Pholcinae 'group 3'

Huber, Bernhard A., Eberle, Jonas & Dimitrov, Dimitar, 2018, The phylogeny of pholcid spiders: a critical evaluation of relationships suggested by molecular data (Araneae, Pholcidae), ZooKeys 789, pp. 51-101: 69-79

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http://dx.doi.org/10.3897/zookeys.789.22781

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Pholcinae 'group 3'
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Pholcinae 'group 3'  Figs 9, 10, 11, 12

Remarks.

A sister-group relationship between the African genus Quamtana  and the Pholcus  group of genera (Figure 9) is recovered in all our analyses. Support values are low, but a morphological cladistic analysis has partly suggested the same relationship (based on a distinct sclerite connecting the genital bulb to the palpal tarsus; Huber 2003c). The monophyly of Quamtana  is highly supported in all analyses (except for the 4+ genes analysis). It was also supported by morphological data when using character weighting (but not in the equal weights analysis; Huber 2003c).

Within Quamtana  (Figure 9), our data suggest that there is no simple geographic pattern with respect to South African species (the large majority) versus species from other parts of Africa (marked in Figure 9). By contrast, three species groups with reasonable to full support include species from both South Africa and other regions: the South African Q. filmeri  Huber, 2003 is sister to the Madagascan undescribed species “CAS5”; the South African Q. vidal  Huber, 2003 and Q. umzinto  Huber, 2003 are placed in a group with species from East and Central Africa ( Q. kabale  Huber, 2003, “Cam117”); and the group including the South African Q. embuleni  Huber, 2003 and Q. bonamanzi  Huber, 2003 also includes species from East and Central Africa ( Q. kitahurira  Huber, 2003, Q. oku  Huber, 2003). We suspect that Quamtana  was once widely distributed throughout Africa but largely replaced by more modern taxa in humid regions and extinguished in northern Africa. The Paris amber fossil Quamtana huberi  Penney, 2007 supports this view, but its generic assignment is uncertain ( Penney 2007).

All remaining clades together (Figs 10-12) represent the Pholcus  group of genera sensu Huber (2011a). This clade was first proposed in Huber & Fleckenstein (2009) based on the distinctive simplified shape of the tarsus IV comb-hairs, and later supported in a cladistic morphological analysis by an additional character (female epigynal ‘knob’) ( Huber 2011a). All our analyses fully support this clade. The previous morphological analysis ( Huber 2011a) identified two major problems within this clade: (1) relationships among genera were basically unresolved, resulting in large polytomies; and (2) several species groups assigned to Pholcus  appeared more closely related to other genera. The present analysis strongly supports the polyphyly of Pholcus  in its previous composition, and it provides for the first time a reasonable framework to redefine generic limits in this large group (currently 501 species).

The first major clade within the Pholcus  group of genera (Figure 10) is composed of three Southeast Asian genera ( Calapnita  , Panjange  , Uthina  Simon, 1893) as well as several Southeast Asian and Sri Lankan species groups that were originally tentatively assigned to Pholcus  ( Huber 2011a; Huber et al. 2016a, 2016b, Huber and Dimitrov 2014). We informally call it the ' Calapnita  - Panjange  clade’ because many species in this group are leaf-dwellers, and representatives of Calapnita  and Panjange  are particularly strongly adapted to life on green leaves. Remarkably, even some of the species collected in the leaf litter (under large dead leaves on the ground) look like leaf-dwellers rather than litter dwellers (i.e., they have long abdomens, long legs, light colouration; e.g., Kintaqa satun  (Huber, 2011) and K. schwendingeri  (Huber, 2011); and Malaysian representatives of Tissahamia  , previously the Pholcus ethagala  group). Ancestral character state reconstruction suggests that the ancestor of the entire clade was leaf-dwelling ( Eberle et al. 2018).

