Tibellus paraguensis Simon 1897
Creators: name: Achitte-Schmutzler, Helga C.
name: Rubio, Gonzalo D.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Philodromidae
Tibellus
Tibellus paraguensis

description: Tibellus paraguensis Simon, 1897
Fig. 1
Tibellus paraguensis Simon, 1897: 7 (female holotype from Paraguay, Asuncion; not examined). Tibelloides spatuliferus Mello-Leitão, 1939: 76, f. 60–62 (type from Paraguay, not examined). Tibellus paraguensis Simon. Mello-Leitão, 1945: 224 (synonymy); CAA 2016; WSC 2016. Material examined. BOLIVIA: Santa Cruz: 1♀, Chiquitos Province, S16.433, W62.167, 20 October 2010, C. Grismado, S. Avila & M. Pérez (MACN-Ar 29111). ARGENTINA: Formosa: 2Ƌ, 2♀, Fortín Quebracho, S23.867, W61.817, 8 July 2004, G. Rubio and G. Avalos (CNNE 8403); 1♀, Colonia Pastoril, S25.700, W58.233, 7 July 2006, G.
Avalos (CNNE 8404). Chaco: 2♀, Pampa del Indio, S26.267, W59.967, 12 December 2005, G. Avalos (CNNE 8379); 5♀, La Leonesa, S26.967, W58.650, 14 November 2013, G. Avalos (CNNE 8396); 2Ƌ, 2♀, 14 November 2013, G. Avalos (IBSI-Ara 0554); 1♀, Presidencia de la Plaza, S27.017, W59.633, 28 February 2003, G. Avalos (CNNE 8383); 3♀, 20 December 2006, G. Avalos (CNNE 8392); 2♀, 29 December 2006, G. Avalos (CNNE 8388); 6Ƌ, 12♀, 28 February 2007, G. Avalos (CNNE 8391); 1Ƌ, 6 March 2007, G. Avalos (CNNE 8393); 1Ƌ, 4♀, 27 april 2007, C. Alvarez Bohle (CNNE 8394); 3♀, 1 May 2007, G. Avalos and C. Alvarez Bohle (CNNE 8385), 2♀, 22 June 2007, C. Alvarez Bohle (CNNE 8386); 1Ƌ and 3♀, 26 November 2007, C. Alvarez Bohle (CNNE 8387); 12Ƌ, 9♀, 29 November 2007, C. Alvarez Bohle (CNNE 8390); 3Ƌ, Colonia Benítez, S27.317, W58.933, 19 October 2011, M.J. Escobar (CNNE 8380); 9Ƌ, 6♀, 19 November 2011, M.J. Escobar (CNNE 8381); 2Ƌ, 4♀, 10 December 2011, M.J. Escobar (CNNE 8382); 2Ƌ, 1♀, Antequeras, S27.433, W58.883, 26 November 2014, C. Achitte-Schmutzler leg (CNNE 8397); 1♀, 22 December 2014, C. Achitte-Schmutzler (CNNE 8398); 1Ƌ, 20 February 2015, C. Achitte-Schmutzler (CNNE 8399); 5♀, 23 March 2015, C. Achitte-Schmutzler (CNNE 8400); 3♀, 27 April 2015, C. Achitte-Schmutzler (CNNE 8401); 1Ƌ, 25 August 2015, C. Achitte-Schmutzler (CNNE 8402); 7Ƌ, 9♀, Basail, S27.733, W59.217, 19 November 2014, G. Avalos (CNNE 8395). Corrientes: 1♀, San Cayetano, S27.533, W58.667, 5–10 November 2007, C. Grismado, L. Piacentini, M. Izquierdo, L. Compagnucci and J. Martínez (MACN-Ar 13557); 1♀, Capital, S27.493, W58.808, 10 November 2010, A. Tacuare (CNNE 8377); 1♀, Bella Vista, S28.433, W58.917, 1 October 2005, G. Avalos (CNNE 8378).
Other material examined for comparison. Tibellus spinosus Schiapelli & Gerschman, 1941 (Paratypes: 3 females from ARGENTINA, Buenos Aires, Punta Médanus, 10 August 1960, Barrio J. Gnasso, deposited in MACN-Ar 5077).
