Taraire, Álvarez-Padilla & Kallal & Hormiga, 2020

Álvarez-Padilla, Fernando, Kallal, Robert J. & Hormiga, Gustavo, 2020, Taxonomy And Phylogenetics Of Nanometinae And Other Australasian Orb-Weaving Spiders (Araneae: Tetragnathidae), Bulletin of the American Museum of Natural History 2020 (438), pp. 1-107 : 1-107

Genus Taraire , gen. nov.

Figures 45–50 , 55

Type species: Linyphia rufolineata Urquhart, 1889 .

DIAGNOSIS: Taraire species resemble the large species of Nanometa in their internal female reproductive anatomy (fig. 48C, D), and the monotypic Tawhai by the projected epigynal plate (figs. 47A, B, 51D) and male cymbial processes (figs. 46A–H, 52A–D). However, Taraire females can be consistently separated from Nanometa by having the posterior edge of the epigynum extending below the epigastric furrow (fig. 47A, B). Tawhai arborea differs from Taraire species in that the former genus has a protruded epigynum with short and sclerotized copulatory ducts (figs. 51H, 54F); in Taraire the copulatory ducts are much longer (fig. 49E) and inside membranous sacks (fig. 47E, F). Males of Taraire can be separated from those of Nanometa by the presence of one large heavily sclerotized embolic apophysis attached to the embolic base through a membrane (figs. 45F, 46A, B, 49A–C, 50A–C). In Taraire the tegulum is basally displaced and cup shaped (figs. 46A, B, 49A, B, 50A, B), unlike the donut-shaped and dorsoventrally compressed tegulum of Nanometa (figs. 10C, F, 13A, B). Taraire species lack the booklung plate stridulatory organs found in Nanometa . In Taraire the conductor is considerably larger than the embolic apophysis and completely encloses a filiform embolus (fig. 45F), while in Tawhai the conductor is small and rectangular in shape, and partially enclosing a thicker embolus (fig. 52A, C).

DESCRIPTION: Female total length 4.95–5.57. Cephalothorax length 2.35–2.87, width 1.85– 2.27. Carapace glabrous, pale yellow or yellow, dark brown only over the cephalic region. Fovea deep, transversal, carapace dorsal pits absent (fig. 45A). Clypeus height 0.9 to 1.3 AME diameter, cuticle darker around the eyes and over the cheliceral boss (fig. 45B). Anterior eyes slightly larger than posterior eyes. Lateral eyes on the same tubercle, one AME diameter apart from median eyes and approximately half that size. Chelicerae with few scattered setae, cuticle smooth (fig. 45B), with three pro- and two retromarginal teeth, with ca. two cheliceral denticles. Endites longer than wide, dark brown, internal margins pale yellow. Labium rectangular, wider than long, colored as the endites. Sternum pale yellow to yellow, trapezoidal in shape, wider between the first two legs (fig. 45C). Abdomen dorsum: background pale to dark gray, white guanine patches concentrated on two anterior spots, anterior margin covered by a wide dark-brown band of patches, that continues posteriorly as three to four dark-brown chevrons (fig. 45A). Ventral surface with median dark-brown longitudinal line, flanked by two lines of guanine white patches (fig. 45C). Lateral sides with a reticulated pattern of guanine and dark-brown patches (fig. 45E). Booklung covers without stridulatory striae. Spinnerets pale yellow to brown, lighter pattern on internal surfaces. Ultrastructure of abdomen and spinnerets observed with SEM. Abdomen cuticle flat reticulated, all tracheae tube shaped, median tracheae with leaf-shaped tips. ALS with one major ampullate, one nubbin, ca. 70 piriform, tartipores numerous. PMS with one minor ampullate, one nubbin, and one cylindrical and three central aciniform spigots. PLS araneoid triplet separated at the base and tips, ca. 12 aciniform spigots distributed in two parallel rows, two cylindrical gland spigots at periphery. Leg formula 1-2-4-3. Femur I length 3.23– 3.79. First pair considerably larger. Background of all legs yellow to dark yellow and covered with dark-brown annuli. Femora without trichobothria, few setae present, other segments hirsute, increasing after tibiae. Epigynum: rectangular shape, wider than long. Copulatory openings located on the posterior margin (figs. 47C, D, 48A, B). Internal epigynal structures similar to those found in Nanometa . Copulatory ducts modified as membranous sacs and separated from the spermathecae giving the appearance of four receptacles (fig. 48C, D). Accessory duct glands clustered on puffball-shaped clusters. Fertilization ducts short, straight (figs. 49E, 50E).