The present analyses reject the monophyly of Calapnita  (Figure 10). A recent cladistic analysis of morphological data ( Huber 2017) resolved Calapnita  as monophyletic but with low support (< 50 using Jackknifing). On the other hand, support for the two subgroups, previously called phyllicola group and vermiformis  group, is full in all analyses. The two species groups have been identified long ago ( Deeleman-Reinhold 1986b), and have been supported by cladistic analysis ( Huber 2017). Our analyses strongly suggest that the vermiformis  group is closer to species previously in Pholcus  than to the phyllicola group (see below). The phyllicola group is thus elevated to genus rank ( Nipisa  ; see Taxonomy section below).

Within Nipisa  (Figure 10), the internal relationships proposed previously ( Huber 2017) are mostly supported even though data gaps are severe in this genus (several species with only two genes): (1) N. lehi  (Huber, 2017) [but not N. kubah  (Huber, 2017)] is a ‘basal’ species, i.e., sister to all other species (reasonable to high support); (2) a clade including the species with egg-sacs that have all eggs aligned in a single row (weak support, possibly because N. kubah  is included, which is contradicted by morphology and egg-sac shape); (3) a clade including N. semengoh  (Huber, 2011) and its sister group, characterized by the position of the tarsal organ on a turret, a serrate embolus, and the shape of the pore-plates (full support).

The relationships within ‘true’ Calapnita  (previously vermiformis  group) proposed in Huber (2017) are only partly supported: (1) a clade with a continuous connection between epigynal plate and ‘knob’ (all species in the present analysis except C. bario  Huber, 2017 and C. saluang  Huber, 2011; high support); (2) within the previous clade, a clade characterized by a prolateral process at the tip of the procursus (in the present analysis: C. nunezae  Huber, 2017 and C. dinagat  Huber, 2017; full support).

The present analyses also reject the monophyly of Panjange  (Figure 10). They split the genus into two unrelated lineages, one of which is equivalent to what was previously called the nigrifrons group; the other is equivalent to the previous vermiformis  + cavicola groups ( Deeleman-Reinhold and Platnick 1986, Huber and Nuñeza 2015). Our analyses place each group with reasonable to full support in clades together with species previously assigned to Pholcus  . A morphological cladistic analysis has recently supported the monophyly of Panjange  based on the presence of parallel ridges ventrally on the procursus and on the reduction of the bulbal uncus ( Huber and Nuñeza 2015). However, the monophyly was lost when using specific weighting parameters (implied weighting with K = 1 and K = 2), and some morphological characters do in fact support the split of Panjange  : (1) the loss of distal cheliceral apophyses in ‘true’ Panjange  and its closest relatives according to the present analyses; (2) the loss of an uncus in ‘true’ Panjange  and its closest relatives according to the present analyses. The nigrifrons group is thus elevated to genus rank ( Apokayana  ; see Taxonomy section below).

Apokayana  is recovered with full support. This is remarkable considering the fact that in the morphological analysis its equivalent (the Panjange nigrifrons  group) was supported by a single homoplastic character only ( Huber and Nuñeza 2015). Within the genus, our analyses identify two subgroups with full support each. These groups do not correspond to the relationships suggested in Huber and Nuñeza (2015). In that analysis, each node was based on a single character, some of them not particularly convincing. We thus tend to prefer the present grouping even though our matrix is particularly incomplete in this genus (we did not manage to get 28S and CO1 sequences for any of the six species included).

The monophyly of ‘true’ Panjange  ( vermiformis  + cavicola groups) is supported by several morphological characters ( Huber and Nuñeza 2015), and receives high support in our present analyses (except for the 4+ genes analysis). The cavicola group (including also the two undescribed species “Ind103” and “Ind109”) was recovered as paraphyletic in Huber and Nuñeza (2015) but is here resolved as monophyletic. By contrast, the lanthana group which was supported by two morphological characters, one of them considered particularly strong (the unique direction of the embolus, pointing in the opposite direction of the appendix) is resolved as monophyletic only in the RogueNaRok tree; in the IQ-TREE and RAxML trees it is paraphyletic with respect to the cavicola group (actually, these trees suggest a basal trichotomy). Within the lanthana group, three species ( P. malagos  Huber, 2015; P. casaroro  Huber, 2015; P. camiguin  Huber, 2015) share asymmetric male pedipalps, a character that is extremely rare in spiders ( Huber et al. 2007, Huber and Nuñeza 2015). This group is not recovered in any of the present analyses, where it consistently includes the symmetric P. lanthana  Deeleman-Reinhold & Deeleman, 1983 (requiring a regain of symmetry or two origins of asymmetry). Only the sister group relationship between P. dinagat  Huber, 2015 and P. marilog  Huber, 2015 is strongly supported by both morphology and molecules. In conclusion, alternative topologies within the lanthana group are supported by seemingly strong molecular and morphological data, respectively.

