Tetragnatha mandibulata Walckenaer, 1841

Castanheira, Pedro de Souza, Baptista, Renner Luiz Cerqueira, Pizzetti, Daniela Dos Passos & Teixeira, Renato Augusto, 2019, Contributions to the taxonomy of the long-jawed orb-weaving spider genus Tetragnatha (Araneae, Tetragnathidae) in the Neotropical region, with comments on the morphology of the chelicerae, Zoosystematics and Evolution 95 (2), pp. 465-505 : 474-477

Tetragnatha mandibulata Walckenaer, 1841 Figs 11 , 12 , 13 , 20D , 21 R–X , 22D

Tetragnatha mandibulata Walckenaer 1841: 211 (♂ ♀).

Tetragnatha confraterna Banks 1909: 207, pl. 6, fig. 34 (♂ ♀) syn. nov.

Tetragnatha necatoria Tullgren 1910: 149, pl. 3, fig. 72 (♂) syn. nov.

Tetragnatha petrunkevitchi Caporiacco 1947: 24 (♂ ♀) syn. nov.

Tetragnatha petrunkevitchi : Caporiacco 1948: 646 (♂)

Tetragnatha infuscata Benoit 1978: 667, fig. 2D, E (♂); Saaristo 2003: 23, figs 21A, B, 25 (removed from syn. with T. boydi ) syn. nov.

Type material.

Tetragnatha mandibulata : GUAM: ♂♀ syntypes, Mariana Archipelago, not located. Tetragnatha confraterna : COSTA RICA: ♂♀ syntypes, Machuca (Coll. P. Biolley); Escazii (Coll. J. F. Tristan); 3♂ 1♀ 1 immature, Tiribi (Coll. J. F. Tristan, MCZ 79139) and 2♂, Esparte (Coll. P. Biolley, MCZ 20875), examined (photos). Tetragnatha necatoria : TANZANIA: ♂ holotype, Pare (Coll. Kimela, NHRS-GULI0000069808), examined (photos). Tetragnatha petrunkevitchi : GUYANA: 2♂, 5♀, 6j syntypes, Konawaruk ( “Conwarook”), Potaro-Siparuni (18.iii.1937, MRAC 527), examined; 1♂ syntype, Hyde Park, Georgetown, Demerara-Mahaica (18.iv.1936, MRAC 528), examined; 1♂, 2♀, 1j syntypes (1♂, 1♀, 3j in the museum’s catalog), Garraway Landing, Potaro-Siparuni (30.vi.1936, MRAC 529), examined. Tetragnatha infuscata : SEYCHELLES: ♂, holotype, Mahé (Coll. P. L. G. Benoit & J. J.Van Mol, 24.vi.1972, MRAC 143319), examined (photos).

Diagnosis.

For females, see the extended diagnosis of T. bogotensis . Males can be distinguished by the elongated body ( Fig. 11 A–C ), chelicerae with pointed undivided apophyses ( Figs 11 D–G , 13A ), Gu extremely distinctive, thick, bulky and distally projected, followed by a tiny U2, contiguous to Gu ( Figs 11D, E , 13A ), two very small and almost connected AXl and Gl ( Figs 11E, F , 13B ) and palps with shorter tibias (ca 3 × longer than large); conductor tips projected, large, flattened and winglet-shaped ( Figs 11 H–J , 13E, F , 20D ) and paracymbia with divided notches and large membranous translucent lobes that constitute the mesal halves of the notches, as in T. bogotensis and T. nitens ( Figs 1K , 3D , 11K , 13E, G , 14I, J , 16 D–F ). Differing from T. bogotensis , the translucent lobes of the other two species fill more than half of the total width of the paracymbia ( Figs 1K , 3D , 11K , 13G , 14I, J , 16F ). Finally, T. mandibulata can be distinguished from T. nitens by the narrower lobes ( Figs 11K , 13G , 14I, J , 16F ).

Synonymy and notes.

We identified many specimens of T. mandibulata from northern to southeastern Brazil. Unfortunately we were not able to study the type material of this species from Guam. It was not available at the MNHN and NHM and is likely lost. However, this well-known and widely distributed species has been repeatedly redescribed and illustrated in many papers (e.g. Simon 1900; Gravely 1921; Okuma 1983, 1987).

