Cornifronus Jin & Zhang, 2024

Jin, Chi, Li, Liangtao & Zhang, Feng, 2024, Cornifronus gen. nov., a new dark sac spider genus from China (Araneae: Trachelidae), Zootaxa 5415 (3), pp. 392-400 : 393-398

publication ID	https://doi.org/ 10.11646/zootaxa.5415.3.2
publication LSID	lsid:zoobank.org:pub:D74D51EA-3888-4583-A72A-E3B0B9C1DD3C
DOI	https://doi.org/10.5281/zenodo.10693204
persistent identifier	https://treatment.plazi.org/id/EB5E87D0-B80F-FFCE-FF33-A264D7DDFD78
treatment provided by	Plazi
scientific name	Cornifronus Jin & Zhang
status	gen. nov.

Treatment

Genus Cornifronus Jin & Zhang , gen. nov. (Ħĸuoi)

Type species: Cornifronus simplex sp. nov.

Diagnosis. Cornifronus gen. nov. can be recognized from all other trachelid genera by the middle of the clypeus with a compressed conical horn-like projection ( Figs 1C, G View FIGURE 1 ). Cornifronus gen. nov. is similar to Capobula and Orthobula in the small body size (less than 3 mm), the deep pits on the carapace ( Figs 1A, E View FIGURE 1 ), the large number of paired ventral spines on the anterior legs, and the absence of ventral cusps in both sexes ( Figs 2A, B View FIGURE 2 ).

In addition, Cornifronus gen. nov. resembles Capobula in having the palpal tegulum not inflated and the small bursae without spherical sclerotized bases, but can be distinguished from it by: 1) abdomen with distinct X-shaped markings and carapace with deep pits over the entire surface ( Figs 1A, E View FIGURE 1 ), whereas abdomen without distinguishing markings and pits absent along the midline of carapace in Capobula ( Haddad et al. 2021: figs 3–10); 2) male palp without patellar apophysis ( Figs 3D, E View FIGURE 3 ), whereas present in Capobula ( Haddad et al. 2021: fig. 49); 3) copulatory ducts extremely short and inconspicuous, whereas long and directed posteriorly in Capobula ( Fig. 3B View FIGURE 3 ; Haddad et al. 2021: figs 60, 66); and 4) primary spermathecae posteriorly positioned ( Fig. 3B View FIGURE 3 ), whereas laterally positioned in the latter ( Haddad et al. 2021: figs 60, 66). Cornifronus gen. nov. resembles Orthobula in having distinct Xshaped markings on abdomen and the absence of a patellar apophysis in male palp, but can be distinguished from it by: 1) palpal tegulum not inflated and its width significantly smaller than the latter ( Fig. 3C View FIGURE 3 ; Haddad et al. 2022: figs 62, 68); 2) embolus uncoiled, whereas finely coiled in Orthobula ( Fig. 3C View FIGURE 3 ; Haddad et al. 2022: figs 88, 93); 3) femoral apophysis spine-like and tibial apophysis lamellar ( Fig. 3E View FIGURE 3 ), whereas respectively finger-like and triangular in Orthobula ( Haddad et al. 2022: figs 63, 69); 4) copulatory openings positioned medially ( Figs 3A View FIGURE 3 , 4D View FIGURE 4 ), while positioned anteriorly in Orthobula ( Haddad et al. 2022: figs 54, 59); and 5) bursae small and without sclerotized bases ( Fig. 3B View FIGURE 3 ), whereas large and with spherical sclerotized bases in the latter ( Haddad et al. 2022: figs 55, 60).

Etymology. The genus name is a combination of the Latin words corniger, meaning horned, and frons, meaning clypeus, referring to the clypeus with a horned projection. Gender is masculine.

Description. Small spiders, 1.65–2.43mm in length; carapace yellowish brown to dark brown, lateral margins with broad dark radial markings, inconspicuous ( Figs 1A, E View FIGURE 1 ); carapace elongate oval, broadest at coxae II, eye region broad; fovea reduced, only a short shallow depression; posterior margin narrow and straight; carapace surface finely granulose, with series of deep pits forming striate patterns over entire surface ( Figs 1A, E View FIGURE 1 ); surface sparsely covered with scattered fine curved setae. All eyes surrounded by black rings except PME ( Figs 1C, G View FIGURE 1 ); PME tapeta forming a 90° angle; AER obviously procurved in anterior view ( Figs 1D, H View FIGURE 1 ), slightly recurved in dorsal view; AME significantly smaller than ALE; AME separated by approximately 1/2 their diameter, similar as separation between AME and PLE; PER recurved in dorsal view, PME oval, PLE round ( Figs 1C, G View FIGURE 1 ); PME and PLE similar in diameter; median ocular quadrangle narrower anteriorly than posteriorly, length and posterior width approximately equal. Clypeus with compressed conical horned projection in middle, appearing triangular in dorsal view, often with an irregular verrucose apex ( Figs 1C, G View FIGURE 1 ); clypeus height more than 2x AME diameters; chilum indistinct; cheliceral promargin with three teeth, separated by more than their basal width, proximal tooth smallest, median tooth slightly larger than distal; retromargin with two teeth, close together, proximal tooth significantly larger than distal; cheliceral escort seta present ( Figs 1D, H View FIGURE 1 ); fang with distinct serrula; endites convergent, notched laterally ( Figs 1B, F View FIGURE 1 ), with distinct serrula, dense maxillar hair tuft on mesal margins; labium trapezoidal, subequal in length and width or slightly wider than long. Pleural bars weakly sclerotised, isolated; sternum shield-shaped, longer than broad, surface smooth with deep pits, sparsely covered in long straight setae ( Figs 1B, F View FIGURE 1 ); precoxal triangles present, intercoxal sclerites present between all coxal pairs.