Male same as female except as noted. Total length 4.81–5.73. Cephalothorax length 2.47– 2.59, width 1.99–2.15. Clypeus height 0.64–0.95 AME diameter (fig. 45D). Chelicerae darker than female, slightly longer and narrower, dorsal cuticle rugose (fig. 45D). Abdominal pattern as in female, but lighter. Femur I length 4.43–5.58. Pedipalpal tibia triangular, 1.3 times longer than wide, apical margin wider. CEBP short and heavily sclerotized cuticular ridge, with or without spines (figs. 46B, 49A, 50A), CEMP spine shaped, long and completely separated from the cymbium (fig. 48E, F). Paracymbium finger shaped and hirsute (figs. 46G, H). Tegulum basally displaced and cup shaped (figs. 49A, B). Conductor margins sclerotized, central part membranous (it did not expand with lactic acid), completely covering the embolus and variable in shape between species (figs. 49A–C, 50A–C). Embolus long, filiform, and flexible. Embolus basal apophysis attachment membranous, basal apophysis heavily sclerotized and formed by one sclerite partially divided by a membrane (figs. 45F, 49B).

COMPOSITION: Taraire rufolineata and Taraire oculta .

SYSTEMATICS: Taraire is sister to Tawhai (figs. 61–63), but the placement of the lineage including these two genera is unstable across phylogenetic analyses. Putative morphological synapomorphies supporting the monophyly of Taraire include the apically acute, digitiform CEMP pointing anteriorly (figs. 46D, 49C), the narrowing of the conductor margin (which encloses the filiform embolus), as seen in ventral view (figs. 46A, B, 49A, 50A), and sclerotized, horizontal fertilization ducts (figs. 47E, F, 49E, 50E).

ETYMOLOGY: The genus is named after the Māori word for the New Zealand endemic tree Beilschmiedia tarairi A. Cunnimgham (Lauraceae) . Taraire is indeclinable and feminine in gender.

DISTRIBUTION: Taraire is found on the North, South and Stewart islands of New Zealand (fig. 55).

NATURAL HISTORY: Taraire builds vertical orb webs. They rest at the central hub with two legs forward and the fourth pair pointed back (fig. 3A, B). The webs can be located near the forest floor, such as under rock shelves (G.H. and R.K., personal obs.).

Figures

FIGURE 45. Taraire rufolineata (TEAU029; A–E) and T. oculta (TEAU042; F). A. Female, dorsal habitus. B. Female, frontal habitus. C. Female, ventral habitus. D. Male, frontal habitus. E. Female, lateral habitus. F. Pedipalp, apical (expanded). Scale bars: A–D, 1.0 mm; F, 0.2 mm.

FIGURE 46. Taraire rufolineata (TEAU030; A, C, E, G) and T. oculta (TEAU032; B, D, F, H), pedipalps. A, B. Ventral. C, D. Dorsal. E, F. Mesal. G, H. Ectal. Scale bars: 0.2 mm.

FIGURE 47. Taraire rufolineata (TEAU029; A, C, E) and T. oculta (TEAU031; B, D, F), epigyna. A, B. Ventral. C, D. Caudal. E, F. Dorsal digested. Scale bars: 0.2 mm.

FIGURE 48. Taraire oculta (TEAU042; A, C, E, G) and T. rufolineata (female: TEAU043; male: TEAU046; B, D, F, H). A, B. Epigynum, caudal. C, D. Epigynum, dorsal. E, F. CEBP and CEMP, detail. G, H. Conductor and embolus apical detail. Scale bars: 0.2 mm.

FIGURE 49. Taraire rufolineata (male: TEAU030; female: TEAU043). A. Pedipalp, ventral. B. Pedipalp, ectal. C. Pedipalp, dorsal. D. Epigynum, ventral. E. Epigynum, dorsal. Scale bars: A–C, 0.5 mm; D, E, 0.2 mm.

FIGURE 50. Taraire oculta (male: QM S58330; female: TEAU042). A. Pedipalp, ventral. B. Pedipalp, ectal. C. Pedipalp, dorsal. D. Epigynum, ventral. E. Epigynum, dorsal. Scale bars: A–C, 0.5 mm; D, 0.2 mm; E, 0.1 mm.

FIGURE 55. Distribution of Taraire and Tawhai in New Zealand.