Cenemus culiculus (Simon, 1898)

Huber, Bernhard A. & Meng, Guanliang, 2023, On the mysterious Seychellois endemic spider genus Cenemus (Araneae, Pholcidae), Arthropod Systematics & amp; Phylogeny 81, pp. 179-200 : 179

3.2.2. Cenemus culiculus (Simon, 1898)

Figs 5-11 , 12-17 , 18-20 , 21-23 , 24-28 , 29-37 , 38-46 , 47-54 , 55-63

Holocnemus culiculus Simon, 1898: 375 (juv.); Saaristo 1978: 103, figs 27-30, 39-45 (♂♀).

Cenemus culiculus (Simon, 1898); Saaristo 2001: 19, figs 36-41, 47-48; Saaristo 2010: 160, figs 25.6-15 (text and figures copied from previous papers, with errors, e.g. regarding material of C. mikehilli listed under C. culiculus ).

Diagnosis.

See Saaristo (2001, 2002) for morphological differences between the three nominal species. Interspecific relationships are beyond the scope of this study.

Type.

SEYCHELLES - Mahé • 1 juvenile holotype, examined; precise locality not identified; 1895; A. Brauer leg; MNHN 10343, with E. Simon’s handwritten label "15220 Hol. culicinus [sic!] ES, Ins. Sechelles (Brauer)" .

Material examined.

SEYCHELLES - Mahé • 1 ♂, 2 ♀♀; Anse Boileau, Glacis La Reserve ; 4.7070°S, 55.5007°E; 230 m a.s.l.; 7 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23864 • 1 ♂ in pure ethanol; same data as preceding; ZFMK Sey 25 • 1 ♂, 2 ♀♀; Bel Ombre, "site 2"; 4.6215°S, 55.3914°E; 80 m a.s.l.; 6 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23865 • 1 ♀ in pure ethanol; same data as preceding; ZFMK Sey 28 • 7 ♂♂, 6 ♀♀; Bel Ombre, "site 1"; 4.6215°S, 55.3957°E; 70 m a.s.l.; 6 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23866 • 2 ♀♀, 1 juv., in pure ethanol; same data as preceding; ZFMK Sey 24 • 1 ♂, 3 ♀♀; Port Glaud, Casse Dent ; 4.648°S, 55.428°E; 450 m a.s.l.; 8 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23867 • 1 ♀ in pure ethanol; same data as preceding; ZFMK Sey 27 • 7 ♂♂, 8 ♀♀; Port Glaud, Morne Blanc ; 4.6559°S, 55.4388°E; 430 m a.s.l.; 4 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23868 to 23869 • 2 ♀♀, 4 juvs, in pure ethanol; same data as preceding; ZFMK Sey 22 • 1 ♀; Port Glaud, near Cap Ternay ; 4.6452°S, 55.3883°E; 40 m a.s.l.; 4 Mar. 2013; C. Hoareau leg.; ZFMK Ar 23870 . - Silhouette • 1 ♂, 1 ♀, see Remarks below; Jardin Marron ; 4.48°S, 55.24°E; 20 Jan. 1999; M. Saaristo and J. Gerlach leg.; MZT (without number; presumably taken from MZT AA 1108 to 1110) .

Redescription.

