Trachecymbius Haddad & Lyle 2024, gen. nov.
Creators: name: Haddad, Charles R.
name: Lyle, Robin
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Trachelidae
Trachecymbius

description: Trachecymbius gen. nov.
Type species. Trachecymbius tyume sp. nov.
Etymology. The genus name is a contraction of the genus name Trachelas, and the morphological structure “cymbium”, containing the male copulatory organs, and refers to the strongly developed retrobasal cymbial apophysis in this genus. Gender masculine.
Diagnosis. Males of the new genus share with Falcaranea gen. nov. the strongly recurved posterior eye row with widely separated eyes and the presence of a retrobasal cymbial process, but this process is considerably larger and the embolus is short and originates distally in Trachecymbius gen. nov., while in Falcaranea gen. nov. the process is small and the embolus is long and slender, originating mesally on the tegulum. Females can be distinguished by the almost parallel connecting ducts of the spermathecae, in their distal section at least, and the bilobed ST I, while in Falcaranea gen. nov. the connecting ducts are oblique and the ST I are single-lobed and oval in shape.
Description. Small spiders, 2.16–3.24 mm in length; carapace bright orange-brown to dark brown (Figs 170, 175, 215–221); carapace oval, broadest at posterior of coxae II, eye region narrowed; fovea indistinct, a short shallow depression; posterior margin of carapace very slightly concave (Figs 180, 189); carapace surface granulate, more prominent along lateral slopes, with posterior slope usually lacking tubercles (Figs 180–183, 189); carapace elevated from clypeus to behind posterior eyes, slightly convex dorsally, highest at ¾ carapace length, with steep posterior slope (Figs 171, 176). All eyes surrounded by black rings (Figs 170, 175, 215–221); AER procurved in anterior view (Fig. 182), slightly recurved in dorsal view (Figs 183, 190), AME approximately ¾ ALE diameter; AME separated by approximately ½ their diameter, nearly touching ALE (Fig. 182); PER strongly recurved in dorsal view (Figs 183, 190); PME slightly smaller than PLE; PME separated by distance approximately equal to their diameter, from PLE by distance slightly larger than PME diameter; MOQ narrower anteriorly than posteriorly, length and posterior width approximately equal. Chilum indistinct, single, a narrow transverse sclerite; cheliceral promargin and retromargin usually with two teeth each, cheliceral escort seta present (Figs 185, 186); fang with distinct serrula; endites straight or slightly concave laterally (Figs 184, 191), with distinct serrula comprising sharp, straight denticles (Figs 185, 192); dense maxillar hair tuft on mesal margins (Figs 184, 191); labium trapezoidal, slightly wider than long. Pleural bars sclerotised, isolated; sternum subpentagonal, ¾ as broad as long; surface smooth, setal bases in shallow pits, with more distinct ridges laterally, each containing a short straight seta (Figs 187, 193); precoxal triangles present, intercoxal sclerites present between coxae I and II and II and III only. Leg formula 1423 in males, 4132 in females, all segments sparsely covered in long fine setae; femora I with mesal convex curvature, all femora strongly constricted proximally (Figs 173, 178, 188); patellar indentation on retrolateral side narrow, with lyriform organ at proximal end; anterior legs with strong tubercles with setae on tibiae, metatarsi and tarsi, more pronounced ventrally (Figs 198–203); metatarsi with sparse chemosensory setae and trichobothria dorsally, weakly developed dorsal metatarsal stopper, and ventral preening brush at distal end of legs III and IV (Figs 204–206); tarsi with sparse tactile hairs, few dorsal trichobothria and chemosensory setae (Figs 207–210); trichobothria with sunken distal plate, distal margin of hood overlapping plate, hood with four curved ridges, roughly concentric (Fig. 210); tarsal organ oval, at distal end of tarsi, very slightly elevated from integument, surface finely wrinkled, opening oval and distally placed (Figs 207–209); paired tarsal claws short, with two teeth and moderately dense tenant setae forming claw tufts in between (Fig. 208); female palpal claw simple, sharply curved distally. Abdomen oval, clearly larger in females than males, without dorsal scutum in either sex, with or without markings; dorsum with very sparse fine setae and two pairs of sigilla (Figs 215–221). Spinnerets conical, short, spigots not observed in detail. Male palpal femora and patellae without apophyses, patella with lyriform organ associated with apophysis (Fig. 194); palpal tibia with small ventral RTA, cymbium with one or two distinct basal apophyses, when two, then dorsal apophysis larger than ventral (Figs 195, 213, 214); tegulum oval, broadest basally, slightly narrower than cymbium, with simple peripheral U-shaped sperm duct (e.g. Fig. 224); embolus originating prodistally, variable in shape, curving retrodistally, associated with sclerotized tegular apophysis (Figs 196, 197, 213). Female epigyne with broad paired copulatory openings positioned anteriorly or centrally in epigyne; copulatory ducts directed anteriorly, entering small anterior or lateral ST II; connecting ducts of spermathecae narrow, converging or running parallel to each other to posterior of epigyne, entering bilobed ST I on their mesal margin.
Composition. Five species, all newly described: Trachecymbius bosselaersi sp. nov., T. felis sp. nov., T. peterwebbi sp. nov., T. tyume sp. nov. and T. umbella sp. nov.
description: Published as part of Haddad, Charles R. & Lyle, Robin, 2024, Three new genera of arboreal dark sac spiders from southern Africa (Araneae: Trachelidae), pp. 451-504 in Zootaxa 5399 (5) on pages 486-489, DOI: 10.11646/zootaxa.5399.5.1, http://zenodo.org/record/10517393