PHOLCIDAE KOCH, 1851

HUBER, BERNHARD A., 2000, New World Pholcid Spiders (Araneae: Pholcidae): A Revision At Generic Level, Bulletin of the American Museum of Natural History 2000 (254), pp. 1-348 : 41-53

PHOLCIDAE KOCH, 1851 (Synonymies: Bonnet, 1958: 3602)

DIAGNOSIS

Pholcids are small to medium-sized spiders (~ 1–15 mm body length), with a prosoma that is about as long as wide, but oth- erwise they are extremely variable in habitus. They are easily distinguished from other families (both from the putative sister taxon Diguetidae + Plectreuridae , and from generally similar spiders like Ochyroceratidae , Filistatidae , etc.) by the following characters: (1) Male palp with prominent retrola- teral paracymbium (procursus) which is very rarely reduced to an inconspicuous lobe (figs. 466, 475). (2) Male chelicerae with sexual modifications, which are rarely absent. (3) Clypeus about as high as chelicerae are long. (4) Tarsi pseudosegmented; in some genera the pseudosegments are hardly visible under light microscopy, and seem secondarily fragmented into smaller sclerites (figs. 97–101). (5) The number of trichobothria on the tibiae of walking legs is reduced to three; rarely an individual has one or more legs with only two trichobothria on the tibiae.

DESCRIPTION

Small to medium-sized, ecribellate, haplogyne spiders. Total length 1–15 mm, but usually less than 10 mm. Usually with eight or six eyes, rarely with two; cave species often blind. Eye pattern varies widely (e.g., figs. 1–11); most common and possibly plesiomorphic condition characterized by two lateral triads and median anterior pair (e.g., figs. 3–5). Six-eyed species lack AME. In some genera eyes sit on conspicuous elevations, either on median turret or on lateral eye-stalks (figs. 7–9). Carapace about as wide as long, either without median indentation, or with median groove, or with median circular depression (pit); in some species male prosoma conspicuously inflated posteriorly (e.g., figs. 1024, 1060, 1069). Clypeus ranging from almost vertical to almost horizontal, sometimes sexually modified in male (e.g., figs. 2, 273, 1213). These modifications may be ultrastructurally complex (fig. 107). Sternum about as wide as long, or wider than long, sometimes with anterior bulges in male (e.g., figs. 318, 450, 1104). Labium fused to sternum.

Opisthosoma extremely variable in shape, from higher-than-long to long-cylindrical; spherical, triangular (in lateral view), rectangular, or bifid (in dorsal view). With one pair of book-lungs. Tracheal system rudimentary or absent. Male gonopore usually with either four epiandrous spigots (figs. 113–118, 120–129) or without (figs 130– 141), rarely with two (fig. 119) or up to six (e.g., in Crossopriza lyoni ; see Huber et al., 1999). Female external genitalia with or without sclerotized plate (‘‘epigynum’’). This plate is often complex, with pockets, grooves, apophyses, etc. Internally, uterus externus usually provided with pair of dorsal pore plates (rarely absent, or fused into single pore plate or dissolved into pore field), and valve of varying complexity marking entrance to uterus internus (Huber, 1998d). Membranous sacs originating from uterus externus close to valve are common (usually single median sac, rarely lateral pair), but their function is unknown. Three pairs of spinnerets present (figs. 142–145), apparently no sexual dimorphism concerning external morphology: ALS always equipped with enlarged and widened spigot and smaller, point- ed spigot next to it. (For current terminology see Platnick et al., 1991.) In addition to this basic set, some large taxa characterized by presence of about five to seven roughly cylindrical spigots (figs. 146–169), here called piriform gland spigots in accordance with Platnick et al. (1991). Other taxa have only basic set of two spigots (figs. 170–190). Posterior median spinnerets equipped with one pair of spigots in all species studied (figs. 191–199), posterior lateral spinnerets lack spigots. Various types of stridulatory organs exist that involve parts of prosoma and opisthosoma (the term stridulation may actually be inappropriate in some or all of these cases), present only in females: paired and unpaired dorsal protrusions of carapace acting against modified fields on opisthosoma [e.g., Physocyclus spp. (Huber, 1998e) ; Crossopriza lyoni (Huber et al., 1999) ; ‘‘ Coryssocnemis ’’ viridescens (Huber, 1998a) ; Anopsicus spp. (Gertsch, 1982) ; Aymaria spp. ; see p. 155]; in one case, median grate on sternum acting against transverse row of cuspules on opisthosoma (fig. 1114).

