Paraceto, Zhang, Feng, 2017

Zhang, Feng, 2017, Description of Paraceto gen. n. and a relimitation of the genus Cetonana (Araneae: Trachelidae), Zootaxa 4320 (2), pp. 225-244 : 233-235

Paraceto gen. n.

Type species: Paraceto spiralis sp. n.

Etymology. The generic name is a combination of the prefix Para-, indicating sub-equal, accompanying, nearest, and the suffix from Cetonana , to which this genus is related. Gender feminine.

Diagnosis. Paraceto can be easily distinguished from other trachelid genera by the following distinctive characters: 1) the body entirely covered with unusual long slender hairs; 2) the large hook-shaped tibial apophysis coexists with a ventral femoral groove and patellar apophysis on male palp; 3) the well-developed cymbium, posteriorly expanded at its retrolateral base and anteriorly narrower and coiled; 4) the long embolus coiled along with the anterior portion of cymbium; 5) the epigynal plate with laterally situated copulatory openings and without any hood or ridges; 6) copulatory ducts and connecting ducts coiled towards each other.

In addition to the aforementioned characters, Paraceto differs from C. laticeps , the type species of Cetonana , by: 1) ALE largest and ALE>AME, whereas AME largest and AME>ALE in C. laticeps ; 2) clypeus height greater than diameter of AME, whereas it is smaller than diameter of AME in C. laticeps ; 3) leg cusps absent in females but present in males, whereas they are present in both sexes of C. laticeps ; 4) carapace obviously convex, whereas it is flat in C. laticeps .

Paraceto resembles the American trachelids of the genus Meriola in that only males have ventral cusps on the anterior legs, but can be distinguished from it by: 1) male tibiae I–II ventral cusps absent, whereas present in Meriola ; 2) ventral cusps short and blunt, whereas elongated and sharply pointed in Meriola ; 3) both the embolus and RTA are elongated, whereas variable in Meriola , such as the genus type M. decepta Banks, 1895 , which has both a short embolus and RTA.

Paraceto can be easily distinguished from the Afrotropical trachelids Afroceto and Patelloceto Lyle & Haddad, 2010 by leg spines are totally absent, whereas present on the anterior femora and posterior tibiae and/or metatarsi in these two genera ( Lyle & Haddad 2010). Furthermore, Paraceto differs from Afroceto by both males and females lacking a dorsal abdominal scutum, whereas males of Afroceto have a well-developed dorsal abdominal scutum covering nearly the entire abdomen, in females usually extending up to 1/3 the abdomen length; Paraceto differs from Patelloceto by the male palp, which has a small patellar apophysis and lacks a dorsal tibial apophysis, whereas Patelloceto have a very large patellar apophysis that extends past the base of the cymbium, and a distinctive large sword-like dorsal tibial apophysis.

Description. Hairy spiders, total length 4.2–5.6 mm. Carapace dark brown, densely covered with small granulations carrying unusually long, slender pale grey hairs; ocular area narrowest, broader medially and concave posteriorly; obviously convex, highest between fovea and posterior row of eyes ( Figs 7A, B ); edge of carapace distinct and slightly rebordered; ovoid in dorsal view, somewhat truncated at posterior margin; radial and cervical grooves indistinct; fovea longitudinal, short, linear.

Eyes surrounded by dark rings. AER and PER slightly recurved in dorsal view ( Figs 7F, G ). AME smaller than ALE; ALE largest ( Figs 7C, D ). AMEs separated by about 0.8 times their diameter, from laterals by about 0.3 times their diameter. PMEs separated by about 1.4 times of their diameter, from laterals by about 1.1 times their diameter. MOA length <anterior width <posterior width. Clypeus height slightly wider than diameter of AME. Chilum present, triangular, sclerotised and brown ( Fig. 7E ).

Chelicerae dark brown, covered with granulations carrying similar hairs to carapace; cheliceral boss pronounced, at ectal base; promargin with three and retromargin with two teeth; whisker setae and escort seta present distally on anterior face of paturon. Endites yellow-brown, longer than wide, without oblique depression, apex convex; labium brown, slightly wider than long. Sternum yellow-brown, shield-shaped, longer than wide, with short fine setae scattered across smooth surface; precoxal triangles and intercoxal sclerites present.

Legs covered with long hairs, without spines ( Fig. 8 ). Anterior legs yellow-brown, much stouter and darker than posterior legs. All tibiae and metatarsi with pair of black rings, one distally and one near base. Claw tufts present. Sparse, short scopulae present on tarsi and metatarsi I–II. Short ventral cusps present on tarsi and metatarsi I–II in male only, arranged sparsely in two lines ( Figs 8A–D ). Metatarsi III–IV ventrally with distal preening brush ( Figs 8E–I ). Abdomen oval, dorsum and venter densely covered with long hairs, with several chevrons posteriorly and two pairs of sigilla medially; dorsal, epigastric, and ventral scuta absent in both sexes.

Femur of male palp with a shallow, transversal ventral terminal groove; patella with a blunt apophysis; tibia with a large hook-shaped apophysis retrolaterally, with sharp tip. Tegulum with one hook-shaped apophysis apically and one prolateral apophysis; sperm duct visible in prolateral view; subtegulum almost invisible in ventral view. Cymbium elongate, ventrally curved, anteriorly narrower and coiled, posteriorly expanded at retrolateral base. Embolus well-developed, slender and coiled along with cymbium.

Epigyne with convex plate, weakly sclerotized; copulatory openings oval, laterally situated; hood absent. Vulva: copulatory ducts long, anteriorly thick and posteriorly slender, coiled spirally; ST2 large, oval or pearshaped, close to each other, situated at central part of vulva, anterior to ST1; connecting ducts thin and long, coiling around copulatory ducts; ST1 spherical and small, situated posteriorly.

Behaviour and habitat. Diurnal, wandering in foliage, captured by beating leaves and branches. Paraceto species mostly live in tree canopies on forest edges.

Composition. P. spiralis sp. n. and P. orientalis ( Schenkel, 1936) comb. n., the latter formerly placed in Cetonana .

Distribution. China.

Figures

FIGURE 7. Paraceto spiralis sp. n., A. male habitus, lateral view; B. female habitus, lateral view; C. male cephalothorax, frontal view; D. female cephalothorax, frontal view; E. same, frontal-ventral view; F. male ocular area, dorsal view; G. female ocular area, dorsal view.

FIGURE 8. Paraceto spiralis sp. n., A. male left leg I, retrolateral view; B. male left leg II, retrolateral view; C. male left metatarsus and tarsus I, ventral view; D. male left metatarsus and tarsus II, ventral view; E. male left leg III, retrolateral view; F. male left leg IV, retrolateral view; G. female left metatarsus and tarsus I, retrolateral view; H. female left leg III, retrolateral view; I. female left leg IV, retrolateral view.