Pholcid spiders from the Lower Guinean region of Central Africa: an overview, with descriptions of seven new species (Araneae, Pholcidae)

This paper summarizes current knowledge about Central African pholcids. Central Africa is here defined as the area between 10°N and 7°S and between 6°E and 18°E, including mainly the Lower Guinean subregion of the Guineo-Congolian center of endemism. This includes all of Gabon, equatorial Guinea, São Tomé and Príncipe, most of Cameroon and Congo republic, and parts of the neighboring countries. An annotated list of the 14 genera and 79 species recorded from this area is given, together with distribution maps and an identification key to genera. Seven species are newly described: Anansus kamwai sp. nov., Leptopholcus gabonicus sp. nov., Ninetis faro sp. nov., Pholcus punu sp. nov., P. rawiriae sp. nov., Spermophora abibae sp. nov., and S. awalai sp. nov. Additional new records are given for 16 previously described species, including 17 new country records. Distribution and diversity patterns are compared with data on West and east Africa. While West Africa contains a similar set of genera it is significantly less diverse than Central Africa. East Africa is taxonomically more distinct. It has similar levels of diversity as Central Africa, but appears to be less undersampled.


Introduction
Central Africa is home to the world's second largest moist tropical forests, exceeded in area only by the Amazon Basin forests.In contrast to West and east Africa, where only about 10% of the original tropical moist forests remain (Naughton-Treves & Weber 2001; Norris et al. 2010), Central African forests may still extend over about half the original area (59.3% in 1992; Naughton-Treves & Weber 2001).While a high diversity of organisms otherwise concentrated in the tropics is thus expected for Central Africa, available data often fail to reflect this, probably for lack of exploration.Even relatively well-studied groups such as mammals, birds, and amphibians are poorly studied in parts of Africa, in particular in Central Africa (Dowsett-Lemaire & Dowsett 2001; Grubb 2001; Lawson & Klemens 2001), where cryptic diversity is probably more frequent than previously thought (Voelker et al. 2013).

HUBER B.A. et al., Central African pholcid spiders
material by about two to three orders of magnitude.revisions of all major and most minor pholcid genera present in Africa have more than tripled the number of described African species (Huber 2003a(Huber , b, c, 2007(Huber , 2009(Huber , 2011b(Huber , 2012(Huber , 2013)).Even though percentages of new species collected during intensive sampling trips suggest hundreds of undescribed species in tropical Africa (Huber in press), African pholcids can probably be considered fairly well known at the generic level.At least a framework is now available that roughly circumscribes each group in terms of morphology, distribution, and relationships, and that allows old species to be identified and new species to be recognized as such.
Two recent overviews of the Pholcidae from east Africa and West Africa have summarized the available information for each of these regions, including descriptions for species that had not been included in taxonomic revisions (Huber & Warui 2012;Huber & Kwapong 2013).The present paper is the last in this trilogy, concentrating of the third part of mainland tropical Africa that has received intensive recent attention both by collectors and in taxonomic revisions.

Material and methods
A large part of the material studied herein was collected during expeditions to Cameroon (2009) and Gabon (2011).This material is currently deposited at the Zoologisches Forschungsmuseum Alexander Koenig, Bonn (ZFMK).Further material was borrowed from the following institutions: Natural History Museum, London (BMNH); California Academy of Sciences, San Francisco (CAS); Musée royal de Format, style of descriptions, and terminology are as in recent revisions (e.g., Huber 2011bHuber , 2012Huber , 2013)).Measurements are in mm unless otherwise noted.The precision for eye measurements is ca. 5 µm.epigyna were cleared in a warm NaOH solution and stained with chlorazol black.Locality coordinates are in round brackets when copied from labels and original publications or when received directly from collectors, in square brackets when originating from some other source (such as online gazetteers, Google Earth, MRAC database, etc.).
The following abbreviations are used: ALE = anterior lateral eyes ALS = anterior lateral spinnerets AME = anterior median eyes a.s.l.= above sea level L/d = length/diameter PME = posterior median eyes The geographic area considered here (between 10°N and 7°S; between 6°E and 18°E; Fig. 19) encompasses mainly the Lower Guinean subregion of the Guineo-Congolian center of endemism (White 2001).The western and eastern limits of this subregion are somewhat controversial.In the west, the main current gap (Dahomey Gap; ~0-3°E) is not always congruent with distribution limits of taxa, which in many cases are further east (

Annotated list of Central African genera and species
Pholcidae described from Central Africa as defined herein, with countries, references, and new records.