Chelicerae fused at basis, with lamina (never teeth) opposing cheliceral fang. Basal segment almost always sexually modified in male, with modifications ranging from variously shaped hairs (figs. 12–15, 18–24) and simple sclerotized cones to extravagantly shaped apophyses and depressions; rarely also fangs modified in male (figs. 30–32, 620, 631). Stridulatory files (figs. 36, 38, 40) common, but in New World restricted to some ninetine genera, to Physocyclus , and very few species of Metagonia . Stridulatory pick apparently always one or more modified hairs proximally on palpal femur (figs. 37, 39, 41). Same type of stridulation also common in females.

Male palp with sexual modifications involving most or all segments. Coxa often with retrolateral apophysis (e.g., figs. 583, 1096, 1075). Prolateral (inner) side of coxa may be quite complex (figs. 111–112), but has not been studied comparatively. Trochanter sometimes with long ventral apophysis (e.g., fig. 299) that may be equipped distally with strange modified hair (figs. 105–106), or with fingerlike protrusion (e.g., figs. 658, 688). Femur very variable in shape, from cylindrical to globose, often widened distally; with one or more apophyses of various shapes, usually proximally on retrolateral side and ventrally. Patella cylindrical, or reduced ventrally, or (in single monotypic genus) completely absent (figs. 390–392). Tibia cylindrical, spindle-shaped, or globose, always with two trichobothria (dorsally and retrolaterally). Cymbium with usually large paracymbium (procursus); procursus usually as long as or longer than femur, often quite complex; in some genera provided with filiform projections (figs. 48–51); in only one genus reduced to simple short lobe (figs. 466, 475). Ultrastructural complexity little studied, but evidently common (e.g., figs. 42– 47). Tarsal organ either exposed (figs. 79– 95) or capsulate (figs. 61–78), with variable relative width of opening, or (in Priscula only) sitting on stalk (fig. 96). Bulb usually attached to prolateral side of cymbium (rarely to dorsal side), either with membranous tubular embolus or without embolus. In latter case, sperm duct opens at or near basis of some bulbal apophysis, or travels variable distance into ‘‘embolar division,’’ a projection of bulb very unlike ‘‘real’’ (narrow and cylindrical) embolus (e.g., figs. 52, 54–55). Sclerotized bulbal apophyses present in some taxa. Ultrastructural complexity common (e.g., figs. 52–60), but little studied.

Legs of variable relative length (male leg 1 about 2–25 X body length), but usually relatively long. ‘‘Robustness’’ of legs, as measured by ratio of male tibia 1 length/diameter equally variable (range ~ 8–120), with values of 40 –100 most commonly found. Females always have shorter and more slender legs. Male femora 2 and 3 sometimes comparatively thicker than others. Leg formula most commonly 1243, but in short-legged taxa usually 4123, sometimes 1423. Spines (macrotrichia: figs. 110, 823, 910) and long, backward-curved hairs may be present on femora, tibiae, and metatarsi, but spines rare in females. Short hairs in roughly vertical position always present in low numbers on most segments in both sexes, especially distally, but in males of some taxa such hairs occur in very high densities (cf. figs. 108–109), either on femur or on tibia, rarely on both. Trichobothria present on tibiae (almost always three; rarely some specimens have one or more tibiae with only two), and metatarsi (always one). Dorsal and prolateral trichobothria on tibiae always situated quite proximally, while position of retrolateral trichobothrium varies widely. Its position expressed as percentage of tibia length ranges from ~ 1–70%, with very little intraspecific variation. Trochanter provided retrolaterally with cuneal notch (Roth, 1964) in all species seen by author. Tarsi always pseudosegmented, with ~ 5 to over 40 pseudosegments, usually distinct distally but difficult to count proximally. In soma taxa pseudosegmentation hardly visible in light microscopy, and SEM reveals secondary fragmentation into smaller sclerites (figs. 97– 101). Tarsal organs on legs not different from those on palps in few species checked. All tarsi with three claws (figs. 102–104).

NATURAL HISTORY

Pholcids are probably among the commonest web-builders in the Neotropics, as suggested by the few scattered studies that provide data relevant to this question (see Introduction). They are found from sea level to over 3500 m in the Andes (e.g., Chibchea abiseo , n. gen., n. sp.), with high diversity apparently not restricted to the lower elevations. They are found in most life zones, from rain forests to deserts (e.g., Chile: Atacama Desert), though it is, of course, the zones of highest general biodiversity that house the greatest abundance of pholcid species. Finally, with respect to the microhabitat, pholcids are found in almost all habitats feasible for spiders, from the leaf litter and undersides of stones up to the tree canopies. Here the area of highest diversity suspiciously coincides with the level most easily accessible to humans, i.e., the shady areas near the ground and between buttresses, and the low vegetation. In some areas there is evidence that pholcids are not just well represented, but are the dominant spider group: 62% of spiders collected from bark in a Peruvian forest were pholcids (Manhart, 1994). At the same time, pholcids are among the spiders most consistently found in caves, and several species of various genera are independently preadapted to live and spread with humans, as is evidenced by the numerous synanthropic species from various genera worldwide.