Ten species groups previously assigned to Pholcus  (in Huber 2011a, Huber et al. 2016a, 2016b) are representatives of the ' Calapnita  - Panjange  clade’ (Figure 10). Of these, nine are entirely Southeast Asian; only the ethagala group (now Tissahamia  ) has representatives in Southeast Asia and Sri Lanka. For some of these species groups, our data provide strong evidence about the sister-group or close relatives. All of these groups are here transferred from Pholcus  to new genera (see Taxonomy section below).

A sister-group relationship between Kelabita  (previously the Pholcus andulau  group) and Apokayana  (previously the Panjange nigrifrons  group) is fully supported in all our analyses (except for the 4+ genes tree where Kelabita  is not represented). Both genera are restricted to Borneo and share habitus, colouration, web structure, and microhabitat ( Huber and Leh Moi Ung 2016, Huber et al. 2016a).

The western Indonesian ' Pholcus kerinci  group’ ( Huber 2011a) and the Philippine ' Pholcus domingo  group’ ( Huber et al. 2016b) are both fully supported, as is their sister-group relationship (Figure 10). They are joined in the new genus Teranga  (see Taxonomy section below). Together with Tissahamia  (previously the Pholcus ethagala  group) and with ‘true’ Panjange  they form a clade that is recovered in all analyses with reasonable support. This clade was supported in almost exactly the same composition by morphological cladistic analysis ( Huber 2011a) except that the ' Panjange  ' nigrifrons  group was also included (the ' Pholcus domingo  group’ was not yet known in 2011). The clade is supported by the loss of the bulbal uncus and by the loss of distal male cheliceral apophyses [in Huber 2011a, the latter character supports a more inclusive taxon (including Leptopholcus  Simon, 1893) that is strongly rejected by the present molecular data]. Tissahamia  consists of two subgroups, a Sri Lankan subgroup and a Southeast Asian (Malaysian Peninsula, Sumatra) subgroup. The subgroups are consistently recovered in all our analyses with modest to reasonable support, but the monophyly of the entire group is only recovered in the IQ-TREE analysis (low support). Morphological analysis recovered the group, but with varying support depending on weighting regime ( Huber 2011a).

Three genera composed of species that were previously assigned to Pholcus  are consistently placed in a highly supported clade together with ‘true’ Calapnita  (Figure 10): Paiwana  (previously not assigned to a group), Muruta  (previously the Pholcus tambunan  group; Huber et al. 2016b), and Meraha  (previously the Pholcus krabi  group; Huber et al. 2016b). We know of no convincing morphological synapomorphy for this group but note two interesting similarities: representatives of ‘true’ Calapnita  and of Meraha  share the loss of piriform gland spigots on the anterior lateral spinnerets ( Huber 2011a, 2017, Huber et al. 2016b); representatives of ‘true’ Calapnita  and of Muruta  and Paiwana  share the distinctive shape of the epigynum (roughly triangular, with ‘knob’ directed towards anterior; Huber et al. 2016b, Huber 2017; Huber and Dimitrov 2014).

For two further genera composed of species previously assigned to Pholcus  the present analysis supports the monophyly but gives not clear indication about their closest relatives within the ' Calapnita  - Panjange  clade’ (Figure 10): Pribumia  (previously the Pholcus minang  group; Huber 2011a) and Kintaqa  (previously the Pholcus buatong  group; Huber et al. 2016a). All analyses except the IQ-TREE analysis place Kintaqa  as sister to Uthina  , but with low support. We know of no potential morphological synapomorphy that links these two groups. Pribumia  is in our analysis represented by four species. Of these, P. diopsis  (Simon, 1901) is never placed within the group; together with P. atrigularis  (Simon, 1901) it is detected as a rogue taxon and excluded in the RogueNaRok tree. External relationships of Pribumia  remain dubious. The hypothesis that the genus might be close to Tissahamia  (previously the ' Pholcus ethagala  group’; Huber 2011a) is supported by numerous distinctive morphological similarities but it is not supported by the present data. However, note that in our analysis Pribumia  suffers seriously from missing data (we were not able to sequence 28S for any of the four species).