Modisimus Simon, 1893
Of this otherwise New World genus, only the pantropical M. culicinus (Simon, 1893) occurs in Africa.It is probably common throughout the region, but rare in collections due to its small size and cryptic lifestyle.(Simon, 1893).Newly recorded for Central Africa [Fig.24; Lessert's (1938) record -sub Hedypsilus lawrencei -from Kananga, Congo D.R., is outside the area considered here].Ninetis Simon, 1890 This only African (and probably only Old World) genus of the subfamily Ninetinae is widely distributed from Namibia to the Arabian Peninsula, including Madagascar (Huber 2000(Huber , 2002;;Huber & El Hennawy 2007).The new species described below is the first representative of the genus (and subfamily) recorded from Central Africa (Fig. 25).

Note
The CAS has a single female specimen from Bioko (Pico Basilé) that may represent an additional (undescribed) species within the debilis group sensu Huber (2011b).Smeringopina Kraus, 1957 The Guineo-Congolian genus Smeringopina has its highest diversity in Central Africa (Huber 2013).Any Central African forest seems to contain one to three representatives of the genus, and places without known records have most probably never been searched adequately (Fig. 32).Of the 44 currently known species, 37 occur in the area considered here.except for S. fon Huber, 2013 (which ranges into West Africa) all of them are endemic to Central Africa.(Thorell, 1899).Cameroon (Thorell 1899; Huber 2013).(Thorell, 1899).Cameroon (Thorell 1899; Huber 2013).

Note
The new specimens are tentatively assigned to this species because the palps appear identical and the clypeus apophyses are at most minimally different (Figs 95-96).There is some slight difference in the color pattern but this has also been found among different populations in Ghana (

Identification key to Central African pholcid genera
References to figures in upper case ("Fig.") refer to illustrations herein; figures in lower case ("fig.") have been published previously and are freely accessible online (at http://www.pholcidae.de/).Artema atlanta Walckenaer, 1837 is included as it probably occurs in Central Africa, even though we know of no records.

Type locality
CAMerOON, Northwest Region, near Bamenda, under trash and logs at roadside (6°00.5'N,10°18.Color.Carapace ochre-yellow with irregular internal black pigment, sternum light brown with median dark line and four pairs of posteriorly diverging lines (Fig. 36); legs ochre-yellow without distinct dark rings; abdomen ochre-gray, with distinct dark heart-mark and thin dark line above spinnerets, dorsally with some white internal spots.
Body.Habitus as in Fig. 35; ocular area not elevated; carapace without median furrow; clypeus with rounded median process at rim (Fig. 42); sternum wider than long (0.48/0.36), unmodified.Chelicerae as in Fig. 42, with pair of lateral processes proximally and pair of pointed distal frontal apophyses without modified hairs; without stridulatory ridges.

Female
In general similar to male but clypeus unmodified; one female with darker chelicerae, clypeus, and sternum; tibia 1: 1.63 (missing in second female).Epigynum simple wide plate with pair of tiny pockets close together near posterior rim (Fig. 39), internal structures visible through cuticle; internal genitalia as in Fig. 43.

Distribution
Known from type locality in Cameroon only (Fig. 20).A poorly preserved male specimen from eastern Cameroon (Mbam near Koupoupi, MRAC 167.984) may also belong to this species.) by absence of clypeus modification in male (Fig. 45).

Etymology
Named for the country of Gabon, where this species is endemic.
Body.Habitus as in Fig. 44; ocular area not elevated, each triad on low hump; carapace without median furrow; clypeus unmodified; sternum wider than long (0.64/0.46), unmodified.Chelicerae as in Fig. 51, with pair of small lateral processes barely visible in dissecting microscope; without stridulatory ridges.
PalPs.As in Figs 46-47 and 49-50, coxa unmodified, trochanter with ventral apophysis with serrated tip, femur with large ventral hump and small retrolateral process proximally, procursus rather simple, with two membranous ventral processes, one arising from ventral 'knee', the other more distally; bulb with weakly sclerotized embolus, rod-shaped appendix with small scales, uncus consisting of sclerotized part with small scales and lighter dorsal flap.legs.Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 3%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 pseudosegments not seen.

Natural history
All specimens were found on the undersides of leaves.

Distribution
Known from various localities in Gabon (Fig. 22).

Etymology
The name is a noun in apposition, derived from the type locality.

