Tetragnatha tenuissima O. Pickard-Cambridge, 1889

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 : 65-71

Tetragnatha tenuissima O. Pickard-Cambridge, 1889

( Figs 12–15 ; Map 3)

Tetragnatha tenuissima O. Pickard-Cambridge, 1889: 9 , pl. 3, fig. 1, 2 (♂ ♀).

Tetragnatha filiformis Taczanowski, 1872: 111 (♂ ♀; preoccupied by Audouin, 1826 sub Eugnatha ).

Tetragnatha filiformata Roewer, 1942: 989 (replacement name) syn. nov.

Type material. Tetragnatha tenuissima : GUATEMALA: ♂ ♀ syntypes, Coban, Tamahu ( NHM), examined. Tetragnatha filiformata : FRENCH GUYANA: 2♂, 7♀, 11 immature syntypes, Cayenne ( MIZ 225510, MIZ 225510– 225516, MIZ 225511–225516, MIZ 225517–225523), examined; BRAZIL: 2♂, 3♀, 1 immature syntypes, Amapá, Uaçá [Uassa, under French Guyana] ( MIZ 225524–225529), loaned and examined.

Material examined. ARGENTINA, Misiones: Iguazú Falls , XI.1954, B. C. Schiapelli leg., 1 ♂ ( MACN 39612 ex MACN 24256 ) ; BRAZIL, Bahia: Lagoinha: O. Leonardos, 1 ♀, 1 immature ( MNRJ 53948 ); Espírito Santo: Santa Tereza : Estação Biológica de Santa Lúcia , 11–12.V.2005, A. Giupponi et al. leg., 1 ♀ ( MNRJ 06922 ); Sooretama : REBIO Sooretama (Córrego Quirininho) , 01.V.2009, F. F. F. Moreira leg., 1 ♀ ( UFRJ 0192 ); Mato Grosso: Chapada dos Guimarães: 20–29.vii.2000, C. Strüssman leg., 2 ♂ ( MCTP 43338 ex 11314); Xingu river , H. Leon- ardos leg., 2 ♀ ( MNRJ 02595 ex 01177); Pará: Rio Cuminá , G. Cruls leg., 1 ♀ ( MNRJ 410 ); idem, 1 ♀ ( MNRJ 14170 ); Jacareacanga: Flona do Crepori , 6°08’56.9’’S, 57°14’45.96’’W, 25.X.2009, E. G. S. Cafofo leg., 1 ♂ ( MPEG 031347 ); Melgaço: Estação Ecológica Ferreira Penna , Flona de Caxiuanã , 01°44’22.7”S, 51°27’22.2’W, 30.IX.2005, C. B. Lopes leg., 1 ♂ ( MPEG 031345 ); Piauí: Castelo do Piauí : ECB Rochas Ornamentais LTDA, Fazenda Bonito, 05°13’50.8’’S, 41°42’1.1’’W, L. S. Carvalho leg., 2 ♂ ( MPEG 031349 ); idem, 1 ♂, 1 immature ( MPEG 031350 ); Paraná: Morretes: Serra da Graciosa , 09–20.I.1995, 1 ♂, 2 ♀ ( MCTP 6944 ); Rio Negro : 1 immature ( MNRJ 52283 ); Rio de Janeiro: Cachoeiras de Macacu : Reserva Ecológica de Guapiaçu , Lagoa, 02.IX.2017, H. Schinelli leg., 1 ♀ ( UFRJ 1473 ); 17.XII.2017, R. Baptista leg., 1 ♂ ( UFRJ 1564 ); Casimiro de Abreu : Túlio, Ponto 4, 04.VIII.2010, looking down, P. Castanheira leg., 1 ♀ ( UFRJ 1567 ); idem, 04–11.VIII.2010, D. T. Castro leg., 1 ♀ ( UFRJ 1568 ); Mangaratiba: Reserva Ecológica Rio das Pedras, 24.V.2009, Entomologia UFRJ leg., 1 ♂ ( UFRJ 0179 ); São Paulo: Itú: Fazenda Pau D’Alho, 17–18.IX.1960, P. Biasi leg., 3 immatures ( MZUSP 74669 ); Juquiá: 26–27.IV.1948, F, Lane leg., 1 ♂ ( MZUSP 1172 ); São Carlos: Várzea do Rio Quilombo (Jusante BR 116 ), 17.II.1990, P. Gnaspini leg., 1 ♂ ( MZUSP 11984 ); Ubatuba: PE Serra do Mar , Núcleo Picinguaba, 30.V–02.VI.2007, R. Baptista et al. leg., 2 immatures ( UFRJ 1569 ); idem, 29.X–02.XI.2008, R. Baptista leg., 1 ♀ ( UFRJ 1570 ); GUY- ANA: Itamyaruma, Essequibo River , 29.VIII.1936, Romiti leg. ( MZUF) .

