Trachelas L. Koch, 1872

Trachelas L. Koch, 1872: 256; O. Pickard-Cambridge 1872: 256; Chickering 1972: 215; Platnick & Shadab 1974a: 1; Platnick & Shadab 1974b: 1; Platnick 1975: 1; Paik 1991: 198; Deeleman-Reinhold 2001: 393; Bosselaers et al. 2009: 16; Zhang et al. 2009: 41; Jin et al. 2017: 46.

Type species: Trachelas minor O. Pickard-Cambridge, 1872, by original designation.

Remarks. The name Trachelas was first used by L. Koch (1866) in an identification key, but as no type species had been described in the genus, it was considered a nomen nudum. Subsequently, O. Pickard-Cambridge (1872) described Trachelas minor, formalizing the recognition of the genus. L. Koch (1872) provided a more detailed description of the genus, with its authorship being attributed to him.

Diagnosis. Trachelas sensu stricto differs from other Afrotropical genera that lack leg spines and ventral cusps on the anterior legs in males, i.e. Coronarachne Haddad & Lyle, 2024, Falcaranea Haddad & Lyle, 2024, Fuchiba Haddad & Lyle, 2008, Fuchibotulus Haddad & Lyle, 2008, Mushimane Haddad, 2025 and Trachycymbius Haddad & Lyle, 2024, by the very coarse carapace integument (shared with Fuchiba and Fuchibotulus), the presence of a male palpal patellar apophysis and the absence of a tibial apophysis (except T. scutatus sp. nov.), and by the distinct, sclerotized oval atria or curved ridges of the epigyne that are situated close to the midline.

