Tetragnatha chiyokoae, Castanheira & Baptista, 2020

Castanheira, Pedro De Souza & Baptista, Renner Luiz Cerqueira, 2020, Notes on slender species of the long-jawed spider genus Tetragnatha (Araneae Tetragnathidae) with description of three new species, Zootaxa 4768 (1), pp. 43-75 : 56-59

Tetragnatha chiyokoae new species

( Figs 7 , 8 )

Tetragnatha sp.: Chu & Okuma, 1970: 74, fig. 5A–D

Tetragnatha chauliodus: Okuma, 1988b: 196 , fig. 11A–L (misidentified)

T. chauliodus: Tanikawa, 1990: 9 , figs 1–9 (misidentified)

T. chauliodus: Okuma et al., 1993: 44 , fig. 40A–G (misidentified)

T. chauliodus: Song et al., 1999: 221 , figs 126A, G, W, X, 127A, B (misidentified)

T. chauliodus: Zhu et al., 2003: 128 , figs 59A–G, 60A–G (♂ misidentified)

T. chauliodus: Tanikawa, 2007: 108 , figs 401, 402, 865–867 (misidentified)

T. chauliodus: Tanikawa, 2009: 416 , figs 107–109 (misidentified)

Type material. Holotype ♂. CHINA, Yunnan: Menglong county (21°54’N, 101°12’E), 29.VII.2000, M. Zhu, F. Zhang, J. Zhang leg. ( MHBU 331 ) ; Paratypes. CHINA, Yunnan: Menglong county (21°54’N, 101°12’E), 29.VII.2000, M. Zhu, F. Zhang, J. Zhang leg., 1 ♂ ( MHBU) ; JAPAN, Iriomotejima Is.: Okinawa prefecture (24.372960 N, 123.754107E), 31.III.1996, A. Tanikawa leg., 1 ♂, 1 ♀ ( UFRJ 1633 ); 11.VIII.1999, A. Tanikawa leg., 1 ♂, 1 ♀ (NSMT-Ar 17244); 26.III.2000, A. Tanikawa leg., 1 ♂ (NSMT-Ar 17243); 10.VIII.2000, A. Tanikawa leg., 1 ♂ (NSMT-Ar 17242) .

Additional material examined. None.

Etymology. The specific epithet is given in honor to the late Japanese researcher Dr. Chiyoko Okuma (Kyushu University), first arachnologist to illustrate this species and one of most important taxonomists who worked on Tetragnatha .

Diagnosis. Male chelicerae of T. chiyokoae new species is similar to T. chauliodus , as both bear elongated ‘a’, Gu, ‘T’ and Gl, AXu absent and AXl extremely reduced ( Figs 7 B–D, 9D–G). However, the new species can be set apart by the following characteristics: paturon more elongated and thinner, ‘a’ with longer tip, ‘t’ absent, Gu thicker, slightly displaced from teeth row and distalward projected, ‘T’ much thicker with wider basis, Gl with much larger basis and apart from L2 by a very large gap ( Fig. 7 B–D). Palps of both species share thin conductor covering the very esclerotized embolus as a thin pouch with large terminal cap and paracymbium with undivided notch, with very wide translucent lobe and large knob ( Figs 7 E–G, 9H–J). T. chiyokoae new species can be distinguished by longer tibia, narrower terminal cap of the conductor, embolus with straight tip and paracymbium with slanted notch, translucent lobe darker and almost reaching up the notch and knob in a more elevated position ( Fig. 7 E–G).