Female
In general similar to male but clypeus, sternum, and chelicerae unmodified; tibia 1 in 5 females: 0.50-0.60(mean 0.53).Epigynum simple oval sclerotized area consisting of large anterior and smaller posterior plate; internal structures poorly visible through cuticle (Fig. 57); unclear if complex internal structures are part of anterior plate (as appears in dorsal view; Fig. 62) or posterior plate (as appears in ventral view); anterior plate with transversal ridge apparently connected to median pocket.Pore plates not seen (Fig. 62).

Distribution
Known from two localities in the North Region of Cameroon (Fig. 25).

Etymology
Named for the Punu (or Bapunu, Bapounou), one of the four major peoples of Gabon; noun in apposition.
Color.Carapace ochre-orange with large brown median mark, ocular area also brown, sternum medially slightly darkened; legs with dark rings on femora subdistally, patellae plus tibiae proximally, and tibiae subdistally; abdomen grey with internal black and whitish spots dorsally and laterally.
Body.Habitus as in Fig. 63; ocular area slightly elevated, each triad on short hump directed laterally; carapace without median furrow; clypeus unmodified; sternum wider than long (0.66/0.52), unmodified.Chelicerae as in Fig. 72, with pair of lateral processes proximally, pair of frontal apophyses proximally, and pair of frontal apophyses distally provided with two modified hairs each; without stridulatory ridges.
Variation.Tibia 1 in 22 other males: 6.7-8.8 (mean 7.9).Clypeus variably dark; AME spots sometimes fused.In most males the palps are extended and the bulbs rotated as in Fig. 71.

Natural history
The spiders were mostly found in the leaf litter and in cavities in the ground (Fig. 12), sometimes sharing the microhabitat with a representative of Smeringopina (e.g. S. moudouma Huber, 2013 in forest near Lastoursville; S. fang Huber, 2013 between Yéno and Mouila; S. lekoni Huber, 2013 at Lékoni River).The two specimens from Moudouma were found at the rock surface (Fig. 13) close to a small brook.

Distribution
Known from various localities in Gabon south of the Ogooué-Ivindo Rivers (Fig. 27; the closely related P. moca Huber, 2011 seems to be confined to the north of these rivers).

Diagnosis
Easily distinguished from known congeners by morphology of male palp (large trochanter apophysis; ventral femur apophyses; procursus with distal hinged sclerite strongly bent towards prolateral; bent embolus with spine-like processes; shape of appendix; Figs 80-81); from putative close relatives (bamboutos and circularis species groups) also by distinctive pattern on carapace (Fig. 75; transversal band on carapace; compare with figs.892-918 in Huber 2011b), and by female external and internal genitalia (narrow sclerotized rim and distinctive shape of 'valve'; long pore plates; Figs 76, 83).

Other material examined
Body.Habitus as in Fig. 75; ocular area slightly elevated, each triad on short hump directed laterally; carapace without median furrow; clypeus unmodified; sternum wider than long (0.92/0.70), unmodified.Chelicerae as in Fig. 82, with pair of small lateral processes proximally, directed slightly towards posterior, pair of low frontal humps, and pair of distal frontal apophyses provided with two modified hairs each; without stridulatory ridges.PalPs.As in Figs 77-81, coxa unmodified, trochanter with very large ventral apophysis, weakly sclerotized and distally curved towards prolateral, femur with one small and one larger distinctive ventral projection, procursus with distinctive hinged process distally strongly curved towards prolateral; bulb with long proximal sclerite, strongly bent embolus provided with several spine-like processes and distal fringes, without uncus, appendix with weakly sclerotized basal process.legs.Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 4%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 with >20 pseudosegments, only distally fairly distinct.
Variation.Not seen.Tibiae 1 missing in other males.

Natural history
Most specimens were found at tree trunks, with their bodies and legs tightly pressed against the bark and thus barely visible (Figs 14-15).

Distribution
Known from three localities in northern Gabon (Fig. 28).Huber,

Etymology
The species name commemorates the 11-year old girl, who was purchased for six handkerchiefs by James Jameson, a member of Henry Stanley's emin Pasha relief expedition, who gave her to cannibals so he could watch her being killed, cooked and eaten.Her name is not known.Abiba is an African name, meaning beloved.

Female
In general similar to male but sternum in most females dark brown or black (Fig. 90), clypeus unmodified, carapace with small median process acting against indistinct sclerotized plate above pedicel.Tibia 1 in 30 females: 3.7-4.9(mean 4.3).Epigynum simple rectangular plate, anteriorly with dark transversal internal structure, without pockets (Fig. 91); internal genitalia as in Fig. 93.

