Guasuctenus, Polotow & Brescovit, 2019
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publication ID |
https://doi.org/ 10.11646/zootaxa.4624.4.6 |
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publication LSID |
lsid:zoobank.org:pub:B8075237-A0FD-4884-9DAA-3F76CB93528A |
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persistent identifier |
https://treatment.plazi.org/id/161387C4-5C0E-FFEB-B790-4B35376FD626 |
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treatment provided by |
Plazi |
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scientific name |
Guasuctenus |
| status |
gen. nov. |
Guasuctenus View in CoL gen. nov.
Type species. Ctenus longipes Keyserling, 1891 .
Etymology. The root word “ -gûasu ” is commonly used in the Tupi-Guarani linguistic family and it means “large”. It refers to the large size of some females of this genus that can reach almost 30 mm of total length (from carapace to opisthosoma). The Tupi-Guarani linguistic family is one of the most important of South America and include several indigenous languages spoken in the area where the genus is distributed.
Diagnosis. Guasuctenus species can be distinguished from the remaining Neotropical Cteninae by the presence of a synapomorphic cymbial dorsal projection on the male palp ( Polotow & Brescovit 2014: char. 17; Figs 5B View FIGURE 5 , 7B View FIGURE 7 ). The genus can be also diagnosed by the presence of a short and subconical RTA in the male palp ( Figs 3A View FIGURE 3 , 5A View FIGURE 5 , 6A View FIGURE 6 , 7A View FIGURE 7 ) and by the median field of the epigynum with posterior lateral excavations ( Figs 4B View FIGURE 4 , 5C View FIGURE 5 , 6B View FIGURE 6 , 7C View FIGURE 7 ).
Description. Medium to large-sized ecribellate spiders. Total body length (males and females): 16.3–29.8. Carapace piriform. Thoracic groove longitudinal. Chilum divided. Eyes: ctenoid pattern 2-4-2, with the anterior and posterior row recurved in dorsal view. Eyes round, except the anterior lateral oval. Clypeus with long, erect black bristles. Clypeus high proportional to AME diameter. Chelicerae promargin of fang furrow with three teeth, the median almost twice as high as the laterals; retromargin with four similar sized teeth ( Fig. 1A View FIGURE 1 ); intermarginal denticles present between pro and retromarginal teeth. Endites three times labium length, with external lateral margin excavated, distally truncate. Subapical serrula ( Fig. 1B View FIGURE 1 ). Labium short, as long as wide, with rounded tip bearing dense apical scopula. Sternum oval, not extending between legs IV. Trochanters deeply notched. Ventral scopula on tarsi and metatarsi dense in females and light in males. Tibiae I and II with five pairs of ventral spines and metatarsi I and II with tree pairs of ventral spines. Trichobothrial bases transversely ridged ( Fig. 1C View FIGURE 1 ). Capsulated tarsal organ with drop-shaped aperture ( Fig. 1D View FIGURE 1 ). Tarsi with two pectinate claws and dense claw tufts. Female pedipalp claw pectinate with elongated teeth ( Fig. 4A View FIGURE 4 ). Opisthosoma oval with numerous dorsal, erect black bristles. Cribellum absent. Six spinnerets, ALS ( Fig. 2A, D View FIGURE 2 ) and PLS ( Fig. 2C, F View FIGURE 2 ) two-segmented, PMS one-segmented ( Fig. 2B, E View FIGURE 2 ). ALS with PI spigots interspersed with tartipores ( Fig. 2A, D View FIGURE 2 ). ALS with a pair of large MAP spigots ( Fig. 2A, D View FIGURE 2 ). PMS lacks a paracribellum and present small AC spigots ( Fig. 2B, E View FIGURE 2 ). The female PMS have additional large CY spigots, with conical bases and long, conical shafts ( Fig. 2E View FIGURE 2 ). The PMS has two large apical spigots, with a tartipore at the side: these are probably two mAP spigots ( Fig. 2B, E View FIGURE 2 ). The conical apical segment of the PLS has numerous AC spigots ( Fig. 2C, F View FIGURE 2 ) and the females have CY spigots and elongated spigots with a cylindrical base and long, narrow shaft that is probably a MS spigot ( Fig. 2F View FIGURE 2 ).
Male palp ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 A–B, 6A, 7A–B): tibia straight, slightly shorter than cymbium; RTA short, truncated, subconical, and heavily sclerotized; ventral tibial apophysis short and rounded; cymbium elongated, distally conic and proximally subrectangular, with a posterior dorsal projection, and with a ventrobasal depression to accommodate the ventral tibial apophysis; tegulum oval, with prolateral depression to accommodate the embolus; embolus and median apophysis in a hyaline area; embolus with enlarged base and acute tip, curved retrolaterally, andwith a basal prolateral projection that notches on to a depression on the subtegulum (locking lobes sensu Griswold 1993 ); medi- an apophysis robust, prolaterally excavated and retrolaterally convex (cup-shaped sensu Griswold 1993 ); conductor laminar, wider than long and hyaline, not involving the tip of embolus; subtegulum well developed and prolaterally positioned. Epigynum ( Figs 4 View FIGURE 4 B–D, 5C–D, 6B, 7C–D): divided into median and lateral fields, which bear lateral pro- jections; median field with anterior margin deeply excavated, rounded posterior and lateral margins; lateral projec- tions short and robust, positioned medially; copulatory openings situated anteriorly; copulatory ducts short, curved; fertilization ducts short, originating from basal area of the spermathecae; spermathecae bean-shaped.
Composition. Two species, Guasuctenus longipes ( Keyserling, 1891) comb. nov. and G. vittatissimus ( Strand, 1916) new rank, new comb.
Distribution. Southern Brazil and Uruguay. Guasuctenus longipes and G. vittatissimu s present an allopatric distribution, roughly divided by the Pelotas River ( Fig. 8 View FIGURE 8 ), a tributary of the Uruguay River. Most of the records of Guasuctenus longipes occur south of the Pelotas River, while all G. vittatissimus records occur north ( Fig. 8 View FIGURE 8 ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.