Male (ZFMK Ar 23866) - MEASUREMENTS. Total length 6.5, carapace width 2.2. Distance PME-PME 100 µm; diameter PME 160 µm; distance PME-ALE 100 µm; diameter AME 110 µm; distance AME-AME 30 µm. Leg 1: 59.4 (14.7 + 0.9 + 14.5 + 25.7 + 3.6), tibia 2: 8.7, tibia 3: 6.2, tibia 4: 7.3; tibia 1 L/d: 55; femora 1-4 diameters at half length: 0.40, 0.31, 0.30, 0.30. - COLOR (in ethanol). Carapace pale ochre with median brown band including ocular area and pair of submarginal lateral bands (Fig. 5 ); clypeus light brown; sternum dark brown, with lighter brown median mark, narrow lateral light bands, and dark brown lateral margins; legs brown, femora and tibiae with light tips and dark brown to black subdistal rings; abdomen ochre-gray, with dark marks dorsally and laterally, ventrally with large black marks in front of gonopore and at spinnerets, with lighter brown diffuse median band behind gonopore. - BODY. Habitus as in Fig. 5 . Ocular area raised; each secondary eye with small accompanying elevation (Fig. 30 ). Carapace with short but deep thoracic pit dividing posteriorly into pair of diverging shallow furrows extending toward posterior margin (Fig. 29 ). Clypeus unmodified, only rim slightly more sclerotized than in female and median stripe with slightly different cuticle (as in female; cf. Fig. 48 ). Sternum wider than long (1.4/0.9), unmodified. Abdomen cylindrical, dorso-posteriorly rounded. Gonopore with six epiandrous spigots (Fig. 31 ; three males examined). ALS with one widened spigot and one pointed spigot (Fig. 32 ); PME with two conical spigots (Fig. 32 ). - CHELICERAE. As in Figs 12-13 ; with pair of frontal lateral apophyses, each with one modified cone-shaped hair (Figs 33-34 ); distance between tips of modified hairs: 0.74; without proximal protrusion; frontal face of chelicerae with numerous pores of unknown function (Fig. 35 ); lateral stridulatory files distinct (Fig. 36 ), ~70 ridges, distances between ridges proximally ~6 µm, distally ~4 µm. - PALPS. As is Figs 9-11 ; coxa with rounded retrolateral hump, prolaterally with complex system of comb-shaped processes and long and short hair-like processes (Fig. 37 ); trochanter barely modified; femur distally widened, with rounded ventral protrusion, dorsally straight, without proximal retrolateral process, with distinct retrolateral transversal line, with prolateral stridulatory pick proximally (Fig. 38 ); femur-patella joints shifted toward prolateral side; patella triangular in lateral view, i.e. very short ventrally; tibia large compared to femur, tibia-tarsus joints shifted toward retrolateral side; tarsus without macrotrichia, with short dorsal process carrying capsulate tarsal organ (Fig. 39 ); procursus (Figs 18-20 ) straight, without ventral “knee”, with dense brush of hairs dorsally and laterally (Fig. 42 ), proximally without prolateral hump but with ridge, procursus tip with bifid dorsal sclerite, prolateral tip short and sclerotized, retrolateral tip longer and semitransparent (Fig. 19 ), procursus tip retrolaterally with small projections around pit with four hair-shaped processes (Fig. 40 ), ventrally without (or with strongly reduced?) ventral spine; genital bulb (Figs 14-17 ) with ventral hump, simple basal sclerite connected to distal (main) sclerite; distal sclerite with two distinctive processes: short rounded retrolateral process and longer prolateral process bent at right angle (Figs 43-44 ), with two transparent processes originating from basis of prolateral process, possibly extensible and with complex tip (Figs 45-46 ); sperm duct opening at basis of long prolateral process (arrows in Figs 43-44 ). - LEGS. Without spines; without curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 2%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 with ~35 distinct pseudosegments (cf. female, Fig. 56 ); tarsal organs capsulate, distinctively oval, with indentation medially on proximal part of rim (cf. female, Figs 58-61 ).

Variation. Males. Total body length ~4.0-6.5; tibia 1 in 15 males from Mahé: 10.1-14.5 (mean 12.8); distance between tips of cheliceral apophyses: 0.67-0.76 (N = 14). Sternum sometimes without lateral dark margins; abdomen sometimes also with whitish marks; small males with cheliceral apophyses directed more towards lateral, at up to 40° against vertical line versus 25-30° in large males (i.e., maintaining a similar absolute distance between the tips).

Female.