The second major clade within the Pholcus  group of genera (Figure 11) is composed of four ‘old’ genera ( Micropholcus  ; Leptopholcus  ; Micromerys  Bradley, 1877; Pehrforsskalia  Deeleman-Reinhold & van Harten, 2001) and Cantikus  (previously the Pholcus halabala  group; Huber 2011a, Huber et al. 2016a). Except for one clade of Neotropical Micropholcus  , all representatives are Old World taxa. We informally call it the ' Micropholcus  Leptopholcus  clade’. This clade receives full support in all our analyses, and major internal relationships are also well resolved. Three subclades are fully supported each: Micropholcus  ; Cantikus  ; and a subclade including Leptopholcus  , Micromerys  , and Pehrforsskalia  . All analyses put Micropholcus  as sister to Cantikus  , but with modest support.

Micropholcus  is ecologically diverse, including ground-dwelling as well as rock- and leaf-dwelling species, and together with Pholcus  it is also the only genus with autochthonous species in both the New and Old World. Our analysis rejects the previous idea that Micropholcus  is ‘basal’ in the Pholcus  group of genera (i.e., in a basal trichotomy, with Sihala  occupying the second branch and all other taxa the third branch; Huber 2011a). Within Micropholcus  , our analyses all support a monophyletic New World clade, but with low support values (reasonable support in the 4+ genes analysis). Within the New World clade, a Caribbean clade is fully supported. A remarkable sister-group relationship that is highly supported by the present data is between the Moroccan ' Pholcus  ' agadir  (now transferred to Micropholcus  ; see Taxonomy section below) and the undescribed Philippine species “Phi114”. Both have very limited distributions; only one further species of Micropholcus  (other than the pantropical M. fauroti  ) is known from between Morocco and the Philippines: M. jacominae  Deeleman-Reinhold & van Harten, 2001 from Yemen. We suspect that Micropholcus  in the Old World has a relict distribution, just as it has been hypothesized for South American Micropholcus  ( Huber et al. 2005a, 2014).

Cantikus  was recently revised (as ' Pholcus  ' halabala  group; Huber et al. 2016a) and divided into a 'core group’ that was supported by numerous morphological and behavioral similarities, and a group of species that were assigned to the group tentatively. This tentative assignment was based mainly on preliminary results from the present molecular analysis; a putative morphological synapomorphy for the entire genus Cantikus  was and is not known. The present analyses fully support both the entire genus and the core group; the genus includes C. quinquenotatus  (Thorell, 1878), making the quinquenotatus group proposed in Huber (2011a) obsolete; and it highly to fully supports the sister group relationship between the two rock-dwelling species C. kuhapimuk  Huber, 2016 and C. khaolek  Huber, 2016.

The clade including Leptopholcus  , Micromerys  , and Pehrforsskalia  (Figure 11) was only partly supported in a previous cladistic analysis of morphological data ( Huber 2011a): while Leptopholcus  and Micromerys  were consistently seen as sister taxa (with a mono- or paraphyletic Leptopholcus  ), the position of Pehrforsskalia  varied widely. The characters supporting a close relationship among the three genera are the distal position of the lateral apophyses on the male chelicerae, and the absence of frontal cheliceral apophyses ( Huber 2011a). The present analyses fully support this clade. Within the clade, ‘basal’ relationships are unresolved, essentially resulting in a tetrachotomy: (1) ' Leptopholcus  ' podophthalmus  (Simon, 1893) is not clearly included in ‘true’ Leptopholcus  . (2) The Australasian Micromerys  receives full support in all analyses. (3) The African Pehrforsskalia  is only represented by its type species. (4) ‘True’ Leptopholcus  receives reasonable to full support and includes both African and Asian representatives but not the Asian L. podophthalmus  (and its putative close relative L. tanikawai  Irie, 1999 that is not included in our analyses). Within Leptopholcus  , our data provide little resolution, but an Asian clade (represented by L. borneensis  Deeleman-Reinhold, 1986 and L. kandy  Huber, 2011) receives reasonable support. Among these four clades, Pehrforsskalia  is the only one that does not share the distinctively serrated tip of the male palpal trochanter apophysis ( Huber 2011b), suggesting that it may be sister to the other three clades.