Description ( Trachelas sensu stricto). Small spiders, 1.76–4.72 mm in length; carapace bright yellow to deep red-brown; oval, broadest at coxae II, gradually narrowed towards eye region (Figs 1A, F, 2A, 6, 7); fovea distinct, a short broad slit; posterior margin distinctly concave (Figs 6, 7); convex in lateral profile, strongly elevated from clypeus to approximately 1/3 carapace length, slightly convex in midsection, with steeper slope in posterior 1/3 (Fig. 1B, G); carapace surface coarsely granulate, with each seta accompanied by posterior transverse ridge and pair of deep depressions (Fig. 2B). All eyes surrounded by black rings; AER procurved in anterior view (Fig. 2C), slightly recurved in dorsal view (Fig. 2D); clypeus usually slightly smaller to slightly larger than AME diameter at AME, AME very slightly larger than ALE; PER slightly recurved in dorsal view (Fig. 2D); PLE usually very slightly larger than PME; MOQ narrower anteriorly than posteriorly, posterior width slightly larger than length. Chilum absent; cheliceral promargin with three teeth (Fig. 2E), retromargin with two teeth, usually on common base (Fig. 2F); fang with distinct serrula (Fig. 2F); posterior surface of paturon with field of long setae, single modified short seta and field of pores posterior to retromarginal teeth (Fig. 2G, H); endites converging slightly distally, lateral margins not parallel, mesal margins with longitudinal groove and dense maxillar hair tuft (Fig. 2I), distal margins with distinct serrula comprising elongate denticles with sharp tips (Fig. 2J); labium trapezoidal, narrower distally than proximally, length less than proximal width, distal margin with slight concavity (Fig. 2I). Pleural bars sclerotised, isolated (Fig. 1G); sternum shield-shaped, slightly longer than broad, broadest at coxa II (Fig. 1C, H), surface smooth centrally, covered in long straight setae with more pronounced tuberculate bases towards borders (Fig. 2K); precoxal triangles present, intercoxal sclerites short but usually present between all coxal pairs. Leg formula 4123 or 1423, sparsely covered in fine setae (Fig. 3B–K); leg I and II only slightly thickened compared to legs III and IV (Figs 1A–C, F–H, 6, 7); dorsal femoral surface almost straight, very slightly concave at ½ its length, ventral surface very slightly convex (Fig. 1D, I); all femora strongly constricted proximally (Fig. 1D, I); patellar indentation on retrolateral side narrow, with lyriform organ at proximal end (Fig. 3B, C); legs I and II of both sexes without ventral cusps on tibiae, metatarsi or tarsi, only with weak scopulae (Fig. 3D–K); all tibiae, metatarsi and tarsi with sparse dorsal trichobothria (Fig. 3H, I, 4B, C); metatarsi with short metatarsal stopper (Figs 3J, K, 4A), metatarsi III and IV with weak ventral preening brush and comb at distal end (Figs 3F, 4A); tarsi with sparse tactile hairs, few dorsal trichobothria and chemosensory setae (Fig. 3G, K); trichobothria with slightly lowered distal plate, distal margin of hood overlapping plate, hood with four to six roughly concentric curved ridges (Fig. 4B, C); tarsal organ at approximately 4/5 tarsus length (Fig. 3K), flush with integument, surface finely wrinkled, opening oval and distally placed (Fig. 4D); paired tarsal claws short, with eight teeth and dense tenant setae forming claw tufts in between (Figs 3G, K, 4E, F). Abdomen oval, sometimes uniformly coloured, otherwise with mottled grey markings or chevrons on creamy-grey background (Figs 1A–C, F–H, 6, 7); dorsal scutum usually in males only, only in female of T. scutatus sp. nov. (Fig. 7E), covering most of dorsum; dorsum covered in scattered short fine setae, with two pairs of sigilla in both sexes; venter without large sclerites, with paired rows of indistinct tiny sclerites from epigastric furrow to spinnerets, covered in scattered short fine setae (Fig. 1C, H). Spinnerets short, conical, in compact group, spigots only studied in detail in both sexes of T. canariensis: ALS of males with one MAmp, six Pi, a single Nu and single Ta (Fig. 4G), of females with one MAmp, seven Pi and single Ta (Fig. 4J); PMS of males only with single mAmp and five Ac (Fig. 4H), of females with one mAmp, four Cy and six Ac (Fig. 4K); PLS of males with one mAmp and six Ac (Fig. 4I), of females with two Cy and seven Ac (Fig. 4L). Male palpal femur with distinct distal ventral concavity (Fig. 5A; see also Bosselaers et al. 2009: fig. 4; Jin et al. 2017: fig. 3D); patella with triangular or hook-like retrolateral PA, with ventral patellar indentation with lyriform organ at its base (Fig. 5B–E); palpal tibiae without apophyses (except T. scutatus sp. nov., with rounded RTA), sometimes only with distal retrolateral sclerotized ridge; TE generally oval in ventral view, as broad as CY, with distinct distal TA (Fig. 5E); EM base broad, originating prodistally or distally, EM forming simple distal coil or loop (Fig. 5E). Female palpal claw simple, slightly bent distally, without teeth (Fig. 2A). Epigyne quite heavily sclerotized, with CO in oval AT or curved ridges near midline in anterior half (Fig. 5F), without hood; CD usually directed anteriorly, often looping, with terminal swelling with narrow stalk entering almost round ST II near centre (see Ramírez 2014: fig. 179D) [ST II often break off during ultrasonic cleaning of epigyne]; Cd usually looping before running posteriorly near midline of epigyne before entering oval or bilobed posterior or posterolateral ST I; Cd usually with thickened section prior to entering ST I.

Composition. Based on the current study and a review of the literature, the following species should be considered as Trachelas sensu stricto: T. canariensis Wunderlich, 1987 (Canary Islands, Spain, and East, Central and southern Africa), T. chamoli Quasin, Siliwal & Uniyal, 2018 (India), T. chubbi Lessert, 1921 (Central and East Africa), T. costatus O. Pickard-Cambridge, 1885 (Pakistan and India), T. crewsae Marusik & Fomichev, 2020 (Tajikistan), T. falsus sp. nov. (Central, West and southern Africa), T. himalayensis Biswas, 1993 (India), T. humus sp. nov. (southern Africa), T. leggi sp. nov. (South Africa), T. longinquus sp. nov. (Central African Republic), T. minor O. Pickard-Cambridge, 1872 (Europe, West Asia, North Africa), T. oreophilus Simon, 1906 (India and Sri Lanka), T. pusillus Lessert, 1923 (Central and southern Africa), T. quisquiliarum Simon, 1906 (Sri Lanka), T. russellsmithi sp. nov. (Ethiopia), T. scutatus sp. nov. (Ghana and Nigeria), T. smithi sp. nov. (Kenya), T. sylvae Caporiacco, 1949 (Central and East Africa), T. tanasevitchi Marusik & Kovblyuk, 2010 (far eastern Russia), T. uniaculeatus Schmidt, 1956 (Canary Islands) and T. vulcani Simon, 1896 (China, Indonesia and Japan).