Most species seem to build webs, but in some cave- and ground-living pholcids the web is reduced to a flimsy sheet, and the spiders can quickly run over unspun surfaces. Web structure varies from three-dimensional irregular networks (Kirchner, 1986, on Pholcus phalangioides ) to more organized domed sheets with a tangle of lines above the sheet (Wiehle, 1933 on Holocnemus hispanicus ; Eberhard, 1992a, 1992b; Eberhard and Briceño, 1985, on New World species), which in rare cases may lead into a tubular retreat, analogous to for example, agelenids [Huber, 1998b, on Coryssocnemis (now Ixchela ) furcula ]. Some taxa are adapted to live on the undersides of leaves; here again, the web is reduced or absent. In the same way that many pholcids do not live up to their English vernacular name (‘‘daddy longlegs’’), many do injustice to their German name too (Zitterspinnen, i.e., ‘‘shaking spiders’’): instead of vibrating or swinging at a perceived danger, many short-legged species swiftly run away, while some leaf-dwellers prefer to press their bodies closely against the leaf.

While Old World species have been studied for a long time with respect to their sexual biology (Montgomery, 1903; Gerhardt, 1921, 1923, 1924, 1927, 1929; Huber, 1995; Uhl et al., 1995), there have only recently been accumulated some data on the sexual biology of New World pholcids, mainly of Central American genera (Eberhard and Briceño, 1983, 1985; Huber, 1994, 1997c, 1997d, 1998a, 1998c; Huber and Eberhard, 1997). The scarce information available on South American species is detailed in the species descriptions below ( Mesabolivar eberhardi , p. 201: Litoporus lopez , p. 299).

COMPOSITION

At the final revision of the manuscript (February 2000) I counted 720 extant nominal species in 63 extant genera worldwide (the monotypic genus Serratochorus Wunderlich and eight further species from two extant genera are only known from Dominican amber). In the New World, 457 extant species in 47 extant genera are described. Of these 47 genera, six are only represented by a single introduced species each ( Artema , Micropholcus , Crossopriza , Holocnemus , Smeringopus , Spermophora ); two are represented by several native species, but are clearly also Old World genera ( Pholcus , Leptopholcus ). This leaves a total of 39 endemic New World genera (see also appendix 4).

KEY TO THE EXTANT GENERA OF THE NEW WORLD

This key only works if both males and females are available. In some genera only males are necessary. Throughout, a dissecting microscope is sufficient, though some couplets (e.g., 5, 9) require high magnifications. It is obvious that at the present state of knowledge a key to genera can only be preliminary, and will have to be emended as new species (and probably genera) become known. Stenosfemuraia González-Sponga is not included because I have not seen this genus.

1. North and Central America, including Panama and Lesser Antilles, but without Trinidad and Tobago, and without Netherlands Antilles............ 2

– South America, including Netherlands Antilles, Trinidad and Tobago, and Galápagos Islands............... 23

2(1). Six eyes or fewer................ 3

– Eight eyes...................... 7

3(2). Six eyes on median eye turret (fig. 9)....................... Modisimus

– Six or fewer eyes not on elevated ocular area......................... 4

4(3). Procursus with ventral hinged process (figs. 208, 213, 276).... Metagonia

– Procursus without ventral hinged process ............................. 5

5(4). Male chelicera proximolaterally without apophysis; palpal femur ventrodistally with apophysis......... Anopsicus

– Male chelicerae proximolaterally with apophysis; palpal femur without ventrodistal apophysis.............. 6

6(5). Opisthosoma globular; synanthropic......... Spermophora ( senoculata )

– Opisthosoma long, cylindrical; only on Antilles............ Leptopholcus

7(2). Male palpal femur ventrodistally with apophysis (figs. 564, 1086, 1110).. 8

– Male palpal femur ventrodistally without apophysis.................... 12

8(7). Male and female femora with several rows of spines; only on Hispaniola......................... Tainonia

– Male and female femora without or with only one (ventral) row of spines in males........................ 9

9(8). Male femora with many short vertical hairs (figs. 108–109)........... 10

– Male femora without or very few short vertical hairs................. 11

10(9). Ocular area low; male tibiae with many short vertical hairs....... Waunana