In general similar to male (Figs 6-7 ); ventral abdominal band usually darker and wider than in males (Fig. 21 ), often divided by light lines into two or three longitudinal bands; cheliceral stridulatory files (Fig. 49 ) smaller than in males (~40 ridges), distances between ridges proximally ~6 µm, distally ~4.5 µm. Without stridulatory apparatus between carapace and abdomen. Tibia 1 in 20 females from Mahé: 9.2-14.7 (mean 12.6); body length: ~3.5-6.5. Epigynum as in Figs 22-23 and 51-52 ; main epigynal plate trapezoidal, weakly protruding, only posteriorly laterally with pair of distinctive flat processes, each with small but deep pocket at posterior extreme (arrows in Fig. 52 ), distances between pockets: 0.60-0.80 (mean 0.70) (N = 17); with pair of large pits more anteriorly on main epigynal plate, provided with numerous pores (Fig. 53 ), distance between pits: 0.27-0.42 (mean 0.34) (N = 17); distinct plate in front of epigynum with large dark median pit with smooth cuticle and without pores; posterior epigynal plate short and simple (Fig. 22 ). Internal genitalia (Figs 24-28 ) with large oval pore plates converging anteriorly, separated by V-shaped sclerite; dorsal arc with median posterior sclerotized process, ventral arc simple, without ventral median pocket (Fig. 26 ). Spigots as in male (Figs 62-63 ).

Remarks.

The Zoological Museum in Hamburg, Germany, has a further juvenile specimen labeled as holotype (ZMH-A0002275). This specimen seems to originate from the same place and the same collecting event, is very probably conspecific with the MNHN specimen, and it also fits Simon’s (1898) original description. Simon (1898) did not indicate whether one or two specimens were available to him. We assume that he did not examine the Hamburg specimen, and that it is thus not a type specimen. First, there is no label in Simon’s handwriting with the Hamburg specimen. Second, a label says "Seychellen, A. Brauer leg. 1895, Mus. Marburg, comm. 24. VII. 1901". The specimen might thus have come to Hamburg directly from Marburg rather than from E. Simon. Unfortunately, the communication from July 1901 is apparently lost (N. Dupérré, personal communication, 12 Nov. 2021).

The two specimens (male and female) examined from Silhouette are labeled as C. culiculus and originate from the same collecting event as the specimens from Jardin Marron listed in Saaristo (2001) (under C. culiculus ). The male is extremely similar to specimens from Mahé but has a smaller distance between the tips of the cheliceral apophyses: 0.61. The same is true of the female, which has a smaller distance between the pockets at the posterior epigynal margin: 0.55. In addition, the epigynum resembles Saaristo’s (2001) drawing of C. silhouette rather than his drawing of C. culiculus . However, the male bulbal processes appear indistinguishable from those of C. culiculus from Mahé. In addition, the specimens from Silhouette differ from those of Mahé by a lighter clypeus and a median carapace band that is narrower in the central part. The assignment of these specimens is thus tentative, and the separation of C. culiculus and C. silhouette clearly needs further study.

Natural history.

Adult specimens were mostly found in large sheltered spaces near the ground, between rocks and roots (arrow in Fig. 3 ). Juveniles often occupied more exposed habitats, among the vegetation up to 2 m above the ground. The domed sheet webs of adults (Fig. 4 ) had a diameter of ~20-40 cm. No silk balls were seen in the webs. When disturbed, the spiders tended to run towards the back, i.e. deeper into the shelter, rather than to vibrate or swing their bodies. However, they were often seen to bob or rotate their abdomens without any obvious disturbance. When caught, they were extremely quick at autotomizing one or more legs.

Distribution.

Apparently present on Mahé and Silhouette, but see Remarks above.

Figures

Figures 5 - 11. Cenemus culiculus (Simon, 1898), live specimens and male pedipalp. 5 - 6 Male and female from Mahe, Bel Ombre. 7 - 8 Female with egg-sac and juvenile male from Mahe, Morne Blanc. 9 - 11 Left male palp, prolateral, dorsal, and retrolateral views; male from Mahe, Morne Blanc (ZFMK Ar 23868). Abbreviations: co, coxa; fe, femur; gb, genital bulb; pa, patella; pr, procursus; ta, tarsus; ti, tibia; tr, trochanter. Scale bar: 0.5 mm.

Figures 12 - 17. Cenemus culiculus (Simon, 1898); male from Mahe, Morne Blanc (ZFMK Ar 23868). 12 - 13 Chelicerae, frontal and lateral views. 14 - 17 Left genital bulb, distal, prolateral, dorsal, and retrolateral views. Abbreviations: bs, basal sclerite; hu, ventral hump; pp, prolateral process of distal sclerite; rp, retrolateral process of distal sclerite. Scale bars: 0.5 mm.