After comparing our specimens with illustrations from redescriptions, we noticed close similarities between T. mandibulata and T. confraterna ( Fig. 21 R–V ; Chickering 1957c: 312, figs 19-26; Okuma 1992: 223, fig. 4), similar to Okuma (1983), who pointed out that both species might be synonyms. Banks (1909) described T. confraterna from Costa Rica and published a simple illustration of the male chelicerae. Later on, Chickering (1957c) and Okuma (1992) provided better illustrations of chelicerae and genitalia of specimens from Panama and Costa Rica, respectively. Okuma (1992) also redescribed T. confraterna based on many specimens from various localities in Costa Rica and reaffirmed its relationship with T. mandibulata , acknowledging that T. confraterna "may be barely distinguished from the latter by the female cheliceral fang" ( Okuma 1992: 225). We received photos of five males and one female syntypes from two different vials, all bearing the diagnostic characters of T. mandibulata ( Fig. 21 R–V ). Based on the characteristic morphology of males and females of T. mandibulata , we consider the small differences pointed out in Okuma (1992) as representing intraspecific variation, and we propose that T. confraterna is a junior synonym of T. mandibulata .

Tetragnatha necatoria Tullgren, 1910 was based on a male specimen from the Pare Mountains in Tanzania. After studying one photo of the upper row of teeth of this male holotype and the original illustration of the distal part of the left chelicera of this species ( Fig. 21W ; Tullgren 1910: fig. 72), we noticed the large Gu had the U2 adjoined, which is typical of T. mandibulata . So, T. necatoria is a junior synonym of T. mandibulata .

We received photos of one of the many specimens of T. petrunkevitchi Caporiacco, 1947 from Potaro and Georgetown, Guyana. This female (MRAC 529) clearly belongs to T. nitens , but there are also four specimens of T. mandibulata in the same vial. Additionally, all specimens in vials MRAC 527 and MRAC 528 are T. mandibulata , but the male and only adult specimen (amongst 25 immatures) in the vial MRAC 530 also belong to T. nitens . As the illustrations of chelicerae by Caporiacco (1948: figs 51, 52) of male and female specimens that he had preliminarly described in 1947 also match well with T. mandibulata , we conclude this species is another junior synonym of T. mandibulata .

Finally, based on photos of the male holotype of T. infuscata from the Seychelles (MRAC 143319), we observed that it also has the diagnostic characters of T. mandibulata ( Fig. 21X ). Saaristo (2003: figs 21A, B, 25; 2010: figs 27, 31) illustrated the genitalia of one male and one female from the same locality and placed this species in the synonymy of T. boydi (= T. bogotensis ), but without any evidence for his claim. Ironically, Saaristo (1978: 121, figs 224-231) was the first to correctly identify T. mandibulata from the Seychelles and gave reliable illustrations of the typical female chelicerae and much elongated genital fold. However, Saaristo (2003, 2010) unexplicably considered his former identification as erroneous and attributed it to T. boydi instead. Hence, we correct this misidentification, removing T. infuscata from the synonymy with T. boydi , and consider it to be a junior synonym of T. mandibulata .

Variation.

Males (n = 6): total length, 7.12-11.89; females (n = 20): total length, 7.54-11.63.

Distribution.

Known from Africa, Asia, Australia, Central America, the Caribbean, and South America (Brazil and Guyana) ( Fig. 22D ).

Figures

Figure 1. Tetragnatha bogotensis Keyserling, 1865, male (SMF 0035). A. Dorsal habitus; B. Ventral habitus; C. Chelicerae upper row and eyes; D. Chelicerae lower row and maxilla; E-H. Left chelicera: E. Upper view; F. Inner view; G. Lower view; H. Outer view; I-K. Left male palp: I. Mesal view; J. Dorsal view; K. Ventral view (paracymbium). Scale bars: 2 mm (A, B); 1 mm (C, D, E, F, G, H); 0.5 mm (I, J, K).

Figure 3. Tetragnatha bogotensis Keyserling, 1865, SEM photos. A. Left male palp, mesal view (MCTP 4299); B. Left male chelicera, upper view (MCTP 4299); C. Left female chelicera, upper view (MCTP 4299); D. Left male palp paracymbium, ventral view (SMF 0044); E. Left palp conductor detail, mesal view (MCTP 4299); F. Epiandrous field, ventral view (SMF 0044). Scale bars: 0.2 mm (A); 0.5 mm (B, C); 0.1 mm (D); 0.05 mm (E); 0.02 mm (F).

Figure 11. Tetragnatha mandibulata Walckenaer, 1841, male (SMF 1356). A. Dorsal habitus; B. Lateral habitus; C. Ventral habitus; D-G. Left chelicera: D. Upper view; E. Inner view; F. Lower view; G. Outer view; H-K. Left male palp: H. Mesal view with tibia; I. Mesal view detail; J. Dorsal view; K. Ventral view (paracymbium). Scale bars: 2 mm (A, B, C); 1 mm (D, E, F, G); 0.5 mm (H); 0.2 mm (I, J, K).