Diagnosis. Tibellus paraguensis resembles Neotropical members of Tibellus in general body shape and color. These spiders are pale yellow, bearing numerous dark spots on the dorsal surface of the body. From T. duttoni, T. spinosus, T. affinis and T. chilensis it can be distinguished in having a shorter body (Fig. 1 D; as compared with fig. 620 in Comstock 1912, and fig. 16 in Schiapelli & Gerschman, 1942). From T. duttoni and T. insularis, female also differ by having parallel, not convergent copulatory opening guides (Fig. 1 E; compare with fig. 347 in Dondale & Redner 1978, and fig. 15 in Gertsch 1933). From T. spinosus, it also differs in having fewer macrosetae on tibiae I and II (2-2 vs. 8). Male of T. paraguensis can be distinguished from the only Neotropical known male (T. duttoni) by having a conspicuous retrolateral tibial apophysis (Fig. 1 C).
Description. Male (CNNE 8403, Figs 1 A–D) (variability in brackets): Total length 4.01 (3.36–4.89); carapace 1.58 (1.50–2.00) long, 1.47 (1.39–1.76) wide; clypeal length 0.06 (0.04–0.09); abdomen 2.00 (1.76–2.75) long, 1.00 (0.82– 1.15) wide. MOA-WA 0.07 (0.05–0.09), MOA-WP 0.16 (0.15–0.18), MOA-L 0.12 (0.12–0.15); AME-ALE 0.06 (0.05– 0.09), ALE-PME 0.06 (0.04–0.07). Leg formula 2143 (legs I and IV can be subequal in length). Leg measurements: I 6.75 (6.75–10.18) [1.90 (1.90–3.00), 0.64 (0.62–0.95), 1.87 (1.80–2.61), 1.57 (1.55–2.42), 0.77 (0.77–1.35)]; II 8.6 (8.6– 12.7) [2.44 (2.38–3.46), 0.71 (0.70–1.12), 2.31 (2.31–3.26), 2.07 (2.07–3.23), 1.07 (1.07–1.63)]; III 5.14 (5.04–7.63) [1.57 (1.57–2.41), 0.45 (0.43–0.74), 1.25 (1.21–1.82), 1.17 (1.02–1.77), 0.70 (0.66–0.92)]; IV 6.59 (6.59–9.91) [2.10 (2.05–3.12), 0.43 (0.43–0.74), 1.68 (1.56–2.48), 1.66 (1.57–2.55), 0.72 (0.71–1.05)]. Legs I and II macrosetae: femora with 1-1-1 dorsal, 1-1-1 prolateral and 1-1-1 retrolateral (smaller) distally; tibiae with 2-2-2a ventral paired, 1 dorsal distally, 1-1-1 prolateral and 1-1-1 retrolateral; metatarsus with 2-2 ventral paired, 1-1 prolateral and 1-1 retrolateral. Carapace pale yellow, covered with simple hairs with some thicker and longer setae on cephalic region and clypeus; numerous black spots, present mostly on carapace margins and cephalic region. Thoracic region with a dark brown elongated spot, just behind fovea; thoracic groove slightly marked. Clypeus with sclerotized edges at outer corner of chelicerae bases. Chelicerae with two promarginal teeth, no teeth on retromargin. Sternum pale yellow, with some black marginal spots. Abdomen white, reticulated, with a pale yellow dorsal stripe, which extends from the front to the middle of the abdomen, ends with a dark brown spot; dorsally covered with sparse black, short, and thick setae. Numerous black spots form a pair of longitudinal bands on the lateral margins, and a pair of dorsal bands whose density points increases towards posterior end; ventral side pale, without spots. Legs thin and long, pale yellow-orange; covered with some hairs and numerous black spots. Metatarsus and tarsus scopulate. Palp: cymbium with four spines; embolus only partly visible, tip extends beyond tegulum, claw-shaped, slightly and prolaterally curved. Conductor small translucent, originating apically on tegulum. Retrolateral tibial apophysis large, ventrally directed, with two small tips, one of them more sclerotized.