The New World fauna, currently including 62 described species (World Spider Catalog 2025), represents a phylogenetically distinct lineage from Trachelas sensu stricto (Fig. 23; Pett et al. unpublished data) and is thus not considered further here. Several Asian species, i.e. the Chinese T. alticolus Hu, 2001, T. bomiensis Jin & Mi, 2024 (Liu et al. 2024), T. brachialis Jin, Yin & Zhang, 2017, T. gaoligongensis Jin, Yin & Zhang, 2017, T. gigapophysis Jin, Yin & Zhang, 2017, T. nanyueensis Yin, 2012 (Yin et al. 2012) and T. sinensis Chen, Peng & Zhao, 1995, as well as T. japonicus Bösenberg & Strand, 1906 from far eastern Russia, China, Japan and Korea, are likely misplaced and may belong to a new genus. Males of most of these species have ventral cusps on the anterior legs (except T. alticola and T. sinensis, apparently absent, and T. nanyuensis, not indicated in description) and a well-developed palpal tibial apophysis (often basal and posteriorly directed). Their females have an epigyne with a very different internal structure to Trachelas sensu stricto, particularly the usually elongate lateral ST II (more oval in T. japonicus) and long connecting ducts originating laterally, curving in an arch mesally then posteriorly (e.g. Zhang et al. 2009; Yin et al. 2012; Jin et al. 2017; Jin & Mi 2024; Tang et al. 2024). Furthermore, the Chinese T. fanjingshan Zhang, Fu & Zhu, 2009, T. fasciae Zhang, Fu & Zhu, 2009, T. kavanaughi Tang, Yan, Zhao & Peng, 2024, T. shilinensis Jin, Yin & Zhang, 2017, T. ventriosus Tang, Yan, Zhao & Peng, 2024 and T. zhui Li, Wang, Zhang & Chen, 2019, all known only from females, have a similar internal epigyne structure to that of the Asian species referred to above and are thus also likely to be misplaced, but confirmation of this requires discovery of their males. Trachelas devi Biswas & Raychaudhuri, 2000 (Bangladesh) has a procurved PER and very different somatic morphology and genitalia to Trachelas sensu stricto (Biswas & Raychaudhuri 2000: figs 15–21), so is likely not a trachelid and should be transferred to another family.

Key to the continental Afrotropical species of Trachelas

1. Males.............................................................................................. 2

- Females............................................................................................ 10

2. Embolus (EM) forming distinct coil or loop along its path..................................................... 3

- EM not forming coil or loop but gradually curving and tapering towards tip and bending towards prolateral side of palp (Fig. 14E, F)............................................................................ T. longinquus sp. nov.

3. EM long, forming open coil with slender distal section........................................................ 4

- EM short, forming compact coil, distal section compact or sharp but not slender................................... 7

4. EM forming two distinct loops along its path, tip blunt and situated along retrolateral side of cymbium (CY); palp with rounded retrolateral tibial apophysis (RTA, Fig. 17C, D).............................................. T. scutatus sp. nov.

- EM with only single loop along its path, tip sharp and positioned along ventral side of CY; palp without rounded RTA..... 5

5. Tegulum (TE) almost parallel-sided, broad distally, EM base almost as broad as TE (Fig. 13A); EM with sharp retrolateral bend to long slender distal section, with tip directed at 11 o’clock; patellar apophysis (PA) finger-shaped in ventral view (Fig. 13A, B).................................................................................... T. humus sp. nov.