The third and last major clade within the Pholcus  group of genera is ‘true’ Pholcus  (Figure 12). Support for this group is very low in the IQ-TREE analysis, which reflects the fact that one of the two basal subclades (including the phungiformes and bidentatus groups and P. mentawir  Huber, 2011) is closer to the Micropholcus  - Leptopholcus  clade than to ‘true’ Pholcus  in some analyses (RAxML, RogueNaRok). By contrast, the 4+ genes analysis recovers the monophyly of ‘true’ Pholcus  with reasonable support, suggesting that the poor support or non-monophyly of ‘true’ Pholcus  in some analyses may result from the many missing data in our full matrix.

Even after removing the eleven species groups that are here placed in the Calapnita  Panjange  clade and in the Micropholcus  Leptopholcus  clade, Pholcus  continues to be the most species rich genus in Pholcidae  . It now contains 321 species, most of which are distributed in tropical and subtropical Old World regions. The only exception is the kingi group with ten species in the southeastern USA ( Huber 2011a). Most species of Pholcus  resemble the synanthropic type species P. phalangioides  in being relatively large, long-legged, brown, and in having a cylindrical abdomen; most or all of these species build their webs in large sheltered spaces. However, the genus is ecologically diverse and includes small litter dwellers with relatively short legs, rock- and ground dwellers with oval abdomens, and pale leaf-dwellers with worm-shaped abdomens.

In a first effort to structure the known diversity of Pholcus  , the genus was divided into 29 operational species groups ( Huber 2011a), including 25 species groups in the 'core group’, i.e., in ‘true’ Pholcus  . Even though the aim was to identify monophyla, some groups were explicitly proposed as 'waste baskets groups’ (e.g., the bamboutos group) or as "probably not monophyletic" (e.g., the circularis group). The present analysis clarifies a number of relationships, it supports several of the species groups and rejects others, and it confirms the non-monophyly of some groups as suspected. However, we acknowledge that internal relationships in Pholcus  remain highly uncertain and need considerably more work. Our data seem to suffer from two main problems that result in variable topologies among different types of analyses: (1) Even though Pholcus  is in our analyses represented by more species than any other genus (59), our sample is still highly incomplete, including only 18% of the described species and entirely missing seven of the previously suggested species groups (alticeps, nenjukovi, ponticus, zham, yichengicus, taishan, and nagasakiensis groups). (2) The percentage of missing sequences is high in Pholcus  , partly due to the fact that we identified paralogs for 28S and 18S that we excluded, partly due to other unidentified problems.

Of the 25 operational species groups within ‘true’ Pholcus  proposed previously ( Huber 2011a), ten are supported by the present data: phungiformes group, bidentatus group, calligaster group, Macaronesian group, gracillimus group (excl. P. mentawir  ), bicornutus  group, chappuisi group, lamperti group, debilis group (incl. P. nkoetye  Huber, 2011 and P. kribi  Huber, 2011), and guineensis group. Four groups are represented by single species (taarab group, ancoralis group, phalangioides  group, kingi group). Seven groups are missing in the analyses (see above). For the remaining four groups, the present analyses reject the monophyly: (1) The bamboutos group is polyphyletic as expected and the six species in our analyses split into four parts; of these P. kribi  is moved to the debilis group; P. bamboutos  Huber, 2011 is close to the guineensis group; the affinities of the other four species are unclear. (2) The circularis group is represented by three species; of these, P. nkoetye  is moved to the debilis group; P. leruthi  Lessert, 1935 and P. rawiriae  Huber, 2014 are sister species and close to the guineensis group. (3/4) The opilionoides  and crypticolens groups are both rejected, but together with the North American kingi group they form a monophylum with reasonable to high support (except for the 4+ genes analysis) but with unknown affinities with other groups.

