Tetragnatha keyserlingi Simon, 1890,

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: 472-474

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

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scientific name

Tetragnatha keyserlingi Simon, 1890
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Tetragnatha keyserlingi Simon, 1890  Figs 8View Figure 8, 9View Figure 9, 10View Figure 10, 20CView Figure 20, 21H, I, L, M, OView Figure 21, 22CView Figure 22

Tetragnatha mandibulata  : Keyserling 1865: 848, pl. 21, figs 6-9 (♂ ♀ misidentified).

Tetragnatha mandibulata  ?: L. Koch 1872: 194, pl. 17, figs 2a, b, 3a, b (♂ ♀ misidentified).

Tetragnatha keyserlingi  Simon 1890: 134 (♂ ♀).

Tetragnatha mandibulata  : Thorell 1890: 221 (♀ misidentified)

Tetragnatha maxillosa  Thorell 1895: 139 (♂ ♀) syn. nov.

Tetragnatha kochi  Thorell 1895: 140 (♂ ♀) syn. nov.

Tetragnatha japonica  Bösenberg and Strand 1906: 177, pl. 15, fig. 409 a–d (♂ ♀).

Tetragnatha conformans  Chamberlin 1924: 9, pl. 2, figs 13-15 (♂ ♀).

Tetragnatha propioides  Schenkel 1936: 89, fig. 31 (♂ ♀).

Tetragnatha ethodon  Chamberlin and Ivie 1936: 64, pl. 17, figs 144-146 (♂ ♀) syn. nov.

Type material.

Tetragnatha keyserlingi  : COLOMBIA [Neu Granada]: ♂ ♀ syntypes, not located. Tetragnatha maxillosa  : INDONESIA: ♀ syntype, Java, not located; SINGAPORE: ♂ ♀ syntypes (Coll. Workman), not located. Tetragnatha kochi  : ♂ ♀ syntypes, FIJI (Ovalau), not located; TONGA, not located; SAMOA (Upolu) [2♀ sub T. mandibulata  , Mus. Godeffroy collection, 1869 ( NHRS-GULI000069809)], examined (photos). Tetragnatha japonica  : JAPAN: 10♂, 5♀ syntypes, Saga (Yunohama Mountain) (Coll. W. Dönitz, 25.v.1881, SMF 4212-121), not examined; 3♀ syntypes, 2♂ (misidentified), Osaka ( ZMH), examined (photos). Tetragnatha conformans  : CHINA: ♀ holotype, ♂ paratype, Suzhou [Soochow] on the labels, Kuliang on the publication (Coll. N. Gist Gee, USNM 865), examined (photos). Tetragnatha propioides  : CHINA: ♂ ♀ syntypes, Sichuan, not located. Tetragnatha ethodon  : PANAMA: ♂ holotype, Barro Colorado Island ( AMNH), not examined.

Extended diagnosis.

Males of T. keyserlingi  are similar to T. elongata  . Both species have a long body, a very long paturon, AXl and Gl placed on a common base and displaced to a lower position than the remaining lower teeth, and conductor tips not extended in tail-like projections ( Figs 5 A–JView Figure 5, 7A, C–EView Figure 7, 8 A–IView Figure 8, 10A, C, DView Figure 10, 20B, CView Figure 20; Levi 1981: pls 5g, i, 6h, i; Okuma 1992 sub T. maxillosa  : fig. 11 A–D, F). Tetragnatha keyserlingi  may be distinguished from T. elongata  by having pairs of black dots on the postero-dorsal region of the abdomen, ‘a’ placed closer to the external border of the paturon and directed upwards and outwards, ‘t’ present, ‘sl’ absent, a crest filling the gap from Gu to ‘T’, a large gap between ‘T’ and ‘rsu’, lower teeth onwards from L3 placed in a shallow concave row ( Figs 5 A–EView Figure 5, 7AView Figure 7, 8 A–EView Figure 8, 10AView Figure 10). Palps of both species are also similar, but those of T. keyserlingi  have shorter and wider tibias (2.3 × vs 4.7 ×), conductors with one pleat that only partially enfold the ribbon-like and twisted emboli, and paracymbia that are elongated, boomerang-shaped with slanted, basally projecting knobs and clearly visible translucent lobes ( Figs 8 H–JView Figure 8, 10 C–EView Figure 10, 20CView Figure 20). The epiandrous field has a spinning area which is not as high and without the depressed lateral areas found in T. elongata  ( Figs 7GView Figure 7, 10FView Figure 10).

