2015
). The two unnamed subgroups within the
kinabalu
group and within the omayan group, respectively, proposed in
Huber et al. (2015)
are all recovered (with modest to full support).
The next clade within 'group 1' (Figure 7) includes three taxa whose position varies strongly among different analyses (see above): the type species of
Spermophora
,
S. senoculata
, and the Southeast Asian genera
Khorata
and
Savarna
.
Spermophora senoculata
is alternatively resolved as sister to the African '
Spermophora
'
akwamu
group (RAxML) or to the African '
Spermophora
'
kyambura
Huber & Warui, 2012 (4+ genes, RogueNaRok). Its sister group is essentially unknown. As indicated above, a close relationship with Southeast Asian '
Spermophora
', even though never recovered by our analyses, should not be definitely discarded.
Khorata
and
Savarna
are sister taxa in some analyses (low support; IQ-TREE, RogueNaRok), but wide apart in
others
. The former result is considered more plausible for two reasons: (1) morphology supports a close relationship between
Khorata
and
Savarna
(
Huber et al. 2015
); (2) the alternative topology (4+ genes, RAxML) places the Southeast Asian
Savarna
as sister to an East African clade.
The large Asian genus
Belisana
(Figure 8) is well represented in our analyses (30 species) but seems to suffer from rogue taxa, paralogs, and/or other unidentified problems. Only the RogueNaRok tree resolves a monophyletic
Belisana
. In other analysis, either
Hantu
(RAxML) or
Hantu
and '
Spermophora
'
kyambura
are nested within
Belisana
(IQ-TREE). A close relationship between
Belisana
and
Hantu
(that is also suggested in the RogueNaRok tree) is strongly contradicted by morphology: several
characters
support a close relationship between
Hantu
,
Khorata
, and
Savarna
(
Huber et al. 2015
). We have no explanation for the position of
Hantu
in our trees. Intriguingly,
H. niah
Huber, 2016 (but not
H. kapit
Huber, 2016) was placed in a clade together with
Khorata
and
Savarna
in preliminary analyses of the present data. On the other hand, the African '
Spermophora
'
kyambura
might indeed be close to
Belisana
. In fact, had it been collected in Southeast Asia, it would probably have been assigned to
Belisana
. It was tentatively assigned to
Spermophora
because African '
Spermophora
' were polyphyletic anyway and because the closest known record of
Belisana
was from India, more than 5000 km east. However, the position of '
Spermophora
'
kyambura
varies among analyses and should be considered unresolved.
Our sample of
Belisana
includes numerous representatives from different microhabitats (litter and leaves) and with different types of webs (
'usual'
pholcid domed sheets and highly regular
'curtain'
webs; Figs 8
e-f
; see also
Deeleman-Reinhold 1986a
,
Huber 2005b
). The present data suggest multiple microhabitat shifts within
Belisana
, but note that many nodes within the genus have very low support values. These low values also impede a proper interpretation of the fact that the two species with a
'usual'
domed web (marked with D in Figure 8) included in the analyses (
B.
"Mal77"
,
B. tambligan
Huber, 2005) are not
'basal'
but nested among species with highly regular
'curtain'
webs (marked with R in Figure 8) [confirmed for
B. bohorok
Huber, 2005;
B. leuser
Huber, 2005;
B.
"Bor85"
;
B. junkoae
(Irie, 1997);
B. sabah
Huber, 2005; BA Huber, unpubl. data].
Except for the Sri Lankan genus
Wanniyala
, all remaining taxa of
Pholcinae
'group 1' (Figure 7) are African, Madagascan, and Mediterranean. They are grouped together but with very low support. South African and Madagascan '
Spermophora
' were not available for sequencing and are thus not included in our analyses; we predict they are members of this clade. As mentioned above, some analyses (RAxML, 4+ genes) placed the East Asian genus
Savarna
within this clade; we consider this topology dubious.
A close relationship between the West African '
Spermophora
'
tonkoui
group and
Wanniyala
is suggested in all our analyses, even though with low support (only SH values are consistently at 96-97). This relationship is also supported by morphology: the two taxa share a hinged procursus with a membranous process arising from the proximal part (see
Huber and Benjamin 2005
: fig. 7,
Huber 2003b
: fig. 293,
Huber and Kwapong 2013
: fig. 101).
The following clade (Figure 7) places the Central African '
Spermophora
'
awalai
group as sister to the Macaronesian and Mediterranean genus
Spermophorides
, both together sister to the Madagascan genus
Paramicromerys
, and all together sister to an undescribed Madagascan genus (
"CAS13"
). Support for these relationships is modest, and the clade is different in composition in the 4+ genes tree (
Spermophorides
is missing from this analysis).
The last clade in
Pholcinae
'group 1' is highly to fully supported in all analyses and includes the East African genus
Buitinga
and East African '
Spermophora
', each with full support in all analyses. The sister group relationship between these two taxa makes sense geographically but is not evident from morphology.