Leg formula 4123, legs I and IV very similar in length; sparsely covered in long fine setae; color of legs gradually pale from proximal to distal end, from reddish-brown to light yellow; all femora distally white, femora II–IV proximally white ( Figs 2A–D View FIGURE 2 ); tibiae I and II distally white ( Figs 2A, B View FIGURE 2 ); all patellae, tibiae and metatarsi with black stripes laterally ( Figs 2A–D View FIGURE 2 ). Coxa I without retrocoxal hymen, but with three small rounded pits arranged in a triangle ( Figs 2E, F View FIGURE 2 ); all femora strongly constricted proximally, femora I and II with dorsal and ventral setal bases tuberculate, especially on ventral surface ( Figs 2A, B View FIGURE 2 ); anterior legs with strong paired ventral spines on tibiae, metatarsi and tarsi ( Figs 2A, B View FIGURE 2 ); trichobothria present on tibiae, metatarsi and tarsi; metatarsi III and IV with ventral preening comb at distal end ( Figs 2C, D View FIGURE 2 ); tarsi with pair of short trichobothria at middle; paired tarsal claws short, with three teeth and moderately dense tenant setae forming claw tufts in between; palpal claw simple, without teeth. Abdomen oval, clearly larger in females than males, with dorsal scutum in males only ( Figs 1A, E View FIGURE 1 ); dorsum with sparse fine setae and two pairs of sigilla, prominent in females, indistinct on scutum in males; abdominal black markings covering almost entire dorsum, exposing the cream background forming an X ( Figs 1A, E View FIGURE 1 ). Venter without post-epigastric sclerites, with inconspicuous ventral sclerite only in males that is wider than long ( Fig. 1F View FIGURE 1 ); four longitudinal rows of small inframamillary sclerites present in both sexes ( Figs 1B, F View FIGURE 1 ); middle with longitudinal black band in females ( Fig. 1B View FIGURE 1 ). Spinnerets: spigots not examined in detail; in females, anterior lateral spinnerets separated, posterior lateral spinnerets without distinct terminal segments; posterior median spinnerets enlarged, slightly flattened laterally, with truncated ends; male spinnerets similarly stout.

Female epigyne with small hole-like copulatory openings closely to each other, positioned medially in epigyne, in almost same transverse plane as anterior margin of posteriorly positioned primary spermathecae ( Figs 3A View FIGURE 3 , 4D View FIGURE 4 ); copulatory ducts inconspicuous, extremely short; anteriorly positioned bursae small, kidney-shaped, membranous, posteriorly with semi-membranous tubes attached to copulatory openings ( Figs 3B View FIGURE 3 , 4E View FIGURE 4 ); primary spermathecae obliquely oval, separated by approximately 1/2 their length, anteriorly inner side with short transverse ducts connecting to copulatory openings ( Fig. 3B View FIGURE 3 ); fertilization ducts originating on posteromedian surface of primary spermathecae.

Male palpal femur with short spine-like ventral apophysis at 2/3 its length, inserted on slightly elevated hump ( Figs 3D, E View FIGURE 3 ); patella without apophysis; tibia with broad and short lamellar retrolateral apophysis ( Figs 3E View FIGURE 3 , 4C View FIGURE 4 ). Tegulum pear-shaped, base broad, moderately expanded on prolateral side, tapering distally, broader than cymbium ( Figs 3C View FIGURE 3 ); ventrally with hood-like groove in center, opening towards prolateral side proximally ( Figs 3D View FIGURE 3 , 4B View FIGURE 4 ); sperm duct running down mid-retrolateral side of tegulum in ventral view, with single basal loop; embolus short, spike-like, slightly curving retrodistally, with triangular base ( Figs 3C View FIGURE 3 ); tegulum without any other structures.