Female chelicerae have elongated Gu, U2, and U3, where Gu is set apart from U2 by a very large gap and is located on an upper crest (CRu) ( Figs 9D, EView Figure 9, 10BView Figure 10). U2 and remaining upper side teeth form a row displaced to lower side of paturon, following the slanted fangs closing ( Figs 9D, EView Figure 9, 10BView Figure 10). AXl very small and located near Gl base and lower row with first three teeth on a lower crest (CRl); Gl straight, elongated, bulky, pointed, its base large, and projected slightly upwards ( Fig. 9E, FView Figure 9). Cheliceral fang enlarged in middle portion and apical third slanted and tapering to the acute tip, also harboring a narrow ridge ( Figs 9D, EView Figure 9, 10BView Figure 10). Internal genitalia unique, with two rounded spermathecae linked by two thick tubes to a median, slender and very elongated stalk, which places CS at a far anterior position ( Fig. 9IView Figure 9; Zhu and Zhang 2011, sub T. maxillosa  : fig. 123G).

Synonymy and notes.

This species is widespread in the Old World tropics and has been cited and illustrated many times under T. maxillosa  ( World Spider Catalog 2019), especially by Okuma (1983, 1987) and Zhu and Zhang (2011).

Tetragnatha keyserlingi  was named by Simon (1890: 134) for the specimens described and illustrated as T. mandibulata  by Keyserling (1865: 848, pl. 21, figs 6-9) from "Neu Granada" (currently Colombia) and T. mandibulata  ? by L. Koch (1872: 194, pl. 17, figs 2, 3) from Fiji (Ovalau), Samoa (Upolu), and Tonga in the Pacific. The illustrations by Keyserling (1865) and L. Koch (1872) already clearly show, for example, the large ‘T’ and small ‘t’ in male chelicerae and the characteristic Gu and Gl of the female chelicerae of T. keyserlingi  ( Figs 8D, E, GView Figure 8, 9 D–FView Figure 9, 10A, BView Figure 10).

Tetragnatha keyserlingi  was also recorded from Java (Indonesia) ( Thorell 1890: 221) and in his paper on Burmese spiders, Thorell (1895: 139) newly named this species as T. maxillosa  , based on the female from Java he described in 1890 and on males and females from Singapore collected by Cel. Workman; he pointed out that he considered T. maxillosa  to be distinct from T. keyserlingi  . One page later, he ( Thorell 1895: 140) named the specimens reported by L. Koch (1872) from the Pacific islands as another new species: T. kochi  , heavily relying on geographical distributions to separate the specimens from South America, Southeast Asia, and the Pacific Islands. The only morphological differences mentioned in his paper ( Thorell 1895: 139-140) are minor details in eye position and cheliceral teeth arrangement in females; no male characters were mentioned. In particular for T. maxillosa  and T. keyserlingi  , he compared the position of the second tooth on upper row of female chelicerae (U2 in our terminology) in relation to teeth of the lower row. According to Thorell, U2 of T. maxillosa  would face the 6th or 7th tooth of the lower row, while in T. keyserlingi  it would face the 4th or 5th tooth. However, the apparent position of teeth of one row in relation to the teeth of the opposite row is not easy to evaluate, as small changes on chelicerae inclination may change the apparent alignment. In addition, small changes in the relative position of teeth of the upper and lower rows are very common in this and other species.

We agree with Simon (1890) that the detailed illustrations given by Keyserling (1865) from "Neu Granada", and L. Koch (1872), from Pacific Islands ( Fig. 21HView Figure 21), allow the clear recognition of just one species, despite the great distances between localities. Moreover, the specimens from Southeast Asia that Thorell (1895) named T. maxillosa  also belong to the same widespread species. As Simon (1890) and Thorell (1895) had never seen the specimens they named as new species, no type specimens have ever been designated. No type or non-type material from the type localities of T. keyserlingi  or T. maxillosa  could be located in NHM, NMV, and ZMH. However, we received photos of two females from Upolu, collected in 1869 and deposited at NHRS, both identified as T. mandibulata  (labeled Museum Godeffroy, NHRS-GULI000069809). These specimens are surely part of the material which L. Koch (1872) designated and illustrated as " T. mandibulata  ?" ( Fig. 21HView Figure 21) and Thorell (1895) afterwards named T. kochi.  Thus, these specimens represent part of the type series of T. kochi  . As T. keyserlingi  Simon, 1890 was proposed five years before both Thorell’s names ( 1895), it is senior synonym of T. maxillosa  and T. kochi  .