– Ocular area high; male tibiae without or very few short vertical hairs........................... Modisimus

11(9). Opisthosoma globular; Mexico and USA.................... Psilochorus

– Opisthosoma longer than high; Lesser Antilles............ Mecoloesthus

12(7). Opisthosoma globular or higher than long............................ 13

– Opisthosoma longer than high..... 19

13(12). Male chelicerae with several to many cone-shaped, black projections... 14

– Male chelicerae with none to two pairs of cone-shaped black projections, or with longer apophyses.............. 15

14(13). Conical projections on male chelicerae are apophyses; male chelicerae usually (always?) with stridulatory ridges (fig. 578)................ Physocyclus

– Conical projections on male chelicerae are modified hairs (figs. 12–13); male chelicerae without stridulatory ridges; synanthropic...... Artema ( atlanta )

15(13). Large spiders (> 5 mm body length), with characteristic prolateroventral protrusion on genital bulb (see fig. 43 in Huber 1998b).......... Ixchela

– Small spiders (<3 mm body length).............................. 16

16(15). Male chelicerae proximolaterally with apophyses; procursus dorsally with movable process; synanthropic................ Micropholcus ( fauroti )

– Male chelicerae proximolaterally without apophysis; procursus dorsally without movable process.............. 17

17(16). Carapace without groove; male sternum without anterior humps; procursus voluminous (figs. 483, 490)... Chisosa

– Carapace with shallow but distinct median groove; male sternum with anterior humps; procursus simple.... 18

18(17). Male chelicerae with stridulatory ridges and one pair of large frontal apophyses proximally........... Pholcophora

– Male chelicerae without stridulatory ridges; with one pair of small frontal apophyses distally......... Tolteca

19(12). Carapace with roundish indentation (pit); male chelicerae without proximolateral apophysis; synanthropic, introduced Old World species............. 20

– Carapace without indentation; male chelicerae with proximolateral apophysis............................ 22

20(19). Opisthosoma pointed posterodorsally; two pairs of frontal apophyses on male chelicerae...... Crossopriza ( lyoni )

– Opisthosoma rounded posterodorsally; male chelicerae with one pair of frontal apophyses................... 21

21(20). Male femur with spines ventrally; male and female chelicerae with stridulatory ridges; female palp distally enlarged.............. Holocnemus ( pluchei )

– Male femur without spines ventrally; male and female chelicerae without stridulatory ridges; female palp not enlarged...... Smeringopus ( pallidus )

22(19). Only Antilles; pale..... Leptopholcus

– Only eastern USA; outside this area, only the dark-patterned, synanthropic P. phalangioides ............ Pholcus

23(1). Male chelicerae with single, medially fused apophysis (fig. 358)................... Ibotyporanga ( naideae )

– Male chelicerae otherwise........ 24

24(23). Procursus reduced to simple lobe (figs. 466, 475); only on Netherlands Antilles.................... Papiamenta

– Procursus well developed......... 25

25(24). Procursus extremely long, bandlike (figs. 1096–1097).............. Kaliana

– Procursus otherwise............. 26

26(25). Carapace without thoracic groove or pit ............................ 27

– Carapace with thoracic groove or pit... ............................ 35

27(26). Male chelicerae with proximolateral apophysis (only synanthropic Old World species)................ 28

– Male chelicerae without proximolateral apophysis.................... 29

28(27). Small spider (~ 2 mm body length) with globular opisthosoma........................ Micropholcus ( fauroti )

– Large spider (over 5 mm body length) with long opisthosoma..................... Pholcus ( phalangioides )

29(27). Six eyes; long legs; procursus usually with ventral hinged process (e.g., figs. 208, 213, 276)......... Metagonia

– Eight eyes; short legs; procursus without ventral hinged process......... 30

30(29). Male palp without patella (figs. 390–392)........................ Enetea

– Male palp with patella........... 31

31(30). Proximal segment of male chelicera unmodified; male fang with apophysis (fig. 384); only on Galápagos Islands ........................ Galapa

– Proximal segment of male chelicera with one or more apophyses; male fang without apophysis; not on Galápagos Islands ...................... 32

32(31). Procursus only half as long as bulb (fig. 339).................. Kambiwa

– Procursus as long as bulb......... 33

33(32). Male chelicerae with several (2–4) pairs of tiny cones frontally (figs. 400, 415); procursus simple.......... Aucana

– Male chelicerae with one pair of frontal apophyses................... 34

34(33). Cheliceral apophyses long, projecting forward (fig. 372); procursus with dorsal flap (figs. 374, 378, 380)............................ Guaranita

