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

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http://dx.doi.org/10.3897/zse.95.36762

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scientific name

Tetragnatha mandibulata Walckenaer, 1841
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Tetragnatha mandibulata Walckenaer, 1841  Figs 11View Figure 11, 12View Figure 12, 13View Figure 13, 20DView Figure 20, 21 R–XView Figure 21, 22DView Figure 22

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–CView Figure 11), chelicerae with pointed undivided apophyses ( Figs 11 D–GView Figure 11, 13AView Figure 13), Gu extremely distinctive, thick, bulky and distally projected, followed by a tiny U2, contiguous to Gu ( Figs 11D, EView Figure 11, 13AView Figure 13), two very small and almost connected AXl and Gl ( Figs 11E, FView Figure 11, 13BView Figure 13) and palps with shorter tibias (ca 3 × longer than large); conductor tips projected, large, flattened and winglet-shaped ( Figs 11 H–JView Figure 11, 13E, FView Figure 13, 20DView Figure 20) 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 1KView Figure 1, 3DView Figure 3, 11KView Figure 11, 13E, GView Figure 13, 14I, JView Figure 14, 16 D–FView Figure 16). Differing from T. bogotensis  , the translucent lobes of the other two species fill more than half of the total width of the paracymbia ( Figs 1KView Figure 1, 3DView Figure 3, 11KView Figure 11, 13GView Figure 13, 14I, JView Figure 14, 16FView Figure 16). Finally, T. mandibulata  can be distinguished from T. nitens  by the narrower lobes ( Figs 11KView Figure 11, 13GView Figure 13, 14I, JView Figure 14, 16FView Figure 16).

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–VView Figure 21; 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–VView Figure 21). 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. 21WView Figure 21; 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. 21XView Figure 21). 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. 22DView Figure 22).