Bösenberg and Strand (1906: 177, pl. 15, fig. 409 a–d) provided comprehensive illustrations of male and female chelicerae and genitalia of T. japonica  . Based on photos of the chelicerae of syntypes of both sexes from Osaka (Japan) deposited at ZMH ( Fig. 21 I–KView Figure 21), we confirm that the female is T. keyserlingi  ( Fig. 21IView Figure 21) and that the male actually belongs to T. nigrita  Lendl, 1866 ( Fig. 21J, KView Figure 21). Nonetheless, the illustrations of the male by Bösenberg and Strand (1906: fig. 409c, d) are like T. keyserlingi  , with a laterally directed apophysis, large Gu, absent or not noticeable ‘t’, and apical portion of embolus and conductor curved in a gentle slope. Thus, we consider that at least the originally illustrated male syntype belongs to T. keyserlingi  and that it may be deposited in SMF instead. The female specimen of T. japonica  should be considered as name bearing, as it was described, measured, and illustrated first by Bösenberg and Strand (1906: fig. 409a, b). We agree here with Okuma’s synonymy (1983) of T. japonica  with T. maxillosa  (= T. keyserlingi  ) and consider the male syntype from Hamburg and any other possible similar male syntype as misidentified specimens of T. nigrita  . Unfortunately, we were not able to examine the syntypes from Saga deposited in SMF.

Chamberlin (1924: 12, pl. 3, figs 21-23) described T. conformans  ( Fig. 21L, MView Figure 21) and T. cliens  Chamberlin, 1924 ( Fig. 21 N–QView Figure 21), each based on a couple from Suzhou [Soochow on the labels ( Fig. 21P, QView Figure 21), but Kuliang (Fuzhou) in the original paper], China. Later, Schenkel (1936: 89-91, fig. 31) described T. propioides  based on a couple from Sichuan, also in China. All were separately synonymised with T. keyserlingi  (under T. maxillosa  or its junior synonyms): Zhu (1983) for T. conformans  (sub T. japonica  ) and Okuma (1983: 72, 73) for T. japonica  , T. cliens  , and T. propioides  .

Another mismatching of T. keyserlingi  and T. nigrita  occurred with the type series of T. cliens  , as observed by Song (1988: 127), who removed T. cliens  from the synonymy with T. maxillosa  . The male holotype of T. cliens  is clearly T. nigrita  and was wrongly coupled with the female, which belongs to T. keyserlingi  ( Fig. 21N, OView Figure 21). Song (1988) noted that the male was labeled as “type” and the female as “paratype” in the original vials in USNM ( Fig. 21P, QView Figure 21). Like Song (1988), we were also able to analyse the type material and agree with the synonymy. Nonetheless, this mismatching was not noticed by Okuma (1983), who probably did not analyse the type material and, years before Song, wrongly synonymised T. cliens  with T. maxillosa  , surely based on the order of description and illustrations of the original paper. Summing up, we agree with the synonymies for T. conformans  ( Fig. 21L, MView Figure 21), T. japonica  ( Fig. 21IView Figure 21) and T. cliens  ( Fig. 21N, PView Figure 21), according to original descriptions and illustrations and type photos we received. Additionaly, we also confirm the synonymy of T. propioides  (see Schenkel 1936: fig. 31), but its syntypes were not located.

Finally, T. ethodon  was described by Chamberlin and Ivie (1936: pl. 17, figs 144-146) based on specimens from both sexes collected in Panama. This species was redescribed by Chickering (1957c: 316, figs 27-31) who transferred Chamberlin and Ivie’s females to T. tenuissima  O. Pickard-Cambridge, 1889 and pointed out that the rather damaged male holotype was the only known specimen of the species from Panama. Okuma (1992: 228, fig. 7) also redescribed and illustrated T. ethodon  , expanding its distribution to Puerto Rico and Barbados and adding a new description for females. She pointed out that this species was very similar to T. maxillosa  (= T. keyserlingi  ) and separated both species by its wider genital fold. Comparing our specimens with previous illustrations under T. maxillosa  , we consider the differences pointed out by Okuma (1992) to fall within the observed intraspecific variations, and hereby synonymise T. ethodon  with T. keyserlingi  .

Variation.

Males (n = 11): total length, 5.29-7.28; females (n = 14): total length, 6.59-9.03. In Okuma (1968 sub T. japonica  , 1983, 1992 under T. ethodon  ) and Bösenberg and Strand (1906 under T. japonica  : fig. 409a), there is no visible upper crest (CRu) or lower crest (CRl). In fact, female syntypes of T. kochi  ( Fig. 21KView Figure 21), the paratype of T. cliens  and holotype of T. conformans  ( Fig. 21M, OView Figure 21) do not have crests on the paturon. In contrast, other publications (e.g. Okuma 1987, 1988b, Zhu and Zhang 2011), the female syntype of T. japonica  from Osaka ( Fig. 21IView Figure 21), and all female specimens we examined from South America clearly possess CRu and CRl. So far, we cannot disregard the possibility that the absence of crests in some of the illustrated specimens is real or simply an artefact of poor illustration.

Distribution.

Pantropical, including Africa, Asia, Polynesia, Central America, and Brazil ( Fig. 22CView Figure 22).