Relationships
Judging from the very similar morphology (including the most probably derived median process on the female carapace), this species is probably closely related to S. dieke from Guinea and the Guineo-Congolian S. akwamu.

Distribution
Known from type locality in Congo D.R. only (Fig. 34).Huber,    Color.Carapace ochre-yellow with black lateral margins and light brown median mark (Fig. 97), ocular area with dark band between eye triads, clypeus with a few black spots, sternum whitish, legs ochreyellow, with black spots on femora proximally, black patellae and tibia-metatarsus joints, dark rings subdistally on femora and tibiae (unusually far from tip), abdomen ochre gray with black marks dorsally and laterally.

Spermophora awalai
Body.Habitus as in Fig. 97; ocular area barely elevated, each triad on low hump; carapace without median furrow; clypeus unmodified; sternum wider than long (0.58/0.42), unmodified.Chelicerae as in Figs 104-105, with pair of proximal lateral apophyses and long frontal apophyses provided with three modified hairs each at tips, without stridulatory ridges.

Female
In general similar to male; tibia 1 in 10 females: 3.6-4.6(mean 4.2).Epigynum light brown area with pair of distinctive internal structures with concentric rings visible through cuticle (Figs 98, 106), with median pocket between epigynum and spinnerets; internal genitalia as in Figs 99 and 107.

Distribution
Known from several localities in Southwest and Centre Regions, Cameroon (Fig. 34).

Discussion
Distribution patterns except for some synanthropic and widespread species, the large majority of Central African Pholcidae are highly endemic.Considering just the two neighboring countries that were relatively well sampled (Cameroon and Gabon), the number of endemic species is considerably higher than the number of nonendemic species in each country.In Cameroon, 21 of the 35 currently recorded species (i.e.60%) are not known from any other country, not even neighboring Gabon.The numbers for Gabon are almost identical (21 of 33 species endemic, i.e. 64%).Diversity and endemism are especially high in the genus Smeringopina, with 13 of the 14 Cameroonian species and all 18 Gabonese species known from only Cameroon and Gabon, respectively.
Most of the species listed above (62, i.e. 84% if the five synanthropic species are discounted from the total number of 79) are endemics of the Lower Guinean subregion of the Guineo-Congolian center of endemism.Similar percentages of endemics have been found in West Africa (68%; value differs from that in Huber & Kwapong 2013 because Anansus atewa is no longer considered an endemic of West Africa) and East Africa (84%; calculated from data in Huber & Warui 2012).This is reflected in the fact that few species (again, discounting synanthropics) are shared among these regions.Only three species occur in all three regions:  Kraus, 1957), the latter reaching the western limits of East Africa (Huber 2011b(Huber , 2012)).
A comparison of the genera represented by endemic species in each of the three regions studied (Fig. 108) reveals significant differences between East and Central Africa but smaller differences between Central and West Africa.This is mainly due to the species-rich genera Buitinga Huber, 2003 and Smeringopina Kraus, 1957, the first being endemic to East Africa, the second to West and Central Africa.By contrast, the percentages of endemic species of Pholcus Walckenaer, 1805 are relatively homogeneous across tropical Africa.This is noteworthy because Pholcus has no endemic species in southern Africa or on Madagascar (Huber 2011b).

Diversity patterns
From a simple comparison of total species numbers, pholcid diversities in Central and east Africa appear to be similar (79 and 86 species respectively), while West Africa seems to be significantly less diverse (38 species; Fig. 109).This is not simply a result of different surface areas considered in each case.The land area of West Africa considered in Huber & Kwapong (2013; ~2.3 x 10 6 km 2 ) was actually larger than that of East Africa in Huber & Warui (2012; ~2.1 x 10 6 km 2 ) and that of Central Africa considered herein (~1.6 x 10 6 km 2 ).On the other hand, there is some evidence that the total numbers are biased against Central Africa because it seems most poorly collected.Figure 110 shows species numbers collected by the first author during expeditions of very similar durations and with very similar collecting efforts (West Africa: Guinea, Ghana; Central Africa: Cameroon, Gabon; East Africa: Kenya, Uganda).The much higher number of new species found in Central Africa suggests that this region is in fact undersampled relative to West and east Africa.recent evidence on forest-dwelling insects suggests that the diversity is higher in Central Africa (and in particular in Cameroon) than in any other part of Africa (P.Le Gall, unpublished).
Diversity is also high at individual localities (with 'locality' roughly defined as the area that can be covered in one day by walking).Few localities worldwide are known to contain more than 10 species of Pholcidae each, most of them in Brazil's Atlantic Forest (Huber & Rheims 2011; B.A. Huber, unpublished data).Luki Forest Reserve in Central Africa is currently the most diverse locality in Africa for this family.Eleven of its 13 known species (the last of which is described herein), have been described within the last decade: Anansus debakkeri Huber, 2007; Leptopholcus debakkeri Huber, 2011; L. tipula (Simon, 1907) Huber, 2007.Since Luki Forest reserve is probably among the best sampled African localities as far as spiders are concerned (as a result of two major campaigns by MRAC focusing on this single forest), it is likely that increased effort will reveal more such diverse localities in Central Africa.The fact that 10 species were collected at Mayebout (Gabon) within two days by only two collectors (one of them inexperienced) also points in that direction.