- TE somewhat pear-shaped, narrowed distally, EM base clearly narrower, approximately half the width of TE (Figs 8A, 15A); EM with gradual looping bend, with tip directed at 1 o’clock; PA triangular or compact in ventral view (Figs 5E, 8A, 15A).. ................................................................................................... 6

6. EM almost as long as TE in ventral view, with long slender distal section; PA triangular in ventral view, with broad base almost extending entire length of patella (Figs 5B, C, E, 8A, B)............................................ T. canariensis

- EM about half the length of TE in ventral view, with thicker distal section; PA compact in ventral view, placed distally on patella (Fig. 15A, B).................................................................................. T. pusillus

7. EM curving along longitudinal axis of palp, roughly inverted 6-shaped in lateral view; sperm duct S-shaped, with strong proximal and distal bends (Figs 10A, 19A)................................................................. 8

- EM compact, curving along transverse axis of palp, with short stout tip directed distally; sperm duct only with strong proximal bend, U-shaped or forming proximal loop, gradually curving in distal section (Figs 11A, 14A)........................ 9

8. EM narrow in ventral view, with blunt tip in lateral view (Fig. 10A, B).................................... T. chubbi

- EM broad in ventral view, with sharp pointed tip in lateral view (Fig. 19A, B)............................... T. sylvae

9. Proximal section of sperm duct forming broad U-shaped bend in ventral view; proximal section of EM orientated slightly retrodistally; PA positioned near middle of patella (Fig. 14A, B).................................... T. leggi sp. nov.

- Proximal section of sperm duct forming closed loop; proximal section of EM orientated slightly retroproximally; PA positioned distally on patella (Fig. 11A, B)............................................................. T. falsus sp. nov.

10. Epigyne (EP) with distinct circular or oval atria (AT) with strongly sclerotized rims, with copulatory openings (CO) within their margins............................................................................................ 11

- EP with simple curved ridges leading to CO............................................................... 15

11. AT large, occupying almost 2/3 length of epigynal plate (Fig. 19C)........................................ T. sylvae

- AT smaller, occupying at most 1/2 length of epigynal plate (Figs 10C, 11C, 13C, 18A)............................. 12

12. AT round, as wide as long, with CO along anterior margin (Fig. 10C); copulatory ducts (CD) looping laterally, anteriorly, then mesally before entering transversely orientated secondary spermathecae (ST II) (Fig. 10D).................... T. chubbi

- AT oval, clearly longer than wide, with CO along posterior margin; CD and ST II variable, but ST II not transversely orientated.......................................................................................... 13

13. CD initially broad, narrowing rapidly; ST II lollipop-shaped; ST I pear-shaped, transversely orientated, almost twice as long as broad (Fig. 13C, D)...................................................................... T. humus sp. nov.

- CD initially narrow, parallel-sided along their length; ST II round or bilobed; ST I pentagonal or ovoid, very slightly wider than long (Figs 11C, D, 18C, D)............................................................................ 14

14. ST II round; connecting ducts (Cd) very narrow, with almost perpendicular bend and loop before entering pentagonal ST I (Fig. 11C, D)................................................................................ T. falsus sp. nov.

- ST II clearly bilobed; Cd broad, thickened and looping dorsally before making sharp bend that enters ST I (Fig. 18C, D).......................................................................................... T. smithi sp. nov.

15. Sclerotized ridges (SR) of CO small, recurved, along midline of epigyne, with narrow CD initially directed anteriorly; copulatory ducts forming complete loop laterally before entering longitudinally oval ST II (Fig. 17E–G); abdomen with dorsal scutum...................................................................................... T. scutatus sp. nov.

- SR of CO clearly separated, directed mesally (Figs 5F, 8C, 14C, 15C, 17A); copulatory ducts funnel-shaped or spiralling, initially directed mesally then anteriorly before entering round ST II (Figs 8D, 14D, 15D, 17B); abdomen without dorsal scutum............................................................................................. 16

16. ST II positioned anterolaterally in epigyne, in same plane as CD.............................. T. russellsmithi sp. nov.

- ST II positioned laterally near midpoint of epigyne, clearly posterior to CD...................................... 17

17. CD directed anteriorly then bending posterolaterally before looping to ST II; Cd forming complete loop between ST II before diverging to enter transversely oval ST I, close to epigastric furrow (Fig. 8C, D)......................... T. canariensis

- CD spiralling, initially directed mesally then anteriorly before bending back to enter ST II; Cd thickened posterior to ST II, looping laterally and forming short channel that enters ST I.................................................. 18

18. SR of CO relatively large and more than 1/2 the diameter of ST II, separated by slightly more than 2× their diameter (Fig. 14C)................................................................................... T. leggi sp. nov.

- SR of CO small and almost 1/3 the diameter of ST II, separated by approximately 3× their diameter (Fig. 15C).... T. pusillus