– Cheliceral apophyses short, projecting downward (fig. 333); procursus without dorsal flap........... Nerudia

35(26). Procursus wrapped around embolar division of bulb (fig. 1260)...... Teuia

– Procursus not wrapped around embolar division of bulb............... 36

36(35). Legs short (leg 1 <4.5 X body length) ............................ 37

– Legs longer (leg 1> 4.5 X body length; shorter only in some Chibchea species ) ............................ 38

37(36). Eight eyes; procursus long, S-shaped band, without hinged process (figs. 346, 353)........................................... Gertschiola

– Six eyes; procursus shorter, with hinged process (fig. 286)........................... Metagonia ( globulosa )

38(36). Carapace with thoracic pit........ 39

– Carapace with thoracic groove......43

39(38). Male chelicerae with several to many cone-shaped, black projections (only introduced, synanthropic species) 40

– Male chelicerae with one to two pairs of apophyses................... 41

40(39). Conical projections on male chelicerae are apophyses; male chelicerae with stridulatory ridges; female carapace with cone posteriorly....................... Physocyclus ( globosus )

– Conical projections on male chelicerae are modified hairs; male chelicerae without stridulatory ridges; female carapace without cone posteriorly..................... Artema ( atlanta )

41(39). Male palpal coxa with retrolateral apophysis (fig. 583); cheliceral apophyses without imbedded modified hairs........................... Aymaria

– Male palpal coxa without retrolateral apophysis; cheliceral apophyses with imbedded modified hairs (figs. 14–15);

introduced, synanthropic Old World species...................... 42

42(41). Opisthosoma pointed posterodorsally; two pairs of frontal apophyses on male chelicerae; male femur with spines ventrally; male and female chelicerae with stridulatory ridges......................... Crossopriza ( lyoni ) – Opisthosoma rounded posterodorsally; male chelicerae with single pair of frontal apophyses; male femur without spines ventrally; male and female chelicerae without stridulatory ridges.............. Smeringopus ( pallidus )

43(38). Large pholcid (body length> 3.5 mm) with high opisthosoma.... Priscula – Usually small; if large, then opisthosoma longer than high.............. 44

44(43). Male chelicerae frontally with black pectinate apophysis (fig. 1232)............................. Otavaloa – Male chelicerae frontally with several (~ 5–50) cone-shaped or globular hairs (figs. 18–20, 947, 967)... Carapoia – Male chelicerae otherwise........ 45

45(44). Male palpal patella ventrally as long, or almost as long as wide (figs. 1266, 1300, 1304)............. Tupigea – Male palpal patella ventrally very short............................ 46

46(45). Male femur 1> 1.15 X tibia 1; legs extremely long and thin.... Litoporus – Male femur 1 about as long as tibia 1.............................. 47

47(46). Procursus lying in groove of bulb; male chelicerae with pair of club-shaped hairs on each side (fig. 29 in Huber, 1997b)................. Systenita – Procursus not lying in groove of bulb; male chelicerae different........ 48

48(47). Male palpal tibia globular (figs. 1338, 1349).................. Blancoa – Male palpal tibia longer than wide.. 49

49(48). Epigynum with median groove or pocket (e.g., figs. 746, 808, 892)............................ Mesabolivar – Epigynum without median groove or pocket...................... 50

50(49). Male prosoma inflated posteriorly...................... Mecoloesthus – Male prosoma not inflated posteriorly.............................. 51

51(50). Male cheliceral fang with apophysis (figs. 620, 631, 666, 681)...... Chibchea – Male cheliceral fang unmodified... 52

52(51). Male femora of legs with many short vertical hairs; only western Colombia and Ecuador..................... 53

– Male femora of legs without or with very few short vertical hairs......... 54

53(52). Six eyes on high eye turret; male tibiae of legs without or with very few short vertical hairs.......... Modisimus – Eight eyes on moderately elevated ocular area; male tibiae of legs with many short vertical hairs....... Waunana

54(52). Male chelicera with articulated apophysis (figs. 16, 1140, 1148, 1155); procursus very long, overreaching palpal coxa....................... Pisaboa – Male chelicera without articulated apophysis; procursus not reaching palpal coxa........................ 55

55(54). Six eyes; chelicerae with short entapophyses (figs. 1321, 1330).. Canaima – Eight eyes; chelicerae with long entapophyses...................... 56

56(55). Male chelicerae with only one pair of apophyses............. Chibchea – Male chelicerae with three to several cone-shaped apophyses (figs. 987, 997, 1001, 1005)........ Coryssocnemis