Tetragnatha vermiformis Emerton, 1884

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 : 477-478

Tetragnatha vermiformis Emerton, 1884 Figs 17 , 18 , 19 , 20F , 22F

Type material.

UNITED STATES OF AMERICA: ♂ lectotype, ♀ paralectotype ( Levi 1981). ♀ lectotype, 3♀ paralectotypes in MCZ database, Beverly, Essex, Massachusetts (Coll. J. H. Emerton, 15.xiii.18xx), not examined.

Extended diagnosis.

Males and females of T. vermiformis are most similar to T. pallescens F. O. Pickard-Cambridge, 1903. Males have similar length and width of chelicerae ( Figs 17 D–G , 19A , Banks 1892: 51, pl. 5, fig. 88 as T. pallida ; Okuma 1992: 236, fig. 16 A–E); ‘T’ and ‘rsu’ very alike, sclerotized and pointed; Gl very sclerotized, thick and pointed, with a very large base, remaining teeth set apart by similar gaps. They also share similar elongated paracymbia, with finger-like notches and straight lateral knobs ( Figs 17J , 19E ; Okuma 1992: 236, fig. 16D). The epiandrous field sets this species apart as it is flat and wide, with 20 fusules in two bands ( Fig. 19F ).

Females of both species have similar small, rounded and laterally bulging chelicerae ( Figs 18 D–G , 19B ; Okuma 1992: 236, fig. 16F, G); Gu isolated from U2; Gl from L2 by large gaps, with all teeth very pointed; and similar short genital folds ( Fig. 18H ; Okuma 1992: 236, fig. 16J). Nonetheless, males and females of T. vermiformis differ from T. pallescens in having eyes much smaller and delicate and abdomen not as long and projecting ( Figs 17 A–C , 18 A–C ; Okuma 1992: 236, fig. 16H, I). Males differ by the following characters: absence of ‘sl’ ( Figs 17 D–F , 19A ); ‘a’ bending downward and closer to fang base ( Figs 17 D–G , 19A ); Gu not so close to fang base, larger and with thicker base ( Figs 17D, E , 19A ); Gu and ‘T’ placed apart from the row proper, towards lower side and following fang’s closing ( Figs 17D, E , 19A ); Gl with wider basis and close to AXl and fang basis ( Figs 17E, F , 19A ); presence of an inner cusp on fang ( Figs 17D, F , 19A ) and more elongated conductors, with thicker projected tips completely enfolding the emboli, not ending in long tails ( Figs 17 H–J , 19C, D , 20F ). Females differ in lacking both AXu and AXl and having smaller and triangular Gu, longer and wider U2, and lack of a small denticle and groove near the base of L2 ( Figs 18 D–F , 19B ; Okuma 1992: 236, fig. 16G). Females of T. vermiformis and T. pallescens have similar internal genitalia, with two curved kidney-shaped spermathecae on edge of plate, lacking central membranous sacs ( Fig. 18I ; Levi 1981: 311, fig. 131). However, T. vermiformis has longer spermathecae, without a median membranous area ( Fig. 18I ).

Variation.

Males (n = 4): total length, 6.29-7.29; females (n = 7): total length, 6.99-10.98. The spermathecal lobes are variable in size and form. Both lobes may be more regularly cylindrical and the external lobe may be much smaller than the inner one ( Levi 1981: figs 178-180) or both lobes may be curved and about the same size ( Fig. 18I ; Zhu and Zhang 2011: fig. 133H).

Distribution.

Temperate and tropical Asia, North and Central America, newly recorded from South America (Brazil) ( Fig. 22F ).

Figures

Figure 17. Tetragnatha vermiformis Emerton, 1884, male (SMF 1556). 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-J. Left male palp: H. Mesal view; I. Dorsal view; J. Ventral view (paracymbium). Scale bars, 2 mm (A, B, C); 0.5 mm (D, E, F, G); 0.2 mm (H, I, J).

Figure 18. Tetragnatha vermiformis Emerton, 1884, female. A. Dorsal habitus (SMF 1556); B. Lateral habitus (SMF 1556); C. Ventral habitus (SMF 1556); D-G. Left chelicera (SMF 1556): D. Upper view; E. Inner view; F. Lower view; G. Outer view; H, I. Genital area: H. Genital fold, ventral view (SMF 1556); I. Internal genitalia, cleared, ventral view (MCTP 43339 ex 11333). Scale bars: 2 mm (A, B, C); 0.2 mm (D, E, F, G, H, I).

Figure 19. Tetragnatha vermiformis Emerton, 1884, SEM photos (MCTP 43339 ex 11333). A. Left male chelicera, upper and lower views; B. Left female chelicera, upper and lower views; C. Left male palp, mesal view; D. Left palp conductor detail, mesal view; E. Male palp paracymbium, ventral view; F. Epiandrous field, ventral view. Scale bars: 0.5 mm (A, B, C); 0.05 mm (D); 0.1 mm (E); 0.02 mm (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 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.