Females of T. chiyokoae new species are more alike those of T. chauliodus and T. tenuissima sharing besides the slender and elongated abdomen with black lateral patches, similar chelicerae with elongated upper crests (CRu) upon a deep furrow just over the upper row proper and Gu similar in shape and size ( Figs 8A , 10D, E , 13C, D , 14C ; Okuma 1988b, fig. 40B; Tanikawa 1990, fig. 4). T. chauliodus and T. chiyokoae new species are set apart by chelicerae having only Gu on CRu and apart from U2 by large gap, larger Gl, longer L2, and by the fang bearing a basal cusp (BC), besides having longer genital fold ( Fig. 8A, B , 10 E–G; Okuma 1988b, fig. 40B, F; Tanikawa 1990, figs 3–5). Finally, T. chiyokoae new species differs from T. chauliodus by the following characteristics: longer paturon, Gu heavily sclerotized and with a thin basis, located on the top of a thin ridge, Gl bulkier, longer, almost straight and pointed inward, L2 smaller, fangs sinuous, with midway conspicuous concavity followed by a distal keel at its inner margin, with small or absent MC ( Fig. 8A, B , 10 D–G).

Notes. We recognized this species while studying T. chauliodus (for more details, see below on that species section). We dubitatively associate females with a very small or absent MC with the males of T. chiyokoae new species, as they have been collected together or at the same locality a handful of times (e.g. Okuma 1988b, Tanikawa 1990, Song et al. 1999, Zhu et al. 2003). We analyzed the taxonomic literature including descriptions of Oriental and Australasian species of Tetragnatha and have not found any previously described species that matches T. chiyokoae new species or any of the new species described in this paper. The first illustration of T. chiyokoae new species was from a male collected in rice paddies of Taiwan ( Chu & Okuma 1970, as Tetragnatha sp.). Both sexes of this species have been repeatedly misidentified, redescribed and illustrated as T. chauliodus , with records and illustrations for Taiwan ( Okuma 1988b), Japan ( Tanikawa 1990), and China ( Song et al. 1999; Zhu et al. 2003). As discussed under T. chauliodus, Zhu et al. (2003) mismatched two different males ( T. chauliodus and T. chiyokoae new species) and only one kind of female (typical T. chauliodus ), all collected in the same area of Yunnan Province, southwest China. We highlight that we did not have direct access to the specimens, so a patterned description following the usual formula was not possible.

Natural History. Unknown.

Distribution. From southwest China and Japan, and also Taiwan, following illustrations by Chu & Okuma (1970) and Okuma (1988b).

Figures

FIGURE 7. Tetragnatha chiyokoae new species male holotype: A, dorsal habitus. B–D, left chelicera; B, upper view. C, inner view. D, lower view. E–G, left palp; E, mesal view. F, dorsal view. G, ventral view (paracymbium). Scale bars, A, 2 mm; B, C, D, 0.5 mm; E, F, G, 0.2 mm. Photos, Feng Zhang.

FIGURE 8. Tetragnatha chiyokoae new species female paratype (NSMT-Ar 17244): A, B, left chelicera; A, upper view. B, lower view. * = midway conspicuous concavity. Photos, Akio Tanikawa.

FIGURE 10. Tetragnatha chauliodus female (UFRJ 1313): 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, genital fold, ventral view. Scale bars, A, B, C, 2 mm; D, E, F, G, H, 0.2 mm.

FIGURE 13. Tetragnatha tenuissima female: A, dorsal habitus (UFRJ 1534). B, lateral habitus (UFRJ 1534). C, ventral habitus (UFRJ 1534). D–G, left chelicera (UFRJ 1534); D, upper view. E, inner view. F, lower view. G, outer view. H–I, female genitalia; H, genital fold, ventral view (UFRJ 1534). I, internal genitalia, dorsal view (UFRJ 1520). Scale bars, A, B, C, 2 mm; D, E, F, G, 0.5 mm; H, 0.2 mm; I, 0.1 mm.

FIGURE 14. Tetragnatha tenuissima new species SEM photos: A–B, male left chelicerae (MPEG 031350); A, upper view. B, lower view. C–D, female left chelicerae (UFRJ 1534); C, upper view; D, lower view. E–G, left male palp (MPEG 031349); E, mesal view. F, embolus detail, ventral view. G, paracymbium detail, ventral view. H, epiandrous detail, ventral view (MPEG 031350). Scale bars, A, B, C, D, E, 0.2 mm; F, H, 0.02 mm; G, 0.1 mm.