The present analysis identifies two major clades within ‘true’ Pholcus  that are remarkable even though support values are low to modest. (1) A clade combining the ancoralis, gracillimus, and bicornutus  groups is composed of large dark Southeast Asian and Australasian species; a close relationship between the ancoralis group and the bicornutus  group has been suspected before, based on male ocular area modifications ( Huber 2011a: 314). (2) A large clade including all Subsaharan African taxa. This clade has low bootstrap support but SH values range from 81 to 96, so we consider this a first tentative indication that tropical African Pholcus  might form a large monophylum. The two species that disrupt this picture were both identified as rogue taxa: P. taarab  Huber, 2011 (which is not included in the clade but is African), and P. phalangioides  (which is included but is most probably not originally African). On the other hand, the inclusion of the Sri Lankan genus Sihala  Huber, 2011 in this clade is plausible, even though weakly supported. Our data highly support the inclusion of Sihala  in ‘true’ Pholcus  , but neither morphology nor molecules seem to give an indication about its sister taxon.

Notes on genera not included in the present analyses

Aucana  Huber, 2000. This Chilean genus (four species; formally including the mysterious New Caledonian A. kaala  Huber, 2000) was previously thought to be a member of Ninetinae  ( Huber 2000, 2011b). However, the procursus (dorsal apophysis and corresponding ventral pocket) suggests a placement in Arteminae  . Within Arteminae  , it shares an exposed tarsal organ with Chisosa  and Nita  ( Huber 2000, 2011b).

Blancoa  Huber, 2000. A small Venezuelan genus (two species), probably member of Modisiminae  ( Huber 2000), but the sister group remains entirely obscure.

Canaima  Huber, 2000. Also probably member of Modisiminae  , with only two species restricted to Trinidad and Venezuela ( Huber 2000). The shape of the ventral apo physis on the male palpal femur is reminiscent of the Venezuelan clade including Mecolaesthus  , Stenosfemuraia  , Systenita  , and ‘true’ Coryssocnemis  .

Cenemus  Saaristo, 2001. A small Seychellois genus (three species), member of Smeringopinae  ; a morphological cladistic analysis ( Huber 2012) suggested a placement in the 'northern clade’ of Smeringopinae  even though the Seychelles are geographically much closer to the 'southern clade’.

Enetea  Huber, 2000. A monotypic Bolivian genus, member of Ninetinae  ( Huber 2000); the sister group remains entirely obscure.

Galapa  Huber, 2000. A small genus (two species) restricted to the Galapagos Islands, member of Ninetinae  ( Huber 2000); the sister group remains entirely obscure.

Ossinissa  Dimitrov & Ribera, 2005. A monotypic genus from the Canary Islands, member of the Pholcus  group of genera ( Huber 2011a); the sister group is dubious, but we suspect a close relationship with other Canary Island cavernicole species in ‘true’ Pholcus  ( P. baldiosensis  Wunderlich, 1992; P. corniger  Dimitrov & Ribera, 2006).

Pomboa  Huber, 2000. Member of Modisiminae  , with currently four species restricted to Colombia. The vertical hairs in high density on the leg tibiae suggest an affinity to Pisaboa  and Waunana  ( Huber 2000).

Queliceria  González-Sponga, 2003. A monotypic Venezuelan genus, probably member of Modisiminae  ; the sister group remains entirely obscure.

Tibetia  Zhang, Zhu & Song, 2006. A monotypic Chinese (Tibetan) genus, probably member of Arteminae  ; the sister group remains entirely obscure.

Tolteca  Huber, 2000. A small Mexican genus (two species), member of Ninetinae  . We predict that Tolteca  is member of the North and Central American & Caribbean clade (Figure 2), together with Pholcophora  and Papiamenta  . The frontal humps on the male sternum and the shape of the procursus are reminiscent of Pholcophora  ( Huber 2000).