Figures 18 - 20. Cenemus culiculus (Simon, 1898); male from Mahe, Morne Blanc (ZFMK Ar 23868); left tarsus and procursus, prolateral, dorsal, and retrolateral views; arrows point at distal dorsal sclerite. Scale bar: 0.5 mm.

Figures 21 - 23. Cenemus culiculus (Simon, 1898); female from Mahe, Bel Ombre (ZFMK Ar 23866). 21 Abdomen, ventral view. 22 - 23 Epigynum, ventral and lateral views. Scale bars: 1 mm (21); 0.5 mm (22 - 23).

Figures 24 - 28. Cenemus culiculus (Simon, 1898); female from Mahe, Morne Blanc (ZFMK Ar 23869). 24 - 25 Cleared genitalia and anterior plate, ventral and dorsal views. 26 Cleared genitalia, dorsal view, with dorsal arc tilted backwards. 27 - 28 Cleared genitalia, ventral and dorsal views. Abbreviations: da, dorsal arc; va, ventral arc. Scale bars: 0.5 mm.

Figures 29 - 37. Cenemus culiculus (Simon, 1898); male from Mahe, Morne Blanc (ZFMK Ar 23868). 29 Ocular area and carapace, dorsal-frontal view. 30 Left eye triad and AME, oblique frontal view (arrows: " accessory lenses "). 31 Gonopore. 32 Spinnerets. 33 - 34 Modified hair on cheliceral apophysis. 35 Pores on frontal cheliceral face. 36 Cheliceral stridulatory file. 37 Palpal coxa (endite), prolateral view. Scale bars: 100 µm (29, 30, 36); 10 µm (31 - 35); 20 µm (37).

Figures 38 - 46. Cenemus culiculus (Simon, 1898); male from Mahe, Morne Blanc (ZFMK Ar 23868). 38 Stridulatory pick on palpal femur. 39 Palpal tarsal organ. 40 Procursus tip, ventral part in retrolateral view. 41 Procursus, retrolateral view (arrow: distal dorsal sclerite). 42 Hair-brush on procursus. 43 - 44 Distal bulbal sclerite (arrows: sperm duct opening). 45 Membranous processes on distal bulbal sclerite. 46 Tip of long membranous processes on distal bulbal sclerite. Abbreviations: pp, prolateral process of distal sclerite; rp, retrolateral process of distal sclerite. Scale bars: 10 µm (38 - 40, 42, 45, 46); 100 µm (41, 43); 20 µm (44).

Figures 47 - 54. Cenemus culiculus (Simon, 1898); female from Mahe, Morne Blanc (ZFMK Ar 23869). 47 Carapace pit. 48 AME and clypeus, oblique frontal view (arrow: modified area). 49 Cheliceral stridulatory file. 50 Pores on frontal cheliceral face. 51 Epigynum and anterior sclerite, lateral-ventral view. 52 Epigynum, ventral view (arrows: pockets). 53 Epigynal pit. 54 Internal female genitalia, dorsal view with dorsal arc tilted toward front (asterisk: pore plate). Abbreviations: da, dorsal arc; va, ventral arc. Scale bars: 100 µm (47, 48, 51, 52, 54); 20 µm (49); 10 µm (50, 53).

Figures 55 - 63. Cenemus culiculus (Simon, 1898); female from Mahe, Morne Blanc (ZFMK Ar 23869). 55 Palpal tarsal organ. 56 Left tarsus 3, showing distinct pseudosegmentation. 57 Tip of left tarsus 2 (arrow: tarsal organ). 58 - 59 Tarsal organ on tarsus 1. 60 - 61 Tarsal organs on tarsi 3 and 4. 62 - 63 Spinnerets. Scale bars: 10 µm (55, 58 - 63); 100 µm (56); 20 µm (57).

Figures 3 - 4. Typical habitat of Cenemus culiculus (Simon, 1898) on Mahe, Casse Dent (arrow points at preferred microhabitat of adults), and web of C. culiculus (Mahe, Bel Ombre).