Outlook
Two recent expeditions to Cameroon and Gabon resulted in a total of 54 pholcid species, 42 of which (78%) were still undescribed a decade ago.All this material and most of the Central African material deposited in other major arachnological collections is now described.However, the high percentage of undescribed species collected during about seven weeks in the field also illustrates the relative ease with which new pholcid species can still be discovered in this region.This is probably a general pattern, as suggested by recent studies on arthropods in lowland forests in Cameroon (e.g., Larsen 2005) and on   2007).Species distribution patterns also suggest that even in areas relatively well sampled (western Cameroon, Gabon, western Congo D.R.), many undiscovered species may remain.Of the 79 Central African species listed above, 33 (42%) are known from their type localities only.Denser sampling across seasons and altitudes will probably reveal not only more realistic distribution patterns, but also additional new species even in these areas.
On the other hand, large areas within Lower Guinea remain almost entirely unexplored with respect to spiders and to Pholcidae in particular (Fig. 19).Congo Republic is among the few countries worldwide from which the first author has never seen even a single pholcid specimen.Only a single (doubtful) record seems to exist in the literature (a juvenile Smeringopus pallidus cited in Lawrence 1958).With large parts of its moist tropical forests remaining (over 60% as of 1992; Naughton-Treves & Weber 2001), Congo Republic is likely to have similar numbers of species as neighboring Gabon (currently 33).The same is true for large parts of southeastern Cameroon, eastern Nigeria, and southwestern Central African Republic (Fig. 19).
Cross River Basin of eastern Nigeria, ~8°E) (Dowsett-Lemaire & Dowsett 2001; Lawson & Klemens 2001; Maley 2001).In the east, both the Gabon-Congo watershed and the Sangha-Ubangui Rivers have been proposed as limits (Dowsett-Lemaire & Dowsett 2001).For the present overview, however, the exact western and eastern limits are fairly irrelevant since the pholcid faunas of Nigeria and Congo republic remain largely unknown.The southern and northern limits were chosen to include western Congo D.R. (with the excellent collections from Luki Forest Reserve in MRAC) and all known pholcid records from Cameroon (no record from beyond 10°N is known to us).

Figs 27 - 28 .
Figs 27-28.Known distributions of the bamboutos and circularis species groups (sensu Huber 2011b) of Pholcus Walckenaer, 1805 in Central Africa.The question mark denotes an undescribed species represented by a single male in uSNM.

Fig. 108 .
Fig. 108.Pholcid genera represented by endemic species (total numbers of endemic species in parentheses) in each region (West, Central, and East Africa), illustrating the distinctness of East Africa as compared to West and Central Africa.Data on East and West Africa from Huber & Warui (2012) and Huber & Kwapong (2013), respectively.White: genera that are not represented by more than four endemic species in any of the three regions.

Figs 109- 110 .
Figs 109-110.Pholcid species from West, Central, and East Africa, divided into 'old' species (grey; described before 2003) and 'new' species (green; described since 2003).109.Current totals as listed in Huber & Warui (2012), Huber & Kwapong (2013) and herein, suggesting lower diversity in West than in Central and east Africa.110.Species collected by the first author during six expeditions (two to each region) of very similar durations and with very similar collecting efforts, suggesting that Central Africa may be more severely undersampled than West and east Africa.

; only P. baka ranges into Congolia). While the monophyly of the debilis group is well supported, the relationships within and among the other groups remain largely obscure
(Huber 2011b;Dimitrov et al. 2013).
DiagnosisDistinguished from P. moca Huber, 2011 (the most similar species and probably closest known relative) by shape of procursus (longer retrolateral process; absence of distinct ridge between retrolateral process and tip; compare Fig.70with fig.946 in Huber 2011b); also by shape of uncus (not bilobed as in European Journal of Taxonomy 81: 1-46 (2014) P