Figure 12. Tetragnatha mandibulata Walckenaer, 1841, female. A. Dorsal habitus (SMF 1552); B. Lateral habitus (SMF 1552); C. Ventral habitus (SMF 1552); D-G. Left chelicera (SMF 1552): D. Upper view; E. Inner view. F. Lower view; G. Outer view; H, I. Genital area: H. Genital fold, ventral view (SMF 1552); I. Internal genitalia, cleared, ventral view (SMF 1124). Scale bars: 2 mm (A, B, C); 1 mm (D, E, F, G, H); 0.1 mm (I).

Figure 13. Tetragnatha mandibulata Walckenaer, 1841, SEM photos. A. Left male chelicera, upper view (SMF 1356); B. Left male chelicera, lower view (SMF 1356); C. Left female chelicera, upper view (SMF 1552); D. Left female chelicera, lower view (SMF 1552); E. Left male palp, mesal view (SMF 1356); F. Left male palp conductor detail, mesal view (SMF 1356); G. Left male palp paracymbium, ventral view (SMF 1356); H. Epiandrous field, ventral view (SMF 1356). Scale bars: 0.5 mm (A, B, C, D, E); 0.05 mm (F); 0.1 mm (G); 0.02 mm (H).

Figure 14. Tetragnatha nitens (Audouin, 1826), male (MCTP 1426). A. Dorsal habitus; B. Ventral habitus; C-F. Left chelicera: C. Upper view; D. Inner view; E. Lower view; F. Outer view; G-J. Left male palp: G. Mesal view. H. Dorsal view; I. Ventral view (paracymbium); J. Paracymbium detail, ventral view. Scale bars, 2 mm (A, B); 1 mm (C, D, E, F); 0.5 mm (G, H, I); 0.2 mm (J).

Figure 16. Tetragnatha nitens (Audouin, 1826), SEM photos. A. Left male chelicera, upper and lower views (MCTP 1618). B. Left female chelicera, upper and lower views (MCTP 11555). C. Epiandrous field, ventral view (MCTP 1618). D. Left male palp, bulb detail, mesal view (MCTP 5985). E. Left male palp, mesal view (MCTP 5985); F. Left male palp paracymbium, ventral view (MCTP 5985). Scale bars: 1 mm (A, B); 0.1 mm (C); 0.5 mm (D, E, F).

Figure 20. Embolous and conductor tip detail, dorsal view, SEM photos. A. T. bogotensis (MCTP 4299); B. T. elongata (MCTP 43306 ex 0370); C. T. keyserlingi (MCTP 43319 ex 6944); D. T. mandibulata (SMF 1356); E. T. nitens (MACN 2252); F. T. vermiformis (MCTP 43339 ex 1133). Scale bars: 0.05 mm (A, B, C, E, F); 0.02 mm (D).

Figure 21. Junior synonyms mentioned on the manuscript. A-G. T. bogotensis synonyms chelicerae, ♂ upper view, ♀ lower view: A. T. andina, ♀ syntype; B. T. peninsulana, ♀ syntype; C. T. boydi praedator, ♂ syntype; D. T. eremita, ♂ holotype; E. T. bemalcuei, ♀ holotype; F. T. ramboi, ♂ lectotype; G. T. haitiensis, ♀ holotype; H-M. T. keyserlingi synonyms, left chelicerae: H. T. kochi, ♀ syntype upper view; I-K. T. japonica (ZMH): I. ♀ syntype upper view; J, K. ♂ T. nigrita (misidentification): J. Upper view; K. Lower view; L, M. T. conformans upper view: L. ♂ paratype; M. ♀ holotype; N, O. T. nigrita sub T. cliens, left chelicerae upper view: N. ♂ holotype; O. ♀ paratype (misidentification); P, Q. Labels of T. cliens: P. ♂ holotype; Q. ♀ paratype. R-X. T. mandibulata synonyms: R-V. T. confraterna: R. ♂ syntype right chelicera, upper view; S. ♂ syntype left chelicera, lower view; T. ♂ syntype right palp, mesal-ventral view; U. ♀ syntype right chelicera, lower view; V. ♀ syntype genital fold, ventral view; W. T. necatoria, ♂ holotype left chelicera, upper view; X. T. infuscata, ♂ holotype right chelicera, upper view.

Figure 22. Records of the material we analysed (circles), including the type localities of Neotropical junior synonyms cited in the text (stars and triangles). A. Tetragnatha bogotensis; B. Tetragnatha elongata; C. Tetragnatha keyserlingi (excluding Haiti); D. Tetragnatha mandibulata; E. Tetragnatha nitens; F. Tetragnatha vermiformis.