Female (CNNE 8403, Fig. 1 E–F) (variability in brackets): Total length 5.15 (5.15–7.10); carapace 1.73 (1.73–3.81) long, 1.59 (1.53–2.07) wide; clypeal length 0.15 (0.09–0.22); abdomen 3.29 (3.29–4.75) long, 1.66 (1.59–2.31) wide. MOA-WA 0.07 (0.07–0.13), MOA-WP 0.18 (0.18–0.25), MOA-L 0.15 (0.13–0.21); AME-ALE 0.07 (0.06–0.10), ALE- PME 0.09 (0.06–0.12). Leg formula 2143 (legs I and IV can be subequal in length). Leg measurements: I 6. 41 (6.41– 9.09) [1.76 (1.76–2.72), 0.71 (0.71–1.08), 1.73 (1.70–2.41), 1.36 (1.36–2.14), 0.85 (0.78–1.12)]; II 7.53 (7.53–10.93) [2.04 (2.04–3.12), 0.95 (0.91–1.25), 1.87 (1.87–2.82), 1.66 (1.66–2.55), 1.05 (0.91–1.32)]; III 4.78 (4.78–7.19) [1.36 (1.36–2.48), 0.61 (0.50–0.78), 1.08 (1.08–1.70), 1.05 (0.86–1.59), 0.68 (0.54–0.81)]; IV 5.97 (5.97–8.72) [1.97 (1.76– 2.89), 0.51 (0.51–0.75), 1.39 (1.39–2.10), 1.39 (1.39–2.07), 0.71 (0.68–1.02)]. Leg macrosetae as in male. Color and shape as in male. Epigyne: spermathecae elongated, with curved posterior extensions; a spherical spermathecal gland on anterior margin of each spermatheca; copulatory opening spherical, near anterior margin of epigyne; copulatory opening guide medium-sized, tip of guide not reaching anterior edge of spermatheca; median septum diverging anteriorly, Vshaped.
Sexual dimorphism. Males and females did not differ in their somatic morphology; only females are slightly larger than males.
Natural history. Most specimens were captured sweeping in the Chaco grasslands. Grasslands of Antequeras (Chaco) are characterized by the presence of numerous palm trees (Copernicia alba). Spiders were collected monthly, and adults were present in samples every month. Some juveniles were kept in captivity and fed on fruit flies. They are voracious and agile hunters. In the Iberá reserve (central-north of Corrientes), grasslands and marshlands were intensively sampled using a G-Vac method but no T. paraguensis were sampled.
Distribution. Southern Paraguay (Asunción) and northeastern Argentina (Misiones, Corrientes, Entre Ríos). New records from Formosa and Chaco provinces (northern Argentina), and Santa Cruz (eastern Bolivia).
Remarks. Spiders of the genus Tibellus have the carapace longer than wide, with median and marginal brown stripes, great distance between PME and PLE, long leg II, and small or absent RTA (Simon 1875). These characters distinguish Tibellus from other closely related genera such as Apollophanes O. Pickard-Cambridge, 1898. Exceptionally, in T. paraguensis the RTA is well developed, a similarity with Apollophanes; however other Tibellus species also have developed RTA, such as T. californicus Schick, 1965 and T. macellus Simon, 1875.
Tibellus differs from Argentinean genus Paracleocnemis Schiapelli & Gerschman, 1942 in the color pattern of the body, in lack of long and curved setae on the cephalic region, and in having different leg formula. According to Gertsch (1933), T. paraguensis is closely related to Cleocnemis punctulata (Taczanowski, 1872), previously included in Tibellus and later transferred to the South American genus Cleocnemis Simon, 1886 by Caporiacco (1955); this genus differs from Tibellus mainly in having stout legs with strong spines, and the tarsus without scopulae.
Evidently T. paraguensis shows some non-typical characters for the genus; e.g. the relatively short body, with lateral stripes and a dorsal band. With respect to the last character, we conclude that the stripes and band of T. paraguensis are formed by dark scattered spots, similar to African species T. kibonotensis Lessert, 1919 and T. septempunctatus Millot, 1942 (see Dippenaar-Schoeman & Van den Berg 1994).
As was noted by Efimik (1999) there are general similarities between various philodromid genera, e.g. the color pattern of T. paraguensis is the same as in Thanatus oblongiusculus (Lucas, 1846) having Palearctic distribution (Efimik 1999). However copulatory structures of Thanatus differ from Tibellus. Within these known analogies of Philodromidae, T. paraguensis has some atypical characters of the genus, but retains other diagnostic characters of Tibellus.
As alluded above, Tibellus is a genus partly revised, there are few studies concerning South American species, which increases the importance of contributions with detailed species descriptions from poorly explored but biodiversity-rich areas. Taxonomic papers should not be all or nothing; although not in a monographic context, single species description can be useful to complement existing monographs, with the aim of expanding those revisions (Rubio et al. 2013).
description: Published as part of Achitte-Schmutzler, Helga C. & Rubio, Gonzalo D., 2016, First description of the male of the spider Tibellus paraguensis Simon, 1897 (Araneae: Philodromidae), with new distribution records, pp. 146-150 in Zootaxa 4161 (1) on pages 146-149, DOI: 10.11646/zootaxa.4161.1.12, http://zenodo.org/record/272236