Diagnosis. Chelicerae and palps of males of T. tenuissima are very different from all other species described above. Males bear chelicerae with AXu almost as a nub, elongated and robust ‘sl’, displaced upwards from the row and located near Gu, which is robust and curved basalwards, AXl very reduced and located near base of fang (only visible on SEM photos) and Gl finger-like distalward projected and palps with short and T-like paracymbium. Female chelicerae are comparable with T. chiyokoae new species and T. chauliodus (see previous diagnoses above), differing from them by Gu and U2 with almost the same size and located apart by a very small gap, BC absent, OC present, and internal genitalia with slender central membranous sac (comparing to T. chauliodus , figs 8A, B, 10D–F, 12C–F, I; 13C, H; 14A–D, G; Zhu et al. 2003, fig. 59G).

Description. Male (UFRJ 1534): Carapace yellow, elliptic ( Fig. 12A ). Labium brown and very elongated ( Fig. 12B ). Sternum light brown contoured in dark brown ( Fig. 12B ). Eyes parallel and procurved, ringed in black, AME smaller than others and touching PME ( Fig. 12A ). Legs yellow and very elongated ( Fig. 12A, B ). Paturon thick, more than 3x longer than wide and little over 1.2x longer than carapace, moderately curved outwards, around 45° from the median line of the body ( Figs 12A, C , 14A, B ). ‘a’ very elongated, carved on its apex with large base, clearly bent upper and outward from middle to the apex, occupying most of chelicera width ( Figs 12C, D, F , 14A ). AXu small and not pointed, with large basis, almost as a nub ( Figs 12C, D , 14A ). ‘t’ reduced, thick and located after the basis of Gu ( Figs 12C, D , 14A , 15A ). Upper row with eight uneven teeth ( Figs 12C, D, F ; 14A ): Gu very sclerotized, elongated, slanted, with large basis and pointed basalward; ‘sl’ with elongated and sclerotized basis, pointed, clearly pointing up and distalward, located adjoined to the basis of Gu and displaced from the row itself; ‘T’ thorn-like, very elongated, thin, and almost straight, slightly displaced from the row itself and ‘rsu’ with five teeth decreasing in size with last two teeth very reduced, almost denticles. AXl extremely reduced ( Fig. 14B ) Lower row with thirteen teeth ( Figs. 12D, E ; 14B ): Gl bulky, thick, finger-like and pointing distalward; L2 thick, pointed, almost straight and much longer and bulkier than remaining teeth; L3–L 7 in a smooth depression, L3 and L7 slightly longer than L4–L6; L8–L11 decreasing in size and located after a small gap apart from L7; L12 and L13 with almost the same size and located after a small gap from L11, apart from another gap. Cheliceral fang as wide as its basis, wavy in the middle portion and inserted between the rows of teeth ( Figs. 12 C–E; 14A, B). Abdomen cylindrical, slender, dorsally pale yellow, covered by guanine spots, scantier at the middle line, and five dark gray to black pair of spots on its edge ( Fig. 12A ). Venter pale brown, flattened and nude, with neither drawings nor patches ( Fig. 12B ). Epiandrous small, with a narrow division midway, with five fusules on left side and only three on right side ( Fig. 14H ). Palps bearing a very short and triangular tibia, and an elongated cymbium, bearing a thin basis and wide cymbial tarsal organ, strongly developed and deep ( Figs. 12G, H ; 14E ); tegulum spherical and inflated, more than two times wider than high, with a constriction near the basis of embolus ( Figs. 12 G–I; 14E); conductor thin, transparent, slanted and straight, tapering towards its apex, with thin edges enfolding over most of the embolus ( Figs. 12 G–I; 14E, F); embolus with a thick basis, originating at middle portion of the bulb, near the cymbium, with rounded curve at initial portion, followed by a strong upward curve, ending in filiform curved thin apex and only being exposed, from behind the conductor, in the terminal end ( Figs. 12 G–I; 14E, F); paracymbium very small, triangular, not slanted, with rounded and thick notch, thin translucid lobe and long, thick, sclerotized and elevated knob at the ectal side ( Figs. 12I , 14G ).

Total length 7.20. Carapace 1.64 long, 1.09 wide. Abdomen 5.90 long, 0.66 wide. Left chelicera 1.90 long, 0.43 wide. Leg formula I–IV–II–III. Leg I: femur 8.73, patella 0.84, tibia 7.92, metatarsus 8.70 and tarsus 1.48. Leg II: patella + tibia 5.35. Leg III: patella + tibia 1.75. Leg IV: patella + tibia 4.50.

Female (UFRJ 1534): Carapace colour, endites, fovea, eyes, labium, legs and sternum as in male ( Fig. 13A, B ). Paturon with same colour as male, around 4,7x longer than wide and curved outwards, around 50° from median line of the body ( Figs. 13 A–F; 14C, D). AXu and AXl absent. Upper row with nine teeth ( Figs. 13C, D ; 14C ): Gu next to base of fang, slightly distalward, thick and finger-like, located on outer- and distal end of CRu; U2 thin, pointed and slightly distalward, apart from Gu by a small and from U3 by a large gap; U3–U9 decreasing in size; U3 with large basis longer than U2 and U7 and U8 sharing same basis. Lower row with ten teeth ( Figs. 13D, E ): Gl finger-like and initially distalward, with its tip being basalward, apart from L2 by a marked crest; L2–L3 and L3–L4 apart by small gaps; L2 distalward, pointed, with large basis; L3 and L4 much smaller; L5–L10 decreasing in size. Fang wavy, constricted midway forming a conspicuous curve and inserting between both rows of teeth, bearing a small outer cusp on its top ( Figs. 13C, E, F ; 14C, D ). Abdomen as male, around 2.7x longer than carapace, differing by better marked gray spots on the dorsum ( Fig. 13A, B ). Genital fold short, approximately 2x wider than long and laterally compressed, with thick and straight tip ( Fig. 13G ). Internal genitalia composed of two slender, rounded and elongated spermathecae, more sclerotized on outer edge and a pointed, elongated and sclerotized central membranous sac, basally positioned in comparison to the spermathecae ( Fig. 13H ).

MAP 3. Distribution of the specimens of T. tenuissima we analyzed.

Total length 8.23. Carapace 2.06 long, 0.90 wide. Abdomen 6.34 long, 0.80 wide. Left chelicera 1.94 long, 0.38 wide. Leg formula I–IV–II–III. Leg I: femur 7.28, patella 0.68, tibia 7.80, metatarsus 6.93 and tarsus 1.71. Leg II: patella + tibia 4.66. Leg III: patella + tibia 1.47. Leg IV: patella + tibia 4.12.

Variation. Males (n = 4): total length, 6.78 – 7.29; females (n = 6): total length, 7.51 – 9.45. The outer cusp (OC) may sometimes not be present on the chelicerae of females.

Synonymy and notes. The first author was gently received at MIZ-PAN and NHM collections where type-material of T. filiformata Roewer, 1942 ( Guyana, French Guyana and Brazill: Amapá) and T. tenuissima ( Guatemala) were examined, respectively. Taczanowski (1872) described Tetragnatha filiformis , preoccupied and posteriorly replaced by the name T. filiformata by Roewer (1942). Taczanowski’s description of T. filiformis is very comprehensive, allowing the recognition of described specimens. The typical elongated chelicerae seen in males and females syntypes of T. filiformata ( Fig. 15A, B ) is also observed in the type-material of T. tenuissima (O. Pickard-Cambridge 1889, pl. 3, figs 1, 2), subsequent revisions (e.g. Okuma 1992, fig. 21) and in all specimens we identified for South America. We therefore propose a new synonymy, Tetragnatha filiformata Roewer, 1942 = Tetragnatha tenuissima O. Pickard-Cambridge 1889 new synonymy.

Furthermore, the type-localities of both species are compatible with the synonymy herein proposed if we consider the broad distribution of T. tenuissima in the Neotropical region. This species has been previously recorded for Guatemala (O. Pickard-Cambridge 1889; Okuma 1992), Puerto Rico ( Petrunkevitch 1930a,b; Okuma 1992), Cuba (Bryan 1940; Okuma 1992), Hispaniola ( Bryant 1945), Jamaica ( Chickering 1957b, 1962), Panama ( Chickering 1957c; Okuma 1992), Costa Rica ( Okuma 1992), Mexico ( Okuma 1992). Herein, we add many records from throughout Brazil and Argentina.

Habitat notes. Alongside T. megalocera new species and T. chauliodus , this species seems not to be associated to water, as duly observed by the authors, with the majority of specimens being collected only in the interior of forest remnants.

Distribution. From Mexico to Argentina. In Brazil, this species can be found in all regions of the country (Map 3).

Nomina dubia

The types of the following species are immature, not allowing a precise recognition. In all cases, we cannot correctly identify these species, nor clearly diagnose them in relation to other slender-bodied species described above. Furthermore, it is impossible to ascribe the immature specimens to any of the above cited species, because the not fully developed chelicerae and genitalia are not comparable to the adult’s diagnostic characters. Therefore, we consider all species listed below to be nomina dubia, or more precisely, species inquirendae.

Figures

FIGURE 12. Tetragnatha tenuissima male (UFRJ 1534): A, dorsal habitus. B, ventral habitus. C–F, left chelicera; C, upper view. D, inner view. E, lower view. F, outer view. G–I, left palp; G, mesal view. H, dorsal view. I, ventral view (paracymbium). Scale bars, A, B, 2 mm; C, D, E, F, G, H, I, 0.5 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.

FIGURE 15. Tetragnatha tenuissima sub Tetragnatha filiformata, syntypes: A, male chelicerae, upper view (MIZ 225524- 225529). B, female chelicerae, upper view (MIZ 225524-225529). C, labels of specimens from Cayenne, French Guyana. Scale bars, A, B, 1 mm.